Cradle-to-gate carbon footprints of battery-grade nickel and cobalt cathode materials

Nickel sulfate (NiSO 4 ) and cobalt sulfate (CoSO 4 ) are key cathode precursors for lithium nickel–cobalt–manganese (NCM) batteries; however, their production raises important sustainability concerns. Existing studies often overlook the diversity of upstream products, the role of Chinese refining activities, and the co-production of nickel and cobalt chemicals. This study integrates enterprise data from China's domestic refining sector with upstream processing for NiSO 4 and CoSO 4 production, providing a comprehensive evaluation of their carbon footprint (CF) characteristics across typical production routes. The results show that the average CFs of NiSO 4 and CoSO 4 are 5.60 and 5.15 tCO 2 -eq/t, respectively. Energy consumption accounts for the dominant share of emissions, while ore grade, production scale, and fuel type also exert significant influences. Hydrometallurgical routes result in a higher CF for NCM811 and NCM523 batteries than pyrometallurgical routes. This analysis highlights critical opportunities to mitigate emissions through technological shifts, cleaner energy systems, and material recycling.