Lithium intercalation in the divalent metal vanadates MeV2O6 (Me=Cu, Co, Ni, Mn or Zn)

Divalent metal vanadates, MexV2O6, where Me=Cu, Co, Zn, Mn or Ni, were found to reversibly intercalate lithium. These transition metal vanadates were made by a precipitation method which formed a hydrated divalent metal vanadate (MexV2O6·2H2O). The hydrated water was removed by heating the vanadate above 300 °C and composite electrodes were prepared with carbon and polytetrafluoroethylene. The cell voltage and energy density were dependent on both the divalent metal present and the temperature to which the vanadate was annealed. The Zn, Mn, Co and Ni vanadates were reversible to lithium intercalation at average voltages from 1.3 to 1.9 V (versus Li) and their specific capacities were dependent on the annealing temperature. The copper vanadate yielded the best cell voltage and energy density.