Study on Modified High Voltage (5V) Spinel Lithium Manganate Used for Energy Storage Lithium Titanate Batteries

摘要

Solid electrolyte Li_(1.4)Al_(0.4)Ti_(1.6)(PO_4)_3 was used to coat high voltage (5V) spinel lithium manganate. The modified high voltage spinel lithium manganate was used as positive electrode and the lithium titanate as negative electrode. A type of 10Ah energy storage battery was assembled. Charge-discharge and cycle life tests of these batteries were carried out at different temperatures and rates. The results show that coating high voltage spinel lithium manganate improves the high temperature cycle performance of the lithium titanate batteries. The capacity retention ratio of the lithium titanate batteries with the coated high voltage lithium manganate as cathode material increases from 74.8% to 86.5% at 60°C after 2000 cycles compared to the lithium titanate batteries with the uncoated high voltage lithium manganite as cathode material. However, the cycle performance is not affected at -30°C. The low temperature rate performance of lithium titanate batteries is improved by coating high voltage lithium manganate. When the discharge rate is 20 C at -30°C, 90.6% of the 1 C charge capacity at room temperature of the lithium titanate battery with the coated high voltage lithium manganate as cathode material can be delivered, while the lithium titanate battery with the un-coated high voltage lithium manganate as cathode material can only deliver 80.2% of the 1 C charge capacity at room temperature.