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Comment by mmazing | Hacker News Reader

I remember a few years ago reading an article about a breakthrough in Lithium Metal batteries, as opposed to Lithium Ion. Supposedly have 2x the power density at half the size, and don't burst into flames when punctured.

Anyone else remember that? I want those batteries.

Apparently the main issue is that they don't last as long as Li-Ion.

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The big competitors to lithium ion right now are LFP (lithium iron phosphate) and LTO (lithium titanate oxide). Neither have quite the power density of current lithium ion cells, but they're not that far off. LFP is quite popular right now for home storage and RVs. It is not nearly as prone to fire as lithium ion. LTO is even safer yet, it usually doesn't even pop the case if you abuse it to the point of destruction. LFP is improving density so it may be viable soon for EVs (in the US; in China they already use LFP), which manufacturers would love. Making the news for fires is really undesirable.

LFP have been popular as drop-in replacements for 12V batteries in motorcycles for years now, too, FWIW. Their cell voltage and resistance to charging damage make them excellent replacements. Their only real deficit is in the cold.

I might be wrong but it looks like neither of those are classified as a Lithium Metal Battery and are still a form of Lithium Ion.

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

https://en.wikipedia.org/wiki/Lithium-titanate_battery

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

and here's an article about using pure lithium metal as the anode

https://arstechnica.com/cars/2021/11/lithium-metal-hybrid-ba...

You seem to be well informed, is this just hype?

From what you know off the cuff, do LFP or LTO batteries have advantages in number of cycles or discharge depth? Both of those being even marginally higher would make them superior for home batteries, since the power density wouldn't matter nearly as much.

E: Wikipedia says low cost, less rare earth metals and longer lifetime. Sounds like a big technology.

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