Structural and Electrical Dynamics of a Grating-Patterned Triboelectric Energy Harvester with Stick-Slip Oscillation and Magnetic Bistability

The majority of research work on triboelectric energy harvesting is on material science, manufacturing and electric circuit design. There is a lack of in-depth research into structural dynamics which is crucial for power generation in triboelectric energy harvesting. In this paper, a novel triboelectric energy harvester with a compact structure working in sliding mode is developed, which is in the form of a casing and an oscillator inside. Unlike most sliding-mode harvesters using single-unit films, the proposed harvester utilizes grating-patterned films which are much more efficient. A bistable mechanism consisting of two pairs of magnets is employed for broadening the frequency bandwidth. A theoretical model is established for the harvester, which couples the structural dynamics domain and electrical dynamics domain. This paper presents the first study about the nonlinear structural dynamics of a triboelectric energy harvester with grating-patterned films, which is also the first triboelectric energy harvester integrating grating-patterned films with a bistable magnetic system for power performance enhancement. Theoretical studies are carried out from the perspectives of both structural and electrical dynamics. A comparison between the coupled model and uncoupled model reveals that the electrostatic force between the electrodes can be neglected. Great differences in structural response and electrical output are found between a velocity-dependent model and Coulomb’s model for modelling the friction in the harvester. The bistable mechanism can effectively improve the output voltage under low-frequency excitations. Additionally, the output voltage can also be obviously enhanced through increasing the number of the hollowed-out units of the grating-patterned films, which also results in a slight decrease of the optimal load resistance of the harvester. These findings enable innovative designs for triboelectric energy harvesters and provide fabrication guidelines in practical applications.

Triboelectric energy harvesting by conjugated microporous polymer nanoparticles in polyurethane films

This work introduces, for the first time, the energy harvesting performance of conjugated microporous polymers (CMPs) as tribo-positive materials for triboelectric nanogenerators (TENGs). Various nano or sub-micron CMP particles (CMP-X)...

Challenges of Coating Textiles With Graphene

Electronic textiles (e-textiles) hold the key for seamless integration of electronic devices for wearable applications. Compared to other flexible substrates, such as plastic films, textiles are, however, challenging substrates to work with due to their surface roughness. Researchers at the University of Exeter demonstrated that using different coating techniques as well as different types of graphene coatings is the key to overcome this challenge. The results of coating selected monofilament textile fibres and woven textiles with graphene are discussed here. These conductive textiles are fundamental components e-textiles, and some applications will be reviewed in this paper. That includes light-emitting devices, touch and position sensors, as well as temperature and humidity sensors. The possibility of triboelectric energy harvesting is also discussed as the next step to realise self-powered e-textiles.