Donut Lab acquires Nordic Nano Group as Siilasmaa steps back to observer role
What's the deal? Finnish battery startup Donut Lab has completed its acquisition of Nordic NanoDealroom has a profile for this one. Try Dealroom → Group, buying the company's entire share capital. The companies did not disclose the deal's value.
What do they do? Nordic NanoDealroom has a profile for this one. Try Dealroom → develops environmentally friendly nanotechnology for solar energy, energy storage, and hydrogen production. Donut Lab builds motor, battery, control, and software technologies, and had already invested in Nordic NanoDealroom has a profile for this one. Try Dealroom → in July 2025.
What's the endgame? The acquisition brings all of Nordic Nano's solar intellectual property and expertise into the same group as Donut Lab's core technologies. "We believe solar technology has an important role in Donut Lab's next phase, which we have planned for a long time," chief executive officer Marko Lehtimäki said (translated from Finnish).
The hires: Nordic Nano founders Esa Parjanen and Jarkko Aro join Donut Lab's board. Aro has started as industrialisation director and Parjanen as business development director, while Nordic Nano's lead researcher Bela Bhuskute becomes Donut Lab's lead researcher.
Meanwhile , technology figure Risto Siilasmaa has moved from Donut Lab's board to an observer role and continues as an adviser. "We are grateful that Siilasmaa's experience and advice remain available to our company," Lehtimäki said. He has also invested in Donut Lab.
What could go wrong? Donut Lab drew scrutiny early this year over claims of a mass-production-ready solid-state battery it said would outperform current cells. The claims met scepticism, and a video series has not eased doubts.
In April 2026, former Nordic Nano commercial director Lauri Peltola said he filed a criminal complaint accusing the company of misleading communication and empty promises. Donut Lab and Nordic Nano denied the allegations, rejecting claims of any crime or misleading investors.
The signal: The deal folds a former partner and its solar expertise into Donut Lab as it pushes into new technology areas and markets — even as its headline battery claims remain unproven.
Read more: Kauppalehti
Image credit: Generated with Gemini
