Donut Lab alleged Solid State Battery launched at CES 2026

[Marco]

From all the definitions I can find, they all talk about "primary operating mechanism". So if the supercap is 2% chemical and 98% cap, then it's a cap.

Papers about hybrids are generally capacitive cathode, chemical anode. So 50/50.

[Randy222]

From all the definitions I can find, they all talk about "primary operating mechanism". So if the supercap is 2% chemical and 98% cap, then it's a cap.

Papers about hybrids are generally capacitive cathode, chemical anode. So 50/50.

Ok, in that case, it's neither. It's a hybrid.

But, hybrid configurations can reach energy densities of around 89.6 Wh/kg and power densities of up to 16 kW/kg.

Mr Donut says the thingy is ~500Wh/kg ? So it's not a hybrid?

Did I miss something?

[SteveThackery]

Given the size and density of the item, how could it not be a supercap? Can an alkaline-like or Li batt be made to that size & density?

May I ask what you mean by "density"? Do you mean the electrical capacity per kilogram (or possibly per unit volume)?

If so, I thought supercaps were nowhere close to the energy density of a lithium battery. Is that wrong?

Another thing: if the performance is as good as claimed, does it matter whether it is a supercap, or a solid state battery, or a normal lithium battery?

Sor for the basic questions - I have zero expertise in this area.

[thm_w]

But, hybrid configurations can reach energy densities of around 89.6 Wh/kg and power densities of up to 16 kW/kg.

Mr Donut says the thingy is ~500Wh/kg ? So it's not a hybrid?

Did I miss something?

- 400Wh/kg was claimed, not 500.
- 150-244Wh/kg is seen for hybrid supercaps in the lab: https://pubs.acs.org/doi/10.1021/acs.energyfuels.4c02984

[rteodor]

Maybe I am missing something so may I ask the audience what is the capacitance of existing supercapacitors and what is their voltage rating.

A little mind exercise: what would be the capacitance of a supercapacitor to match the energy storage of a 22.5Ah mystery cell ?
The cell energy capacity would be: 4.2V (nominal) * 22.5Ah * 3600 = 340.2 KJ.
A supercap charged at nominal voltage would have to be: 2 * 340.2 KJ / (4.2 V^2) = 38.571 kF (kilo Farad)!
Charged at 100V ---> 68.04 F.
Charged at 1kV ---> 0.6804 F.

Do such supercapacitors in the range of hundreds of thousands of Farad even exist rated at 4V ? And if they do, what is their physical size and weight ?
In the much spoken video we are shown a 4V cell. Any comment ?
---
Later edit: redo the numbers with a rough estimate of the cell shown in the video: 270A * 5 minutes / 3600 = 22.5Ah.

[Stray Electron]

Thread drift "Я" us!

At a certain point its not drift, its conspiracy and anti-EV nutters shitting on good quality technical threads.

  You forgot to mention the free-energy nutters, there are more than a few of them on this forum too.

[Stray Electron]

Maybe I am missing something so may I ask the audience what is the capacitance of existing supercapacitors and what is their voltage rating.

A little mind exercise: what would be the capacitance of a supercapacitor to match the energy storage of a 100Ah LFP cell ?
The cell energy capacity would be: 3.29V (nominal) * 100Ah * 3600 = 1.1844 MJ.
A supercap charged at nominal voltage would have to be: 2 * 1.1844 MJ / (3.29 V^2) = 218.844 kF (kilo Farad)!
Charged at 100V ---> 663.264 F.
Charged at 1kV ---> 2.3688 F.

Do such supercapacitors in the range of hundreds of thousands of Farad even exist rated at 4V ? And if they do, what is their physical size and weight ?
In the much spoken video we are shown a 4V cell. Any comment ?

   I don't know, but since we're already off topic and talking about super caps I'd like to ask this: What is the near term possibility of developing super caps with more than a ~2.7 volts per cell?

    Note that ~ is there for a reason! I see no reason to argue about if the present limit is 2.4 volts, 2.7 volts, 3.2 volts or any other minor difference.  I'm asking about a significant voltage increase.

[Randy222]

Given the size and density of the item, how could it not be a supercap? Can an alkaline-like or Li batt be made to that size & density?

May I ask what you mean by "density"? Do you mean the electrical capacity per kilogram (or possibly per unit volume)?

If so, I thought supercaps were nowhere close to the energy density of a lithium battery. Is that wrong?

Another thing: if the performance is as good as claimed, does it matter whether it is a supercap, or a solid state battery, or a normal lithium battery?

