Park Hyeona, Kang Hyokyeong, Kim Hyerim, Kansara Shivam, Allen Jan L, Tran Dat, Sun H Hohyun, Hwang Jang-Yeon
Department of Energy Engineering, Hanyang University, Seoul 04763, Republic of Korea.
Battery Science Branch, US DEVCOM Army Research Laboratory, 2800 Powder Mill Rd, Adelphi, Maryland 20783-1197, United States.
ACS Appl Mater Interfaces. 2023 Oct 4;15(39):45876-45885. doi: 10.1021/acsami.3c08876. Epub 2023 Sep 19.
Among lithium-sulfur (Li-S) battery materials, sulfurized polyacrylonitrile (SPAN) has attracted substantial attention as a cathode material owing to its potential to bypass the problematic polysulfide formation and shuttling effect. Carbonate-based electrolytes have been eschewed compared with ether-based electrolytes because of their poor compatibility with Li metal anodes. In this work, we design and study an electrolyte comprising 0.8 M of lithium bis(trifluoromethanesulfonyl)imide, 0.2 M of lithium difluoro(oxalate)borate, and 0.05 M of lithium hexafluorophosphate in ethyl methyl carbonate/fluoroethylene carbonate = 3:1 v/v solution in the Li-S battery coupled with a Li metal anode and SPAN cathode. The well-designed carbonate-based electrolyte effectively stabilizes both electrodes, delivering high Coulombic efficiencies with stable cyclability. Studies using optical microscopy and atomic force microscopy demonstrate that dense, uniform Li deposition is promoted to suppress dendrite growth even at a high current density. Raman spectroscopy reveals a reversible Li storage behavior in the SPAN structure through the cleavage of disulfide bonds and their redimerization during lithiation and delithiation. As a result, the proposed Li-S battery delivers an overall capacity retention of 73.5% over 1000 cycles, with high Coulombic efficiencies over 99.9%.
在锂硫（Li-S）电池材料中，硫化聚丙烯腈（SPAN）作为一种阴极材料受到了广泛关注，因为它有可能避免有问题的多硫化物形成和穿梭效应。与醚基电解质相比，碳酸盐基电解质因其与锂金属阳极的相容性差而被摒弃。在这项工作中，我们设计并研究了一种电解质，它由0.8 M双（三氟甲磺酰）亚胺锂、0.2 M二氟（草酸）硼酸锂和0.05 M六氟磷酸锂组成，溶解于碳酸甲乙酯/氟代碳酸乙烯酯=3:1 v/v的溶液中，用于Li-S电池，该电池配有锂金属阳极和SPAN阴极。精心设计的碳酸盐基电解质有效地稳定了两个电极，提供了高库仑效率和稳定的循环性能。使用光学显微镜和原子力显微镜的研究表明，即使在高电流密度下，致密、均匀的锂沉积也能得到促进，从而抑制枝晶生长。拉曼光谱揭示了在锂化和脱锂过程中，SPAN结构中通过二硫键的断裂及其重新二聚化实现了可逆的锂存储行为。结果，所提出的Li-S电池在1000次循环中总体容量保持率为73.5%，库仑效率超过99.9%。
