Solid state batteries come in several flavours. Most of them don't stop dendrites.

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.

That is the holy grail of SS batteries.

If you know a bit about electronics, you might be a bit surprised by the term 'solid-state battery'. It's a poor analogue to the more common usage of solid-state with semiconductors, integrated circuits, etc. -- a "solid-state" cell is still a chemical cell. It's not a paradigm shift on the level of, say, replacing a relay with a MOSFET.

The article gives the technical reasons that answer the headline question (e.g. potential for better energy density)

I am surprised they didn't point out the literal "killer app" - military drones. Energy density is king for any airborne power source. And dendrite growth during charge/discharge cycling isn't as big a deal for that application (how many times would you need to charge a disposable weapon?)

We need way more research on batteries. People cant ingine what is possible if we make battery 10x energy dense.

fun fact: there is already a Sodium-battery with a solid electrolyte - but the operating temperature is above 300^C [0] [0] https://en.wikipedia.org/wiki/Sodium%E2%80%93sulfur_battery

When titles with rhetorical questions sound almost like dumb questions.

Aren't sodium batteries close to production and a lot cheaper and safer?

Ambri was working on large scale batteries which seemed like a pretty good idea (looks like they ran out of money): https://en.wikipedia.org/wiki/Ambri_Inc.

The Two Bit Da Vinci YouTube channel has a good video on solid state battery fundamentals and a deep dive into a battery company (ProLogium) that has demonstrated manufacturing at scale.

https://youtu.be/xQFVIs4leig?si=iOOt5gg_2MJAIoFR

Tangential to the main article point but…

The energy density scatter plot is physically correct but misleading and everyone makes this mistake.

From an engineering point of view you have to use work delivered at the end of the drive train not fuel raw energy content.

When you do that lithium ion batteries compare more favorably to liquid fuels. That’s because the conversion path is more than 90% efficient. For ICE engines you’re starting with only 20-40% Carnot efficiency (depending on how good and in good shape the engine is) and then losing in the transmission and then losing more because ICE cars have more other gears and moving parts. Power to wheel is pretty terrible. Most of the energy from gasoline heats the air around the car.

This is also why you get outrageous sounding but accurate things like: an EV charged on 100% coal fired electricity emits less carbon than a typical gasoline car. The fact that coal is literal pure carbon fuel is made up for by the high thermal efficiency of a giant supercritical steam turbine vs a small piston engine. Coal burns real hot too (steeper thermal gradient). So more of the energy from coal ends up doing actual work vs heating the air. (Well directly heating the air I mean.)

> because the liquid electrolyte currently used in batteries is flammable, replacing it with a solid could make batteries safer and less susceptible to fire.

The problem is primarily that batteries are storing a lot of energy, which can be released when things go wrong. The electrolytes (technically, the solvents) typically don't ignite under 750°F or so, which makes them less flammable than a lot of other common materials, and far less of a concern than, say, the lithium metal.

I'm not trying to build a solid-state battery...

Manufacturing the batteries would probably benefit from solid state. The Panasonic battery plant in the exurbs of Kansas City, MO has had two evacuations this year from thermal issues related to lithium-ion battery production, including one yesterday morning. [0] [1]

[0]https://www.kmbc.com/article/lithium-ion-batteries-catch-fir...

[1]https://www.kmbc.com/article/panasonic-plant-de-soto-evacuat...

Yeah I've made peace with this too

have I misread or 3/4 of the article explained what a battery is and only final tiny part got to "short-circuiting dendrites don't happen without electrolite"?

are dendrites why so many people are now burning down their apartment/complex charging their scooters

is LiFePo4 immune to dendrite shorts? Or do they happen just don't burn?