Improving the performance of Li-rich Mn-based cathode materials via combined surface modification with glacial acetic acid and Li3PO4

The surface co-treatment with glacial acetic acid and lithium phosphate for Li-rich Mn-based cathode materials are carried out and systematically investigated. The results show that the combined surface treatment method is superior to any single treatment method. The treatment process of glacial acetic acid, a mono-organic weak acid, is mild and convenient and can improve the particle distribution of the material to make it more loosely distributed, and can effectively activate the Li2MnO3 phase without serious ring-breaking to the crystal structure of the material. In addition, the addition of lithium phosphate helps to reduce the side reaction with electrolytes and helps to replenish the loss of lithium ions during charging and discharging, thus increasing the diffusion efficiency and improving the stability of lithium ions. The electrochemical test results show that the first discharge specific capacity and coulomb efficiency of GP-LMR treated with combined glacial acetic acid and lithium phosphate surface at 0.1C current density increases from the original sample of 229.7 mAh·g−1, 69.25% to 289.7 mAg·g−1, 83.53%. In addition, the discharge specific capacities at higher current densities of 0.5C and 2C are 243.6 mAh·g−1 and 189.3 mAh·g−1, respectively.