Dongguk University Develops Gel-Based Triboelectric Nanogenerators for Wearables

Researchers at Dongguk University in Seoul, South Korea, have developed a gel polymer-based triboelectric nanogenerator that generates electrical signals from body movement to power electronics like LEDs and functions as a self-powered touch panel for user identification. 

Triboelectric nanogenerators (TENGs) that convert mechanical energy, such as body movement to electrical energy offer a power solution for these devices without using batteries. Most TENGs used in wearable applications incorporate a triboelectric material attached to an electrode that conducts current. However, this does not provide flexibility so that devices can move with the human body.

This device is stretchable, semi-transparent, and durable, making it suitable for wearable sensor applications. It can stretch up to 375% of its original size and withstand rigorous mechanical deformations. 

The research team that developed this gel polymer electrode-based triboelectric nanogenerator (GPE-TENG) was led by Professor Jung Inn Sohn from Dongguk University-Seoul in the Republic of Korea. 

“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,” said Sohn.

To create the device, Sohn and his team poured a gel mixture of polyethylene oxide (PEO) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) into an ecoflex mold. 

The gel was evenly spread and 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.

When tapped or stretched, the device delivered 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.

This paper was published in Volume 499 of the Chemical Engineering Journal on November 1, 2024.