Advanced lithium batteries for implantable medical devices: mechanistic study of SVO cathode synthesis

Silver vanadium oxide (SVO, Ag 2V 4O 11) was synthesized in solid-state reactions from silver carbonate and silver metal powder starting materials with vanadium oxide (V 2O 5) as the vanadium source. These powders were prepared as primary cathode materials for lithium batteries. Thermal analyses of stoichiometric mixtures of V 2O 5 and silver sources were used to elucidate the mechanism of Ag 2V 4O 11 formation. V 2O 5 reacts with Ag 2CO 3 in a two step decomposition/combination (DC) reaction. Weight gain measured by TGA during the reaction of Ag(0)+V 2O 5 in O 2 indicated the formation of Ag 2V 4O 11. XRD analysis of the synthesis products of the Ag(0)+V 2O 5 reaction indicated the formation of AgV 2O 5 under inert atmosphere and Ag 2V 4O 11 under oxidizing (air or O 2) conditions. The surface area and morphology of the materials were strongly influenced by the synthesis method, linked to the parameters of time, temperature, and reaction atmosphere. The electrochemical performance of the SVO cathode material also depended on the synthesis method, where SVO prepared from the DC reaction mechanism yielded improved long-term performance.