Electrochemical study of the thermodynamic properties of matildite (Β-AgBiS₂) in different temperature and compositional ranges

Thermodynamic properties of matildite (Β-AgBiS₂) in equilibriumwith sulfur and bismuth have been studied by anEMF method, using the fast Ag⁺ ion-conducting solid electrolytes gI and RbAg ₄I₅. The ternary phases were synthesized from the pure binary compounds. Properties of the electrolytes used have been reviewed, and their usage as pure conductors ofAg⁺ ions in the temperature ranges of the electrochemical cells employed was well defined. The EMF measurements were carried out using the solid-state electrochemical cells Pt(-)|Ag|RbAg ₄I₅Β-AgBiS₂+AgBi₃S ₅+S|Pt(+) and Pt(-)|Ag|AgI|Β-AgBiS₂+AgBi ₃S₅+Bi|C|Pt(+), in the temperature range 325-464 K. Based on the obtained results, thermodynamic functions for the formation ofmatildite (Β-AgBiS₂) at sulfur and bismuth saturation have been determined. The obtained experimental values have been compared with the available literature values. New experimentally determined thermodynamic properties of the bismuth-saturated matildite (Β- AgBi₁+xS ₂) and sulfur-saturated matildite (Β-AgBiS₂+ _y) were generated and analyzed in detail.