Fig. 6. SEM images of: (a) pristine LiTFSI salt, (b) polymer-in-salt electrolyte comprising poly(AN-co-BuA) and 91 wt.% of LiTFSI, aged 595 days.TEM images and ARRY-142886 diffraction patterns of polymer-in-salt electrolytes comprising poly(AN-co-BuA) and: (c-d) 84 wt.% of LiTFSI, sample aged 183 days, amorphous structure, (e-f) 91 wt.% of LiTFSI, sample aged 145 days, crystalline structure.Figure optionsDownload full-size imageDownload as PowerPoint slide
Fig. 7. X-ray diffraction patterns of pure LiN(CF3SO2)2 salt and films of poly(AN-co-BuA) with LiTFSI with high salt content up to 95 wt %. Tick marks above the 2θ axis indicate allowed Bragg reflections from crystalline LiN(CF3SO2)2 according to . Reflections marked A and S originate from aluminum foil cover and steel support of the sample, respectively.Figure optionsDownload full-size imageDownload as PowerPoint slide
3.4. Raman scattering spectra
The results of Raman and IR spectroscopy for pristine LiTFSI are thoroughly documented , ,  and . For presently studied system, the interaction of the salt with polymer polar groups such as CN is considerably weaker than that in polyethers and depends on the anion and on the salt concentration. The formation of complexes of polymer and salt result in an increase of the vibration frequency of the CN bond observed in Raman spectra  and . As a result of complexation, a new band at about 2270 cm−1 attributed to the groups engaged in complexes with positive salt ions appears, in addition to the band of the free CN group at 2244 cm−1.