Finnish startup Donut Lab has released independent test results showing its solid-state battery cell can charge extremely quickly. Commissioned by Finland's VTT Technical Research Centre, the tests demonstrated the cell reaching 80% charge in under five minutes at an 11C rate, with a full charge in under eight minutes.
However, battery experts express significant skepticism. The tests were conducted on a single pouch cell in a lab setting and do not address critical performance factors at the battery pack level. Major unanswered questions include the battery's long-term cycle life—Donut claims 100,000 cycles—and its behavior over many charging sessions in real-world conditions.
Experts also note the company has still not disclosed the fundamental chemistry of its cells, a key detail for validation. "Anyone who does not reveal the chemistry cannot be the real deal," said Professor Shirley Meng of the University of Chicago. The test results, while promising for fast-charging capability, omit data on energy density, discharge rates, and capacity retention over time.
Donut Lab plans to install its batteries in Verge Motorcycles' EVs this year. The company states it will release more independent test results in the coming weeks, which may address some of the open questions regarding chemistry and durability.