Dynamically Responsive and Ionic Conductive Gel Coatings to Realize the Stable Circulation of Zinc Metal Anodes for Zinc-Ion Batteries

Abstract

Dendrite growth, hydrogen evolution, and corrosion reactions of zinc (Zn) metal anodes deteriorate the cyclic performance and hinder the commercial application of high-safety aqueous Zn-ion batteries. Herein, a hydroxyl-rich starch (SS) layer is rationally constructed on Zn anodes (Zn@SS) through a facile coating process to tune the Zn electroplating homogeneity and reduce adverse reactions with the electrolyte. SS layers with strong chelating ability can in situ coordinate with Zn2+ ions within the aqueous electrolyte and form ionic conductive gels, which can decrease the contact area, facilitate ion transportation from the ZnSO4 electrolyte to the metallic Zn anodes, and regulate the plating behavior for Zn2+ ions. Zn@SS symmetrical cells show a prolonged circulation of 3000 h at 2 mA cm–2. Even at a large charge/discharge depth of 5 mAh cm–2, Zn@SS symmetric cells can provide a long lifetime of 1000 h. Zn@SS-V2O5 full cells can operate for 1000 cycles at 1 A g–1. This article offers a novel approach for the surface protection of Zn metal anodes through the construction of dynamic ionic conductive gel layers and widens the applied field of renewable and biodegradable starch-based biomass materials.