Development of solid polymer electrolytes based on poly(vinylidene fluoride-trifluoroethylene) and the [N1 1 1 2(OH)][NTf2] ionic liquid for energy storage applications

• New SPE of P(VDF-TrFE)/[N1 1 1 2(OH)][NTf2] was prepared for energy storage applications.
• The morphology and degree of crystallinity of the SPE depend on IL content.
• An ionic conductivity at RT of 1.7 × 10− 5 S·cm− 1 is found for 32 wt.% IL content.
• The equivalent circuit for these SPEs is presented.
• The SPE membranes have adequate electrochemical properties for energy storage applications.

P(VDF-TrFE), solid polymer electrolytes were prepared using the ionic liquid N,N,N-trimethyl-N-(2-hydroxyethyl)ammonium bis(trifluoromethylsulfonyl)imide, [N1 1 1 2(OH)][NTf2].The morphology, polymer phase, and thermal and electrochemical properties have been determined by scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), differential scanning calorimetry (DSC) and impedance spectroscopy, respectively. The addition of the ILs in P(VDF-TrFE) affects the microstructure, thermal stability and ionic conductivity of the polymer membrane.It was found that the ionic conductivity increases as the ionic liquid (IL) content increases with a maximum value at room temperature of 1.7 × 10− 5 S·cm− 1 for an IL composition of 32 wt.%. The temperature behavior in the ionic conductivity is thermally activated, following the Arrhenius equation, the high ionic conductivity resulting from the large carrier numbers of the IL.The electrochemical potential window shows 1.0 V at 4.0 V that these solid polymer electrolytes are adequate for energy storage devices.