Professor Xu Youlong's research team from the Advanced Energy Storage Electronic Materials and Devices Institute at Xi'an Jiaotong University (XJTU) has proposed an innovative "molecular synergy engineering" strategy and developed a fluoride-amide-based deep eutectic gel polymer electrolyte (PDEE−UBP) with high safety, fast ion transport, and a wide voltage stability window.

By performing in-situ polymerization on a fluorine-containing deep eutectic system, the electrolyte obtained excellent intrinsic flame retardancy and interfacial compatibility, reducing safety risks.

To address the shortcomings of gel polymer electrolytes in interfacial stability and high-voltage adaptability, a ternary synergistic additive strategy was adopted. This regulates intermolecular synergy, enabling precise coupling at the molecular level between interfacial chemistry control, solvation structure optimization, and macroscopic electrochemical performance.

This strategy forms a chemically stable, inorganic-rich solid electrolyte interphase structure, achieving a unification of high-voltage compatibility and long-term cycle stability and providing a new design paradigm and theoretical basis for developing high-safety, high-energy-density next-generation lithium metal battery electrolyte systems.

Experimental results show that the PDEE−UBP electrolyte exhibits excellent comprehensive performance: an ionic conductivity of 2.83 mS cm−1 (25 C), an electrochemical window of 5.6 V (meeting the needs of all high-voltage cathodes), and a lithium-ion transference number as high as 0.68.

A 4.5 V lithium cobalt oxide battery using this electrolyte has a capacity retention rate of 92.3 percent after 1,000 cycles at 3 C rate, demonstrating excellent fast-charging performance and cycle stability.

These research findings, titled Molecular Synergy Engineering of Fluorinated Eutectic-Based Polymer Electrolytes for Fast-Charging and High-Voltage Lithium Metal Batteries, were recently published in the prestigious international energy materials journal Advanced Functional Materials.