Environmental Impact Assessment of LiNi1/3Mn1/3Co1/3O2 Hydrometallurgical Cathode Recycling from Spent Lithium-Ion Batteries

The global demand for lithium-ion batteries (LIBs) has witnessed an unprecedented increase during the last decade and is expected to do so in the future. Although the service life of batteries could be expanded using Circular Economy approaches such as repair or remanufacture, batteries will inevitably become a huge waste stream as electric vehicles gain popularity. Battery recycling reintroduces end-of-life materials back into the economic cycle and prevents landfill scenarios. The reclamation of materials from spent batteries in general, and cathodes in particular, reduces the pressure over finite critical raw materials such as cobalt, nickel, lithium, or manganese and avoids severe heavy metal contamination issues associated with battery disposal. To establish a sustainable battery-recycling industry, the environmental impact assessment of cathode-recycling approaches is urgently needed. Accordingly, a life-cycle assessment methodology is applied to quantify and compare the environmental impacts of nine hydrometallurgical laboratory-scale LIB cathode-recycling processes in 18 impact indicators such as global warming potential. The LiNi1/3Co1/3Mn1/3O2 cathode is selected given its predominant market share among electric vehicles. Hydrometallurgical recycling approaches based on inorganic acid-leaching (hydrochloric, sulfuric, and phosphoric acids), inorganic alkali-leaching (ammonia/sodium sulfite), organic leachates (citric, formic, or lactic acids), and bio-leaching processes are analyzed. Scaling up the recycling to 1 kg cathode, global warming values from 25.1 to 95.2 kg·CO2-equiv per 1 kg of recycled cathode are obtained. The processes based on HCl and H2SO4/H2O2 and the autotrophic bio-leaching process are preferred to lower greenhouse gas emissions and toxicity- and resource-related potential impacts. The choice of chemicals, the energy consumption, and more importantly, material efficiency emerge as the cornerstones to achieve environmentally sustainable processes. A sensitivity analysis demonstrates the potential to reduce the impacts by transitioning to a renewable energy mix, reaching a global warming value of 5.01 kg·CO2-equiv·kgcathode–1. These results provide guidance toward further process optimization through eco-design approaches, securing the long-term sustainability of LIBs.