Highly stable aqueous rechargeable Zn-ion battery: The synergistic effect between NaV6O15 and V2O5 in skin-core heterostructured nanowires cathode

Abstract

Abstract The aqueous rechargeable Zn-ion batteries based on the safe, low cost and environmental benignity aqueous electrolytes are one of the most compelling candidates for large scale energy storage applications. However, pursuing suitable insertion materials may be a great challenge due to the strong electrostatic interaction between Zn2+ and cathode materials. Hence, a novel NaV6O15/V2O5 skin-core heterostructure nanowire is reported via a one-step hydrothermal method and subsequent calcination for high-stable aqueous Zn-ion batteries (ZIBs). The NaV6O15/V2O5 cathode delivers high specific capacity of 390 mAh/g at 0.3 A/g and outstanding cycling stability of 267 mAh/g at 5 A/g with high capacity retention over 92.3% after 3000 cycles. The superior electrochemical performances are attributed to the synergistic effect of skin-core heterostructured NaV6O15/V2O5, in which the sheath of NaV6O15 possesses high stability and conductivity, and the V2O5 endows high specific capacity. Besides, the heterojunction structure not only accelerates intercalation kinetics of Zn2+ transport but also further consolidates the stability of the layers of V2O5 during the cyclic process. This work provides a new perspective in developing feasible insertion materials for rechargeable aqueous ZIBs.