The team at Trinity College, Dublin, has developed key expertise in 3D printing energy components, including batteries, while researchers at Drexel have been working on MXene, which is similar to graphene as a carbon-based 2D material with ability to mix with liquids, like water and other organic solvents, while retaining their conductive properties. MXene was created at Drexel in 2011, and researchers there have produced and tested it in a variety of forms, from conductive clay to a coating for electromagnetic interference shielding to a near-invisible wireless antenna.
"So far only limited success has been achieved with conductive inks in both fine-resolution printing and high charge storage devices," said Prof Yury Gogotsi in Drexel University's College of Engineering, Department of Materials Science and Engineering. "But our findings show that all-MXene printed micro-supercapacitors, made with an advanced inkjet printer, are an order of magnitude greater than existing energy storage devices made from other conductive inks."
Eliminating the neeed for additives to enable the 3D printing has boosted the performance of the resulting supercapacitors.
"For most other nano inks, an additive is required to hold the particles together and allow for high-quality printing. Because of this, after printing, an additional step is required - usually a thermal or chemical treatment - to remove that additive," said Babak Anasori, a research assistant professor in Drexel's department of Materials Science and Engineering. "For MXene printing, we only use MXene in water or MXene in an organic solution to make the ink. This means it can dry without any additional steps. Adjusting the concentration to create ink for use in a commercial printer was a matter of time and iteration. The solvent and MXene concentration in the ink can be adjusted to suit different kinds of printers.