Donut Lab says its solid-state batteries will enter production this year, but experts question the claims

Donut Lab’s solid-state battery production promise

Startup says batteries could reach production this year, but experts doubt parts of the stated performance

Finnish start-up Donut Lab has announced what it describes as a breakthrough in solid-state batteries-often labelled the “holy grail” of battery technology because of their high energy density, long service life and potential for rapid charging. Donut Lab, a spin-off from Verge Motorcycles, says its cells will move into production as soon as this year.

Test results and the specifications Donut Lab is promoting

Industry scepticism largely stems from the company’s limited public track record in research, alongside the absence of published scientific data. Even so, Donut Lab has shared the outcomes of independent testing carried out by Finland’s leading state research and technology organisation (VTT Technical Research Centre of Finland). Those tests reportedly support the company’s headline figures: an energy density of 400 Wh/kg, a 5-minute charge time, a lifetime of up to 100,000 cycles, and operating tolerance from -30 to 100 °C. The batteries are also said to avoid rare-earth elements and do not use flammable liquid electrolytes.

What remains unproven, and why specialists remain cautious

Despite the test claims, several crucial points-such as the precise chemistry, achievable density in practical use, and real-world longevity-are still not independently established. During thermal testing, Donut Lab’s batteries reportedly ran into vacuum-sealing issues, raising concerns about the robustness of the underlying approach. Researchers and other experts also point out a well-known obstacle for solid-state designs: dendrite formation, where metallic filaments or cracks can develop and trigger short circuits.

China’s parallel progress in solid-state batteries

While Donut Lab says it is working to address the weaknesses, development elsewhere continues at pace-particularly in China. CATL has recently filed a patent for batteries it says can reach 500 Wh/kg, and it aims to begin small-scale production in 2027. Other Chinese firms, including FAW, have also said they are ready to integrate their batteries into electric vehicles.

Donut Lab maintains that “their technology represents a threat to major market players”. The company’s chief executive, Marko Lehtimäki, said resistance from the industry will only intensify, regardless of the evidence. Donut Lab has also announced a second battery version that it describes as more manufacturing-ready, with shipments to customers expected towards the end of the year.