History, Politics And Current Affairs

Yesterday, I wrote a very brief LinkedIn post about solid state batteries (SSB). I expressed significant doubts that a small, unnamed Finnish startup could develop SSB with such parameters:
400 Wh/kg
Full charge in five minutes
Designed for 100,000 cycles
Lower cost than lithium-ion
etc.

I tried to find more information and discovered that it is probably not SSB, but an 'electrostatic bipolar capacitor', which I believe is "mistakenly" referred to as SSB.
Finnish Carbon Nano acts as a supplier of an "energy storage solution" (I can't put it any other way) for this unnamed Finnish startup. Their online presentation states parameters such as 50,000 cycles and 400 Wh/kg, which closely match the specifications of the so-called SSB from an unnamed company. However, this is not SSB; it is an "electrostatic bipolar capacitor".
This is likely a supercapacitor, which only achieves an energy density of 10-30 Wh/kg, so I am very curious (and many scientists who work on the development of supercaps), how is it possible to achieve the energy density of 400 Wh/kg.

I took a very close look at the profiles of the people behind Carbon Nano, and none of them has experience in SSB development. There is not a single peer-reviewed paper or even one relevant patent from these Finnish companies related to solid state batteries or even battery chemistry!

A statement from an unnamed small Finnish startup amazed the media by claiming they developed an SBB with a cycle life of 100,000 cycles, which damages the reputation of all companies and scientists working on real SSB development. I noticed that a lot of familiar faces, including bloggers, CEOs, and journalists, were led to believe this is about SSB; it is 99% not about SSB.

The main difference between SSB (rechargeable) and supercapacitors lies in their energy storage methods: Solid state batteries rely on reversible chemical reactions (redox) to achieve high energy density by storing energy in chemical bonds, whereas supercapacitors utilize an electrostatic mechanism (electric double layer) for quick charging and discharging, resulting in lower energy density and minimal chemical alteration.

This is the reason I placed a red flag on these Finish startups.

Craiglxviii wrote: ↑Fri Jan 09, 2026 8:26 pm

warshipadmin wrote: ↑Fri Jan 09, 2026 7:27 pm No I'm not talking about little planes, I mean 500km+ transport for 100s of PAX.

Yes, I mean ask him! That’s the end goal, he isn’t working on general aviation from what I recall.

Pdf27 wrote: ↑Wed Jan 14, 2026 8:55 am

Craiglxviii wrote: ↑Fri Jan 09, 2026 8:26 pm

warshipadmin wrote: ↑Fri Jan 09, 2026 7:27 pm No I'm not talking about little planes, I mean 500km+ transport for 100s of PAX.

Yes, I mean ask him! That’s the end goal, he isn’t working on general aviation from what I recall.

Sorry, missed this - haven't been on here much recently because the ICE debate is just getting too depressing.

At the moment state-of-the-art is ~100 miles or so on a certifiable aircraft, and the theoretical limit on Li-ion chemistry is about 2-4x this. It isn't hugely sensitive to aircraft size - if you double the weight of the aircraft you double the energy demand, so if you double the battery size the range stays pretty much the same. The problem is that short hops tend to have limited passenger demand, so justifying large aircraft is hard. That means battery powered aircraft are probably going to be under CS-23 (19 pax maximum) - there are projects to build much larger aircraft, but I haven't seen a credible one yet. This is simply because certifying a CS-25 aircraft is eye-wateringly expensive and can't be justified without a very large market.

If you want to use electricity to power a long-ranged aircraft, the current plan for the industry (out to 2050) is to carry some sort of fuel which reacts with atmospheric oxygen to provide energy. There is an ongoing debate as to what this will be - the US is leaning towards Sustainable Aviation Fuels (SAF), Europe had been leaning towards Hydrogen but has been hedging it's bets more recently. Both fuels can be manufactured from renewable electricity - SAF using green hydrogen to either hydrogenate agricultural waste or combine with direct air captured CO2 to form a liquid fuel.

What we are seeing - and is a large part of my day job - is hybridising thermal engines to reduce fuel burn by sharing power between fuel and battery. The level of hybridisation varies, mostly by aircraft range, and with smaller aircraft what we're seeing is the use of what are essentially giant APUs which act as range-extenders on a pure battery mission when you have to divert or to stretch battery life for longer flights, directly cutting fuel burn.

