Idemitsu Launches Electrolytes Plant for Solid-State Batteries for Toyota EVs
By Reuters | 29 Jan, 2026

Japan's no. 2 oil refiner will produce electrolytes for next-generation solid-state batteries to power Toyota EVs slated to debut 2027-28.

Japan’s No. 2 oil refiner Idemitsu Kosan said on Thursday it has taken a final investment decision and begun construction of a large pilot plant to produce solid electrolyte for all-solid-state lithium-ion batteries.

Idemitsu is collaborating with Toyota Motor to commercialise next generation batteries and supporting the automaker's goal of launching electric vehicles equipped with all-solid-state batteries by 2027-2028. The decision marks a move into the next phase toward commercialisation.

Automakers and battery suppliers worldwide are racing to develop solid-state batteries, touted as crucial for longer-lasting, safer, and more affordable EVs.

Idemitsu is developing mass-production technology for solid electrolytes, a core component of solid-state batteries, and is manufacturing samples at two small-scale demonstration facilities, including one focused mainly on materials development for Toyota. 

Based on results from the pilot facility, Idemitsu plans to build a large-scale pilot plant with production capacity of several hundred metric tons per year. The solid electrolyte produced by this plant will be used in all-solid-state batteries for Toyota's EVs.

Idemitsu aims to complete construction in 2027 at its Chiba plant near Tokyo. Construction has been contracted to Chiyoda Corp.

(Reporting by Yuka Obayashi, Editing by Louise Heavens)