Nanogenerator uses good vibrations to power IoT networks

Tiny nanogenerators based on a new piezoelectric material can convert mechanical vibrations into electricity that could power Internet of Things (IoT) devices.

The compact and reportedly low-cost generating systems could power sensors in everything from pacemakers to spacecraft, according to the developers at the University of Waterloo and the University of Toronto in Canada.

The nanogenerators could reduce reliance on non-renewable power sources, said Asif Khan, a Waterloo researcher and co-author of a new study on the project. “We need these energy-generating materials more critically at this moment than at any other time in history.”

The system Khan and his colleagues developed is based on the piezoelectric effect, which generates an electrical current when pressure is applied to particular materials.

Until now, conventional piezoelectric materials used in commercial devices have had limited capacity for generating electricity, the researchers said. They also often use lead, which can be detrimental to the environment and human health.

The team set out to provide a solution by first growing a large single crystal of a molecular metal-halide compound called edabco copper chloride, using the Jahn-Teller effect, a well-known 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,” Khan said.

According to the study, published in Nature Communications, a composite film with the piezoelectric material has a peak power density of 43 µW/cm² (microwatts per square centimetre) at 50 kPa (kilopascal) of pressure, “the highest value reported for mechanical energy harvesters based on heavy-metal-free molecular piezoelectric.”

The researchers said the nanogenerators, which are 2.5cm² and about the thickness of a business card, could be used in “countless situations”.

“It has the potential to power sensors in a vast array of electronic devices, including billions needed for the IoT – the burgeoning global network of objects embedded with sensors and software that connect and exchange data with other devices,” an announcement said.

In future, an aircraft’s vibrations could power its sensory monitoring systems via the nanogenerators, or a person’s heartbeat could keep their battery-free pacemaker running, according to Waterloo researcher Dr. Dayan Ban. “Our new material has shown record-breaking performance. It represents a new path forward in this field.”