Oxygen Vacancy Engineering in Titanium Dioxide for Sodium Storage.

Titanium dioxide (TiO2 ) is a promising anode material for sodium-ion batteries (SIBs) due to its low cost, natural abundance, nontoxicity, and excellent electrochemical stability. Oxygen vacancies, the most common point defects in TiO2 , can dramatically influence the physical and chemical properties of TiO2 , including band structure, crystal structure and adsorption properties. Recent studies have demonstrated that oxygen-deficient TiO2 can significantly enhance sodium storage performance. Considering the importance of oxygen vacancies in modifying the properties of TiO2 , the structural properties, common synthesis strategies, characterization techniques, as well as the contribution of oxygen-deficient TiO2 on initial Coulombic efficiency, cyclic stability, rate performance for sodium storage are comprehensively described in this review. Finally, some perspectives on the challenge and future opportunities for the development of oxygen-deficient TiO2 are proposed.