Solid State Ionics, Vol.123, No.1-4, 139-153, 1999
Synthesis and electrochemical properties of cobalt vanadates vs. lithium
A coprecipitation method has been used to prepare several cobalt-based vanadates. New hydrates such as beta-Co(VO3)(2). 2H(2)O, Co2V2O7. 3.3H(2)O, Co-3(VO4)(2). 12H(2)O and (NH4)(2)Co2V10O28. 16H(2)O have been obtained. During the synthesis, several parameters, namely the pH value, must be finely controlled to prepare pure phases. Thermal treatment of these: hydrated precursors give well-known related anhydrous compounds as well as new ones such as beta-Co(VO3)(2). All these materials were tested for their electrochemical properties vs, lithium. The best results were obtained for the alpha-Co(VO3)(2) phase that can reversibly react with 9.5 lithium ions with only 17% of irreversible capacity leading to a total reversible capacity of 600 mAh/g after the 5th cycle.