Preparation and interfacial stability of single lithium-ion conductive polymer electrolytes

Three kinds of single lithium-ion conductive polymer electrolytes were synthesized from styrene sulfonyl(trifluoromethosulfonyl)imide lithium (LiSTFSI), polyethylene glycol methyl methacrylate (PEGM), 2,2,3,3-tetrafluoropropyl methacrylate (TFMA) [or 1H,1H,5H-octafluoropentyl methacrylate (OFMA) and dodecafluoroheptyl methacrylate (DFMA)], then made into membranes, and CR 2025 button batteries were assembled accordingly. The membranes obtained were characterized by FTIR, SEM, EIS and linear sweep voltammetry, while the CR 2025 button batteries were evaluated by potentiostatic intermittent titration. The results showed that the synthesized electrolyte membranes exhibited high ionic conductivity (90 ℃, 2.0×10–5 S/cm), wide electrochemical stability window (4.5 V), high lithium-ion transference number (≈1), and high lithium-ion diffusion coefficient (60 ℃, ≥3.7×10–9 cm2/s). The interfacial stability between the electrolyte membrane and lithium metal was significantly improved by heat treatment, which was attributed to the enrichment of fluorine-containing side chain groups on the surface of polymer electrolyte. © 2024 Fine Chemicals. All rights reserved.