Carbon nanotube design boosts thermoelectric output

Researchers from the Queensland University of Technology (QUT) have overcome a challenge that could open the door to more powerful wearable electronics and new ways to turn wasted heat into electricity. The researchers have developed a new molecular strategy that prevents carbon nanotubes — flexible and conductive microscopic rods that have shown promise for wearable technologies but can be difficult to control — from clumping together and losing performance.

The research findings have provided a new benchmark for materials that convert heat directly into electricity. Lead author and QUT PhD researcher Shanshan Zhou said the work established a new way of tackling one of the biggest challenges facing carbon nanotubes.

“Instead of trying to improve existing approaches, we came up with a new way to stop carbon nanotubes sticking together, which has been a major challenge for researchers for years. Because the approach is so flexible, it could be used to create a new generation of higher-performing materials for harvesting energy from heat,” Zhou said.

Professor Zhi-Gang Chen, Director of the ARC Research Hub in Zero-Emission Power Generation for Carbon Neutrality, said carbon nanotubes had enormous potential, but one persistent problem had stood in the way.

“For many years, researchers have recognised that carbon nanotubes are excellent candidates for wearable thermoelectric devices because they are lightweight, flexible and electrically conductive. However, their tendency to aggregate has severely limited their performance. Our new molecular design fundamentally changes how carbon nanotubes interact with each other. Instead of allowing them to clump together, we use specially designed molecules to keep the nanotubes apart without affecting their ability to carry electricity,” Chen said.

The researchers demonstrated the material’s real-world promise in a flexible device that generated electricity from body heat and remained durable after extensive bending and folding tests. Chen said the technology could eventually enable battery-free wearable devices.

“Imagine health monitoring sensors, smart textiles or wearable electronics that continuously harvest energy from your own body heat instead of relying on conventional batteries,” Chen said.

The researchers believe the technology could also be applied to waste heat recovery, flexible sensors, the Internet of Things and next-generation sustainable electronics.

The research findings have been published in Angewandte Chemie International Edition.

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