When we think of energy, often large-scale grid storage or sleek, highly-efficient lithium ion batteries that power most of our electronics are the first things that come to mind. However, for applications such as biomedical or environmental monitoring devices, there could be an alternative way to harness energy without the use of pricy technology.
Researchers have discovered the through harnessing the energy crated by small motions, a small but unlimited power supply could be generated. With electrochemical principals as the backbone of the study, MIT researchers have developed a new way to harvest energy from natural motions and activates, including something as simple as walking.
The system is based on the slight bending of a sandwich of metal and polymer sheets.
This from MIT:
Most previously designed devices for harnessing small motions have been based on the triboelectric effect (essentially friction, like rubbing a balloon against a wool sweater) or piezoelectrics (crystals that produce a small voltage when bent or compressed). These work well for high-frequency sources of motion such as those produced by the vibrations of machinery. But for typical human-scale motions such as walking or exercising, such systems have limits.
“When you put in an impulse” to such traditional materials, “they respond very well, in microseconds. But this doesn’t match the timescale of most human activities,” says Ju Li, co-author of the paper. “Also, these devices have high electrical impedance and bending rigidity and can be quite expensive.”
The new technology works similarly to lithium ion batteries, allowing for flexibility to produce inexpensive energy at the large scale. Unlike a typical battery, this system takes mechanical energy and puts out electricity.
“It is not limited by the second law of thermodynamics,” Li says. “So in principle, [the efficiency] could be 100 percent.”