Regulating zinc deposition behaviors by using a functional PANI modification layer on a separator for high performance aqueous zinc-ion batteries

Abstract

Aqueous zinc-ion batteries (AZIBs) are promising energy storage devices due to their high safety, abundant zinc reserves, high theoretical capacity and low redox potential. Glass fiber (GF) has been widely used as a separator in AZIBs; however, the strong affinity to zinc ions of GF easily induces the growth of zinc dendrites towards the separator and results in a short circuit of the battery. Herein, we propose a new strategy for regulating zinc deposition behaviors by in situ polyaniline (PANI) modification on a commercial GF separator (GF/PANI). The theoretical and experimental results indicate that a PANI modification layer weakens zincophilicity force, homogenizes the surface electric field distribution and induces uniform plating/stripping of zinc ions, and thus, the reversibility of the zinc anode is significantly improved. Typically, a Zn‖Zn symmetric battery with a GF/PANI-600 separator can sustain a longer cycle up to 3000 h at 1.0 mA cm⁻² with 1.0 mA h cm⁻², far exceeding than that with a GF separator (70 h). Additionally, a Zn‖MnO₂ full battery with a GF/PANI-600 separator also delivers a higher capacity retention rate of 89.5% after 300 cycles at 0.5 A g⁻¹ (50.7% that of the Zn|GF|MnO₂ battery). This work provides a new insight into the design of durable AZIBs from the viewpoint of the modification of the separator.