Designing an asymmetric local hydration environment within gel polymer electrolytes (GPE) between the cathode and anode is a critical strategy for high-performance aqueous zinc-metal batteries (AZMBs). At the anode (Zn metal), water activity must be suppressed to inhibit corrosion, whereas the cathode requires sufficient hydration to enhance specific capacity. However, conventional GPEs possess three-dimensional polymer networks with uniformly distributed water, making it challenging to satisfy the conflicting hydration requirements for both electrodes.
In this study, acrylonitrile (AN), normally insoluble in water, is dissolved in aqueous solution via a salt-induced strategy and simultaneously combined with an asymmetric substrate polymerization to fabricate a Janus GPE through one-pot synthesis. This GPE exhibits gradient pore and hydrophilicity, thereby minimizing parasitic reactions at both electrodes and achieves 94% capacity retention after 100 cycles in a Zn//NVO full cell.