LITHIUM-ION BATTERY WITH PASSIVATION-FREE ELECTRODES

摘要

The Li-ion cell Li_4Ti_5O_(12)//polymer gel electro-lyte//LiMn_2O_4 consists of stable electrodes, which do not depend on the formation and growth of passivating surface layers. Thus excellent charge-discharge balance was maintained over 250 full-depth, high rate test cycles with >99.9% coulombic efficiency. Capacity fade was very low, 0.12% and 0.05% at cycles 100 and 200, respectively. Excellent material utilizations at high rate were achieved with 140 mAh/g Li_4Ti_5O_(12), 100 mAh/g LiMn_2O_4 at the C rate and 92 mAh/g Li_4Ti_5O_(12), 70 mAh/g LiMn_2O_4 at the 7.5 C rate. Pulse discharge sequence at rates up to 16C resulted in even better electrode utilizations. The energy density of the cell, calculated using cell voltage of 2.5V and the cathode and anode capacities observed at the C/10 discharge, is 60 Wh/Kg.