MXene-Enhanced Fabric Supercapacitor Proves Suitable for Powering Real-World Arduino-Based Wearables

A team of researchers from Drexel University and Accenture Labs has come up with a flexible "patch" that could help power future wearables — turning MXene-enhanced textiles into supercapacitors.

"This is a significant development for wearable technology," claims Yury Gogotsi, PhD and professor at Drexel's College of Engineering, of the study he co-authored revealing the breakthrough. "To fully integrate technology into fabric, we must also be able to seamlessly integrate its power source — our invention shows the path forward for textile energy storage devices."

The team's work built atop earlier efforts to "functionalize" fabrics using MXene, a family of two-dimensional inorganic compounds first described in 2011, which focused on their durability and electrical conductivity. This time, though, the researchers were looking to see if MXene-enhanced fabrics could be turned into energy storage systems with a high enough energy density to power real-world electronics — specifically two off-the-shelf Arduino microcontrollers, an Arduino Pro Mini 3.3V and an Arduino Uno, connected to a temperature sensor and radio.

"While there are many materials out there that can be integrated into textiles, MXene has a distinct advantage over other materials because of its natural conductivity and ability to disperse in water as a stable colloidal solution," explains co-author Tetiana Hryhorchuk. "This means textiles can easily be coated with MXene without using chemical additives — and additional production steps — to get the MXene to adhere to the fabric. As a result, our supercapacitor showed a high energy density and enabled functional applications such as powering programmable electronics, which is needed for implementing textile-based energy storage into the real-life applications."

The team's design takes the form of a supercapacitor "patch," built to maximize energy density and thus minimize the use of active materials so as to keep costs down and avoid making the resulting clothing uncomfortable to wear. The production process is simple: Dipping woven cotton into an MXene solution, then layering on a lithium-chloride electrolyte. Sandwiching two layers together creates a cell, and stacking five together proved suitable to driving the Arduino — offering a power output of up to 6V.

"We came to the optimized configuration of a dip-coated, five-cell stack with an area of 25 square centimeters [around 3.9 square inches] to produce the electrical loading necessary to power programmable devices," says co-author Alex Inman. "We also vacuum-sealed the cells to prevent degradation in performance. This packaging approach could be applicable to commercial products."

The team's work has been published in the Journal of Materials Chemistry A under closed-access terms.