Life Cycle Assessment of Direct Recycling Processes for Lithium Iron Phosphate Battery

Sammanfattning

The rise of Lithium Iron Phosphate (LFP) batteries in electric vehicles and energy storage requires developing sustainable strategies for managing these batteries after their useful lives. The direct recycling method aims to recover and regenerate active materials with minimal energy and processing inputs, offering potential environmental advantages over conventional, energy and chemically-intensive pyrometallurgy and hydrometallurgy. This thesis performs a comprehensive, bottom-up Life Cycle Assessment (LCA) to quantify the environmental performance of a wide array of emerging direct recycling technologies for LFP prismatic cells. Using a functional unit of 1 kWh of battery capacity and the Environmental Footprint (EF) 3.1 method, this study constructs detailed inventories for seven cathode, six anode regeneration pathways and one electrolyte recycling pathway, that identifies key environmental contributions and trade-offs.The results shows that the selection of appropriate technology for recycling can dramatically reduce the overall footprint with significant variation observed among the different pathways. Within the process, approaches with the lowest chemical and energy intensity such as the recrystallization/molten salt method for cathodes and the solvent-free flash joule heating for anodes demonstrate the lowest direct environmental impacts. The analysis identifies critical contributions in the upstream production of reagents, with the GVL solvent, DES components (glycerine and choline chloride), and bio-based L-threonine contributing significantly to the overall impacts of their respective pathways.Crucially, this study demonstrates that an evaluation based on unit-process level burdens alone is insufficient. When the analysis is expanded to include the environmental benefits of avoiding new material production, the environmental contribution shifts significantly. For example, the hydrothermal direct recycling method, despite a high process-level climate impact, ultimately achieves one of the lowest net climate burdens because of its high material recovery yield. When benchmarked against conventional methods, the performance differences are significant: optimized direct recycling pathways evaluated in this study provide a substantial net climate benefit, ranging from -8.30 to -27.45 kg CO₂-Eq/kWh. In contrast, both pyrometallurgy and hydrometallurgy, as per other literatures results in a net climate burden of +6.45 kg CO₂-Eq/kWh and +48.5 kg CO₂-Eq/kWh, respectively.The optimized direct recycling pathways are observed to be most effective in reducing acidification, thus providing a more balanced and holistically beneficial environmental profile.