An all-vanadium aqueous lithium ion battery with high energy density and long lifespan

Abstract Aqueous Li ion batteries offer a safe and low cost alternative to their organic electrolyte counterparts; however, they usually suffer from poor cyclability due to the structural instability of electrode-active materials in the aqueous electrolytes. In the light of excellent electrochemical reversibility of vanadium-based redox couples in redox flow batteries (RFB), we propose an all-vanadium aqueous lithium ion battery (VALB) using a LiVOPO 4 cathode and a VO 2 anode, and a 20 m LiTFSI aqueous solution as electrolyte, respectively. This VALB battery demonstrates excellent electrochemical performances with an average operating voltage of ~1.4 V, an attractive energy density of 305 W h L −1 and 84.0 W h kg −1 based on the total active materials mass, considerably exceeding the energy density of conventional Vanadium flow battery. In addition, this battery also demonstrates an excellent cycling stability with 84% capacity retention over 1000 cycles, possibly serving for energy storage applications.