Dynamic Reconstruction of the Surface Lattice to Stabilize Lithium Nickel Oxide Cathodes via Molybdenum Modification

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 LiNiO2 by Mo doping within the bulk and epitaxial growth of Li4MoO5 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 Li4MoO5 and bulk LiNiO2 facilitates in situ reconstruction of the surface lattice to form a Mo-rich Li+/Ni2+ superlattice structure that anchors surface oxygen and promotes liberation of additional Li+ from Li4MoO5 for charge compensation. This study reveals the dynamic structural changes of Mo-modified LiNiO2 and proposes strategies to address lithium-loss and structure-instability issues in cycling nickel-rich cathode materials.