Suppressed the High-Voltage Phase Transition of P2-Type Oxide Cathode for High-Performance Sodium-Ion Batteries

Sodium-ion batteries (SIBs), using the resourceful Mn-based materials as cathodes, have been considered as promising candidates for large-scale energy-storage applications. However, the representative P2-type Mn-based layered oxide cathode usually suffers from a limited specific capacity and a poor cycle life in Na-ion intercalation and deintercalation processes because of the unavoidable phase transition at a high voltage. Herein, we developed Ru-substituted P2-Na0.6MnO2 as a promising sodium host with a high reversible capacity and cycle life. The multiple characterization investigations reveal that Ru substitution could improve the electronic and ionic conductions and particularly suppress the phase transition of P2–OP4, resulting in the extension of the single-phase reaction region. Ru substitution not only enhances the specific capacity (209.3 mA h g–1) but also improves the rate capability (～100 mA h g–1 at 50 C) and cycling stability. This work may open a new avenue for designing and fabricating SIBs by using Mn-based cathodes with high capacity and stability