Integrated Cathode Design for Polysulfide Limitation and Kinetic Enhancement Enabled by In Situ Intermittently Encapsulating Sulfur with Poly(ionic liquid).

Although lithium-sulfur (Li-S) batteries are promising next-generation energy storage devices, polysulfide shuttling and electrode volume deformation remain challenges for their practical applications. Herein, a groundbreaking modification strategy is proposed that leverages an integrated cathode design to synchronously restrict polysulfide shuttling and enhance electrochemical kinetics. Specifically, the poly(ionic liquid) termed VIBM with high ionic conductivity is in situ intermittently encapsulated on S surface, which effectively facilitates Li+ transport and ensures free electron transfer stemming from sufficient contact between exposed S area and conductive agents. As a result, polysulfides are physically and chemically confined within cathode region, while electrochemical reaction kinetics are enhanced. Moreover, the highly flexible VIBM coating can accommodate electrode volume fluctuations. The resulting Li-S cells demonstrate exceptional cycling durability and rate capability with reduced self-discharge behavior. This innovative cathode encapsulation strategy opens a new path for addressing "shuttle effect", thus promoting the development of Li-S batteries.