The solvent casting method was used for five types of polyvinylidene difluoride (PVDF) nanocomposite film preparation. The effect of nanofillers in PVDF nanocomposite films on the structural, phase, and friction and mechanical properties was examined and compared with that of the natural PVDF film. The surface topography of PVDF nanocomposite films was investigated using a scanning electron microscope (SEM) and correlative imaging (CPEM, combinate AFM and SEM). A selection of 2D CPEM images was used for a detailed study of the spherulitic morphologies (grains size around 6–10 μm) and surface roughness (value of 50–68 nm). The chemical interactions were evaluated by Fourier transform infrared spectroscopy (FTIR). Dominant polar γ-phase in the original PVDF, PVDF_ZnO and PVDF_ZnO/V, the most stable non-polar α-phase in the PVDF_V_CH nanocomposite film and mixture of γ and α phases in the PVDF_V and PVDF_ZnO/V_CH nanocomposite films were confirmed. Moderately hydrophilic PVDF nanocomposite films with water contact angle values (WCA) in the range of 58°–69° showed surface stability with respect to the Zeta potential values. The effect of positive or negative Zeta-potential values of nanofillers (ζ_n) on the resulting negative Zeta-potential values (ζ) of PVDF nanocomposite films was demonstrated. Interaction of PVDF chains with hydroxy groups of vermiculite and amino and imino groups of CH caused transformation of γ-phase to α. The friction properties were evaluated based on the wear testing and mechanical properties were evaluated from the tensile tests based on Young’s modulus (E) and tensile strength (Rm) values. Used nanofillers caused decreasing of friction and mechanical properties of PVDF nanocomposite material films.

Polyvinylidene fluoride (PVDF) is one of the materials most commonly used in membrane separators. The structures of pristine PVDF and PVDF nanocomposite films were processed via hot pressing at 140 °C, 170 °C, and 185 °C at a pressure of 2 tons for 15 min. According to a surface investigation using scanning electron microscopy (SEM), the spherulitic character of the PVDF nanocomposite films was preserved up to a pressing temperatures of 140 °C. The cross-sectional SEM images confirmed that higher pressing temperatures (170 °C) caused the structures to be compacted into monolithic films, and a pressing temperature of 185 °C caused the melting of the PVDF matrix and its recrystallization into thin films (21–29 μm). An average crystallinity value of 51.5% was calculated using differential scanning calorimetry (DSC), and this decreased as the pressing temperature increased. Fourier transform infrared (FTIR) measurements confirmed the presence of a dominant γ phases in the PVDF nanocomposite films, whose nanofillers consisted of vermiculite particles (ZnO_V and ZnO_V_CH) and mixed α + γ phases. The percentage of the electroactive γ phase (approximately 79%) was calculated via a FTIR analysis, and the ratio between the β phase and the α phase was determined from the Raman spectra. A hydrophilic surface with contact angles ranging from 61 to 84° was demonstrated for all the PVDF nanocomposite membranes. The superoleophilic surface was measured using poly(dimethylsiloxane) with contact angles ranging from 4 to 13°, and these angles reached lower values when in contact with sulfur particles.

The battery production reached 1,490 GWh in 2024, with Li-ion batteries comprising 80%. This growing demanded to a tightening of conditions regarding enhanced battery safety and environmental impact. A key component influencing safety is the separator, which electrically insulates the electrodes while enabling the transport of lithium ions. Polyvinylidene fluoride (PVDF) and its copolymer with chlorotrifluoroethylene (PVDF-CTFE) are promising alternatives to commercial separators. Their properties can be further improved using nanofillers to enhance mechanical strength, thermal resistance, electrochemical stability and ionic conductivity. This review emphasises that the selection of nanofillers can positively impact the safety-related properties of PVDF and contributes to the development of more efficient and durable energy storage solutions.