Aluminum batteries outlive lithium-ion with a pinch of salt

Assuming that's accurate, and batteries spend a majority of their usable lifetime around this capacity, perhaps battery estimates should be based off of the 80% capacity mark.

It depends on the use case. I believe LCO batteries are still more widely used since they are popular in small electronic devices rather than electric vehicles. These do not achieve the thousands of cycles you mention.

In general I don't like articles that simply talk about specs of Li-ion batteries as a whole without specifying the exact chemistry. Apple has different incentives when they choose a battery as compared to say Ford.

LFP is incredible, but LFP batteries are 5x larger than li-ion. The two aren't comparable. You won't find LFP batteries in cars nor smartphones.

NCA, a very common LiIon chemistry, is only 500 cycles as the article rightfully claims

The article is anywhere from 'correct' to off by 600% depending on which LiIon chemistry. But that's the nature of such a wide chemistry, there's so many LiIon out there it's hard to generalize.

NCA / NMC is common for phone and even EV applications though. So it's not necessarily wrong and both have similar endurance specs.

> Anyway, the article carefully avoids talking about energy density. Which is of course the key thing here.

No one cares about density in utility scale applications. It can be heavy as all heck but as long as it's cheap it will be an effective solar or wind battery.

If you "full de-charge" your car battery that battery is toast, so that's not a useful comparison.

And this is almost purely a function of the very first charge cycle the battery receives. If the initial charge cycle is fairly aggressive, you can actually pull something like 1500 cycles out of those older chemistries, at the cost of actual capacity. We're running tests on this right now in a lab in San Diego. Almost all non-solid-state Li chemistry batteries are similarly affected.

You'd lose 27% of capacity vs 8% capacity over a cycle test that lasted 2,5 years. https://youtu.be/i31x5JW361k?si=93KYNqKFVJRgSbKs&t=1216

"Anyway, the article carefully avoids talking about energy density. Which is of course the key thing here."

I agree. And as you say, there's a bit of inaccuracy in the article. In fact, it's more than just a little—not to mention the omissions.

What's so annoying about this article is that it's from the IEEE's magazine Spectrum where one expects the best—the most authorative, factual and most current—technical information available at publication time but it's often not the case.

Unfortunately, in recent years, the IEEE has been unduely influenced by commercial interests which has affected or slanted the accuracy of its reporting of science and engineering news. As Spectrum is the main face of the organization and its principal news outlet this is where the policy shift has been most obvious.

I could give other instances of bad or overly enthusiastic reporting of new tech where known downsides were either not reported and or downplayed but I'll refrain here as I don't have the issues of Spectrum immediately to hand to give specific references. Suffice to say, I became so disillusioned with stuff I was reading in Spectrum† that I terminated my 20-year-plus IEEE membership some while back.

My main criticism of this story is—as you correctly point out—carefully avoids talking about energy density, which has to be a crucial aspect of any story about new battery tech that's posited as a potential competitor and or replacement for Li-ion. That's damn obvious. If the researchers did not provide numerical comparisons (experimental and or theoretical) of the energy densities between their Al-ion prototypes and Li-ion in their paper/press release then Spectrum's editor should have provided a side/footnote on the matter.

Most of us already know that Li has a larger electrode potential‡ than Al, so Al is already coming from behind Li in this regard, but of course that's far from the end of the story as there are many other factors involved in addition to those benefits as promulgated by the researchers, namely recharge cycles, safety and cost. For example, how does Al stack up against Li as far as electrode surface area (spongy metal surfaces, etc.)? We know from long experience with electrolytic capacitors that Al can be treated to have very large effective surface areas, in fact they can be enormous. If Al has the potential to be much better than Li in this regard then this new tech could certainly be a winner. As this is an obvious factor, Spectrum's editor should have mentioned it amongst others even if not mentioned in the original paper (in fact, Spectrum should have criticized its omission if the case).

In summary, one would hope this research leads to much better and safer batteries but the IEEE—as the premier representative for electrical and electronic engineering/engineers—has done precious little in providing us with information that actually matters.

