Engineers have developed a novel way to store energy: using a 3D printer to turn 2D materials into electrodes that can be used in energy storage devices such as supercapacitors.
The team of University of Manchester researchers used MXene, a clay-like substance with properties similar to graphene. Created by researchers at Drexel University, MXene is made up of carbon atoms and early transition metals such as titanium. The substance is hydrophilic, which means it can be turned into an ink for 3D printing—and once it dries it is an excellent electrical conductor. These properties make MXene much more suitable for energy storage uses than most other 2D clays, which are not as conductive.
The discovery of graphene—a substance a million times thinner than a human hair, but more conductive than copper and stronger and more flexible than steel—created an entirely new field of research into two-dimensional materials with a wide variety of properties. MXene is just one of a variety of graphene-inspired materials to have been created.
But integrating these 2D materials into usable structures and devices has been a significant challenge, limiting their usefulness in the real world. By turning the two-dimensional MXene into an ink for 3D printing, the researchers may have found one way of overcoming that challenge.
“We demonstrate that large MXene flakes, spanning a few atoms thick, and water can be independently used to formulate inks with very specific viscoelastic behaviour for printing,” said team leader Suelen Barg. “These inks can be directly 3D printed into freestanding architectures over 20 layers tall.”
The MXene electrodes have significant potential for use in supercapacitors—energy storage devices that can produce a lot of power while using very little energy, and which can charge faster and tolerate more recharges compared to conventional devices. Supercapacitors can store more power, and can weight significantly less than conventional energy storage devices—making them a valuable technology for electric cars, mobile phones and other electronic devices.
As the Manchester team has shown with its 3D printer, additive manufacturing could play a crucial role in unlocking the potential of MXene, graphene and other 2D materials. “Additive manufacturing offers one possible method of building customised, multi-materials energy devices, demonstrating the capability to capture MXene’s potential for usage in energy applications,” said members of the team. “We hope this research will open avenues to fully unlock the potential of MXene for use in this field.”
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