I did my PhD on rare earth compounds. Rare earth elements are generally not used in lithium ion batteries. The metals most people worry about are cobalt and lit

I did my PhD on rare earth compounds. Rare earth elements are generally not used in lithium ion batteries. The metals most people worry about are cobalt and lithium. Rare earths are elements like lanthanum or ytterbium. Rare != rare earth. https://en.wikipedia.org/wiki/Rare-earth_element https://en.wikipedia.org/wiki/Rare-earth_element (Or perhaps you're thinking about electric motors, which can use rare earths like neodymium.)