Negative Enthalpy Doping Stabilizes P2‐Type Oxides Cathode for High‐Performance Sodium‐Ion Batteries

Abstract P2‐type Na 0.67 Ni 0.33 Mn 0.67 O 2 (NNMO) as cathode material for sodium‐ion batteries (SIBs) largely suffers from continuous accumulation of local stress caused by destructive structural evolution and irreversible oxygen loss upon cycling, leading to rapid capacity degradation. Herein, a strategy of negative enthalpy doping (NED), wherein transition metal (TM) sites are substituted with 0.01 mol each Sn, Sb, Cu, Ti, Mg, and Zn to increase the stability of the TM layers, is proposed. The robust structure of NED‐NNMO significantly suppresses the P2 to O2 phase transition and improves the Na + kinetics upon long‐term cycling. Consequently, the NED‐NNMO exhibits much smoothened voltage platforms and…

• NN
  National Natural Science Foundation of China

  Award: U22A20439
• NS
  Natural Science Foundation of Guangdong Province

  Award: 2024A1515010346