Structural characteristics of silver-chromate glasses and performance of silver-chromate electrochemical cells

Abstract

Silver-chromate glasses xAgl-yAg₂O-zCrO₃ (x= 64, 67 and 70 mol% and y/z= 1) were prepared by rapid quenching of the melt. The microstructure of the as-quenched samples showed different surface agglomerates which led to non-uniformity in chemical distribution throughout the sample. The presence of potassium, detected by energy dispersive analysis of X-rays EDAX, was due to contamination of potassium nitrate produced during the preparation of Agl via the double decomposition of silver nitrate and potassium iodide. The battery fabricated from the glass with 70 mol % Agl contaminated with potassium showed an unstable discharge compared to the battery fabricated from glass with 70 mol % Agl of AR grade. This was attributed not only to the formation of low-conducting silver iodide but also to low-conducting potassium compounds which increased the internal resistance of the battery leading to a quick drop in cell voltage.