Inhibiting lattice strain for highly stable and long‐life Li‐rich Mn‐based layered cathodes

Abstract The utilization of Li‐rich layered oxides (LLOs) as cathodes in high‐energy Li‐ion batteries is significantly hindered by serious voltage decay and capacity fading due to irreversible oxygen release and transition metal (TM) migration triggered by the lattice strain. Herein, B ions are effectively incorporated into the tetrahedral vacancies situated between TM slab and Li layer of LLOs. The robust B‐O bond, along with the low Bader charge of oxygen within BO 4 tetrahedra, alleviates excessive oxidation of O anions while substantially reinforcing the oxygen framework. Consequently, the B‐doped LLO sample exhibits only slight variation in lattice parameters, especially the c ‐axis, which can be characterized as exhibiting “zero‐strain” as supported by in situ XRD data. As a result, the discharge capacity of the B‐LLO sample maintains 210.66 mAh·g −1 after 300 cycles, with a retention ratio of 90.7%.