Porous PVDF mats with significantly enhanced dielectric properties and novel dipole arrangement for high-performance triboelectric nanogenerators

Abstract

In the last decade, various materials and nanoscale modifications have been developed to enhance the performance of the triboelectric nanogenerators (TENGs). Electrospinning of polarizable materials, such as polyvinylidene fluoride (PVDF), has improvements in surface area and dielectric properties through the arrangement of dipoles’ orientation. However, the previously developed electrospun mats for TENG devices still suffer from (i) insufficient dielectric properties due to the presence of low-dielectric air, (ii) process complexity, and (iii) the need for nanoparticle additives. These issues are addressed in this study to develop porous electrospun PVDF mats with significantly enhanced dielectric properties and novel dipole arrangement. Smart multi-layer structures are introduced to overcome the dielectric characteristics of the degraded electrospun mats by the presence of the voids. The new material structure exhibited a significantly increased dielectric constant of 10, which was much higher than single-layer electrospun mats, and was even comparable to the pristine PVDF film without any porosity. Such a material with high dielectric constant and high area-to-volume ratio was utilized as a tribonegative layer in the TENG device, and the corresponding triboelectric performance was analyzed. An output voltage of over 130 V and a current of up to 12 μA were obtained, which were noticeably higher than those of pristine PVDF as well as those of single-layer electrospun mats. Such high performance remained unchanged even after 10,000 cycles. The developed electrospun PVDF mats in this study can therefore be used in the next generation of high-performance TENG devices.