Enhanced cycling stability of single‐crystal LiNi <sub>0.83</sub> Co <sub>0.07</sub> Mn <sub>0.10</sub> O <sub>2</sub> by Li‐reactive coating with H <sub>3</sub> BO <sub>3</sub>
Wenhui Hu, Ya Yin, Ya Sun, Guo-Xue Liu, Shun-Yi Yang, Youyuan Huang, Bo Wang
Abstract
Abstract Ni‐rich cathode materials will be primarily used as next‐generation high‐specific energy cathode materials in lithium‐ion batteries. However, residual Li formation and cracking considerably restrict the wide application of these materials. To address the issues related to cracking, micro‐sized single‐crystal cathode materials without internal grain boundaries are proposed. In this study, we constructed a thin LiBO 2 layer on the single‐crystal LiNi 0.83 Co 0.07 Mn 0.10 O 2 particles by solvent‐free H 3 BO 3 modification. The residual Li on the material surface decreased by 14% through the reaction of LiOH/Li 2 CO 3 and H 3 BO 3 . The coated materials exhibited higher initial Coulombic efficiency (88.44%), higher reversible capacity (213.4 mAh·g −1 at 0.1C), and better cycling performance (91.31% retention over 50 cycles within 3.0–4.3 V at 1.0C) than the unmodified materials. Using the galvanostatic intermittent titration technique, electrochemical impedance spectroscopy (EIS), and inductively coupled plasma‐optical emission spectroscopy (ICP‐OES), we reveal the mechanism by which the electrochemical properties are improved upon H 3 BO 3 modification. The superior electrochemical performances are associated with increased Li + conductivity, lower charge transfer impedance, and suppressed transition metal dissolution. Therefore, this study demonstrates the importance of surface modification in obtaining Ni‐rich single‐crystal materials with enhanced performance.