Grave-to-cradle life cycle environmental impact assessment of recycling of spent lithium-ion batteries
Le résumé fourni par la source
In 2022, domestic transportation accounted for 28% of the total domestic emissions in the United Kingdom. With increasing technological innovation, electric vehicles can support sustainable transport transitions. However, this also increases the need for effective and sustainable end-of-life management strategies for spent lithium-ion (Li-ion) batteries informed by life cycle assessment. This study investigates grave-to-cradle environmental impacts by conducting attributional life cycle assessment of recycling of spent lithium-ion batteries considering 1 kg of cathode materials produced as the functional unit. The system boundary included transportation, disassembly, recycling, material conversion and cathode production. Furthermore, six different scenarios were considered to account for variation in % of type of battery chemistries used from the year 2026 to 2050 and electricity grid emissions as intermediate mix and net zero advanced mix. Calculations were performed for NCA (lithium nickel cobalt aluminium oxides), NMC (lithium nickel manganese cobalt oxides), NMC532 (nickel: manganese: cobalt = 5:3:2), NMC622 (nickel: manganese: cobalt = 6:2:2), (NMC811: nickel: manganese: cobalt = 8:1:1), using hydrometallurgical, pyrometallurgical and direct recycling route for all six scenarios. The findings indicated that for the year of calculation as 2026, emissions for various stages for 1 kg of cathode produced ranged from 133 gCO2 equivalent (gCO2e) to 38 kgCO2e (transportation), 530 gCO2e to 1622 kgCO2e (recycling), 0 to 208 gCO2e (material conversion) and lastly 0 to 26 kgCO2e (cathode production). For the year of calculation as 2050, these emissions were 2.3 to 46 (transportation), 15 to 431 (recycling), 0 to 2.7 (material conversion), and 0 to 16 kgCO2e (cathode production) per kg of cathode material produced. Furthermore, for the year 2050, recycling processes reduced emissions by 35–60% (specifically, 35-40% by pyro metallurgical process, 60% by hydro metallurgical process) compared to virgin manufacture per kg of cathode production, depending on chemistry and route. For the intermediate grid mix (high in fossil fuels) compared to advanced net zero mix the variation in emissions were 30-40%. This research provides a novel framework to conduct life cycle assessment of recycling technologies, by including time-dependent data to account for adoption of various battery chemistries and improvements in electricity grid.
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