E-textile technology review - from materials to application

Wearable devices are ideal for personalized electronic applications in several domains such as healthcare, entertainment, sports and military. Although wearable technology is a growing market, current wearable devices are predominantly battery powered accessory devices, whose form factors also preclude them from utilizing the large area of the human body for spatiotemporal sensing or energy harvesting from body movements. E-textiles provide an opportunity to expand on current wearables to enable such applications via the larger surface area offered by garments, but consumer devices have been few and far between because of the inherent challenges in replicating traditional manufacturing technologies (that have enabled these wearable accessories) on textiles. Also, the powering of e-textile devices with battery energy like in wearable accessories, has proven incompatible with textile requirements for flexibility and washing. Although current e-textile research has shown advances in materials, new processing techniques, and one-off e-textile prototype devices, the pathway to industry scale commercialization is still uncertain. This paper reports the progress on the current technologies enabling the fabrication of e-textile devices and their power supplies including textile-based energy harvesters, energy storage mechanisms, and wireless power transfer solutions. It identifies factors that limit the adoption of current reported fabrication processes and devices in the industry for mass-market commercialization

Dielectric-metal triboelectric nanogenerators for ocean wave impact self-powered applications

This paper describes the effect of oscillatory frequencies caused by ocean wave impact on the output performance of dielectric-metal contact separation mode triboelectric nanogenerators (DMCS-TENG). The triboelectric effect is generated as a result of regular, non-uniform contact between a dielectric layer which gains electrons (negative triboelectric material) and a conductive layer that loses electrons (positive triboelectric material). Impact testing was used to characterize arc-shaped dielectric-metal single electrode triboelectric nanogenerators (DMSE-TENG) with different triboelectric material combinations based in their output power generation, using a 40 mm ball bearing to apply a 12 N force impulse. It was found that the best dielectric-conductor combination for the DMCS-TENG performance was polyimide and PDMS in contact with the conductor layers of aluminium and silver conductive cloth tape. Therefore, in the range of operation from 30 Hz to 300 Hz with an amplitude acceleration of 319.62 to 559.29 mm/s2. The maximum generated output power, power density and total energy conversion efficiency of the device, made with polyimide and honeycomb patterned aluminium foil, can reach up to 778.43 μW, 12.16 μW/cm2 and 15.85 % respectively for a load resistance of 10 MΩ. The output power performance of the DMCS-TENG shows an enhancement by a factor of 2.3 with a honeycomb-patterned aluminium foil, by increasing the surface charge density between the layers in contact, relative to flat aluminium foil. Additionally, through the integration of the energy harvester prototype into a water wave generator tank. An output power density of 169.218 mW/m2 was reached, where it is expected to generate output power energy around 3.05 W, over an area of 18 m2 with wave sizes among 0.3 m to 4 m. This work demonstrates that the device can function as an energy harvesting mechanism for ocean wave sensing applications that require self-powering

Grid of hybrid nanogenerators for improving ocean wave impact energy harvesting self-powered applications

This paper describes an alternative approach for improving the output power performance for coastal wave impact energy harvesting systems, located at water-structure interfaces. This is achieved by simultaneously coupling the triboelectric and piezoelectric effects, exhibited in some materials. The use of finite element modelling, and experimental electrical characterization, enables the integration of hybrid devices into a breaking water wave generator tank. This provides a mechanism for simulating actual ocean wave conditions at low frequencies (0.7 Hz–3 Hz). Enhancements in the output performance by a factor of 2.24 and 3.21, relative to those obtained from using single triboelectric and piezoelectric nanogenerators, were achieved. This is demonstrated by evaluating the output current, voltage, transferred charge, and charging performance from a grid of up to four hybrid devices connected to capacitors of different capacitance values. Such hybrid devices were capable of powering a one-way wireless transmitter with a generated output power between 340.85 μW and 2.57 mW and sent a signal to a receiver at different distances from 2 m to 8 m. The research shows that such an integrated device can provide a promising mechanism for developing high-performance energy harvesting mechanisms for ocean wave impact to drive self-powered systems having an average power consumption of 1–100 mW. Further, it is estimated that through the construction of large water-hybrid nanogenerator-structure interfaces, output powers of approximately 21.61 W can be generated for powering networks of self-poweredsensing systems in smart large-scale applications

