Synergistic bulk-interface engineering stabilizes Ni-rich cathode for high-energy lithium-ion batteries

The Ni-rich LiNi 0.9 Co 0.05 Mn 0.05 O 2 cathode materials broaden the development prospects for new energy storage fields with their advantages of low cost and high capacity. Nevertheless, the severe irreversible phase transition and surface corrosion of the material during charge-discharge cycling limits its wide application. To break through this barrier, this work proposes a co-modified synergistic modulation strategy by doping Nb in the bulk phase of the cathode material and depositing Li 3 PO 4 coating layer on the surface. Li 3 PO 4 has good electrochemical stability and can effectively prevent interfacial side reactions, while Nb can inhibit the escape of lattice oxygen and alleviate lattice distortion and stress accumulation. After this internal-external synergistic regulation, the structural stability of the cathode is significantly improved by multiple mechanisms from the bulk to the surface, the electrode polarization is suppressed, and the electrochemical performance and cycle life are further enhanced. Thanks to this synergistic effect, the electrochemical performance of the NCM material is significantly improved, with an initial discharge capacity of 206.5 mAh/g at 0.1C rate, and a capacity retention rate of more than 75 % after 300 cycles at 1C. • Synergistic bulk-interface engineering improves electrochemical performance. • Element doping effectively stabilizes the lattice structure. • Li 3 PO 4 coating inhibits interfacial side reactions. • The Li + diffusion coefficient of the modified sample is significantly improved.