Electrostatic interaction strategy stabilizes the crystal structure in ultra-high Ni cathode

Ultra-high Ni layered cathodes LiNi x Mn 1- x O 2 ( x  > 0.9) with high energy density for lithium-ion batteries suffer from severe fatigue failure upon cycling because of the unstable crystal structures at highly delithiated states. Despite efforts to address this issue, enhancing the structural stability by electrostatic interaction between oxygen layers has been overlooked. Herein, we propose an electrostatic interaction strategy via Mn-Mg-Al-Ti medium-entropy doping to improve the fatigue resistance of the crystal structure. As expected, these chosen dopants efficiently impede the distortion, interlacement, and fracture of transition metal slabs in crystal structures by enhancing the electrostatic interaction. Accordingly, the cathode LiNi 0.93 Mn 0.04 Mg 0.01 Al 0.01 Ti 0.01 O 2 delivers superior cycling performance with a capacity retention of 96.1 % at 0.5C after 100 cycles. This work demonstrates the effectiveness of improving the electrochemical performance of ultra-high Ni cathodes by the electrostatic interaction strategy, which is of great significance for their commercial application.