Electrochemical and physicochemical investigation of B(Pb)SCCO ceramics: potential applications in rechargeable Ni-Zn batteries

Electrochemical and physicochemical investigation of B(Pb)SCCO ceramics: potential applications in rechargeable Ni-Zn batteries

Poster

A. Stoyanova-Ivanova1, A. Vasev1, P. Lilov1, V. Mikli2
1G. Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia, Bulgaria
2Institute of Materials and Environmental Technology, Tallinn University of Technology, Estonia

Nickel-zinc alkaline batteries represent a potential cheaper alternative in the secondary battery market. Various metal oxide and hydroxide additives (Bi2O3, PbO, Ca(OH)2) have been investigated as a solution to problems such as changes in the Zn electrode shape and formation of zinc dendrites, surface passivation and hydrogen evolution, and thus reducing the battery life. Other studies have shown that Bi2O3 and CuO can be reduced to the metals under alkaline conditions similar to the Ni-Zn battery electrolyte creating a metal matrix which aids in nucleation and conductivity. The conductive cuprate ceramics Bi1,7Pb0,3Sr2CuOx (BSCO 2201) and Bi1,7Pb0,3Sr2CaCu2Ox (BSCCO 2212), exhibiting superconductivity at low temperatures (80-100К), also find an application as an additive to the zinc electrode in alkaline Ni-Zn batteries. According to BG Patent Reg. # 111646/2013 this leads to a 30% increase in cycling life. This study is focused on the electrochemical reduction behavior of BSCCO 2201 and BSCCO 2212 conductive ceramics produced by solid state synthesis. It is aimed to elucidate the positive role of these additives on the batteries' functions. Samples of BSCCO were investigated by Cyclic Voltammetry (CV) in a three-electrode cell in a 7M KOH electrolyte at 25oC by using Bio-Logic SP-200 potentiostat/galvanostat. The ceramics were physicochemically characterized before and after galvanostatic reduction using scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDX). Multiple products of partial and complete reduction have been determined: Bi, Cu, Bi2O3, CuO, Ca(OH)2, Sr(OH)2. The CV curves indicate that reduction irreversibly destroys the complex ceramic structure.
Key words: Oxide superconductors, electrochemistry, batteries