Earlier this year, a relatively unknown Finnish startup made a shocking announcement: it had finally solved solid-state batteries.

Not only that, but Don’t Lab, a Verge Motorcycles spin-off, said its solid-state battery — long considered the “holy grail of batteries” for their high-density, durable, fast-charging capabilities — will go into production later this year.

Battery experts were understandably skeptical. After all, solid-state batteries are one of those technologies, along with artificial general intelligence and hyperloop, that look two years away. And while most legitimate efforts in this field – whether academic or commercial – are associated with published research or recognizable names, DonutLab seems to have emerged out of nowhere, with no known researcher or prior presence. This lack of traceability immediately raised concerns about the startup’s credibility.

“I can’t say they haven’t,” said Eric Wachsman, director of the Maryland Energy Innovation Institute and an expert on solid-state batteries and solid-oxide fuel cells. “All I can say is that they haven’t demonstrated that they have.”

The skepticism is warranted, especially when you consider how many other people are chasing the solid state dream. Are we really to believe that this obscure startup has beaten Toyota, Stellantis and the entire nation of China to the punch? The odds were against him.

Don’t Lab anticipates this skepticism, launching a website last February called idonutbelieve.com Which would serve as a platform to publish independent tests confirming that his solid-state battery was indeed real and brilliant. Over the course of several weeks, the startup published third-party results from Finland’s state-run VTT Technical Research Center that proved its battery was what it said it was: a fast-charging, high-energy-density solid-state battery that wasn’t actually a supercapacitor in disguise.

“The resistance won’t go away when we present the evidence,” Donut Lab CEO and cofounder Marko Lehtemecki said in a video. “It will only intensify as this new technology threatens established players in the industry.”

But Donut Lab is still hiding the ball on some key information. At CES in January, the startup said its solid-state battery has an energy density of 400Wh per kilogram, nearly double that of typical lithium iron phosphate (LFP) batteries in production. Not only that, but it could be fully charged in five minutes, had a virtually unlimited lifespan of 100,000 charging cycles, was unaffected by heat and cold (minus 30 degrees Celsius and 100C), and contained no rare earth elements, precious metals, or flammable liquid electrolytes.

Much of it is unconfirmed. Even after posting five independent test reports from VTT, the startup has yet to demonstrate the three most important metrics: chemistry, density, and cycle life claims.

The stakes are incredibly high. Imagine an electric vehicle that could travel 700-800 miles on a single charge, and was not in danger of bursting into flames because the flammable electrolytes were replaced with solid materials.

In lithium-ion batteries, the movement of liquid electrolytes generates heat, and under certain conditions, this can slip into a “thermal runaway” effect that can result in a fire. In comparison, solid-state batteries make it safer to quickly draw power from (or add it back to) the battery, meaning you could theoretically charge an EV faster. It could also mean that structurally, less space has to be allocated to temperature control, which could allow companies to squeeze more battery cells into the same size pack.

After reviewing Donut Battery’s tests, Wachsman said there are still significant concerns. During the extreme heat test, for example, the pouch surrounding the donut battery lost its vacuum seal. Gas production inside batteries – due to processes such as electrolyte decomposition or oxygen release – can cause the battery pouch to swell and rupture. But without knowing the exact cell chemistry, it’s hard to say how significant this failure is in a donut battery.

Putting the donut battery aside for a moment, solid-state batteries have struggled to graduate from the laboratory to the assembly line due to well-documented problems. These batteries often suffer from the formation of metal cracks called dendrites that cause them to short circuit. Think of them like cracks in a sidewalk when a tree root grows down.

Dendrites have been a thorn in the side of battery manufacturers since the 1970s. One reason lithium-ion batteries have become ubiquitous while other approaches have stalled is that their commonly used graphite anodes are less susceptible to dendrite formation.

But new discoveries may help engineers finally overcome these obstacles. Recently, a research team at MIT I published a study The nature He found that chemical reactions caused by high electrical currents that weaken the electrolyte also make dendrites more susceptible to growth. This is why simply developing stronger electrolytes has not solved the decades-old dendrite problem. And it may point to the importance of developing more chemically stable materials to fulfill the promise of solid-state batteries.

Progress is already being made – where else? – Last month in China, CATL, which controls about 40 percent of the global battery market, filed a patent application for solid-state batteries with a reported 500Wh energy density. According to Carnews ChinaThe battery maker is already planning small-scale production in 2027. But automotive-grade cells won’t be ready until the end of the decade.

Other Chinese companies are leading the way. Automaker FAW said recently that its “liquid-solid-state” lithium-rich manganese cell with 500Wh/kg was ready for vehicle integration.

China is already laying the groundwork for mass production by the end of the decade, by which time it hopes the technology will be mature. And why wouldn’t it? It is a country that has taken EVs and battery development seriously for many years, allowing it to corner the market on much of the world’s supply.

Different companies are taking different approaches. For example, Honda is committed to Sulfur-based electrolytes Despite emerging alternatives. Last October, Toyota announced. “The world’s first practical use of all-solid-state batteries in BEVs” by 2027 or 2028. And Mercedes, using a prototype battery from startup Factorial, managed to get an electric EQS ​​sedan 749 miles of real-world range.

“Companies probably have a ways to go,” said Alevtina Smirnova, director of the NSF Industry-University Cooperative Research Center for Solid-State Electric Power Storage. “Because what’s happening in China now has no comparison to what’s happening in America.”

For its part, Donut Lab is undeterred by skeptics about its claims. On April 1st, Lehtimäki posted a new video addressing some of the controversy surrounding his solid state batteries. He also revealed that DonutLab has built a second, more production-ready version of its battery that will begin shipping to customers later this year.

There was an important admission: The widely discussed “100,000 cycles” figure was a design goal, he said, not an empirically verified result. Actual testing is done in short cycles, with estimates based on known variables such as charge rate, temperature, and usage conditions.

He then hinted at another near-term project: Donut Lab’s latest chili drop, including a bucket hat covered in “tin foil.”