Electrochemical zinc and hydrogen co-intercalation in Li3(V6O16): A high-capacity aqueous zinc-ion battery cathode

Aqueous zinc-ion batteries (AZIBs) are expected to become a promising alternative to lithium-ion batteries (LIBs) for stationary energy storage. The electrodes research of this green system have severe challenges with materials that allow the insertion/extraction of divalent ions. In this work, Li-3(V6O16) was synthesized in one step by molten salt method as a high storage capacity intercalation cathode material for AZIBs. The reversible electrochemical insertion/extraction of Zn2+ and H+ in Li-3(V6O16) materials were reported. A storage capacity of nearly 350 mAh g-1 is achieved at a current density of 0.1 A g(-1), the capacity remains at 189.8 mAh g(-1) after 1000 cycles at a current density of 1 A g(-1), and the coulombic efficiency always remains at 100%. Ex-situ XRD and Ex situ XPS indicate the co-insertion mechanism of Zn2+ and H+. In addition, the layered structure and multiple oxidation states of Li-3(V6O16) are the reasons for the excellent performance. The Li-3(V6O16) material rarely reported provides a new idea for the selection of AZIBs cathode materials, and the molten salt method also makes the development of this pollution-free and safe battery technology very promising.