Technology
Donut Lab publishes lab test showing 409 Wh/kg battery energy density amid missed production timeline
A Finnish research centre validated the startup's energy density figure, though tests leave questions about solid-state chemistry and durability unanswered.
The short version
- Donut Lab published results from Finland's VTT Technical Research Centre showing a prototype cell reached 409.3 Wh/kg and 804.7 Wh/L.
- The results follow a missed target to have the solid-state batteries powering production Verge Motorcycles by the end of Q1 2026.
- The lab test evaluated energy density across only two cycles and did not independently verify the cell's solid-state chemistry or long-term cycle life.
Key facts
- Testing by Finland's VTT Technical Research Centre showed a Donut Lab 'V1.5' cell (designated DL6) achieved an energy density of 409.3 Wh/kg and 804.7 Wh/L during a 0.1C discharge across a 2.3–4.25V range at 25°C.[Electrek]
- Donut Lab previously stated at CES in January that its battery was ready for OEM vehicle manufacturing and scheduled for commercial delivery in Verge Motorcycles by Q1 2026, a milestone that was not met.[Electrek]
- The VTT evaluation lasted for only two capacity cycles and did not make an independent determination regarding whether the battery utilizes solid-state chemistry.[Electrek]
- Donut Lab CEO Marko Lehtimäki previously acknowledged in Finnish media that the cell subjected to testing is not the exact version planned for delivery to customers.[Electrek]
- A criminal complaint filed in April by Lauri Peltola, the former commercial chief of manufacturing partner Nordic Nano, alleged that earlier tested cells were older generations abandoned by the company, allegations Donut Lab denies.[Electrek]
What remains uncertain
- It remains unverified whether Donut Lab's battery relies on solid-state electrolytes or if it can deliver the company's claimed lifespan of up to 100,000 cycles under real-world operating conditions.[Electrek]
- The timeline for when production electric vehicles equipped with the battery will reach consumers remains unknown.[Electrek]