For the first time, fabric can use the energy of human movement and chemicals in sweat to charge electronic devices
It is not the first time fabrics can generate electricity. Recently, a thin and transparent film was created that absorbs sweat and converts it into electrical energy that can charge smart watches. But this time, you will have to sweat.
A team of researchers from the University of San Diego in California, USA took another step forward. They created a fabric that uses kinetic energy and chemicals in sweat to charge devices with liquid crystal displays (such as battery-powered watches). In this case, the CASIO brand watch only needs three minutes of exercise to start charging.
This design is called an electronic textile microgrid system, which refers to portable electronic products.Its details are Recently published in the journal Nature.
What it takes to turn sweat into energy
Many batteries already contain portable charging systems. An example of these mechanisms is the triboelectric generator (TEG), which generates energy through movement. Microbial biofuel cells (BFC) that generate energy from sweat are also often used.
The generated electrical energy is usually stored in batteries or supercapacitors (SC). Especially the latter stands out with its flexible download rate. In other words, they can continuously power low-power devices or temporarily power high-power devices.
So far, there has not been a design that has all the mechanisms considered at the same time like San Diego. Researchers have connected TEG generators and biofuel cells to supercapacitors to apply them to sportswear.
According to the researchers, connecting the TEG generator to the BFC battery can compensate for the limitations of the two systems. The first balances the slow start of the second (it requires sweat to generate energy), and the second continues to generate energy even if the movement has stopped.
Shirt charging the watch
In order to make the different modules portable, they have been designed as printed fabrics. The different modules are interconnected by silver, which is also printed and protected by plastic. This protection makes the material waterproof while maintaining its flexibility.
Following these guidelines, the TEG generator is integrated into the forearm and torso of the T-shirt, where movement occurs. For its part, the BFC biofuel cell is placed inside the shirt to come into contact with sweat.
Place components in these parts to prevent them from deforming. To verify its effectiveness, the fabric was subjected to constant friction and passed through more than 2,000 washing machine cycles for 20 minutes without damage.
On the other hand, in order to check the operation of the system, different volunteers used this shirt while exercising on a bicycle machine. It only needs to move for three minutes and it can continuously power the watch. If the exercise lasts for a longer period of time, reaching ten minutes, then the load is sufficient to sustain it for 30 minutes.
The researchers also conducted simulations to test the effectiveness of their system to charge more power-hungry devices, making the system an attractive example of future clothing. As they pointed out, it can also be applied to small energy systems, such as chips, which require thermal, chemical or mechanical energy to meet the needs of various electronic applications.