Water–based Nanogenerators generate energy from every human-movement in water

Apr, 2021 - By SMI

Researchers at the Chinese University of Hong Kong (CUHK) have created new compact nanogenerators that can extract energy from a range of motions, including ocean waves and human body movements.

The latest devices are triboelectric nanogenerators (TENGs), which use friction to produce electricity. Body motions, footsteps on flooring, touchscreen clicks, and even raindrops falling down solar panels have all been used to generate electricity. However, as the CUHK team points out, one of TENGs' biggest drawbacks is that they need sturdy surfaces to stay in touch for long periods of time, which can be difficult to maintain. The researchers used friction between a solid and a liquid to create the new device. Researchers poured deionized water into a finger-sized plastic conduit, which can create energy as it sloshes between two electrodes. The system is classified as a water-tube-based triboelectric nanogenerator (WT-TENG) by the researchers. The WT-TENGs have higher performance volumetric charge densities, according to the team, since the water can sustain contact with the electrodes more easily. It exceeds 9 Millicoloumbs per m3 at frequencies as low as 0.25 Hz, according to the researchers.

Zi Yunlong, corresponding author of the study states that, “Previous designs of ocean energy harvesters have been equipped with electromagnetic-based generators which are large in size and heavy, and will only generate power if the frequency of ocean waves reaches a certain high level,”

The team put the latter two of these configurations to the test in experiments. In one, the team combined 34 WT-TENG units into one box and floated it on the sea to collect wave energy, while in the other, they made a wristband out of 10 WT-TENGs. According to the team, this design has many benefits. Researchers don't need any other moving components, such as springs or rotors, and researchers can harvest energy from a number of motions. This implies that they may be useful for harvesting energy from a range of sources, such as float on ocean waves, sensors that mount to ships, or wearables that track a user's movements.