Nanofluid Electrolyte with Fumed Al2O3 Additive Strengthening Zincophilic and Stable Surface of Zinc Anode toward Flexible Zinc–Nickel Batteries

Abstract Flexible zinc–nickel batteries (FZNBs) have been considered as a promising power supply for wearable electronics due to the intrinsic safety, high operating voltage and superior rate performance. However, the serious self‐corrosion of zinc and the redistribution of dissolved [Zn(OH) 4 ] 2− on the electrode surface limit the electrochemical performance of FZNBs. Herein, the nanofluid electrolyte with fumed Al 2 O 3 additive is introduced into FZNBs and a protective layer is formed due to the adsorption of Al 2 O 3 on the electrodeposited zinc anode. The protective layer strengthens the zincophilicity of the anode and homogenizes the deposition of [Zn(OH) 4 ] 2− , avoiding the dendrite formation and the shape change of electrode. Meanwhile, by suppressing the [Zn(OH) 4 ] 2− diffusion from the anode surface to the bulk electrolyte, the interface stabilization is effectively promoted, thereby improving zinc utilization rate and inhibiting the corrosion. Hence, the FZNBs assembled with Al 2 O 3 ‐nanofluid electrolyte and electrodeposited zinc anode demonstrates superior energy density of 210 Wh L −1 with a stable cycling of 575 h. Furthermore, FZNBs modified with Al 2 O 3 ‐nanofluid electrolyte have a promising future in the field of wearable and portable electronics.