Here is everything we currently know about the Donut Lab solid state battery!

The claims for their cells include:

~100,000 charge cycles
Potentially ~50 million miles of use (!?!)
400 Wh/kg
5 minute charge time (~12C)

Here is what I saw at CES:

Displayed cells and modules were 3D-printed mockups, not live cells
The team would not discuss chemistry or manufacturing, increasing scepticism
Strong industry interest (~600 enquiries on day one)

Here are some key technical clues.

Battery:

Can be made in any shape (even structural components)
Claims no lithium (at all)
Voltage can be tuned to match existing systems
Supports very high current with constant current charging
Manufacturing appears to be stacked / pressed, not traditional jelly-roll cells.

Production claims:

1 GWh this year, 10 GWh next year
Comparable to a full EV gigafactory (bold claim!)
Available test data showed unusual charging voltage
Lifespan claims align more with capacitors than electrochemical cells.
Evidence points toward a capacitor-like system, not a conventional battery.

Finland connection:

Manufacturing planned in Finland.
Donut Labs has ties to Nordic Nano, a Finnish company working on printed, shape-agnostic solid-state energy storage.
Claimed 400 Wh/kg and 50,000+ cycles
Technology described as electrostatic bipolar capacitors

My current take:

This may not be a “battery”, but a super (ultra?) capacitor.
Some claims seem plausible, others feel extremely optimistic.
Extraordinary claims need extraordinary proof.

I hope it works out, but it needs some serious backing up with third party tests.

(Full youtube video available here: https://lnkd.in/eGjX3sMD)

Craiglxviii wrote: ↑Wed Jan 14, 2026 9:01 amThanks Paul. So we’re talking essentially REEV aircraft with IFEP architecture?

• Short hops - up to 1h / 100 miles - battery only (BEV).
• Longer hops - up to 3h/250 miles (diversion requirements are very restrictive hence the mismatch between endurance and range, and smaller aircraft don't want to sacrifice a seat to fit a toilet) - battery with range extender (REEV).
• Most applications - above 250 miles or so - thermal engine with battery boost (PHEV).

Pdf27 wrote: ↑Wed Jan 14, 2026 9:32 am More suggesting it's actually a supercapacitor:

Here is everything we currently know about the Donut Lab solid state battery!

The claims for their cells include:

~100,000 charge cycles
Potentially ~50 million miles of use (!?!)
400 Wh/kg
5 minute charge time (~12C)

Here is what I saw at CES:

Displayed cells and modules were 3D-printed mockups, not live cells
The team would not discuss chemistry or manufacturing, increasing scepticism
Strong industry interest (~600 enquiries on day one)

Here are some key technical clues.

Battery:

Can be made in any shape (even structural components)
Claims no lithium (at all)
Voltage can be tuned to match existing systems
Supports very high current with constant current charging
Manufacturing appears to be stacked / pressed, not traditional jelly-roll cells.

Production claims:

1 GWh this year, 10 GWh next year
Comparable to a full EV gigafactory (bold claim!)
Available test data showed unusual charging voltage
Lifespan claims align more with capacitors than electrochemical cells.
Evidence points toward a capacitor-like system, not a conventional battery.

Finland connection:

Manufacturing planned in Finland.
Donut Labs has ties to Nordic Nano, a Finnish company working on printed, shape-agnostic solid-state energy storage.
Claimed 400 Wh/kg and 50,000+ cycles
Technology described as electrostatic bipolar capacitors

My current take:

This may not be a “battery”, but a super (ultra?) capacitor.
Some claims seem plausible, others feel extremely optimistic.
Extraordinary claims need extraordinary proof.

I hope it works out, but it needs some serious backing up with third party tests.

(Full youtube video available here: https://lnkd.in/eGjX3sMD)

Craiglxviii wrote: ↑Wed Jan 14, 2026 1:59 pmBe interesting if so, my understanding is that weight doesn’t scale well at all for supercaps.

1. Everything is as reported and this small start-up get Nobel Prizes all around.
2. Values are not as reported / claimed and it's all vapourware.