Environmentally Responsible Chemical Purification Method of Natural Graphite for Sustainable Battery Production ^†

The global transition to renewable energy is an immediate goal to ensure access to affordable, reliable, sustainable and modern energy for all, which is fully consistent with Sustainable Development Goal 7. Meanwhile, the global transition to renewable energy depends on secure and sustainable access to critical raw materials. Natural graphite is indispensable for lithium-ion batteries (LIBs), which underpin energy storage systems, electric vehicles, and other clean technologies. Ukraine possesses the largest natural graphite reserves in Europe, which creates a strategic opportunity to reduce its dependence on imports. However, natural graphite must be purified to a purity level of at least 99.95% to meet battery-grade specifications, requiring the removal of silicate and metal oxide contaminants. Conventional purification methods, particularly those based on hydrofluoric acid, are efficient but pose significant environmental and occupational hazards due to their toxicity and high fluoride emissions. Thermal purification, while capable of achieving ultra-high purity, demands temperatures exceeding 2500 °C, making the process energy-intensive and economically expensive. Within the Horizon Europe GR4FITE3 project, researchers at the Kyiv National University of Technology and Design (KNUTD) have developed a low-fluoride chemical purification method using a minimal and precisely controlled amount of ammonium fluoride combined with sulfuric acid and auxiliary additives. Unlike conventional hydrofluoric acid-based processes, ammonium fluoride is not used directly to dissolve impurities. Instead, it selectively disrupts the crystalline structure of mineral impurities, enabling sulfuric acid to efficiently leach out contaminants. This one-step treatment consistently achieves graphite purities between 99.97 and 99.99% without leaving residual fluorine on the graphite surface, significantly reducing chemical consumption and environmental risks. To assess industrial feasibility, KNUTD has designed a modular pilot purification line featuring closed-loop water treatment and emission control systems. This pilot purification line supports cost-effective graphite production. The KNUTD method offers a novel and safer pathway toward sustainable battery materials, crucial for advancing Europe’s renewable energy infrastructure and strategic autonomy.