An inexpensive alternative to lithium-ion batteries for energy storage

[Scout26]

If I remember correctly from my work with Hazmat, inhaling Hexane eats through your brain.  When it doesn't just explode outright.

And sodium and water do not play well together.  IIRC, it's worse then lithium in the burns/explodes in water trick. 

[Firethorn]

If I remember correctly from my work with Hazmat, inhaling Hexane eats through your brain.  When it doesn't just explode outright.

And sodium and water do not play well together.  IIRC, it's worse then lithium in the burns/explodes in water trick. 

Reading the article, they're not asking the end user to add a little to their batteries like topping off lead-acid with a bit more water.

It's adding a little to the anode/cathode construction, which presumably prevents them from sucking all the sodium out of the electrolyte, which was seriously limiting battery life previously.

While not ideal, we can handle hilariously dangerous chemicals during a manufacturing process when necessary.

[Scout26]

Reading the article, they're not asking the end user to add a little to their batteries like topping off lead-acid with a bit more water.

It's adding a little to the anode/cathode construction, which presumably prevents them from sucking all the sodium out of the electrolyte, which was seriously limiting battery life previously.

While not ideal, we can handle hilariously dangerous chemicals during a manufacturing process when necessary.

Yes, I understand that.  However, a little hexane in a lot of batteries=a lot of hexane.  And sodium still gets all explodie with water. 

[RocketMan]

Yes, I understand that.  However, a little hexane in a lot of batteries=a lot of hexane.  And sodium still gets all explodie with water.

From my reading of the article, the hexane is used in fabricating the sodium powder, and possibly as a transport mechanism. Does it actually remain in the battery after manufacturing, or does it evaporate after it transports the sodium powder onto the battery components?  The article was not entirely clear on the process.

[zxcvbob]

Yes, I understand that.  However, a little hexane in a lot of batteries=a lot of hexane.  And sodium still gets all explodie with water. 

I think hexane is a major component in gasoline.  It's not particularly toxic and it's not explosive, although it is quite flammable (like gasoline)  Sodium is really not much worse in water than lithium.

But I thought sodium batteries had to operate at high temperatures.  Maybe that's some kind of liquid sodium battery instead of sodium ion.  Or I'm misremembering something else sodium.

[Firethorn]

From my reading of the article, the hexane is used in fabricating the sodium powder, and possibly as a transport mechanism. Does it actually remain in the battery after manufacturing, or does it evaporate after it transports the sodium powder onto the battery components?  The article was not entirely clear on the process.

My reading, it is used as a suspension.

So Pol and his team looked to make some tweaks. Using standard ultrasound technology, they melted chunks of sodium down into a milky purple liquid, which they in turn cooled into a powder and suspended in hexane solution, leaving an even spread of powder particles.

Adding just a few drops of this powder material during fabrication of both the anode and cathode electrodes brought much better results. Pol tells us they observed much longer charging and discharging cycles, along with better coulombic efficiency (the efficiency of charge transfer).

And the problem:

One of these is a short life due to the congregation of sodium ions at the electrode made from carbon, called the anode, during the first few charging cycles. Here they build up and form what is known as a solid electrolyte interface, which hungrily eats up the sodium ions and before long, leaves a busted battery.

Given "a few drops", it's a method of doping the electrodes, and the hexane, C6H14, would dissolve into the electrolyte if it is still around.  How it does its chemical magic I don't know.  C6H14 isn't going to be hilariously toxic either.  

From wiki:

The acute toxicity of n-hexane is rather low, requiring grams per kilogram. Inhalation of n-hexane at 5000 ppm for 10 minutes produces marked vertigo; 2500-1000 ppm for 12 hours produces drowsiness, fatigue, loss of appetite, and paresthesia in the distal extremities; 2500–5000 ppm produces muscle weakness, cold pulsation in the extremities, blurred vision, headache and anorexia.[14] The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) for hexane isomers (not n-hexane) of 100 ppm (350 mg/m3 (0.15 gr/cu ft)) over an 8-hour workday.[15]

Basically, it's used as a component in a lot of glues, for degreasing, and other tasks.  Given the expected reaction of sodium powder to anything with water in it, this sounds like about as safe of an alternative as practical.

zxcvbob - these seem to be "salt" batteries, using a sodium ion, not a pure metal sodium battery.  IE "salt water".

https://en.wikipedia.org/wiki/Salt_water_battery

vs

https://en.wikipedia.org/wiki/Sodium%E2%80%93sulfur_battery

[charby]

Yes, I understand that.  However, a little hexane in a lot of batteries=a lot of hexane.  And sodium still gets all explodie with water. 

We also have NG or Propane going into many of our houses, how many houses blowup each year from that.

[Fly320s]

We also have NG or Propane going into many of our houses, how many houses blowup each year from that.

Well, in Boston.... a few more than normal this year.

[Brad Johnson]

zxcvbob - these seem to be "salt" batteries, using a sodium ion, not a pure metal sodium battery.  IE "salt water".

Salt water? Salt water!?? YER GONNA YOOZ UP DE OSHINS!!!

Brad

[Hawkmoon]

While not ideal, we can handle hilariously dangerous chemicals during a manufacturing process when necessary.

There used to be a company in the next town that thought that.

Note that I used the past tense in referring to the company. We use the past tense in referring to their [former] building, too.

[Fly320s]

Sumdood once said that matter can not be created or destroyed, so that building still exists.  Somewhere.  Sort of.

[Scout26]

There used to be a company in the next town that thought that.

Note that I used the past tense in referring to the company. We use the past tense in referring to their [former] building, too.

There used to be the skeletal frame of a 10 story building (demolished a few years back) along I-90 near Rockford that used to have windows and sides.  IIRC, it was a foreign firm (Japanese or Chinese, I disremember), that either forgot to do the morning safety brief, or the new guy missed a step.  Anyway, the building was rapidly air conditioned and turned it into a convertible one day.    Not sure what they mixing/making, but they had a "Rapid Deconstruction Event".

http://www.journalstandard.com/article/20150311/news/150319829

[zxcvbob]

There used to be the skeletal frame of a 10 story building (demolished a few years back) along I-90 near Rockford that used to have windows and sides.  IIRC, it was a foreign firm (Japanese or Chinese, I disremember), that either forgot to do the morning safety brief, or the new guy missed a step.  Anyway, the building was rapidly air conditioned and turned it into a convertible one day.    Not sure what they mixing/making, but they had a "Rapid Deconstruction Event".

http://www.journalstandard.com/article/20150311/news/150319829

That could have just been a steam boiler.  The news reports match one of these: https://en.wikipedia.org/wiki/Boiling_liquid_expanding_vapor_explosion

[just Warren]

https://www.technologyreview.com/s/612351/top-battery-scientists-have-a-plan-to-electrify-flight-and-slash-airline-emissions/