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Milović, Miloš

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  • Milović, Miloš (38)

Author's Bibliography

Supplementary information for the article: Jugović, D., Milović, M., Popović, M., Kusigerski, V., Škapin, S., Rakočević, Z., Mitrić, M., 2019. Effects of fluorination on the structure, magnetic and electrochemical properties of the P2-type NaxCoO2 powder. Journal of Alloys and Compounds 774, 30–37. https://doi.org/10.1016/j.jallcom.2018.09.372

Jugović, Dragana; Milović, Miloš; Popović, Maja; Kusigerski, Vladan; Škapin, Srečo Davor; Rakočević, Zlatko; Mitrić, Miodrag

(2019)

@misc{
author = "Jugović, Dragana and Milović, Miloš and Popović, Maja and Kusigerski, Vladan and Škapin, Srečo Davor and Rakočević, Zlatko and Mitrić, Miodrag",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/5970",
journal = "Journal of Alloys and Compounds",
title = "Supplementary information for the article: Jugović, D., Milović, M., Popović, M., Kusigerski, V., Škapin, S., Rakočević, Z., Mitrić, M., 2019. Effects of fluorination on the structure, magnetic and electrochemical properties of the P2-type NaxCoO2 powder. Journal of Alloys and Compounds 774, 30–37. https://doi.org/10.1016/j.jallcom.2018.09.372"
}

Structural and electrochemical properties of the Li2FeP2O7/C composite prepared using soluble methylcellulose

Jugović, Dragana; Mitrić, Miodrag; Milović, Miloš; Ivanovski, Valentin N.; Škapin, Srečo Davor; Dojčinović, Biljana; Uskoković, Dragan

(Elsevier, 2019)

TY  - JOUR
AU  - Jugović, Dragana
AU  - Mitrić, Miodrag
AU  - Milović, Miloš
AU  - Ivanovski, Valentin N.
AU  - Škapin, Srečo Davor
AU  - Dojčinović, Biljana
AU  - Uskoković, Dragan
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/4938
AB  - A new method involving the homogeneous dispersion of precursor compounds inside a methylcellulose matrix is used for the synthesis of a composite powder of Li 2 FeP 2 O 7 and carbon. The properties of carbon-containing and carbon-free powders are studied by X-ray powder diffraction (XRD) including Rietveld refinement, Mössbauer spectroscopy, Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), galvanostatic cycling, and electrochemical impedance spectroscopy (EIS). The structure of both powders is refined in a monoclinic framework (space group P2 1 /c). The structural refinement and Mössbauer spectroscopy reveal different degrees of partial occupancy of mixed-occupied sites by lithium. Electrochemical measurements show that the in situ formation of carbon improves capacity (90% of 1-electron theoretical capacity) through decreased charge-transfer resistance. © 2019 Elsevier B.V.
PB  - Elsevier
T2  - Journal of Alloys and Compounds
T1  - Structural and electrochemical properties of the Li2FeP2O7/C composite prepared using soluble methylcellulose
SP  - 912
EP  - 919
VL  - 786
DO  - 10.1016/j.jallcom.2019.01.392
ER  - 
@article{
author = "Jugović, Dragana and Mitrić, Miodrag and Milović, Miloš and Ivanovski, Valentin N. and Škapin, Srečo Davor and Dojčinović, Biljana and Uskoković, Dragan",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/4938",
abstract = "A new method involving the homogeneous dispersion of precursor compounds inside a methylcellulose matrix is used for the synthesis of a composite powder of Li 2 FeP 2 O 7 and carbon. The properties of carbon-containing and carbon-free powders are studied by X-ray powder diffraction (XRD) including Rietveld refinement, Mössbauer spectroscopy, Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), galvanostatic cycling, and electrochemical impedance spectroscopy (EIS). The structure of both powders is refined in a monoclinic framework (space group P2 1 /c). The structural refinement and Mössbauer spectroscopy reveal different degrees of partial occupancy of mixed-occupied sites by lithium. Electrochemical measurements show that the in situ formation of carbon improves capacity (90% of 1-electron theoretical capacity) through decreased charge-transfer resistance. © 2019 Elsevier B.V.",
publisher = "Elsevier",
journal = "Journal of Alloys and Compounds",
title = "Structural and electrochemical properties of the Li2FeP2O7/C composite prepared using soluble methylcellulose",
pages = "912-919",
volume = "786",
doi = "10.1016/j.jallcom.2019.01.392"
}
1

Structural and electrochemical properties of the Li2FeP2O7/C composite prepared using soluble methylcellulose

Jugović, Dragana; Mitrić, Miodrag; Milović, Miloš; Ivanovski, Valentin N.; Škapin, Srečo Davor; Dojčinović, Biljana; Uskoković, Dragan

(Elsevier, 2019)

TY  - JOUR
AU  - Jugović, Dragana
AU  - Mitrić, Miodrag
AU  - Milović, Miloš
AU  - Ivanovski, Valentin N.
AU  - Škapin, Srečo Davor
AU  - Dojčinović, Biljana
AU  - Uskoković, Dragan
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/4937
AB  - A new method involving the homogeneous dispersion of precursor compounds inside a methylcellulose matrix is used for the synthesis of a composite powder of Li 2 FeP 2 O 7 and carbon. The properties of carbon-containing and carbon-free powders are studied by X-ray powder diffraction (XRD) including Rietveld refinement, Mössbauer spectroscopy, Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), galvanostatic cycling, and electrochemical impedance spectroscopy (EIS). The structure of both powders is refined in a monoclinic framework (space group P2 1 /c). The structural refinement and Mössbauer spectroscopy reveal different degrees of partial occupancy of mixed-occupied sites by lithium. Electrochemical measurements show that the in situ formation of carbon improves capacity (90% of 1-electron theoretical capacity) through decreased charge-transfer resistance. © 2019 Elsevier B.V.
PB  - Elsevier
T2  - Journal of Alloys and Compounds
T1  - Structural and electrochemical properties of the Li2FeP2O7/C composite prepared using soluble methylcellulose
SP  - 912
EP  - 919
VL  - 786
DO  - 10.1016/j.jallcom.2019.01.392
ER  - 
@article{
author = "Jugović, Dragana and Mitrić, Miodrag and Milović, Miloš and Ivanovski, Valentin N. and Škapin, Srečo Davor and Dojčinović, Biljana and Uskoković, Dragan",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/4937",
abstract = "A new method involving the homogeneous dispersion of precursor compounds inside a methylcellulose matrix is used for the synthesis of a composite powder of Li 2 FeP 2 O 7 and carbon. The properties of carbon-containing and carbon-free powders are studied by X-ray powder diffraction (XRD) including Rietveld refinement, Mössbauer spectroscopy, Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), galvanostatic cycling, and electrochemical impedance spectroscopy (EIS). The structure of both powders is refined in a monoclinic framework (space group P2 1 /c). The structural refinement and Mössbauer spectroscopy reveal different degrees of partial occupancy of mixed-occupied sites by lithium. Electrochemical measurements show that the in situ formation of carbon improves capacity (90% of 1-electron theoretical capacity) through decreased charge-transfer resistance. © 2019 Elsevier B.V.",
publisher = "Elsevier",
journal = "Journal of Alloys and Compounds",
title = "Structural and electrochemical properties of the Li2FeP2O7/C composite prepared using soluble methylcellulose",
pages = "912-919",
volume = "786",
doi = "10.1016/j.jallcom.2019.01.392"
}
1

On the presence of antisite defect in monoclinic Li2FeSiO4 – A combined X-Ray diffraction and DFT study

Milović, Miloš; Vasić Anićijević, Dragana D.; Jugović, Dragana; Anićijević, Vladan J.; Veselinović, Ljiljana; Mitrić, Miodrag; Uskoković, Dragan

(Elsevier, 2019)

TY  - JOUR
AU  - Milović, Miloš
AU  - Vasić Anićijević, Dragana D.
AU  - Jugović, Dragana
AU  - Anićijević, Vladan J.
AU  - Veselinović, Ljiljana
AU  - Mitrić, Miodrag
AU  - Uskoković, Dragan
PY  - 2019
UR  - http://www.sciencedirect.com/science/article/pii/S1293255818308331
UR  - http://dais.sanu.ac.rs/123456789/4560
AB  - Li2FeSiO4 material, which was prepared by a solid state method, crystallized as monoclinic P21/n polymorph. X-ray diffraction analysis with Rietveld structural refinement indicates specific occupation of Li2 crystallographic site by Fe2+ cation in the amount of 6 atom percents as a result of an antisite defect formation. The exclusive occupation of Li2 position, out of two crystallographic positions Li1 and Li2, by Fe2+ was discussed in relation to the differences that exist in the crystal environment of these positions and further investigated by DFT calculations. It was confirmed that Fe-Li2 substitution is energetically favorable compared to both Fe-Li1 substitution and the pristine crystal. In addition, changes of lattice geometry upon antisite defect formation were analyzed, and the obtained result is discussed in light of various factors (electronic, geometrical and enthropic) that contribute to the overall stability of the system.
PB  - Elsevier
T2  - Solid State Sciences
T1  - On the presence of antisite defect in monoclinic Li2FeSiO4 – A combined X-Ray diffraction and DFT study
SP  - 81
EP  - 86
VL  - 87
DO  - 10.1016/j.solidstatesciences.2018.11.008
ER  - 
@article{
author = "Milović, Miloš and Vasić Anićijević, Dragana D. and Jugović, Dragana and Anićijević, Vladan J. and Veselinović, Ljiljana and Mitrić, Miodrag and Uskoković, Dragan",
year = "2019",
url = "http://www.sciencedirect.com/science/article/pii/S1293255818308331, http://dais.sanu.ac.rs/123456789/4560",
abstract = "Li2FeSiO4 material, which was prepared by a solid state method, crystallized as monoclinic P21/n polymorph. X-ray diffraction analysis with Rietveld structural refinement indicates specific occupation of Li2 crystallographic site by Fe2+ cation in the amount of 6 atom percents as a result of an antisite defect formation. The exclusive occupation of Li2 position, out of two crystallographic positions Li1 and Li2, by Fe2+ was discussed in relation to the differences that exist in the crystal environment of these positions and further investigated by DFT calculations. It was confirmed that Fe-Li2 substitution is energetically favorable compared to both Fe-Li1 substitution and the pristine crystal. In addition, changes of lattice geometry upon antisite defect formation were analyzed, and the obtained result is discussed in light of various factors (electronic, geometrical and enthropic) that contribute to the overall stability of the system.",
publisher = "Elsevier",
journal = "Solid State Sciences",
title = "On the presence of antisite defect in monoclinic Li2FeSiO4 – A combined X-Ray diffraction and DFT study",
pages = "81-86",
volume = "87",
doi = "10.1016/j.solidstatesciences.2018.11.008"
}
1

Synthesis of cathode composite powders from methylcellulose matrix: Li2FeSiO4/C, Li2FeP2O7/C and LiFePO4/C

Milović, Miloš; Jugović, Dragana; Mitrić, Miodrag; Kuzmanović, Maja; Vujković, Milica; Uskoković, Dragan

([s.l.] : [s.n.], 2019)

