Simultaneous regulation of cations and anions in an electrolyte for high-capacity, high-stability aqueous zinc–vanadium batteries

Safe, inexpensive aqueous zinc-ion batteries (AZIBs) are regarded as promising energy storage devices. However, they still face issues, including dissolution and collapse of the cathode as well as H 2 evolution and the growth of Zn dendrites on the Zn anode. Herein, we simultaneously regulate the cations and anions in the electrolyte for high-capacity, high-stability aqueous zinc–vanadium (Zn–V) batteries based on a bimetallic cation-doped Na 0.33 K 0.1 V 2 O 5 ⋅ n H 2 O cathode. We demonstrate that Na + ​cations suppress cathode dissolution and restrain Zn dendrite growth on the anode via an electrostatic shield effect. We also illustrate that ClO 4 − anions participate in energy storage at the cathode and are reduced to Cl − , generating a protective layer on the Zn anode surface and providing a stable interface to decrease Zn dendrites and H 2 evolution during long-term cycling. When Na + and ClO 4 − are introduced into an aqueous ZnSO 4 electrolyte, a Zn/Zn symmetric cell shows durable and reversible Zn stripping/plating for 1500 ​h at a current density of 1 ​mA ​cm −2 and with an area capacity of 1 mAh cm −2 . Zn/Na 0.33 K 0.1 V 2 O 5 ⋅ n H 2 O full batteries exhibit a high capacity of 600 mAh g −1 at 0.1 ​A ​g −1 and long-term cycling performance for 5000 cycles, with a capacity of 200 mAh g −1 at 20 ​A ​g −1 . • Simultaneously regulating the cation and anion in the electrolyte toward high-performance aqueous zinc-vanadium batteries. • Cation Na + suppresses the dissolution of the cathode and restrains the Zn dendrite on the anode. • Anion ClO 4 − participates in the energy storage at the cathode and is reduced to Cl − forming a protective layer on the anode.