Chen, K., Hu, A., Yang, W., Li, Y., Seh, Z. W., Li, F., Long, J., & Chen, S. (2025). Symmetrical Molecular Topology Enables Ultrathin Solid Polymer Electrolytes for Stable Lithium‐Metal Batteries. Advanced Functional Materials, 36(3). Portico. https://doi.org/10.1002/adfm.202513143
Abstract:
Solid polymer electrolytes (SPEs) have emerged as promising candidates for lithium-metal batteries owing to their advantages in safety, flexibility, and processability. However, ultrathin SPEs (<10 µm) still face challenges in practical applications, including structural inhomogeneity, sluggish ion transport, and lithium dendrite penetration. This study breaks through the conventional paradigm of compositional modulation and proposes a symmetrical molecular topology design strategy based on 2,2-Bis(4-allyloxy-3,5-dibromophenyl)propane (BADBP) polymerization network. The diallyloxy symmetric structure of BADBP bridges and constructs a 3D crosslinked network, effectively repairing the pore defects in the poly(vinylidene fluoride-co-hexafluoropropylene) matrix, achieving an ultrathin thickness of 6 µm with high mechanical robustness and uniform ion channels. The bromophenyl groups in BADBP reduce the crystallinity of the matrix via steric hindrance effects, while the high bond energy of C─Br bonds endows the electrolyte with exceptional thermal stability. Moreover, bromine atoms electrostatically anchor TFSI⁻ anions, promoting lithium salt dissociation and forming a LiF/LiBr-rich interphase layer. As a result, the modified Li||LiNi0.8Co0.1Mn0.1O2 cells demonstrate stable cycling at both room temperature and 60 °C, along with 5C fast-charging capability. The pouch cell further passes nail penetration and high-temperature safety tests. This work establishes a design paradigm for designing high-performance ultrathin SPEs in lithium-metal batteries.
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Funding Info:
This research / project is supported by the Singapore National Research Foundation - NRF Investigatorship
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
Grant Reference no. : M23L9b0052
Description:
This is the peer reviewed version of the following article: Chen, K., Hu, A., Yang, W., Li, Y., Seh, Z. W., Li, F., Long, J., & Chen, S. (2025). Symmetrical Molecular Topology Enables Ultrathin Solid Polymer Electrolytes for Stable Lithium‐Metal Batteries. Advanced Functional Materials, 36(3). Portico. https://doi.org/10.1002/adfm.202513143
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