The Preparation, Performance And Application Of Triboelectrical Nanogenerators Based On Dielectric Materials

As an energy harvester and a self-powered sensor,the triboelectric nanogenerator?TENG?possesses great application prospect and research value due to its excellent flexibility,lightweight,wearability,implantability,wide energy harvesting scale,high energy conversion efficiency,fast response speed,and low manufacturing cost.The friction layer is an important part of the TENG.The friction layer based on dielectric material exerts an important influence on improving the output performance and sensing characteristics of the TENG.Therefore,it is of vital importance for the development of the TENG to construct the morphologies,optimize the structures,and adjust the composition of dielectric materials.In this thesis,a heart-like micro-nanofiber based wearable triboelectric nanogenerator?HMN-TENG?with high performances is demonstrated.The three-dimensional?3D?secondary heart-like structure is designed and self-assembled on an electrospun poly?vinylidene fluoride??PVDF?fiber based tribonegative layer,and this structure can match the depressed structures on the tribopositive layer.Therefore,the HMN-TENG delivers the power density of up to 14.8 W/m²by the“occlusion effect”.A bio-inspired Trimurti PVDF tribo-material with a transcendent electrical performance,excellent output stability in high environmental humidity,and increased use of comfort under a sweating condition is designed,by simple self-assembly of electro-pore-creating.The nanoporous cancellous-bone-like,hydrophobic lotus-leaf-like,and hydrophilic root-xylem-like structures are assembled respectively in the interior,on the upper surface and on the bottom surface of Trimurti PVDF mat,endowing the fabricated Trimurti triboelectric nanogenerator?T-TENG?with outstanding electrical performances and availability in different application environments.A bio-inspired petiole-like micron fiber-based tribo-material with inner nanopores,rough surface nanostructures and superhydrophobicity is designed that uses an extraordinarily simple,ultralow-waste and efficient single-component electrospinning process.The petiole-like structures and superhydrophobicity endow the assembled triboelectric nanogenerator?PMF-TENG?with outstanding electrical performance of56.9 W/m²and superior output stability of 22%under a high relative humidity of 80%.Achieving high electrical outputs in a TENG based on an organic-inorganic composite inner-layer is proposed by electrostatic atomization with hot pressing treatment.The inner-layer consisting of polyimide?PI?and 0.85Na_0.5Bi_0.5TiO₃-0.15SrTiO₃?NBT-15ST?ceramic particles?CPs?can distinctly enhance the output voltage of the device to 118.1 V by coupling charge storage effect and hysteretic dielectric polarization.The TENG with flexible inorganic Pb_0.94La_0.04(Zr_0.98Ti_0.02)O₃?PLZT 4/98/2?antiferroelectric thin film as interlayer is prepared by sol-gel method.According to the working cycle mode of TENGs,a new mechanism of improving the electrical performances of the device with a large polarization differential interlayer is studied.The antiferroelectric material has a large saturation polarization under an electric field.When the electric field is removed,its residual polarization is close to zero.Consequently,this kind of material can not only improve the surface charge density,but also avoid part of the charge being bound to the electrode all the time,and fully release the energy harvesting ability of the dielectric material of the TENG.