Boosting Initial Coulombic Efficiency in Li-Rich Mn-based Cathodes by Tuning Orbital Hybridization

Li-rich manganese-based oxides (LRMO) are promising cathode materials for next-generation lithium-ion batteries due to their high-capacity and low-cost merits. However, the low initial coulombic efficiency (ICE) and irreversible oxygen release of LRMO severely hinder their commercialization processes. Here, we employ glyoxal treatment to modulate the hybridization between transition metal (TM) 3d and oxygen (O) 2p orbitals in LRMO. This approach is found to reduce the Co/Mn t_2g-O 2p hybridization in LRMO while simultaneously activating the Co²⁺/Co³⁺ redox below the Fermi level. Our findings demonstrate that tuning TM 3d-O 2p orbital hybridization can be a viable approach to improve the ICE of LMRO. Specifically, the ICE of LRMO can be elevated from 85.3% to 102.5%, and a high specific capacity of 291.2 mAh g⁻¹ can be achieved at 0.1 C. Moreover, the treated LRMO cathodes exhibit significantly enhanced capacity retention.