Good vibrations: device turns vibrations into electricity

An international team of researchers has engineered an energy-generating device by combining piezoelectric composites with carbon fibre-reinforced polymer (CFRP), a commonly used material that is both light and strong. The device transforms vibrations from the surrounding environment into electricity, providing an efficient means for self-powered sensors. The research findings were published in the journal Nano Energy.

Energy harvesting involves converting energy from the environment into usable electrical energy and is crucial for ensuring a sustainable future. Fumio Narita, co-author of the study and professor at Tohoku University, said everyday items such as fridges and street lamps are connected to the internet as part of the Internet of Things (IoT), and many of them are equipped with sensors that collect data. “But these IoT devices need power to function, which is challenging if they are in remote places, or if there are lots of them,” Narita said.

The sun’s rays, heat and vibration can all generate electrical power. Vibrational energy can be utilised due to piezoelectric materials’ ability to generate electricity when physically stressed. Meanwhile, CFRP lends itself to applications in the aerospace and automotive industries, sports equipment and medical equipment because of its durability and lightness.

“We pondered whether a piezoelectric vibration energy harvester (PVEH), harnessing the robustness of CFRP together with a piezoelectric composite, could be a more efficient and durable means of harvesting energy,” Narita said.

The researchers fabricated the device using a combination of CFRP and potassium sodium niobate (KNN) nanoparticles mixed with epoxy resin. The CFRP served as both an electrode and a reinforcement substrate. Tests and simulations of the so-called C-PVEH device revealed that it could maintain high performance even after being bent more than 100,000 times. It proved capable of storing the generated electricity and powering LED lights. It also outperformed other KNN-based polymer composites in terms of energy output density. The C-PVEH is forecast to help propel the development of self-powered IoT sensors, leading to more energy-efficient IoT devices.

“As well as the societal benefits of our C-PVEH device, we are thrilled with the contributions we have made to the field of energy harvesting and sensor technology. The blend of excellent energy output density and high resilience can guide future research into other composite materials for diverse applications,” Narita said.

Image credit: iStock.com/KanawatTH