均相氧化还原介质可以有效缓解多硫化锂在锂硫电池中的穿梭效应和缓慢的氧化还原动力学，但由于多硫化锂的多步转化需要串联催化的多功能活性位点，因此无法实现多硫化物锂的完美性能。
近日，西安交通大学唐伟教授、东南大学吴宇平教授和四川大学张千玉副研究员等人在Science China Materials发表研究论文，基于氧化还原共介导原理，提出了一种混合有机二硒化物和有机二碲化物（混合-Se/Te）的促进剂，以诱导串联催化并提升多硫化锂的有效电化学转化。
本文要点
1) 二苯二硒化物促进了多硫化锂与硫之间的固-液和液-液转化，而二苯二碲化物则改善了硫化锂沉积的固-液转化。2) 即使在6.5 mg cm−2的高硫负载和5.88 μL mg−1的低电解液/硫比下，10 mM的低浓度混合-Se/Te促进剂也提供了6.6 mAh cm−2的高放电容量和在0.5 C下4.1 mAh cm−2的良好倍率性能。3) 组装的1.5 Ah级锂硫软包电池在0.05 C时提供了332 Wh kg−1的能量密度和良好的循环稳定性。本研究展示了利用分离活性位点推动连续硫转化反应的适用性，并预计将激发针对能量相关氧还原反应的动力学促进剂的深度分子设计。Figure 1. Tactics to address shuttling effect of soluble LiPSs: (a) physical confine, (b) chemical anchor, and (c) redox comediation methods. (d) Mechanism diagram showing DPDSe and DPDTe coRMs with tandem conversion of LiPSs.Figure 2. Electrochemical performance of Li-S batteries comediated by DPDTe/ DPDSe: (a) Charge/discharge curves at 0.2 C, (b) rate performance, (c) charge/discharge curves at 4 C, (d) cycling performance at 0.2 C, (e) long cycling performance at 1 C, (f) the SEM images of cycled cathode and cycled anode and (g) cycling performance at 0.2 C of Li-S batteries under high sulfur loading and lean electrolyte usage comediated by DPDTe/ DPDSe.![]()
Figure 3. (a) CV profiles for the Blank, w/DPDTe and w/DPDSe cells. (b) CV profiles and (c) EIS spectra of Li2S6 symmetrical cells with or without DPDTe and DPDSe. (d) Potentiostatic discharge curves of Li||Li2S8, Li||DPDTe + Li2S8 and Li||DPDSe + Li2S8 cells. The SEM image of deposited Li2S in (e) Li||DPDTe + Li2S8 and (f) Li||DPDSe + Li2S8 cells. (g) Li2S dissolution profiles of Li||Li2S8, Li||DPDTe + Li2S8 and Li||DPDSe + Li2S8 cells. Raman spectra of discharge process of (h) w/DPDTe cells and (i) w/DPDSe cells. (j) LUMO and HOMO energy levels of various Li2Sn and LiPhSeSn, n = 8, 6, or 4. The sulfur, selenium, tellurium carbon, hydrogen, and lithium atoms were labeled with yellow, brown, orange, gray, white, and blue, respectively. The cyan and yellow areas denoted the positive and negative sections of the LUMO and HOMO isosurface, respectively.![]()
Figure 4. Electrochemical performance of high-sulfur-loading Li-S batteries comediated by 10 mM mixed-Se/Te coRMs: (a) charge/discharge curves at 0.2 C, (b) rate performance, (c) charge/discharge curves at 0.1 and 4 C, (d) cycling performance at 0.2 C, and (e) long cycling performance at 1 C. Electrochemical performance of Li-S pouch cells with high sulfur loading of 5 mg cm−2 and E/S ratio of 3.5 µL mg−1 mediated by mixed-Se/Te: (f) the calculated energy density, (g) cycling performance at 0.05 C, and (h) corresponding charge/discharge curves at different cycles at 0.05 C.Jiangqi Zhou, Chengyong Shu, Qianyu Zhang, Wei Tang, Yuping Wu. Tandemly promoting the sulfur redox kinetics through low concentration mixed organodiselenide and organoditelluride in Ah-level high-energy-density Li-S batteries. Sci. China Mater. (2024).https://doi.org/10.1007/s40843-024-3173-9
![]()
点击左下角“阅读原文”，阅读以上文章PDF原文
![]()
