State Key Laboratory of Organic-Inorganic Composites, Center for Fire Safety Materials, Beijing University of Chemical Technology, Beijing, 100029, P. R. China.
Small. 2022 Sep;18(38):e2203693. doi: 10.1002/smll.202203693. Epub 2022 Aug 25.
Lithium-sulfur batteries (LSBs) have attracted extensive attention owing to their high energy density and abundant sulfur resources. However, LSBs are still restricted by the unsatisfactory electrochemical performance resulting from the shuttle effect of lithium polysulfide (LiPSs), and the potential fire hazard caused by inflammable ether electrolytes and polyolefin separators. Herein, a facile immobilization strategy for hexachlorocyclotriphosphazene (HCCP) is creatively applied to address the above issues simultaneously. Insoluble HCCP cross-linked microspheres (H-CMP) are firstly obtained at ambient temperature using tannic acid (TA) as a cross-linking agent and then a multifunctional separator coating is constructed based on H-CMP. The released phosphorus-related radicals from H-CMP in wide temperatures effectively prevent the combustion of electrolytes and separators, and hence improve the fire safety of the Li-S pouch cell. Furthermore, H-CMP availably chemisorbs LiPSs to interdict the shuttle effect, thereby dramatically improving the electrochemical performance of LSBs. The effectiveness of this strategy is also verified in high sulfur loading (6.38 mg cm ), high temperature (50 °C), and Li-S pouch cells. More importantly, H-CMP exhibits sufficient stability for Li metal and suppression of Li dendrites. This facile immobilization strategy for multifunctional phosphazenes provides a competitive option for the large-scale fabrication of high-safety and high-performance LSBs.
锂硫电池（LSB）因其高能量密度和丰富的硫资源而受到广泛关注。然而，LSB 仍然受到多硫化锂（LiPSs）的穿梭效应以及易燃醚电解质和聚烯烃分离器引起的潜在火灾危险的限制。在此，我们创造性地应用了一种六氯环三磷腈（HCCP）的简单固定化策略来同时解决上述问题。首先，使用单宁酸（TA）作为交联剂，在室温下获得不溶性 HCCP 交联微球（H-CMP），然后基于 H-CMP 构建多功能分离器涂层。H-CMP 在较宽温度范围内释放出的磷相关自由基可有效阻止电解质和分离器的燃烧，从而提高 Li-S 软包电池的防火安全性。此外，H-CMP 有效地化学吸附 LiPSs 以阻止穿梭效应，从而显著提高 LSB 的电化学性能。该策略在高硫载量（6.38mg cm）、高温（50°C）和 Li-S 软包电池中也得到了验证。更重要的是，H-CMP 对锂金属表现出足够的稳定性和抑制枝晶生长的能力。这种用于多功能磷腈的简单固定化策略为大规模制造高安全性和高性能 LSB 提供了一种有竞争力的选择。
