Mechanical properties and ionic conductivity of gel polymer electrolyte based on poly(vinylidene‐fluoride‐co‐hexafluoropropylene)

Gel polymer electrolytes were prepared from poly(vinylidene‐fluoride‐co‐hexafluoropropylene) (PVH), which had higher mechanical properties and a higher dielectric constant (ϵ = 8–13) than other polymeric matrixes. The mechanical properties and ionic conductivities were investigated as a function of the blend ratio of the electrolyte solution and polymer matrix. Ethylene carbonate/γ‐butyrolactone and lithium triflate were used as the solvent and salt, respectively. The mechanical properties such as the tensile strength, tensile modulus, compression modulus, and dynamic shear modulus were evaluated. The highest ionic conductivity was 1.09 × 10−3 S/cm at 25°C for 40 wt % PVH against the electrolyte solution. The tensile strength, tensile modulus, and compression modulus were increased with increasing PVH content and they all abruptly changed between 70 and 80 wt % PVH. The dynamic shear moduli showed behavior typical of a gel and varied with the shear strain amplitude or applied frequencies.