In Operando FTIR Study on the Effect of Sulfur Chain Length in Sulfur Copolymer-Based Li–S Batteries
In Operando FTIR Study on the Effect of Sulfur Chain Length in Sulfur Copolymer-Based Li–S Batteries
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DOI：
10.1021/acs.jpcc.1c09124
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发表时间：
2022-07
期刊：
影响因子：
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通讯作者：
A. Rafie;Rhyz Pereira;A. A. Shamsabadi-A.;V. Kalra
中科院分区：
文献类型：
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作者：
A. Rafie;Rhyz Pereira;A. A. Shamsabadi-A.;V. Kalra
利用逆硫化反应合成富硫共聚物是改性硫活性材料以增强锂硫电池稳定性的实用方法。然而，为了有效地设计此类聚合物，彻底了解潜在的氧化还原机制至关重要。在这里，我们使用具有衰减全反射的操作FTIR光谱研究富硫共聚物的电化学行为。我们使用硫-二异丙烯基苯共聚物[聚(S-co-DIB)]作为Li-S电池的活性材料，并监测放电和充电过程中不同电位下C-S峰位置的演变以及S-S键拉伸的循环变化。此外，我们合成了硫重量百分比为80和30重量％的各种共聚物，并比较了循环伏安扫描期间的电化学行为及其相应的红外响应。我们的结果表明，硫共聚物中的 C-S 键在锂硫电池的电压窗口中不活跃。此外，我们发现随着单体重量百分比的增加，C-S 峰位置的偏移变得更小。此外，当硫重量%从80重量%减少到30重量%时，~500 cm-1处的S-S拉伸峰减弱，这凸显了共聚物电化学行为的显着变化。
Synthesis of sulfur-rich copolymers using the inverse vulcanization reaction is a practical approach to modify the sulfur active material for enhanced stability in Li–S batteries. However, to effectively design such polymers, a thorough understanding of the underlying redox mechanisms is critical. Here, we study electrochemical behavior of sulfur-rich copolymers usingin operandoFTIR spectroscopy with attenuated total reflection. We used sulfur-diisopropenylbenzene copolymers [poly(S-co-DIB)] as the active material in Li–S batteries and monitored the evolution of the C–S peak position and cyclic changes in the S–S bond stretching at different potentials during discharge and charge. Moreover, we synthesized various copolymers with sulfur wt % of 80 and 30 wt % and compared the electrochemical behavior and their corresponding IR response during cyclic voltammetry sweep. Our results indicated that the C–S bond in sulfur copolymers is not active in the voltage window of Li–S batteries. Moreover, we showed that the shift in the C–S peak position becomes smaller with increase in the monomer wt %. In addition, the S–S stretching peak at ∼500 cm–1diminishes when the sulfur wt % is decreased from 80 to 30 wt %, highlighting a significant change in electrochemical behavior of the copolymers.