Scientists from Nanyang University of Technology in Singapore (NTU Singapore) have developed an extensible and waterproof “fabric” that converts energy generated by body movements into electricity.
A crucial component in the fabric is the polymer, which when pressed or pressed converts mechanical stress into electrical energy. It is also made of stretchable spandex as a base layer and integrated with a rubber-like material to be strong, flexible and waterproof.
In an experiment to prove the concept, reported in a scientific journal Advanced materials in April, the NTU Singapore team showed that tapping a piece 3 cm by 4 cm of new fabric generates enough electricity to turn on 100 LEDs.
Washing, folding and creasing the fabric does not cause any deterioration in performance and can maintain a stable electrical power for up to five months, demonstrating its potential for use as a smart textile and wearable energy source.
Materials scientist and associate rector of NTU (graduate) Professor Lee Pui Xi, who led the study, said: “There have been many attempts to develop fabrics or clothing that can collect energy from movement, but the big challenge was to develop something that does not impair its functions after washing and at the same time retains excellent electrical power. In our study, we demonstrated that our prototype continues to function well after washing and squeezing. We believe that it can be woven into T-shirts or integrated into the soles of shoes to collect energy from the smallest movements of the body, supplying electricity to mobile devices. “
Collecting an alternative energy source
The electricity generation board, developed by the NTU team, is an energy collection device that converts the vibrations produced by the smallest movements of the body in everyday life into electricity.
Prototype fabric produces electricity in two ways: when it is compressed or crushed (piezoelectric) and when it comes into contact or friction with other materials, such as leather or rubber gloves (triboelectric effect).
To produce the prototype, the scientists first made a stretchable electrode by screen printing on “ink” containing silver and styrene-ethylene-butylene-styrene (SEBS), a rubber-like material found in teethers and handlebars to make it. more stretchable and waterproof.
This stretchable electrode is then attached to a piece of nanofiber fabric, which consists of two main components: poly (vinylidene fluoride) –co-hexafluoropropylene (PVDF-HPF), a polymer that produces an electric charge by compression, bending or stretching; and lead-free perovskite, a promising material in the field of solar cells and LEDs.
NTU PhD student Jiang Feng, who is part of the research team, explained: “The incorporation of perovskites into PVDF-HPF increases the electrical power of the prototype. In our study, we chose lead-free perovskites as a more environmentally friendly option. While perovskites are fragile in nature, their integration into PVDF-HPF gives the perovskites exceptional mechanical strength and flexibility. PVDF-HPF also acts as an additional layer of perovskite protection, adding to its mechanical properties and stability. “
The result is a prototype fabric that generates 2.34 watts per square meter of electricity – enough to power small electronic devices such as LEDs and commercial capacitors.
Proving the concept
To demonstrate how their fabric prototype could work, NTU scientists have shown how a single tap on a 3cm by 4cm piece of fabric can continuously light 100 LEDs or charge various capacitors, which are devices that store electricity and are in the devices. such as mobile phones.
The fabric showed good durability and stability – its electrical properties did not deteriorate after washing, folding and squeezing. It also continued to produce continuous stable electric power for up to five months.
Scientists have shown that their tissue can use energy from a number of human movements by attaching it to the arm, leg, arm and elbow, as well as to the insoles of shoes, and did so without affecting the movements.
Professor Lee said: “Despite improved battery capacity and reduced power consumption, wearable power sources still require frequent battery changes. Our results show that our prototype energy collection fabric can use human vibrational energy to extend battery life or even to build self-powered systems. As far as we know, this is the first hybrid energy device based on perovskite, which is stable, stretchable, breathable, waterproof and at the same time able to provide exceptional electrical performance. “
This tissue-based energy collection prototype is based on the work of the NTU team, which looks at how energy generated in the environment can be cleaned up. For example, the team recently developed a type of film that could potentially be mounted on roofs or walls to harness the energy produced by wind or raindrops falling on the film.
The team is now looking at how the same tissue can be adapted to collect different forms of energy.