Preparation and application of solid polymer electrolyte based on deep eutectic solvent

Deep eutectic solvent (DES) was prepared from choline chloride/1,3-butanediol (CHCl/BG). DES, 1-methyl-2-pyrrolidone (NMP) and poly-vinylidene fluoride (PVDF) was cross-linked and mixed to prepare a solid polymer electrolyte (SPE). The SPE was characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The goal was to identify major functional group and element composition. Results showed that SPE contained the C-N, C-O, C-H, C-Cl, C-F, N-C=O functional groups and oxygen atom, nitrogen atom, carbon atom, chlorine atom, fluorine atom. The DES was characterized by Transmission electron microscopy (TEM). The goal was to identify microscopic morphology. Results showed that DES is dominated by amorphous. The SPE was characterized by Scanning electron microscopy (SEM). The goal was to identify pore structure. Results showed that pore structure is dominated by amorphous. The SPE was characterized by X-ray diffraction (XRD) and Differential scanning calorimetry (DSC). The goal was to analyze the crystallinity of SPE. Results showed that heat treatment temperature and time increase resulted in a significant increase in crystallinity. Cyclic voltammetric measurements (CV) showed that the SPE has relatively good stability. The results demonstrated that when the weight ratio of CHCl: BG was 1:1, the conductivity of DES is best. Studies had shown that when the weight ratio of DES: PVDF: NMP was 1:1:4, the conductivity of SPE is best. Studies had shown that it optimum treatment temperature for SPE was 90°C for 6 minutes. The SPE had been applied to NO₂ gas sensor.