Layered over-lithiated oxide coating for reviving spent LiCoO2 cathode for stable high-voltage lithium-ion battery

Abstract

Layered lithium-rich manganese-based materials with high voltage stability and high energy density are used to modify the surface of spent LiCoO2 materials (LCO) for designing high-performance Li+-storage structures with high specific capacity and high voltage cycling stability. In this typical regeneration process, Mn2+, Co2+, Ni2+, and Li+ acetates were introduced as raw materials for coating Li1.20Mn0.54Co0.13Ni0.13O2 (LLO) on the surface of spent LCO particles uniformly via a sol-gel method. The structural, morphological, and elemental-chemical-state characterisation results indicate that the recycled [email protected] materials exhibit a typical core-shell structure, with a layer-structured-Li1.20Mn0.54Co0.13Ni0.13O2 layer ~ 10 nm thick as the high-voltage-stable-shell and a well-ordered layer-LiCoO2 as the high-capacity-core. As expected, the regenerated [email protected] composites show an upgraded Li+-storage performance compared to bare LCO. The optimised [email protected] materials show an initial capacity of 197.1 mAh g−1 at 0.1 C, and ~ 95.8% retention after 100 cycles under 3.0–4.5 V at a rate of 1 C. All results indicate that this highly efficient, LLO assisted modification regenerate strategy can be easily extended to regenerate other spent cathodes to synthesise advanced energy storage materials with high voltage cycle stability and high specific capacity.