A new material is producible like a plastic, but conducts electricity in a manner similar to metal. The material thus goes against the rules on conductivity that we know. Conductive materials play an important role in electrical devices. Think of a smartphone or laptop, but also solar panels or cars.
The material was discovered by researchers at the University of Chicago. They share their findings in the scientific journal Nature. Despite the fact that the material's molecules are disordered, it can conduct electricity very well. The researchers foresee great opportunities with the material. "If you want to invent something revolutionary, the process often starts with the discovery of a completely new material," the university said.
'New class of materials possible'
"Basically, this paves the way for a whole new class of materials that conduct electricity, can be easily formed and are very robust in everyday conditions," explains John Anderson, a chemistry professor at the University of Chicago and lead author of the study. Jiaze Xie, who graduated in 2022 and is now affiliated with US Princeton University, added: "In essence, this suggests new possibilities for an extremely important technological group of materials."
Researchers succeeded in manufacturing conductive material from organic materials 50 years ago. In doing so, they deployed a chemical process known as 'doping'. In this process, researchers 'sprinkle' the material with other atoms or electrons. The process offers significant advantages. For instance, organic materials are more flexible and easier to process than traditional metals. However, they also have their limitations. For instance, the materials are unstable. They lose their conductivity when exposed to moisture or high temperatures.
Straight rows of atoms or molecules
Anderson and Xie's team points out that both this conductive organic material and traditional metal conductors share an important feature. Both consist of straight, closely packed rows of atoms or molecules. In practice, this means that electrons can easily flow through the material. Until now, it has been assumed that these straight, ordered rows are a hard requirement for conducting electricity.
However, this turns out not to be the case. The team started experiments with various materials several years ago. In these, they rain nickel atoms together with carbon and sulphate atoms in a chain. This material turns out to conduct electricity very easily and powerfully. The material is also very stable. "We heated it, cooled it, exposed it to air and humidity, and even dripped acid and alkali on it, and nothing happened," says Xie.
'There is no solid theory that explains this'
The discovery is striking as no clear theory is available to explain the development. The disordered structure of the material is particularly striking. Anderson: "There is no solid theory that explains it."
Researchers' theory is that the material forms layers, similar to the layers in a lasagne. Even if these layers rotate and no longer form a neat stack, electrons can move through the material both horizontally and vertically. The only condition is that layers touch each other. The resulting material offers very extensive possibilities; Anderson compares the material to "conductive Play-Doh".
New processing possibilities
Attractions of the discovered conductive material include new possibilities for processing the material. For instance, manufacturers melt metals to give them the right shape for use in a chip or device. This comes with limitations; for example, other components of the device must be able to tolerate the heat required to process the metals.
The new material does not have this limitation; processing takes place at room temperature. The researchers also expect the material to overcome limitations that engineers have previously encountered when developing new technologies. Currently, the team is investigating other forms in which the material can be processed. These include 2D, 3D and porous materials.
More information is available in Nature.
Author: Wouter Hoeffnagel
Photo: Gerd Altmann via Pixabay
