--- title: Donut Lab’s Solid-State Battery Passes Its First Independent Test description: VTT confirms Donut Lab’s solid-state cells charge to 80% in 4.5 minutes. It is the first of six headline claims to be independently verified. author: Darie Nani (Editor-in-Chief) date: 2026-02-23T20:41:01.000Z updated: 2026-02-26T18:01:30.756Z canonical: https://www.sovereignmagazine.com/article/donut-lab-s-solid-state-battery-passes-its-first-independent-test image: https://cdn.nanimediahouse.com/donut-lab-solid-state-battery-vtt-test.webp categories: Science & Tech content_type: News region: Finland publication: Sovereign Magazine --- Finland’s VTT Technical Research Centre has [confirmed](https://electrek.co/2026/02/23/donut-lab-vtt-solid-state-battery-test-results-fast-charging/) that Donut Lab’s solid-state cells charge to 80% in 4.5 minutes at an 11C rate. Report VTT-CR-00092-26, published today, is the first independent verification of any specification the Helsinki startup has claimed. Donut Lab made six [headline claims at CES](https://www.sovereignmagazine.com/article/solid-state-batteries-how-donut-lab-called-the-industry-s-bluff-and-won): 400 Wh/kg energy density, 100,000 cycle life, extreme temperature tolerance, lithium-ion cost parity, construction from non-geopolitically sensitive materials and sub-five-minute charging. Any of those would be significant on its own. The materials claim matters for supply chain independence from Chinese-controlled lithium and cobalt processing. The energy density matters for range. The cycle life matters for total cost of ownership. But there is an argument that fast charging was the strongest card to play first. Charging time is the most visible friction point in the switch from petrol to electric. It is the spec a consumer encounters at a forecourt. If Donut Lab wanted to lead with the claim that would generate the most immediate commercial credibility, this was it. ## The drip-feed What is interesting is how Donut Lab is going about this. It could have responded to the [fraud accusations](https://www.sovereignmagazine.com/article/the-battery-industry-called-donut-lab-a-fraud-then-announced-its-own-solid-state-plans) by submitting everything for testing at once. Instead it handed cells to VTT (one of the most respected research institutions in Europe, with over 80 years of applied science work for the Finnish government and private sector) and let them publish whatever they found, starting with arguably its strongest selling point. You do not do that unless you know what the results are going to say. CEO Marko Lehtimäki [confirmed as much](https://www.electrive.com/2026/02/23/donut-lab-presents-first-data-on-controversial-solid-state-battery/) to Electrive: ‘if we presented full validation immediately, controversy would shift to scalability questions.’ The company has even launched a dedicated site ([idonutbelieve.com](https://idonutbelieve.com/)) to publish VTT results as they arrive. Rather than flinch at the backlash, Donut Lab has turned it into a marketing campaign. Five claims remain unverified and will arrive on Donut Lab’s schedule, not its detractors’. ## Five more to go None of this is settled, obviously. Energy density, cycle life, temperature range, material sourcing and cost all still need independent verification, and Lehtimäki has said more VTT reports are coming in 6 days as of publishing. Two months ago the question was whether Donut Lab had anything real at all. After today, it is whether the rest holds up. ## Further Context **Q: Why do not EVs use solid-state batteries?** Solid-state batteries replace the liquid electrolyte in conventional lithium-ion cells with a solid material, which in theory allows higher energy density, faster charging and better safety. The reason they are not in vehicles yet is manufacturing. Solid electrolytes are brittle and crack under the expansion and contraction that occurs during charge cycles, which limits how many times a cell can be recharged before it degrades. Every major battery manufacturer (Toyota, Samsung SDI, CATL, QuantumScape) has a solid-state programme, but none has achieved mass production. Most are targeting 2027–2030 for limited commercial output. **Q: What is VTT Technical Research Centre of Finland?** VTT is Finland’s state-owned applied research organisation, founded in 1942. It is the largest research and technology institution in Finland and was ranked fourth in Europe by European Research Ranking for success in competitive research funding. VTT operates as a non-profit and receives roughly 70% of its income from commissioned research for private companies and public bodies. In 2024 it became the first non-American partner selected for a US Department of Energy ARPA-E programme, working alongside Lawrence Livermore National Laboratory on fusion energy research. Its involvement in testing Donut Lab’s cells carries weight precisely because of this institutional credibility. **Q: What is a donut battery?** The Donut Battery is a branded all-solid-state battery cell manufactured by Donut Lab, a Helsinki-based startup. The company claims it delivers 400 Wh/kg energy density, charges fully in five minutes, lasts 100,000 cycles and uses no geopolitically sensitive raw materials such as cobalt or nickel. Donut Lab says the cells are already in gigawatt-hour level production and are being installed in Verge Motorcycles electric vehicles, though deliveries have slipped from Q1 to at least April 2026. As of February 2026, only the fast charging specification has been independently verified.