The created the GPE-TENG by sandwiching a gel electrode between two triboelectric ecoflex layers. (Image Credit: Dongguk University-Seoul)
We're seeing a growing demand for wearables, like medical sensors, trackers, and smartwatches, and these require triboelectric generators (TENGs) to produce electricity. Many TENGs feature a triboelectric material fixed to an electrode to conduct current. Finding a flexible material that moves with human movement has proven challenging. Engineers from Dongguk University-Seoul fabricated a gel polymer electrode-based triboelectric nanogenerator (GPE-TENG). The device can be used for sensors thanks to its robust, stretchable, and semi-transparent qualities.
"We report an in-situ curing strategy to develop a stretchable, semi-transparent, and durable GPE-TENG through enhanced interfacial bonding between the ionic polymer gel and ecoflex layers," explains Prof. Sohn.
The team created the GPE-TENG by pouring a polyethylene oxide (PEO) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) gel mixture into an ecoflex mold. This gel is equally distributed before an additional ecoflex layer covers it. To provide electrical connectivity, the researchers attached a copper wire to the gel. Afterward, the team cured it for 12 hours @ 158°F to allow the gel to adhere to the ecoflex layers.
This process led to the creation of a flexible, durable, and semi-transparent generator with electrical signal production capabilities. It delivers 0.36 W/m² peak power at a load of 15 MΩ. During trials, the team stretched the device to 375% of its original size without causing damage. It also survived stretching, bending, twisting, and folding for two months without experiencing electrical performance loss or delamination.
Wearables with these GPE-TENGs could track joint activity for rehab. They could also be integrated into clothes, acting as a biometric system for wearers to unlock smart doors or lockers.
"This work could revolutionize wearable technology by developing sustainable and flexible electronic devices with promising applications in human health care, rehabilitation, security systems, and secure biometric authentication systems," says Prof. Sohn.
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