Environmental trade-offs and externalities of electrochemical-based batteries: Quantitative analysis between lithium-ion and vanadium redox flow units

This study aims to increase the scientific knowledge of the environmental impacts and externalities of two promising electrochemical-based techniques for large-scale stationary energy storage: lithium nickel cobalt manganese (NCM) and vanadium redox flow (VRF) batteries. The global warming potential (GWP) and cumulative energy demand (CED) for NCM and VRF batteries are 28 kg CO2eq and 410 MJ and 186 kg CO2eq and 3080 MJ, respectively, for the provision of 1 MWh of electricity. While the trend of the environmental externality results is proportional to the environmental impact results, the environmental costs from GWP and terrestrial ecotoxicity impacts contribute the largest share of the total environmental costs for both batteries. Overall, NCM batteries have favorable environmental performance in terms of their impact values and externalities but still show relatively higher contributions in human toxicity and ozone layer depletion impacts, based on their high resource uses. The VRF batteries, on the other hand, report higher impacts in abiotic depletion, GWP and terrestrial ecotoxicity, mainly due to their great mass of the electrolyte. Our results highlight the importance of substituting the active metals with low-impact metals or carefully considering the origin of key materials while also taking advantage of the properties of the battery to carefully assess possible advancements in battery design. The environmental externality results also provide essential information for the future development of battery industries for stationary applications with energy and environmental benefits.