An optimal carbon fiber interlayer integrated with bio-based gel polymer electrolyte enabling trapping-diffusion-conversion of polysulfides in lithium-sulfur batteries

The shuttle effect of the highly soluble lithium polysulfides (LiPSs) has hampered the widespread use of lithium-sulfur (Li-S) batteries in various high performance energy-storage devices. Herein, an optimum carbon fiber interlayer integrated with bio-based gel polymer electrolyte (GPE) was designed for enabling trapping-diffusion-conversion of LiPSs. The interlayer was obtained through simple calcination of commercial carbon textile (CT), which can physically block LiPSs and permit the good diffusion of Li ion. The calcined CT containing polar groups derived from sizing agent can not only chemically bond LiPSs, but also promote electron transport and provide more redox reaction sites to reactivate the immobilized LiPSs, owing to high conductivity of the exposed carbon fibers. Moreover, a perfect combination was achieved that the biodegradable nanofiber membrane for preparing GPEs with high ionic conductivity was directly electrospun on the optimal CT (OCT-GPE). The GPE can further suppress the LiPSs shuttle and the abundant amide groups of soy protein isolate in GPE can effectively anchor LiPSs. Consequently, the Li-S batteries involving OCT-GPE showed a great improvement in the cycling stability and rate performance compared with those of the cells based on commercial Celgard 2400. This work will be quite illuminating to design novel interlayer and polymer electrolyte for high-performance Li-S batteries.