Dendrite Growth Suppression by Zn 2+ ‐Integrated Nafion Ionomer Membranes: Beyond Porous Separators toward Aqueous Zn/V 2 O 5 Batteries with Extended Cycle Life

The dendritic/irregular growth of zinc deposits in the anode surface is often considered as a major intricacy limiting the lifespan of aqueous zinc‐ion batteries. The effect of separators on the evolution of the surface morphology of the anode/cathode is never thoroughly studied. Herein, for the first time, the efficacy of the Zn 2+ ‐integrated Nafion ionomer membrane is demonstrated as a separator to effectively suppress the growth of irregular zinc deposits in the metallic anode of an aqueous Zn/V 2 O 5 battery. The Zn 2+ ‐ions coordinated with theSO 3 −moieties in Nafion result in a high transference number of the Zn 2+ cation, all the while facilitating a high ionic conductivity. The Zn 2+ ‐integrated Nafion membrane enables the Zn/V 2 O 5 cell to deliver a high specific capacity of 510 mAh g −1 at a current of 0.25 A g −1 , which is close to the theoretical capacity of anhydrous V 2 O 5 (589 mAh g −1 ). Moreover, the same cell exhibits an excellent cycling stability of 88% retention of the initial capacity even after 1800 charge–discharge cycles, superior to that of the Zn/V 2 O 5 cells comprising conventional porous separators.