Bi4V2O11 and related compounds as positive electrode materials for lithium rechargeable batteries

In the search for new intercalation electrode materials, several phases related to the compound Bi4V2O11 have been tested as positive electrodes in room temperature electrochemical lithium cells. Bi4V2O11, Bi3.6Pb0.4V2O11-y and Bi4V1.8Cu0.22O11-y are structurally similar compounds differing only from a microstructural point of view. Electrochemical lithium intercalation is not affected by such structural and compositional differences, since the performance of all these phases is equivalent. The surprising amount of 8 lithium ions per vanadium atom inserted in Bi4V2O11 during the first discharge at an average potential of 1.7 V implies a theoretical specific energy of 655 Wh/Kg. In spite of this promising value, the irreversibility found after the first discharge slightly reduces the possibilities of these materials as positive electrodes in room temperature rechargeable lithium batteries. Even so, the energy density is high enough to consider the materials for future improvements.