That's still a 22% drop in capacity after only 30 charge cycles; this system has a long way to go before becoming a practical battery.

Lithium batteries are over 95% efficient, so a long way indeed. Since the battery contains water, I assume it doesn't work below 0 C.

If the h2o ices up on that side, what happens to the battery? or is it not possible?

If a battery's stated capacity is say 2000 mAh then 1 C for that battery is 2000 mA.

Recommended discharge and charge (if applicable) rates are usually specified in terms of C. For example the usual recommendations for charging Panasonic Eneloop batteries is 0.5 - 1 C. So if you are charging an AA which has about 2000 mAh capacity that would be 1000 - 2000 mA, but if you were charging an AAA which has something like 900 mAh capacity that would be 450 - 900 mA.

E.g.—

• How much capacity per dollar?

• How much capacity per kilogram?

• How much capacity per litre?

• How quickly can it be charged?

• How quickly can it be discharged?

• How much energy is lost between charging and discharging?

• How predisposed is it to catching fire?

• How available are the materials needed to manufacture it?

• How available are the tools/skills required to manufacture it?

• How resilient is it to mechanical stress, e.g. vibration?

• How much does performance degrade per cycle?

• How much does performance degrade when stored at a high state of charge?

• How much does performance degrade when stored at a low state of charge?

• How much does performance drop at high temperatures?

• How much does performance drop at low temperatures?

• How well can it be recycled at end-of-life?

A sufficiently bad answer for any one of these could utterly exclude it from contention in many usages. A battery which scores well on everything except mechanical resilience is a non-starter for EVs, for example. On the other hand, a battery that's no good for EVs might be great for stationary storage.

I'm only a layperson and this list is the result of just a few minutes thought. I'm sure someone with more familiarity with the subject could double this list. But the point is, when you daydream about some hypothetical future battery tech, you need to appreciate just how well today's lithium chemistries score in so many areas.

The thing is though that you don't have to beat it on every metric to be useful, you have to be _good enough_ on every metric and then really good on one or two.

For example, it's absolutely fine for a battery to weight five times as much if it doesn't need to be portable. Five times as heavy but half the cost per MWh? That's great for grid storage!

Twice as expensive and non rechargeable but 4 times the capacity (per unit volume)? Great for pacemakers!

It's all about finding the right niche.

On the other hand an electric aircraft battery needs 10/10 on pretty much all of them (except perhaps cost - up to a point).

And bombs. When it comes to energy density, be careful what you wish for.

A more powerful battery isn't going to enable something like this, it can already be done.

Your point stands in general, but this is possibly worst example of winning in a single metric. New technologies are almost always more expensive than old technologies to begin with, so they need to provide some non-cost advantage at the outset.

At least for chemical batteriers, cost and weight are going to be correlated once the technology is mature. At sufficient scale and maturity of process, the material inputs become a significant fraction of the cost.

Note also that less mature processes are likely to be much more expensive than their inputs.

This means that for such a theoretical battery to exist, the inputs would need to be 5x cheaper and it would need to rely on an a pre-existing manufacturing process.

Lithium-Ion became dominant not by being the cheapest, but by having an incredible energy density. Since there was built-in demand, there was a lot of interest in making them cheaper.

The examples I was thinking of with this particular metric were Ambris liquid metal cells: https://ambri.com/solution/ and iron-air batteries: https://formenergy.com/technology/battery-technology/

Both of these technologies have additional advantages on top of cost that I didn't bother going into: namely they degrade less with use and both have no risk of thermal runaway.

Because that sure how that reads....

Although it's tricky - I'd never have thought someone called "Goodenough" would invent something so revolutionary.

That's like saying that horror scopes and phrenology have good track records.

Then why are you trying to rationalize it as being true?

Month of birth does have a little bit of predictive power

Not for what horror scopes are

During the first 5 seconds of reading a publication on batteries I should be able to answer at least 1 or 2 of those questions.

Note the article is a summary of the research, not the research itself.

https://insideevs.com/news/581729/volumetric-energy-density-...

The graph is taken straight from the DOE website, here:

https://www.energy.gov/eere/vehicles/articles/fotw-1234-apri....

Without attribution of course. They just re cited the paper the DOE cites.

The paper has no such graph:

https://www.osti.gov/pages/servlets/purl/1842609

The graph is clearly wrong.

(The cited paper does not contain this graph, see https://www.osti.gov/pages/servlets/purl/1842609)

I'd file this under gimmick rather than novel tech.