Soy protein isolate/MXene decorated acidified carbon paper interlayer for long-cycling Li-S batteries

The terrible shuttling of lithium polysulfides (LiPSs) is a major obstacle for commercializing lithium-sulfur (Li-S) batteries as high-performance energy storage systems. In this study, a carbon-based interlayer with effective suppression capability on the shuttle effect is developed by simply coating a well-dispersed mixture of soybean protein isolate/MXene onto the acidified carbon paper (ACP). The resultant composite interlayer (SM@ACP) is able to synergistically diminish the shuttle effect through chemical adsorption and physical blocking. Meanwhile, this interlayer displays excellent conductivity and facilitates the diffusion of Li ions due to the composite coating to promote both electron/ion conduction as well as the porous structure of ACP. Benefiting from the unique properties of the composite interlayer, the as-assembled Li-S batteries with SM@ACP interlayers show a great improvement in the cycling stability and rate performance, delivering a very low-capacity decay rate of 0.071% per cycle at 0.5 C even after 800 cycles. This work provides a feasible route to realize rational design and commercial mass production of desirable interlayers for promoting the commercialization of Li-S batteries.