Using mechanical vibrations to power IoT networks

Engineers have created a new material that converts simple mechanical vibrations into electricity to power sensors in everything from pacemakers to spacecraft. The product of a decade of work by researchers at the University of Waterloo and the University of Toronto, the novel generating system is compact, reliable, low-cost and very green. Asif Khan, a Waterloo researcher and co-author of a new study on the project, said the material will have a significant social and economic impact by reducing reliance on non-renewable power sources. “We need these energy-generating materials more critically at this moment than at any other time in history,” Khan said.

The new system the researchers developed is based on the piezoelectric effect, which generates an electrical current by applying pressure — mechanical vibrations are one example — to an appropriate substance. The effect was discovered in 1880 and since then, a limited number of piezoelectric materials, such as quartz and Rochelle salts, have been used in technologies ranging from sonar and ultrasonic imaging to microwave devices. The problem is that until now, traditional piezoelectric materials used in commercial devices have had limited capacity for generating electricity. They also often use lead, which Khan describes as “detrimental to the environment and human health”.

The researchers grew a large single crystal of a molecular metal-halide compound called edabco copper chloride using the Jahn-Teller effect, a chemistry concept related to spontaneous geometrical distortion of a crystal field. The highly piezoelectric material was then used to fabricate nanogenerators with a record power density that can harvest tiny mechanical vibrations in any dynamic circumstances, from human motion to automotive vehicles, in a process requiring neither lead nor non-renewable energy.

The nanogenerator measures 2.5 cm² and is about the thickness of a business card, and could be conveniently used in countless situations. It also has the potential to power sensors in a range of electronic devices, including billions needed for the Internet of Things. Dr Dayan Ban, a researcher at the Waterloo Institute for Nanotechnology, said that in future, an aircraft’s vibrations could power its sensory monitoring systems, or a person’s heartbeat could keep their battery-free pacemaker running.

“Our new material has shown record-breaking performance. It represents a new path forward in this field,” Ban said.

The research findings were published in the journal Nature Communications.

Image credit: iStock.com/Andrey Suslov