Lithium-ion battery recycling routes: An environmental assessment in the context of the European battery regulation

This study evaluates the environmental impacts of three primary lithium-ion battery (LIB) recycling processes—pyrometallurgical, hydrometallurgical, and direct recycling—through a life cycle perspective. The analysis considers lithium iron phosphate (LFP), nickel-manganese-cobalt (NMC), and nickel-cobalt-aluminium (NCA) cathode chemistries, both individually and as a projected 2031 mixture. Pyrometallurgical recycling exhibits the highest climate change impacts due to CO₂ emissions during high-temperature calcination. In contrast, direct recycling exhibits the lowest environmental impacts across all impact categories assessed. However, its industrial scalability and the effective cathode material separation for mixed input feedstocks remain significant challenges. Hydrometallurgical recycling is heavily influenced by the environmental burdens of input materials, with over 70% of greenhouse gas (GHG) emissions attributable to reagents like sulfuric acid and sodium hydroxide, which also contribute to marine eutrophication and respiratory effects. The graphite produced from the hydrometallurgical process is often incinerated due to its low quality and limited recyclability, which increases net emissions and brings the environmental impacts of hydrometallurgy closer to those of pyrometallurgical methods. Interestingly, although LFP recycling benefits from reduced processing chemical and energy demands, the lower environmental credits associated to the recovered materials result in relatively high net impacts. These findings emphasize the need to consider the full life cycle and especially the environmental value of recovered materials when assessing the environmental sustainability of LIB recycling processes. Future improvements should focus on increasing material recovery rates, minimizing processing emissions and chemicals demand, and incorporating renewable energy to reduce electricity-related impacts. Tailoring recycling technologies to specific chemistries and generating high-resolution data from industrial processes will be essential for optimizing recycling strategies and aligning them with sustainability goals.