Oxygen vacancy regulated TiNb2O7 compound with enhanced electrochemical performance used as anode material in Li-ion batteries.

TiNb 2 O 7 compound with extra oxygen vacancies is synthesized through unique supercritical fluid process. When fabricated as anode for lithium ion batteries, such TiNb 2 O 7 anode exhibits high initial discharge capacity of 231 mA h g−1 at a current density of 100 mA g−1, and maintains capacity of 169 mA h g−1 even after 250 cycles in the voltage window of 1.0–3.0 V. The excellent electrochemical performance is mainly attributed to the existence of abundant oxygen vacancies in TiNb 2 O 7 compound, which greatly increases the electronic conductivity and lithium ion diffusion coefficient. Furthermore, the contribution of pseudocapacitive effect to the superior electrochemical performance of as-prepared Ti Nb 2 O 7 is investigated systematically. All in all, it demonstrates that the supercritical fluid is a facile and effective media to create oxygen vacancies in TiNb 2 O 7 , and the TiNb 2 O 7 compound with introduced oxygen vacancies would be a promising candidate for anode materials in high-power lithium ion batteries. This work provides a fresh strategy and route to explore novel multicomponent oxide materials with enhanced electrochemical properties for energy storage. [ABSTRACT FROM AUTHOR]