A polysulfides adsorption strategy through cation-anion interactions for achieving high-safety lithium-sulfur batteries in multiple scenarios
writer：Xinxin Dong，Xin Tong
keywords：Lithium-sulfur battery, Coating for sparator, Boron nitride, Redox kinetic, Fire safety
source：期刊
Issue time：2024年
The widespread application of lithium-sulfur batteries (LSBs) is hindered by challenges such as the shuttle effect of polysulfides (LiPSs), slow reaction kinetics, and fire safety concerns. In this study, surface-functionalized boron nitride nanosheets (ChBN) are prepared and employed as functional separator coatings, enabling multiple application scenarios of LSBs. Specifically, a creative strategy of cation-anion interactions is constructed through the strong chemisorption of N on the ChBN surface to S+n- in LiPSs. In addition, the boron nitride and N show synergistic effects on adsorption-catalysis, further facilitating the rapid and sufficient deposition of Li+2S. The prepared LSBs with ChBN + SP/PP separators exhibit excellent cycle stability (an ultralow capacity degradation of 0.034 % per cycle over 500 cycles at 2C). These LSBs are available in a wide temperature range of ?20 to 60 °C, offering a capacity of 1208 mA h/g at 60 °C and 919 mA h/g at ?20 °C. Furthermore, the presence of ChBN effectively improves the fire-safety of pouch batteries through the condensed-phase flame retardant mechanism. This simple fabrication process of ChBN is effective and favorable for large-scale manufacturing, which provides a feasible method for the development of high-safety LSBs.
锂硫电池（LSB）的广泛应用受到多硫化物（LiPS）的穿梭效应、缓慢反应动力学和消防安全问题等挑战的阻碍。在这项研究中，制备了表面功能化的氮化硼纳米片（ChBN），并将其用作功能性隔膜涂层，实现了LSB的多种应用场景。具体而言，通过N在ChBN表面对LiPSs中S+n-的强化学吸附，构建了一种创新的阳离子-阴离子相互作用策略。此外，氮化硼和氮对吸附催化显示出协同作用，进一步促进了Li+2S的快速和充分沉积。制备的具有ChBN+SP/PP隔膜的LSB具有优异的循环稳定性（在2C下500次循环中，每次循环的超低容量退化为0.034%）。这些LSB可在-20至60°C的宽温度范围内使用，在60°C时的容量为1208 mA h/g，在-20°C时为919 mA h/g。此外，ChBN的存在通过凝聚相阻燃机制有效地提高了袋式电池的防火安全性。这种简单的ChBN制造工艺是有效的，有利于大规模制造，为开发高安全性的LSB提供了一种可行的方法。