You don’t need a lot of lithium when you have gravity.
Solar and wind power are now the cheapest sources of electricity in most of the world. (Solar power dropped in cost by a staggering 89% over the last decade.) But one of the reasons that it’s challenging to switch fully to renewable energy is the problem of intermittency: The sun doesn’t always shine and the wind doesn’t always blow, and it’s still relatively expensive to use batteries to store energy.