TY  - CONF
AU  - Milović, Miloš
AU  - Jugović, Dragana
AU  - Mitrić, Miodrag
AU  - Kuzmanović, Maja
AU  - Vujković, Milica
AU  - Uskoković, Dragan
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/7047
AB  - Since Padhi et al. reported the electrochemical properties of LiFePO4 in 1997 [1], polyanion cathode materials for lithium-ion batteries attract interest of researchers because of the added safety and higher voltage values in comparison to the oxide analogues with the same M2+/3+ redox pair. The higher safety and higher voltage come from strong covalent bonding within the polyanion units and, over the years, these inherent characteristics have promoted the investigation of different polyanion compounds. Among them, lithium transition-metal silicates, Li2MSiO4, and pyrophosphates, Li2MP2O7, additionally offer the possibility of extraction/ insertion two lithium ions per formula unit thus increasing theoretical capacity. However, unlike their oxide counterparts, polyanion cathodes suffer considerably from low conductivity (both ionic and electronic) which significantly limits their rate performance and therefore application in high power devices. To overcome this obstacle various strategies were developed like minimization of particle size, addition of conductive additives and/or ion doping. In this study, the approach that was used includes preparation of Li2FeSiO4/C, LiFePO4/C a nd L i2FeP2O7/C composites where carbon is obtained by pyrolytical degradation of methylcellulose and in situ during formation of polyanion active material on high temperatures. Methylcellulose, or methyl cellulose ether, is a water-soluble derivative of cellulose with an ability to gel upon heating and reversibly liquefy upon cooling due to the hydrophobic interaction between molecules containing methoxyl groups [2]. Thanks to this outstanding ability, the methylcellulose acts not only as a carbon source, but also as a dispersing agent that enables both the homogeneous deployment of the precursor compounds and the control of active material’ particle growth from the earliest stages of crystallization. This further allowed a significant shortening of high temperature treatment (to several minutes long) with additional decreases of particle agglomeration. Being both simple and inexpensive, the described method is also beneficial for commercial purposes. The electrochemical and microstructural properties of the obtained powders were examined and compared. Also, the opportunity is taken to discuss potential of a redox couple Fe2+/Fe3+ (Figure 1) in a relation to the crystal structure of a given polyanion cathode.
PB  - [s.l.] : [s.n.]
C3  - Abstracts/Proceedings / mESC-IS 2019 : The Fourth International Symposium on Materials for Energy Storage and Conversion, 7-11 September 2019, Akyaka –Muğla
T1  - Synthesis of cathode composite powders from methylcellulose matrix: Li2FeSiO4/C, Li2FeP2O7/C and LiFePO4/C
SP  - 42
EP  - 42
ER  - 
@conference{
author = "Milović, Miloš and Jugović, Dragana and Mitrić, Miodrag and Kuzmanović, Maja and Vujković, Milica and Uskoković, Dragan",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/7047",
abstract = "Since Padhi et al. reported the electrochemical properties of LiFePO4 in 1997 [1], polyanion cathode materials for lithium-ion batteries attract interest of researchers because of the added safety and higher voltage values in comparison to the oxide analogues with the same M2+/3+ redox pair. The higher safety and higher voltage come from strong covalent bonding within the polyanion units and, over the years, these inherent characteristics have promoted the investigation of different polyanion compounds. Among them, lithium transition-metal silicates, Li2MSiO4, and pyrophosphates, Li2MP2O7, additionally offer the possibility of extraction/ insertion two lithium ions per formula unit thus increasing theoretical capacity. However, unlike their oxide counterparts, polyanion cathodes suffer considerably from low conductivity (both ionic and electronic) which significantly limits their rate performance and therefore application in high power devices. To overcome this obstacle various strategies were developed like minimization of particle size, addition of conductive additives and/or ion doping. In this study, the approach that was used includes preparation of Li2FeSiO4/C, LiFePO4/C a nd L i2FeP2O7/C composites where carbon is obtained by pyrolytical degradation of methylcellulose and in situ during formation of polyanion active material on high temperatures. Methylcellulose, or methyl cellulose ether, is a water-soluble derivative of cellulose with an ability to gel upon heating and reversibly liquefy upon cooling due to the hydrophobic interaction between molecules containing methoxyl groups [2]. Thanks to this outstanding ability, the methylcellulose acts not only as a carbon source, but also as a dispersing agent that enables both the homogeneous deployment of the precursor compounds and the control of active material’ particle growth from the earliest stages of crystallization. This further allowed a significant shortening of high temperature treatment (to several minutes long) with additional decreases of particle agglomeration. Being both simple and inexpensive, the described method is also beneficial for commercial purposes. The electrochemical and microstructural properties of the obtained powders were examined and compared. Also, the opportunity is taken to discuss potential of a redox couple Fe2+/Fe3+ (Figure 1) in a relation to the crystal structure of a given polyanion cathode.",
publisher = "[s.l.] : [s.n.]",
journal = "Abstracts/Proceedings / mESC-IS 2019 : The Fourth International Symposium on Materials for Energy Storage and Conversion, 7-11 September 2019, Akyaka –Muğla",
title = "Synthesis of cathode composite powders from methylcellulose matrix: Li2FeSiO4/C, Li2FeP2O7/C and LiFePO4/C",
pages = "42-42"
}

Effects of fluorination on the structure, magnetic and electrochemical properties of the P2-type NaxCoO2 powder

Jugović, Dragana; Milović, Miloš; Popović, Maja; Kusigerski, Vladan; Škapin, Srečo Davor; Rakočević, Zlatko; Mitrić, Miodrag

(2019)

TY  - JOUR
AU  - Jugović, Dragana
AU  - Milović, Miloš
AU  - Popović, Maja
AU  - Kusigerski, Vladan
AU  - Škapin, Srečo Davor
AU  - Rakočević, Zlatko
AU  - Mitrić, Miodrag
PY  - 2019
UR  - http://www.sciencedirect.com/science/article/pii/S0925838818336375
UR  - http://dais.sanu.ac.rs/123456789/3978
AB  - The main goal of this research has been to investigate for the first time the effects of fluorination on the crystal structure, magnetic, and electrochemical properties of the P2-type NaxCoO2 powder. Sodium cobalt oxide with a P2-type structure is synthesized by a modified solid-state reaction consisting of alternating processes of rapid heating up to 750 °C and rapid cooling to the room temperature. The obtained powder is fluorinated using a gas-solid reaction with NH4HF2 as fluorinating agent. Fluorination causes a decrease of sodium content in the parent phase with the concurrent formation of the minor phases of Na2CO3 and NaF. The structure of NaxCoO2 in both powders is refined in P63/mmc space group. The results of the Rietveld refinement combined with the findings from the XPS measurements confirm the Na0.76CoO2 and Na0.44CoO1.96F0.04 stoichiometries for the pristine and fluorinated powders, respectively, which indicates that 4 at.% of fluorine ions per formula unit are incorporated in the structure. Preliminary electrochemical investigations have revealed an improved charge/discharge performance. The influence of fluorination on morphology and magnetic properties has also been examined.
T2  - Journal of Alloys and Compounds
T1  - Effects of fluorination on the structure, magnetic and electrochemical properties of the P2-type NaxCoO2 powder
SP  - 30
EP  - 37
VL  - 774
DO  - 10.1016/j.jallcom.2018.09.372
ER  - 
@article{
author = "Jugović, Dragana and Milović, Miloš and Popović, Maja and Kusigerski, Vladan and Škapin, Srečo Davor and Rakočević, Zlatko and Mitrić, Miodrag",
year = "2019",
url = "http://www.sciencedirect.com/science/article/pii/S0925838818336375, http://dais.sanu.ac.rs/123456789/3978",
abstract = "The main goal of this research has been to investigate for the first time the effects of fluorination on the crystal structure, magnetic, and electrochemical properties of the P2-type NaxCoO2 powder. Sodium cobalt oxide with a P2-type structure is synthesized by a modified solid-state reaction consisting of alternating processes of rapid heating up to 750 °C and rapid cooling to the room temperature. The obtained powder is fluorinated using a gas-solid reaction with NH4HF2 as fluorinating agent. Fluorination causes a decrease of sodium content in the parent phase with the concurrent formation of the minor phases of Na2CO3 and NaF. The structure of NaxCoO2 in both powders is refined in P63/mmc space group. The results of the Rietveld refinement combined with the findings from the XPS measurements confirm the Na0.76CoO2 and Na0.44CoO1.96F0.04 stoichiometries for the pristine and fluorinated powders, respectively, which indicates that 4 at.% of fluorine ions per formula unit are incorporated in the structure. Preliminary electrochemical investigations have revealed an improved charge/discharge performance. The influence of fluorination on morphology and magnetic properties has also been examined.",
journal = "Journal of Alloys and Compounds",
title = "Effects of fluorination on the structure, magnetic and electrochemical properties of the P2-type NaxCoO2 powder",
pages = "30-37",
volume = "774",
doi = "10.1016/j.jallcom.2018.09.372"
}
5
7
7

On the presence of antisite defect in monoclinic Li2FeSiO4 – A combined X-Ray diffraction and DFT study

Milović, Miloš; Vasić Anićijević, Dragana D.; Jugović, Dragana; Anićijević, Vladan J.; Veselinović, Ljiljana; Mitrić, Miodrag; Uskoković, Dragan

(Elsevier, 2019)

TY  - JOUR
AU  - Milović, Miloš
AU  - Vasić Anićijević, Dragana D.
AU  - Jugović, Dragana
AU  - Anićijević, Vladan J.
AU  - Veselinović, Ljiljana
AU  - Mitrić, Miodrag
AU  - Uskoković, Dragan
PY  - 2019
UR  - http://www.sciencedirect.com/science/article/pii/S1293255818308331
UR  - http://dais.sanu.ac.rs/123456789/4552
AB  - Li2FeSiO4 material, which was prepared by a solid state method, crystallized as monoclinic P21/n polymorph. X-ray diffraction analysis with Rietveld structural refinement indicates specific occupation of Li2 crystallographic site by Fe2+ cation in the amount of 6 atom percents as a result of an antisite defect formation. The exclusive occupation of Li2 position, out of two crystallographic positions Li1 and Li2, by Fe2+ was discussed in relation to the differences that exist in the crystal environment of these positions and further investigated by DFT calculations. It was confirmed that Fe-Li2 substitution is energetically favorable compared to both Fe-Li1 substitution and the pristine crystal. In addition, changes of lattice geometry upon antisite defect formation were analyzed, and the obtained result is discussed in light of various factors (electronic, geometrical and enthropic) that contribute to the overall stability of the system.
PB  - Elsevier
T2  - Solid State Sciences
T1  - On the presence of antisite defect in monoclinic Li2FeSiO4 – A combined X-Ray diffraction and DFT study
SP  - 81
EP  - 86
VL  - 87
DO  - 10.1016/j.solidstatesciences.2018.11.008
ER  - 
@article{
author = "Milović, Miloš and Vasić Anićijević, Dragana D. and Jugović, Dragana and Anićijević, Vladan J. and Veselinović, Ljiljana and Mitrić, Miodrag and Uskoković, Dragan",
year = "2019",
url = "http://www.sciencedirect.com/science/article/pii/S1293255818308331, http://dais.sanu.ac.rs/123456789/4552",
abstract = "Li2FeSiO4 material, which was prepared by a solid state method, crystallized as monoclinic P21/n polymorph. X-ray diffraction analysis with Rietveld structural refinement indicates specific occupation of Li2 crystallographic site by Fe2+ cation in the amount of 6 atom percents as a result of an antisite defect formation. The exclusive occupation of Li2 position, out of two crystallographic positions Li1 and Li2, by Fe2+ was discussed in relation to the differences that exist in the crystal environment of these positions and further investigated by DFT calculations. It was confirmed that Fe-Li2 substitution is energetically favorable compared to both Fe-Li1 substitution and the pristine crystal. In addition, changes of lattice geometry upon antisite defect formation were analyzed, and the obtained result is discussed in light of various factors (electronic, geometrical and enthropic) that contribute to the overall stability of the system.",
publisher = "Elsevier",
journal = "Solid State Sciences",
title = "On the presence of antisite defect in monoclinic Li2FeSiO4 – A combined X-Ray diffraction and DFT study",
pages = "81-86",
volume = "87",
doi = "10.1016/j.solidstatesciences.2018.11.008"
}
1

