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| Fig. 1: Electric vehicle. (Source: Wikimedia Commons) |
As the global transportation sector trends toward decarbonization, electric vehicle sales around the world have risen dramatically, from 120,000 in 2012 to 6.6 million in 2021. [1,2] With more electric vehicles being sold, more batteries - particularly lithium-ion batteries - need to be produced, and more battery materials need to be mined. [2,3] One of these battery materials, of course, is lithium metal. As more cars electrify, the concern of scaling up the world's lithium production becomes increasingly salient. [3] To understand and address this concern, we must first examine the global lithium budget, thus motivating us to answer the following question: what is the total amount of lithium metal used to make electric cars (pictured in Fig. 1) in all the world, measured in kg per year and in US dollars per year?
We will answer this question by multiplying the total number of electric cars made in 2021 by the amount of lithium metal in a single electric car. In 2021, 6.6 million electric vehicles (EVs) were sold. [1,2] Moreover, it has been estimated that the Li-ion battery pack for a single car contains about 8 kg of lithium metal. [3,4] So, we can find the total mass of lithium metal used to make EVs in 2021 as follows:
Let's check this calculation by multiplying together (1) global lithium metal consumption in kg per year and (2) the percentage of global lithium demand captured by electric vehicles. The first number equals 93 million kilograms per year in 2021. [4,5] The second number was equal to 14 percent in 2015. [6] I was unable to find a more recent number, so I will use the 14 percent as a lower bound for the actual percentage in 2021. In other words, we conclude at least the following amount of lithium metal was used to make electric vehicles in 2021:
We will carry out another cross-check by multiplying global lithium metal consumption in 2021 by the percentage of global lithium used for batteries. The latter quantity is reported to equal 74 percent. [5] So, we can say that no more than the following amount of lithium metal was used to make electric vehicles in 2021:
Notice that our 52.8 million kg value falls within the lower and upper bounds we have computed. Now, we will convert this value into US dollars per year. The conversion factor is $69 kg-1. [7] One can find this by first knowing that lithium carbonate (Li2CO3) cost $13 per kg in 2019 and then multiplying that cost by 74/14 (molar mass of Li2CO3 divided by that of Li). [7] Lithium metal's cost is then:
Thus, we find that the following amount of lithium (in US dollars) was used to make electric vehicles in 2021:
We have determined that 52.8 million kg - or, equivalently, $3.64 billion - of lithium metal was used to make electric vehicles in 2021. We have also checked this value by identifying a lower bound of 13 million kg per year and an upper bound of 68.8 million kg per year.
© Ajay Ravi. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] "Global EV Outlook 2022," International Energy Agency, May 2022, p. 4.
[2] G. Clark, "Electric Vehicle Cobalt Demand: Implications on Subsea Resources," Physics 240, Stanford University, Fall 2022.
[3] D. Castelvecchi, "Electric Cars and Batteries: How Will the World Produce Enough?," Nature 596, 336 (2021).
[4] B. Muñoz-Cerro, "The Lithium Triangle," Physics 240, Stanford University, Fall 2022.
[5] "Mineral Commodity Summaries 2022, U.S. Geological Survey, January 2022, p. 100.
[6] D. Coffin and J. Horowitz, "The Supply Chain for Electric Vehicle Batteries." U.S. International Trade Commission, December 2018, p. 10.
[7] H. S. Hirsh et al., "Sodium-Ion Batteries Paving the Way for Grid Energy Storage," Adv. Energy Mater. 10, 2001274 (2020).
