Regulating local oxygen covalence and interrupting transition metal migration path by multisite doping to stabilize Li-rich layered cathodes

Lithium-rich manganese-based layered oxides (LLOs) are regarded as a kind of ideal cathode materials of the next-generation lithium-ion batteries owing to their exceptionally high theoretical capacity (>300 mAh g −1 ). Nevertheless, these cathode materials are subject to voltage decay and capacity fading due to the irreversible oxygen release and transition metal (TM) migration. Hence, a multisite doping strategy is proposed to interrupt the migration path of TM ions for LLO cathodes with superior structural stability. Moreover, multisite doping also offers pillar effect, and stabilizes lattice oxygen by the establishment of robust covalent P-O bonds to constrain the removal of electrons from the O 2p band. The P-Mg co-doped sample exhibits enhanced dynamic structural reversibility, lattice oxygen stability, and a significantly augmented resistance to electrolyte corrosion. Consequently, the co-doped sample shows outstanding capacity and voltage stability. Its capacity retention ratio is as large as 92.5 % even after 400 cycles, with a corresponding voltage decay rate of merely 0.688 mV/cycle. Multisite doping strategy presents an innovative approach to mitigating voltage decay and capacity fading of Li-rich Mn-based layered cathodes.