Batteries that eat carbon dioxide

Lithium-carbon dioxide batteries can store renewable energy while absorbing carbon. How do we move from theory to building, asks Nicole Kobie

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Carbon dioxide is a bit of a problem, what with changing the climate and all. But what if we had batteries that could not only trap this problematic gas, but also store renewable energy?

That is exactly what researchers at the University of Surrey are working to create: a lithium-carbon dioxide (Li-CO2) battery. If successful, such batteries could not only help suck carbon dioxide out of the air but also offer better solutions to power electric vehicles, the energy grid and even missions to Mars.

But don't breathe a sigh of relief just yet: not only are these designs merely batteries in gas-filled jars in a lab, and at least a decade off in the future in terms of commercial viability, they also come with plenty of caveats. The question is, how do we get from here to smartphones that inhale CO2 and exhale energy?

Building a better battery

Cars and laptops alike are powered by lithium-ion batteries, which move lithium ions back and forth to either power a device or recharge, using a lithium metal oxide such as lithium cobalt oxide as the cathode and a graphite as the anode.

While these work well enough to power gadgets around the world, this design comes with challenges, including costs, the use of conflict minerals, difficulty in recycling, and less charge capacity every time the battery is recharged. What's more, lithium-ion batteries have an annoying tendency to catch fire if damaged or overheated - you may remember Samsung having to recall the Galaxy Note 7 after it kept exploding back in 2016.