Tesla is using Lithium Iron Phosphate in Model 3s and Ys manufactured in China. It's giving buyers of the SR+ in North America the option of the LFP version if they want faster delivery.

The downside of LFP is lower energy density which means an LFP Model 3 has a slightly reduced range compared to the Lithium Ion version.

The upside is the LFP likes to be charged to 100% where as Lithium Ion prefers 90% charges.