Human body "power plant"? Stable output for 5 months, easily lighting up 100 LED lights

Currently, as the product innovation of smartphones gradually weakens and the market capacity gradually approaches saturation, smart wearable electronic devices have become a new hotspot in the smart terminal industry.

Among them, flexible wearable electronic devices are one of the cutting-edge research directions in this field.

However, since the design and function of flexible wearable electronic devices have always been affected by the energy source and the materials used, there are not many amazing products on the market.

Wouldn’t it be cool if we could “throw away” bulky batteries and use our own energy to power wearable electronic devices?

Now, this idea may be becoming a reality.

Recently, research teams from Nanyang Technological University in Singapore and Tsinghua University jointly developed a stretchable waterproof "fabric" that can directly convert the energy generated by human body movement into electrical energy.

In a proof-of-concept experiment, the research team tapped a 3 cm by 4 cm piece of the experimental material and generated enough electricity to light up 100 LED lights.

Moreover, the performance of the fabric does not decrease after washing, folding and wrinkling, and it can even maintain a stable power output for up to 5 months.

The research team believes that this new fabric has the potential to become smart textiles and wearable power sources.

The related research paper, titled "Stretchable, Breathable, and Stable Lead-Free Perovskite/Polymer Nanofiber Composite for Hybrid Triboelectric and Piezoelectric Energy Harvesting", has been published in the scientific journal Advanced Materials.

A new alternative energy source

The new fabric is an energy-harvesting device that can convert vibrations generated by the tiniest body movements in everyday life into electricity.

According to the paper, a key component of the fabric is a polymer that, when pressed or squeezed, converts mechanical stress into electrical energy.

The new fabric consists of a stretchable spandex base layer integrated with a rubber-like material to keep it strong, flexible and waterproof.

"There have been many attempts to develop fabrics or clothing that can harvest energy from movement, but a big challenge is how to ensure that their functionality does not degrade after multiple washings while maintaining good power output," said Lee Pooi See, professor at Nanyang Technological University and the paper's corresponding author.

In this work, the research team demonstrated that the prototype fabric still works well after being washed and crumpled, and can be woven into T-shirts or integrated into shoe soles to harvest energy from the smallest movements of the human body and deliver power to mobile devices.

The new fabric generates electricity in two ways: when it is pressed or squashed, creating piezoelectricity, and when it is rubbed against other materials, such as skin or a rubber glove, creating a triboelectric effect.

To create the prototype fabric, the scientists first created a stretchable electrode by screen-printing an "ink" composed of silver and styrene-ethylene-butylene-styrene (SEBS).

The stretchable electrode was then attached to a nanofiber fabric made from PVDF-HPF, a polymer that generates an electrical charge when compressed, bent or stretched, and lead-free perovskite, a promising material for solar cells and LEDs.

The research team said that embedding perovskites in PVDF-HPF can increase the electrical output capacity of the prototype fabric, and lead-free perovskites are a more environmentally friendly option. PVDF-HPF not only gives perovskites special mechanical durability and flexibility, but also acts as an additional protective layer for perovskites, increasing their mechanical properties and stability.

No more batteries needed?

To demonstrate how their prototype fabric works, the team showed how a hand tapping continuously on a 3 cm by 4 cm piece of fabric could light up 100 LEDs or charge various capacitors.

The results showed that the new fabric exhibited good durability and stability - its electrical properties did not deteriorate after washing, folding and wrinkling, and it continued to generate continuous and stable power output for up to 5 months.

In addition, the new fabric can be attached to arms, legs, hands, elbows and insoles to harness the energy generated by a range of human movements without interfering with movement.

"Despite improvements in battery capacity and reductions in power demand, power sources for wearable devices still require frequent battery replacement. Our results show that our energy-harvesting prototype fabric can harness vibration energy from humans, potentially extending the life of batteries or even building self-powered systems. To our knowledge, this is the first perovskite-based hybrid energy device that is stable, stretchable, breathable, and waterproof while delivering excellent power output performance," said Lee.

The research team is currently investigating how to use the same fabric to harvest different forms of energy.

References:

https://www.ntu.edu.sg/news/detail/new-'fabric'-converts-motion-into-electricity

https://ersp.lib.whu.edu.cn/s/com/wiley/onlinelibrary/G.https/doi/10.1002/adma.202200042

https://www.reddit.com/r/science/comments/v5mlal/scientists_have_developed_a_stretchable_and/

https://www.sciencedaily.com/releases/2022/06/220603100146.htm