Aerogel And Nanofibrous Membrane Materials Based Single-Electrode Triboelectric Nanogenerator And Study On Their Self-Powered Sensing And Multi-Functional Applications

In current,the rapid development of the Internet of Things（IoT）,numerous wireless sensor networks,big data,robotics,and artificial intelligence are emerging.The explosive growth in the number of miniature smart sensors has created considerable challenges to energy demand,which far exceeds the capacity of traditional central power supply systems.Since the concept of triboelectric nanogenerator（TENG）is proposed in 2012,TENG exhibits a structural flexibility in self-powered systems,because of their high customizability and portability.In this thesis,four types of noval single-electrode TENGs are designed to adapt to more application scenarios.Their energy harvesting and self-powered sensing properties are explored,the main investigated content is as follows:1.Flexible and microwave protected MXene Ti₃C₂T_x aerogels signal-electrode triboelectric nanogenerator.Due to the coupling coordination of triboelectrification and electrostatic induction,the inherent porous and lightweight properties of aerogel are favorable to outstanding energy harvesting and microwave protection.MXene Ti₃C₂T_xaerogels are prepared by freeze-drying method with the assistance of carboxymethyl cellulose,which acts as a multifunctional group physical cross-linker to enhance the mechanical strength between MXene nanosheets.By adjusting the content of MXene Ti₃C₂T_x,the average electromagnetic wave protection performance of MXene/CMC2.5aerogel reach 52.15,60.31,and 80.36 d B in X,Ku,and K bands,respectively.Moreover,the MXene/CMC2.5 TENG exhibits an open-circuit voltage of 54.37 V,short-circuit current of 1.22μA,and power density of 402.94 m W m^-2 at the frequency of 5 Hz.And the TENG could easily drive light-emitting diodes（LED）under continuous tapping by bare fingers.The self-powered sensing is also verified.It has potential applications in the field of mechanical harvesting,health monitoring and microwave radiation protection,especially for pregnant women and frail elderly people.2.Stretchable and self-healing ionic-liquid elastomer（ILC）single-electrode triboelectric nanogenerators.In order to meet the application scenario of human health monitoring,the noval TENG needs excellent stretchability,flexibility,and mechanical damage resistance.The ionic liquid elastomer with physical cross-linked is prepared by the free radical polymerization method acting as a stretchable electrode layer.The complete ionic conducting pathway is fabricated in the ILC to transform charge.Moreover,the electrospun PVDF/PU nanofiber film is directly stacked on the surface of the electrode layer,which is used as the triboelectric layer.At an applied stress of 5N and an operating frequency of 5 Hz,the open-circuit voltage,short-circuit current,and power density reach 180.72 V,10.22μA,and 2.44 W m^-2,respectively.As the result illustrated that the energy harvesting performance of TENG remains constant after severe mechanical damage and prolonged washing.In addition,the durability,stability,and environmental tolerance are verified,the TENG could act as a self-powered sensor to monitor various human movements,physiological signals（such as ECG）,and tactile recognition.3.Hygroscopic and perspiration-wicking all-nanofibrous Janus fabric single-electrode triboelectric nanogenerator.As the self-powered electronic skin system,moisture accumulation has a devastating effect on the stability and reliability of monitoring signal at the skin interface.Inspired by the internal water transport in the plants,an all-nanofibrous Janus textile with dual gradient variation of pore size and hydrophilicity is fabricated using a continuous electrostatic spinning/spray technique under the assistance of adhesive layer,which also acts as a self-powered sensor to collect mechanical energy from the environment and monitor human motion/physiological signals.With an applied external force of 5 N and an operating frequency of 4 Hz,the open-circuit voltage,short-circuit current,and power density reach 78.10 V,0.16μA,and 3.31 W m^-2,respectively,and LED could be easily driven.In the wetted condition,the open-circuit voltage,short-circuit current,and power density can still reach 30 V,0.051μA,and 0.14 W m^-2,respectively.Moreover,the Janus fabric is used as a self-powered skin patch on the human body to monitor human movement and physiological signals demonstrating the excellent stability,sensitivity,and rapid responsiveness.4.Multi-hierarchical structured composite nanofibers single-electrode triboelectric nanogenerator.Using the tribovoltaic effect,the relative motion of triboelectric pairs forms built-in and interfacial electric fields at the interface to enhance the amount of interfacial charge transfer.In addition,the charge transfer process between multi-layered structured inorganic nanomaterials and organic materials also facilitates the energy harvesting of TENG.Nanoflower-like semiconductors are prepared by hydrothermal synthesis and then doped into PVDF nanofiber membranes to promote the formation of electroactiveβ-phase.Subsequently,a silver nanowire network is deposited on the surface of the PVDF hybrid nanofibers as an electrode layer by the electrospray method.Typically,（1）The flower-like P-type semiconductor NiO of 5 wt%is introduced into the electrospun PVDF polymer nanofibers,and the open-circuit voltage,short-circuit current,transferred charge,and power density of the TENG reach177.36 V,39μA,8.69μC,and 19.78 W m^-2 under the operating frequency of 4 Hz,respectively,（2）The flower-like N-type semiconductor ZnO of 5 wt%is introduced into the PVDF nanofiber,the open-circuit voltage,short-circuit current,transferred charge,and power density of the TENG reach 72.47 V,37μA,10.74μC,and 2.52 W m^-2 under the operating frequency of 4 Hz,respectively.The experiments also verify that the above-mentioned two TENGs are used as self-powered gait recognition sensors to analyze gait,monitor health,and warn slip.In summary,a series of noval single-electrode TENGs are designed in this article.The new function or property is provided through structural designing to suit more energy harvester/converter and self-powered sensor scenarios.These TENGs could efficiently harvest mechanical energy from the external environment or human motion to drive small electronic devices,and exhibit the excellent self-powered sensing.