Qu Dejie, Liu Tao, Sun Youlong, Yan Yuewei, Li Chuanchuan, Cui Zili, Gao Chuanwei, Kong Shuaice, Zhang Zengqi, Liu Zhiming, Zhang Shu, Wang Shitao, Lv Zhaolin, Xu Gaojie, Li Guicun, Cui Guanglei
College of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, 266042, P. R. China.
Qingdao Industrial Energy Storage Research Institute, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, P. R. China.
Adv Mater. 2025 Jul 21:e05762. doi: 10.1002/adma.202505762.
Lithium-sulfur (Li-S) batteries represent a compelling next-generation energy storage system with practical energy densities exceeding 700 Wh kg, offering a promising pathway beyond current lithium-ion technology. However, their commercial viability remains constrained by deleterious interfacial reactions between lithium metal anodes and polysulfide-containing electrolytes. Herein, it is presented a molecular engineering approach through a novel boron-based salt, lithium perfluoropinacolatoborate (LiFPB), strategically designed to reinforce the solid electrolyte interphase (SEI) for long-cycling Li-S batteries. LiFPB anions, featuring higher specific charge (mass-to-charge ratio) and larger steric bulk compared to conventional salts, demonstrate enhanced resistance to Helmholtz double-layer repulsion and increased susceptibility to lithium metal reduction, promoting the formation of a robust SEI enriched with LiF and LiBO species. The LiFPB-containing electrolyte exhibits superior lithium metal compatibility, achieving a high coulombic efficiency of 99.59%. Consequently, Li-S cells demonstrate markedly improved capacity retention from 50.9% to 75.7% over 200 cycles. This strategy has been successfully scaled to Ah-level Li-S pouch cells, achieving practical energy densities of 408 Wh kg with stable cycling over 75 cycles. This work presents an effective approach to developing long-cycling Li-S batteries through the rational design of electrolyte salt.
锂硫（Li-S）电池是一种极具吸引力的下一代储能系统，其实际能量密度超过700 Wh/kg，为超越当前锂离子技术提供了一条有前景的途径。然而，它们的商业可行性仍然受到锂金属负极与含多硫化物电解质之间有害界面反应的限制。在此，我们提出了一种分子工程方法，通过一种新型的硼基盐——全氟频哪醇硼酸锂（LiFPB），其经过精心设计，旨在增强长循环Li-S电池的固体电解质界面（SEI）。与传统盐相比，LiFPB阴离子具有更高的比电荷（质量电荷比）和更大的空间体积，表现出对亥姆霍兹双层排斥的增强抗性以及对锂金属还原的更高敏感性，促进了富含LiF和LiBO物种的坚固SEI的形成。含LiFPB的电解质表现出优异的锂金属兼容性，实现了99.59%的高库仑效率。因此，Li-S电池在200次循环中显示出容量保持率从50.9%显著提高到75.7%。该策略已成功扩展到Ah级Li-S软包电池，在75次循环中实现了408 Wh/kg的实际能量密度和稳定循环。这项工作通过合理设计电解质盐，提出了一种开发长循环Li-S电池的有效方法。
