As we wean ourselves away from fossil fuels and ramp up our reliance on alternatives, batteries become ever more important for two main reasons. First, we need grid-scale batteries to store excess electricity from time-varying sources such as wind and solar. Second, we use them to power electric vehicles, which we are now producing at the rate of about 15 million a year worldwide.

So far, the battery of choice is the lithium-ion battery. In addition to lithium, these rely on four metals — copper, nickel, cobalt, and manganese. In the podcast, Adam Simon explains the role these metals play in a battery. He then describes the geological context and origin of the economically viable deposits from which we extract these metals.

Simon is a professor of economic geology at the University of Michigan.