A preliminary evaluation of an all-solid-state, polymer electrolytebased, rechargeable lithium battery technology has been undertaken, in terms of its performance under pulsed-discharge conditions. Studies have concentrated on the lithium/poly(ethylene oxide)-lithium perchlorate/ V,O,, system, operating at 120 "C for pulse lengths of 10 ms to 20 s.
For pulses in excess of one second duration, high initial currents, equivalent to an approximate 40C discharge rate, have been observed [e.g. 1.5 A from a 40 mA h cell]. High peak currents can be sustained for tens of pulses of a few seconds duration and high cumulative cathode utilisations obtained. Good cell to cell reproducibility is found and the capability to pulse-charge cells has also been demonstrated.
For pulses of 10 ms duration, the cells exhibit a rapid response and recovery, together with a high current capability, long pulse life and reasonable cathode utilisation. Nine thousand pulses of greater than 1 A [average 1.3 A] were obtained from a 110 mA h cell, with a cumulative cathode utilisation of 25%.
A PE0i2LiC104 electrolyte composition is found to be optimum for operation at 120 "C, in terms of both the type and the proportion of lithium salt used. The use of a novel electrolyte has also allowed the preliminary demonstration of high-rate performance at room temperature.