Electrochemical oxidation of maricite NaFePO4 in mild aqueous solutions as a way to boost its charge storage capacity

Petrović, Tamara; Milović, Miloš; Bajuk Bogdanović, Danica; Vujković, Milica

(Belgrade : Institute of Technical Sciences of SASA, 2019)

TY  - CONF
AU  - Petrović, Tamara
AU  - Milović, Miloš
AU  - Bajuk Bogdanović, Danica
AU  - Vujković, Milica
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/6971
AB  - Lithium has a low abundance in the Earth's crust, which in a few years will lead to difficult lithium production, and therefore difficult production of lithium-ion batteries. Sodium-ion batteries, on the other hand, have been proven to be a good replacement. The material obtained from iron combined with the phosphate and pyrophosphate compounds of sodium has attracted attention as a possible cathode material for sodium-ion batteries. NaFePO4 exists in two polymorphic structures (triphylite and maricite). Maricite NaFePO4 is a more thermodynamically stable structure than triphylite NaFePO4 but doesn’t have channels for Na+ movement and electrochemical performance of this structure is low. In comparison to maricite NaFePO4, triphylite NaFePO4 (structural analogue to LiFePO4) has one-dimensional channels for Na+-ions movement and better electrochemical activity but it is not stable and is difficult to synthesize. Herein, the maricite NaFePO4 can be obtained by sintering a polyanionic compound, Na4Fe3(PO4)2P2O7, at temperatures above 600 °C, as shown by XRD. Na4Fe3(PO4)2P2O7 is synthesized by the glycine-nitrate process after which it was sintered at temperatures above 500 °C. The glycine-nitrate process was found to catalyze the decomposition of the sintered Na4Fe3(PO4)2P2O7 to the NaFePO4 maricite. The electrochemical characterization of the sintered material, evaluated in aqueous NaNO3 and LiNO3 electrolyte by cyclic voltammetry, showed poor electrochemical activity of maricite NaFePO4. By exposing the sintered material to high anodic potentials, the electrochemical activity and specific capacity of the material were increased by 50% in case of NaNO3 and 80% in case of LiNO3 relative to the pristine with low activity. After electrochemical measurements, residual powder was characterized by FTIR and Raman spectroscopy. It was shown that high anodic polarization of the material tested in LiNO3 causes the formation of triphylite LiFePO4. Similarly, it is assumed that the electrochemical activity obtained by deep anodic polarization of the material in NaNO3 electrolyte originates from the formed triphylite NaFePO4. The obtained results open novel directions regarding the use of NaFePO4 in metal-ion rechargeable batteries.
PB  - Belgrade : Institute of Technical Sciences of SASA
C3  - Program and the Book of abstracts / Eighteenth Young Researchers' Conference Materials Sciences and Engineering, December 4-6, 2019, Belgrade, Serbia
T1  - Electrochemical oxidation of maricite NaFePO4 in mild aqueous solutions as a way to boost its charge storage capacity
SP  - 48
EP  - 48
ER  - 
@conference{
author = "Petrović, Tamara and Milović, Miloš and Bajuk Bogdanović, Danica and Vujković, Milica",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/6971",
abstract = "Lithium has a low abundance in the Earth's crust, which in a few years will lead to difficult lithium production, and therefore difficult production of lithium-ion batteries. Sodium-ion batteries, on the other hand, have been proven to be a good replacement. The material obtained from iron combined with the phosphate and pyrophosphate compounds of sodium has attracted attention as a possible cathode material for sodium-ion batteries. NaFePO4 exists in two polymorphic structures (triphylite and maricite). Maricite NaFePO4 is a more thermodynamically stable structure than triphylite NaFePO4 but doesn’t have channels for Na+ movement and electrochemical performance of this structure is low. In comparison to maricite NaFePO4, triphylite NaFePO4 (structural analogue to LiFePO4) has one-dimensional channels for Na+-ions movement and better electrochemical activity but it is not stable and is difficult to synthesize. Herein, the maricite NaFePO4 can be obtained by sintering a polyanionic compound, Na4Fe3(PO4)2P2O7, at temperatures above 600 °C, as shown by XRD. Na4Fe3(PO4)2P2O7 is synthesized by the glycine-nitrate process after which it was sintered at temperatures above 500 °C. The glycine-nitrate process was found to catalyze the decomposition of the sintered Na4Fe3(PO4)2P2O7 to the NaFePO4 maricite. The electrochemical characterization of the sintered material, evaluated in aqueous NaNO3 and LiNO3 electrolyte by cyclic voltammetry, showed poor electrochemical activity of maricite NaFePO4. By exposing the sintered material to high anodic potentials, the electrochemical activity and specific capacity of the material were increased by 50% in case of NaNO3 and 80% in case of LiNO3 relative to the pristine with low activity. After electrochemical measurements, residual powder was characterized by FTIR and Raman spectroscopy. It was shown that high anodic polarization of the material tested in LiNO3 causes the formation of triphylite LiFePO4. Similarly, it is assumed that the electrochemical activity obtained by deep anodic polarization of the material in NaNO3 electrolyte originates from the formed triphylite NaFePO4. The obtained results open novel directions regarding the use of NaFePO4 in metal-ion rechargeable batteries.",
publisher = "Belgrade : Institute of Technical Sciences of SASA",
journal = "Program and the Book of abstracts / Eighteenth Young Researchers' Conference Materials Sciences and Engineering, December 4-6, 2019, Belgrade, Serbia",
title = "Electrochemical oxidation of maricite NaFePO4 in mild aqueous solutions as a way to boost its charge storage capacity",
pages = "48-48"
}

The structure and electrochemical properties of fayalite Fe2SiO4

Jugović, Dragana; Mitrić, Miodrag; Milović, Miloš; Ivanovski, Valentin N.; Škapin, Srečo Davor; Uskoković, Dragan

(Belgrade : Materials Research Society of Serbia, 2019)

TY  - CONF
AU  - Jugović, Dragana
AU  - Mitrić, Miodrag
AU  - Milović, Miloš
AU  - Ivanovski, Valentin N.
AU  - Škapin, Srečo Davor
AU  - Uskoković, Dragan
PY  - 2019
UR  - http://dais.sanu.ac.rs/123456789/6674
AB  - Fayalite has been found various applications in many fields. Here is presented its use as anode material for lithium ion batteries. The syntheses of Fe2SiO4 and its composite with carbon are conducted through solid-state reaction at 850 °C under inert atmosphere of argon, using cheap and abundant precursors (Fe(NO3)3×9H2O and amorphous silica). Citric acid served as carbon source. The phase-purity of synthesized powders is checked by X-ray powder diffraction. The crystal structure of the powders is refined in orthorhombic Pbnm space group. Half-cell configuration, with lithium metal as counter electrode and fayalite as working electrode, is used for electrochemical measurements: galvanostatic cycling and electrochemical impedance spectroscopy.
PB  - Belgrade : Materials Research Society of Serbia
C3  - Programme and The Book of abstracts / Twenty-first Annual Conference YUCOMAT 2019 & Eleventh World Round Table Conference on Sintering WRTCS 2019, Herceg Novi, Montenegro, September 2-6, 2019
T1  - The structure and electrochemical properties of fayalite Fe2SiO4
SP  - 47
EP  - 47
ER  - 
@conference{
author = "Jugović, Dragana and Mitrić, Miodrag and Milović, Miloš and Ivanovski, Valentin N. and Škapin, Srečo Davor and Uskoković, Dragan",
year = "2019",
url = "http://dais.sanu.ac.rs/123456789/6674",
abstract = "Fayalite has been found various applications in many fields. Here is presented its use as anode material for lithium ion batteries. The syntheses of Fe2SiO4 and its composite with carbon are conducted through solid-state reaction at 850 °C under inert atmosphere of argon, using cheap and abundant precursors (Fe(NO3)3×9H2O and amorphous silica). Citric acid served as carbon source. The phase-purity of synthesized powders is checked by X-ray powder diffraction. The crystal structure of the powders is refined in orthorhombic Pbnm space group. Half-cell configuration, with lithium metal as counter electrode and fayalite as working electrode, is used for electrochemical measurements: galvanostatic cycling and electrochemical impedance spectroscopy.",
publisher = "Belgrade : Materials Research Society of Serbia",
journal = "Programme and The Book of abstracts / Twenty-first Annual Conference YUCOMAT 2019 & Eleventh World Round Table Conference on Sintering WRTCS 2019, Herceg Novi, Montenegro, September 2-6, 2019",
title = "The structure and electrochemical properties of fayalite Fe2SiO4",
pages = "47-47"
}

Effects of fluorination on the structure, magnetic and electrochemical properties of the P2-type NaxCoO2 powder

Jugović, Dragana; Milović, Miloš; Popović, Maja; Kusigerski, Vladan; Škapin, Srečo Davor; Rakočević, Zlatko; Mitrić, Miodrag

(2019)

