Tian Liang, Li Li, Ren Zhaowen, Yuan Wenhui
School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, China.
School of Environment and Energy, South China University of Technology, Guangzhou, 510006, China.
Small. 2025 Aug;21(34):e2503389. doi: 10.1002/smll.202503389. Epub 2025 Jul 2.
The quasi-solid-state reaction process in sulfurized polyacrylonitrile (SPAN) has emerged as a promising strategy to mitigate the polysulfide shuttle effect in lithium-sulfur (Li-S) batteries. However, the practical implementation of SPAN cathodes in ether-based electrolytes remains challenging due to solvation-induced structural rearrangement stemming from sluggish redox kinetics. Herein, a hierarchically structured composite (denoted as HSPAN) is developed through pyrolytic transformation of polystyrene (PS) templates coupled with carbon nanotubes (CNTs) network integration. This engineered architecture establishes dual electron-ion transport channels, which synergistically enhance sulfur redox kinetics, suppress short-chain sulfur dissolution, and enable stable charge/discharge cycling in ether electrolytes. The optimized HSPAN cathode delivers a specific discharge capacity of 1145 mAh g⁻¹ at 1 C rate with a sulfur content of 50%, maintaining 82% capacity retention over 800 cycles. Density functional theory (DFT) calculations reveal that the sulfurization treatment significantly narrows the HOMO-LUMO energy gap by modulating the electronic structure of polyacrylonitrile, thereby enhancing the conductivity and redox activity of the material, providing a theoretical basis for designing high-performance lithium-sulfur battery cathodes. This work provides fundamental insights into the solvation dynamics of sulfurized polymers and demonstrates a viable pathway toward practical high-energy-density Li-S batteries through rational electrode engineering.
硫化聚丙烯腈（SPAN）中的准固态反应过程已成为减轻锂硫（Li-S）电池中多硫化物穿梭效应的一种有前景的策略。然而，由于氧化还原动力学迟缓导致溶剂化诱导的结构重排，SPAN阴极在醚基电解质中的实际应用仍然具有挑战性。在此，通过聚苯乙烯（PS）模板的热解转变与碳纳米管（CNTs）网络整合，开发了一种分层结构的复合材料（称为HSPAN）。这种工程结构建立了双电子-离子传输通道，协同增强了硫的氧化还原动力学，抑制了短链硫的溶解，并在醚电解质中实现了稳定的充放电循环。优化后的HSPAN阴极在1 C倍率下，硫含量为50%时，具有1145 mAh g⁻¹的比放电容量，在800次循环中保持82%的容量保持率。密度泛函理论（DFT）计算表明，硫化处理通过调节聚丙烯腈的电子结构，显著缩小了HOMO-LUMO能隙，从而提高了材料的导电性和氧化还原活性，为设计高性能锂硫电池阴极提供了理论依据。这项工作为硫化聚合物的溶剂化动力学提供了基本见解，并通过合理的电极工程展示了一条通往实用高能量密度锂硫电池的可行途径。
