An overview of the modification strategies for P2-Na2/3Ni1/3Mn2/3O2 cathode for sodium ion batteries

P2-type Na 2/3 Ni 1/3 Mn 2/3 O 2 (NNM), a promising candidate cathode material for advanced sodium ion batteries, has been extensively investigated in terms of its excellent electrochemical performance, straightforward preparation process, cost-effectiveness, and similarities to well-established Li-ion counterparts. However, the specific capacity, rate capability and cycling stability are severely dragged down by irreversible phase transitions, Na+/vacancy + /vacancy ordering, and interface deterioration. Research progress related to modification strategies for boosting the performance of P2-NNM cathodes in SIBs is provided. The perspectives and development directions for the optimization strategies for NNM cathodes are also presented. This review systematically and comprehensively elaborates the modification strategies for NNM cathodes, furnishing a positive guideline for designing and optimizing P2-NNM cathodes for the burgeoning commercial SIBs market.