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摘要
锂硫(Li-S)电池作为下一代储能系统的候选者之一,具有高能量密度的优势。然而,多硫化锂(LiPSs)中间体缓慢的氧化还原动力学很大程度上阻碍其实际应用。通过引入电解液添加剂2,5-二巯基-1,3,4-噻二唑(DMcT)调节了LiPSs的分子轨道能级,以提高Li-S电池的电化学性能。原位锂化的DMcT(DMcT2-)和LiPSs通过可逆的离子-偶极作用实现结合,形成配位化合物。与LiPSs相比,配位化合物具有更高的最高占据分子轨道(HOMO)能级和更低的最低占据分子轨道(LUMO)能级,因此表现出更强的氧化还原活性。采用DMcT的Li-S电池不仅在2C倍率下提供703mA·h/g的容量,在0.2C倍率下100次循环后仍保持768mA·h/g的比容量。
Abstract
Lithium-sulfur (Li-S) batteries,as one of the candidates for next-generation energy storage systems,have the advantage of high energy density.However,the slow redox kinetics of lithium polysulfide (LiPSs) intermediates largely hinder their practical application.Here,we modulated the molecular orbital energy levels of LiPSs by introducing electrolyte additive 2,5-dimercapto-1,3,4-thiadiazole (DMcT) to improve the electrochemical performance of Li-S batteries.In-situ lithiated DMcT (DMcT2-) and LiPSs were bound through reversible ion-dipole interaction to form coordination compounds.Compared with LiPSs,the coordination compounds had higher highest occupied molecular orbital (HOMO) energy levels and lower lowest unoccupied molecular orbital (LUMO) energy levels,thus exhibiting stronger redox activity.Li-S batteries with DMcT not only provided a capacity of 703mA·h/g at 2C,but also maintained a capacity of 768mA·h/g after 100 cycles at 0.2C.
关键词
2,5-二巯基-1,3,4-噻二唑
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多硫化锂
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动力学
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锂硫电池
Key words
2,5-dimercapto-1,3,4-thiadiazole
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lithium polysulfide
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kinetics
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lithium-sulfur battery
一种加速多硫化锂转化动力学的Li-S电池添加剂研究[J].
化工新型材料, 2024, 52(6): 173-176 DOI:10.19817/j.cnki.issn1006-3536.2024.06.027
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基金资助
国家自然科学基金(51273027);2022年江苏省研究生科研与实践创新计划(KYCX22＿3095)
