Decoding Cobalt’s Influence: An Analysis of Environmental Impacts in the Production of NMC Cathode Active Materials for Lithium-ion Batteries

The increased use of lithium-ion batteries has raised concerns about the sustainability of their usage, prompting the need for an environmental assessment. This study evaluates and compares the environmental impacts of NMC 111 and NMC 811 cathode active materials (CAMs) using Life Cycle Assessment (LCA). To improve the accuracy of the assessment, process simulation with HSC Chemistry was employed to model the production of cobalt sulfate (CoSO₄), a key precursor for NMC cathodes. Using the simulated process data, a custom Life Cycle Inventory (LCI) was generated and the environmental impacts of CoSO₄ production were assessed using the ReCiPe 2016, midpoint impact assessment method in OpenLCA were. This custom cobalt sulphate dataset is integrated into the Ecoinvent database by replacing the default CoSO₄ input in NMC 111 and NMC 811 inventories, allowing for a comparative LCA of both chemistries The results indicate that the modelled cobalt sulfate production route has a lower environmental impact than reported literature values, with a GWP of 12.1 kg CO₂-eq per kg of CoSO₄. The majority of emissions and resource use were found to stem from extraction and early processing stages, rather than final refining. When applied to NMC 111 and NMC 811, the results highlight key trade-offs: NMC 111 exhibits a higher GWP (22.4 kg CO₂-eq/kg) due to its greater cobalt content, while NMC 811, with lower cobalt dependency, has a slightly reduced footprint (21.8 kg CO₂-eq/kg). However, the increased nickel content in NMC 811 introduces additional environmental burdens, emphasizing the need for a balanced assessment when selecting cathode chemistries.