Enhanced Cycling Performance of All-Solid-State Li-S Battery Enabled by PVP-Blended PEO-Based Double-Layer Electrolyte

Despite the high specific capacity of Li-S battery, shuttle effect of lithium polysulfides (LiPSs) and safety issue pose a great challenge to realize its commercial application. Replacing liquid electrolyte with poly (ethylene oxide) (PEO) -based solid-state electrolyte is considered as a promising method to boost the safety, but the shuttle effect of LiPSs cannot be completely eliminated. In this work, a new kind of double-layer PEO-based polymer electrolyte is designed to restrict the LiPSs. The layer next to cathode consists of PEO and poly(vinylpyrrolidone) (PVP). The other layer consists of PEO. PVP with abundant of amide groups has been proved to have strong affinity to LiPSs. The strong interaction between LiPSs and carbonyl groups in amide is verified by Attenuated Total Reflection-Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy tests. As a result, the assembled Li-S battery exhibits a specific capacity of 1100 mAh g