Need more energy storage? Just press & # 39; print & # 39;

Researchers from Drexel University and Trinity College in Ireland have created an ink jet printer ink from a highly conductive two-dimensional material type called MXene. Recent discoveries, published in Nature Communications, suggest that the ink can be used to print flexible energy storage components, such as supercapacitors, regardless of their size or shape.

Conductive inks have been in existence for almost 10 years and represent a multi-million dollar market that is expected to grow rapidly over the next decade. It is already used to fabricate radio frequency identification tags used in highway toll transponders, printed circuit boards in portable electronic devices, as well as the lines of the car's window as "wireless". integrated radio antennas and to facilitate defrosting. But for the technology to be used more widely, conductive inks must become more conductive and more easily applicable to various surfaces.

Yury Gogotsi, Ph.D., Distinguished Professor and Bach Professor at Drexel College of Engineering, Department of Materials Science and Engineering, who studies the applications of new materials in technology, suggests Ink created by the Institute of Nanomaterials at Drexel constitutes a significant advance on both fronts.

"Until now, conductive inks have had limited success, both in fine-resolution printing and in high-load storage devices," Gogotsi said. "But our results show that MXene's fully printed micro-supercapacitors, manufactured with an advanced inkjet printer, are an order of magnitude greater than the existing energy storage devices made from other conductive inks. "

While researchers are constantly looking for ways to make inks from new, more conductive materials, such as silver nanoparticles, graphene and gallium, the challenge remains to seamlessly integrate them into manufacturing processes. . According to Babak Anasori, Ph.D., assistant professor in the Department of Materials Science and Engineering at Drexel and co-author of the MXene Ink Research, most of these inks can not be used in a single step .

"For most other nano-inks, an additive is needed to keep the particles together and allow high quality printing.For this reason, after printing, an extra step is needed – usually a heat or chemical treatment – to eliminate this additive, "Anasori said. "For MXene printing, we only use MXene in water or MXene in an organic solution to make the ink. This means that it can dry without any extra steps."

MXenes are a type of two-dimensional carbon-based laminates, created at Drexel in 2011, that have the unique ability to mix with liquids, such as water and other organic solvents, while maintaining their conductive properties . For this reason, Drexel researchers have produced and tested it in various forms, from conductive clay to electromagnetic interference coating, to an almost invisible wireless antenna.

Adjusting the concentration to create ink for use in a commercial printer was a matter of time and iteration. The concentration of solvent and MXene in the ink can be adjusted to suit different types of printers.

"If we really want to take advantage of any large-scale technology and prepare it for public use, it has to be very simple and it must be done in one step," said Anasori. "There is an inkjet printer in almost every home, so we knew that if we could make the right ink, it would be possible for anyone to make future electronics."

As part of this study, the Drexel team, in collaboration with Trinity College researchers, experts in printing, tested MXene ink in a series of prints including a simple circuit, a supercapacitor and text, substrates ranging from paper to plastic to glass. In doing so, they discovered that they could print lines of constant thickness and that the ink's ability to pass an electric current varied with its thickness, two important factors in the manufacture of components. e. And prints have retained their superior electrical conductivity, which is the highest of all carbon-based conductive inks, including carbon nanotubes and graphene.

All of this is a very versatile product for making tiny components that perform important but often overlooked functions in our electronic devices, such as maintaining power when the battery dies, preventing damaging power surges, or speeding up the charging process. Providing a more efficient material and a new way of building, could not only improve our current devices, but also create new technologies.

"Compared to conventional manufacturing protocols, the techniques of direct ink printing, such as ink jet printing and extrusion printing, allow the creation of of digital patterns and additives, customization, reduction of material losses, scalability and fast production, "said Anasori. "Now that we have produced an MXene ink that can be applied via this technique, we envision a world of new opportunities for use."