The effect of B2O3/Li3BO3 coating and B3+ doping on electrochemical properties in nickel-rich single-crystal LiNi0.7Co0.2Mn0.1O2 cathodes

The sluggish ionic transport and interface stability for single-crystal nickel-rich materials are the main challenge hindering its large-scale applications. Herein, the single-crystal LiNi0.7Co0.2Mn0.1O2 (NCM) cathode is treated with H3BO3 through a simple wet chemical process. Surprisingly, H3BO3 shows multifunctional effect on the electrochemical performance of NCM, both through a generation of B2O3/Li3BO3 coating layers and B3+ incorporation into the bulk phase, and the fundamental understanding of multifunctional effect are investigated through crystal structure and chemical states. The B2O3/Li3BO3 coating layers act as artificial barriers and Li+-conductor on the surface, which inhibit Ni dissolution and accelerate lithium ions migration. Additionally, B3+ doping can strengthen Li+ diffusion rate in the layered structure. As a result, the electrochemical performance of the modified NCM material is enhanced. The 87.4% capacity retention of the initial capacity after 150 cycles at 1 C with a high work voltage of 4.5 V and high reversible capacity of 162.7 mAh g−1 at 10 C rate can be obtained through H3BO3 modification. The multifunctional effect of H3BO3 provides a reference for the development and modification of lithium ions cathode materials in the future.