TY  - JOUR
AU  - Jugović, Dragana
AU  - Milović, Miloš
AU  - Popović, Maja
AU  - Kusigerski, Vladan
AU  - Škapin, Srečo Davor
AU  - Rakočević, Zlatko
AU  - Mitrić, Miodrag
PY  - 2019
UR  - http://www.sciencedirect.com/science/article/pii/S0925838818336375
UR  - http://dais.sanu.ac.rs/123456789/3980
AB  - The main goal of this research has been to investigate for the first time the effects of fluorination on the crystal structure, magnetic, and electrochemical properties of the P2-type NaxCoO2 powder. Sodium cobalt oxide with a P2-type structure is synthesized by a modified solid-state reaction consisting of alternating processes of rapid heating up to 750 °C and rapid cooling to the room temperature. The obtained powder is fluorinated using a gas-solid reaction with NH4HF2 as fluorinating agent. Fluorination causes a decrease of sodium content in the parent phase with the concurrent formation of the minor phases of Na2CO3 and NaF. The structure of NaxCoO2 in both powders is refined in P63/mmc space group. The results of the Rietveld refinement combined with the findings from the XPS measurements confirm the Na0.76CoO2 and Na0.44CoO1.96F0.04 stoichiometries for the pristine and fluorinated powders, respectively, which indicates that 4 at.% of fluorine ions per formula unit are incorporated in the structure. Preliminary electrochemical investigations have revealed an improved charge/discharge performance. The influence of fluorination on morphology and magnetic properties has also been examined.
T2  - Journal of Alloys and Compounds
T1  - Effects of fluorination on the structure, magnetic and electrochemical properties of the P2-type NaxCoO2 powder
SP  - 30
EP  - 37
VL  - 774
DO  - 10.1016/j.jallcom.2018.09.372
ER  - 
@article{
author = "Jugović, Dragana and Milović, Miloš and Popović, Maja and Kusigerski, Vladan and Škapin, Srečo Davor and Rakočević, Zlatko and Mitrić, Miodrag",
year = "2019",
url = "http://www.sciencedirect.com/science/article/pii/S0925838818336375, http://dais.sanu.ac.rs/123456789/3980",
abstract = "The main goal of this research has been to investigate for the first time the effects of fluorination on the crystal structure, magnetic, and electrochemical properties of the P2-type NaxCoO2 powder. Sodium cobalt oxide with a P2-type structure is synthesized by a modified solid-state reaction consisting of alternating processes of rapid heating up to 750 °C and rapid cooling to the room temperature. The obtained powder is fluorinated using a gas-solid reaction with NH4HF2 as fluorinating agent. Fluorination causes a decrease of sodium content in the parent phase with the concurrent formation of the minor phases of Na2CO3 and NaF. The structure of NaxCoO2 in both powders is refined in P63/mmc space group. The results of the Rietveld refinement combined with the findings from the XPS measurements confirm the Na0.76CoO2 and Na0.44CoO1.96F0.04 stoichiometries for the pristine and fluorinated powders, respectively, which indicates that 4 at.% of fluorine ions per formula unit are incorporated in the structure. Preliminary electrochemical investigations have revealed an improved charge/discharge performance. The influence of fluorination on morphology and magnetic properties has also been examined.",
journal = "Journal of Alloys and Compounds",
title = "Effects of fluorination on the structure, magnetic and electrochemical properties of the P2-type NaxCoO2 powder",
pages = "30-37",
volume = "774",
doi = "10.1016/j.jallcom.2018.09.372"
}
5
7
7

Supplementary information for the article: Milović, M.D., Vasić Anićijević, D.D., Jugović, D., Anićijević, V.J., Veselinović, L., Mitrić, M., Uskoković, D., 2019. On the presence of antisite defect in monoclinic Li2FeSiO4 – A combined X-Ray diffraction and DFT study. Solid State Sciences 87, 81–86. https://doi.org/10.1016/j.solidstatesciences.2018.11.008

Milović, Miloš; Vasić Anićijević, Dragana D.; Jugović, Dragana; Anićijević, Vladan J.; Veselinović, Ljiljana; Mitrić, Miodrag; Uskoković, Dragan

(2019)

@misc{
author = "Milović, Miloš and Vasić Anićijević, Dragana D. and Jugović, Dragana and Anićijević, Vladan J. and Veselinović, Ljiljana and Mitrić, Miodrag and Uskoković, Dragan",
year = "2019",
url = "http://www.sciencedirect.com/science/article/pii/S1293255818308331, http://dais.sanu.ac.rs/123456789/5971",
journal = "Solid State Sciences",
title = "Supplementary information for the article: Milović, M.D., Vasić Anićijević, D.D., Jugović, D., Anićijević, V.J., Veselinović, L., Mitrić, M., Uskoković, D., 2019. On the presence of antisite defect in monoclinic Li2FeSiO4 – A combined X-Ray diffraction and DFT study. Solid State Sciences 87, 81–86. https://doi.org/10.1016/j.solidstatesciences.2018.11.008"
}

Structural and electrochemical study of lithium iron (II) pyrophosphate

Jugović, Dragana; Milović, Miloš; Mitrić, Miodrag; Ivanovski, Valentin N.; Škapin, Srečo Davor; Uskoković, Dragan

(Belgrade : Materials Research Society of Serbia, 2018)

TY  - CONF
AU  - Jugović, Dragana
AU  - Milović, Miloš
AU  - Mitrić, Miodrag
AU  - Ivanovski, Valentin N.
AU  - Škapin, Srečo Davor
AU  - Uskoković, Dragan
PY  - 2018
UR  - http://dais.sanu.ac.rs/123456789/3632
AB  - Lithium iron(II) pyrophosphate, Li2FeP2O7, attracts attention of researchers for application as a cathode material in rechargeable lithium batteries. Li2FeP2O7 has somewhat higher voltage than commercial LiFePO4 (3.5 and 3.4 V, respectively), thus enables higher energy density, and also provides the possibility of two-electron reaction during intercalation. Within this study, pristine Li2FeP2O7 and its composite with carbon Li2FeP2O7/C were synthesized, with the carbon being formed by the pyrolysis of organic precursor in situ during formation of Li2FeP2O7 at high temperature. The polymer of methylcellulose was used as carbon source because of its ability to reversibly, depending on temperature, dissolve or gel in water. The structural, electrical and electrochemical characteristics of prepared powders were investigated by means of X-ray diffraction analysis, Mossbauer spectroscopy, impedance spectroscopy and galvanostatic charge/discharge testing. The results imply that in situ formation of carbon alters lattice parameters, decreases crystallite size, and facilitates lithium ion intercalation/deintercalation processes. The Ministry of Education, Science and Technological Development of the Republic of Serbia provided financial support for this study under Grant No. III 45004
PB  - Belgrade : Materials Research Society of Serbia
C3  - Programme and The Book of Abstracts / Twentieth Annual Conference YUCOMAT 2018, Herceg Novi, September 3-7, 2018
T1  - Structural and electrochemical study of lithium iron (II) pyrophosphate
SP  - 68
EP  - 68
ER  - 
@conference{
author = "Jugović, Dragana and Milović, Miloš and Mitrić, Miodrag and Ivanovski, Valentin N. and Škapin, Srečo Davor and Uskoković, Dragan",
year = "2018",
url = "http://dais.sanu.ac.rs/123456789/3632",
abstract = "Lithium iron(II) pyrophosphate, Li2FeP2O7, attracts attention of researchers for application as a cathode material in rechargeable lithium batteries. Li2FeP2O7 has somewhat higher voltage than commercial LiFePO4 (3.5 and 3.4 V, respectively), thus enables higher energy density, and also provides the possibility of two-electron reaction during intercalation. Within this study, pristine Li2FeP2O7 and its composite with carbon Li2FeP2O7/C were synthesized, with the carbon being formed by the pyrolysis of organic precursor in situ during formation of Li2FeP2O7 at high temperature. The polymer of methylcellulose was used as carbon source because of its ability to reversibly, depending on temperature, dissolve or gel in water. The structural, electrical and electrochemical characteristics of prepared powders were investigated by means of X-ray diffraction analysis, Mossbauer spectroscopy, impedance spectroscopy and galvanostatic charge/discharge testing. The results imply that in situ formation of carbon alters lattice parameters, decreases crystallite size, and facilitates lithium ion intercalation/deintercalation processes. The Ministry of Education, Science and Technological Development of the Republic of Serbia provided financial support for this study under Grant No. III 45004",
publisher = "Belgrade : Materials Research Society of Serbia",
journal = "Programme and The Book of Abstracts / Twentieth Annual Conference YUCOMAT 2018, Herceg Novi, September 3-7, 2018",
title = "Structural and electrochemical study of lithium iron (II) pyrophosphate",
pages = "68-68"
}

Fluorination of sodium cobalt oxide: effects on structure and electrochemical performance

Milović, Miloš; Jugović, Dragana; Mitrić, Miodrag; Popović, Maja; Rakočević, Zlatko; Uskoković, Dragan

(Belgrade : Vinča Institute of Nuclear Sciences, University of Belgrade, 2018)

TY  - CONF
AU  - Milović, Miloš
AU  - Jugović, Dragana
AU  - Mitrić, Miodrag
AU  - Popović, Maja
AU  - Rakočević, Zlatko
AU  - Uskoković, Dragan
PY  - 2018
UR  - http://dais.sanu.ac.rs/123456789/4572
AB  - Within this research the possibility of fluorine doping of the P2 type NaxCo02 powder was examined. As fluorine substitution already proved successful in improving cathode performance of layered lithium-based counterparts, the effects of fluorination on structure and electrochenlical properties ofP2 NaxCo02 were investigated and discussed.
PB  - Belgrade : Vinča Institute of Nuclear Sciences, University of Belgrade
PB  - Belgrade : Hydrogen Economy Initiative Serbia
C3  - Program and the Book of Abstracts / 3rd International Symposium on Materials for Energy Storage and Conversion - mESC-IS 2018
T1  - Fluorination of sodium cobalt oxide: effects on structure and electrochemical performance
SP  - 98
EP  - 98
ER  - 
@conference{
author = "Milović, Miloš and Jugović, Dragana and Mitrić, Miodrag and Popović, Maja and Rakočević, Zlatko and Uskoković, Dragan",
year = "2018",
url = "http://dais.sanu.ac.rs/123456789/4572",
abstract = "Within this research the possibility of fluorine doping of the P2 type NaxCo02 powder was examined. As fluorine substitution already proved successful in improving cathode performance of layered lithium-based counterparts, the effects of fluorination on structure and electrochenlical properties ofP2 NaxCo02 were investigated and discussed.",
publisher = "Belgrade : Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade : Hydrogen Economy Initiative Serbia",
journal = "Program and the Book of Abstracts / 3rd International Symposium on Materials for Energy Storage and Conversion - mESC-IS 2018",
title = "Fluorination of sodium cobalt oxide: effects on structure and electrochemical performance",
pages = "98-98"
}

Structural properties and antisite defect formation in monoclinic Li2FeSiO4 – a DFT aspect

Vasić Anićijević, Dragana D.; Anićijević, Vladan J.; Milović, Miloš

(Belgrade : Institute of Technical Sciences of SASA, 2018)

