Idemitsu Kosan and Toyota Motor Corporation have partnered to develop mass production technologies for solid electrolytes that will improve productivity, establish a supply chain, and help support the mass production of all-solid-state batteries.

Through this collaboration, the two companies are looking to ensure the successful commercialization of all-solid-state batteries between 2027 and 2028, followed by full-scale mass production. The collaboration itself will focus on sulfide solid electrolytes, a material that can helps BEVs achieve a high capacity and power output. Sulfide solid electrolytes have a softness and adhesiveness to other materials, making them suitable for battery mass production.

In the first phase of the collaboration, the companies will develop sulfide solid electrolytes with attention to quality, cost, and lead times, which they believe will realize a mass-production demonstration of sulfide solid electrolytes using an Idemitsu pilot facility.

Then, in the second phase, through the construction and startup of a large pilot facility, Idemitsu will promote sulfide solid electrolyte manufacture, and obtain mass production technologies. Toyota will likewise promote the development of both all-solid-state batteries in which sulfide solid electrolytes are used and BEV development in which the batteries are incorporated. The OEM will then support and ensure the market launch of BEVs equipped with with all-solid-state batteries before the 2027 to 2028 deadline. At the third and final phase, the companies will then study future full-scale mass production and commercialization practices, based on the results of phase two.