Synergistic Modulation of Structural and Surface Features of PVDF Using CoAlLDH Nanofillers for Triboelectric Nanogenerator Applications

PVDF-based TENGs can achieve enhanced performance through strategic modifications of their bulk and surface properties. Compositing PVDF with different fillers and examining their effects on its triboelectric properties in the context of TENG remains an open area for investigation. In this study, Cobalt Aluminum Layered Double Hydroxide (CoAlLDH) was incorporated into PVDF to investigate its effect on the triboelectric performance of PVDF through synergistic modification of its structural and surface features. The filler concentration optimization of the PVDF–CoAlLDH (PVLD) composite was carried out and correlated with the electroactive (EA) phase modulations, changes in surface features, and dielectric properties of the composites. An increase in the surface coverage of PVDF films via a progressive transition from the bead-like morphology of pristine PVDF to a more continuous surface morphology in the composites was observed by SEM analysis. Moreover, an enhancement in the EA phase content of PVDF was also observed with the incorporation of CoAlLDH by evaluation of the XRD and FTIR of the composites. EIS studies of the films showed an increase in the dielectric constant of PVDF from ∼4 to a maximum of ∼21 with an increase in CoAlLDH loading, indicating that PVLD films retain more surface charges compared to PVDF. The effect of incorporating CoAlLDH through synergistic modification of surface and structural properties of PVDF on their triboelectric output was analyzed. The maximum peak-to-peak voltage of pristine PVDF (∼50 V) increased significantly to ∼330 V for PVDF loaded with 20% CoAlLDH (PVLD-20%). Similarly, the current output increased from ∼4.1 μA for pristine PVDF to ∼10.6 μA for PVLD-20%. These measurements were obtained under a contact–separation force of 10 N and a frequency of 10 Hz, using Nylon-6 as the tribopositive layer. Resistive impedance matching of the PVLD 20% shows that the maximum power attained for pristine PVDF film was ∼0.4 mW, and it increased up to ∼5.12 mW at an equivalent external load. Moreover, the practicality of the TENG was demonstrated by glowing 56 LEDs connected in series by foot-tapping the TENG.