University of Illinois researchers turned waste pomelo peels into self-powered devices that generate electricity and observes body movements, providing sustainable solutions for energy harvesting and healthcare.
Pomelo, a large citrus fruit broadly grown in Southeast and East Asia, has a appreciably thick peel that is commonly waste, contributing to considerable food waste. In a latest study, researchers at the University of Illinois Urbana-Champaign examined strategies to reuse this pomelo peel biomass to evolve tools suitable of powering small electronic gadgets and monitoring biomechanical movements.
“There are two foremost parts of the pomelo peel – a thin outer layer and a thick, white inner layer. The white part is soft and appears like a sponge while you push on it. Some people have used pomelo peels to extract compounds for essential oils or pectin, but we desired to take benefits of the herbal porous, spongy structure of the peel. If we are able to upcycle the peel for higher-value products rather than throwing it away, we can’t simply reduce waste from pomelo manufacturing, intake, and juice making, however also create more value from foods and agricultural waste,” stated researches co-author Yi-Cheng Wang, an assistant professor in the Department of Food Science and Human Nutrition, part of the College of Agricultural, Consumer and Environmental Sciences at Illinois.
A normal pomelo weighs between 1 and 2 kilograms (2 to 4.5 pounds), with the peel containing 30% to 50% of the entire weight. In their research, the researchers separated the peel from the fruit, removed the outermost layer, and then processed the thick white inner peel. They cut it into smaller portions and freeze-dried it to preserve its precise three-dimensional porous structure. These samples have been then saved beneath various humidity conditions for further analysis.
By examining the chemical composition and mechanical properties of the peel, the research group efficiently engineered devices that convert mechanical energy into electricity. These devices are functioned as self-powered motion sensors.
Harnessing Contact Electrification
“These devices influence the principle of contact electrification. That may also sound complicated, but it’s really quite simple and we experience it all of the time. For example, when we touch a doorknob, specifically in the winters, sometimes we feel a shock. The basic mechanism is contact electrification, or triboelectrification – ‘tribo’ meant rubbing. When two materials are rubbed towards each other, static electricity can form due to the transfer of charges between them. We wanted to explore if we may want to accumulate and make use of that electricity,” Wang stated.
The researchers used pomelo-peel biomass and a plastic (polyimide) film as two triboelectric layers that are added into contact when external force is present. They attached a copper-foil electrode to each of these layers and calculated how properly the resulting device should convert external mechanical energy into electricity.
By simply tapping those pomelo-peel primarily based triboelectric devices with a finger, they might light up about 20 light-emitting diodes (LEDs). They also demonstrated that a calculator or sports watch may be powered solely by means of those mechanical forces, without the need of external electricity, while the device is combined with a power-management management system that includes an energy-storage unit.
“This application has strong potential to convert otherwise wasted energy into beneficial electricity. We also located that, way to pomelo peel’s naturally porous structure, triboelectric devices based on it can be highly sensitive to force and force frequency. This inspired us to develop sensing devices that can be connected to the human body for biomechanical tracking,” Wang explained.
Tracking Human Motion and Future Implications
When connected to various body parts, the researchers’ proof-of-idea sensors were able able of display biomechanical movement such as joint motions and gait patterns. This was into because the movements of various body parts can lead to contact electrification among the triboelectric layers, producing wonderful electrical indicators corresponding to specific motions. This capability has amazing potential to provide valuable insights for healthcare and physical rehabilitation specialists.
“This work emphasize exciting chance to convert food waste into value-added devices and materials. By probably changing or supplementing non-renewable counterparts and decreasing waste, it could contribute notably toward long-time period sustainability, and we will continue exploring extra opportunities for upcycling foods and agricultural waste,” Wang stated.
The researchers have filed a provisional patent for their pomelo-peel based triboelectric devices.