Sor for the basic questions - I have zero expertise in this area.

Energy per kg. Wh/kg.
I think supercaps now leapfrog Li batts.



Lithium-ion battery energy density typically ranges from 150 to 250 Wh/kg for commercial applications, with advanced chemistries pushing higher.

Current commercial batteries: ~350 Wh/kg (e.g., NMC, NCA, and nickel-rich cathodes).
Theoretical limit: 400–500 Wh/kg, challenging to achieve due to safety and cycle life trade-offs.

- 400Wh/kg was claimed, not 500.
- 150-244Wh/kg is seen for hybrid supercaps in the lab: https://pubs.acs.org/doi/10.1021/acs.energyfuels.4c02984

My bad, Dunkin has the 400 item.
Chery has 600Wh/kg.

I state again, to-market and %market makes things happen. If Donut gets their 400 out into everything and Chery 600 only gets into a few items.... etc etc.

[Randy222]

Maybe I am missing something so may I ask the audience what is the capacitance of existing supercapacitors and what is their voltage rating.

A little mind exercise: what would be the capacitance of a supercapacitor to match the energy storage of a 22.5Ah mystery cell ?
The cell energy capacity would be: 4.2V (nominal) * 22.5Ah * 3600 = 340.2 KJ.
A supercap charged at nominal voltage would have to be: 2 * 340.2 KJ / (4.2 V^2) = 38.571 kF (kilo Farad)!
Charged at 100V ---> 68.04 F.
Charged at 1kV ---> 0.6804 F.

Do such supercapacitors in the range of hundreds of thousands of Farad even exist rated at 4V ? And if they do, what is their physical size and weight ?
In the much spoken video we are shown a 4V cell. Any comment ?
---
Later edit: redo the numbers with a rough estimate of the cell shown in the video: 270A * 5 minutes / 3600 = 22.5Ah.

400Wh = 1440kJ

14000C 100v = 1440kj = 140F cap @ 100v

How physically dense that is...... I don't know, but they normalize the energy density to 1kg.

Using the Tesla model3 60kWh Li batt as base. Roughly 260Wh density.

400Wh/kg = (6.53mF @ 350v)/kg (260kg worth = ~1.7F)
260Wh/kg = (4.24mF @ 350v)/kg (~260kg is in a model3 60kWh batt) = ~1.1F

3x as far using (3x60kWh=180kWh) Chery
Chery @600Wh/kg, 180kWh = 300kg = 136,500cm^3 = 0.1365m^3 = ~5cu.ft.

This works out to be 1.15x less weight, 3x the range..... vs Tesla model3 60kWh batt.
https://interestingengineering.com/innovation/china-solid-battery-promises-800-mile-range

Li-ion batt material is about the same g/cm^3 density as graphene supercap.

Material   Density (g/cm³)   Volume for 1 kg (cm³)   Approximate Size (cm)
Activated Carbon   0.5 - 0.6   1667 - 2000   12.0 x 12.0 x 12.0
Graphene   2.2   455   7.6 x 7.6 x 7.6
Carbon Nanotubes   1.3   769   9.2 x 9.2 x 9.2
Carbon Aerogel   0.1 - 0.3   3333 - 10000   14.3 x 14.3 x 14.3

The math seems right.

With that small size Chery batt, being that energy dense, my guess is they are using lower voltage than the Li batts do.

[Electrodynamic]

The thing to remember about graphene is just because it left the news cycle doesn't mean countless people are not working on it. It's the perfect material for super capacitors, batteries and reinforcement fibers.

If they can ramp up production to commercial levels it's game over for batteries imo.

[Randy222]

Does anyone have the efficiency numbers for the tech, say Li-ion batt vs graphene supercap?

As example, fill the thing with 1kJ, and then I empty the thing.

To put in 1kJ I must use more than 1kJ to place 1kJ.
To empty it I need to take out 1kJ, but some of that is wasted.

Assume the measurement is taken right at the item in/out connector, and not 1m down a cable, etc.

Funny story. Tesla charge wall thingy, if you place a kW-meter on mains, it will show you used almost 2x the energy given to battery. Talk about crippling the power grid.

[thm_w]

Does anyone have the efficiency numbers for the tech, say Li-ion batt vs graphene supercap?

