Jun 01 2021

Graphene aluminum ion batteries

Damn, I hope this one is true. Battery technology is absolutely key to our energy strategy going forward. Right now the cutting edge is lithium ion batteries, which are great, and good enough for our current purposes. They allow for cars with a range of about 350 miles, which is more than enough for most purposes. They are barely, however, energy dense and cost-effective enough to use for home backup power. This is still an expensive option, out of reach for most people. They are fine for small technology, like laptops and cellphones.

I have been following battery technology news for years. At first it seems like we are always on the cusp of a major breakthrough. Then you realize that none of these advances are breakthroughs, and the media hype always glosses over or even ignores major limitations. For a useful commercial battery you need to have several features simultaneously, and any one can be a deal-breaker. We need high energy density (energy per volume) and specific energy (energy per mass). It also needs high power density – the ability to absorb and produce energy quickly, enough to run a car. It further needs many charge-discharge cycles, enough for daily charging for years if not decades. It further needs to be stable so that it does not spontaneously catch fire. And finally it needs to be made of reasonably common materials. Not being toxic is a bonus, as is being recyclable.

Lithium-ion batteries fit this fairly well. They do have a tendency to burst into flames if they overheat, but that is improving. They do require some rare-earths and also cobalt in their construction, which will ultimately be limiting.

So far, whenever I read about a leap in battery technology, it turns out that the leap is in only one or a few features, but other features are below the water line. The media report then always says something like – all we have to do is scale up, or figure out this one little problem, and we’re good. But the one little problem is the rub, and most of the time it keeps the breakthrough from being a breakthrough.

But I also learned from following this news over many years that, while the breakthroughs rarely come (arguably the last one was the shift to lithium-ion), the net result of all the discovery is a steady incremental advance in battery technology. This adds up over the years, so if you are patient you do get the breakthrough, just in slow motion over years. I have resigned myself to this slow but steady incremental progress. It does add up, and if it keeps going for the next few decades (a big if, but not unlikely) battery technology will have been transformed, and we will eventually have the batteries we want and need. Of course, by then uses will also evolve and we will want still better batteries.

In any case, always in the back of my mind is the thought that it would be really nice to have a genuine breakthrough, something to put us a decade or so ahead in one jump. This would likely come from shifting over to a new battery technology, replacing lithium ion with something else, making a jump and then continuing the incremental advances from there. So far I haven’t seen it. Everything presented as the next possible jump in battery technology still has one ore more significant impediments, and we don’t know how long it will take, or if, we can overcome them.

However, I recently came across a new battery technology that seems, as far as I can currently tell, to have all the necessary features – graphene aluminum ion batteries. I’m not there yet, I have been burned too many times before, but all I can say is that so far I don’t see the “gotcha” with this technology. It seems to have it all.

Aluminum ion batteries have been studied for a while, of course, no technology comes out of the blue. The advantage is that aluminum ions each carry three electrons, instead of one for lithium. The ions are of similar size, so this essentially triples the energy density of aluminum ion batteries compared to lithium ion. They use common materials (aluminum, you may have noticed, is dirt cheap. It literally comes from dirt, and is the third most abundant element in the crust, and the most abundant metal. These batteries are more stable, have greater lifespan (more charge-discharge cycles), and can be charged much faster. I have seen reports between 20-70 times as fast as lithium-ion.

The trick with aluminum ion has been control, since each ion carries a triple charge. That is where the graphene comes in. This makes the battery a double-bonus for me, because I have also been keeping an eye on the promise of graphene. This is a true advanced material, made entirely of carbon. It has great conductive properties and strength, and use in batteries has been one of the promising applications.

Again, being jaded by premature and false promises over decades, I know that having a battery in the lab is one thing, manufacturing it is another. For that reason, I have taken a, “I will believe it when I see it” approach. I am also wary of claims of “5-10” years, or, “all we need to do is figure out how to scale it up,” type claims. But this time there is an Australian company who claims they will have coin batteries in six months, laptop and cellphone batteries in 18 months, and car batteries by 2024 – ready for consumer testing, if not mass production. I am skeptical of corporate press-releases, but the short time-frame is encouraging. It is more on the “create buzz for the market” timescale, not “let’s lure in investors” timescale. But we’ll see.

If this all turns out to be accurate, what would this mean? Let’s just focus on the EV industry, and assume triple the energy density but at the same cost (they claim it will be lower), and 20 times recharge speed (the very low end of estimates). This would be a game-changer. Right now you can get a 300 mile range for a $20,000 battery (about). We could therefore triple the range at the same price, but I don’t think that is what would happen. The question is – where is the sweet-spot of range, cost, and battery size and weight? I think something like 600 miles is close to the sweet-spot. That should be enough to erase range-anxiety, because you can basically drive all day then recharge overnight. That battery would cost about $14,000.

But also, with a recharge rate 20 times faster, you could recharge to full in about an hour. The limiting factor, in fact, would not be the battery but the electricity source. A fast-charging station could add miles to your range in the time it would take for a bathroom break, and fully recharge over lunch. This would not eke over the tipping point but leap over it, essentially removing any reason not to go EV.

There are other companies working on this technology also, but none have announced being closer to market than the Australian company. They are a graphene production company, and they make graphene from methane (which is better than burning it).

I think I have been clear that I remain skeptical of all of this, just based on history if nothing else. But there is nothing implausible in the claims, and this technology has been brewing for a while. I really hope this all works out as advertised, in fact they should do everything they can to accelerate the timeline. This is the breakthrough we need right now.

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