Elucidating the relationship between mechanical properties and ionic conductivity in a highly conductive gel polymer electrolyte

The storage modulus and ionic conductivity of prototypical gel electrolytes consisting of different amounts of poly (vinyl alcohol) and the ionic liquid 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (EMI TFSI) were made and characterized. Peak ionic conductivity and room temperature storage modulus of 2.4 × 10−2 S cm−1 and 128 MPa respectively were achieved. The gel electrolytes were also characterized with a multifunctional index. It was found that the optimal ionic conductivity and mechanical properties were obtained with 40 wt% EMI TFSI loading, where an ionic conductivity of 1.2 × 10−3 S cm−1 and a room temperature storage modulus of 30.7 MPa were obtained. A specific capacitance of 29.24 F g−1 was obtained in a test supercapacitor device.