Are solid-state batteries the future, or just a promise?
Companies have promised the battery that swaps the liquid for a solid for years. Some work today in pacemakers; the car version keeps slipping.
โถ Start the storySolid-state batteries are both: a real technology already at work in small devices, and a promise for cars that has not yet been delivered. A solid-state battery uses a solid electrolyte to carry ions between the electrodes, instead of the liquid or gel in conventional batteries. In theory it offers much higher than typical lithium-ion batteries. Yet while many companies have promised at the gigawatt-hour scale in the 2020s, whether their batteries are ready is unknown.
Why the excitement? The solid electrolyte could act as an ideal separator that lets only lithium ions through, which might solve several problems of liquid-electrolyte lithium-ion batteries, including flammability, voltage range and mechanical strength. In theory, it would also mean more energy for the same weight.
Conventional lithium-ion
- Liquid or gel carries the ions
- Flammable electrolyte
- Proven, widely made
- Lower in theory
Solid-state (promise)
- Solid carries the ions
- Potentially safer, denser
- Cost and scale unsolved
- and contact problems remain
The idea is old. Michael Faraday discovered solid electrolytes between 1831 and 1834. And such batteries are found today in and in RFID and wearable devices. The part not yet solved is the big one: making them cheap, durable and scalable enough for cars. To displace lithium-ion, they must overcome challenges in energy and power density, durability, material costs and chemical stability. One 2012 estimate put a single 20 amp-hour thin-film cell at US$100,000, and a high-range car would need 800 to 1,000 of them.
1831โ34
Faraday discovers solid electrolytes
2017
Goodenough unveils a solid-state glass battery
2022
JAXA reports solid-state batteries working on the ISS
2023
Toyota says no commercial solid-state use before 2027
2023
Panasonic announces a prototype it says charges 10โ80% in 3 minutes
Companies keep announcing dates, and the dates move. In June 2023 Toyota said it would not use commercial solid-state batteries until at least 2027. Each announcement is a promise to check, not a fact.
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Recap
Solid-state batteries are real but unfinished: cost, pressure, interface resistance and dendrites still stand between the lab and the car.
๐ก A trick to remember it ยท Swapping the liquid for a solid is like swapping soup for a brick: the brick cannot spill, but now you have to make sure it touches everything.
Surprising fact ยท Faraday discovered solid electrolytes in the 1830s, and such batteries already power pacemakers.
Sources (1)
No source, no claim. Every fact in this lesson (14 claims) cites at least one of these.