Lower-cost sodium-ion batteries are finally having their moment

For a long time after reading "A Nation-Sized Battery"[1] I thought there was no way we could run a grid on wind/solar/battery without plenty of hydro/geothermal/nuclear for the windless nights, just due to the raw material requirement of that much battery.

Cheap batteries from earth-abundant materials change that completely. Iron-air is another possibility, though I think it's less efficient.

[1] https://dothemath.ucsd.edu/2011/08/nation-sized-battery/

They seem (both the article and the press release) to conspicuously avoid mentioning any details about important open problem with sodium-ion: Cycle life/longevity.

> On November 22, China’s Huawei announced a new patent for sodium-ion batteries named “Electrolyte Additives and Preparation Methods, Electrolytes and Sodium-ion Batteries.” The company’s latest work has focused on improving the shortcomings of sodium batteries – such as low coulombic efficiency and poor cycle life – by optimizing the electrolyte formula.

Yes, you've "improved the shortcoming." By how much? The lack of numbers is concerning.

Sodium ion has been in the labs for a while, but at least as of last I saw, they weren't managing more than a couple hundred cycles to 80% capacity. Lithium-ion is now typically thousands of cycles to 80% capacity (and associated higher internal resistance - 80% is just the standard benchmark for "lifespan" given the range of issues you see by that capacity loss). That they're "fluffy" batteries in terms of density isn't a huge problem for a lot of cases, but that their cycle life is "a few hundred cycles" has been a serious issue for any significant application of them.

That they don't mention this in the slightest implies, rather strongly, that they've not fixed that particular problem with it...

For a 70kWh battery pack, 300 cycles at 3 mi/kWh (a midrange average for year round driving) gets you 21MWh cycled through the pack, or 63k miles. Not exactly a stellar lifespan for a car battery pack.

That same pack at a lithium-ion standard 1500 cycles gets you about 315k miles.

Sodium has a gravimetric energy density of ~4 kWh/kg for complete oxidation (lithium has ~12 kWh/kg and gasoline has ~13 kWh/kg), so there's still plenty of room for improvement.

Dr. Shirley Meng has done some interesting work on anode-free solid state sodium ion batteries - current samples have 350 kWh/kg of gravimetric density, but only retain 70% capacity after 400 cycles.

Another Better Battery Bulletin. Nothing to see here, time to move on.

“We tend to be skeptical of news releases from companies,” he said. He specified that his comment applies to all battery companies." -Venkat Srinivasan

I'm glad sodium is having its day in this configuration of using them in batteries.

What I'm really trying to understand is how in the blazes we aren't using Sodium _directly_ as energy transport mechanism.

Using the Castner Process ( https://en.wikipedia.org/wiki/Castner_process ) you run the process of (caustic soda + energy) -> (water, oxygen, pure Sodium).

This process is 'perfect' in that you don't get contaminants; you lose nothing in this reaction. (It's decidedly imperfect in that the reverse reaction occurs during, so H2 wafts off, and it needs ~330ºC to run).

This process has been done to death in the early 1900s, but humanity hasn't done this stuff for a 100 years since the invention of a different process that turns NaCl into Sodium and Chlorine gas, because the latter is _also_ valuable, whereas water aint.

It's... perfect. You ship caustic soda which is relative to other energy processes and carriers not all that dangerous (you don't need to store it pressured for example), cheap, extremely abundant to the desert, there you have a massive solar farm that turns into pure clean water and pure Sodium. That's even better than a hypothetical amazing Electrolyzer, because you _need_ water with those, whereas castner _makes_ water. I hear they can use that in the desert. Oh, and the anodes can be made from iron, which is cheap, easy, and abundant. Unlike the material you need to make your anodes from in state of the art water-to-H2 electrolysers!

Ship the sodium back. All you need is clean water. Toss a bucket of water at it and it poofs back into (Heat + H2 + caustic soda). Again, __perfectly__, no losses. You don't need a reactor or a catalyst or pressure; that process just goes automatically, all you need is a bucket and a vessel.

Storing sodium is, despite the youtube movies, easy. Some paper steeped in oil is all you need to wrap it in. It's stable under all 'warehouse temperatures' (-10 to +70), does not need pressure, and __has zero losses during storage__. It's also quite light.

Some back of the envelope math says that it's energy dense enough; a containership full of sodium contains more than enough energy to pay for the trip and then some - about as much H2 you can make with that as a ship with pressurized H2.

I'm guessing I must have messed up that math because this feels like it solves.. everything. Free energy for all. There's enough Sodium the world over, you can start right now (Sodium is already made in industrial quantities for other purposes, so you can just buy a containership's worth right away). Surely after 100 years of science we can improve on the already functional Castner Process. Solar panels are idiotically cheap and plentiful.

You can convert half the sahara, or the entire east coast of Spain, or the sun belt, into a giant solar farm, just ship coastic soda to it and sodium out. More energy than you'll ever need, and you solved the availability problem because you can store it, at no loss at all, effectively forever, at nearly no cost. Any warehouse can be converted into storage for peanuts.

I'd love to know what I'm missing here.