Enhancing the output performance of fluid-based triboelectric nanogenerator by using poly(vinylidene fluoride-co-hexafluoropropylene)/ionic liquid nanoporous membrane

Abstract

Over the past few years, triboelectric nanogenerators (TENGs) have emerged as promising devices for energy harvesting and self-powered sensing owing to their miniaturized structural design, lack of material limitation, high stability, and ecofriendly nature. In this study, the membrane consisting of poly(vinylidene fluorideco-hexafluoropropylene) (PVDF-HFP) and ionic liquid (PIL) is fabricated as triboelectric material, namely PIL membrane. To further improve the hydrophobicity of the membrane and the output performance of the TENG, different PIL membranes are prepared using various IL concentrations and their structures are modified using the evaporation phase inversion technique. The PIL membranes with nanoporous structures and strong hydrophobicity are synthesized by blade coating and bent to generate circular tube shapes for use in PIL-TENG cells. Therefore, the PIL-TENG has a high output performance owing to the availability of more ions through the establishment of an electrical double layer and an increase in electronegativity properties by doping with more fluoride atoms. Under optimal conditions, a nanoporous PIL-TENG of 10 wt.% ionic liquid exhibited the maximum peak-to-peak with an output voltage of 16.95 V and current of 2.56 μA. Especially, the instantaneous peak power density of the PIL-TENG reached the highest value of 26.1 mW/m2, which was 212% higher than that of the pristine PVDF-HFP TENG (P-TENG). In this manner, a new material for the triboelectric layer is presented to effectively improve the output performance, stability, and durability of TENGs, which are promising for use in practical applications related to harvesting hydrokinetic energy, self-powered sensors, and other applications