South Korean Team Develops Method To Power Wearables Via Body Movement

A research team from Dongguk University in Seoul, South Korea has developed a stretchable film that can generate electrical signals from body movement to power electronics like LEDs. According to the team, the device can stretch up to 375% of its original size and withstand wear and tear, making it suitable for wearable applications. The device is considered a triboelectric nanogenerator (TENG), a growing category of technology that aims to harness energy from the body’s regular movements to power wearables.

Most TENGs used in wearable applications incorporate a triboelectric material attached to an electrode that conducts current. However, one of the challenges has been finding flexible electrode materials that can move seamlessly with the human body.

To address these challenges, a research team led by Professor Jung Inn Sohn from Dongguk University-Seoul in the Republic of Korea developed a TENG made from a gel polymer. This device is stretchable, semi-transparent, and durable, making it suitable for wearable sensor applications. This paper was made available online on 11 Oct 2024 and was published in Volume 499 of the Chemical Engineering Journal on November 1st.

To fabricate the device, the researchers poured a gel mixture of polyethylene oxide (PEO) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) into an ecoflex mold. The gel is spread evenly and then covered with another ecoflex layer. A copper wire is attached to the gel for electrical connection, and the entire assembly is cured at 70°C for 12 hours, allowing the gel to bond strongly with the ecoflex layers.

The result is a durable, flexible, and semi-transparent device that generates electrical signals when tapped or stretched, delivering a peak power of 0.36 W/m² at a load of 15 MΩ. In tests, the device stretched up to 375% of its original size without damage and could withstand two months of bending, twisting, folding, and stretching without any signs of delamination or loss of electrical performance.

As wearable technology becomes a bigger part of our daily lives, the proposed GPE-TENG could enable wearable devices that track joint activity for rehabilitation purposes or act as a biometric system in clothing, allowing users to unlock smart doors or lockers. “This work could revolutionize wearable technology by developing sustainable and flexible electronic devices with promising applications in human healthcare, rehabilitation, security systems, and secure biometric authentication systems,” says Prof. Sohn.

See also: Research: Wrist-Worn Wearables To Grow By 8.7% In 2024