If you’ve ever returned from a run or a workout in a hurry to ditch your sweat-soaked clothes and jump in the shower, you’ve probably never considered that your pile of discarded clothes could be a potential source of renewable energy, one that could eliminate the need to charge your wearable devices.

At Deakin University’s Institute for Frontier Materials (IFM), researchers in the Future Fibres Group have been working on a design to power wearable devices using sweat, which could make plug-in chargers obsolete. But rather than extracting sweat that has already transferred to your clothes, it generates electricity straight from your skin.

Dr Ken Aldren Usman is one of the researchers at IFM working on the project. His vision is to redesign materials for a circular economy and create materials with “extraordinary functionality”.

Facilitating interconnected research is a core principle at IFM. Even the office seating plan is designed with collaboration in mind. One person might be working on batteries and the next on metals, promoting the exchange of ideas.

“The idea behind the IFM is to get people with lots of different areas of expertise collaborating,” Usman says. “From my point of view, it was really helpful to be able to ask somebody from another field to work with me.”

Among the researchers working on the wearables project are experts in nanogenerators (tiny devices that convert energy into electricity) and device fabrication. Usman’s expertise was in MXenes, innovative new materials that are a million times thinner than paper.

Usman wanted to build on his PhD research to understand how MXenes could be turned into a functional solid form (fibres). So he joined forces with his colleagues, Dr Hongli Su, who was developing wearable hydroelectric nanogenerators (also known as HENGs) as a part of his own PhD thesis, and Su’s supervisor, Dr Azadeh Nilghaz, who has experience in device fabrication. When the three came together the design possibilities expanded.

“When Hongli approached me, his problem was he wanted a material that would improve his device,” Usman says. “At that time, I had a material that had unique properties, but I didn’t know where to use it. So we were both in the perfect place at the perfect time.” The group focused on developing wearable HENGs, which harness energy from sweat evaporation and are part of the broader field of energy-harvesting technologies aimed at tapping renewable energy sources efficiently.

The IFM is based in Geelong, which has a long history of wool sales and exports, so it made sense to consider wool as a potential match for the MXenes.

“We all know wool shrinks,” Usman says. “But if you think of it another way, it means wool fabrics also could tolerate a huge amount of stretch. This is crucial for wearable electronics, especially for conductive fibres, as we need them to be robust and retain a certain level of conductivity.”

Reducing waste was also an important consideration. “Wool is also expensive. We thought any function we can add to wool off-cuts or discarded fibres would be of great value.”

The wool embedded with MXenes was successfully tested using a salt solution. Then it was time to confirm that it worked with human sweat. In the grand tradition of scientific breakthroughs, Hongli volunteered to test the product on himself.

“Su put on the prototype device and ran on a treadmill for six to 10 minutes,” Usman says. “The capacitor actually charged! So, we placed it into a small watch, and it was able to successfully power it.”

Usman believes their research has serious potential for wearable devices – and not just smartwatches. The implications for medical devices could be life changing. A device that never has to be charged can provide round-the-clock protection. It might also be the catalyst for changing the way we think about sweat. No longer something to be washed away, sweat might become a renewable source of power.

While an industry partner and a marketable product may be years away, that hasn’t stopped Usman and the research team from focusing on the bigger picture, and thinking of applications for the technology beyond something you can wear on your wrist.

“Imagine if you could eliminate the bulky power source on a spacesuit, and instead utilise the sweat from an astronaut’s body to power their suit,” Usman says. “I hope to see it 10 to 15 years from now.

“There’s still a long way to go. But, yeah, we’re dreaming big.”

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