Triboelectric/Piezoelectric Nanogenerator Based Respiratory Protection And Dynamic Sensing

For a long time,there have been a large number of different forms of mechanical energy in the natural environment.The birth of nanogenerators has made this phenomenon show extraordinary value in today’s rapid development of the renewable energy revolution and passive sensing.Including friction nano generators(TENG),piezoelectric nano generators(PENG)and pyroelectric generators,etc.Nano generators can convert various forms of mechanical energy into electrical energy,with simple structure,wide range of materials and wide application range,High energy conversion efficiency and other advantages,continue to play an increasingly important role in the field of environmental energy harvesting.After years of research,nano-generators can be applied to various forms of environmental energy,and the collected electric energy can be used to power small electronic devices or self-driving sensors.However,nano-generators still have some shortcomings,including biology.The energy involved is less,the output characteristics are unstable,and the actual social needs are not closely integrated.The research on nano generators with practical needs,diversified functions and excellent performance has become the focus of related research.Starting from the above perspectives,this thesis designs three different forms of nano-generators,and effectively applies them to a variety of actual demand scenarios.While improving the performance of nano-generators,it expands its application range.The specific main points of this thesis are as follows:(1)A new air filter with a breath-driven TENG structure is designed to improve the electrostatic adsorption efficiency of haze.The air filter consists of conductive sponges(CS)and nanofibers(NFs),which utilize the difference in gas resistance of the two materials to achieve contact and separation at the interface during breathing,and thus achieve a continuous supply of electrostatic charge.The charge transfer capability was investigated through a series of electrical tests,and the open circuit voltage of both was up to 28 V and remained stable for a long time.The influence pattern of several factors on the filtration efficiency was investigated by varying different conditions.At a flow rate of 10 L/min,the filter could achieve a PM2.5 blocking efficiency of 98% and a PM0.5 blocking efficiency of91.5%,significantly exceeding the level of commercial masks,while the TENG structure also showed a more significant filtration capability compared to electrostatic spun fibers alone.This part of the work provides a novel and efficient solution for enhancing the filtration level of submicron particles.(2)A flexible self-powered piezoelectric sensor(PES)made of graphene-doped polyvinylidene fluoride(PVDF)nanofibers is proposed.PES has high sensitivity to compression and bending,and there is a stable correlation between the bending angle and the piezoelectric voltage.The sensitivity can be adjusted by changing the graphene doping concentration.When the PES contacts the heat source,a pyroelectric signal can be obtained.The positive correlation between temperature and signal can be used to avoid burns.The comprehensive perception system based on multiple PESs can accurately recognize the movements of each finger in real time,and can be effectively used in sign language translation.PES-based motion tracking applications have been effectively applied,especially in human-computer interaction,such as gesture control,rehabilitation training,and auxiliary communication.(3)An in-plane sliding TENG is constructed and implemented for sensing applications of vector displacements in two-dimensional planes.The TENG is based on a tightly fitting sliding structure composed of aluminum(Al)and polytetrafluoroethylene(PTFE),and the charge transfer is realized during the sliding process based on the principle of frictional electricity.The electrical performance of the one-dimensional sliding process is explored through a series of simulations and basic electrical performance tests with an open-circuit voltage up to 11.6 V.In the single-electrode mode,the influence law of the output is explored in tests on relative size,velocity,and pressure,further revealing the working mechanism of the sliding TENG.In the one-dimensional multi-electrode case,the efficient and stable positioning performance of the TENG was verified under equal/non-equal spacing and changing sliding speed.Based on the findings,two two-dimensional planar sliding sensing models,corresponding to pen touch and handwriting,were designed and fabricated,showing good localization ability during both point touch and sliding.This work expands the application of TENG in human-machine interface and Internet of Things.