Posted on 02/25/2026 8:02:48 AM PST by GenXPolymath
Donut Lab commissioned VTT to validate its bold solid-state claims, and the results show near-full capacity retention even after ultra-fast charging...
Rapid charging under test
VTT Technical Research Centre ran the tests in what engineers described as a worst-case scenario.
The lab did not use active temperature controls. It also let the cell’s heat rise freely at high charging rates.
Experts measured performance using C-rates, where 1C equals a one-hour charge from empty to full.
Under that scale, 5C roughly equals a 12-minute charge, and 11C is about a five- to six-minute charge.
The process began with a standard discharge test at 1C. Rapid charging followed at 5C and 11C under both cooling configurations.
At 5C, the battery held up well, reaching 80% state of charge in about 9.5 minutes and 100% in just over 12 minutes.
After discharge, the cell retained all its stored energy. These results align with the five-minute charge claim the company previously announced.
Extreme speeds, full capacity
Donut Lab then pushed the cell to even higher charging rates. At an 11C rate, the battery reached 80% charge in 4.5 minutes. It hit full capacity in just over seven minutes.
When discharged after this rapid charge, the cell retained between 98.4% and 99.6% of the energy it had stored.
These figures show the battery’s ability to handle intense power input without huge losses.
Unlike many solid-state concepts being developed in labs, Donut Lab’s design performed these tests without requiring active cooling systems.
It also did not need unusual pressure or compressive force on the cell to work effectively.
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The numbers and data speaks for itself.
This kind of breakthrough is not just about EVs the modern world simply doesn't exist without the energy density of the lithium ion battery. It's in everything smartphones, tablets, laptops, medical devices, anything that's portable that requires an electric current simply put modern society doesn't exist without the energy density of lithium type cells. These solid state cells have the same density or more, but can charge in a fraction of the amount of time even if never adopted at the EV level these will fundamentally change consumer devices.
What's equally impressive is the lack of the need for active cooking even at a record 11C rate and no high pressure structural bindings that liquid filled cells need.
Cells like these are the next generation of cells for the trillion dollar consumer battery market. Smartphones that charge in 4 min or under , same for laptops or tablets. Drones, EV scooters and Ebikes too.
The 21st century is gonna be lit y'all.
but it takes what ? a hundred times the power that the slow chargers do ?
When does Donut Lab go public?
I really like it when science is done well.
Not to hijack the thread, but it’s my opinion that topics like Climate Change and also Evolution are simply not approached like other scientific areas. Observable? Repeatable? Testable? Falsifiable? I figure people can believe whatever they want to believe. If it’s an article of religious faith that mankind is changing the climate or that all life sprang up randomly from nothing, then it’s not my place to attack that faith. But those particular bits of “science” cannot ever be handled the way Donut Lab just got verification from VTT.
Kudos to Donut Lab and to VTT.
THIS!
Not equal to LFP or Li-Ion double.
“The Finnish startup claims 400 Wh/kg energy density, under 10-minute charging”
LFP is 160wh/kg
LI NMC is 220wh/kg
https://interestingengineering.com/energy/donut-lab-test-result-solid-state-battery
I hope the IPO soon.
Why do they not give the time for 100% charge? Does the last 20% take far longer time? Always question why they report in this manner, because there is a reason that they report it as they do.
They have already been debunked as very likely a scam.
They bought a company who claimed to have developed the technology.
It looks like they invented that story so someone would buy them.
The physics is all wrong on the charging cycle they are reporting.
The guy was going over VTT's results, and he said there was a lot of troubling things in there, and it looked like Donut Labs was misleading people.
He said the battery looked like a lithium battery based on it's power curve, power density, and other data.
And there was no proof presented that it was actually solid state.
And burn out the battery after 5 charges?
Let’s plug them all in at the same time and see what happens.
“but it takes what ? a hundred times the power that the slow chargers do ?”
No by definition 11C is eleven times the 1 hour charge rate.
DC to DC losses are 5-8% so 11.08 times the one hour current.
