Improving Fast‐Charging Capability of High‐Voltage Spinel LiNi<sub>0.5</sub>Mn<sub>1.5</sub>O<sub>4</sub> Cathode under Long‐Term Cyclability through Co‐Doping Strategy
Xin Gao, Feng Hai, Wenting Chen, Yikun Yi, Jingyu Guo, Weicheng Xue, Wei Tang, Mingtao Li
Abstract
Abstract Co‐free spinel LiNi 0.5 Mn 1.5 O 4 (LNMO) is emerging as a promising contender for designing next generation high‐energy‐density and fast‐charging Li‐ion batteries, due to its high operating voltage and good Li + diffusion rate. However, further improvement of the Li + diffusion ability and simultaneous resolution of Mn dissolution still pose significant challenges for their practical application. To tackle these challenges, a simple co‐doping strategy is proposed. Compared to Pure‐LNMO, the extended lattice in resulting LNMO‐SbF sample provides wider Li + migration channels, ensuring both enhanced Li + transport kinetics, and lower energy barrier. Moreover, Sb creating structural pillar and stronger TM─F bond together provides a stabilized spinel structure, which stems from the suppression of detrimental irreversible phase transformation during cycling related to Mn dissolution. Benefiting from the synergistic effect, the LNMO‐SbF material exhibits a superior reversible capacity (111.4 mAh g −1 at 5C, and 70.2 mAh g −1 after 450 cycles at 10C) and excellent long‐term cycling stability at high current density (69.4% capacity retention at 5C after 1000 cycles). Furthermore, the LNMO‐SbF//graphite full cell delivers an exceptional retention rate of 96.9% after 300 cycles, and provides a high energy density at 3C even with a high loading. This work provides valuable insight into the design of fast‐charging cathode materials for future high energy density lithium‐ion batteries.