Japanese chemical company Idemitsu Kosan has begun construction of a large-scale pilot plant for producing solid electrolytes. The decision follows successful internal testing at two smaller plants, where samples have already been produced and production technologies have been validated. The new plant is being built at the Chiba site and is scheduled for completion by the end of 2027. It is intended to have a production capacity of several hundred tons per year.

Idemitsu views solid electrolytes as a critical component of all-solid-state batteries (ASSB), which are to be used in battery-electric vehicles in the future. Idemitsu is collaborating with Toyota, which plans to launch its first series-production vehicles with ASSB in 2027 or 2028. According to Idemitsu, the materials produced at the new plant are intended for use in these batteries.

The development of the mass production process is being carried out as part of a green innovation support program run by the Japanese NEDO agency. In addition to the pilot plant for solid electrolytes, Idemitsu is building a plant to produce lithium sulfide, an important intermediate product. Its completion is scheduled for June 2027. The company states that it uses sulfur, a byproduct of petroleum processing, in the manufacturing of solid electrolytes. Idemitsu has been investigating this raw materialʼs suitability for battery technology since the mid-1990s.

Source:https://www.idemitsu.com/jp/news/2025/260129.pdf