iot smart city

New material harvests subtle vibrations to power IoT devices

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Engineers have created a new material that converts subtle mechanical vibrations into electricity that could be used to power devices such as pacemakers, or even spacecraft.

Researchers at the University of Waterloo and the University of Toronto said the novel generating system is compact, reliable, low-cost and environmentally friendly.

“Our breakthrough will have a significant social and economic impact by reducing our reliance on non-renewable power sources,” said Waterloo researcher Asif Khan, co-author on the project. “We need these energy-generating materials more critically at this moment than at any other time in history.”

The system is based on the piezoelectric effect, which generates an electrical current by applying pressure, such as mechanical vibrations, 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 can be detrimental to the environment and human health.

The researchers started by 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.

A 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 is just 2.5cm square and about the thickness of a business card. It generates enough energy to power various IoT devices such as embedded sensors and software that connects and exchanges data with other devices.

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,” said Ban, a professor of electrical and computer engineering. “It represents a new path forward in this field.”

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