Dynamic Reconstruction of the Surface Lattice to Stabilize Lithium Nickel Oxide Cathodes via Molybdenum Modification
Kuiming Liu, Guoyu Ding, Zhichen Hou, Xinhui Huang, Yiyang Peng, Ruyu Xi, Meng Yao, Yue Li, Meng Yu, Fangyi Cheng
Abstract
Cobalt-free, nickel-rich oxides are promising cathode materials with high energy density but suffer from poor reversibility due to unstable surface and anisotropic phase transitions. We report the performance improvement of LiNiO 2 by Mo doping within the bulk and epitaxial growth of Li 4 MoO 5 on the surface. Mo-modification exerts multiple effects, including construction of a three-dimensional Li + diffusion channel, reduction in surface reaction activity, and alleviation of structural strain, which collectively enhance Coulombic efficiency and stabilize lattice oxygen up to a charging voltage of 4.8 V. The interdiffusion of Li, Ni, and Mo between the surface Li 4 MoO 5 and bulk LiNiO 2 facilitates in situ reconstruction of the surface lattice to form a Mo-rich Li + /Ni 2+ superlattice structure that anchors surface oxygen and promotes liberation of additional Li + from Li 4 MoO 5 for charge compensation. This study reveals the dynamic structural changes of Mo-modified LiNiO 2 and proposes strategies to address lithium-loss and structure-instability issues in cycling nickel-rich cathode materials.