Life cycle assessment of natural graphite production for lithium-ion battery anodes based on industrial primary data

Abstract

The production of battery materials has been identified as the main contributor to the greenhouse gas (GHG) emissions of lithium-ion batteries for automotive applications. Graphite manufacturing is characterized by energy intense production processes (including extraction), mainly being operated in China with low energy prices and a relatively high GHG emission intensity of electricity generation.Industrial scale primary data related to the production of battery materials lacks transparency and remains scarce in general. In particular, life cycle inventory datasets related to the extraction, refining and coating of graphite as anode material for lithium-ion batteries are incomplete, out of date and hardly representative for today's battery applications. Nevertheless, primary life cycle inventory data of battery materials like graphite, produced on an industrial scale are crucial for a robust evaluation of batteries for electric vehicles, material sourcing and development of robust decarbonization strategies.This paper addresses this issue by first providing a comprehensive overview of the existing graphite datasets and their original sources, and outlining the reasons for wide variations of reported environmental impact results. Furthermore, this paper aims at closing existing data gaps by providing transparent primary data from a Chinese graphite producer from 2019 and assessing the environmental impacts (cradle-to-gate) in form of a life cycle assessment (LCA) for a vertically integrated graphite production. The life cycle inventory covers material, water, energy flows and direct emissions associated with the production of natural graphite anode material for an automotive battery application and associated transport activities along the supply chain. The results of the LCA show that the production of 1000 kg of natural graphite anode material has a global warming potential (GWP) of approximately 9616 kg CO2eq. The subsequent uncertainty analysis in the form of a Monte-Carlo-Analysis with 10000 runs reveals that the 95% confidence interval is in the range between 9297 and 9940 kg CO2eq. This value is more than four times higher than the reported GWP of battery-grade graphite in the ecoinvent database version 3.7.1.