Enhanced dielectric properties of PFBA@rGO/PVDF-HFP flexible films by non-covalent modification for energy harvesting applications

Abstract

Dielectric modulation of triboelectric materials has proven to be a viable approach for enhancing triboelectric nanogenerator (TENG) performance. Nevertheless, the construction of high dielectric composites with optimal interfacial compatibility and exceptional performance is a matter of immediate concern. Graphene oxide (rGO) was modified with pentafluorobenzoic acid (PFBA) to synthesize PFBA@rGO/PVDF-HFP composite films via the casting method. A mass fraction of 5 wt% PFBA@rGO results in a dielectric constant of 211 at a frequency of 40 Hz, which is 15 times greater than that of the pure PVDF-HFP film. Furthermore, the dielectric loss remains low at 0.7. The modification created a stable molecular interface between PVDF-HFP and rGO, improving the compatibility between the rGO filler and PVDF-HFP matrix. This interfacial polarization significantly boosted the composites’ dielectric constant, enabling PFBA@rGO in PVDF-HFP to react flexibly to external electric fields. The TENG with 5 wt% PFBA@rGO/PVDF-HFP achieves a maximum open-circuit voltage of 70 V, which is double that observed for pure PVDF-HFP. This enhancement results from the material’s high dielectric properties, which increase surface charge density. The TENG can light 69 LED bulbs and charge a 3.3 μF capacitor to 5 V in less than a minute. This study provides new insights into the unique potential of the dielectric-modulated output enhancement strategy for TENG in energy harvesting.