Decoupled Ion Transport via Triadic Molecular Synergy in Flame‐Retardant Quasi‐Solid Electrolytes for Safe Lithium Metal Batteries

Decoupled Ion Transport via Triadic Molecular Synergy in Flame‐Retardant Quasi‐Solid Electrolytes for Safe Lithium Metal Batteries

Advanced Energy Materials

10.1002/aenm.202501236

https://doi.org/10.1002/aenm.202501236

Kun Li, Anjun Hu, Ruizhe Xu, Wang Xu, Borui Yang, Ting Li, Yuanjian Li, Zhi Wei Seh, Jianping Long, Shimou Chen

16 April 2025

Li, K., Hu, A., Xu, R., Xu, W., Yang, B., Li, T., Li, Y., Seh, Z. W., Long, J., & Chen, S. (2025). Decoupled Ion Transport via Triadic Molecular Synergy in Flame‐Retardant Quasi‐Solid Electrolytes for Safe Lithium Metal Batteries. Advanced Energy Materials, 15(28). Portico. https://doi.org/10.1002/aenm.202501236

AbstractIonic liquids (IL)‐based quasi‐solid polymer electrolytes (QSPEs) hold promise for safe lithium metal batteries owing to their tunable electrochemical properties and processability. However, traditional design strategy has ignored the interdependencies among “component‐function‐interface”, leading to compromised practical applications hindered by sluggish lithium‐ion transport kinetics and safety concerns. Herein, a triadic molecular synergy paradigm is proposed to decouple lithium‐ion conduction mechanisms in flame‐retardant QSPEs. Pentaerythritol tetraacrylate‐lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) provides the structural framework, while the IL (1‐butyl‐3‐methylimidazole bis (trifluoromethylsulfonyl) imide, BmimTFSI) as a plasticizer softens the polymer chains by weakening the intermolecular forces to provide an additional ion‐transport pathway while imparting flame‐retardant properties. Additionally, the highly electronegative fluorine atoms of the additive (2‐(perfluorohexyl)ethyl methacrylate, PFMA) promote LiTFSI dissociation through electron cloud migration, simultaneously immobilizing TFSI⁻ anions and suppressing cationic competition through strong PFMA−Bmim+ coordination. As a proof‐of‐concept, this synergistic design achieves a high lithium‐ion transference number (0.72), forms a stable lithium fluoride‐dominated interphases, and enhances battery safety via a condensed‐phase flame‐retardant mechanism. Experimental validation demonstrates that the designed quasi‐solid electrolyte significantly enhances cycling stability in Li symmetric cells, Li||LiFePO4 and Li||LiNi0.8Co0.1Mn0.1O2 cells. The proposed molecular engineering strategy establishes a paradigm for developing high‐performance QSPEs in lithium metal batteries.

Publisher Copyright

This research / project is supported by the Singapore National Research Foundation - NRF Investigatorship NRF-NRFI09-0002
Grant Reference no. : NRF-NRFI09-0002

This research / project is supported by the the Agency for Science, Technology and Research - Manufacturing, Trade, and Connectivity Programmatic Fund M23L9b0052
Grant Reference no. : M23L9b0052

This is the peer reviewed version of the following article: Li, K., Hu, A., Xu, R., Xu, W., Yang, B., Li, T., Li, Y., Seh, Z. W., Long, J., & Chen, S. (2025). Decoupled Ion Transport via Triadic Molecular Synergy in Flame‐Retardant Quasi‐Solid Electrolytes for Safe Lithium Metal Batteries. Advanced Energy Materials, 15(28). Portico. https://doi.org/10.1002/aenm.202501236 , which has been published in final form at https://doi.org/10.1002/aenm.202501236. Digital Object Identifier (DOI). This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.

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