TY  - CONF
AU  - Vasić Anićijević, Dragana D.
AU  - Anićijević, Vladan J.
AU  - Milović, Miloš
PY  - 2018
UR  - http://dais.sanu.ac.rs/123456789/4719
AB  - Properties of monoclinic Li2FeSiO4, which is a prominent candidate for future use as a cathode in lithium ion batteries, have been investigated by DFT+U method, using GGAPBE approximation, plane wave basis set and periodic boundary conditions. All calculations were performed in an antiferromagnetic state, which has been found to be energetically slightly more stable than ferromagnetic. Optimized lattice parameters and atomic coordinates have been compared to the literature data in order to verify the model. In addition, a particular attention was paid to the possibility of the formation of an antisite defect, which was introduced as the interchange between Fe and Li ions at both Li1 and Li2 crystallographic positions. The concentration of defect was varied from 0 to 25 molar per cent. Changes of structural, energetic, and magnetic properties of monoclinic Li2FeSiO4 upon increase of Li1-Fe and Li2-Fe antisite defect concentration have been analyzed and discussed in light of available experimental results.
PB  - Belgrade : Institute of Technical Sciences of SASA
C3  - Program and the Book of Abstracts / Seventeenth Young Researchers' Conference Materials Sciences and Engineering, December 5-7, 2018, Belgrade, Serbia
T1  - Structural properties and antisite defect formation in monoclinic Li2FeSiO4 – a DFT aspect
SP  - 25
EP  - 25
ER  - 
@conference{
author = "Vasić Anićijević, Dragana D. and Anićijević, Vladan J. and Milović, Miloš",
year = "2018",
url = "http://dais.sanu.ac.rs/123456789/4719",
abstract = "Properties of monoclinic Li2FeSiO4, which is a prominent candidate for future use as a cathode in lithium ion batteries, have been investigated by DFT+U method, using GGAPBE approximation, plane wave basis set and periodic boundary conditions. All calculations were performed in an antiferromagnetic state, which has been found to be energetically slightly more stable than ferromagnetic. Optimized lattice parameters and atomic coordinates have been compared to the literature data in order to verify the model. In addition, a particular attention was paid to the possibility of the formation of an antisite defect, which was introduced as the interchange between Fe and Li ions at both Li1 and Li2 crystallographic positions. The concentration of defect was varied from 0 to 25 molar per cent. Changes of structural, energetic, and magnetic properties of monoclinic Li2FeSiO4 upon increase of Li1-Fe and Li2-Fe antisite defect concentration have been analyzed and discussed in light of available experimental results.",
publisher = "Belgrade : Institute of Technical Sciences of SASA",
journal = "Program and the Book of Abstracts / Seventeenth Young Researchers' Conference Materials Sciences and Engineering, December 5-7, 2018, Belgrade, Serbia",
title = "Structural properties and antisite defect formation in monoclinic Li2FeSiO4 – a DFT aspect",
pages = "25-25"
}

Synthesis and characterization of Li2FeP2O7 cathode material

Jugović, Dragana; Milović, Miloš; Mitrić, Miodrag; Cvjetićanin, Nikola; Škapin, Srečo Davor; Uskoković, Dragan

(Belgrade : Materials Research Society of Serbia, 2017)

TY  - CONF
AU  - Jugović, Dragana
AU  - Milović, Miloš
AU  - Mitrić, Miodrag
AU  - Cvjetićanin, Nikola
AU  - Škapin, Srečo Davor
AU  - Uskoković, Dragan
PY  - 2017
UR  - http://dais.sanu.ac.rs/123456789/15439
AB  - The search for alternative cathode materials for Li-ion batteries has recently emerged Li2FeP2O7 pyrophosphate as a new potential competitor for LiFePO4 material. It has a possibility to offer good rate capability, lithium ion diffusivity and volumetric energy density, and is a material of high safety and low raw materials cost. In addition, there is the probability of releasing the second Li-atom at a higher redox potential of 5.2 V, where the theoretical capacity would reach 220 mAhg−1. Optimized solid state reaction is used for the synthesis of pure Li2FeP2O7 powder and a composite Li2FeP2O7/C. The synthesized powders are characterized by X-ray powder diffraction, field emission scanning electron microscopy, FTIR spectroscopy, and galvanostatic charge/discharge cycling.
PB  - Belgrade : Materials Research Society of Serbia
C3  - Programme and The Book of Abstracts / Nineteenth Annual Conference YUCOMAT 2017, Herceg Novi, September 4-8, 2017
T1  - Synthesis and characterization of Li2FeP2O7 cathode material
SP  - 46
EP  - 46
ER  - 
@conference{
author = "Jugović, Dragana and Milović, Miloš and Mitrić, Miodrag and Cvjetićanin, Nikola and Škapin, Srečo Davor and Uskoković, Dragan",
year = "2017",
url = "http://dais.sanu.ac.rs/123456789/15439",
abstract = "The search for alternative cathode materials for Li-ion batteries has recently emerged Li2FeP2O7 pyrophosphate as a new potential competitor for LiFePO4 material. It has a possibility to offer good rate capability, lithium ion diffusivity and volumetric energy density, and is a material of high safety and low raw materials cost. In addition, there is the probability of releasing the second Li-atom at a higher redox potential of 5.2 V, where the theoretical capacity would reach 220 mAhg−1. Optimized solid state reaction is used for the synthesis of pure Li2FeP2O7 powder and a composite Li2FeP2O7/C. The synthesized powders are characterized by X-ray powder diffraction, field emission scanning electron microscopy, FTIR spectroscopy, and galvanostatic charge/discharge cycling.",
publisher = "Belgrade : Materials Research Society of Serbia",
journal = "Programme and The Book of Abstracts / Nineteenth Annual Conference YUCOMAT 2017, Herceg Novi, September 4-8, 2017",
title = "Synthesis and characterization of Li2FeP2O7 cathode material",
pages = "46-46"
}

The influence of fluorine doping on the structural and electrical properties of the LiFePO4 powder

Jugović, Dragana; Mitrić, Miodrag; Milović, Miloš; Cvjetićanin, Nikola; Jokić, Bojan; Umićević, Ana; Uskoković, Dragan

(Elsevier, 2017)

TY  - JOUR
AU  - Jugović, Dragana
AU  - Mitrić, Miodrag
AU  - Milović, Miloš
AU  - Cvjetićanin, Nikola
AU  - Jokić, Bojan
AU  - Umićević, Ana
AU  - Uskoković, Dragan
PY  - 2017
UR  - http://dais.sanu.ac.rs/123456789/15433
AB  - Low intrinsic electronic conductivity is the main disadvantage of LiFePO4 when used as a cathode material in lithium ion batteries. The paper offers experimental proofs of the theoretical prediction that fluorine doping of LiFePO4 can enhance its electrical conductivity. The LiFePO4 and fluorine-doped LiFePO4 olivine type, carbon-free powders are synthesized and examined. The crystal structure refinements in the Pnma space group reveal that doping with fluorine ions preserves the olivine structure, while reducing both the lattice parameters and the antisite defect, and increasing the crystallite size. A small amount of incorporated fluorine enhances the electrical conductivity from 4.6×10−7 S cm−1 to 2.3×10−6 S cm−1 and has a positive impact on the electrochemical performance. Several spectroscopy techniques (Mössbauer, FTIR, and Raman) reveal differences between the two powders and additionally support the findings of both the Rietveld refinement and the conductivity measurements.
PB  - Elsevier
T2  - Ceramics International
T1  - The influence of fluorine doping on the structural and electrical properties of the LiFePO4 powder
SP  - 3224
EP  - 3230
VL  - 43
IS  - 3
DO  - 10.1016/j.ceramint.2016.11.149
ER  - 
@article{
author = "Jugović, Dragana and Mitrić, Miodrag and Milović, Miloš and Cvjetićanin, Nikola and Jokić, Bojan and Umićević, Ana and Uskoković, Dragan",
year = "2017",
url = "http://dais.sanu.ac.rs/123456789/15433",
abstract = "Low intrinsic electronic conductivity is the main disadvantage of LiFePO4 when used as a cathode material in lithium ion batteries. The paper offers experimental proofs of the theoretical prediction that fluorine doping of LiFePO4 can enhance its electrical conductivity. The LiFePO4 and fluorine-doped LiFePO4 olivine type, carbon-free powders are synthesized and examined. The crystal structure refinements in the Pnma space group reveal that doping with fluorine ions preserves the olivine structure, while reducing both the lattice parameters and the antisite defect, and increasing the crystallite size. A small amount of incorporated fluorine enhances the electrical conductivity from 4.6×10−7 S cm−1 to 2.3×10−6 S cm−1 and has a positive impact on the electrochemical performance. Several spectroscopy techniques (Mössbauer, FTIR, and Raman) reveal differences between the two powders and additionally support the findings of both the Rietveld refinement and the conductivity measurements.",
publisher = "Elsevier",
journal = "Ceramics International",
title = "The influence of fluorine doping on the structural and electrical properties of the LiFePO4 powder",
pages = "3224-3230",
volume = "43",
number = "3",
doi = "10.1016/j.ceramint.2016.11.149"
}
5
5
9

Synthesis and structural properties of sodium cobalt oxide

Aleksić, Jelena; Jugović, Dragana; Milović, Miloš; Mitrić, Miodrag; Uskoković, Dragan

(Belgrade : Institute of Technical Sciences of SASA, 2017)

TY  - CONF
AU  - Aleksić, Jelena
AU  - Jugović, Dragana
AU  - Milović, Miloš
AU  - Mitrić, Miodrag
AU  - Uskoković, Dragan
PY  - 2017
UR  - http://dais.sanu.ac.rs/123456789/15449
AB  - Sodium transition-metal oxides with general formula NaxTMO2 (TM = Co, Mn, Ni, etc.) have attracted a lot of interest in the battery community due to low cost of sodium in contrast to lithium. Sodium cobalt oxide is the most attractive of them for cathode application because of its conductive, thermic and magnetic characteristics. In this study, sodium cobalt oxide, NaxCoO2 , was synthesized by simple method which involves solid state reaction in air, at temperature of 900 ºC; starting materials were Na2CO3 and Co3O4 in stoichiometric amounts. Additionally, fluorination of the synthesized sodium cobalt oxide was carried out in vacuum at 200ºC; NH4HF2 was used as a fluorine source. Then, structural and microstructural properties of the obtained powders were examined.
PB  - Belgrade : Institute of Technical Sciences of SASA
C3  - Program and the Book of Abstracts / Sixteenth Young Researchers' Conference Materials Sciences and Engineering, December 6-8, 2017, Belgrade, Serbia
T1  - Synthesis and structural properties of sodium cobalt oxide
SP  - 37
EP  - 37
ER  - 
@conference{
author = "Aleksić, Jelena and Jugović, Dragana and Milović, Miloš and Mitrić, Miodrag and Uskoković, Dragan",
year = "2017",
url = "http://dais.sanu.ac.rs/123456789/15449",
abstract = "Sodium transition-metal oxides with general formula NaxTMO2 (TM = Co, Mn, Ni, etc.) have attracted a lot of interest in the battery community due to low cost of sodium in contrast to lithium. Sodium cobalt oxide is the most attractive of them for cathode application because of its conductive, thermic and magnetic characteristics. In this study, sodium cobalt oxide, NaxCoO2 , was synthesized by simple method which involves solid state reaction in air, at temperature of 900 ºC; starting materials were Na2CO3 and Co3O4 in stoichiometric amounts. Additionally, fluorination of the synthesized sodium cobalt oxide was carried out in vacuum at 200ºC; NH4HF2 was used as a fluorine source. Then, structural and microstructural properties of the obtained powders were examined.",
publisher = "Belgrade : Institute of Technical Sciences of SASA",
journal = "Program and the Book of Abstracts / Sixteenth Young Researchers' Conference Materials Sciences and Engineering, December 6-8, 2017, Belgrade, Serbia",
title = "Synthesis and structural properties of sodium cobalt oxide",
pages = "37-37"
}

The influence of fluorine doping on the structural and electrical properties of the LiFePO4 powder

Jugović, Dragana; Mitrić, Miodrag; Milović, Miloš; Cvjetićanin, Nikola; Jokić, Bojan; Umićević, Ana; Uskoković, Dragan

