Comparative life cycle assessment of LFP and NCM batteries including the secondary use and different recycling technologies

Abstract

Lithium iron phosphate (LFP) batteries and lithium nickel cobalt manganese oxide (NCM) batteries are the most widely used power lithium-ion batteries (LIBs) in electric vehicles (EVs) currently. The future trend is to reuse LIBs retired from EVs for other applications, such as energy storage systems (ESS). However, the environmental performance of LIBs during the entire life cycle, from the cradle to the grave, has not been extensively discussed. In this study, life cycle assessment (LCA) was used to quantify and compare the environmental impacts of LFP and NCM batteries. Apart from the phases of production, the first use in EVs, and recycling, the repurposing of retired LIBs and their secondary use in the ESS were also included in the system boundary. Also, the environmental impacts of various recycling processes were evaluated. The LCA results suggested that the NCM battery had better comprehensive environmental performance than the LFP one but shorter service life over the whole life cycle. In China, the first and secondary use phases contributed most to the environmental impacts with electricity mostly generated from fossil fuels. The LIB production phase was relevant to all assessed impact categories and contributed more than 50% to Abiotic Depletion Potential (ADP elements) particularly. The environmental loads could be mitigated through the recovery of metals and other materials. And, hydrometallurgy was recommended for recycling waste LIBs by better environmental advantages than pyrometallurgy and direct physical recycling. Sensitivity analysis revealed that by optimizing the charge-discharge efficiency of LIBs, particularly LFP batteries, all environmental burdens could be considerably decreased. Therefore, improving the electrochemical performance of LIBs and increasing the use proportion of clean energy were crucial to reduce the environmental impacts over their entire life cycle.