Activating the redox reaction of oxygen anions by Li/Ti Co-doped for constructing high-capacity Co/Ni-free P2-type sodium-ion batteries

P2-type cathode materials with good rate performance show significant potential for sodium-ion batteries (SIBs), but their low theoretical capacity limits further development. Here, the Na₀.₇₂Cu₀.₂₁Mn₀.₆₇Li₀.₀₆Ti₀.₀₆O₂ cathode layered material is elaborately designed, and the oxygen redox reaction of the oxygen anions gradually shifts from O²⁻ to O₂⁻ via the synergistic modulation of Li⁺ and Ti⁴⁺, especially at a higher voltage, achieving high-capacity Co/Ni-free SIBs. Notably, the NCMLT electrode delivers a capacity of 127.1 mAh·g⁻¹ after 200 cycles at the 1 C, and attains an outstanding capacity retention of 89.86%. Additionally, the metal oxide cost of the synthesized material is relatively low. Thus, this work provides a new approach to design the cathode for high-performance SIBs and offers a value for further development.