R. Pandey, U.R. Gracida-Alvarez, R.K. Iyer, J.C. Kelly
Argonne National Laboratory,
United States
Keywords: synthetic graphite, life cycle analysis (LCA), lithium-ion battery (LIB), battery anode, U.S. graphite supply chain
Summary:
Approximately 95% of graphite used in U.S. vehicle battery anodes is imported, highlighting a significant opportunity for expanding domestic graphite production. Synthetic graphite can be produced from petroleum coke, which can be sourced from refineries within the U.S., thereby reducing the reliance on imported graphite (natural or synthetic). This feedstock substitution with domestic resources for battery applications could enhance energy independence, improve supply reliability, and support U.S. manufacturing competitiveness. Since synthetic graphite production is energy-intensive, it is critical to understand the likely environmental implications of its domestic production. We conduct a comprehensive cradle-to-gate life cycle analysis (LCA) of potential synthetic graphite anode battery material (BAM) production in the U.S. for lithium-ion batteries (LIBs) based on industrial-scale production data. The analysis focuses on three impacts: total life-cycle energy use, water consumption, and greenhouse gas (GHG) emissions. The baseline results show GHG emissions of 29.7 kg CO2-eq/kg BAM, total energy use of 580 MJ/kg BAM, and water consumption of 121 L/kg BAM. The graphitization step is a major process hotspot, contributing over 74% to all impacts due to high energy demand and crucible requirements. Across the entire synthetic graphite production processes, electricity is the largest contributor, followed by crucibles, which are used in graphite block production, and petroleum coke. Different sensitivity analysis scenarios are also conducted to understand the impact of process variations and identify areas for impact reduction. The results indicate that reducing crucible losses and reusing them, improving micronizing yield, and sourcing low-carbon electricity, such as nuclear energy, can significantly reduce GHG emissions of potential domestic graphite production (by ~70%). A complementary supply chain analysis identifies major U.S. graphite BAM sources and indicates that the U.S. has a competitive advantage in terms of lower environmental impact with domestic production compared to present-day imported sources.