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> The flavour you want is polymer, single ion conducting solid state with an ion transport activation energy below 10kJ/mol at room temperature and no phase transitions from -40C to 80C.

what makes it so? I don't know anything about this subject, I'm really curious now about what the perfect battery would be.

I’m still a novice on the material science behind it, but what is QuantumScape lacking here if anything, and why is it a dealbreaker?

Are anyone building the battery you described?

"no phase transitions from -40C to 80C."

Well that's fine for terrestrial use but aerospace needs that range to be expanded a little in both directions, otherwise it won't be much of a holy grail if it won't cover the needs of one of the largest growing industries.

For disposable applications like that, aren't there single-use chemistries that are better already? I'm thinking by analogy to things like:

- WW2 proximity fuzes that had batteries where the electrolyte was in a vial that got smashed by the G-forces of being shot out of a cannon providing power to the radio inside for the 10 seconds it needs to get to the incoming aircraft

- Hearing aid Zinc-Air batteries, that are extremely energy dense because you only have to actually manufacture the anode, the cathode is the entire atmosphere of the Earth

- Missile batteries, which are often Lithium-silicon/Iron Disulfide batteries that borrow some thermal energy from the rocket motor to get a molten salt electrolyte

If the thing is going to blow up anyway, does it need to be light? Wouldn't you rather have more cheaper drones?

I can - it’s called a bomb. Some of the problems with batteries are heat dissipation (one of those problems that superconductors would mostly solve), fire safety, and end of life disposal. Higher energy density makes it even worse.

A good place to start would be a BMS on individual cells that monitors them for general degradation, unexpected discharge, unexpected temperature changes, and can remove a failing cell from the array.

The past 20 years have made lithium ion 2-3x more dense, both because of some chemistry changes and because of better pack level design.

And it's still improving at about 5% per year.

I don't think 10x density is possible without getting into nuclear, at least not with the chemistries we know of today, everything at a certain point becomes an explosive.

Speaking of nuclear, getting tons of the material that powers mars rovers and putting them in every home would generate enough power for decades... At the cost of being able to build a nuclear bomb in a garage.

How is billions every year on R&D not enough, especially when you measure consistent improvement year over year in the technology?

10x energy dense does not mean 10x safer. Gasoline is still widely used because it is considered one of the safest options around!

The problem is more nuanced than just "let's do all the battery density"

Agreed, but I think people can imagine and companies are very motivated: powertools, phones, laptops, watches, backup UPS, cars, hospital equipment... there's high demand for durable, long-lasting batteries. I think the research is there, it's just complex chemistry. We'll get there. Impressive to see the progress in EV batteries and they've actually turned out to be more durable than first feared.

I think, apart from finding better Batteries altoghether, we should build multi-tier batteries inspired by biology. Humans have bloodsugar, sugar in the Liver and then fat. All of them have their respective properties with availability and amount. This way, engineering tradeoffs could be allocated much more fine grained. For example, a while ago I read about a startup building an energy storage where they heat up large amounts of sand to store the surplus of renewables. This could serve analogous to the fat in humans.

The article says $4B was put into solid state research/companies as of 2025 in the US alone. Seems like they are working on it

It should be relatively straightforward to imagine — we already have that in gasoline-powered internal combustion engines.

The Watt-hours per kilogram of good Lithium Ion batteries is around 250-280 Wh/Kg; for Lithium Iron Phosphate it's about 180 Wh/kg, and for Sodium-Ion about 170 Wh/Kg.

The raw energy in gasoline is about 12,300 Wh/Kg but automobile internal combustion engines get only about 20-30% efficiency yielding about 2500-3600 Wh/Kg. For aviation piston engines it is a bit better at 25-30$ so 3000-3600 Wh/kg.

So, the batteries, instead of being 10-12X the weight of the gasoline for the same net driving/flying range, could weigh about the same as the gasoline. So, a typical car with maybe a 16 gallon tank and 30 miles per gallon fills up with 128 pounds (58 kg) of gasoline to get 480 miles of range. The Li-Ion battery for that range would weigh something like 1300 Lbs (590 kg). That is a substantial additional weight for a car that could be 2800-3800 Lbs in ICE configuration, so 35-45% added weight (a bit less because of savings on the ICE engine, etc). This requires everything else to also be heavier, from the structural frame, the suspension system, and even the wheels and tires (which is also unsprung weight, further impairing performance).

