Enhancing Li-S battery performance via functional polymer binders for polysulfide inhibition

The commercialization of lithium-sulfur (Li-S) batteries faces several challenges, including poor conductivity, unexpected volume expansion, and continuous sulfur loss from the cathode due to redox shuttling. In this study, we introduce a novel polymer via a simple cross-linking between poly(ether-thioureas) (PETU) and poly(3,4-ethylenedioxythiophene)- poly(styrenesulfonate) (PEDOT:PSS) as a bifunctional binder for Li-S batteries (devotes as “PPTU”). Compared to polyvinylidene fluoride (PVDF), as-prepared PPTU exhibits significantly higher electrical conductivity, facilitating electrochemical reactions. Additionally, PPTU demonstrates effective adsorption of lithium polysulfides, leading to improved cycling stability by suppressing the shuttling effect. We investigate this behavior by monitoring morphological changes at the cell interface using synchrotron X-ray tomography. Cells with PPTU binders exhibit remarkable rate performance, desired reversibility, and excellent cycling stability even under stringent bending and twisting conditions. Our work represents promising progress in functional polymer binder development for Li-S batteries.