Scientists turn carbon dioxide waste into graphite to opening new path beyond mining

The breakthrough observations solved a long-standing mystery about how the reaction works at the molecular level

A breakthrough by researchers at the US Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), UC Berkeley, and Estonia’s National Institute of Chemical Physics and Biophysics could reshape how one of the world’s most important battery materials is produced.

Graphite — the carbon found in everyday pencils — is also a critical ingredient in batteries, smartphones, laptops, and industrial power systems. Today, nearly all graphite used in these technologies comes from mining and processing, with the United States relying heavily on imports.

Now, scientists have demonstrated a new approach: converting carbon waste captured from the air into graphite, creating a potential alternative to traditional mining. The findings, published recently in Nature Communications, could help build a more resilient domestic supply of this critical mineral.

The research team developed a custom microscope system that allowed them to observe molten-salt electrolysis in action — a process that uses electricity and extremely hot liquid salts to transform carbon dioxide into solid carbon. For the first time, scientists captured the reaction in real time inside a harsh 500-degree-Celsius molten salt environment while the chemical process was underway.

The breakthrough observations solved a long-standing mystery about how the reaction works at the molecular level. Researchers discovered that the transformation happens through an unexpected two-step process and found that the core chemistry remains consistent even when different electrode materials and molten salts are used.

That discovery could give scientists greater control over the final carbon structure produced, potentially allowing them to engineer materials specifically for high-value applications — including battery-grade graphite.

“This is a major win in a larger effort of synthesizing critical materials and battery materials using molten salts,” said Mike Whittaker, a Berkeley Lab scientist who worked on the project. “If you could run this process at low temperatures with really cheap salts, you could have it in a lot of places, and you could generate enough graphite that you could feed into battery supply chains.”

Beyond graphite production, the research also introduces a powerful new way to study chemical reactions inside molten salts — environments that have traditionally been difficult to examine because of their extreme conditions.

Scientists will now focus on identifying the ideal combinations of molten salts, electrode materials, temperatures, and electrical voltages needed to produce graphite and other advanced carbon materials. The team must also scale up the technology to determine whether it can deliver industrial quantities of graphite.

The project was supported through the Minerals for Energy Storage Synthesis (MINES) program, funded by the Department of Energy’s Basic Energy Sciences program.