Synthesis and electrochemical properties of LiMnPO4-modified Li[Li0.2Mn0.534Co0.133Ni0.133]O2 cathode material for Li-ion batteries

- Crystalline LMP with discontinuous distribution is decorated on the surface of LMCN.
- LMP enhances the structural and cyclic stability of LMP-LMCN.
- Voltage decay is suppressed by the surface modification of LMP.
- An appropriate content of LMP improves the high-rate capacity of LMP-LMCN.

Li-rich layered oxides with high specific capacity are considered as the next generation cathode materials for advanced Li-ion batteries. However, the large initial irreversible capacity loss, inferior cycling stability and fast voltage decay still remain to be overcome before large-scale practical applications. In this work, inspired by LiMnPO4 with superior thermal and chemical stabilities and high redox potential, we design and fabricate a series of LMnPO4-modified Li[Li0.2Mn0.534Co0.133Ni0.133]O2 composites. Among them, Li[Li0.2Mn0.534Co0.133Ni0.133]O2 modified with 5 wt.% LiMnPO4 (LMP5-LMCN) sample presents remarkable electrochemical properties with high initial discharge capacity of 292 mAh g−1 and good capacity retention of 78.65% after 100 cycles at current density of 30 mA g−1. The effects of LiMnPO4 as the surface modification layer on the electrochemical performance of Li[Li0.2Mn0.534Co0.133Ni0.133]O2 are systematically investigated. Our results demonstrate that the appropriate LiMnPO4 surface modification could not only enhance the structural stability, but also greatly suppress the voltage fading, which is beneficial to improve the cycling stability and rate capability of Li-rich layered oxides.