Synergistic energy band modulation and interfacial structure engineering for highly-reversible anionic redox in Li-rich Mn-based layered oxides

Anionic redox plays a critical role in contributing to the high specific capacity of Li-rich Mn-based layered oxide (LLO), enabling lithium-ion batteries (LIBs) to reach energy densities up to 500 Wh kg-1 at the cell level. However, the activation of unstable O species at high voltages inevitably leads to structural instability and interfacial degradation, posing significant challenges for practical applications. Herein, we report a rapid low-temperature strategy to engineer a grain-level layer comprising surface LiZr2(PO4)3 (LZP) and an interfacial layered-spinel heterostructure on LLO, improving the reversibility of anionic redox and Li+ diffusion kinetics. The LZP surface layer modulates the antibonding (TM‒O)* (TM represents a blend of 3d transition metals) and O 2p nonbonding bands in LLO, which enhance the reversibility of electron transfer and the stability of O species, thereby suppressing the irreversible structural transformation and parasitic reaction. Furthermore, the interfacial layered-spinel heterostructure forms three-dimensional (3D) Li+ diffusion channels, stabilizing structure and promoting Li+ migration. Consequently, the designed LLO exhibits an impressive discharge capacity of 303.0 mAh g-1 and outstanding cycle life with 81.0 % capacity maintenance over 500 cycles in full cells. The strategy of synergistic energy band modulation and interfacial structure engineering shows great promise in exploring advanced cathode materials for high-energy-density LIBs.