Li-rich Mn-based layered oxides are attractive high-energy cathode materials but suffer from rapid capacity fade and voltage decay due to irreversible lattice oxygen redox. To mitigate this issue, we have developed a cationic/anionic dual-doping strategy involving the coincorporation of Ti4+ and F– ions with the aim of improving the reversibility of lattice oxygen redox reactions in these materials. The Ti/F comodified Li-rich Mn-based layered oxide demonstrates markedly improved cycling stability and rate capability. F and Ti codoping acts complementarily, with F optimizing the local electronic structure to enhance lattice flexibility and Ti strengthening the oxygen framework via robust bonding, significantly improving the reversibility of oxygen redox. Consequently, the Ti/F comodified cathode maintains 87.3% of its initial capacity after 200 cycles at a rate of 1 C and delivers outstanding rate capability, sustaining high capacity even at a demanding 5 C rate. Our dual-doping strategy effectively enhances the lattice-oxygen redox reversibility of Li-rich Mn-based cathodes, offering a new pathway toward high-energy-density Li-metal batteries.
Zou et al. (Mon,) studied this question.