Elektrohemijski izvori energije sistema metal ׀ elektroprovodni polimer na bazi vodenih rastvora

Abstract

U ovom radu su ispitane mogućnosti primene polimera polianilina (PANI) i polipirola (pPu) kao katodnih materijala u kombinaciji sa anodama od Zn, Mg i Al za potencijalnu primenu u elektrohemijskim izvorima struje (EIE). PANI i PPu su polimerizaovani elektrohemijskim postulkom u rastvoru odgovarajučćeg monomera i HC1 i okarakterisan tehnikom ciklične voltametrije. Pokazano je da elektroda na bazi pPu, i ako poseduje dobre elektrohemijske karakteristike, nije pogodna za upotrebu u EIE usled intenzivne degradacije polimera. Rezultati ipitivanja elektrode na bazi PANI ukazali su na postojanje dve forme PANI (emeraldin i perningranilin), kao i na degradaciju PANI. Ispitan je uticaja rN vrednosti i različitih anjona na degradaciju PANI sa ciljem izbora pogodnog elektrolita za EIE i njegove dalje optimizacije. Izabran je elektrolit hlorid/citrat pri rN - 5 jer je u ovom rastvoru utvrđena smanjena korozija ispitivanih metala. Daljim ispitivanjima, pokazano je da je jedino Zn moguće koristiti u EIE. Ispitano je i optimizovano u realnim uslovima ponašanje elektroda od PANI i Zn u rastvoru hlorid/citrat. Utvrđeno je da je iskorišćenje struje no Zn oko 95% za struje veće od 5 mA cm-2, pa je u realnom sistemu, radna površina PANI elektrode bila pet puta veća. Dobijene su dobre naponske karakteristike tokom 20 ciklusa rada, a napon otvorenog kola je bio stabilin u toku deset dana i iznosio je oko 1.4 V. Utvrđeno je da je samopražnjenje ovog sisema oko 1.5 % dnevno, što je u skladu sa samopražnjenjem sistema sa polianilinskim elektrodama.

The possible application of polyaniline (PANI) and polypyrrole (pPy) as cathodic materials combined to Zn, Mg and Al as anodic materials in electrochemical power sources were investigated. Electrochemical polymerization of PANI and pPy was performed from HC1 solution containing suitable monomer while cyclic voltammetry technique was used for characterization. It was shown that, apart from its good electrochemical characteristics, pPy electrode was not suitable for use in electrochemical power sources, due to intensive degradation. It was observed that PANI excised in two different forms emeraldine and perningraniline salt and that degradation of PANI occurred as well. Influence of pH and various anions on degradation of PANI was investigated in order to choose electrolyte for electrochemical power sources and its optimization. It was shown that in chloride/citrate electrolyte at pH~5, because on this pH values is reduced corrosion of investigated metals. Further investigation was shown that only Zn can be used in electrochemical power sources. Behavior of the real system PANI and Zn electrode was investigated and optimized in chloride/citrate electrolyte. It was observed that current efficiency for Zn was about 95% for current grater than 5 mA cm-2, and because of that, in the real system working area of the PANI electrode was five times greater than Zn electrode. For such system, good voltage characteristics during working 20 cycles were obtained. The open circuit voltage of 1.4 V was stable during 10 days. It was observed that the self discharge of the system was about 1.5% per day, which is in accordance to the self discharge of systems with PANI electrode.