(Elsevier, 2017)

TY  - JOUR
AU  - Jugović, Dragana
AU  - Mitrić, Miodrag
AU  - Milović, Miloš
AU  - Cvjetićanin, Nikola
AU  - Jokić, Bojan
AU  - Umićević, Ana
AU  - Uskoković, Dragan
PY  - 2017
UR  - http://dais.sanu.ac.rs/123456789/2352
AB  - Low intrinsic electronic conductivity is the main disadvantage of LiFePO4 when used as a cathode material in lithium ion batteries. The paper offers experimental proofs of the theoretical prediction that fluorine doping of LiFePO4 can enhance its electrical conductivity. The LiFePO4 and fluorine-doped LiFePO4 olivine type, carbon-free powders are synthesized and examined. The crystal structure refinements in the Pnma space group reveal that doping with fluorine ions preserves the olivine structure, while reducing both the lattice parameters and the antisite defect, and increasing the crystallite size. A small amount of incorporated fluorine enhances the electrical conductivity from 4.6×10−7 S cm−1 to 2.3×10−6 S cm−1 and has a positive impact on the electrochemical performance. Several spectroscopy techniques (Mössbauer, FTIR, and Raman) reveal differences between the two powders and additionally support the findings of both the Rietveld refinement and the conductivity measurements.
PB  - Elsevier
T2  - Ceramics International
T1  - The influence of fluorine doping on the structural and electrical properties of the LiFePO4 powder
SP  - 3224
EP  - 3230
VL  - 43
IS  - 3
DO  - 10.1016/j.ceramint.2016.11.149
ER  - 
@article{
author = "Jugović, Dragana and Mitrić, Miodrag and Milović, Miloš and Cvjetićanin, Nikola and Jokić, Bojan and Umićević, Ana and Uskoković, Dragan",
year = "2017",
url = "http://dais.sanu.ac.rs/123456789/2352",
abstract = "Low intrinsic electronic conductivity is the main disadvantage of LiFePO4 when used as a cathode material in lithium ion batteries. The paper offers experimental proofs of the theoretical prediction that fluorine doping of LiFePO4 can enhance its electrical conductivity. The LiFePO4 and fluorine-doped LiFePO4 olivine type, carbon-free powders are synthesized and examined. The crystal structure refinements in the Pnma space group reveal that doping with fluorine ions preserves the olivine structure, while reducing both the lattice parameters and the antisite defect, and increasing the crystallite size. A small amount of incorporated fluorine enhances the electrical conductivity from 4.6×10−7 S cm−1 to 2.3×10−6 S cm−1 and has a positive impact on the electrochemical performance. Several spectroscopy techniques (Mössbauer, FTIR, and Raman) reveal differences between the two powders and additionally support the findings of both the Rietveld refinement and the conductivity measurements.",
publisher = "Elsevier",
journal = "Ceramics International",
title = "The influence of fluorine doping on the structural and electrical properties of the LiFePO4 powder",
pages = "3224-3230",
volume = "43",
number = "3",
doi = "10.1016/j.ceramint.2016.11.149"
}
5
5
9

Synthesis of Li2FeSiO4/C composite by sol-gel citric acid assisted method

Milović, Miloš; Jugović, Dragana; Mitrić, Miodrag; Stojković Simatović, Ivana; Škapin, Srečo Davor; Uskoković, Dragan

(Belgrade : Union of Engineers and Technicians of Serbia, 2016)

TY  - JOUR
AU  - Milović, Miloš
AU  - Jugović, Dragana
AU  - Mitrić, Miodrag
AU  - Stojković Simatović, Ivana
AU  - Škapin, Srečo Davor
AU  - Uskoković, Dragan
PY  - 2016
UR  - https://scindeks.ceon.rs/article.aspx?artid=0040-21761602181M
UR  - http://www.ncbi.nlm.nih.gov/pubmed/0040-21761602181M
UR  - http://dais.sanu.ac.rs/123456789/3360
AB  - This paper describes a procedure for the synthesis of the composite Li2FeSiO4/C by sol-gel method using citric acid as a chelating agent; the resulting gel precursor was thermally treated in a slightly reductive atmosphere of nitrogen with five percent of hydrogen, whereupon the in situ decomposition of citric acid to carbon occurs during formation of the Li2FeSiO4. The obtained nanocrystalline powder (with mean crystallite size of 27nm) crystallized in the P21/n space group as confirmed by X-ray diffractometry. The morphology of the powder was examined by scanning electron microscopy which revealed a wide distribution of particles by size, from 100 to 500 nm. The material has been tested as cathode in lithium-ion cell and exhibits high efficiency and almost theoretical capacity.
AB  - U ovom radu opisan je postupak sinteze kompozita Li2FeSiO4/C sol-gel metodom koristeći limunsku kiselinu kao helatni agens; dobijeni gel-prekursor termički je tretiran u blago redukcionoj atmosferi azota sa pet posto vodonika, pri čemu dolazi do in situ razlaganja limunske kiseline do ugljenika za vreme nastanka Li2FeSiO4. Dobijeni nanokristalniprah (srednje veličine kristalita 27 nm) kristalisao je u P21/n prostornoj grupi što je potvrđeno rendgenskom difraktometrijom. Morfologija praha ispitana je skanirajućom elektronskom mikroskopijom koja otkriva široku raspodelu čestica po veličini, od 100 - 500 nm. Materijal je ispitan kao katoda u litijum-jonskoj ćeliji i pokazuje visoku efikasnost i praktično teorijski kapacitet.
PB  - Belgrade : Union of Engineers and Technicians of Serbia
T2  - Tehnika
T1  - Synthesis of Li2FeSiO4/C composite by sol-gel citric acid assisted method
T1  - Sinteza kompozita Li2FeSiO4/C sol-gel metodom uz pomoć limunske kiseline
SP  - 181
EP  - 184
VL  - 71
IS  - 2
DO  - 10.5937/tehnika1602181M
ER  - 
@article{
author = "Milović, Miloš and Jugović, Dragana and Mitrić, Miodrag and Stojković Simatović, Ivana and Škapin, Srečo Davor and Uskoković, Dragan",
year = "2016",
url = "https://scindeks.ceon.rs/article.aspx?artid=0040-21761602181M, http://www.ncbi.nlm.nih.gov/pubmed/0040-21761602181M, http://dais.sanu.ac.rs/123456789/3360",
abstract = "This paper describes a procedure for the synthesis of the composite Li2FeSiO4/C by sol-gel method using citric acid as a chelating agent; the resulting gel precursor was thermally treated in a slightly reductive atmosphere of nitrogen with five percent of hydrogen, whereupon the in situ decomposition of citric acid to carbon occurs during formation of the Li2FeSiO4. The obtained nanocrystalline powder (with mean crystallite size of 27nm) crystallized in the P21/n space group as confirmed by X-ray diffractometry. The morphology of the powder was examined by scanning electron microscopy which revealed a wide distribution of particles by size, from 100 to 500 nm. The material has been tested as cathode in lithium-ion cell and exhibits high efficiency and almost theoretical capacity., U ovom radu opisan je postupak sinteze kompozita Li2FeSiO4/C sol-gel metodom koristeći limunsku kiselinu kao helatni agens; dobijeni gel-prekursor termički je tretiran u blago redukcionoj atmosferi azota sa pet posto vodonika, pri čemu dolazi do in situ razlaganja limunske kiseline do ugljenika za vreme nastanka Li2FeSiO4. Dobijeni nanokristalniprah (srednje veličine kristalita 27 nm) kristalisao je u P21/n prostornoj grupi što je potvrđeno rendgenskom difraktometrijom. Morfologija praha ispitana je skanirajućom elektronskom mikroskopijom koja otkriva široku raspodelu čestica po veličini, od 100 - 500 nm. Materijal je ispitan kao katoda u litijum-jonskoj ćeliji i pokazuje visoku efikasnost i praktično teorijski kapacitet.",
publisher = "Belgrade : Union of Engineers and Technicians of Serbia",
journal = "Tehnika",
title = "Synthesis of Li2FeSiO4/C composite by sol-gel citric acid assisted method, Sinteza kompozita Li2FeSiO4/C sol-gel metodom uz pomoć limunske kiseline",
pages = "181-184",
volume = "71",
number = "2",
doi = "10.5937/tehnika1602181M"
}

The use of methylcellulose for the synthesis of Li2FeSiO4/C composites

Milović, Miloš; Jugović, Dragana; Mitrić, Miodrag; Dominko, Robert; Stojković Simatović, Ivana; Jokić, Bojan; Uskoković, Dragan

(Springer, 2016)

TY  - JOUR
AU  - Milović, Miloš
AU  - Jugović, Dragana
AU  - Mitrić, Miodrag
AU  - Dominko, Robert
AU  - Stojković Simatović, Ivana
AU  - Jokić, Bojan
AU  - Uskoković, Dragan
PY  - 2016
UR  - http://dais.sanu.ac.rs/123456789/2318
AB  - The key parameters related to cathode materials for commercial use are a high specific capacity, good cycling stability, capacity retention at high current rates, as well as the simplicity of the synthesis process. This study presents a facile synthesis of a composite cathode material, Li2FeSiO4 with carbon, under extreme conditions: rapid heating, short dwell at 750 °C and subsequent quenching. The water-soluble polymer methylcellulose was used both as an excellent dispersing agent and a carbon source that pyrolytically degrades to carbon, thereby enabling the homogeneous deployment of the precursor compounds and the control of the Li2FeSiO4 particle growth from the earliest stage of processing. X-ray powder diffraction reveals the formation of Li2FeSiO4 nanocrystallites with a monoclinic structure in the P21/n space group (#14). The composite’s electrochemical performance as a cathode material in Li-ion batteries was examined. The influence of the amount of methylcellulose on the microstructural, morphological, conductive, and electrochemical properties of the obtained powders has been discussed. It has been shown that the overall electrochemical performance is improved with an increase of carbon content, through both the decrease of the mean particle diameter and the increase of electrical conductivity.
PB  - Springer
T2  - Cellulose
T1  - The use of methylcellulose for the synthesis of Li2FeSiO4/C composites
SP  - 239
EP  - 246
VL  - 23
IS  - 1
DO  - 10.1007/s10570-015-0806-9
ER  - 
@article{
author = "Milović, Miloš and Jugović, Dragana and Mitrić, Miodrag and Dominko, Robert and Stojković Simatović, Ivana and Jokić, Bojan and Uskoković, Dragan",
year = "2016",
url = "http://dais.sanu.ac.rs/123456789/2318",
abstract = "The key parameters related to cathode materials for commercial use are a high specific capacity, good cycling stability, capacity retention at high current rates, as well as the simplicity of the synthesis process. This study presents a facile synthesis of a composite cathode material, Li2FeSiO4 with carbon, under extreme conditions: rapid heating, short dwell at 750 °C and subsequent quenching. The water-soluble polymer methylcellulose was used both as an excellent dispersing agent and a carbon source that pyrolytically degrades to carbon, thereby enabling the homogeneous deployment of the precursor compounds and the control of the Li2FeSiO4 particle growth from the earliest stage of processing. X-ray powder diffraction reveals the formation of Li2FeSiO4 nanocrystallites with a monoclinic structure in the P21/n space group (#14). The composite’s electrochemical performance as a cathode material in Li-ion batteries was examined. The influence of the amount of methylcellulose on the microstructural, morphological, conductive, and electrochemical properties of the obtained powders has been discussed. It has been shown that the overall electrochemical performance is improved with an increase of carbon content, through both the decrease of the mean particle diameter and the increase of electrical conductivity.",
publisher = "Springer",
journal = "Cellulose",
title = "The use of methylcellulose for the synthesis of Li2FeSiO4/C composites",
pages = "239-246",
volume = "23",
number = "1",
doi = "10.1007/s10570-015-0806-9"
}
2
3
3

