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Lithium-sulfur batteries (LSBs) are currently considered as a promising candidate for nextgeneration energy storage technologies. However, their practical application is hindered by a critical issue of polysulfide-shuttle. Herein, we present a metal organic framework (MOF) -derived solid electrolyte to address it. The MOF solid electrolyte is developed based on a UIO (Universitetet i Oslo) structure. By grafting a lithium sulfonate (-SO 3 Li) group to the UIO ligand, both the ionic conductivity and the polysulfide-suppression capability of the resulting UIOSLi solid electrolyte are greatly improved. After integrating a Li-based ionic liquid (Li-IL), LiTFSI in 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM [TFSI]), the resulting Li-IL/UIOSLi solid electrolyte exhibits an ionic conductivity of 3.3 × 10 -4 S cm -1 at room temperature. Based on its unique structure, This article is protected by copyright. All rights reserved. 2the Li-IL/UIOSLi solid electrolyte effectively restrains the polysulfide shuttle and suppress lithium dendritic-growth. Lithium-sulfur cells with the Li-IL/UIOSLi solid electrolyte and a Li 2 S 6 catholyte show stable cycling performance that preserve 84% of the initial capacity after 250 cycles with a capacity-fade rate of 0.06% per cycle.

Lithium−sulfur batteries (LSBs) are of great interest as a promising energy storage device because of their high theoretical capacity and energy density. However, they exhibit poor discharge capacity and capacity retention during long-term cycling because of their inherent drawbacks including the poor conductivity of sulfur and lithium sulfide, the shuttle effect of lithium polysulfides (LiPSs), and the large volume expansion of sulfur to lithium sulfide. An effective approach that can solve these problems is to use an interlayer inserted between the separator and the cathode. Nevertheless, the underlying adsorption mechanism of LiPSs on the interlayer has not yet been widely investigated. Herein, the effect of lithium bond chemistry on the adsorption of LiPSs on the functionalized carbon fiber paper (CFP) interlayer containing hydroxyl, carboxyl, or amide functional groups is investigated by a density functional theory approach. It is found that the functionalized CFP exhibits a strong lithium bond interaction between the Li electron acceptor of LiPSs and the N or O electron donor of the functionalized CFP interlayer. In addition, the correlation between the adsorption energy of LiPSs on the interlayer and the electrochemical performance of LSBs is investigated. The results provide the fundamental understanding of the structure−property relationship for the adsorption of LiPSs on the functional groups of the interlayer, which will be beneficial for the further development of advanced LSBs.

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