Oxygen-deficient anatase TiO2@C nanospindles with pseudocapacitive contribution for enhancing lithium storage

Abstract

Utilising pseudocapacitive lithium storage is one of the most effective methods to improve the rate performance. In this work, hydrogenated anatase TiO₂ nanospindles with a carbon coating (H-TiO₂@C) are synthesized using a facile hydrothermal process, followed by an annealing treatment of 506 epoxy resin coated TiO₂ nanospindles in a H₂/Ar atmosphere. The hydrogenation process can generate rich oxygen vacancies on the outermost surface of TiO₂ nanospindles. When used as an anode material for LIBs, the H-TiO₂@C electrode exhibits excellent cycling ability and rate performance. It delivers a high reversible capacity of 310 mA h g⁻¹ at 0.1 A g⁻¹ and 126 mA h g⁻¹ at 1 A g⁻¹. The pseudocapacitive contribution is as high as 63.9% as revealed by cyclic voltammetry. Such an excellent electrochemical performance can be ascribed to the synergistic effect of oxygen vacancies and the carbon coating for enhancing the pseudocapacitive effect. This work may provide a new strategy to effectively improve the pseudocapacitive properties of metal oxides.