Mechanically Interlocked Core-Shell Architecture for Stable Nickel-Rich Cathodes

Nickel-rich layered cathodes such as LiNi_0.8Co_0.1Mn_0.1O₂ (NCM) are attractive for next-generation lithium-ion batteries but suffer from rapid capacity decay caused by interfacial side reactions and mechanically induced microcracking. Here we report a bulk-surface synergistic modification strategy that constructs a mechanically anchored interface via Nb⁵⁺ embedding and an external NiNb₂O₆ (NNO) coating. Nb incorporation induces local lattice distortion at the near-surface region, creating an anchoring zone that stabilizes the coating against delamination and expands interlayer spacing to accelerate Li⁺ transport. Simultaneously, the coated NNO layer on NCM effectively suppresses electrolyte penetration and HF-induced corrosion, thereby reducing byproduct formation and transition-metal-ion dissolution during cycling. As a result, the Nb-NCM@NNO cathode delivers a rate capability of 177.76 mAh g^-1 at 5.0 C and achieves a capacity retention of ∼88.24% after 200 cycles. This work establishes an effective interfacial anchoring route for enhancing the durability of Ni-rich layered cathodes.