Structural Design Of Single-Electrode Triboelectric Nanogenerators And Applications In Self-Powered System

With the advent of the information age and the rapid development of the Internet of Things technology,sensing devices with various functions have been widely used in our production and life,such as health monitoring,intelligent transportation,smart home,environmental protection,video monitoring,industrial safety,etc.,which require a large number of sensors to provide various signal support.At present,most wireless sensors are still powered by batteries.However,for huge wireless sensor networks such as the Internet of Things,due to the large number and wide distribution of sensors,the use of traditional battery power needs to replace battery frequently,which costs a lot and will cause environmental problems.Self-powered sensing is a new sensing method that can obtain energy from the environment without external power supply,which provides a new solution to the sensor power supply problem in the Internet of Things technology.On the one hand,as a device to harvest mechanical energy,triboelectric nanogenerator(TENG)can harvest all kinds of mechanical energy and convert it into electric energy to power other electronic devices.On the other hand,triboelectric nanogenerator can also be used as self-powered sensors because of their sensitivity to environmental disturbance.In this paper,new single-electrode triboelectric nanogenerators with different structures and working modes are designed and constructed for different application.Through theoretical analysis and experimental results,the working mechanism,output performance and self-powered sensing applications of the single-electrode triboelectric nanogenerators are studied.The main research work and contents of this thesis are as follows:(1)Here,a single-electrode tube-based triboelectric nanogenerator was designed for self-powered sensing of pipe blockage and pressure changes.By collecting and monitoring the electrical signals generated by the triboelectric nanogenerators in real time,the self-powered sensor can be used not only to monitor the flow rate and position of water,but also to locate the location of pipeline blockage.In addition,by extending the electrode of the tube-based nanogenerator and combining it with a balloon,the realtime monitoring air pressure changes without external power supply is realized in the experiment.When the pressure changes,the water column in the PTFE pipe will move up or down,thus the device will generate different electrical signals.According to the relationship between the electrical signals and the pressure changes,the real-time pressure changes can be obtained.Due to its low cost,flexible and simple structure,the tube-based triboelectric nanogenerator has potential application value in fluid dynamic monitoring,pipeline maintenance and safety monitoring.(2)Active trajectory tracking of moving objects is one of the basic conditions for the interconnection of all things.Therefore,a single-electrode triboelectric nanogenerator based on a conductive sponge(CS)was designed,which can harvest mechanical energy in dual mode and be used as self-powered sensor.The device can work in both vertical contact-separation and laterial sliding mode,and sense the change of pressure above the nanogerator with a higher voltage signal output.It has the advantages of fast response,high sensitivity and good environmental adaptability.In addition,a trajectory tracking sensor matrix was formed by several sponge-electrode triboelectric nanogerator units.By recording the output electrical signal of each small unit,the trajectory of people or objects moving on the sensor matrix can be monitored and recorded in real time.The whole process does not need any external power supply,which truly realizes the self-powered sensing.This study also shows that the singleelectrode triboelectric nanogenerator has potential application in self-powered trajectory tracking.It also provides a new way for the development of intelligent technology in the future.(3)In the process of harvesting human energy,how to lay electrode is often a difficult problem to solve.Here,two single-electrode triboelectric nanogenerators based on human body electrode was constructed,and their applications in human mechanical energy harvesting and self-powered sensing are studied.On the one hand,it can effectively harvest the biomechanical energy generated in the process of walking and running,and convert it to electricity to power other devices.On the other hand,it can be used as a self-powered multi-functional body physical sign monitor.More importantly,it does not need any conductive metal electrode.The self-powered device does not need any external power supply,and can extract electrical signals from any part of the human body to obtain the information of human gait,lameness,weight(weight),jumping height and so on,and transmit the signals actively.This work provides a new self-powered route of health surveillance and disease diagnosis.(4)Harvesting energy from human body in multiple ways is pivotal for achieving powering emergency electronics effectively.Herein,we report a hybrid nanogenerator that is based on the coupling of a triboelectric nanogenerator and electromagnetic generator(EMG).By utilizing a copper coil in multi roles,the energy grabbing units can operate independently without interfering,revealing a superior performance in scavenging biomechanical energy from human motions.The hybrid device by encapsulation exhibits an excellent environmental stability.When wearing the fabricated device,the TENG and EMG can generate the output voltage about 4 and 1.5V,respectively,which can be directly stored into a capacitor.By integrating with a battery,the established self-powered device can actively provide a geographic coordinate in real time in the wild where there is no power supply or network connectivity.The work paves a way for the further exploration the self-powered wearable/portable emergency electronics.(5)Respiratory protection and monitoring is an important aspect of human health protection.Here,a new smart antimicrobial mask with a breath-driven TENG structure was fabricated to achieve dynamic monitoring of respiratory metrics while improving overall protection.The mask applies activated carbon fiber cloth(ACFC)with deposited silver nanowires(AgNWs)and electrostatically spun fibers(PVDF)to drive the interstitial periodic changes of the material during breathing to achieve electrostatic charge transfer.In filtration tests,the structure can achieve up to 98.3% and 96.5%filtration efficiency for PM2.5 and PM0.5,respectively.Meanwhile,under actual wear,the frequency,intensity and coughing of breathing can be monitored in real time.In addition,the deposited AgNWs show effective inhibition of different strains of bacteria.This part of the work presents an effective composite solution for and air filtration and wearable respiratory sensing,which is of great importance for modern healthcare.