Single-ionic gel polymer electrolyte based on polyvinylidene fluoride and fluorine-containing ionomer

The novel single-ionic conductive gel polymer electrolyte was prepared from polyvinylidene fluoride (PVDF), propylene glycol carbonate (PC) and a new fluorine-containing ionomer. Cation–carbonyl interaction behavior, morphology and ionic conductive properties of this gel polymer electrolyte were studied by infrared spectra analysis (IR), nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and complex impedance analysis. The results showed that the fluorine-containing ionomer was miscible with both PVDF and PC, and that the carbonyl groups in the ionomer and PC could bond competitively with the cation. Both the content of fluorine-containing ionomer and the content of PC had a great effect on morphology and ionic conductive properties of the samples. For this new gel polymer electrolyte, an ionic conductivity of above 10−4 S cm−1 at room temperature could be reached, and this electrolyte system was a single-ionic kind gel polymer electrolyte with the transport number of the sodium ion exceed 0.99 (t+>0.99).