Investigation Of Energy And Sensing Application Based On Triboelectric Nanogenerator

Wireless sensor network as the most basic unit of the perception layer in Ineternet of Things(Io Ts),which has wide applications in intelligent manufacturing.However,the sensor technology of China is highly dependent on imports,seriously restricting the development of Io Ts industry.Therefore,exploring new sensor technology is one of the important issues that needs to be addressed.On the other hand,utilizing the traditional battery and cable power supply to drive the whole sensor networks,not only need a high maintenance cost,but also lead to serious environmental pollution problems,which can't satisfy the energy demand of the current sensing network.Based on the new energy technology harvesting mechanical energy from the environment to realize self-powered electronics or systems has become an inevitable direction for the future development of Io T sensors.In 2012,Pro.Zhonglin Wang invented the first triboelectric nanogenerator(TENG)device based on the triboelectrification and electrostatic induction.From the perspective of mechanics,TENG opens up a brand new field of low-frequency energy acquisition and sensing,which bounds to promote the industrialization of self-powered sensor networks.At present,technical issues of TENG,utilization of the output characteristics and exploring its applications are the research focuses to expand its practicability.In this paper,enhancement of TENG's output performance and stability,harvesting of hybrid energy,design and application of sensors are discussed as follows:(1)Device physics:to solve the small surface charge density of TENG,the strategy that modifies the dielectric coefficient and porosity of material is proposed based on the capacitance model.The effects of doping highly dielectric nanoparticles into polydimethylsiloxane(PDMS)and constructing porous sponge structures on output performance of TENG were verified by theoretical calculation and experimental tests.The output performance of TENG can be optimized by filling nanoparticles and porosity.At 10%Strontium Titanate and 15%porosity,the maximum open-circuit voltage,short-circuit current,and power density increase to 338 V,9.06?A/cm~2,and6.47 W/m~2,respectively.The output power density of this device is five times that of the nanogenerator based on pure PDMS film.This work provides a better understanding of material problems affecting TENG's surface charge density from the device physics perspective and provides an effective way to fabricate materials with high triboelectric performance.On the other hand,to reduce the mechanical abrasion of sliding mode TENG,the centrifugal force is employed to induce working mode transition automatically by the built-in traction rope structure.Combined with the theoretical analysis of the structure model at mechanical equilibrium and the structural parameters of the traction rope,the threshold speed of mode transition turns out to be adjustable.This designed device has excellent stability in output performance,maintaining 90%of the power output during continuous operation for 24 hours,while contact mode and non-contact mode TENG only maintain 30%and 2%in output,respectively.It provides an effective solution to solve the mechanical abrasion of sliding TENG,greatly expanding the working frequency and application range.(2)Hybrid energy devices:according to the advantages of TENG in low-frequency energy acquisition,the hybrid power generation device combined with traditional electromagnetic induction generator(EMG)can harvest wide-frequency energy with high efficiency.In this work,a cylindrical hybrid generator based on TENG and EMG was designed for the rotation energy in the vertical direction,and the effects of rotating speed on the output performance of TENG and EMG were studied from the theoretical calculation and experimental measurement.The mechanical abrasion of traditional sliding mode TENG can be effectively avoided by using a magnet to stimulate the contact-separation mode TENG units located on the cylindrical cavity's wall,and the unique structure without rotating shaft is easy to realize full-package of devices.The device can maintain stable output after working continuously for 75 h at 320 rpm and soaking in water for 1 h.Moreover,it has been successfully applied to collect the rotating energy of automobile tires and the sustainable energy supply of wireless sensors.This strategy achieves the functionalization of 1+1>2 for the hybrid devices based on TENG and EMG units.In addition,due to the pulse output of TENG,energy storage devices are needed to construct a self-charging power unit to charge electronics continuously.In this section,utilizing the traditional textile technology,a self-charging power fabric based on the integration of TENG and supercapacitor was designed for the energy of human movement.The effects of yarn's diameter and working frequency on TENG output were investigated experimentally.Using ruthenium oxide coated carbon fiber,the supercapacitor formed in the weaving process has extremely high mechanical and electric stability.This self-charging power fabric has great potential in wearable electronics.(3)Sensor design and application:as a new type of mechanical sensor,TENG has the characteristics of high sensitivity,flexibility,diverse structure and self-power.Considering that sliding TENG based barcode could not accurately decode the information at random speeds,a reference electrode was introduced to provide a calibration signal.Moreover,combining threshold value,phase difference and finding peak,a new coding method was proposed.This method can be used not only to control the access control system,but also to obtain 2D barcode identification systems with more information by increasing the number of columns and reducing the size of barcode.This work opens up the application prospect of TENG in information security field.Besides,TENG has capacitive output characteristics with high voltage and low current,which has been proven to be a safe high voltage power source.In this section,a strategy for actuating cantilever beam that converts low-frequency mechanical motion into high-frequency oscillation by periodically establishing and neutralizing the high DC voltage during the operation process of free-standing mode TENG.This DC actuating strategy is significantly different from the AC exciting method which requires the working frequency matches intrinsic frequency of cantilever beams.And a single-electrode TENG integrated on one side of the cantilever beam is employed to replace the commercial micro-distance meter(72 m V/mm)for real-time vibration monitoring,with a sensitivity up to 223 m V/mm.Finally,the integrated actuating and sensing cantilever system has been successfully worked as a self-powered micro-weighing system to measure the objects at the cantilever tip with micrograms precision.This work shows significant advantages in using TENG for both power and sensing in the micro-electro-mechanical system.