Hydrogels with amphiphilic chains and targeted adhesion for high-areal-capacity zinc batteries

Abstract

Two impending problems of practical rechargeable aqueous zinc metal batteries (RZMBs) are the underutilization of high-loading materials at the cathode side and zinc dendrite at the anode side. Herein, based on hydrophobic association, we report the amphiphilic hydrogel electrolytes featured by unique hydrophobic association and target permeation properties, which enables full utilization of dense thick cathode materials with loading masses approaching a practical level. Meanwhile, the ion tunnels within the amphiphilic hydrogel electrolytes can regulate Zn²⁺ migration and homogenize interfacial deposition at different current densities, rendering a smooth and compact Zn morphology in a dendrite- and passivation-free manner. Meriting these advantages of the amphiphilic hydrogel electrolytes, the assembled Zn||MnO<inf>2</inf> batteries delivered a high areal capacity of >2.0 mAh cm⁻² for 200 cycles at a large MnO<inf>2</inf> loading mass up to 16.8 mg cm⁻². Further, large-sized (up to 200 cm⁻²) Zn||MnO<inf>2</inf> pouch batteries were demonstrated. This work opens a new avenue toward realizing viable RZMBs with practical large areal capacities and sizes.