Rechargeable lithium cells with modified vanadium oxide cathodes

Modified vanadium oxide has been prepared by melting V2O5 with additives of 3-3.5% of sodium orthosilicate at 690 degrees C for 3 h followed by fast cooling to an ambient temperature. Charge-discharge characteristics of this oxide were studied as an active cathode material for lithium secondary batteries. The oxide undergoes irreversible transition to become essentially amorphous after first discharge to cut-off voltage of 2 V vs. Li, and then exhibits excellent rechargeability in the 1.5 to 3.9 V potential range. The coin type 2325 size secondary cells have been manufactured and tested with the modified vanadium oxide cathodes and Li-Al alloy anodes. Preliminary shallow cycling modifies the cells' performance and allows to obtain rating capacity 50 mA h in the voltage diapason of 2.0-3.9 V with draining current 0.5 mA. (C) 1999 Elsevier Science S.A. All rights reserved.