Molybdenum-driven dual redox regulation to improve capacity and stability of manganese-based cation-disordered rock-salt cathodes

Mn-based Li-excess cation-disordered rocksalt (DRX) cathodes have garnered great attention for their flexibility in composition regulation and high capacity stemming from the cooperative involvement of cationic transition metal (TM) and anionic oxygen redox. Whereas, the reported DRXs to date suffer from significant capacity fading with limited cycle lifetime. A comprehensive understanding the local structure evolution in disordered lattice structure and regulating the distinct redox processes is critical to balance the high capacity and cyclability in DRXs. Herein, we incorporate a trace amount of redox-active Mo into bulk phase to regulate transition-metal and oxygen dual redox chemistry. By combining atomic-resolution microscopy and synchrotron X-ray techniques, we reveal that Mo dopants function as an electronic and structural regulator, which not only contributes to the charge compensation to cationic and anionic redox process, but also stabilizes lattice oxygen with improved local structural adaptability. The optimized Mo-doped DRX cathode achieves a high initial discharge capacity of 319.9 mAh g −1 at 10 mA g −1 (vs. 241.8 mAh g −1 for the pristine electrode), and maintains 119.4 mAh g −1 after 60 cycles. This work provides a new strategy to stabilize dual redox processes via trace redox-active doping, facilitating the development of high-performance oxygen-redox DRX cathodes.