Toyota Motor and Idemitsu Kosan have joined hands to develop and mass-produce all-solid-state batteries for electric vehicles, the companies said on Thursday.

The partnership follows an announcement in June by Toyota, the world's biggest automaker by sales, that it would introduce the high-performance batteries to improve the driving range and reduce costs of future EVs in a strategic pivot.

Toyota, which has been slow in adopting pure-battery powered EVs, trumpeted at the time a "technological breakthrough" that addressed durability problems in solid-state batteries and said it was developing means to mass produce those batteries.

Idemitsu and Toyota said in a statement that they would aim to commercialize the next-generation batteries in 2027-28, followed by full-scale mass production.

At a news conference in Tokyo the same day, Toyota President Koji Sato said that the two firms will combine "Idemitsu's materials manufacturing technology and Toyota's battery mass production technology in a full-scale effort to mass-produce solid-state batteries."

"Our two companies will unite their strengths to mass-produce solid-state batteries and to realize innovations originating in Japan," Sato said.

Koji Sato (left), president of Toyota Motor, speaks while Shunichi Kito, president and CEO of Idemitsu Kosan, looks on during a joint news conference in Tokyo on Thursday.
Koji Sato (left), president of Toyota Motor, speaks while Shunichi Kito, president and CEO of Idemitsu Kosan, looks on during a joint news conference in Tokyo on Thursday. | Bloomberg

Automakers around the world are racing to develop all-solid-state batteries, which use solid electrolytes instead of the liquid type.

Solid-state batteries can hold more energy than current liquid electrolyte batteries. Automakers and analysts expect them to speed transition to EVs by addressing their often limited range, which remains a major consumer concern.

An EV powered by a solid-state battery would have a range of 1,200 kilometers and charging time of just 10 minutes, according to Toyota.

Still, such batteries are expensive and are likely to remain so for years.

Idemitsu, Japan's second-biggest oil refiner, has been expanding into EV battery supply chains, increasing its stake in Australian lithium developer Delta Lithium to 15% earlier this year amid a global push by automakers to electrify their fleets.

In its EV business strategy, Toyota aims for annual global sales of 1.5 million units in 2026 and 3.5 million units in 2030.