Four‐In‐One Strategy to Boost the Performance of Na_x[Ni,Mn]O₂

Abstract High‐performance layered oxide cathode materials are vital to the industrialization of Na‐ion batteries (NIBs) due to their high theoretical capacity and facile production. These materials, however, suffer from complicated phase transitions and poor capacity retention cycling. The modifying impacts of classic strategies, such as doping and coating, are generally restricted. Herein, a rational four‐in‐one strategy to boost the overall performance of Na_x[Ni,Mn]O₂ materials by innovative composition design and elegant synthesis management is provided. After modification, the half‐cell capacity retention rate increases from 45% to 77% after 250 cycles at 1 C rate. The capacity of the full cells is maintained at 83% after 300 cycles at 0.5 C rate. This four‐in‐one strategy, which encompasses optimization of the energy band structure, ion diffusion, crystal structure, and particle morphology, sheds new insight into the overall optimization of cathode materials for NIBs.