Onion skin brings tears of joy
doi:10.1038/nindia.2017.141 Published online 18 November 2017
Onion skin thrown away as kitchen trash could now be a source of joy — helping produce electricity that can power smart electronics, according to researchers at the Indian Institute of Technology, Khargapur.
Working with scientists from South Korea, the researchers have found that the self-aligned cellulose fibrous onion skin could be a promising bio-piezoelectric material for fabricating nanogenerators that converts kinetic energy into electrical power1. The piezoelectric nanogenerators (PNG) fabricated from onion skin could convert vibrational and mechanical sources, such as body movements, wind flow and even machine vibrations, into electricity.
Commercially available piezoelectric materials may be toxic, non-biocompatible or complex to make. For biomedical health monitoring, PNG device should be non-toxic and biocompatible. "The novelty of our work lies in directly utilizing onion skins without any chemical treatment, as an efficient piezoelectric material that is biocompatible," the scientists report.
Experiments showed that a single onion skin based PNG could generate enough power to light 30 green LEDs. Six such units connected in series produced 106 volts of electricity. "If we can design our devices in series under a treadmill, dance floor, and shoe-rubber, it can easily harvest green energy during walking or running," they report.
Onion skin could be a very promising bio-piezoelectric material to make self-powered nanogenerators as alternative green energy resources for powering different smart electronic devices. This could also be used in large scale industrial applications.
In India these PNGs could be very helpful to generate electricity especially in villages, says Bhanu Bhusan Khatua, IIT-K professor and one of the authors.
1. Maiti, S. et al. Bio-waste onion skin as an innovative nature-driven piezoelectric material with high energy conversion efficiency. Nano Energy 42, 282-293 (2017) doi: 10.1016/j.nanoen.2017.10.041