Donut Lab validation: more glimpse than full disclosure

Finnish battery start-up Donut Lab could prove the game-changer needed to usher in the solid-state era, or it might be the hoax of the decade. At CES 2026, the company declared a host of impressive metrics about its upcoming solid-state battery but failed to back them up with any sort of details. No third-party verification, no clarification on core materials or production processes, no product—instead of showing the battery itself at CES, the company displayed the case in which it was to be packaged.

Industry players and electric vehicle (EV) enthusiasts were almost universally sceptical, with responses ranging from ‘too good to be true’ to  ‘prank’, ‘BS’, ‘hoax’, ‘witchcraft’, and ‘scam’. Was this another Nikola Motors in the making?

Extraordinary claims

The claims were ground-breaking: a market-ready US$130kWh solid-state battery with 400Wh/kg energy density, a five-minute charge time and a 200-year lifespan (or 100,000 cycles)—all while avoiding the use of rare earth materials. The unit can reportedly operate at temperatures from -30 to 100 degrees Celsius, with no liquid cooling required at 5C charging rates. Taken individually, they are impressive but not impossible. Researchers are already exploring solid-state sodium-ion and lithium-sulphur solid-state cells that avoid any use of rare earths. The energy density is also a feasible advance from what other solid-state and semi solid-state developers have verified—Factorial Energy and Stellantis validated an automotive-sized solid-state battery cell with 375Wh/kg energy density in April 2025, albeit over 600 cycles (far fewer than Donut Lab’s claimed 100,000).

What created incredulity was Donut Lab’s claim to have addressed all these metrics in one go, without the usual trade-offs, and with apparently a tiny engineering team. The entire company headcount is less than 100, and the CES contingent consisted of predominately marketing people with a single engineer. “Solid-state batteries have been around for years, but no-one has cracked them at scale, even the top battery companies in the world,” points out Nick Molden, Founder and Chief Executive of Emissions Analytics. How did this tiny company manage such achievements?

Given the scale of Donut Lab’s extraordinary claims, it needed to follow-up with some form of scientific and engineering verification, peer-review or patent disclosures.

VTT steps in

In late February 2026, Donut Lab finally took the first step and publicly shared the findings of independent testing by Finland’s state-owned VTT Technical Research Centre. The tests tackled just one aspect of the battery: charging performance. In a shared video, an engineer walks viewers through a series of seven charging tests on a 94Wh pouch cell. The cell was charged at various rates up to 11C. With the 5C test, it charged to 80% in less than ten minutes and 100% in about 13 minutes, with a peak temperature of 47 degrees Celsius. The 11C test charged the cell to 80% in a mere 4.6 minutes, with a full charge taking less than eight minutes and producing a top temperature of 63 degrees Celsius.

Overall, the results confirmed some of Donut Lab’s claims but also raised potential issues. Cooling is one of them. In testing, the battery cell was placed between large aluminium heat sinks for passive thermal management but still managed to hit high temperatures in some cases. Charging at 11C and using two thermal heat sinks the temperature hit 63 degrees Celsius; using only one heat sink it hit 90 degrees. This implies some sort of active cooling will be required.

For now, key details on the battery chemistry, the source of the underlying innovation, and the 100,000-cycle lifespan remain unverified. Independent EV advocate and researcher MissGoElectric has posited a theory that the base technology comes from fellow Finnish company Nordic Nano, which has been developing nanotechnology and silicon-based battery solutions, among other things. This is supported by unexplained photos of the two companies’ leadership teams together at CES and Nordic Nano posting Donut Lab press releases on its social media. Neither company has responded to the speculation.

Promise vs delivery

Solid-state batteries have gone through multiple hype cycles over the past decade and attracted billions in venture capital. Various players are pursuing potential solutions with the technology, but there’s a big difference between promise and delivery, laboratory success and commercial scaling.

“What ultimately matters for long‑term success is customer validation and demonstrated delivery, not just announced targets,” says Factorial Energy Chief Executive Siyu Huang. Factorial is pursuing semi solid-state batteries and has attracted backing from such big-name players as Mercedes-Benz, Stellantis and Hyundai-Kia. Its stats fall short of Donut Lab’s, with energy density of 375Wh/kg over 600 cycles and an 18-minute charging time from 15% to 90% charge, and it understandably doubles down on the credibility angle.

As Huang tells Automotive World: “As the sector matures, credibility is increasingly defined by customer partnerships. It’s not about a singular customer but a broad and growing base of customers, expanding real-world performance data, and clearly defined pathways to scalable manufacturing. These proof points distinguish promising concepts from technologies that are truly ready for scale.”

Donut Lab’s primary customer is its parent company, Verge Motorcycles. Verge management has said that the first battery is in production at a plant in Finland and will arrive on the market later in 2026. As for the battery verification process, Donut Lab intends to drip feed validation details on the website I Donut Believe, potentially with the aim of raising funding and/or creating media buzz. The initial results might be positive enough to warrant interest from investors, but their limited scope could suggest there are other metrics on which the company would rather not shine a spotlight.