Rice University researchers have created a tiny coaxial cable about a thousand times smaller than a human hair that has higher capacitance than previously reported microcapacitors. The three-layer, 100-nanometer-wide cable was described recently in Nature Communications. The cable was produced with techniques pioneered in the nascent graphene field and could be used to build next-generation energy-storage systems.

In a Rice University press release announcing the study, co-author Jun Lou, associate professor of mechanical engineering and materials science said, “We didn't expect to create this when we started. At the outset, we were just curious to see what would happen electrically and mechanically if we took small copper wires known as interconnects and covered them with a thin layer of carbon.”

The press release said the tiny coaxial cable is remarkably similar in makeup to the ones that carry cable television signals into millions of homes and offices. The heart of the cable is a solid copper wire surrounded by a thin sheath of insulating copper oxide. A third layer, another conductor, surrounds that. In the case of TV cables, the third layer is copper again, but in the nanocable it is a thin layer of carbon measuring just a few atoms thick. The coax nanocable is about 100 nanometers, or 100 billionths of a meter wide.