Synergistic effects of salt concentration and polymer blend composition on the crystal phases, dielectric relaxation, and ion conduction in PVDF/PEO/LiCF3SO3 solid polymer electrolytes

Dielectric polarization and relaxation processes of the lithium-ion conducting PEO/PVDF blend matrix-based electrolytes: effect of TiO2 nanofiller

“…Each arc represents the equivalent parallel combination circuit of an energy storing element C p and a dissipating element R p . The shapes of these impedance plots are found in good resemblance with that of the several similar types of electrolyte [14,26,30,32,35,43,69]. Further, the shape of the Nyquist plot of NSPE20 film indicates that the arc and spike parts in the plot are not clearly separable as usually noted for the other electrolytes which reflect that there may be few stiffer domains on the film surfaces resulting in poor electrode/electrolyte contact [70].…”

“…8 Degree of crystallinity X c (%) (X c(p) and X c(t) ), chain segmental relaxation time τ s , and dc ionic conductivity σ dc (σ dc(σ′) and σ dc(Rb) ) versus x (wt%) plots of (75PEO/25PVDF)/2 wt% LiClO 4 -x wt% TiO 2 films (x = 0, 2, 5, 10, 15, and 20), at 27 °C from zero to about 3 V confirming the stability of the materials up to 3 V, and after that, it increases rapidly indicating that some decomposition of the electrolytes have started on the blocking electrodes. The threshold voltage at which decomposition of the material starts is termed as stability voltage (V s ), and for all the studied NSPE films its value is found ≥ 3 V which is a considerable value confirming them as potential candidates for the high voltage LIBs [8,10,19,35,69,70]. The CV traces of the NSPE films are presented in Fig.…”

“…Recently, we investigated detailed structural and dielectric properties of the PEO/PVDF blends over the entire blend composition range [42], these polymers blends based nanocomposites [68], and also a variety of SPE materials [35,69,70]. In continuation of these researches on the PEO/PVDF blend matrix-based various types of flexible dielectric and electrolyte materials, the present manuscript deals with the NSPE materials comprising (75PEO/25PVDF)/25 wt% LiClO 4 -x wt% TiO 2 compositions.…”

“…Among these approaches, the blending of polymers and their use as host matrices for the preparation of appropriate properties SPEs is a valid and more feasible green chemistry process that has been exemplified by various research groups [10, 17-21, 26, 29, 32]. The blending process not only suppresses the unwanted properties of individual polymers but also enhances the required superior properties that can be engineered through an appropriate compositional weight ratio of the blended polymers [14,17,18,35,36]. The addition of nano-sized fillers in the host polymer matrix is also a widely popular and efficient strategy to get improved physicochemical properties of the prepared NSPE materials [6,10,18,22,30,37].…”

Free-standing Li+-conductive films based on PEO–PVDF blends

“…29 Although dry polymer blends were mainly studied with PVC, PVDF might be preferable for battery application due to its higher chemical stability and such blends were also reported as SPEs with LiClO 4 or LiCF 3 SO 3 salts. 30,31 Herein, we focus on optimization of Li-conducting SPE obtained by blending PEO and PVDF with LiTFSI. Using FTIR spectroscopy, XRD and DSC and additional DFT modelling we uncover the reasons of enhancement of the mechanical properties and ionic conductivity achieved for optimized material composition.…”