Wave impact energy harvesting through water-dielectric triboelectrification with single-electrode triboelectric nanogenerators for battery-less systems

This paper evaluates the effect of water-dielectric interfaces for wave impact energy harvesting at low frequencies (0.7 Hz–3 Hz) on the output performance of Water-Dielectric Single Electrode Mode Triboelectric Nanogenerators (WDSE-TENG). The triboelectric effect is generated between water (with a net positive charge) and a hydrophobic dielectric layer (with a net negative charge). Different WDSE-TENG configurations were tested using distinct hydrophobic materials. The water-fluorinated ethylene propylene (FEP) combination resulted in the best output performance. On the contrary, an output performance reduction by a factor of 3.53 was measured with seawater-dielectric interfaces. This can be compensated by increasing the contact area, with the best performance obtained using silicone rubber compound (Acetoxy, Elastomer) utilizing a WDSE-TENG with two-dielectric layer configuration. Employing seawater as a triboelectric material, the highest electrical output power and power density of 79.18 mW and 0.344 mW/cm2 was generated with a grid of WDSE-TENG, comprising five devices connected in parallel. The output voltage, current, transferred charge, stored energy and energy conversion efficiency (ECE) values of the grid of connected WDSE-TENG devices were compared against a single device. Such energy harvesters were able to power an ultrasonic range sensor and a one-way wireless transmitter for motion detection, distance measurement, and monitoring weather conditions. The stored energy and generated power were ~5.96 mJ and ~5.18 mW, respectively. Furthermore, the integration of the grid of WDSE-TENG with a power management control circuit (PMCC) is able to increase the output power and hence offer the potential to power up electronic devices with power consumption requirements between 1 mW and 100 mW. The results demonstrate that the grid of WDSE-TENG offers an innovative energy harvesting approach using water as a triboelectric material. The device can be used as an energy source for smart battery-less wireless sensing systems at water-structure interfaces in aquaculture (e.g. for fish detection or water level measurement) and weather condition monitoring

Water-Dielectric Single Electrode Mode Triboelectric Nanogenerators for Ocean Wave Impact Energy Harvesting

The effect of water wave impacts and breakdown on the output performance of Water-Dielectric Single Electrode Mode Triboelectric Nanogenerators (WDSE-TENG) has been evaluated. When water contacts a TENG consisting of a hydrophobic dielectric layer, the triboelectric effect is generated with a net negative charge on the dielectric material and net positive charge on the water surface. The hydrophobic dielectric materials, which show the highest electrical output performance in contact with water, were FEP, silicone rubber and polyimide. The average output power of each sample for a load resistance of 10 MΩ was found to be in the range 14.69 to 19.12 µW. The results demonstrate that WDSE-TENG devices can work as an alternative energy harvesting mechanism by using water as a triboelectric material

A contact-separation mode triboelectric nanogenerator for ocean wave impact energy harvesting

This paper describes the effect of ocean wave impact compressed air bubbles on the output performance of a dielectric-metal contact separation mode triboelectric nanogenerator (DMCS-TENG). The triboelectric effect is generated by regular, non-uniform contact between a negative polyimide dielectric layer of easy gaining electrons and positive Aluminum foil of easy losing electrons according the triboelectric series, where the electrical performance changes in proportion to the mechanical energy applied by oscillatory frequencies. At the range of operation of 30 Hz to 300 Hz, the open-circuit voltage, short-circuit current, power and output power density of the device can reach to 3.83 V, 80.38 μα, 307.88 μW and 19.24 μW/cm2, respectively for a load resistance of 10 ΜΩ. The proposed work demonstrates that the device can function as an energy harvesting mechanism for ocean wave monitoring applications that require self-powering.</p