Modified Thermal, Dielectric, and Electrical Conductivity of PVDF-HFP/LiClO₄Polymer Electrolyte Films by 8 MeV Electron Beam Irradiation

Abstract

The polymer electrolyte films (poly((vinylidene fluoride)- co -hexafluoropropylene)/LiClO 4 @90:10 w/w, PHL10) were prepared by solution-casting technique and the effect of various dosages of electron beam (EB) irradiation on structure, morphology, thermal, dielectric, and conductivity properties at various dosages. The atomic force microscope topography image shows substantial change in surface morphology due to irradiation and the modification of chemical bonds through chain scission process with increased EB dose was confirmed by Fourier transform infrared spectroscopy studies. NMR studies confirm the change in structural properties due to irradiation. The X-ray diffractometer confirms the decreased crystallinity from 50.10 for unirradiated film to 40.96 at 120 kGy doses; hence, increase in amorphousity due to a decrease in melting temperature from 460 to 418 °C leads to the degradation of the polymer, and the differential scanning calorimetry study reveals the decreased crystallinity with increased irradiation dose. The dielectric and modulus parameters are observed to decrease with increasing frequency as well as temperature. The conductivity increases with frequency and EB dose due to the increased segmental motion of charged ions by chain scission/cross-linking process. The high conductivity of 1.81 × 10 –3 S/cm with the corresponding relaxation time of 1.697 × 10 –6 at 120 kGy dose was observed. The conduction mechanism reveals an Ohmic behavior and the I – V plot exhibits a gradual increase in current with applied voltage as well as irradiation dose. The electrochemical performance of the irradiated polymer electrolyte was improved significantly and hence the polymer electrolytes can be used in solid-state batteries and storage applications after altering the properties by the influence of irradiation.

The effect of temperature on the electrical and thermal conductivity of graphene‐based polymer composite films

“…Gn, graphene; PC, polymer composites; PVDF-HFP, poly(vinylidene fluoride-cohexafluoropropylene); SEM, scanning electron microscope phase of the PVDF-HFP copolymer. 34,36 This result agrees with the melting temperature value that was found by thermal gravimetric analysis (TGA) that was done by the authors in a previous publication. 18 The thermal stability of polymer composites is an important parameter that can be obtained from the TGA analysis.…”

Enhancement of Electrochemical Stability Window and Electrical Properties of CNT-Based PVA–PEG Polymer Blend Composites

“…The electric module behavior has been studied by using the formula { .25ex2ex lefttrue M * = M ′ + i M ″ M ″ = ε ′ false( ε ′ false) 2 + false( ε ″ false) 2 = ω C normalo Z ″ M ″ = ε ″ false( ε ′ false) 2 + false( ε ″ false) 2 = ω C normalo Z ′ where M ′ and M ′′ are the real and imaginary parts of electric modulus, ω is the angular frequency, C o is the capacitance of the dielectric material and Z ′ and Z ′′ are the real and imaginary parts of the impedance . Since both the value M′ (see Figure i) and M″ (see inset of Figure ii) are very close to zero at the lower frequency side which shows the migration of ions in polymer/polymer-blend and M′ (i.e., = ωC o Z ′′) and M″ (i.e., = ωC o ZωC o Z ′ ), both shifts toward higher frequency side with increasing temperature (i.e., the motion of ions became faster and hence charge carriers are thermally activated) and MWCNTs fillers, although, the values of M′ and M″ both are very close to zero at lower frequency and increase at higher frequency.…”

Electron-Beam Irradiation for Boosting Storage Energy Density of Tuned Poly(vinylidene fluoride-hexafluoropropylene)/Graphene Nanoplatelet Polymer Composites

“…It might occur because it approaches or is closely the same with the resonance frequency of the charge carriers in the polymer chain. This frequency dependence of AC conductivity could be related to the activated trapped charges release [47]. The increased AC conductivity in the HFP/GN composites may have been caused by their dipole density and GNPs themselves that are highly conductive.…”