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You can also paint the outer plastic with an oil based paint that is impervious to CO2. This can allow you to prevent CO2 flowing into the cell through the housing without having to change the entire body.

More information about the DIY flow battery on my blog : https://chemisting.com/2024/03/15/an-open-source-diy-flow-battery/

If you are in the Neatherlands or close in the EU, we will be holding a free workshop in Eindhoven in April, it would be great if you can attend (https://www.eventbrite.com/e/flow4ubattery-event-pioneering-energy-storage-solutions-tickets-851447120257?aff=oddtdtcreator). We will be explaining...

I have given it a try, it definitely sucks at chemistry or I suck at prompting AI.

Sure, you can control dendrites this way and make your energy efficiency drop to 10% due to the omhic losses that happen. Whenever you hear people talking about solutions having the energy efficiency and coulomb efficiency data measured with their ideas is fundamental. Although Robert loves to...

The problem is not hurricanes. Even normal wind speeds are very problematic in these approaches. I would suggest watching these videos, which summarize a lot of the technical problems with this idea. Also note the titles of the videos are overly antagonistic for views, I don't view the idea as...

There are many problems with gravity batteries that use weights, in the context of towers it has never worked so far due to basically problems with keeping weights stable in the wind. The only viable trials up until now are using mine shafts, at least to the best of my knowledge. Water has...

Wherever you have the ability to pump large volumes of water and store them, this is definitely the best solution.

See this paper for a comprehensive comparison between Lithium Ion, Sodium Ion and flow batteries https://www.sciencedirect.com/science/article/pii/S0378775323008029

I don't think I will play with this backplated configuration anymore. It is too hard to make because basically any mistake in the entire assembly or any deterioration of the insulating coating means you will get dendrites that will short the battery. It is a very difficult to engineer approach...

Pure Fe batteries are great in that the Fe is extremely cheap. There are however two main issues with them (for me): 1. They need very acidic electrolytes (HCl 3M), which are unsafe to keep and use at my house. 2. They have extremely high levels of H2 generation, which makes their CE really...

Robert would have us believe everyone could be building 100 kWh batteries in their kitchens using 19th century technology. Sadly there are good reasons why those technologies never received massive adoption. I've always been critical of the lack of quantitative rigor and data in his videos...

Flow batteries are definitely better suited to 1. Flow batteries can have high CE and EE values (>95% and >90%) but those are much more costly to achieve. Currently such installations are at around 300 USD per 100 kWh, the lower EE ones using microporous membranes and none vanadium chemistries...

No, the surface area of the copper anode is indeed much smaller than the surface area of the felt, by a factor of perhaps a thousand or more. The felt is a very porous conductive solid, while the copper is a simple flat surface. The difference is that the zinc can deposit over zinc while iodine...

I repeated the entire process of building the pouch cell and tried charging it. The overpotential is now massive, even at a current of 0.4mA/cm2 the starting charging potential is already above 1.6V, at the same current density as the proof of concept cell the potential is 2.3V ? . In...

Sadly it was an epic fail ? Some of the nail polish peeled off and huge dendrites grew at the interface between the current collector and the PE. I likely need to do much more diligent cleaning of surfaces before applying the coatings.

Result of a single cycle on the "proof of concept" 1cm2 device. Charged to 25mAh. There was an abrupt loss of voltage at around 20mAh, so probably something unexpected happened. I will get this device out of the solution and take a look at how it evolved through this high SOC cycle. However no...

I have made a pouch design with the above structure to test a more realistic configuration. I made it with an area of 2.5cm x 2.5cm = 6.25cm2 using the same overall structure as shown before. Anode is made of copper and cathode is carbon felt over grafoil. The pouch and insulating separator are...

You cannot do felt on both sides as felt is not really good for depositing zinc. The Zn starts forming dendrites over the surface of the felt which actually can go all the way around with time since the felt is taller. With a flat metal electrode as anode the Zn deposits are actually much better...

Haha, I have tried only purple. About the grafoil. Both are part of the electrode. Although the grafoil is just the exposed current collector. The felt is needed as you need the surface area for the iodine to deposit on. The capacity of the cathode will be limited if the surface area is not...

This is a different device, not a flow battery but just a regular static battery. There is no membrane here. For updates on the flow battery please check out the flow battery thread!

I have done some first tests using the following architecture: Basically strips of copper tape are first placed on a square of PE sheet, then a copper tape disc (sanded to a clean surface) and grafoil strip are placed on the anode and cathode sides respectively. A carbon felt is then glued to...

Thanks for posting! Doing deep discharge cycles works to some extent but it doesn't really solve the problem fully.

With all my recent work in flow batteries in the Zn-I system, I decided to take a new look into Zn-I batteries. In particular a few new papers on back-plating of Zn exist, which is an interesting geometry solution to the problem of dendrite formation. I had never tried it before because I lacked...

Using a matter photo paper as a separator instead of daramic (https://chemisting.com/2023/09/23/a-zinc-iodide-flow-battery-using-a-matte-photo-paper-membrane/)

An important advantage of flow batteries over normal batteries in general is that all parts of a flow battery are serviceable and repairable, batteries always need to be scraped and disposed of when their life cycle is over. A flow battery might only require the replacement of specific parts but...

Robert is very good at making people interested in science and DYI things, but his numbers about efficiencies - given that he doesn't seem to measure actual cycling - are often plain wrong or poorly explained. A density of ~400 Wh/kg for these batteries is not true. The numbers in Li-Ion...

It depends on the levelized cost of storage. If you can store 75% for a very low lifetime cost, it definitely beats storing 0%. If you're losing the energy anyway, anything you store for a low cost is a big win. You're not storing energy you would have used, but energy you wouldn't have done...

I think this would make the most economic sense for off loading peak renewable production for same-day use, so for short term grid regulation operations.

For LiFePO4 the cost per kWh is still above 130 USD. It is definitely still too early to be talking about anything at large scale, but flow batteries - even at these lower energy efficiencies - can often make better sense than Lithium batteries. The 75% EE is only my first practical result, I'm...

15,000 catholye + 15,000 anolyte at 35Ah/L would give you 525kAh which at a mean discharge voltage of 1.23V would give you 645 kWh, this is 0.645MWh, so very massive system. At 1mL per cm2 of electrode area you would also need to have 1500 m2 of electrode area, which at a standard 25cmx25cm per...

We have also started a non-profit for the development of open source flow batteries (https://opencollective.com/fbrc). It is called FBRC (Flow Battery Research Collective). I started it with my colleague Kirk Smith and professor Sanli Faez...

For anyone who was interested in this thread, you might be interested in my new thread on Zn-I flow batteries https://diysolarforum.com/threads/my-adventures-building-a-diy-zn-i-flow-battery.69145/. This now includes actual experimental results of flow batteries I've built.

After all the adventures trying to build the Mn-Fe flow battery, I have now shifted to a Zn-I flow battery. Since I now have a full setup to actually test flow batteries, I have arrived at this chemistry after testing several other alternatives. You can see some of my experimental results on my...

I have been doing some preliminary studies using the Fe-EDDHA/Mn-EDTA system using my current flow battery setup. So far it seems that it won't be a viable solution for DIY. I have written a blog post detailing some of the problems...