Simultaneous dual modification of Li-rich Mn-based cathode in restraining oxygen release and structure distortion

Abstract

Li-rich Mn-based cathode material (LRM) is one of the most promising cathode materials for achieving high energy density lithium-ion batteries; however, its irreversible anion redox limits its advantages. Herein, these challenges are resolved by introducing a dual modification approach involving Ce, B co-doping and CeO₂ aggregation on Li_1.184Ni_0.136Co_0.136Mn_0.544O₂ (CB-LRM). Density functional theory (DFT) proves that Ce, B co-doping significantly regulates the Mn 3d and O 2p energy bands to improve the stability of lattice oxygen, inhibiting oxygen loss and structural distortion during prolonged cycling. Furthermore, High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) reveals that Ce, B co-doping motivated the transformation from layers to disordered rock salt. Accordingly, the CB-LRM electrode exhibits an impressive cyclability, with 89.6% and 80% capacity retention after 200 cycles at 1C and 3C, respectively, surpassing unmodified LRM (57.3% and 56.8%). This work proposes a novel approach to designing long-life, high-energy-density layered oxide cathodes for lithium-ion batteries.