Synergistic structure and oxygen-vacancies engineering of lithium vanadate for kinetically accelerated and pseudocapacitance-dominated lithium storage

The high reversibility, capacity, and safety make lithium vanadate (LVO) an attractive anode to Li-ion batteries, yet they still suffer from the low intrinsic electrical conductivity and ion diffusion rate. Modulating the electronic and crystal structure of materials by vacancies engineering could significantly affect the lithium storage performance. Herein, high concentration of oxygen-vacancies incorporated Li3VO4 nanowires (HLVO) were prepared to make up conductivity and ion diffusion kinetics of LVO as a competitive fast-charging anode. The oxygen-vacancies were derived from the controllable oxidation of local V4+ ions via the thermal treatment, enabling the redistribution of electrons and optimized charge-transport properties of LVO on the basis of the experimental results and theoretical calculations. The reduced reaction energy barriers, enhanced Li-ion diffusion, improved electrical conductivity, and additional active sites induced by oxygen-vacancies drastically accelerate the redox kinetics, enhancing the capacitive behavior. Thus, the HLVO anode delivers superior electrochemical performance with large specific capacities of 553.8 mA h g(-1), exceptional rate capacity of 312.2 mA h g(-1) even at 4.0 A g(-1) and excellent cycling stability. This finding provides the credence to the prospect of vacancy engineering contributing to develop the matter-of-fact transition metal oxides as high-performance anodes for Li-ion batteries.