A NEW METHOD FOR THE QUANTITATIVE-ANALYSIS OF SILVER-OXIDE CATHODES

A new method based on x-ray diffraction (XRD), thermogravimetry (TG), and gas chromatography (GC), has been developed for the quantitative analysis of silver oxide cathode materials. This method takes into account (i) the existence of Ag4O3, a newly discovered oxygen deficient phase of silver oxide, and (ii) the occurrence of the solid-state reverse disproportionation reaction between AgO and Ag to form Ag2O during the TG procedure. In this analysis procedure we use the general formula, AgO1−δ (δ is the degree of oxygen deficiency in AgO), to represent a mixture of AgO and Ag4O3. The weight fractions of AgO1−δ, Ag2O, and Ag were determined by XRD and that of Ag2CO3 by XRD and/or GC. The degree of oxygen deficiency, δ, was then determined from TG weight loss data. This new comprehensive analysis method is being used to determine compositional changes (aging) in silver oxide cathodes and to relate the changes to battery performance degradation problems. Oxygen deficiency in AgO is a major cause of the high thermal instability seen in many silver oxide cathodes. © 1990, The Electrochemical Society, Inc. All rights reserved.