Ion Conduction, Dielectric and Mechanical Properties of Epoxy-Based Solid Polymer Electrolytes Containing Succinonitrile

초록

We use impedance spectroscopy to investigate ionic conduction and dielectric response and mechanical tests to study mechanical properties of cross-linked epoxy-based solid polymer electrolytes (SPEs) containing a mixture of succinonitrile (SN) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) with different ratio of mechanically robust epoxy and ionic conducting SN/LiTFSI mixture content. Increasing SN/LiTFSI mixture content results in a proportional increase in ionic conductivity sigma (DC) , and its maximum conductivity approaches sigma (DC) 10(-4) S/cm at room temperature. This is consistent with accelerating the observed relaxation processes such as ion rearrangement and segmental motion, upon adding further SN/LiTFSI content. The combination of epoxy and SN/LiTFSI also leads to a large increase in static dielectric constant epsilon (s) 75, which is higher than the prediction from the Landau and Lifshitz mixing rule, compared to the host epoxy (epsilon (s) 4) and pure SN/LiTFSI mixture (epsilon (s) 53). On the other hand, the addition of SN/LiTFSI decreases Young's modulus (E), compared to the neat epoxy, and approaches E10 MPa at room temperature, reflecting a trade-off relationship between E and sigma (DC) .

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