Selective chemisorption of polysulfides by porous molecular crystal: Cathode host materials for lean-electrolyte lithium-sulfur cells with high electrochemical stability
Selective chemisorption of polysulfides by porous molecular crystal: Cathode host materials for lean-electrolyte lithium-sulfur cells with high electrochemical stability
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DOI：
10.1016/j.jpowsour.2023.232891
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发表时间：
2023-05
影响因子：
9.2
通讯作者：
Yin-Ju Yen;Teng‐Hao Chen;Yao‐Ting Wang;Alexandra Robles;Miloš Đerić;O. Miljanić;Watchareeya Kaveevivitchai;Sheng‐Heng Chung
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文献类型：
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作者：
Yin-Ju Yen;Teng‐Hao Chen;Yao‐Ting Wang;Alexandra Robles;Miloš Đerić;O. Miljanić;Watchareeya Kaveevivitchai;Sheng‐Heng Chung
开发具有多孔基底材料的高能量密度锂硫电池通常会遇到多硫化物的易容纳性和快速电解质吸收之间的折衷。多孔分子晶体（PMCs）是一类由离散的小分子通过弱相互作用组装而成的新型有机多孔材料，近年来在储能方面显示出巨大的潜力。环苯偶姻酯（CE）是一种具有高羰基含量的多孔结构的PMC。在这项研究中，我们利用CE作为有效的硫宿主的独特吸附特性来设计具有优异电化学稳定性的贫电解质锂硫电池。CE的多孔性和极性羰基为多硫化物提供了优异的化学吸附平台，同时也使电解质能够顺利渗透。因此，我们的硫-环安息香酯（硫-CE）储能材料以低电解质与硫的比率达到严格的电池设计参数（4 μL mg−1）和高硫负载/含量（4 mg cm-2和80wt%），但表现出优异的电化学特性，包括907 mA h g-1的出色放电容量，200次循环的循环能力，和从C/20到1C的高倍率性能。这项研究开辟了一种新的选择性化学吸附策略，同时优化贫电解质锂硫电池，同时具有高活性材料负载和高电池稳定性。
The development of high-energy-density lithium-sulfur batteries with porous substrate materials often meets the compromise between the facile accommodation of polysulfides and the fast electrolyte absorption. Porous molecular crystals (PMCs), a new class of organic porous materials assembled by discrete small moleculesviaweak intermolecular interactions, recently show their potential in energy storage. Cyclobenzoin ester (CE), as one of PMCs, features a high abundance of carbonyl groups as a porous molecule. In this study, we utilize the unique adsorption characteristics of CE as an effective sulfur host to design lean-electrolyte lithium-sulfur cells with excellent electrochemical stability. The porosity and polar carbonyl groups of CE provide an excellent chemisorption platform for polysulfides, while also enabling smooth electrolyte penetration. As a result, our sulfur-cyclobenzoin ester (sulfur-CE) energy storage material attains rigorous cell-design parameters with a low electrolyte-to-sulfur ratio (4 μL mg−1) and a high sulfur loading/content (4 mg cm−2and 80 wt%), yet exhibits excellent electrochemical characteristics, including an outstanding discharge capacity of 907 mA h g−1, cyclability of 200 cycles, and a high rate performance from C/20 to 1C. This research opens a new strategy of selective chemisorption for simultaneously optimizing lean-electrolyte lithium-sulfur cells with both high active-material loadings and high cell stability.