Multi‐Level Engineering from Surface to Bulk Enabling Highly Stable Ni‐Rich O3‐Type Cathode toward Temperature‐Tolerant Quasi‐Solid‐State Na‐Ion Batteries

Abstract The pursuit of high‐capacity Na‐ion batteries (NIBs) has propelled great forward the O3‐type Ni‐rich NaNi_0.5Co_0.2Mn_0.3O₂ (NCM) cathodes. However, the inborn chemo‐mechanical instabilities caused by complex phase transitions and anisotropic lattice stress have severely delayed its widespread application. In the contribution, a cooperative surface‐to‐bulk modification strategy, i.e., in situ surface NaTi₂(PO₄)₃ (NTP) coating and bulk Ti/F co‐doping, is first proposed to engineer an advanced NCM cathode (denoted as TF‐NCM@NTP). The NTP protective layer with high thermodynamic stability and ionic conductivity endows TF‐NCM@NTP with a highly stable interface and expedited de‐/sodiated kinetics. The robust Ni/Co/Mn─F bond and concurrent Ti─O bond greatly strengthen the bulk lattice oxygen and mitigate the internal strain self‐reproduction. Benefiting from these synergistic merits, the designed TF‐NCM@NTP cathode demonstrates exceptional sodium‐storage performance in terms of high‐rate capacities and long‐duration cycle life in both half and full cells. Particularly, the TF‐NCM@NTP‐based quasi‐solid‐state NIBs deliver an applicable material‐level energy density of 285 Wh kg⁻¹ at 25 °C, and exhibit wide‐temperature‐tolerant Na‐storage behaviors ranging from −20 to 50 °C. More essentially, the multi‐level engineering strategy from surface to bulk developed here definitely makes enormous progress for rationally designing advanced cathode materials toward multi‐scenario applicable NIBs.