Insights to Oxygen Vacancy Engineering of TiO2 Anode for Sodium‐Ion Batteries

Rational construction of oxygen vacancies in electrode materials can effectively enhance the comprehensive sodium storage performance of the material. However, how to precisely control and regulate the oxygen vacancies concentration remains to be investigated, and the impact on electrochemical performance is still unclear. Herein, TiO2 nanoparticles with tunable oxygen vacancies concentrations are used as research models, which were fabricated through a simple and effective plasma method. The experimental results reveal that a moderate concentration of oxygen vacancies can significantly improve the electrochemical kinetics and charge conductivity of the TiO2 electrodes. In addition, oxygen vacancies promote the release of fluorine from the fluoroethylene carbonate (FEC) in the electrolyte, inducing a NaF‐rich solid electrolyte interphase, thus ensuring interfacial stability and inhibiting excessive electrolyte decomposition. Consequently, the well‐designed anode exhibits outstanding rate capability (147 mAh g‐1 at 5 A g1) and extremely stable cycling performance (nearly 100%, 3000 cycles). This work provides a feasible method for realizing defect concentration modulation in energy storage materials and offers new insights into interfacial chemistry for improving battery performance.