| Energy shortage and environment pollution have become the two common challenges facing the world.Exploring advanced techniques to develop clean renewable energy is a key approach to solve the problems.The invention of triboelectric nanogenerator(TENG)promotes the effective collection of ambient mechanical energy.TENG has emerged as one of the front research topics in renewable energy field and extensive research has carried out in self-powered applications.Especially in the development stage of information society,investigations on self-powered sensors can promote Internet of Things(IoT)towards directions of smart,energy-conservation and intelligent.Besides,the self-powered system is another main promising application of TENG.To control environment pollution by clean approach should be further studied for achieving energy saving and emission reduction target.In this dissertation,the research focuses on ambient mechanical energy efficiently harvesting technology.Several types of TENG have been proposed as human motion energy and wind energy harvester.Materials selection,structural optimization and integration have been made to improve output performance,durability and adaptability of devices.Based on the work principle of TENG,applications in self-powered sensors have been investigated.It has realized fast response,high accuracy,multifunctional,active sensing which drives the development of IoT.In addition,the new type of self-powered air purifier based on triboelectric effect has been developed.Through using high output voltage,it can achieve self-powered air particulate matter removal,which settles the power supply difficulties of traditional air purification method and reduces purification period.Applications in industry waste gas,traffic exhaust,everyday life air cleaning have been shown.The details of this dissertation are described as below:A novel self-recovering TENG(STENG)driven by airflow is designed by assembling a spring to decrease mechanical energy consumption in the recovery process.Output voltage and current of the device driven by airflow is about 251 V and 56 ?A,respectively,corresponding to output power of 3.1 mW.Output performance of the STENG in various gas conditions has been measured and the reason has been analyzed.It can act as active multifunctional sensors to detect humidity and flowrate with a wide humidity detection range of 20%?80%,rapid response time of 18 ms,and recovery time of 80 ms.Besides,it can be utilized in security monitoring system to realize visualization detection,which is able to generate voltage signal to directly light up warning lights when triggered by motion.This work expands practical applications of TENG as active sensors in environment monitoring,security service and emergency response applications.A flexible array-mode TENG(FATENG)using low dimensional conductive fiber as electrodes is developed for obtaining high-flexibility and high-resolution device.Based on the triboelectric mechanism,FATENG can be utilized as the self-powered pressure sensor with no external power supply needed.The resolution of the device is 127 × 127 dpi,which is over 10 times higher than mechanoreceptors in biologic skin.The response time of pressure sensing is 68 ms and the sensitivity is 0.055 nA/KPa.With excellent flexibility,it can be adhered on curved surfaces for pressure sensing purposes.In addition,FATENG is used in high-resolution pressure sensing to real-time map pressure trajectory.Notably,there is a significant reduction in test channels due to crossing electrodes design.This work has wide applications in electronic skin,human-machine interaction and wearable electronics.A triboelectric-piezoelectric-pyroelectric multiple effects coupling nanogenerator is proposed with a sandwich structure.It performs excellent antibacterial property through surface modification method.By virtue of triboelectric-piezoelectric and pyroelectric effect with different response time,it can serve as self-powered multifunctional tactile sensor to detect pressure and temperature.The accurate correction equation has been presented and its veracity has been validated through comparing calculated and actual values.The tactile sensor can achieve real-time tactile monitoring of external objects on curved surfaces.Furthermore,the spatially resolved sensing ability has also been investigated.This work can be a reference for designing energy harvesting devices,which may become promising candidate in human-machine interaction,soft robotics,artificial prosthetics and healthcare monitors fields.A hybrid nanogenerator composed of a TENG and a thermoelectric generator(TEG)is developed.Both mechanical and heat energy of the exhaust gas can be recycled by combining the merits of two parts.The hybrid nanogenerator can deliver high voltage of 531 V,high current of 148.7 mA.Dependence of output performance on structure dimension and gas situation has been analyzed.After connecting with a power management circuit,it delivers a regulated voltage of 5.2 V.Thus it can serve as a sustainable power source of electronic products,such as lighting up LEDs,powering a mobile phone and charging capacitors.This work has wide potential application prospects in large-scale industrial exhaust gas recycle area.Two types of air purifier based on triboelectric effect are designed.The self-powered electrostatic precipitating system makes use of a TENG to offer 74?z/400 V high frequency and high voltage electricity for removing particulate matters.Impacts of particulate matter concentration,size and precipitation time on purification performance have been investigated.For initial concentration of 671?g/m3,it obtains high removal efficiency of 92.1%for PM2.5 after continuous work of 6 h.The ultralight-instaneous air purifier is proposed with a novel three-dimensional multipath spatial structure.Benefiting from the triboelectric effect of foam spheres,high electrostatic field is spontaneously generated to in-situ absorb particulate matter.So the purification period can be shortened.When the initial concentration is 1192 ?g/m3,the PM 2.5 removal efficiency is up to 96.3%.In vehicle exhaust filtration test,it presented a high removal efficiency of 98.0%for PM2.5.In addition,a mobile active-supply air purification system has also been developed for clean and effortless breathing in haze conditions.This research brings a new purifying approach,which can be applied in various areas including traffic exhaust treatment,industrial waste gas control and mobile purification. |
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