Factorial Energy has signed a joint development agreement with Japan’s Mitsui Kinzoku for solid electrolytes, the latest in a run of partnerships its chief executive says are necessary because no single company can bring all-solid-state batteries to market. ProLogium, which is building Europe’s solid-state gigafactory at Dunkirk, is already mass-producing all-solid-state cells in Taiwan. Factorial […] This story continues at The Next Web