Dendrite Growth Suppression by Zn2+‐Integrated Nafion Ionomer Membranes: Beyond Porous Separators toward Aqueous Zn/V2O5 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 Zn2+‐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/V2O5 battery. The Zn2+‐ions coordinated with the SO3− moieties in Nafion result in a high transference number of the Zn2+ cation, all the while facilitating a high ionic conductivity. The Zn2+‐integrated Nafion membrane enables the Zn/V2O5 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 V2O5 (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/V2O5 cells comprising conventional porous separators. A Zn2+‐integrated Nafion ionomer membrane is used as the separator to fabricate aqueous Zn/V2O5 batteries with an exceptional performance over conventional porous separator‐based systems. This is expected to be a breakthrough approach toward transferring zinc‐ion battery technology beyond the laboratory scale. The same approach has potential scope to be adopted in other aqueous rechargeable batteries as well.