Rechargeable Lithium Batteries Based on the Ternary Chevrel Phase AgMo6 S 8 as the Cathode

Interest in examining the electrochemical insertion of lithium into framework crystal structures has arisen recently because of electrolyte limitations associated with the cointercalation of organic solvents encountered with other low dimensional intercalation materials ( i.e. , compounds built up of layers or chains of atoms) such as the layered transition metal dichalcogenides. Several materials with framework structures have been studied with most of the attention focused on the binary Chevrel phase which was found to reversibly accommodate four lithium atoms per unit formula resulting in a theoretical energy density of 280 Wh/kg. However, difficulties in preparing this phase by conventional means have hindered its synthesis and subsequent use in secondary lithium cells. In this paper we give evidence from electrochemical and in situ x‐ray studies that can be electrochemically converted to plus silver metal and then show that (which can be formed directly from the pure elements) can be substituted for as the cathode material in secondary lithium cells. Cycling data indicates that during such electrochemical conversion the cell capacity is not affected and furthermore these cells have a long cycle life, good discharge rate capability, and no self‐discharge. During this study we also report that can be prepared in a thin film form (as thin as 1 μm). Such ability combined with the above electrochemical properties, make the electrode an excellent candidate for new thin film batteries.