Fabricable material like a plastic but conducts electricity like a metal

Scientists have discovered how to make a material in which the molecular fragments are jumbled and disordered, but which can conduct electricity extremely well. This goes against all the rules we know about electrical conductivity.

The achievement is the work of Jiaze Xie’s team, from the University of Chicago in the United States.

Electrically conductive materials are absolutely essential for making any type of electrical device, be it an iPhone, a solar panel or a television. By far the oldest and largest group of conductors is that of metals, dominated by copper. Then, about 50 years ago, it was possible to create conductors made of organic materials, using a chemical treatment known as “doping”, which sprinkles different atoms or electrons throughout the material. This makes the materials more flexible and easier to process compared to traditional raw metals, but the problem is that they are not very stable; they can lose their conductivity if exposed to moisture or if the temperature gets too high.

In any case, both these organic conductors and the traditional metallic ones share a common characteristic: they are made up of rows of atoms or molecules that are straight and close together. This means that electrons can easily flow through the material, like cars on a highway. In fact, scientists used to think that a material had to have these neat, straight rows to conduct electricity effectively.

So Xie started experimenting with some materials discovered years ago but largely neglected by the electrical engineering industry. He placed nickel atoms like beads on a chain of molecular beads made of carbon and sulfur, and began testing.

To the astonishment of scientists, the material turned out to be able to conduct electricity easily and very efficiently. Also, it is very stable. “We heated it, cooled it, exposed it to air and moisture, and even dropped drops of acids and bases on it, and nothing happened,” says Xie. It is obvious that such a material is much more practical to use than more delicate materials. And in addition, the molecular structure of the material is disordered, despite which it conducts electricity.

Xie and other scientists set out to find out how the new material can conduct electricity. After tests, simulations and theoretical analysis, they believe that the material forms layers, and that the electrons can continue to move horizontally or vertically, as long as the pieces touch.

I work in a laboratory employed in the investigation of the new material. (Photo: John Zich/University of Chicago)

One of the most attractive features of the new material lies in its new processing options. For example, metals often need to be melted down to be shaped into a chip or other component or device. That introduces limitations to what can be done, since the other materials have to be able to withstand the heat needed to melt those metals.

In contrast, the new material does not have that restriction because it can be manufactured at room temperature.

Additionally, it can be used where the need for a device or device parts to withstand extreme levels of heat, acidity, alkalinity, or humidity has previously limited engineers’ options for developing new technology.

Xie and his colleagues expose the technical details of the new material in the academic journal Nature, under the title “Intrinsic glassy-metallic transport in an amorphous coordination polymer”. (Font: NCYT by Amazings)