Mercedes-Benz has signed a joint testing agreement with ProLogium to evaluate its Gen4 solid-state battery cells. The deal gives Mercedes priority access, not exclusivity, to test the technology for electrical, thermal, and safety performance. ProLogium claims its anode-less lithium ceramic cells can reach 430-470 Wh/kg, which could cut battery weight and support longer range or smaller packs. The testing builds on nearly a decade of cooperation and follows Mercedes' 2025 road test with Factorial Energy cells. ProLogium is moving toward mass production, with a Taiwan gigafactory already shipping cells and a new facility in Dunkirk, France planned to start Gen4 output in 2028. The European plant is part of a broader push to reduce reliance on Chinese battery manufacturing, which still dominates global capacity. For EVs, higher energy density can lower material use and lifecycle emissions, but the climate benefit depends on clean production and end-of-life recycling. This agreement is an early step toward commercial solid-state adoption.
