A Layered Lithium-Rich Li(Li0.2Ni0.15Mn0.55Co0.1)O2 Cathode Material: Surface Phase Modification and Enhanced Electrochemical Properties for Lithium-Ion Batteries

Layered lithium-rich oxides are recognized as promising cathode materials for lithium-ion batteries (LIBs), owing to their high-energy density, high voltage, high specific capacity, and low cost. However, it remains a critical challenge to realize the high capacity of layered lithium-rich oxides. Herein, we synthesize the Li-rich Li(Li0.2Ni0.15Mn0.55Co0.1)O-2 cathode material by using the sol-gel method and induced a spinel phase on its surface through carbonization-reduction engineering. The surface-modified sample exhibited both improved capacity and rate capabilities. The initial discharge capacity of the treated sample reached 279.6mAhg(-1) at 0.1C, which was 11% higher when compared to the as-prepared sample (252.6 mAhg(-1)). In addition, a discharge capacity of 239.4 and 235.9mAhg(-1) after 100 cycles at 0.5C and 1C (1C = 250mAhg(-1)) could be still obtained for the modified sample, respectively. The enhanced properties were attributed to the increased ionic conductivity through the formation of 3D diffusion paths and reduced structural transformation, owing to the spinel structure decoration on the surface.