Surface coating with Li3BO3 protection layer to enhance the electrochemical performance and safety properties of Ni-rich LiNi0.85Co0.05Mn0.10O2 cathode material

Abstract To enhance the electrochemical properties and safety performance of Ni-rich cathode materials for Lithium-ion batteries, a typical wet chemical method followed by high temperature sintering was applied to make the Li+ conductive Li3BO3 with different mass fractions cover on the surface of Ni-rich LiNi0.85Co0.05Mn0.10O2. And the influence of the coating layer on the phase, crystal structure, particles morphology and electrochemical properties during cycling were systematically studied. The physicochemical characterization results suggested a coating layer with a thickness of 10–15 nm formed by Li3BO3 nanoparticles was equably adhered on the surface of cathode particles, without causing obvious variation of the crystal structure and morphology. The electrochemical measurement indicated the suitable amount of Li3BO3 coating layer could effectively enhance the rate capability, discharge ability at low temperature and cycling performance of LiNi0.85Co0.05Mn0.10O2 due to the increased Li+ diffusion rate and restrained side reaction from electrode with electrolyte. Particularly, the 2 wt% Li3BO3 coated LiNi0.85Co0.05Mn0.10O2 respectively delivered a capacity retention of 91.4% and 90.1% at 25 °C and 45 °C after 300 cycles, and the pristine one merely retained a capacity retention of 83.9% and 80.4% accordingly. Besides, the pouch full batteries with 2 wt% Li3BO3 coated LiNi0.85Co0.05Mn0.10O2 cathode demonstrated the obvious enhancement on the safety properties and storage performance when compared to the pristine one for the pouch batteries