Joint expert investigation confirms: the so‑called “world’s first mass‑producible all‑solid‑state battery” is in fact a conventional lithium‑ion battery, raising suspicions of fraud in a roughly $25 million funding round.

The all-solid-state battery developed by Finnish startup Donut Lab—once hailed at the 2026 International Consumer Electronics Show (CES) as a “battery revolution” and widely covered by countless media outlets—has recently been officially debunked as a fraud by a consortium of battery researchers and more than 20 independent experts. The so‑called revolutionary all‑solid‑state product is, in essence, nothing more than an ordinary lithium‑ion battery. Industry insiders generally regard this incident as the most egregious “tech‑packaging” scam in the power‑battery sector in recent years, with the media drawing broad parallels to the Theranos scandal in the battery industry.

Event Recap: A “Battery Revolution” Sparked by CES

In January 2026, a Finnish startup called Donut Lab took to the stage at CES 2026, immediately sending shockwaves throughout the industry. According to its official website and on‑site presentations, the company’s self‑developed “world’s first all‑solid‑state battery ready for commercial mass production” has simultaneously redefined industry benchmarks in energy density, charging speed, cycle life, and cost.

In terms of energy density, the company claims its battery cells achieve an impressive 400 Wh/kg, nearly matching the top-tier performance of conventional ternary liquid‑state lithium batteries and certain semi‑solid‑state products. As for charging efficiency, the manufacturer states that it can replenish its charge in about five minutes—equivalent to a 12C ultra‑high‑rate charge. Even more astonishing, the battery is said to boast a cycle life of 100,000 cycles. At a typical usage rate of one charge every three days for a standard passenger vehicle, this battery could theoretically last for over eight centuries. Furthermore, the company asserts that the battery contains no lithium and no rare‑earth materials, while maintaining more than 99% of its capacity across an extreme temperature range from –30°C to above 100°C.

With these groundbreaking specifications, Donut Lab quickly emerged as one of the most closely watched battery companies at CES 2026, attracting more than 1,300 investors to its funding round and raising a total of approximately US$25 million (about RMB 170 million). At one point, the company’s valuation soared to US$1.25 billion.

Full of疑点: From a global sensation to widespread skepticism

In fact, even from the moment Donut Lab made its official announcement, the industry was rife with skepticism. In January, Yang Hongxin, Chairman of Svolt Energy, publicly stated that the battery described by Donut Lab simply does not exist in reality and that its technical specifications contain glaring inconsistencies: “No engineer with even a basic professional background would believe it to be genuine.”

Even greater doubts have emerged from Finland’s VTT Technical Research Centre, an independent third-party organization that has conducted five rounds of independent testing yet has consistently failed to validate two key performance metrics: an energy density of 400 Wh/kg and a cycle life of 100,000 cycles. Furthermore, according to a whistleblower letter from the former Chief Commercial Officer of Nordic Nano, this battery has never met its claimed technical specifications; the so‑called “world’s first mass‑produced all‑solid‑state battery” is, in fact, a technical claim that cannot be replicated.

The truth revealed: Voltage curves and swelling characteristics constitute key evidence.

Building on years of mounting suspicions, battery‑industry researcher Ziroth convened a comprehensive forensic investigation involving more than 20 independent battery experts, with scholars from prestigious institutions such as the Fraunhofer Institute and Justus Liebig University Gießen participating. The investigative team ultimately presented two irrefutable physicochemical lines of evidence, conclusively establishing the falsification.

The first piece of evidence comes from the voltage‑voltage curve provided by Finland’s National Technical Research Centre. The results show that, at 50% state of charge, the tested sample maintains a stable voltage between 3.7 and 3.8 volts, fully consistent with the typical electrochemical characteristics of high‑nickel ternary lithium‑ion batteries (nickel–cobalt–manganese system). By contrast, a sodium‑ion all‑solid‑state battery under the same state of charge exhibits a voltage that rarely exceeds 3.5 volts. More critically, if the battery truly contained no lithium, it would be impossible to detect the characteristic lithium‑ion voltage plateau in electrochemical testing.

The second piece of evidence is even more conclusive. The investigation team analyzed the battery’s swelling data during charging. In liquid‑electrolyte lithium‑ion batteries with graphite anodes, when the state of charge reaches the 50%–70% range, the swelling curve exhibits a very distinct “inflection point,” caused by lithium ions intercalating into the layered structure of graphite. By contrast, sodium ions are too large to intercalate into graphite at all, so this characteristic physical change does not occur in solid‑state electrolyte systems. The Donut Lab sample’s swelling curve precisely displays this hallmark inflection point. To illustrate, the team offered the following analogy: “It’s as if we had obtained a fingerprint with some noise and also captured a clear frontal photo of the suspect—both match perfectly.” Based on comprehensive calculations, the battery’s actual energy density is approximately 298 Wh/kg, which is only about the typical level of a high‑quality conventional ternary lithium battery and falls far short of its claimed 400 Wh/kg.

