Institute for Frontier Materials , Deakin University , Geelong and Waurn Ponds, Victoria 3216 , Australia.
ACS Appl Mater Interfaces. 2019 Oct 9;11(40):36705-36716. doi: 10.1021/acsami.9b12395. Epub 2019 Sep 24.
Based on the urgent demand of non-flammable electrospun nanofiber separators and the strong adsorption to polysulfides through chemical doping in separators for Li-S cell, in this study, a phosphorus, nitrogen, and sulfur three-flame retardant (di-(2-(5,5-dimethyl-2-sulfido-1,3,2-dioxaphosphinan-2-yl)hydrazineyl)--ethylphosphinic) was synthesized and a high-performance flame-retarding poly--phenyleneisophthalamide (PMIA) membrane was successfully prepared through blend electrospinning with the flame retardant, it is regarded as a promising gel nanofiber membrane with advanced safety for the lithium-sulfur (Li-S) cell, and it was systematically explored and analyzed. It was presented that the modified PMIA electrospun membrane with the synthesized flame retardant possessed excellent flame retardation, outstanding thermal stability, and good mechanical strength. Meanwhile, the prepared membrane showed extraordinarily high uptake and preserving retention of the liquid electrolyte and enhanced ionic conductivity. More importantly, the assembled Li-S cells using the obtained membrane exhibited excellent cycling retention and outstanding rate capability because of its fast ion transportation and good interfacial compatibility. The assembled batteries with the novel membrane exhibited a high first-cycle discharge capacity of 1121.50 mA h g, superior discharge capacity retention of 713.41 mA h g, and high Coulombic efficiency of 98.46% after 600 cycles at the 0.5 C rate. In addition, the limiting oxygen index of the obtained nanofiber membrane with flame retardancy was as high as ∼30.0%, which could greatly enhance the safety of the electrospun nanofiber separator. The excellent electrochemical performances and safety for the battery assembled with the prepared gel PMIA nanofiber membrane were attributed to the significantly prevented "shuttle effect" of lithium polysulfides based on the physical capturing of lithium polysulfides through the obtained jelly-like gel state and chemical binding of polysulfide intermediates through the tridoped phosphorus, nitrogen, and sulfur elements in the PMIA and the flame retardant. All of these excellent properties will promote the great development of the Li-S battery with high performance and satisfactory safety.
基于对不可燃电纺纳米纤维分离器的迫切需求，以及通过化学掺杂在 Li-S 电池的分离器中对多硫化物的强烈吸附，本研究合成了一种磷、氮、硫三阻燃剂（双-（2-（5,5-二甲基-2-硫代-1,3,2-二氧杂磷杂环戊烷-2-基）肼基）乙基膦酸），并通过共混静电纺丝成功制备了一种高性能阻燃聚-对苯二甲酰间苯二胺（PMIA）膜，该膜被认为是一种很有前途的用于锂硫（Li-S）电池的先进安全凝胶纳米纤维膜，并对其进行了系统的探索和分析。结果表明，用合成阻燃剂改性的 PMIA 电纺膜具有优异的阻燃性、出色的热稳定性和良好的机械强度。同时，所制备的膜表现出极高的液体电解质吸收和保持能力以及增强的离子导电性。更重要的是，由于其快速的离子传输和良好的界面相容性，组装的 Li-S 电池具有出色的循环保留率和卓越的倍率性能。使用获得的膜组装的电池在 0.5 C 倍率下循环 600 次后，具有 1121.50 mA h g 的高首次放电容量、713.41 mA h g 的优异放电容量保持率和 98.46%的高库仑效率。此外，具有阻燃性的所得纳米纤维膜的极限氧指数高达约 30.0%，这可以大大提高电纺纳米纤维分离器的安全性。由于基于获得的凝胶状凝胶状态物理捕获锂离子多硫化物和 PMIA 和阻燃剂中的三掺杂磷、氮、硫元素化学结合多硫化物中间体，显著阻止了“穿梭效应”，组装的电池具有出色的电化学性能和电池安全性。所有这些优异的性能将促进具有高性能和令人满意安全性的 Li-S 电池的巨大发展。
