Imagine if you had the ability to transform carbon dioxide into a new, sustainable energy source for vehicles. Researchers at Vanderbilt University may have accomplished just that. 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.