Laser printing produces waterproof energy-storing e-textiles in minutes
The next generation of waterproof smart fabrics will be printed with conductive graphene elements using a combo of CO2 and ultrafast lasers.
Scientists from RMIT University (Melbourne, Australia) have developed a cost-efficient and scalable laser-printing method for rapidly fabricating textiles that are embedded with energy-storage devices. In three minutes, the method can produce a 10 x 10 cm smart-textile patch that is waterproof, stretchable, and readily integrated with energy-harvesting technologies.1
The technology enables graphene supercapacitors (energy-storage devices) to be laser-printed directly onto textiles such as nylon. In a proof of concept, the researchers connected a laser-printed supercapacitor with a photovoltaic cell to produce an efficient, washable, self-powering smart fabric that they say overcomes the key drawbacks of existing e-textile energy-storage technologies.
The growing smart-fabrics industry has applications in wearable devices for the consumer, health care and defense sectors, including monitoring vital signs of patients, tracking the location and health status of soldiers in the field, and monitoring pilots and drivers for fatigue.
“Current approaches to smart-textile energy storage, like stitching batteries into garments or using e-fibers, can be cumbersome and heavy and can also have capacity issues,” says Litty Thekkakara, a researcher in RMIT’s School of Science. “These electronic components can also suffer short-circuits and mechanical failure when they come into contact with sweat or with moisture from the environment. Our graphene-based supercapacitor is not only fully washable, it can store the energy needed to power an intelligent garment, and it can be made in minutes at large scale."
The research analyzed the performance of the proof-of-concept smart textile across a range of mechanical, temperature, and washability tests and found it remained stable and efficient.
In the process, an elastomer is coated onto one side of nylon fabric while a graphene oxide and binder solution is panted on the other and dried. A combination of a continuous-wave (CW) CO2 laser and a femtosecond laser was used to pattern the fabric; the CO2 laser provides photothermal reduction and the ultrafast laser provides a combination of photothermal and photochemical reduction. The combination is a single-step optical lithographic fabrication method leading to conductive graphene films on the fabric.
Min Gu, a researcher at RMIT and also at the University of Shanghai for Science and Technology, says the technology could enable real-time storage of renewable energy for e-textiles. “It also opens the possibility for faster roll-to-roll fabrication, with the use of advanced laser printing based on multifocal fabrication and machine learning techniques,” Gu says.
The researchers have applied for a patent for the new technology, which was developed with support from RMIT Seed Fund and Design Hub project grants.
1. Litty V. Thekkekara and Min Gu , Nature Scientific Reports (2019); https://doi.org/10.1038/s41598-019-48320-z