With a 130Lb/60kg battery instead, and saving the weight of the ICE engine and fuel system, the overall car design could go much more lightweight, regaining a lot of performance and range, all while gaining the huge torque of electric motors.

In aviation, a battery systems of that weight would enable all-electric aviation to go from small performance niches to the default for general aviation.

So yes, it would be a HUGE benefit to achieve 10X energy density batteries, and we do have reference points for people to imagine it.

I think people can imagine lighter cars and laptops and things. Is there something bizarre that’s unlocked like battery powered space launches or something?

Not all batteries need to be mobile.

A 1 GWh grid scale battery takes up about 4 hectares at the moment. The UKs total energy use is about 2,000GWh a day.

It would need to use 240,000 hectares to store all energy requirements (eletric, transport, heating etc) for a whole month. Even in extreme cold conditions it would last a couple of weeks.

That would be about 1% of land use.

Depends on the application - each battery technology has a trade-off between energy density, cost, lifetime, safety, scalability, etc. Sodium may have a place in grid storage, although iron-air is being deployed today and is even cheaper and safer (but poor energy density, which doesn't matter much for grid storage - https://formenergy.com/technology/battery-technology/)

Cheaper yes. Non-aqueous sodium ion batteries (which are most of them) are more dangerous than LiFePO4 though.

BYDs battery stress testing: https://www.youtube.com/watch?v=WPTgg3joL5E

Yes, electricity should be the only abstraction layer to deliver energy to end user. We can extract a lot more energy from fossil fuels in large scale plants and also continuously switch out dirtier fuels with clean energy.

For example, no need to build natural gas infrastructure to every home. Use induction stoves (or electric coil -- already 67% of homes). Heat pump water heater instead of gas. And heat pump for HVAC.

If all energy bills are consolidated as electricity (instead of gas, natural gas and electricity), most people would install solar on their rooftops, buy EVs, and save ~$1000/month on energy bills.

This isn't true for most lithium ion chemistries.

The liquid electrolyte is the thing that releases most energy when the battery burns, more than the anode and cathode. Some also have a very low self ignition temperature.

IIUC, the main problem with the current Li batteries is that the two plates can over time grow material that will 1) degrade performance; and 2) make it more likely to short circuit and catch fire. Similarly with electric car batteries after accidents where the battery is damaged, short circuits, and then catches fire.

So the main risk here would be the likelyhood of short circuiting under different failure scenarios.

The energy "stored" in the light oil electrolyte of a battery is >10x more than the electrical energy or the energy released by reacting lithium alone.

An 18650 battery weighs ~50g and stores ~10 watt-hours. 10 watt-hours is 8,604 calories, enough to heat 50g of water by 172 C or 310 F. The battery would not even burn without a liquid electrolyte to ignite.

Isn't the key difference that flammable solids have a limited reaction surface when they burn, whereas flammable liquids can be wildly unpredictable?

I wonder about the youtube videos of someone driving a screwdriver through a battery pack.

Is that the electrical discharge, then the lithium going off, then the electrolytes?

There are a number of reasons why lithium batteries may catastrophically fail and catch fire. Dendrite shorts is one, another reason is poor alignment of the layers during assembly, allowing for eventual shifting of layers leading to internal shorting. Another is conductive or sharp debris getting into the battery during manufacturing, and after a while the anode/cathode separator getting pierced by the debris. Lots of reasons!

dendrites are not really a significant problem in popular batteries. It's associated with lithium metal, vs lithium in normal batteries is in the form of salts. Solid state lets you use metal, which is much more energy dense since you don't need the salts.

The most common lithium battery failure mode is that you have a hole in the plastic separator between the +/- sheets inside the battery, which shorts and causes a hotspot that eventually starts a fire. Dendrites cause the short by growing across the gap. In normal batteries it is caused by a manufacturing defect. The outcome is pretty similar.

dendrites are an inherent problem with liquid elctrolytes and I would have emphasized that as well