Consider, for a moment, the electrical wire, a pervasive technology that’s extremely easy to forget. Spooled up inside our devices, wrapped around our walls, strung along our streets, millions of tons of thin metallic threads do the job of electrifying the world. But their work is benign, and so naturalistic that it does not really feel like technology at all. Wires move electrons simply because that is what metals do when a current is supplied to them: They conduct.
But there’s always room for improvement. Metals conduct electricity because they contain free electrons that aren’t tethered to any particular atoms. The more electrons that flow, and the faster they go, the better a metal conducts. So to improve that conductivity—crucial for preserving the energy produced at a power plant or stored within a battery—materials scientists are typically on the hunt for more perfect atomic arrangements. Their chief aim is purity—to remove any bits of foreign material or imperfections that break the flow. The more a hunk of gold is gold, the more a copper wire is copper, the better it will conduct. Anything else just gets in the way.
“If you want something really highly conductive, then you’ve just got to go pure,” says Keerti Kappagantula, a materials scientist at the Pacific Northwest National Lab. Which is why she considers her own research rather “wonky.” Her goal is to make metals more conductive by making them less pure. She’ll take a metal like aluminum and throw in additives like graphene or carbon nanotubes, producing an alloy. Do that in just the right way, Kappagantula has found, and the extra material can have a weird effect: It can push the metal past its theoretical limit of conductivity.
The point, in this case, is to create aluminum that can compete with copper in electrical devices—a metal that’s nearly twice as conductive, but also costs about twice as much. Aluminum has benefits: It’s much lighter than copper. And as the most abundant metal in the Earth’s crust—a thousand times more so than copper—it’s also cheaper and easier to dig up.
Copper, on the other hand, is getting harder to source as the world transitions to greener energy. Though long ubiquitous in wiring and motors, demand for it is surging. An electric vehicle uses about four times as much copper as a conventional car, and still more will be required for the electrical components for renewable power plants and the wires that connect them to the grid. Analysts at Wood Mackenzie, an energy-focused research firm, estimated that offshore wind farms will demand 5.5 megatons of the metal over 10 years, mostly for the massive system of cables within generators and for carrying the electrons the turbines produce to the shore. In recent years, the price of copper has spiked, and analysts project a growing shortfall of the metal. Goldman Sachs recently declared it “the new oil.”
Some companies are already swapping it out for aluminum where they can. In recent years, there has been a multibillion-dollar shift in the components of everything from air conditioners to car parts. High-voltage power lines already use aluminum wires, because they are both cheap and lightweight, which allows them to be strung over longer distances. That aluminum is typically in its most pure and highly conductive form.
