this post was submitted on 03 Jul 2023
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If we're talking approaching fundamental limits, Hydrogen fuel cell is not a great comparison. A high pressure tank can only get so light, even with linerless ultra high strength carbon fiber pressure vessels, the mass of the vessel is maybe 6-10x the mass of the hydrogen it carries. To increase specific energy there you need to go to cryogenics which is a whole technology leap and has its own set of challenges.
Battery tech has been improving more than you have seen, clearly. Since '08, lithium batteries have increased energy density by 8x (https://www.energy.gov/eere/vehicles/articles/fotw-1234-april-18-2022-volumetric-energy-density-lithium-ion-batteries). The best LiPo batteries are around 0.9MJ/kg right now, but there's no fundamental reason a battery couldn't achieve 9MJ/kg. Lithium-air batteries could theoretically achieve way higher energy density than that even (https://en.m.wikipedia.org/wiki/Lithium%E2%80%93air_battery), and have already been demonstrated in a lab to achieve more than 5x what current commercial automotive batteries are doing.
Except those fundamental limits are far higher. The fact is that hydrogen stores energy at 120 MJ/kg. Even at 5% weight efficiency, that's 6 MJ/kg. Or 1,666 Wh/kg. At 10%, it is 3,333 Wh/kg. Far beyond any battery.
Your link is seriously lying. 8x is the gap between lead-acid and li-ion batteries. The claims are simply impossible. The author must be unknowingly comparing lead-acid battery powered cars to li-ion battery powered cars. I cannot see any other way his claim is true.
A lithium-air battery is literally a fuel cell. In fact, what did you think hydrogen fuel cells were this entire time?
On one had we've got links to the department of energy and to Wikipedia. And just some hand waving on the other hand.
It's wrong because li-ion batteries at the time were way better than what it claims:
https://news.panasonic.com/global/press/en091218-2
This is from 2009, and already we reached 675 Wh/L. So there's no way the DoE link is true.