Ultium Cells, the battery joint venture between General Motors and South Korea's LG Energy Solution, plans to retrofit its Spring Hill, Tennessee, plant to become the world's first mass producer of lithium manganese-rich (LMR) prismatic battery cells. The upgrade is scheduled to begin later this year and construction is expected to finish in 2028, although production timing has not been disclosed. LMR cells could provide 33% higher energy density than lithium iron phosphate (LFP) cells, another lower-cost chemistry. GM has previously targeted 2028 for commercial LMR production at a U.S. facility. The plant currently makes LFP cells for energy storage systems, while GM's battery leader has said the automaker may shift away from LFP in favor of LMR. The project is projected to create 500 jobs.