Machine-Learning-Guided Screening of Advantageous Solvents for Solid Polymer Electrolytes in Lithium Metal Batteries.

Journal: Nano letters
Published Date: May 14, 2025

Abstract

Trace residual solvents in solid polymer electrolytes (SPEs) significantly affect electrolyte and interface properties, where optimal selection enhances the ionic conductivity and transference numbers. However, the solvent complexity hinders general screening methods. We establish a universal criterion linking electronic (highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO)) and macroscopic properties (dielectric constant, dipole moment, polarizability) via machine learning on an ∼10 000-solvent dataset from high-throughput density functional theory (DFT). Two solvents, -methoxy--methyl-2,2,2-trifluoroacetamide and 2,2,2-trifluoro-,-dimethylacetamide were identified. Experimental incorporation of trace -methoxy--methyl-2,2,2-trifluoroacetamide into a poly(vinylidene fluoride-co-hexafluoropropylene) matrix achieves a 4.5 V window, conductivity of 5.5 × 10 S cm (30 °C), and Li transference number of 0.78. The cell retains 86.7% capacity over 500 cycles (LiFePO) and 98.7% after 200 cycles at 2C (LiNiCoMnO), outperforming 2,2,2-trifluoro-,-dimethylacetamide, dimethylformamide, -methyl-2-pyrrolidone, and dimethyl sulfoxide. This synergy enables balanced ion transport, wide stability, and cycling durability, advancing safer high-energy lithium metal batteries. Our integrated approach establishes a solvent screening paradigm for rational SPE design, accelerating next-generation battery development.

Authors

  • Jiadong Shen
    Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR 999077, China.
  • Junjie Chen
    College of Computer Science and Technology, Taiyuan University of Technology, Taiyuan, China.
  • Xiaosa Xu
    Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR 999077, China.
  • Jin Li
    Mental Health Center, West China Hospital, Sichuan University, Chengdu, China.
  • Zhenyu Wang
    Department of Radiology, Affiliated Hospital 6 of Nantong University, Medical School of Nantong University, Nantong, Jiangsu, China.
  • Pengzhu Lin
    Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR 999077, China.
  • Zixiao Guo
    Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR 999077, China.
  • Yu Wang
    Clinical and Technical Support, Philips Healthcare, Shanghai, China.
  • Jing Sun
    Department of Gastroenterology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
  • Baoling Huang
    Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR 999077, China.
  • Tianshou Zhao
    Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR 999077, China.

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