Yes a complete accounting of the net externalities of each would be very complicated, and I apologize that I am not prepared to present a 200 page research report here in the forum. A bit of napkin math can go a long way.
How much dirt you have to dig up to get a thing isn't really much of a measure of impact though. If I dig up 50,000lbs of dirt to get 138lbs of lithium, but the dirt just goes back to being dirt, no problem. If on the other hand sulfuric acid leeching makes it an uninhabitable wasteland for years, problem.
But yes in the end, recycling batteries is going to be the real big win, where all the components can be reused rather than mined.
How much dirt you have to dig up to get a thing isn't really much of a measure of impact though. If I dig up 50,000lbs of dirt to get 138lbs of lithium, but the dirt just goes back to being dirt, no problem. If on the other hand sulfuric acid leeching makes it an uninhabitable wasteland for years, problem.
But yes in the end, recycling batteries is going to be the real big win, where all the components can be reused rather than mined.