Researchers at the University of California, San Diego have developed a new device that can harvest energy from sweat on the fingertips, and can even generate electricity while sleeping.
This device is wrapped around the tip of the finger like a band-aid, which converts the chemicals in human sweat into a small amount of electricity. Since the fingers continuously produce sweat, the device can work without the wearer’s movement.
Joseph Wang, a professor of nanoengineering at the University of California, San Diego, said: “By using the sweat on your fingertips-no matter where you are or what you are doing, it will flow out naturally-this technology provides users without any effort. Net energy.”
Since this device does not require any physical input from the wearer to work, it “takes a step towards making wearable devices more practical, more convenient, and more accessible to ordinary people,” the research report’s co-author, California Lu Yin, a PhD student in the Department of Nanoengineering at the University of San Diego, said in a statement. Researchers at the University of California, San Diego have previously studied temporary tattoos that convert sweat into electricity.
The researchers said that the device may power low-power electronic products that work in the milliwatt range, such as smart watches, but it is not yet suitable for continuous power supply of high-performance electronic products, such as smart phones.
Yin said: “Our goal is to make this a practical device. We want to show that this is not just another cool thing that can generate a small amount of energy, and then that’s it. We can actually use this energy to do Power supply for useful electronics, such as sensors and displays.”
Everyone’s fingertips have more than 1,000 sweat glands, which can produce 100 to 1,000 times more sweat than most other parts of the body. However, it may be difficult for you to notice how much they sweat, because sweat usually evaporates from your fingertips as soon as it comes out, and this new device collects it before it evaporates.
IT Home learned that the device is an energy harvester called a biofuel cell, powered by lactic acid (a compound dissolved in sweat). From the outside, it is a thin and soft band, about 1 square centimeter in size, which can be wrapped around the fingertips like a band-aid, and can be worn comfortably for a long time. The material of the device is foam made of carbon nanotube material, and there is also a hydrogel that helps maximize sweat absorption.
The pad of the carbon foam electrode fits tightly to the finger, absorbs sweat and converts it into electrical energy. Electrodes are equipped with enzymes that can trigger a chemical reaction between lactic acid and oxygen molecules in sweat to generate electricity. Under the electrodes is a chip made of piezoelectric material, which generates additional electrical energy when squeezed.
When the wearer sweats or presses his finger, the electrical energy is stored in a small capacitor and released to other devices when needed.
A subject wore the device at his fingertips and slept for 10 hours. The device collected 400 millijoules of energy, which is enough to provide an electronic watch (but not a smart watch) with energy for 24 hours. Researchers pointed out that tying the device to more fingertips will generate more energy.
In addition, the device can read the body’s vitamin C level and the sodium ion level in the saline solution.