You can google "coulombic efficiency lithium ion battery":
- Lead acid ~80%
- LFP 90-95%
- NMC 85-95%
- graphene supercap 90-99%

Funny story. Tesla charge wall thingy, if you place a kW-meter on mains, it will show you used almost 2x the energy given to battery. Talk about crippling the power grid.

tesla powerwall round trip efficiency is 80-90% not 50%. If you are measuring 50% something is wrong, maybe bad cells or leakage, or a bad clamp meter. Generally they would be charged during off-peak so its not "crippling the power grid" but doing the opposite.

[EEVblog]

Funny story. Tesla charge wall thingy, if you place a kW-meter on mains, it will show you used almost 2x the energy given to battery. Talk about crippling the power grid.

tesla powerwall round trip efficiency is 80-90% not 50%. If you are measuring 50% something is wrong, maybe bad cells or leakage, or a bad clamp meter. Generally they would be charged during off-peak so its not "crippling the power grid" but doing the opposite.

Yeah, 50% is way off, this is fairly well characterised.

[Randy222]

Funny story. Tesla charge wall thingy, if you place a kW-meter on mains, it will show you used almost 2x the energy given to battery. Talk about crippling the power grid.

tesla powerwall round trip efficiency is 80-90% not 50%. If you are measuring 50% something is wrong, maybe bad cells or leakage, or a bad clamp meter. Generally they would be charged during off-peak so its not "crippling the power grid" but doing the opposite.

Yeah, 50% is way off, this is fairly well characterised.

I will dig up the video that showed near 50%.
But even 80% seems dismal. Use and pay for 1kJ from util, and only put into the bat 0.8kJ ?
https://teslamotorsclub.com/tmc/threads/home-charging-efficiency.73181/

An electric stove is something like 240v 30A on a 50A ckt. 7.2kW. Would need to run the stove for 8.3hr to match the energy needed to fill a small 60kWh batt from zero to full. Sure, the norm is not 0 to full, maybe its 50% to full, so 4.15 hr on that stove. In real world nobody is running their stove 4.15hrs everyday, but we would expect all the EVs to start doing that, plus an extra 20% of waste. How does any grid handle that? My bet is no grid today or in next 10yrs can handle that load. At least with stove power there's not 20% being wasted. 7.2kw into a stove is 7.1999kw of heat for cooking.

Supercaps (and anything that uses electrical power) does not escape this issue either. The rate of power hungry devices being deployed (EVs, forklifts, lawn equip, farm equip, hospital equip, industrial manufacturing, etc and the like), is out-pacing advancement and upgrades to electrical transmission, aka "grid".

Power outages happen around the world all the time from down wires, generator failure, controls malfunction. How does stuff get charged when the grid is down for 1/3/15 days?

As for Donut new 400Wh/kg item, it does not appear to be dodgy at all, at least not in terms of feasible tech.

[Marco]

Round trip through an extra battery would be either for self consumption of PV, or for grid directed consumption balancing. EVs don't charge from empty to full every day. The thread topic is silly enough without this extra idiocy.

[Randy222]

Round trip through an extra battery would be either for self consumption of PV, or for grid directed consumption balancing. EVs don't charge from empty to full every day. The thread topic is silly enough without this extra idiocy.

50-100 everyday perhaps?
HPEVs can often take their smaller battery to near zero.

There's major hurdles to overcome when trying to move all the gasoline/diesel vehicles to rechargeable power source. The 1st being power transmission, and the 2nd being actual delivery. Around the world there are countless apartment complexes that may have avg density of 1.2 vehicles per apartment, and everyone just jockeys for a parking spot on some blacktop covered earth. How do they all plug in, and will every spot have available the numerous different types of plug-in connectors?

Anything just battery alone, cannot scale, not now and will be difficult and very costly in the future.

[Electrodynamic]

Round trip through an extra battery would be either for self consumption of PV, or for grid directed consumption balancing. EVs don't charge from empty to full every day. The thread topic is silly enough without this extra idiocy.

50-100 everyday perhaps?
HPEVs can often take their smaller battery to near zero.

There's major hurdles to overcome when trying to move all the gasoline/diesel vehicles to rechargeable power source. The 1st being power transmission, and the 2nd being actual delivery. Around the world there are countless apartment complexes that may have avg density of 1.2 vehicles per apartment, and everyone just jockeys for a parking spot on some blacktop covered earth. How do they all plug in, and will every spot have available the numerous different types of plug-in connectors?

Anything just battery alone, cannot scale, not now and will be difficult and very costly in the future.

It reminds me of the crypto-miner and data centers popping up everywhere. It's quite the scam. These operations get subsidies and pay a lower bulk rate while the taxpayers are on the hook for higher domestic rates (supply and demand) as well as the grid upgrade fees. Here in Alberta they brag about how low the power rates are while the service/transmission fees tripled. It's a joke.