For a typical smartphone with a 5 amp hour battery that would be 11.08 times that so 55.4 amps at 3.7 volts to 11C charge a typical smart phone. That’s 204 watts.
The current fastest USB-C charging standard is USB PD 3.1 Extended Power Range (EPR), which delivers up to 240W (48V/5amps)
So the current standard could do it now.
What did the temperature of the battery hit while charging at such high rates? Would that severely lessen the life of the battery? Increase chance of fire?
Can someone explain something to me? I thought when a battery “discharges” that means it gives up its electrical energy. So how do these battery maintain 80-90 percent of their energy after “discharge?” Please enlighten me if I read it incorrectly.
As of February 2026, the “Donut Lab” solid-state battery has been widely accused by industry experts and battery manufacturers of being a scam or a “hoax” due to improbable performance claims and a lack of transparent, independent verification.
The Finnish company, linked to Verge Motorcycles, claimed at CES 2026 to have developed a “miracle” solid-state battery, but experts have highlighted numerous red flags surrounding the announcement.
Key Evidence and Red Flags
Unrealistic Performance Metrics: Donut Lab claims its batteries feature 400 Wh/kg energy density, 5-minute charge times (0-80% in 4.5 minutes), and a lifespan of 100,000 cycles. These figures far exceed current technology and are considered impossible to achieve simultaneously.
“Empty Case” at CES: Reports indicate that during the reveal, the company did not showcase a working prototype but rather empty battery cases.
Contradictory Data: Yang Hongxin, chairman of Chinese battery maker Svolt, labeled the claims a “scam,” stating that the parameters are contradictory and that such a battery does not exist in the world.
Lack of Peer Review: There have been no published scientific papers or patent disclosures related to their claimed battery chemistry.
Suspicious Test Results: Initial third-party test results (VTT) showed that while the cell could fast-charge, it behaved more like a high-performance lithium-ion cell or a supercapacitor under extreme stress, rather than a breakthrough solid-state battery.
Questionable Background: The company has very little history (founded ~2024) and minimal technical staff compared to industry giants, prompting comparisons to the Theranos fraud case.
“Why do they not give the time for 100% charge? Does the last 20% take far longer time? Always question why they report in this manner, because there is a reason that they report it as they do.”
Because lithium charges to 80% as the industry standard to save cycle lifetimes you smart phone if this a good one should stop at 80% every time.
Also batteries slowdown again to.improve cycle life from 80 to 100%
Both my expensive Samsung do this by default and so does my tablets and laptops they all use NMC cells so 80% is the tl� end and you don’t below 20% either.
I just watched the 8 min long test it looks like a typical power curve for lithium chemistry. The kinetics are set by the ion size lithium being smaller than sodium for example. Which CATL has got to do 5C charges with the larger sodium ion radius.
VTT has no reason to lie they are the independent tester. This is how science is done you hand the device to a third party and day break it if you can.
Every major player is doing a solid state cell, BYD,CATL,Toyota,Nissan,Benz,Panasonic the list is well everyone it’s when not if.
Watch the video in the article it goes into that.
They passively cooled they say that via conduction they even took half the passive cooling away
Yes after fast charging at 11C they were able to get back out of it 98% -99% of what they put in they lost 2% to heat and other kinetics.
The whole point of independent testing is to well test it. Show what a packaged device or cell can do on a test rig it’s not rocket science you plug it in establish the conditions and let it rip.
They don’t list the max temp but it was within its operating window or it would’ve failed or at the least shown huge resistive loses and only returned a fraction of what it was charged with.
Not much to mess up in a solid state cell it’s either nanoglass, ceramics or polymer as the separators/”electrolyte” the anode and cathode in Li is already solids even in liquid electrolyte cells.
I saw that video as well.
“Why do they not give the time for 100% charge? “
Uh, they do ...
“Can someone explain something to me? I thought when a battery “discharges” that means it gives up its electrical energy. So how do these battery maintain 80-90 percent of their energy after “discharge?” Please enlighten me if I read it incorrectly.”
I had to read that twice. They are stating the discharge energy.
Of course, when discharged, it retains little energy.
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