A Robust Gel Polymer Electrode with Controlled-Release Polymerization towards Practical Lithium-Sulfur Batteries

While rational electrode engineering has promoted the kinetics of lithium-sulfur batteries, persistent lithium polysulfide diffusion continues to undermine the cyclability of conventional liquid electrolyte systems. We propose a quasi-solid gel electrode design that integrates the sulfur species-blocking attributes of a solid-state system within a liquid electrolyte framework. This is achieved through a well-designed free radical-controlled-release polymerization strategy, which precisely governs the formation of a processable poly(ethyl cyanoacrylate) network. This approach enables secondary in situ gelation triggered by electrolyte infiltration, forming gel-phase electrode architectures. Mechanistically, the resulting gel-based electrode provides dynamically adaptive stress dissipation to accommodate volume variations, establishes continuous ion-permeable pathways for deeper positive electrode discharge, and acts as a synergistic physico-chemical barrier for sulfur species confinement. As a result, the positive electrode delivers a high initial capacity of 812.8 mA h g–1 at 2 C and sustains stable cycling operation over 1000 cycles. A 1.7 Ah-level pouch cell demonstrates potential for a sustained power supply for an unmanned aerial vehicle. A free radical-controlled-release polymerization strategy precisely governs the formation of poly(ethyl cyanoacrylate) network. Secondary gelation triggered by electrolyte infiltration leads to the effective enhancement of lithium-sulfur batteries.