Selecting indium-containing systems as solid electrolytes

Abstract

Quasi-binary salt systems InCl3-MeCl2, where Me2+ stands for Mg2+, Cd2+, Zn2+, Sn2+, Co2+, or Mn2+, in the region of solid solutions on the basis of InCl3 are considered. A comparative characteristic of some transport properties of these systems is given and optimum compositions for all systems under consideration are determined. The conduction mechanism that presumably takes place in systems InCl3-MgCl2 and InCl3-CdCl2 is confirmed by data that are obtained with the aid of the Tubandt method. In order to raise the reversibility with respect to the indium ion, also considered is the In2S3-InCl3 system, in which the basis compound is In2S3. Methods of electroconduction and XRD are used to establish the existence of a region of limited solid solutions on the basis of indium sulfide. The current efficiency in a system with solid electrolyte In2S3-InCl3 is determined (CE > 50%) and the dependence of the current efficiency on the electrolysis regime is considered. Thermodynamic investigation of some indium-containing compounds and the doping with indium are conducted with use made of indium-containing solid electrolytes of optimum compositions. Data concerning the magnitude of the alteration occurring in the Gibbs energy during the formation of indium-containing semiconducting compounds, which are close to reference data, are obtained.