Fish scales extracted from food waste have been used to build tiny generators that can convert mechanical energy, such as a touch or sound vibrations, to electrical energy. The work was done by physicists in India, who say that the piezoelectric device could be used to develop environmentally friendly, self-powered electronics with a wide-range of applications.
Piezoelectric materials respond to mechanical stress by separating positive and negative electrical charge, and therefore can be used to convert the mechanical energy of vibrations into electrical energy. Piezoelectric generators that harvest energy from vibrations in the living environment would allow the development of fully independent, battery-free devices. These could be particularly useful for medical devices, such as pacemakers and insulin pumps, and targeted drug-delivery systems that consume little power, but need it continuously.
But, to realize the full potential of such devices, researchers need to develop new environmentally friendly piezoelectric materials. Dipankar Mandal, a physicist at Jadavpur University in Koltata, India, says this is "simply because most of the traditional piezoelectric materials contain toxic elements, such as lead and bismuth". As well as being useful for biomedical applications, Mandal adds that non-toxic and environmentally friendly piezoelectric materials would also reduce electronic waste and society's dependence on traditional energy sources, like batteries, which often contain toxic elements.
