“Give a man a fish, and he’ll eat for a day. Teach a man to fish, and he’ll eat for a lifetime. Give a man a pile of fish waste, and he can make electricity forever.”
Okay, so maybe that’s not exactly how the old saying goes. But researchers at Jadavpur University in Koltata, India, may be making this new version a reality. They have published a paper in Applied Physics Letters describing their work on using fish scales as a means of harvesting energy. According to the paper, it is widely known that single collagen nanofibers have piezoelectric properties. This means that they can take the energy from bending or impact and convert it into electricity (or vice versa). The common propane grill igniter uses this principle; a blow to a piezoelectric crystal creates an electrical spark without the need for batteries.
The key to the new discovery is that fish scales have naturally aligned collagen nanofibers arranged in a hierarchy. They were able to create a piezoelectric material using fish scales, laminated with electrodes on each side. The result was a device that is effective at harvesting energy from a variety of sources, including body movements, sound vibrations, and even airflow. Pressing the material repeatedly with a finger generates enough power to light 50 LEDs.
The result is a simple, biodegradable energy harvesting technology that can be single production step. The researchers envision all sorts of potential applications, from wearable devices to self-powered implants.