Stabilizing the bulk phase and interface of layered oxide cathode through Li&B double doping

Layered oxide cathodes have attracted widespread attention due to their high-voltage and high discharge capacity. Nevertheless, the irreversible redox reactions of layered oxide cathode and decomposition of electrolyte at high-voltage greatly reduce the reversibility of the batteries. Herein, we employ a double-doping (Li&B) strategy to enhance the electrochemistry performance of the layered NaNi 0.3 Fe 0.3 Mn 0.4 O 2 (NNFM) cathode at high voltage. It proved that the dissolution of the transition metal can be restricted by double doping, and the irreversible phase transition is mitigated even at high voltage. As a result, battery with the double-doping cathode exhibits excellent electrochemistry performance, which achieves a capacity of 175 mAh g −1 at 0.2C, maintaining a capacity retention of approximately 87.3% over 100 cycles at 1C, and demonstrates exceptional rate performance. This work presents a novel insight into the doping technique for the high-performance cathode materials and offers a general method for the high energy Na-ion batteries.