Huang Dequan, Liang Yi, Wei Tao, Yin Guangda, Zhou Yangtao, Hu Sijiang, Pan Qichang, Zheng Fenghua, Li Qingyu, Chen Yuanhua, Wang Hongqiang
College of Automotive Engineering, Guilin University of Aerospace Technology, Guilin 541004 Guangxi, China.
Guangxi Key Laboratory of Low Carbon Energy Materials, Guangxi New Energy Ship Battery Engineering Technology Research Center, Guangxi Scientific and Technological Achievements Transformation Pilot Research Base of Electrochemical Energy Materials and Devices, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin 541004 Guangxi, China.
J Colloid Interface Sci. 2025 Jul 15;690:137300. doi: 10.1016/j.jcis.2025.137300. Epub 2025 Mar 10.
Lithium metal batteries (LMBs) employing high-voltage cathode present a promising pathway toward high-energy-density energy storage systems. However, critical challenges have hindered their practical application, including lithium dendrite proliferation, unstable solid-electrolyte interphase (SEI), and limited oxidative stability of conventional 1,2-dimethoxyethane (DME)-based electrolytes. Herein, we rationally design a siloxane-based electrolyte system featuring enhanced oxidative stability through solvent molecular engineering. The Si-O bonding in siloxanes demonstrates superior bond energy compared to conventional C-O bonds in DME, which enables remarkable oxidative stability and the compatibility of high-voltage LMBs. Through in-operando Raman spectroscopy and molecular dynamics simulations, we reveal that more FSI anion coordinates with Li to construct the solvation sheath in siloxane-based electrolyte. This unique coordination environment facilitates anion-derived SEI formation dominated by LiF/LiN inorganic components, effectively suppressing dendrite growth and enhancing interfacial stability. The optimized electrolyte (DMS-3) enables exceptional electrochemical performance: Li||Cu cells achieve a high Coulombic efficiency of 99.4 % for 1000 cycles (0.5 mA cm) and 98.8 % for 800 cycles (1.0 mA cm). Li||LiNiCoMnO full cell with 89.82 % capacity retention after 500 cycles at 1.0 C. The practical validation using 1.2 Ah Li||LiNiCoMnO pouch cell demonstrated 92.26 % capacity retention after 110 cycles (0.3/0.5 C). This work establishes a molecular design paradigm for electrolyte engineering, providing critical insights for developing high-voltage LMBs.
采用高压阴极的锂金属电池（LMBs）为实现高能量密度储能系统提供了一条有前景的途径。然而，一些关键挑战阻碍了它们的实际应用，包括锂枝晶的生长、不稳定的固体电解质界面（SEI）以及传统的基于1,2 - 二甲氧基乙烷（DME）的电解质有限的氧化稳定性。在此，我们通过溶剂分子工程合理设计了一种具有增强氧化稳定性的硅氧烷基电解质体系。与DME中传统的C - O键相比，硅氧烷中的Si - O键具有更高的键能，这使得其具有出色的氧化稳定性以及与高压LMBs的兼容性。通过原位拉曼光谱和分子动力学模拟，我们发现更多的FSI阴离子与Li配位，在硅氧烷基电解质中构建溶剂化鞘层。这种独特的配位环境促进了以LiF/LiN无机组分为主的阴离子衍生SEI的形成，有效抑制了枝晶生长并增强了界面稳定性。优化后的电解质（DMS - 3）展现出卓越的电化学性能：Li||Cu电池在1000次循环（0.5 mA cm）时库仑效率高达99.4%，在800次循环（1.0 mA cm）时为98.8%。Li||LiNiCoMnO全电池在1.0 C下循环500次后容量保持率为89.82%。使用1.2 Ah Li||LiNiCoMnO软包电池的实际验证表明，在110次循环（0.3/0.5 C）后容量保持率为92.
26%。这项工作建立了电解质工程的分子设计范式，为开发高压LMBs提供了关键见解。
