We all are familiar with Hydropower or hydroelectric power. It is a renewable source of energy that generates power from the motion of water. Like, water flowing over a waterfall to generate electricity. But, if you think of generating electricity from water drops, raindrops, water streams, and ocean waves, it might seem a new concept.
Researchers from IIT Delhi have recently designed and fabricated a device that can produce electricity from water drops, raindrops, water streams, and ocean waves using Triboelectric Effect and Electrostatic Induction. The device is known as ‘Liquid-solid Interface Triboelectric Nanogenerator’, which generates power and further stores the energy in batteries for consumption.
How does the device work?
The device works on the phenomena of Triboelectric Effect and Electrostatic Induction. The two concepts might be hard to understand, but in simple words, both postulates work on a simple concept of converting mechanical energy into useful electric power. For Example, when we rub a balloon on our head and slowly take it away from the head, the hair is attracted towards the balloon. So this real-life situation is also known as the Triboelectric Effect and uses Electrostatic Induction.
“Triboelectric effect is a known phenomenon for a long time, and in this effect, charges are generated when two surfaces are in friction. The best example we see is sparkling lights when we move the blankets/jackets. It is only lately that it has been extensively investigated as a practical alternative for energy harvesting,” said Prof. Neeraj Khare, Physics Department, IIT Delhi.
Similarly, the researchers used specially designed nanocomposite polymers and contact electrodes in the device to generate electricity. The incorporation of the nanostructures into a polymer matrix enhanced the film’s surface roughness, polarizability, and hydrophobicity, and other characteristics. As the properties of the film were enhanced, the flexible film was used to fabricate the device where raindrops can just slide down and can generate electricity.
Further, the artificially created rough surface allows the device to generate more charge from the droplet, and the superhydrophobic properties of the solid surface allow the water droplet to roll on the surface without getting stuck to the surface.
Impact of the device
The device with the above mechanism can generate a few Milliwatt (mW) power, which is sufficient to power small electronic devices like healthcare sensors, digital thermometers, watches, radio frequency transmitters, pedometers. When compared to conventional methods like the use of the piezoelectric effect, the ‘Liquid-solid Interface Triboelectric Nanogenerator’ can generate significantly more electricity in an effective manner.
The IIT Delhi research team also explored the underlying mechanism of the saline water drops, the team found that the Saline droplets generate more electricity compared to the normal water drops. The researchers also showed that the device can even work with ocean waves. As when the saline water of Ocean waves will contact the surface of nanocomposite polymer film, the device will produce electricity and the power will be stored in the batteries.3
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