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Sodium batteries hit 458 Wh/kg: New material closes gap with lithium
(interestingengineering.com)
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this post was submitted on 23 Dec 2024
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Wish they gave the current energy density of lithium batteries for comparison.
Here's a neat comparison of how different chemistries preform. Higher up is higher energy per weight.
Looks like this is pretty old though
It’s a range, but LFP is generally in the 90-160wh/kg and NMC (lithium manganese cobalt oxide) tops out around 275 wh/kg.
It’s not quite double, but doubles the density of most mass manufactured cells. Time will tell if it gets to scale, but it’s a step in the right direction.
Feeling stupid: doesn’t this mean more energy per kilogram is possible with Na cells?
Lithium ion is around 265-280wh/kg but hydrogen is already in the kWh
Isn’t most of the weight with hydrogen coming from the high pressure tank and gas regulator?
My impression is that the gas is light but whole system hydrogen is pretty heavy.
edit: Did some more reading. Hydrogen is still competitive on a Wh/kg basis, but worse on a Wh/L basis. Larger tanks are harder to fit in passenger cars than batteries and hydrogen’s poor whole system efficiency has kept fuel prices high while lithium batteries and solar power keep getting cheaper.
H2 to get weight of tank down and highest density can be liquified. This works best by far for aviation that refuels right before takeoff. Can work for commercial boats as well. Costs more energy to liquify than compress.
This makes hydrogen even more expensive and pushes it further into niches which need maximum range at any cost.
Renewable h2 can be cheaper than gasoline or kerosene. Even with liquifaction. Has to use behind the meter or wholesale renewables instead of fixed utility pricing with transmission costs.
Planes typically spend 100x in fuel over lifetime compared to price of plane
Where are you finding this cheap renewable H2?
Or is this a theoretical future development?
I'm assuming the concept they're thinking of goes something like: Using renewable energy like solar and wind to convert water (or some other source of H2) into liquid H2 for the increased energy density compared to charging lithium batteries or equivalent with those same renewables.
There'd be tons of energy loss along the way, but since renewables are effectively "free energy," I can see that it would work in theory.
Right, hydrogen only makes economic sense if the fuel is free because the whole system efficiency stinks compared to BEVs.
Making h2 at less than $2/kg from renewables is achievable today. 300 bar at $2. Lh2 at $2.50.
Sales prices are much higher because capacity is still low, and toyota bundles some free to its fcev customers, and sales volumes are low such that a high profit margin is required to pay for filling infrastructure.
$2/kg is equivalent range in a fuel cell compared to 1$/gallon gasoline. That is much less than refinery sales prices of gasoline or diesel.
Consumer prices have chicken vs egg problem.