The effect of B 2 O 3 /Li 3 BO 3 coating and B 3+ doping on electrochemical properties in nickel-rich single-crystal LiNi 0.7 Co 0.2 Mn 0.1 O 2 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 LiNi 0.7 Co 0.2 Mn 0.1 O 2 (NCM) cathode is treated with H 3 BO 3 through a simple wet chemical process. Surprisingly, H 3 BO 3 shows multifunctional effect on the electrochemical performance of NCM, both through a generation of B 2 O 3 /Li 3 BO 3 coating layers and B 3+ incorporation into the bulk phase, and the fundamental understanding of multifunctional effect are investigated through crystal structure and chemical states. The B 2 O 3 /Li 3 BO 3 coating layers act as artificial barriers and Li + -conductor on the surface, which inhibit Ni dissolution and accelerate lithium ions migration. Additionally, B 3+ 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 H 3 BO 3 modification. The multifunctional effect of H 3 BO 3 provides a reference for the development and modification of lithium ions cathode materials in the future.