High-conductivity free-standing Li6PS5Cl/poly(vinylidene difluoride) composite solid electrolyte membranes for lithium-ion batteries

Bulk-type all-solid-state batteries (ASSBs) using sulfide solid electrolyte are considered as a promising alternative to commercial lithium-ion batteries owing to their high energy density and safety. However, cell energy density is often comparatively low due to use of a thick solid electrolyte separator and a lithium alloy as anode. For achieving high-performance ASSBs, creating a thin free-standing electrolyte with high-conductivity and good cycling stability against lithium anode is essential. In this work, we present Li6PS5Cl/poly(vinylidene difluoride) (LPSCl/PVDF) composite electrolytes prepared by a slurry method. The influence of the PVDF content on the microstructure, morphology, ionic conductivity and activation energy of the LPSCl/PVDF electrolytes is systematically investigated. Free-standing LPSCl/PVDF membranes with a thickness of 100-120 mu m and a high ionic conductivity of about 1.10(-3) S cm(-1) at 25 degrees C are obtained. After adding PVDF to the LPSCl electrolyte, the cycling stability of the LPSCl electrolyte against lithium metal improves significantly. Therefore, LPSCl/PVDF composite electrolytes are promising candidates to be used in ASSBs. (c) 2020 The Chinese Ceramic Society. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).