Effect of surface alkalinity reduction on cycling and rate performance of LiNi0.8Co0.15Al0.05O2 cathode materials for lithium-ion batteries

Abstract The LiNi0.8Co0.15Al0.05O2 cathode material was synthesized by solvothermal method using ethanol as solvent. And Al2O3 and H3BO3 were coated on the surface of the material by a wet method to reduce the surface alkalinity. The modified material exhibited a capacity retention of 89.2% after 1C, 100 cycles and showed significantly enhanced rate performance with a capacity of 160.9 mAh g-1 at 5 C. The excellent electrochemical performance can be attributed to that the composite coating of Al2O3 and H3BO3 prevented contact between the electrolyte and the active material, stabilized the material structure and inhibited the dissolution of transition metals during repeated charge-discharge cycles.