__

† Whilst I've strong criticisms of the IEEE not all are negative, many of its specialist publications are quite excellent including Proceedings of the IEEE.

‡ From Wiki: Standard electrode potentials:

Li: Li+ + e− ⇌ Li(s) -3.0401V

Al: Al3+ + 3e− ⇌ Al(s) -1.662V

Edit: It was only after I'd written this comment that I was able access the original ACS research paper (initially I'd difficulty downloading it). I've since skimmed it several times and I need to read it thoroughly to get a proper understanding but it's pretty short on the issues I've raised. Thus, my point that Spectrum should have mentioned these shortfalls still stands.

But it's right there in the article:

https://pubs.acs.org/doi/pdf/10.1021/acscentsci.4c01615?down...

> The cell with F-SSAF electrolyte and pyrolytic graphite (PG) cathode show reversible capacities of 83, 81, 79, 77, and 75 mA h g−1 at the current densities of 20, 40, 60, 80, and 100 mA g−1 (Figure 2a).

so 83 Ah/kg (at 20 A/kg), and at a cell voltage of ~ 2V thats ~166 Wh/kg.

Exactly the sort of thing the planned-obsolescence cartel doesn't want.

I'm guessing the weight (energy density) issue matters for overall costs because of shipping?

EVs in particular are entirely about batteries. The energy density of fossile fuels is the only thing going for combustion engines. Electric motors are simpler, cheaper, more efficient, more powerful, better for the environment, the only problem is storing the electricity needed to power them. Electric cars actually came before gas cars, that's 19th century tech! The only reason we are only starting to see them back on the roads is because until now, we didn't have good enough batteries.

I expect such research to pay off eventually in the same way. No big breakthrough, but maybe in the future, you will look into buying a new car and realize that that $10k electric car you thought would be useless actually has decent range, that the generator section in the hardware store has been mostly taken over by battery packs and that city buses do not sound the same as they did before.

On a boat, Aluminum "corrodes" and forms an oxide layer (also known as sapphire), which then protects it from further corrosion. But, said layer is not electrically conductive (or in this case does not allow Al ions to flow into the electrolyte), so you need something to prevent the protective layer from forming.

> In contrast, a typical Li-ion battery retains only 80 percent of its charge capacity after 300 to 500 cycles, depending on conditions.

LiFePO4 lasts for about 3000 cycles before 80% degradation, not 300-500.

> The batteries were also tested at temperatures as high as 200 degrees Celsius

Thermal runaway on LFP is 120C, not 200 but still not a temperature you will easily hit.

And finally (as always):

> before the Al-ion battery is ready for commercial applications, its energy density will need to be improved

Which means it's not commercially viable.

LiFePO4 is cheap to manufacture, uses lithium, iron, phosphate, all of which are fairly plentiful and lasts for over 3000 cycles (before reaching 80% capacity).

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Dear battery technology claimant,

Thank you for your submission of proposed new revolutionary battery technology. Your new technology claims to be superior to existing lithium-ion technology and is just around the corner from taking over the world. Unfortunately your technology will likely fail, because:

[ ] it is impractical to manufacture at scale.

[ ] it will be too expensive for users.

[ ] it suffers from too few recharge cycles.

[ ] it is incapable of delivering current at sufficient levels.

[ ] it lacks thermal stability at low or high temperatures.

[ ] it lacks the energy density to make it sufficiently portable.

[ ] it has too short of a lifetime.

[ ] its charge rate is too slow.

[ ] its materials are too toxic.

[ ] it is too likely to catch fire or explode.

[ ] it is too minimal of a step forward for anybody to care.

[ ] this was already done 20 years ago and didn't work then.

[ ] by this time it ships li-ion advances will match it.

[ ] your claims are lies.

----------------------------------------------------------------

Source: https://news.ycombinator.com/item?id=28025969

I can't tell if this is one of those. It does have many of the hallmarks.