NETL researchers who asked the question — “How can we use coal without burning it and generating greenhouse gas?” — have been awarded a U.S. patent for an invention that transforms coal into a game-changing material to manufacture valuable products and generate jobs in coal communities as the nation transitions to clean energy.

The recently patented NETL invention, 19N-01.NP1USPN 11,535,518, Production of Graphene-Structured Products from Coal Using Thermal Molten Salt Process, is now available for licensing. This low-cost NETL process uses domestically sourced coal and coal wastes as the feedstock to produce carbon nanosheets that can be instrumental to manufacture safer, fuel-efficient vehicles, durable roads and bridges and much more while finding new uses for coal resources.

Carbon nanosheets are several atomic layers of carbon thick and can be used to improve the strength of composite materials and the performance of battery electrodes. Despite these properties, carbon nanosheets have not been widely used in consumer products due to challenges in producing affordable quantities of the material.

NETL’s patented process resolves that issue by eliminating the need for expensive graphite feedstocks. Instead, the NETL process relies on inexpensive components — lignite, bituminous and anthracite ranks of coal and potassium chloride or sodium chloride (salts). These materials are then heated in a simple manufacturing process to produce a graphene-like material that is significantly less expensive and of superior quality for use in a wide range of real-world applications.

“One of the primary applications involves using this carbon product to manufacture improved vehicle parts such as lighter and stronger bumpers, door panels and other components, which increases safety, saves fuel and extends the number of miles an electric vehicle can travel on a single charge,” said NETL’s Fan Shi, the project’s lead inventor.

In addition, NETL is evaluating the use of the material as an additive for improving the mechanical strength and corrosion resistance of cement and concrete composites for construction. “This development is critical to building the better highways, bridges and basic infrastructure the nation needs,” Shi said.

NETL has been on the cutting edge to advance the development of carbon nanosheets and other carbon materials made from U.S. coal resources. In 2020, NETL’s carbon nanosheet process received a prestigious R&D 100 award for being among the 100 most technologically significant innovations introduced into the marketplace in the previous year.

NETL is investigating commercial applications for its carbon material technologies through partnerships with industry and academia. For instance, NETL is collaborating with the University of Illinois Urbana-Champaign to develop atomically thin carbon materials for computer memory devices and other microelectronics. This research could dramatically increase the nation’s ability to produce computer chips at a time when the offshore nature of this industry has caused supply chain disruptions. 

“These NETL technologies can also create new markets for coal, which will also help revitalize coal communities as the United States transitions to a clean energy economy, and remediate environmental problems associated with past mining and energy production practices in those communities,” Shi said.

Developed by Shi and NETL colleagues McMahan Gray, Christopher Matranga and Tuo Ji, the new invention uses molten salt as both the catalyst and processing medium to convert the coal feedstock into a mixture of amorphous carbon and carbon nanosheets. After the mixture cools, the material is washed with hydrochloric acid and rinsed with deionized water. Byproducts can then be treated with other technologies, including NETL’s Multi-functional Sorbent Technology (MUST), to extract rare earth elements (REEs) and critical minerals.

The United States currently imports more than 80% of its REEs from offshore suppliers to produce clean energy technologies such as solar panels and wind turbines and indispensable products, including smartphones, computers and medical equipment. 

Email TTLicensing@netl.doe.gov to learn more about licensing opportunities and information about the invention Production of Graphene-Structured Products from Coal Using Thermal Molten Salt Process.

NETL is a U.S. Department of Energy national laboratory that drives innovation and delivers technological solutions for an environmentally sustainable and prosperous energy future. By leveraging its world-class talent and research facilities, NETL is ensuring affordable, abundant and reliable energy that drives a robust economy and national security, while developing technologies to manage carbon across the full life cycle, enabling environmental sustainability for all Americans.