Synthesis of Li Conductive Polymer Layer on 3D Structured S Cathode by Photo-Polymerization for Li-S Batteries

The dissolution of lithium polysulfide (Li2Sx, 4 <= x <= 8, LiPS) during charge/discharge testing is a critical issue hindering the practical application of lithium-sulfur batteries (LSBs). To suppress LiPS dissolution, we propose a facile method to fabricate a Li-ion-conductive polymer layer by photopolymerization. The electrochemical performance of LSBs was investigated by preparing small pouch cells containing a three-dimensional (3D) structured sulfur-based cathode that either was or was not layered with the new polymer. Analysis of the electrolyte in the LSB pouch cell by UV-Vis spectroscopy revealed that a 3D S cathode with polymer layer shows a good discharge capacity of 535 mA h g(-1) and a coulombic efficiency (CE) of over 96% after 40 cycles. In comparison, the 3D S cathode without a polymer layer has a poor discharge capacity of 389 mA h g(-1) and a CE of over 22% after 40 cycles. The dissolution suppressing ability of our new polymer layer demonstrates promise for the practical application of LSBs. (C) 2022 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.