In-depth investigation exposes Donut Lab’s solid-state battery as regular li-ion

Source: Electrek Image source: Electrek

Following a high-profile reveal in January at CES 2026 of a solid-state battery for electric motorcycles, the claims made by Donut Lab have been thoroughly investigated by science and engineering channel Ziroth. With input from over 20 independent battery experts, the investigation concludes with what amounts to definitive proof that the battery is in fact a lithium-ion cell.

Doubts about the veracity of the claims by Donut Lab – 400 Wh/kg, 100,000 charging cycles, and 5-minute charging – about the solid-state battery have been circulating for some time. A whistleblower complaint was made in April by Lauri Peltola, the former CCO of Nordic Nano, the manufacturing partner of Donut Lab. This complaint accused Donut Lab of “misleading the public with its claims, specifically on energy density, durability and production capacity.”

At an even earlier stage, Electrek’s Editor-in-Chief, Fred Lambert, interviewed Donut Lab CEO Marko Lehtimäki soon after the CES 2026 announcement, with a great deal of scepticism about the claims.

Independent testing from Finland’s VTT Technical Research Centre could not support the 400 Wh/kg energy density and 100,000-cycle life claims. Donut Lab undertook its own Technical Due Diligence (TDD) process, rather than seeking independent validation – a process described by Lauri Peltola as deeply inadequate, given the lack of battery chemistry expertise.

The companies behind the battery

The Ziroth investigation uncovers the relationship of companies behind the battery – none of which have specialised battery expertise. Donut Lab was created as a spin-off of the Finnish electric motorcycle brand, Verge Motorcycles. CT Coatings, a German company, was the technology provider; Nordic Nano the manufacturer; and Donut Lab the commercialiser. However, CT Coatings promised a screen-printed sodium-ion solid-state battery, but what it delivered was a lithium-ion pouch cell. It is also reported that Nordic Nano has never manufactured any battery cells.

The electrochemical evidence

A key part of the Ziroth investigation is the exploration of electrochemical evidence, with voltage curves and cell expansion data showing the tested cell to be lithium-ion. Over 20 independent battery experts were consulted, including Julian Zanau from the Fraunhofer Research Institute, Dr. Yahim San from Justus-Liebig University, Tom Bicha from Leona, and Dr. Yuo Hesca from Seinäjoki University of Applied Sciences. 

Electrek outlines the electrochemical evidence:

“There are two key pieces of evidence. First, the voltage curves from VTT testing match high-nickel lithium-ion cells (NCM chemistry). The cell sits at 3.7-3.8 volts at 50% state of charge — right where lithium-ion cells operate. Sodium-ion cells don’t go significantly past 3.5 volts at 50% SOC.

“The second piece of evidence is even more damning: VTT’s cell expansion data. When a battery charges, ions squeeze into the anode material, causing it to expand in a predictable pattern. A graphite anode produces a distinctive “kink” in the expansion curve around 50-70% state of charge, caused by how ions reorder themselves in graphite’s layered structure. The Donut Lab cell shows exactly that kink.

“This is critical because sodium ions are physically too large to fit into graphite layers. The graphite anode signature proves the cell uses lithium ions.”

The fundraising aspect

Donut Lab raised $25 million from over 1,300 shareholders, most of which are small investors – over 900 hold 50 or fewer shares, and many were gathered through a crowdfunding exercise on Finland’s Springvest platform, performed in 2023 for Verge Motorcycles. When the restructuring of Verge Motorcycles took place and the Donut Lab became a spin-off, the company’s valuation transformed from that of a struggling motorcycle brand, to being the parent company of a highly valued portfolio, based on the “miracle” battery. An investor letter from Lehtimäki spoke of “a potential return on investment of up to 10x in just 12 to 18 months.”

The Ziroth investigation argues that the process of presenting self-validated TDD in order to raise funds from inexpert investors was deliberately chosen, avoiding the more in-depth scrutiny that a venture capital investment firm would want to see.