Electrical properties of electrochemically co-polymerized aniline and sulphanilic acid

Abstract

Electrochemical synthesis of poly(aniline-co-(sulfanilic acid)) was performed on a graphite electrode with constant current densities from an aqueous electrolyte containing 1.0 mol dm-3 H2SO4 and 0.25 mol dm-3 monomers with different ratios of aniline and sulfanilic acid. Optimal conditions for copolymerization were set to the current density of 0.75 mA cm-2 and the electrolyte containing 0.15 mol dm-3 aniline and 0.10 mol dm-3 sulfanilic acid. Electrochemical characterization of the poly(aniline-co-(sulfanilic acid)) electrode was performed using cyclic voltammetry and galvanostatic charge/discharge techniques. Electrical properties such as specific power and specific energy at different discharge currents were also determined. Based on the Ragon plot, it was observed that the poly(aniline-co-(sulfanilic acid)) electrode exhibited battery features at low discharge currents. In contrast, it was possible to achieve specific power of supercapacitors at high discharge currents. Moreover, after 4000 cycles of charge/discharge poly(aniline-co-(sulfanilic acid)), capacity retention exceeding 90 % was obtained.

Elektrohemijska kopolimerizacija anilina i sulfanilne kiseline ostvarena je u galvanostatskim uslovima različitim gustinama struje na grafitnoj elektrodi. Kao elektrolit korišćen je vodeni rastvor 1.0 mol dm-3 H2SO4 sa dodatkom 0.25 mol dm-3 monomera različitog odnosa anilina i sulfanilne kiseline. Izabrani su optimalni uslovi za sintezu u pogledu gustine struje polimerizacije od 0.75 mA cm-2 i sastava elektrolita koji je sadržavao 0.15 mol dm-3 anilina i 0.10 mol dm-3 sulfanilne kiseline. Za elektrohemijsku karakterizaciju elektrode na bazi kopolimera anilina i sulfanilne kiseline korišćene su tehnike ciklične voltametrije i snimanja hronopotenciometrijskih krivih punjenja/pražnjenja. Na osnovu krivih pražnjenja procenjene su električne karakteristike ove elektrode: specifična energija i specifična snaga. Na osnovu Ragonovog dijagrama pokazano je da elektroda na bazi kopolimera anilina i sulfanilne kiseline poseduje baterijska svojstva pri niskim strujama pražnjenja, dok se pri visokim strujama pražnjenja ponaša kao elektroda superkondenzatora. Takođe, ova elektroda je nakon 4000 ciklusa punjenja i pražnjenja zadržala preko 90 % početnog kapaciteta.