Most house batteries use LFP. They do not contain rare earths. I've never checked, but I presume that's true for grid scale batteries too as the cost per kWh

Most house batteries use LFP. They do not contain rare earths. I've never checked, but I presume that's true for grid scale batteries too as the cost per kWh stored is roughly the same LCM, but LFP last for an order of magnitude more cycles (and weigh more, which isn't a concern for grid storage).