It sounded amazing—this sort of technology could transform the EV industry. But many quickly wondered if it was all too good to be true. Now, Donut Lab is releasing a series of videos that it says will prove its technology has the secret sauce. Let’s dig into why this company is making news, why many experts are skeptical, and what it all means for the battery industry right now.

Solid-state batteries could deliver the next generation of EVs. In place of a liquid electrolyte (the material that ions move through inside a battery), the cells use a solid material, so they can be more compact. That means a significantly longer range, which could get more people excited to drive EVs.

The problem is, getting these batteries to work and making them at the large scale required for the EV industry hasn’t been a simple task. Some of the world’s most powerful automakers and battery companies have been trying for years to get the technology off the ground. (Toyota at one point said it would have solid-state batteries in cars by 2020. Now it’s shooting for 2027 or 2028.)

While it’s been a long time coming, it does feel as if solid-state batteries are closer than ever. Much of the progress so far has been on semi-solid-state batteries, which use materials like gels for electrolytes. But some companies, including several in China, are getting closer to true solid state. The world’s largest battery company, CATL, plans to manufacture small quantities in 2027. Another major Chinese automaker, Changan, plans to start testing installation of all-solid-state batteries in vehicles this year, with mass production expected to begin next year.

Still, Donut Lab surprised the battery industry when, in a video released in early January ahead of the Consumer Electronics Show in Las Vegas, the company claimed it would put the world’s first all-solid-state battery into production vehicles.

One of the splashiest claims in the announcement was that cells would have an energy density of 400 watt-hours per kilogram (the top commercial lithium-ion batteries today sit at about 250 to 300 Wh/kg). It was also claimed that the cells could charge in as little as five minutes, last 100,000 cycles, and retain 99% of capacity at high and low temperatures—while costing less than lithium-ion cells and being made from “100% green and abundant materials with global availability.”

Many experts were immediately skeptical. “In the solid-state field, the technical barriers are very high,” said Shirley Meng, a professor of molecular engineering at the University of Chicago, when I spoke with her last month. She’d recently attended CES and visited Donut Lab’s booth. “They had zero demo, so I don’t believe it,” she says. “Call me conservative, but I would rather be careful than be sorry later.”

“It’s one of those things where nobody knows—they’ve never heard of it,” said Eric Wachsman, a professor at the University of Maryland and cofounder of the solid-state battery company Ion Storage Systems, in a January interview. “They came out of nowhere.”