TOKYO (Reuters) -Toyota and Sumitomo Metal Mining said on Wednesday they have made advances in the development of cathode materials for all-solid-state batteries for electric cars, and have agreed to work together to mass produce those materials.

Solid-state batteries hold the promise of improved safety, a longer lifespan and faster charging compared with conventional lithium-ion batteries that use flammable liquid electrolytes.

But mass adoption remains some way off due to constraints in raw material availability, intricate manufacturing processes and the resultant high costs.

Toyota, the world’s biggest automaker by sales, is looking to launch EVs with all-solid-state batteries in 2027 or 2028.

The Japanese companies said their joint research since 2021 on cathode materials has focus

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