A multi-functional binder for high loading sulfur cathode

Lithium sulfur (Li-S) batteries are the promising power sources, but their commercialization is significantly impeded by poor energy-storage functions at high sulfur loading. Here we report that such an issue can be effectively addressed by using a mussel-inspired binder comprised of chitosan grafted with catecholic moiety for sulfur cathodes. The resulting sulfur cathodes possess a high loading up to 12.2 mg cm⁻² but also exhibit one of the best electrochemical properties among their counterparts. The excellent performances are attributed to the strong adhesion of the binder to sulfur particles, conducting agent, current collector, and polysulfide. The versatile adhesion effectively increases the sulfur loading, depresses the shuttle effect, and alleviates mechanical pulverization during cycling processes. The present investigation offers a new insight into high performance sulfur cathodes through a bio-adhesion viewpoint.