Wang Jianing, Liang Xueying, Mao Zhifei, Shi Xiaojun, Zhang Taoqiu, Cao Minglei, Jin Jun, Wang Rui, Gong Yansheng, Shen Xiang, Wang Huanwen
Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074, China.
Shenzhen Research Institute of China University of Geosciences, Shenzhen 518057, P. R. China.
J Phys Chem Lett. 2025 Sep 18;16(37):9739-9747. doi: 10.1021/acs.jpclett.5c02504. Epub 2025 Sep 9.
Ether-based electrolytes are widely acknowledged for their potential to form stable solid electrolyte interfaces (SEIs) for stable anode performance. However, conventional ether-based electrolytes have shown a tendency for cation-solvent co-intercalation phenomena on graphite electrodes, resulting in lower capacity and higher voltage platforms compared to those of neat cation insertion in ester-based electrolytes. In response, we propose the development of weakly solvating ether solvents to weaken the interaction between cations and solvents, thereby suppressing co-intercalation behavior. In this study, theoretical calculations first demonstrate that tetrahydrofuran (THF) exhibits a smaller binding energy (-0.89 eV) with K in comparison to 1,2-dimethoxyethane (DME, -1.37 eV) and ethylene carbonate (EC, -1.26 eV). Consequently, solvent co-intercalation, electrolyte decomposition, and graphite exfoliation are suppressed in a 1 M solution of K salt in THF. Simultaneously, a uniform and robust SEI is formed to improve the K storage stability of the graphite anode (99% capacity retention after 200 cycles at 0.1 A g). Meanwhile, such a THF-based K-ion electrolyte also exhibits good adaptability when applied to both hard and soft carbonaceous anodes. This work addresses the challenges associated with achieving high capacity and stable graphite anodes in ether-based electrolytes, offering a solution to the problem of cation-solvent co-intercalation. The findings also promote the application of graphite anodes in potassium-ion batteries, emphasizing the significance of weakly solvating ether electrolytes in enhancing battery performance and stability.
基于醚的电解质因其形成稳定固体电解质界面（SEI）以实现稳定阳极性能的潜力而被广泛认可。然而，传统的基于醚的电解质在石墨电极上表现出阳离子 - 溶剂共嵌入现象的趋势，与酯基电解质中纯阳离子嵌入相比，导致容量较低和电压平台较高。作为回应，我们提出开发弱溶剂化醚溶剂以减弱阳离子与溶剂之间的相互作用，从而抑制共嵌入行为。在本研究中，理论计算首先表明，与1,2 - 二甲氧基乙烷（DME，-1.37 eV）和碳酸亚乙酯（EC，-1.26 eV）相比，四氢呋喃（THF）与K的结合能较小（-0.89 eV）。因此，在THF中的1 M K盐溶液中，溶剂共嵌入、电解质分解和石墨剥落受到抑制。同时，形成均匀且坚固的SEI以提高石墨阳极的K存储稳定性（在0.1 A g下循环200次后容量保持率为99%）。此外，这种基于THF的K离子电解质在应用于硬碳和软碳阳极时也表现出良好的适应性。这项工作解决了基于醚的电解质中实现高容量和稳定石墨阳极所面临的挑战，为阳离子 - 溶剂共嵌入问题提供了解决方案。这些发现还促进了石墨阳极在钾离子电池中的应用，强调了弱溶剂化醚电解质在提高电池性能和稳定性方面的重要性。
