Improved Rate Capability in a High-Capacity Layered Cathode Material via Thermal Reduction

Thermal treatment of the high-capacity integrated-structure cathode material Li 2 MnO 3 -LiMO 2 (M = Mn, Ni, and Co) under a reductive H 2 atmosphere was investigated as a means to improve its rate capability when incorporated into a Lithium-ion battery (LIB). The heat-treated electrode, with a composition of Li 1.12 Mn 0.55 Ni 0.145 Co 0.1 O 2 , shows a better coulombic charge-discharge efficiency and a good cycleability than the pristine material. This improvement can be attributed to a reduction in the valence of some Mn ions from 4 + to 3 + , as monitored by X-ray photoelectron spectroscopy.