As America’s energy landscape evolves, NETL is advancing emerging technologies that offer new economic opportunities for the nation’s most abundant domestic resource — coal. Converting coal to high-value carbon nanomaterials has the potential to reduce manufacturing costs and energy consumption while improving the performance of electronics, batteries, solar cells, cements, plastics and other in-demand consumer products.

Carbon nanomaterials are tiny, carbon-based materials with unique properties that enhance the mechanical strength, optical properties, corrosion resistance, and thermal and electrical conductivity of materials. Traditionally derived from petroleum or graphite feedstocks, their use in commercial products has been limited largely due to high manufacturing costs and finite supplies. As an affordable alternative, NETL and its partners are developing simple, scalable methods to produce carbon nanomaterials from coal and coal byproducts.

The Lab’s most notable success to date is a patent-pending method for making graphene quantum dots — small fluorescent nanoparticles with sheet-like structures that are one atom thick and a few hundred atoms in diameter. Coal naturally contains graphite-like carbon structures that make it ideal for producing graphene-type nanomaterials, which can be used in composite plastics, batteries, water filtration systems and 3D printing materials. Researchers have successfully processed anthracite, bituminous and sub-bituminous coal samples from regional partners in Wyoming, Kentucky, Virginia and Pennsylvania to manufacture graphene quantum dots suspended in water. These nanomaterials have been incorporated into a common engineering plastic to impart unique optical properties, and NETL’s academic and commercial collaborators are evaluating samples for use in other applications, including computer memory devices and water- or stain-resistant coatings.

By capitalizing on coal’s natural building-block molecules, NETL’s method reduces the costs and technical challenges associated with producing carbon nanomaterials. Using one of the Lab’s processing methods, a penny’s worth of coal can be converted to 1 liter of graphene quantum dots suspended in water — worth about $50,000 — in just a few hours. A ton of coal, valued at $30-$60, could produce nanomaterials worth $300,000-$20 million per ton. One of NETL’s methods also co-produces valuable rare earth elements and distilled crude oil liquid, which offer opportunities for additional revenue streams in existing markets.

NETL has identified other processing methods that produce carbon nanomaterials with different functional groups to improve their compatibility/solubility in common polymers and solvents. Preliminary testing incorporated these carbon nanomaterials into wellbore cements and engineering plastics.

“Our work to develop carbon nanomaterials supports the Lab’s COAL MAT initiative, which is a coordinated research and technology development effort between national laboratories, universities and industry stakeholders that focuses on developing high-value products from coal feedstocks and evaluating how these products impact coal and manufacturing markets,” said Christopher Matranga, a researcher on NETL’s Functional Materials Team who serves as COAL MAT’s technical director.

The COAL MAT initiative supports NETL’s broader efforts to develop technological solutions for America’s energy challenges by making effective use of the nation’s vast fossil fuel reserves. Click here to learn more about the Lab’s Coal Beneficiation work.