Imagine if you could transform carbon dioxide into batteries. Scientists may have managed just that; they've worked out a way to make electric vehicles that are carbon negative by using atmospheric carbon dioxide to operate.

The new ability lies in creating batteries with carbon material recovered from the atmosphere. But how exactly did scientists manage this feat?

The researchers adapted a solar-powered process that converts carbon dioxide into carbon so that it produces carbon nanotubes and demonstrated that the nanotubes can be incorporated into both lithium-ion batteries, like those used in electric vehicles and electronic devices, and low-cost sodium-ion batteries under development for large-scale applications. It builds upon a solar thermal electrochemical process (STEP) that can create carbon nanofibers from ambient carbon. STEP uses solar energy to provide both electrical and thermal energy necessary to break down carbon dioxide into carbon and oxygen.

In lithium-ion batteries, the nanotubes replace the carbon anode used in commercial batteries. In this latest demonstration, the researchers showed that carbon nanotubes gave a small boost to the performance, which was amplified when the battery was charged quickly. In sodium-ion batteries, the researchers found that small defects in the carbon can unlock stable storage performance over 3.5 times above that of sodium-ion batteries with graphite electrodes.

"This approach not only produces better batteries but it also establishes a value for carbon dioxide recovered from the atmosphere that is associated with the end-user battery cost unlike most efforts to reuse CO2 that are aimed at low-valued fuels, like methanol, that cannot justify the cost required to produce them," said Cary Pint, assistant professor of Mechanical Engineering at Vanderbilt University.

In theory, this new technique could transform the greenhouse gas carbon dioxide into valuable products. This could help with current climate change.

"Imagine a world where every new electric vehicle or grid-scale battery installation would not only enable us to overcome the environmental sins of our past, but also provide a step toward a sustainable future for our children," said Pint. "Our efforts have shown a path to achieve such a future.

The findings reveal a bit more about new strategies to both help reduce the amount of carbon dioxide already in the atmosphere, and also create more sustainable transportation for the future.