On the upside most of my very Conservative oilfield friends in Alberta are all in on solar and wind. I pitched the engineering for solar farms to one oilfield guy who then built a 10MW solar farm. Another oilfield friend who hated renewables got 30 wind turbines on his farm and used the first payment to buy 1MW worth of solar. Weird how they all changed their mind so quickly and now they can't stop talking about how great renewables are.

AI claims if we banned all the crypto miners/data centers and power exports to the U.S. we could charge over 10 million EV's daily. Which accounts for about half of all personal vehicles. Since the U.S. claimed they "don't need Canada" it's an option. It's only 35 terawatt-hours (TWh) of electricity or 2% of the market, they won't miss it. We could make Canada even greater.

[thm_w]

I will dig up the video that showed near 50%.
But even 80% seems dismal. Use and pay for 1kJ from util, and only put into the bat 0.8kJ ?

80% was the worst case, many battery backups are 85-95% which is completely fine, because again, they can be set to charge off-peak. Some power companies will even pay you to take off-peak power, or give it away for free (Dave has ~1h free of power).

An electric stove is something like 240v 30A on a 50A ckt. 7.2kW. Would need to run the stove for 8.3hr to match the energy needed to fill a small 60kWh batt from zero to full. Sure, the norm is not 0 to full, maybe its 50% to full, so 4.15 hr on that stove. In real world nobody is running their stove 4.15hrs everyday, but we would expect all the EVs to start doing that, plus an extra 20% of waste. How does any grid handle that? My bet is no grid today or in next 10yrs can handle that load. At least with stove power there's not 20% being wasted. 7.2kw into a stove is 7.1999kw of heat for cooking.

Not sure what you are ranting on about but the average electric cooktop is not 100% efficient it is 75%. If you go with induction it jumps to 85%+.

[Analog Kid]

I will dig up the video that showed near 50%.
But even 80% seems dismal. Use and pay for 1kJ from util, and only put into the bat 0.8kJ ?
https://teslamotorsclub.com/tmc/threads/home-charging-efficiency.73181/

An electric stove is something like 240v 30A on a 50A ckt. 7.2kW. Would need to run the stove for 8.3hr to match the energy needed to fill a small 60kWh batt from zero to full. Sure, the norm is not 0 to full, maybe its 50% to full, so 4.15 hr on that stove. In real world nobody is running their stove 4.15hrs everyday, but we would expect all the EVs to start doing that, plus an extra 20% of waste. How does any grid handle that? My bet is no grid today or in next 10yrs can handle that load. At least with stove power there's not 20% being wasted. 7.2kw into a stove is 7.1999kw of heat for cooking.

Supercaps (and anything that uses electrical power) does not escape this issue either. The rate of power hungry devices being deployed (EVs, forklifts, lawn equip, farm equip, hospital equip, industrial manufacturing, etc and the like), is out-pacing advancement and upgrades to electrical transmission, aka "grid".

Power outages happen around the world all the time from down wires, generator failure, controls malfunction. How does stuff get charged when the grid is down for 1/3/15 days?

This line of inquiry is worth pursuing.

I don't have any hard data to share here, but let me tell you about an epiphany I had several years ago:

I was flying into Minneapolis, Minnesota in the dead of winter.
As we descended toward Lindbergh Field over the vast urban area, I could see hundreds of houses stretching away into the distance, all covered by snow on the ground.

It was goddamn cold. Some days during my stay got up to the single digits (Fahrenheit).

I knew that most of those houses were heated by fossil fuels, mainly natural gas. Sure, some of them, especially newer ones, had electric heat (and air conditioning), but those were in the minority.

It then struck me what an enormous task it would be to suddenly convert all of those dwellings to "sustainable", non-global-warming-causing (supposedly) energy sources.

Meaning electricity.

I leave it to you to connect the dots here.

Seems to me that the supposedly smart people who are pushing us towards this "sustainable" future, including supposedly trained engineers and pointy-headed scientists, are actually fucking idiots. Because apparently they have not thought this scenario through: all the new generation sources that will be required, not to mention the distribution infrastructure, the on-line storage, all of that.

I have to question whether this wholesale transition to an electric-only future is even possible, given all the restraints here.

Plus an increasing world population. And a population that, thanks to rising social equity movements, is demanding an increased standard of living. All of which requires energy.

We need someone to look at the totality here and come up with a "theory-of-everything" analysis to see if this is even remotely within the realm of possibility.

