BI4V2O11 AND RELATED-COMPOUNDS AS POSITIVE ELECTRODE MATERIALS FOR LITHIUM RECHARGEABLE BATTERIES

In the search for new intercalation electrode materials, several phase s related to the compound Bi4V2O11 have been tested as positive electr odes in room temperature electrochemical lithium cells. Bi4V2O11, Bi3. 6Pb0.4V2O11-y and Bi4V1.8Cu0.22O11-y are structurally similar compound s differing only from a microstructural point of view. Electrochemical lithium intercalation is not affected by such structural and composit ional differences, since the performance of all these phases is equiva lent. The surprising amount of 8 lithium ions per vanadium atom insert ed 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 t his promising value, the irreversibility found after the first dischar ge slightly reduces the possibilities of these materials as positive e lectrodes in room temperature rechargeable lithium batteries. Even so, the energy density is high enough to consider the materials for futur e improvements.