Sinteza, strukturna i elektrohemijska svojstva LiFePO4 i Li2FeSiO4 kao katodnih materijala za litijum-jonske baterije

Milović, Miloš

(Belgrade : University of Belgrade, Faculty of Physical Chemistry, 2016)

@phdthesis{
author = "Milović, Miloš",
year = "2016",
url = "http://dais.sanu.ac.rs/123456789/815",
abstract = "Predmet istraživanja ove doktorske disertacije su litijum gvožđe(II) fosfat (LiFePO4) i litijum gvožđe(II) silikat (Li2FeSiO4), koji predstavljaju novu generaciju polianjonskih interkalarnih katodnih materijala za litijum-jonske baterije. Cilj istraživanja je sinteza LiFePO4 i Li2FeSiO4 različitim metodama, kao i ispitivanje njihovih strukturnih i elektrohemijskih svojstava. U cilju unapređenja katodnih svojstava ova dva materijala, koja su ograničena njihovim svojstvenim jonsko-elektronskim transportnim osobinama, prahovi LiFePO4 i Li2FeSiO4 su modifikovani korišćenjem različitih načina sinteze putem formiranja in situ kompozita sa ugljenikom, regulacijom veličine zrna ili anjonskim dopiranjem korišćenjem jona fluora F- kao dopanta.
Metodom precipitacije i naknadnim odgrevanjem na 700°C u inertnoj, blago redukcionoj atmosferi sintetisani su prahovi čistog LiFePO4, zatim LiFePO4 dopiranog fluorom, kao i kompozita fluorom dopiranog LiFePO4 i ugljenika, gde je LiF korišćen je kao izvor fluora, a stearinska kiselina kao izvor ugljenika. Kompozit LiFePO4 i ugljenika (LiFePO4/C) je sintetisan originalnim metodom kratkog odgrevanja (5-10 min) prekursora u celuloznoj matrici, u istim uslovima tempe-rature i atmosfere, i naknadnim naglim hlađenjem. Prah Li2FeSiO4 sintetisan je reakcijom u čvrstom stanju na 750°C takođe u inertnoj, blago redukcionoj atmosferi. Kompozit Li2FeSiO4 i ugljenika (Li2FeSiO4/C) je sintetisan metodom kratkog odgrevanja (5-10 min) prekursora u metilceluloznoj matrici, u istim uslovima temperature i atmosfere, i naknadnim kvenčovanjem. Dobijeni prahovi su ispitivani rendgenostrukturnom analizom, termogravimetrijskom analizom, merenjem raspodele veličine zrna, merenjem specifične električne provodljivosti, elektronskom mikroskopijom, mesbauerovom spektroskopijom i galvanostatskim merenjem.
Utvrđeno je da se fluor ugrađuje u rešetku olivina u iznosu od 2 atom% isključivo na O2 mestu kiseonika što za posledicu ima smanjenu zapreminu jedinične ćelije i stabilizaciju strukture uz smanjenu defektnost, a povećanu kristaliničnost; ugradnja fluora nema bitnijeg uticaja na morfološke karakteristike praha; specifična električna provodljivost fluorom dopiranog LiFePO4 povećana je pet puta (oko pola reda veličine) u odnosu na čist LiFePO4; duži naponski platoi i veći specifični kapaciteti na svim brzinama punjenja i pražnjenja ukazuju na „dublju“ interkalaciju litijuma u olivinu dopiranom fluorom; katodna svojstva su dalje unapređena u kompozitu fluorom dopiranog LiFePO4/C zahvaljujući in situ dobijenom provodnom sloju ugljenika (5 tež%) koji oblaže čestice aktivnog materijala sprečavajući njihovu aglomeraciju i ukrupnjavanje. Kako bi se rast čestica dodatno ograničio ispitana je sinteza LiFePO4/C kompozita metodom kratkotrajnog termičkog tretmana prilikom čega je dobijena nanokristalna faza LiFePO4 (sred. veličine kristalita 35 nm) uz prisustvo minimalne količine defekata („antisite“, 2 at%) kao i amorfna faza C (40 tež%); dobijeni prah ostvaruje praktično teorijski kapacitet uz sjajnu reverzibilnost tokom 150 testiranih ciklusa.
Ispitivanjem čistog Li2FeSiO4 i kompozita Li2FeSiO4/C izvedeni su sledeći zaključci: P21/n struktura Li2FeSiO4 podložna je nastanku „antisite“ defekta, i to isključivo na Li2 mestu kao rezultat međukatjonske elektrostatičke interakcije; na osnovu prostorne distribucije vrednosti sume valence veza litijuma izračunata je 3D mapa mogućih putanja litijumovog jona u okviru P21/n rešetke i utvrđeno da je transport litijuma dvodimenzionalan po ravnima (101); tokom cikliranja su zapažene promene strukture koje ukazuju na neuređenu Pmnb fazu; katodna svojstva unapređena su kod kompozita sa ugljenikom i utvrđeno je da sadržaj ugljenika bitno utiče na veličinu kristalita, ukupnu kristaliničnost, veličinu čestica i provodljivost kompozita, ali kod većih sadržaja ugljenika dalje poboljšanje katodnih karakteristika izostaje., The research topic of this doctoral thesis are lithium iron(II) phosphate (LiFePO4) and lithium iron(II) silicate (Li2FeSiO4), representatives of the new generation of intercalation polyanionic cathode materials for lithium-ion batteries and alternatives to the old materials based on oxides. The aim of the research is the synthesis of LiFePO4 and Li2FeSiO4 with different methods, as well as the investigation of their structural and electrochemical properties. In order to improve cathode performance of these two materials, which is limited with their intrinsic ionic-electronic transport properties, the powders of Li2FeSiO4 and LiFePO4 were modified using different methods of synthesis by creating in situ composites with carbon, by grain size control or by anion doping using fluorine ion F- as dopant.
Using precipitation method and subsequent annealing at 700°C in an inert, slightly reductive atmosphere, powders of a pristine LiFePO4, fluorine doped LiFePO4 and fluorine doped LiFePO4/carbon composite, wherein LiF is used as the fluorine source and stearic acid as the carbon source. The composite of the undoped LiFePO4 and carbon (LiFePO4/C) was synthesized by the original method of a short termic treatment (5-10 min) of a precursor in the cellulose matrix under the same temperature and atmosphere conditions, and subsequent quenching. Li2FeSiO4 powder was synthesized by solid state reaction at 750°C also in an inert, slightly reductive atmosphere. The composite of the Li2FeSiO4 and a carbon (Li2FeSiO4/C) was synthesized by the short thermic treatment (5-10 min) of a precursor in methylcellulose matrix, under the same temperature and atmosphere conditions and subsequent quenching. The obtained powders were examined by X-ray diffraction (XRD), thermogravimetric analysis (TGA), particle size analysis (PSA), specific electrical conductivity measurements, electron microscopy (EM), Mössbauer spectroscopy and galvanostatic testing.
It was found that the fluorine is incorporated into the lattice of olivine LiFePO4 in the amount of 2 atom% exclusively on O2 sites of oxygen, resulting in a reduced unit cell volume and the structure stabilization (reduced concentration of defects and increased crystallinity); incorporation of a fluorine has no significant impact on the morphological characteristics of the powder; specific electric conductivity of the fluorine doped LiFePO4 is increased five times (about one order of magnitude) when compared to pure LiFePO4; longer voltage plateaus and higher specific capacity at all current densities indicate "deeper" intercalation of lithium in the fluorine doped olivine; the cathode performance was further enhanced in the composite of fluorine doped LiFePO4/C thanks to the in situ obtained conductive layer of carbon coating (5 wt%), which prevents agglomeration and particle growth. In order to further restrict grain growth, method of a short thermic treatment was employed for the synthesis of LiFePO4/C composite resulting in a nanocrystalline phase of LiFePO4 (average crystallite size of 35 nm) with minimal presence of defects (antisite, 2 atom%) and amorphous phase of carbon (40 wt%); as prepared powder achieves nearly theoretical capacity and reversible cycling during 150 tested cycles.
The investigation of pristine Li2FeSiO4 and composite Li2FeSiO4/C resulted in following conclusions: P21/n structure of Li2FeSiO4 is prone to the antisite defect exclusively on Li2 sites of lithium as a consequence of electrostatic interactions between cations; using spatial distributions of lithium bond valence sum within P21/n structure, the map of possible lithium diffusion pathways was calculated on 3D grid and it was found that lithium transport is two dimensional in (101) planes; during cycling structural changes were observed leading, according to preliminary estimates, to the disordered Pmnb phase; cathode performance has been improved by preparing in situ composites with carbon and it was found that the content of carbon significantly affects the crystallite size, total crystallinity, grain size and conductivity of the composite, but if the carbon content is too high further improvement of cathode characteristics is absent (saturation occurs).",
publisher = "Belgrade : University of Belgrade, Faculty of Physical Chemistry",
title = "Sinteza, strukturna i elektrohemijska svojstva LiFePO4 i Li2FeSiO4 kao katodnih materijala za litijum-jonske baterije"
}

The influence of fluorine doping on the structural and the electrical properties of LiFePO4 powder

Jugović, Dragana; Mitrić, Miodrag; Milović, Miloš; Cvjetićanin, Nikola; Jokić, Bojan; Umićević, Ana; Uskoković, Dragan

(Belgrade : Materials Research Society of Serbia, 2016)

