Strain engineering of particles and interfaces for long-life stable LiNi_0.8Co_0.1Mn_0.1O₂ cathodes

High-nickel layered cathode materials undergo structural degradation caused by enlarged internal stress arising from Li⁺/Ni²⁺ cation mixing and lattice oxygen release, which accelerates capacity decay and raises safety concerns. To mitigate this stress, a rational design of LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) was developed through precise strain engineering by Mo⁶⁺ and Sb³⁺ co-doping. Compared with pristine NCM811, the incorporation of Sb³⁺ significantly reduced the lattice distortion, thereby enabling stable and reversible Li⁺ de/intercalation and suppressing the migration from Ni²⁺ to Li⁺ sites. Meanwhile, Mo⁶⁺ doping established stronger Mo–O coordination in the bulk and formed electrochemically stable Li₂MoO₄ at the interfaces, which decreased the bulk stress by reducing oxygen release and simultaneously enhanced resistance to electrolyte corrosion. Thus, this strain-engineering strategy produced robust NCM811 lattice and interface structures, favorable for the construction of stable particles and thinner, more homogeneous cathode-electrolyte interfaces. The assembled pouch full cell (∼0.8 Ah) achieved a markedly improved capacity retention ∼93 % after 1000 cycles at 1 C (capacity retention ∼69 % after 500 cycles in the pouch cell assembled with pristine NCM811), compared with the state-of-the-art values typically below 85 %. This strategy provides an effective route for developing stable Ni-rich cathodes for long-term lithium-ion batteries.