Homogeneous polymer-ionic solvate electrolyte with weak dipole-dipole interaction enabling long cycling pouch lithium metal battery.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40229295.
- Also identified by DOI 10.1038/s41467-025-58689-3 and PMC identifier 11997189.
- Licence recorded as CC BY-NC-ND.
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Abstract
Solid polymer electrolytes (SPEs) are considered as promising electrolytes for high-voltage lithium metal batteries. Whereas, the strong dipole-dipole interaction in polymer electrolytes limits the enhancement of the ionic conductivity. Here, we propose the 1,1,2,2-Tetrafluoroethyl-2,2,3,3-Tetrafluoropropylether (TTE) diluent to significantly regulate the dipole-dipole interaction in polymer-ionic solvate electrolytes (TPISEs). The TTE encapsulates ionic solvate to reduce the dipole-dipole interaction of ionic solvate with the polymer matrix, which promotes their homogeneous distribution, creating a continuous ion percolating network among the polymer matrix. The ion conductivity of TPISEs is therefore enhanced to 1.27×10<sup>-3</sup> S cm<sup>-1</sup> at 25 °C. Meanwhile, the TTE induces the ionic solvate to transform from contact ion pairs to aggregates, contributing to a stable lithium/electrolyte interface with exchange current density 190 times larger than that without TTE. The Li||LiNi<sub>0.8</sub>Co<sub>0.1</sub>Mn<sub>0.1</sub>O<sub>2</sub> full cells exhibit good cycling stability from -30 °C to 60 °C. The practical pouch cells consisting of a thin Li metal foil (50 μm) and a high-areal-capacity positive electrode (3.58 mAh cm<sup>-2</sup>) achieve a high specific energy of 354.4 Wh·kg<sup>-1</sup> and maintain 78.1% capacity after 450 cycles at 54 mA g<sup>-1</sup> and 25 °C. This work provides a design strategy for SPEs beyond the bottleneck of ionic conductivity for practical solid-state batteries.