Chemical-Mechanical Effects in Ni-Rich Cathode Materials
Shouyi Yin, Hongyi Chen, Jun Chen, Abouzar Massoudi, Wentao Deng, Xu Gao, Shu Zhang, Ying Wang, Tsung‐Wu Lin, Craig E. Banks, Shi‐Zhang Qiao, Guoqiang Zou, Hongshuai Hou, Xiaobo Ji
Abstract
The implementation of Ni-rich cathodes with high energy density has been critically restrained by stress corrosion. Herein, crack-free LiNbO3-coated LiNi0.88Co0.10Mn0.02O2, as theoretically predicted, demonstrates highly reversible lithiation/delithiation. Mechanically, the phase transition (H1 → H2 → H3) is significantly alleviated by the excogitation of the interfacial force invoked by the LiNbO3 coating layer, as verified by X-ray absorption spectroscopy and extended X-ray absorption near-edge structure spectroscopy. Meanwhile, the stabilities of the crystal structure are remarkably strengthened by the strong Nb–O bond activated by Nb5+ doping that is confirmed by Rietveld refinement of X-ray diffraction and differential capacitance curves. Chemically, the interface shielding effect is conducive to protecting the electrode against electrolyte corrosion along with subsequent transition-metal dissolution, ultimately rendering a faster/highly convertible lithium-ion diffusion. Greatly, the excellent electrochemical properties (74% capacity retention after 300 cycles at 2 C within 2.5–4.3 V) and structural stability (the morphology remains intact after 500 cycles at 5 C within 2.5–4.3 V) are successfully achieved. Given this, this elaborate work might inaugurate a potential avenue for rationally tuning the structure/interface evolution toward Ni-rich materials.