Eric Wolfe loads coal char pellets into a lab reactor that will turn the powdery material into graphite for battery anodes. Credit: ORNL, U.S. Dept. of Energy
Coal-to-graphite innovation turns waste materials from coal into tomorrow’s batteries, creating jobs and strengthening U.S. energy security.
Why it matters:
Graphite is essential for vehicle batteries and grid energy storage, yet domestic supplies are limited, making the U.S. dependent on imports. Meanwhile, coal waste poses an environmental challenge rather than functioning as an economic resource.
Real-world impact:
The electrochemical coal-to-graphite technology developed by Oak Ridge National Laboratory provides an economically viable path for U.S.-based graphite production while creating value from a waste stream. Industry partner Ramaco Carbon plans to commercialize the process, potentially revitalizing coal-mining regions and creating new skilled manufacturing jobs. An ORNL techno-economic analysis confirms the process can be scaled up profitably and produce graphite more affordably than the conventional graphite production process.
The benefits:
- Converts coal waste, such as the type left behind at closed mines, into high-quality graphite.
- Reduces dependency on foreign critical materials.
- Reduces projected production costs compared with conventional methods.
- Converts at lower temperatures, significantly reducing energy consumption compared to conventional methods.
- Supports environmental remediation and economic revitalization of former coal communities.
The innovation:
Using pitches — carbon-rich, tar-like byproducts — coal, and waste coal supplied by the University of Kentucky Center for Applied Energy Research, ORNL researchers developed an electrochemical process that efficiently transforms several different forms of coal-derived waste into graphite suitable for anodes, which are the negative electrodes of the lithium-ion batteries that power consumer electronics, cars, and grid energy storage systems. Unlike conventional methods, ORNL’s technique requires significantly less heat and processing time, using all the source materials while producing zero waste.
How it works:
- Coal is heated without oxygen in a process called pyrolysis, creating coal char and coal liquids.
- Coal liquids are further refined in an ORNL-developed application of aerosol spray-drying to create spherical particles.
- Both types of materials are then processed in an electrochemical reactor at relatively low temperatures (1,500 degrees Fahrenheit), transforming them into high-quality graphite.
- The graphite is integrated into battery anodes and tested extensively. Steps in the conversion process are refined to improve the resulting battery materials, so it performs comparably to commercial battery-grade graphite.
Backed by science:
The project was supported by the DOE’s Fossil Energy and Carbon Management Program.
- Research conducted at ORNL involved multidisciplinary collaboration among chemists, engineers, and materials scientists in the Energy Science and Technology and Physical Sciences directorates and experts in the Computing and Computational Sciences Directorate. Advances built upon earlier PSD development of benchtop electrochemical processes for converting coal to graphite. Laboratories across campus were involved in developing and scale-up of pyrolysis and molten salt reactors as well as creating and cycling coin cell batteries made with the material to test performance.
- Process optimization and validation occurred through advanced computational modeling, electron microscopy and computed tomography scanning, neutron scattering, and battery testing.
Deep dive:
Read more about ORNL’s coal-to-graphite research and explore opportunities for collaboration and commercialization.
The big picture:
ORNL’s coal-to-graphite technology provides value streams for coal waste in the energy economy, enhancing U.S. energy security and economic resilience.