TY  - CONF
AU  - Jugović, Dragana
AU  - Mitrić, Miodrag
AU  - Milović, Miloš
AU  - Cvjetićanin, Nikola
AU  - Jokić, Bojan
AU  - Umićević, Ana
AU  - Uskoković, Dragan
PY  - 2016
UR  - http://dais.sanu.ac.rs/123456789/898
AB  - Low intrinsic electronic conductivity is the main weakness of LiFePO4 for the use as cathode material in lithium ion batteries. Here is presented an experimental proof of the theoretical prediction that fluorine doping of LiFePO4 can enhance its electrical conductivity. LiFePO4 and fluorine-doped LiFePO4 olivine type, carbon-free powders are synthesized and examined. Crystal structure refinements in the space group Pnma reveal that doping with fluorine ions preserves olivine structure with the reduction of both the lattice parameters and the antisite defect, and an increase of a crystallite size. A small amount of incorporated fluorine enhances electrical conductivity from 4.6 × 10-7 Scm-1 to 2.3 × 10-6 Scm-1 and has positive impact on the electrochemical performances. Several spectroscopy techniques (Mössbauer, FTIR, and Raman) disclose differences between two powders and additionally support the findings of both the Rietveld refinement and the conductivity measurements.
PB  - Belgrade : Materials Research Society of Serbia
C3  - Programme and The Book of Abstracts / Eighteenth Annual Conference YUCOMAT 2016, Herceg Novi, September 5-10, 2016
T1  - The influence of fluorine doping on the structural and the electrical properties of LiFePO4 powder
SP  - 35
EP  - 35
ER  - 
@conference{
author = "Jugović, Dragana and Mitrić, Miodrag and Milović, Miloš and Cvjetićanin, Nikola and Jokić, Bojan and Umićević, Ana and Uskoković, Dragan",
year = "2016",
url = "http://dais.sanu.ac.rs/123456789/898",
abstract = "Low intrinsic electronic conductivity is the main weakness of LiFePO4 for the use as cathode material in lithium ion batteries. Here is presented an experimental proof of the theoretical prediction that fluorine doping of LiFePO4 can enhance its electrical conductivity. LiFePO4 and fluorine-doped LiFePO4 olivine type, carbon-free powders are synthesized and examined. Crystal structure refinements in the space group Pnma reveal that doping with fluorine ions preserves olivine structure with the reduction of both the lattice parameters and the antisite defect, and an increase of a crystallite size. A small amount of incorporated fluorine enhances electrical conductivity from 4.6 × 10-7 Scm-1 to 2.3 × 10-6 Scm-1 and has positive impact on the electrochemical performances. Several spectroscopy techniques (Mössbauer, FTIR, and Raman) disclose differences between two powders and additionally support the findings of both the Rietveld refinement and the conductivity measurements.",
publisher = "Belgrade : Materials Research Society of Serbia",
journal = "Programme and The Book of Abstracts / Eighteenth Annual Conference YUCOMAT 2016, Herceg Novi, September 5-10, 2016",
title = "The influence of fluorine doping on the structural and the electrical properties of LiFePO4 powder",
pages = "35-35"
}

Fluorine Doping of Layered NaxCoO2 Structure

Jugović, Dragana; Milović, Miloš; Mitrić, Miodrag; Cvjetićanin, Nikola; Avdeev, Maxim; Jokić, Bojan; Uskoković, Dragan

(Belgrade : Materials Research Society of Serbia, 2015)

TY  - CONF
AU  - Jugović, Dragana
AU  - Milović, Miloš
AU  - Mitrić, Miodrag
AU  - Cvjetićanin, Nikola
AU  - Avdeev, Maxim
AU  - Jokić, Bojan
AU  - Uskoković, Dragan
PY  - 2015
UR  - http://dais.sanu.ac.rs/123456789/827
AB  - The room temperature Na-ion secondary battery has been under focus lately due to its feasibility to compete against the already well-established Li-ion secondary battery. Transition metal oxides of general formula NaxMO2 have been investigated as potential cathode materials for sodium batteries. Layered NaxCoO2 is synthesized via solid-state method at 900 ºC in air atmosphere. Fluorine doping of the as-prepared powder is established by the use of ammonium hydrogen difluoride (NH4HF2) as a fluorinating agent. The fluorination takes place only at low temperature (200 ºC), while the treatment at higher temperatures (≥ 400 ºC) facilitates the formation of NaF. It is shown that various and controllable amounts of fluorine can be successfully incorporated into the structure. Finally, the effects of fluorine doping on both structural and electrochemical properties are examined.
PB  - Belgrade : Materials Research Society of Serbia
C3  - Programme and The Book of Abstracts / Seventeenth Annual Conference YUCOMAT 205, Herceg Novi, August 31– September 4, 2015
T1  - Fluorine Doping of Layered NaxCoO2 Structure
SP  - 12
EP  - 12
ER  - 
@conference{
author = "Jugović, Dragana and Milović, Miloš and Mitrić, Miodrag and Cvjetićanin, Nikola and Avdeev, Maxim and Jokić, Bojan and Uskoković, Dragan",
year = "2015",
url = "http://dais.sanu.ac.rs/123456789/827",
abstract = "The room temperature Na-ion secondary battery has been under focus lately due to its feasibility to compete against the already well-established Li-ion secondary battery. Transition metal oxides of general formula NaxMO2 have been investigated as potential cathode materials for sodium batteries. Layered NaxCoO2 is synthesized via solid-state method at 900 ºC in air atmosphere. Fluorine doping of the as-prepared powder is established by the use of ammonium hydrogen difluoride (NH4HF2) as a fluorinating agent. The fluorination takes place only at low temperature (200 ºC), while the treatment at higher temperatures (≥ 400 ºC) facilitates the formation of NaF. It is shown that various and controllable amounts of fluorine can be successfully incorporated into the structure. Finally, the effects of fluorine doping on both structural and electrochemical properties are examined.",
publisher = "Belgrade : Materials Research Society of Serbia",
journal = "Programme and The Book of Abstracts / Seventeenth Annual Conference YUCOMAT 205, Herceg Novi, August 31– September 4, 2015",
title = "Fluorine Doping of Layered NaxCoO2 Structure",
pages = "12-12"
}

Structural study of monoclinic Li2FeSiO4 by X-ray diffraction and Mössbauer spectroscopy

Jugović, Dragana; Milović, Miloš; Ivanovski, Valentin N.; Avdeev, Maxim; Dominko, Robert; Jokić, Bojan; Uskoković, Dragan

(2014)

TY  - JOUR
AU  - Jugović, Dragana
AU  - Milović, Miloš
AU  - Ivanovski, Valentin N.
AU  - Avdeev, Maxim
AU  - Dominko, Robert
AU  - Jokić, Bojan
AU  - Uskoković, Dragan
PY  - 2014
UR  - http://dais.sanu.ac.rs/123456789/755
AB  - A composite powder Li2FeSiO4/C is synthesized through a solid state reaction at 750 °C. The Rietveld crystal structure refinement is done in the monoclinic P21/n space group. It is found that the crystal structure is prone to “antisite” defect where small part of iron ion occupies exclusively Li(2) crystallographic position, of two different lithium tetrahedral positions (Li(1) and Li(2)). This finding is also confirmed by Mössbauer spectroscopy study: the sextet evidenced in the Mössbauer spectrum is assigned to the iron ions positioned at the Li(2) sites. A bond-valence energy landscape calculation is used to predict the conduction pathways of lithium ions. The calculations suggest that Li conductivity is two-dimensional in the (101) plane. Upon galvanostatic cyclings the structure starts to rearrange to inverse βII polymorph.
T2  - Journal of Power Sources
T1  - Structural study of monoclinic Li2FeSiO4 by X-ray diffraction and Mössbauer spectroscopy
SP  - 75
EP  - 80
VL  - 265
DO  - 10.1016/j.jpowsour.2014.04.121
ER  - 
@article{
author = "Jugović, Dragana and Milović, Miloš and Ivanovski, Valentin N. and Avdeev, Maxim and Dominko, Robert and Jokić, Bojan and Uskoković, Dragan",
year = "2014",
url = "http://dais.sanu.ac.rs/123456789/755",
abstract = "A composite powder Li2FeSiO4/C is synthesized through a solid state reaction at 750 °C. The Rietveld crystal structure refinement is done in the monoclinic P21/n space group. It is found that the crystal structure is prone to “antisite” defect where small part of iron ion occupies exclusively Li(2) crystallographic position, of two different lithium tetrahedral positions (Li(1) and Li(2)). This finding is also confirmed by Mössbauer spectroscopy study: the sextet evidenced in the Mössbauer spectrum is assigned to the iron ions positioned at the Li(2) sites. A bond-valence energy landscape calculation is used to predict the conduction pathways of lithium ions. The calculations suggest that Li conductivity is two-dimensional in the (101) plane. Upon galvanostatic cyclings the structure starts to rearrange to inverse βII polymorph.",
journal = "Journal of Power Sources",
title = "Structural study of monoclinic Li2FeSiO4 by X-ray diffraction and Mössbauer spectroscopy",
pages = "75-80",
volume = "265",
doi = "10.1016/j.jpowsour.2014.04.121"
}
9
11
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Li2FeSiO4 cathode material: the structure and electrochemical performances

Jugović, Dragana; Milović, Miloš; Mitrić, Miodrag; Ivanovski, Valentin N.; Avdeev, Maxim; Jokić, Bojan; Dominko, Robert; Uskoković, Dragan

(Belgrade : Materials Research Society of Serbia, 2014)

TY  - CONF
AU  - Jugović, Dragana
AU  - Milović, Miloš
AU  - Mitrić, Miodrag
AU  - Ivanovski, Valentin N.
AU  - Avdeev, Maxim
AU  - Jokić, Bojan
AU  - Dominko, Robert
AU  - Uskoković, Dragan
PY  - 2014
UR  - http://dais.sanu.ac.rs/123456789/590
AB  - Monoclinic Li2FeSiO4 that crystallizes in P21/n space group was investigated as a potential cathode material for lithium-ion batteries. A combined X-ray diffraction and Mössbauer spectroscopy study was used for the structural investigation. It was found that the crystal structure is prone to an “antisite” defect, the one in which the Fe ion and the Li ion exchange places. This finding was also confirmed by the Mössbauer spectroscopy. In order to obtain composites of Li2FeSiO4 and carbon, several synthesis techniques that use different carbon sources were involved. Electrochemical performances were investigated through galvanostatic charge/discharge tests. Discharge curve profile did not reflect a two-phase intercalation reaction (no obvious voltage plateau) due to the low conductivity at room temperature.
PB  - Belgrade : Materials Research Society of Serbia
C3  - The Sixteenth Annual Conference YUCOMAT 2014: Programme and the Book of Abstracts
T1  - Li2FeSiO4 cathode material: the structure and electrochemical performances
SP  - 6
EP  - 6
ER  - 
@conference{
author = "Jugović, Dragana and Milović, Miloš and Mitrić, Miodrag and Ivanovski, Valentin N. and Avdeev, Maxim and Jokić, Bojan and Dominko, Robert and Uskoković, Dragan",
year = "2014",
url = "http://dais.sanu.ac.rs/123456789/590",
abstract = "Monoclinic Li2FeSiO4 that crystallizes in P21/n space group was investigated as a potential cathode material for lithium-ion batteries. A combined X-ray diffraction and Mössbauer spectroscopy study was used for the structural investigation. It was found that the crystal structure is prone to an “antisite” defect, the one in which the Fe ion and the Li ion exchange places. This finding was also confirmed by the Mössbauer spectroscopy. In order to obtain composites of Li2FeSiO4 and carbon, several synthesis techniques that use different carbon sources were involved. Electrochemical performances were investigated through galvanostatic charge/discharge tests. Discharge curve profile did not reflect a two-phase intercalation reaction (no obvious voltage plateau) due to the low conductivity at room temperature.",
publisher = "Belgrade : Materials Research Society of Serbia",
journal = "The Sixteenth Annual Conference YUCOMAT 2014: Programme and the Book of Abstracts",
title = "Li2FeSiO4 cathode material: the structure and electrochemical performances",
pages = "6-6"
}