Triboelectric Nanogenerators: Design, Fabrication, Energy Harvesting, and Portable-Wearable Applications

Abstract

Scavenging energy from our day-today activity into useful electrical energy be the best solution to solve the energy crisis. This concept entirely reduces the usage of batteries, which have a complex issue in recycling and disposal. For electrical harvesting energy from vibration energy, there are few energy harvesters available, but the fabrication, implementation, and maintenances are quite complicated. Triboelectric nanogenerators (TENG) having the advantage of accessible design, less fabrication cost, and high energy efficiency can replace the battery in lowpower electronic devices. TENGs can operate in various working modes such as contact-separation mode, sliding mode, single-electrode mode, and free-standing mode. The design of TENGs with the respective operating modes employed in generating electric power as well as can be utilized as a portable and wearable power source. The fabrication of triboelectric layers with micro-roughness could enhance the triboelectric charge generation. The objective of this chapter is to deal with the design of triboelectric layers, creating micro structured roughness using the soft-lithographic technique, fabrication of TENGs using different working modes, energy harvesting performance analysis, powering up commercial devices (LEDs, displays, and capacitors), and portable-wearable applications.

Hybrid lead-free polymer-based nanocomposites with improved piezoelectric response for biomedical energy-harvesting applications: A review

“…A piezopolymer loaded with microstructured ceramics provided an improved output voltage [204] and an increased current output [49] when a sample of the nanocomposite was bent by the fingers. In the presence of composite ceramic NPs, a simple planar piezopolymer film exhibited a remarkably high open circuit voltage of ~160 V under a small constant mechanical force [31]. rGO and Gr nanosheets seem to be promising nanofillers for obtaining strong sensing capabilities with low detection limits [31,203,206], especially in combination with specific film geometries and a multilayered sensor structure [203].…”

“…In the presence of composite ceramic NPs, a simple planar piezopolymer film exhibited a remarkably high open circuit voltage of ~160 V under a small constant mechanical force [31]. rGO and Gr nanosheets seem to be promising nanofillers for obtaining strong sensing capabilities with low detection limits [31,203,206], especially in combination with specific film geometries and a multilayered sensor structure [203]. Good sensitivity was also obtained for microstructured piezopolymers loaded with metal oxides [200].…”

“…Loading nanofillers of various shapes and sizes ( Figure S4), including complex doped [19,31,45,55] and coated [59,76,208] fillers, into a piezopolymer matrix can efficiently increase its electroactive properties, while co-doping with several different types of nanofillers and optimising their content [27,209] will provide further improvements in sensitivity. Furthermore, the muchless-explored and -exploited microscale patterning and the alignment of nanofiller particles inside the piezopolymer matrix are significant steps towards tuning and controlling the material properties ( Figure S5).…”

“…The application of high voltages during the electrospinning process essentially leads to the alignment of the electric dipoles present in the PVDF solution, with the degree of alignment being proportional to the magnitude of the applied electric field [26]. Various electrospun hybrid composites for energy-harvesting applications based on PVDF or PVDF-TrFE nanofibre mats, including graphene nanosheets and BT NPs [27], (Na0.5,K0.5)NbO 3 (NKN) NPs embedded in PVDF-TrFE [12], BT NPs embedded in PVDF-TrFE [28,29], PVDF-ZnO nanofibre mats [26], PVDF/KNN NRs [30], K0.5Na0.5NbO 3 -BT/PVDF [31], Ag/PVDF-TrFE [32], and PVDF-TrFE-BT with rGO contents of 0.1%, 0.3%, 0.5%, and 0.7% [33] have been reported. Structurally robust, reproducibly scalable, substrate-independent, and large-area NGs have been successfully fabricated utilizing the near-field electrospinning direct-write technique to massively align the piezoelectric PVDF nanofibres (NFs) on flexible substrates [34].…”

“…Comparison of the piezoelectric constants (d33 and d31 , pC/N=pm/V) for PVDF-based PENGs. Comparison of the outputs of nanocomposite-based piezoelectric nanogenerators.Nanocomposites based on PVDF and its co-polymers and loaded with inorganic fillers are very promising for biomedical applications such as energy-harvesting devices.…”