Toyota Just Struck A Key Deal To Make Solid-State Batteries

• Toyota has priority to receive the all-important cathode material for solid-state batteries from a supplier starting in 2028.
• It already has a deal with another company for the solid electrolyte, the other key component for a solid-state battery.
• Toyota says its first solid-state-powered EVs could hit the market as early as 2027.

Solid-state batteries promise to eliminate or mitigate many of the downsides associated with today’s crop of electric vehicle batteries. These batteries are lighter, safer and charge faster, but they’re still in their early days and not being produced at scale due to manufacturing complexities and high costs. 

Toyota has been developing its own solid-state batteries for many years, and it plans to sell its first EVs equipped with the technology in 2027 or 2028. A new deal announced on Wednesday should help things along: The automaker and Sumimoto Metal Mining have struck a joint development agreement to mass-produce cathode materials for solid-state batteries.

The metals company plans to start pumping out the cathode material at scale as early as the financial year starting in April 2028, a company spokesperson told Reuters.

“We will prioritize supplying Toyota, then respond flexibly to market demand,” they said. 

But will this new “highly durable cathode material,” which can supposedly withstand many more charge-discharge cycles than what’s in today’s batteries with far less degradation, give Toyota the edge? Toyota is known as a leader in the number of solid-state patents that it holds, and it is expected to be among the first companies to roll out this technology.

Interestingly, older reports suggested that the first production Toyota to get solid-state batteries isn’t going to be a full EV but a hybrid instead. This could make Toyota’s already popular hybrids even better and more competitive. And if the cost of solid-state batteries would still be too high for use in a large EV battery pack, using them in hybrids first sounds like a sensible first step.

Another key component for solid-state batteries is the solid electrolyte, lithium sulphide, which will come from another Japanese company, Idemitsu Kosan, one of the country’s largest oil refiners. This electrolyte also plays an important role in giving the battery all its superior properties.

But Toyota may not be the first to launch a solid-state production car. Mercedes and BMW are already testing prototypes on public roads, while Nio already offers what it calls a semi-solid-state battery in its ET5 and ET7 models in China. You can’t buy it from Nio—it supposedly costs as much as an ET5 on its own—but you can have it swapped into your vehicle if you’re planning on going on a long road trip where its claimed range of over 650 miles will come in handy.

There are several other semi-solid-state batteries available on Chinese cars, although they can’t match Nio’s remarkable 360 watt hours per kilogram energy density. The BMW i7 solid-state prototype has an even higher energy density of 390 Wh/kg, but it’s purely a test vehicle that won’t be going into production with those specs anytime soon.

Toyota also has competition from Honda to bring solid-state tech to market. Its Japanese rival said in 2024 that it was working on solid-state cells that are 50% smaller, 35% lighter and 25% cheaper than today’s lithium-ion batteries, but it hasn’t provided a clear time frame for when they could go into production.

At the same time, more conventional lithium-ion batteries have been improving consistently. Once Toyota or another manufacturer actually starts putting solid-state batteries in cars, we’ll have a better sense of whether this tech is the moonshot it was cracked up to be.