[TimFox]

Many people on this site are paranoid about gaseous hydrogen in pipelines (fear of hydrogen embrittlement, even at normal temperatures), but distribution of hydrogen can use the existing natural gas pipelines with minor modifications.
I remember (ca. 1960) when the local gas company exchanged the orifices on our gas stove when Duluth (Minn.) changed from “town gas” (coal gas) to natural gas (when the pipeline reached us).  Town gas was too expensive for home heating, but much of the city switched from coal to natural gas thereafter.

[thm_w]

Seems to me that the supposedly smart people who are pushing us towards this "sustainable" future, including supposedly trained engineers and pointy-headed scientists, are actually fucking idiots. Because apparently they have not thought this scenario through: all the new generation sources that will be required, not to mention the distribution infrastructure, the on-line storage, all of that.

Norway is already at 99% renewable energy, Iceland 100%, Denmark 88%, and those are cold climates. But they aren't filled with brilliant skeptics like yourself, clearly you know best. Even though you can't be bothered to do any research or calculate any numbers.

https://en.wikipedia.org/wiki/List_of_countries_by_renewable_electricity_production

[ejeffrey]

It then struck me what an enormous task it would be to suddenly convert all of those dwellings to "sustainable", non-global-warming-causing (supposedly) energy sources.

Meaning electricity.

I leave it to you to connect the dots here.

Seems to me that the supposedly smart people who are pushing us towards this "sustainable" future, including supposedly trained engineers and pointy-headed scientists, are actually fucking idiots. Because apparently they have not thought this scenario through: all the new generation sources that will be required, not to mention the distribution infrastructure, the on-line storage, all of that.

Oh my god you are GENIUS!  You figured out that gas heat is common in the midwestern US!  You must be the first person to think of this!  What a bunch of fucking idiots all those people who do this for a living are!  Did you just figure this out this year, or have you been sitting on this golden knowledge for years without telling all those "supposedly trained engineers" how stupid they are? 

We need someone to look at the totality here and come up with a "theory-of-everything" analysis to see if this is even remotely within the realm of possibility.

That has happened and is happening, you just don't read it, and instead invent nonsense on the internet and pretend that you know what you are talking about.  The reality is that doing careful analysis of things like this is super boring, and basically nobody except the people who need to know read those reports.

tl;dr: it can be done.  It can be done with the techonology we have now.  It will take decades.  The best time to start was 20 years ago, the second best time is today.  Infrastructure like that lasts typically 50 years, and it's rarely worth ripping out working infrastructure.  So the best bang-for-buck is changing how we build new things, and also upgrading when things naturally need replacement or upgrading.  That causes natural turnover in a few decades, and avoids sudden demand spikes without the required distribution and generation infrastructure.

[mikeselectricstuff]

It then struck me what an enormous task it would be to suddenly convert all of those dwellings to "sustainable", non-global-warming-causing (supposedly) energy sources.

Except that these things never happen "suddenly". Just like a whole street doesn't suddenly all buy EVs and plug them in at the same time.
Infrastructure evolves gradually.

[Electrodynamic]

Seems to me that the supposedly smart people who are pushing us towards this "sustainable" future, including supposedly trained engineers and pointy-headed scientists, are actually fucking idiots. Because apparently they have not thought this scenario through: all the new generation sources that will be required, not to mention the distribution infrastructure, the on-line storage, all of that.

Norway is already at 99% renewable energy, Iceland 100%, Denmark 88%, and those are cold climates. But they aren't filled with brilliant skeptics like yourself, clearly you know best. Even though you can't be bothered to do any research or calculate any numbers.

https://en.wikipedia.org/wiki/List_of_countries_by_renewable_electricity_production

I agree many countries are getting close to 100% renewables for power generation. Every country could do the same using known technology but there's a catch. Most of this doesn't include heating or heavy transport.

Here in Alberta it hit -30C a few days ago and my 100,000 btu/hr high efficiency natural gas furnace was running 50% of the time. Below is a graph of my furnace supply temperature from my home automation. 100,000 btu/hr works out to about 30kW or 136A @ 220v electrical. Even if we averaged the demand out it's still 68A which is close to 70% of my 100A service and electrical panel capacity just for electric heating. It gets worse and last year we saw a couple weeks of -35C to -40C with 80 kph winds.

Power generation technology is definitely getting better and the future is electric but were not quite there yet imo.

[Marco]

Did someone set a bunch of bots on this thread for some reason? In that climate you use GSHP, you don't heat at COP 1 electrically.