A high-profile investigation by battery researcher Ryan, widely known as Ziroth, has concluded that the much-hyped solid-state battery technology from Donut Lab is a standard lithium-ion cell. The detailed report, which surfaced within the last 24 hours, undermines the startup’s claims of a revolutionary, lithium-free energy storage device.
The investigation comes at a time of heightened scrutiny in the energy sector, as global investors struggle to separate genuine innovation from potentially fraudulent clean-tech ventures. Donut Lab had previously secured $25 million in funding from over 1,300 small investors based on promises of a cell with 400 Wh/kg energy density and rapid, safe operation across extreme temperatures.
Electrochemical Evidence of Fraud
Ziroth’s analysis utilized data from more than 20 independent battery experts to verify the true chemistry of the device. The investigation revealed that the test cell operated at 3.7-3.8 volts at 50% state of charge, a voltage curve consistent with common lithium-ion NMC chemistry rather than the sodium-ion or solid-state alternatives touted by the company.
Most tellingly, the battery displayed a unique physical signature during testing. According to independent testing observations, the cell expansion data showed a specific kink between 50% and 70% state of charge. This physical trait is characteristic of graphite anodes, which are used in lithium-ion batteries. Sodium ions are too large to intercalate into graphite, essentially disproving the claim that the device was lithium-free.
Broader Industry and Legal Fallout
The discovery is the culmination of months of skepticism following the company’s debut at CES 2026. Industry leaders, including Donut Lab critics from major battery manufacturers, had questioned the lack of verifiable data provided by the startup. The company reportedly utilized a complex structure of shell companies and strict non-disclosure agreements to obscure that their cells were supplied by a third-party firm, CT Coatings.
Legal actions are currently underway. A criminal complaint was filed in April 2026 by the chief commercial officer of Nordic Nano, citing unachieved product specifications. Additionally, the company’s financial integrity has been called into question, as auditors at PwC reported they could not complete the 2024 financial audit due to missing records regarding inventory and sales.