Author Archives: Peter

Thank you to Crowdfunding Supporters

Thank you to all of the kind supporters who helped raise money for undergraduate research in iron batteries here at the U of Idaho. Together we put together $5000 that will be put toward a fellowship and materials for a student to explore this and we will put together a open source plans document next year. We’re also going to document the process with a weekly video about the project, so please do stay tuned.

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Crowdfunding the iron age of batteries

I’ve launched a crowdfunding campaign to try to support a student in building an iron battery. I’ve got video up that talks about where we’ve been so far this year. We have had some success in building the battery and we’re moving to a better construction method.

We would like to test different cathode salts including a better test of potassium ferricyanide. We would also like to test different solvents such as a deep eutectic solvent and ionic liquid. The big, open question is the separator. We can try some natural gels, some in-house polymers and we can see if we can find a commercial polymer that is cheap and available enough to do the job.

I think it will be a great project for an undergraduate chemist with an interest in renewable energy. If you’d like to check out or share the campaign, the link is here:

http://c-fund.us/cg0

crystals of potasium phoaphate incorporating the chemical amaranth dye

Amaranth Potassium Phosphate Crystals

Potassium phosphate crystal chemistry

This weekend I grew some potassium phosphate crystals with amaranth dye. I did this back in 2001 in Bart Kahr’s O-Chem class and remembered it recently. It’s a fun demonstration of the chemistry of crystal growth, the different chemistry of the crystal faces, and it’s pretty. I found Prof. Kahr’s paper[1] that gives a “foolproof recipe” and it did not disappoint. Even this fool could make it work.

As the crystals grow, each face of the crystal has a unique topology. The corners are growing with a different spacing of atoms than the faces, and the faces can be different from each other. Sometimes, the faces have the right spacing to allow a dye molecule to stick. In this case, there is a big difference between how well amaranth dye sticks to each face. So as the crystal rows, it only gets dyed in two quadrants.

We can learn about chemistry from crystals

Crystals are super useful to chemists. A good crystal of a chemical can be used to get x-ray diffraction data on the structure of the chemical. The most detailed structures are derived from x-ray diffraction data.

Knowing how molecules assemble into crystals is also really important to materials scientists. If you want to design a material from its atoms, you need to know how they are going to come together. I’ve been working on making an iron battery and reading up on battery chemistry. One of the interesting papers I read talked about designing a cathode material to hold sodium atoms. The chemists designed the “holes” in the structure to hold sodium atoms – and they needed to know how the other atoms would come together to make that shape.

Why chemically dyed crystals are cool

Of course, dyed crystals just look cool. Maybe that’s silly, but if you’re trying to teach organic chemistry, it’s good to have something visual and striking to hold on to. A lot of O-chem is solvents and white powder, so anything that sticks in the memory is a help.

The other reason I think that dyed crystals are so cool is that they dyes can be held still very precisely. One of prof. Kahr’s later papers used a crystal to hold a fluorescent dye in place at a specific orientation. Then they used a fluorescence microscope to look at single dye molecules[2]. I think that’s just really cool. I gather that they are more stable in the crystal than they are in solution.

I also made a time-lapse movie of the crystallization

Instructions (following [1])

  • Dissolve 17 g potassium dihydrogen phosphate (KDP) in 50 ml water with heating. Using a teflon stir bar helps.
  • Dissolve 4 mg amaranth dye in ~1ml of water and add to the mix.
  • Pour into a wide dish and allow to cool and evaporate slowly over ~4-24 hours.

Sources

1.Kahr, B. & Vasquez, L. Painting crystals. CrystEngComm 4, 514–516 (2002). http://dx.doi.org/10.1039/B204845K

2.Wustholz, K. L., Kahr, B. & Reid, P. J. Single-Molecule Orientations in Dyed Salt Crystals. J. Phys. Chem. B 109, 16357–16362 (2005).http://dx.doi.org/10.1021/jp053051x

NORM 2017 Corvallis

I’m attending The Northwest Regional Meeting of the American Chemical Society in Corvallis. I just wandered around downtown. That was nice. My hope is to see some computational chemistry, commercialization, and nanoparticles tomorrow.

What tools are getting used for simulations? I’m especially interested in coarse-grained simulations of macromolecules. I see several Density Functional Theory talks and that should be interesting. Maybe folks from that world can point me in the right direction. Is anyone using tensorflow for such things?

There’s a panel on market-driven innovations. I would love to hear if people are funding academic labs through collaborations with industry. I feel like that would be a win-win, but I don’t know where to start there, either.

There’s also a bunch of analytical chemists giving MS talks and a “smart” nanoparticle talk. That’s just the morning session. I’ll have a hard time choosing.

If you’re in Corvallis and are reading this, do please shoot me a gmail (pballen). I’ll buy the first round at Tommy’s.

Negative and positive results in the quest for an all iron battery

Iron is cheap, and iron chemistry can be used to make a battery. If you want to buy a lithium-ion backup battery pack for a home solar system, it will cost as much as the solar panels. Effectively, a 24/7 solar system is about double the cost of a grid-tied system. The same is true for the grid itself. If the utilities want to move to cheap solar power, they will need to buy huge batteries. If utility companies tried this with lithium batteries, it would be such a big endeavor that it would mess with the lithium market. Iron is produced at such a huge scale that a move to grid-scale iron batteries wouldn’t completely alter the iron market.

I tried a dumb idea and it didn’t work. I tried to make an iron-oxide electrode for an iron battery. The idea was that iron oxide can be reduced to iron magnetite. That would be a cheap cathode for an all-iron battery. Plus, since iron oxide is a solid, it would stay where it was put and not diffuse over to the other electrode. So that would be nice, too.

Obviously (even to me at the time) iron oxide is an insulator, not a conductor. So if it is going to act as an oxidizing agent, it will need a path for electrons. Electrons can’t move through the iron oxide. They need to move through some other conductive material. So I embedded iron oxide particles in graphite.

2017-05-19 12_53_22-Krita

The result was nothing at all. The cell was dead on assembly. I could not detect the iron oxide reduction/oxidation with any instruments at my disposal. Other groups have reported the oxidation potential of the iron oxide nanoparticles. They put them in a suspension swirling near the electrode and that seemed to work. So maybe it’s possible, but I can’t get it to go. Iron oxide is out.

I made a better cell with Iron (III) EDTA as the oxidizing agent. It’s soluble so that makes things work better. I used a graphite felt as a current collector and it worked just great. The energy density is low (as expected) but it works.

2017-06-01 08_33_03-Krita.png

The next step is to optimize and stack up a bunch of cells. I think it’s getting close to being an “open source battery.”

I’ve been vlogging about this, if you want to watch progress in almost real time, have a look.