Synergistic regulation of kinetic reaction pathway and surface structure degradation in single-crystal high-nickel cathodes.

ABSTRACT

As a promising high energy density cathode, single-crystal Ni-rich cathode face poor diffusion dynamics, which leads to poor structural evolution, poor cyclic stability and unfavorable rate performance, thus impeding its wider application. Herein, the strategy of synergistic surface modification by ionic conductor coating and trace element doping is delicately designed. The surface protective Li3BO3 layer is wrapped on the single-crystal LiNi0.83Co0.11Mn0.06O2 (NCM83), which can improve the compatibility of cathode/electrolyte with reduced interface resistance. While Zr is incorporated into bulk to stabilize the crystal structure and migration channel. This synergistic strategy achieves the improvement of ionic transport and structural stability of single-crystal NCM83 (Zr-NCM83@B) from the outer surface to the inner body. As expected, the modified cathode Zr-NCM83@B demonstrates a satisfying electrochemical performance. It delivers a high reversible capacity of 169 mAh g-1 in coin-type half-cell at 4C within 3.0-4.3 V. Remarkably, it displays excellent capacity retention of 83.5 % in Zr-NCM83@B || graphite pouch-type full-cell over 1400 cycles at 1C with high voltage range of 2.8-4.4 V. This synergistic surface modification provides a reference for commercial development of advanced single-crystal Ni-rich cathode under harsh testing conditions.