Donut Lab Battery Works at 100° Celsius, Proves More Skeptics Wrong

Support CleanTechnica’s work through a Substack subscription or on Stripe.

Speculation that the Donut Lab battery is not real are diminishing as independent lab data shows 100° Celsius performance. Speculation that the battery may be lithium run into difficulty explaining how a battery can work at 100° Celsius. In the independent tests, the thin membrane surrounding the pouch breached. If the contents were a standard lithium-ion with liquid electrolyte, there would have been significant outgassing and the organic electrolyte would have caught fire. 

The Battery Is Real

Attention is now focused on what it could be, and the speculation continues. Once again, there are so many different stories, and the quality of analysis on social media has a wide range. It is time to admit the truth. Donut Lab is not lying. It is not a liquid electrolyte. It is solid state. It is time to listen to what Donut Lab says.

More can be learned from Donut Lab than by speculation. As I said before, we can make inferences based on what we know is fact. We cannot make inferences based on what we do not know or have never experienced before. The Donut Lab high-temperature battery tests place us in new territory, where no other intercalated battery has been before. That is one reason for resistance and disbelief. The reaction from other battery competitors has quieted and has turned from “if we can’t do it, you cannot either” to “if we cannot do it, how on Earth did they do it?” The latter is less audible as well.

The time for speculation is over. It does work at 100° Celsius. It does charge at 11C. Donut Lab battery performance is extraordinary. There is more to be gained by listening to what Donut Lab says than by speculation. Donut Lab is telling the truth. Yes, the claims are not full engineering specifications including all conditions and limits. Claims like this are normal for this stage of development. In the tests, Donut Lab’s battery performed well at 100°C and retained full function when returned to room temperatures. There are more questions. There are more weeks of independent testing to come, results revealed once a week. Patience is the order of the day. Now a few myths must be laid to rest.

It Is Not A Production Lithium-Ion Battery

It does not contain a liquid organic electrolyte.

How do we know the battery does not contain liquid organic electrolyte? During tests, the thin pouch enclosure was breached. Donut Lab stated it is a solid electrolyte, and any NMC battery in production today (using a liquid organic electrolyte) exposed to 100° temperatures that breached its package would have caught fire. We know that Donut Lab did its own tests and sent its batteries to independent labs before this round of testing. The CTO is not gambling. 

Does it have to be a lithium battery? Not really. Battery cell maximum voltage can be altered by doping, adding a small amount of another substance to a chemistry.

“Doping is a potent and often used strategy to modify properties of active electrode materials in advanced electrochemical batteries. There are several factors by which doping changes properties critically affecting battery performance, most notably the voltage.”

The maximum voltage can be raised and charge curves changed. It is possible that different chemistry charge curves could look alike and yet follow electrochemistry rules. The fact that similar chemistry charge curve voltage is unusual is not proof it cannot happen. Donut Lab is telling the truth. It does not contain a liquid electrolyte and it is not a production NMC lithium-ion battery. I think it is time to stop doubting and start listening.

The Sunwoda NMC Battery Is Not A Counterargument

There is an argument made that the Sunwoda battery proves that an NMC battery could survive 11C testing. It could at low temperatures, but not at 90C and not with a ruptured pouch. Further, the Sunwoda battery attains 11C by sacrificing energy density. The energy density is only 102 Wh/kg. It shaves the cathode and anode down to the thinnest possible width to reduce the distance ions need to travel. This increases ion flow and reduces internal resistance, resulting in faster charge. It does not meet the criteria of a contradiction to Donut Lab’s claims. It is an outlier and not representative of most standard NMC batteries. None of this changes the fact that no NMC or other production lithium battery could duplicate the tested performance of Donut Lab’s battery. There are no intercalating lithium batteries that duplicate the performance over the range of temperature used, from -30°C to 100°C.

What Did Donut Lab Say? It Is Not Lithium

We do not have to search far for that. Marko answered to an interviewer.

Interviewer: Operating in whatever temperature…

Marko: and also the environmental and supply chain concerns that people always had for electric vehicles…

Interviewer: lithium, cobalt… whatever…

Marko: All of that is gone.

And we know more from CTO Ville Piipo who also says this is “non-lithium” at about 26:26.

He also says: “We’ve been doing like third party analysis or validations in recent years, but that is more for our own sanity checks…”

Knowing that Donut Lab already measured the batteries and had prior third party testing, there is little risk in further independent tests made public. They already know what the results will be. It is only us, the viewers, that have any suspense in awaiting the outcome. That leaves viewers scratching their heads, guessing what the battery is.

Why Is Solid State So Difficult?

In a nutshell, the problem with solid-state batteries has been keeping solid materials in contact despite expansion and contraction. The cathode, anode, and electrolyte are all solids. They are powders composed of small grains. Contact between them is limited, unlike with a liquid electrolyte. There can be voids at the boundaries. Up until now, solid-state batteries have required very high pressures to maintain good contact and conductivity. 

Donut Lab’s battery does not require heavy pressure to maintain performance. What are possible solutions? An electrolyte can begin as a liquid and get pressed to fill voids, and then be secured in place by becoming a solid, or semi solid like a soft glue or polymer. When that sets, a solid is in place that meets the requirements. For now, the solid electrolyte is unknown.

What Else Do We Know?

Another battery type that matches some of the characteristics of Donut Lab’s solid-state battery is sodium-ion. Low- and high-temperature performance looks similar. But at high temperatures, Donut Lab’s battery goes even further. The safety of both is high. The cost of both is low. Both are made of commonly available materials. Neither contains lithium. Sodium-ion batteries have high cycle life, and Natron’s sodium chemistry was claimed to have a cycle life of 50,000 cycles. Donut Lab’s battery has an energy density of 400 Wh/kg, while liquid electrolyte sodium-ion batteries have an energy density of 175 Wh/kg. Sodium-on is also capable of C rates of 5. The differences are the higher temperature, higher energy density, faster charging, and more extreme cycle life. Could solid-state render a sodium-ion battery with greater energy density and fit the final piece of the puzzle? We know there are some cathode materials used with sodium-ion, like TAQ, that allow high energy densities.

“Altogether, these allow the construction of SIB cells built from an affordable, sustainable organic small molecule, which provide a cathode energy density of 472 Wh kg–1 electrode when charging/discharging in 90 s and a top specific power of 31.6 kW kg–1 electrode.”

“These figures underscore the potential of this technology to compete with and eventually surpass existing lithium-ion batteries in various applications.”

This does not prove Donut Lab’s batteries are sodium-ion. It does suggest that there are pathways to performance similar to them.