Donut Lab claims solid-state batteries will reach production this year, but experts remain sceptical

Startup says batteries will reach production this year, but experts question part of the claimed performance

Finnish startup Donut Lab has announced what it describes as a breakthrough in solid-state batteries - often called the “holy grail” of battery technology because of their high energy density, long service life and ability to charge rapidly. Donut Lab, a spin-off from Verge Motorcycles, says its batteries will move into production as early as this year.

Test results and headline specifications for Donut Lab solid-state batteries

Doubts among specialists stem from the company’s lack of a well-known research track record and the absence of published scientific data. Even so, Donut Lab has released results from independent testing carried out by Finland’s leading state research and technology organisation (VTT Technical Research Centre of Finland). Those tests reportedly confirmed the figures Donut Lab has been promoting: an energy density of 400 Wh/kg, 5-minute charging, a lifespan of up to 100,000 cycles, and tolerance of temperatures from -30 to 100 °C. The batteries are also said to contain no rare-earth elements and no flammable liquid electrolytes.

What remains unproven

Despite the published test summary, the most important parameters - including the chemistry, energy density and service life - are still not fully evidenced in a way that convinces critics. During thermal testing of Donut Lab’s batteries, issues were observed with vacuum sealing, raising concerns about the technology’s reliability.

Researchers also point out that solid-state batteries continue to face the dendrite problem: metallic growths or cracks that can lead to short circuits.

Competition: China’s solid-state battery push

While Donut Lab says it is still working to address the shortcomings, progress elsewhere is moving quickly, particularly in China. CATL has recently filed a patent for batteries with an energy density of 500 Wh/kg and intends to begin small-scale production in 2027. Other Chinese companies, including FAW, have likewise stated they are ready to integrate their batteries into electric vehicles.

Donut Lab’s stance and next version

Donut Lab maintains that “their technology is a threat to major market players”. Chief Executive Officer Marko Lehtimäki said that resistance from within the industry will only grow, despite the evidence.

The company has also announced a second version of the battery that it says is more production-ready, with deliveries to customers scheduled to begin towards the end of the year.