Scientists create new device to harvest human movement for sustainable energy

The principle, structural design, and application of unidirectional carbon fiber-reinforced flexible piezoelectric nanocomposite materials. Credit: Tohoku University

An international team of researchers has made a significant breakthrough in the field of motion sensors and sustainable energy.

They have developed a new, high-strength flexible device that can convert human motion into electricity.

This device is a fusion of piezoelectric composites and unidirectional carbon fiber (UDCF), a material known for its strength in a specific direction.

This exciting development was detailed in the journal Small.

The essence of this technology lies in its ability to turn the energy from our movements into electrical signals.

This process, known as motion detection, is gaining attention for its potential role in a sustainable future. Imagine wearing a device that can generate power just from your daily activities!

Fumio Narita, a co-author of the study and a professor at Tohoku University, highlights the significance of this innovation, especially in the era of the Internet of Things (IoT).

IoT has brought everyday items, from sports gear to personal protective equipment, online. These items often come equipped with sensors that collect data. The challenge has been to power these sensors efficiently and reliably, without compromising on the material’s durability and flexibility.

Piezoelectric materials, which generate electricity when stressed physically, are at the heart of this solution. Carbon fiber, renowned for its strength and lightweight nature, is already used in industries such as aerospace, automotive, sports equipment, and medical devices.

The research team explored the idea of combining carbon fiber with a piezoelectric composite to create a device that is not only flexible and durable but also capable of sensing.

Their creation, a composite of unidirectional carbon fiber fabric and potassium sodium niobate (KNN) nanoparticles mixed with epoxy resin, has proven to be a game-changer. The carbon fiber in this device serves both as an electrode and as a reinforcement that directs the strength of the material.

The UDCF/KNN-EP device, as it’s called, exceeded expectations in tests. It showed high performance even after being stretched over 1,000 times.

When compared to other flexible materials, this device can handle much higher loads, especially when pulled in the direction of the fiber. It also outperforms other piezoelectric polymers in energy output density when impacted or stretched perpendicular to the fiber direction.

The mechanical and piezoelectric properties of the UDCF/KNN-EP were thoroughly analyzed through multi-scale simulations in collaboration with Professor Uetsuji’s group at the Osaka Institute of Technology.

This invention is set to revolutionize the field of self-powered IoT sensors, paving the way for advanced, multifunctional IoT devices.

The potential applications are vast and varied. For instance, when integrated into sports equipment, the UDCF/KNN-EP was able to accurately detect the impact from catching a baseball and monitor a person’s step frequency.

Professor Narita and his team are enthusiastic about the future possibilities of their technology. By leveraging the strength of carbon fibers, they have enhanced the sustainability and reliability of battery-free sensors.

This development maintains the material’s directional stretchability and provides valuable insights for future research in motion detection.

Source: Tohoku University.