A Deeper Scam: A Technological Shell Without a Core

As the investigation deepened, a more systematic tracing of the supply chain came to light. The inquiry revealed that the so‑called all‑solid‑state batteries used by Donut Lab actually derive their technology from a German company called CT Coatings. This firm holds an extremely broad portfolio of patents; aside from a handful of battery‑related applications, its patent filings also cover entirely unrelated areas such as screen‑printed paving bricks, menu holders, and warning triangles. In fact, what CT Coatings supplied to Donut Lab was a run‑of‑the‑mill lithium‑ion pouch cell—commonplace on the market—not any novel all‑solid‑state product. Meanwhile, Nordic Nano, the contract manufacturer that produced these samples, has never even manufactured a single solid‑state battery cell.

During commercial collaborations and fundraising, the parties involved have relied on stringent non‑disclosure agreements to conceal technical details at every level, leaving external institutions and the media unable to obtain fully transparent verification reports through official channels. According to leaked internal company emails, Donut Lab repeatedly requested formal technical specifications from CT Coatings but never received a substantive response. Yet, in the absence of independent external validation and meaningful technical evidence, Donut Lab unilaterally completed its entire technical due diligence. The company’s CEO even pledged in a letter to investors “up to tenfold returns within 12 to 18 months,” urging them that “it’s still not too late to get in now.”

In a broader review of corporate information and commercial disclosures, the investigative team likewise uncovered evidence of falsification. Donut Lab had publicly announced that, by the first quarter of 2026, it would deliver production‑grade vehicles equipped with its solid‑state battery to a customer—the Finnish electric motorcycle company Verge Motorcycles. However, leaked internal videos reveal that the initial “production vehicles” unveiled to the public were in fact only prototype units intended to optimize the manufacturing process, not the final mass‑produced models destined for consumers. In a subsequent interview with Finnish media, the company’s CEO, Lehtimaki, also acknowledged that the battery cells touted as featuring a 400 Wh/kg solid‑state battery were never actually installed in any vehicle, and that the samples previously sent to VTT for testing “were not even the final delivery version.”

Industry Consequences: A Global Tech Scandal Is About to Face Legal Accountability

This wave of technological fraud, widely compared by the media to a battery‑industry version of the Theranos scandal, has begun to trigger a chain reaction across the global battery sector and among investors. According to an exclusive report by the leading battery‑industry publication Electrek, Ziroth’s investigation has uncovered numerous falsehoods fabricated by Donut Lab regarding its manufacturing and delivery capabilities—most notably, that it lacks the technical capacity to execute even a single step required for mass‑producing solid‑state batteries.

Even more troubling, among the more than 1,300 investors in total, over 900 held no more than 50 shares each, with individual investments ranging from roughly $3,000 to $23,000—almost all of them small- and medium-sized retail investors. The investigation concludes that the company deliberately opted for a fundraising approach that substitutes self‑certification for independent third‑party technical review, which in essence amounts to a malicious practice aimed at sidestepping the rigorous due‑diligence procedures typically imposed by venture capital firms.

To date, Finland’s financial regulatory authorities and criminal investigation agencies have formally launched an investigation. This financial fraud case in the battery sector may involve multiple serious violations, including false advertising and the falsification of financing documents.

Industry Reflection: The Industrialization of All-Solid-State Batteries Requires Discarding the “Technology Bubble”

As the dust settles on the tech‑driven hype, the entire new‑energy sector is now earnestly scrutinizing its own underlying impatience and short‑termism. The Donut Lab saga managed to spark months of global attention precisely because it capitalized on the industry’s rampant capital frenzy and pervasive information vacuum surrounding all‑solid‑state batteries.

A representative from the China Automotive Power Battery Industry Innovation Alliance pointed out that truly all‑solid‑state batteries still face key challenges, including high interfacial resistance at the solid–solid interface, difficulties in accommodating volume changes, and immature manufacturing processes. High‑performance products with higher energy density and longer cycle life remain in the pilot‑scale validation stage. CATL Chairman Zeng Yuqun explicitly stated that the current technological and manufacturing maturity of all‑solid‑state batteries stands at only Level 4 (on a nine‑level scale), leaving a substantial development gap before large‑scale production at the GWh level can be achieved. Toyota, too, maintains a cautious stance on the timeline for the commercial deployment of all‑solid‑state batteries, with mass production not expected before 2030.

Meanwhile, the recent Donut Lab fraud incident is expected to accelerate the establishment of a global verification system for power‑battery performance standards. Industry experts recommend that the battery sector should develop a rigorous, multi‑dimensional third‑party testing and certification framework—covering voltage profiles, swelling characteristics, interfacial impedance, and more—and subject any new product claiming “disruptive breakthroughs” to reproducible, verifiable engineering‑level validation. Only by making genuine, independently replicable electrochemical measurement data publicly available for scrutiny can we fundamentally curb the spread of false claims in the new‑energy arena.