Flow Battery Research Collective

I'm no chemist, so this may not apply here, but I've been looking at info on different batteries. I looked at Nickel/Iron because of their known long life. One change mention from original Edison design is adding a little Lithium oxide or dioxide ( forget exactly) to the electrolyte To extend the life of the Iron electrode.

There was also something about making plates (instead of just using sheets of iron) using iron powder with carbon (for conductivity) and something else which I forget that reduced the production of hydrogen.

The battery looks interesting but has some problems. From what I've read, it tends to use up the water in the electrolyte fairly quick by splitting into hydrogen and oxygen. Also, It's working voltage is ~1.2v but it needs 1.6v (1.65v if added lithium) to take a change? The inverter I'm leaning towards now, GTIL2000, for low cost and simple connection has an input range of 45v-90v. When using a 48v LFoP battery, it only can produce about 1300w. With a 72v, it's around 1700w according post on a solar forum. One of these batteries with enough sells to put the charge voltage just below 90v with give me a battery that only has about 60v when no solar to charge it. That would really cripple the inverter.

Here is a few videos of someone messing with this battery making his own electrodes and a gell electrolyte in an effort to improve the battery.

https://www.youtube.com/watch?v=NaOzDt83XWY
https://www.youtube.com/watch?v=0mYaei0O1sU
https://www.youtube.com/watch?v=pjoxC4kwA9I

A lot of blabbering in this video on the Nickel/Iron Edison battery with lofty claims. So what is he not saying? How big does it need to be to provide useful power?

https://www.youtube.com/watch?v=cWBZNq8Q3Hs

https://www.youtube.com/watch?v=t09aBKUejSs&list=PLYDTEjzfnaSVHeUiCOX5Z9G7i_AiSifpR&index=10

https://www.youtube.com/watch?v=p2LaPcJia7U&list=PLYDTEjzfnaSVHeUiCOX5Z9G7i_AiSifpR&index=5

https://www.youtube.com/watch?v=fk_YEXZgQ8E&list=WL&index=12

Not that great, only 74% @ 1000 cycles

https://www.youtube.com/watch?v=i3Abqr1r-mk&list=PLYDTEjzfnaSVHeUiCOX5Z9G7i_AiSifpR&index=8

This guy did some videos for an all iron static battery. Here is the final version video and info page:

https://www.youtube.com/watch?v=0eK5ouP8hNQ&list=PLYDTEjzfnaSUe4u0WKlIXLqpL3VmYcrxv&index=2&pp=iAQBsAgC

https://www.hardware-x.com/article/S2468-0672(25)00007-0/fulltext

https://www.youtube.com/watch?v=GRumW9JzGbc
They are finding that Zinc batteries not only handle faster charging better, but it can even heal slow charging damage.

Just wondering, you are using water, but are you using distilled, or de-ionized, or just tap? The reason for the question is, when/if this becomes a doable project for home battery system, our tap water is very hard. It is a mix of ground water which is some what hard and CAP water which is water that has flowed for some 336 miles across the desert in an open canal diverted from the Colorado river making it VERY hard. Seems likely it would throw off the chemistry.

Don't know what you have there, but Target, Walmart, Home Depot, or even order from Amazon, Plastic storage bins. Just set the whole project in one. They come in clear so you can see in if there is a problem without removing the lid. If it spills, the fluid stays in the bin.

Maybe that is what the video was talking about when they said the biggest problem is ion lock, or maybe it was electron lock. But basicly it's very hard to get the charge out at a useful rate. I'm sure there is more to Tesla's secret sauce, but they said Tesla's fix was very thin aluminum with carbon pressed into it creating a battery that gave it's charge better, could be charged in 5 minutes, and produced far less heat then lithium batteries with no thermal runaway problem. It sounded like they won't even use battery cooling for it because what heat it does produce makes it work better. A lot of "sounds good", but will see when it hits the road.

@sepi It's the pressure difference that rupture the separator correct? So what I was talking about is some kind of double bypass valve (one for each side) that is linked together to keep the pressure the same on each side. Might be too complicated and likely yuo can already buy something like that though $$$. Anyway, just a thought.

Fuel injection works this way on cars. They use a bypass regulator to give you a smooth continuous flow. Pump is always pumping and extra goes back to the tank.

Another thought, someone might be able to come up with a regulator that balances each side. Pressure goes up on one side, it reduces that side and raises the other.

Question, what about using some sort aluminum oxide? Tesla is rumored to be using a new aluminum battery the developed in place of LFOP for the new model 2. They said something about aluminum holding 3 ions? per molecule instead of 1. I poked around and there are groups working on aluminum flow batteries. Seem they don't have the dendrite problem.

I see a number of groups working on aluminum flow batteries. Seems they don't have the dendrite problem.

Just a thought when using oversized pumps, try adding a bypass valve. With the valve fully open, the output of the pump just goes right back to the input. Close the valve a little at a time to get the pressure you want.

For a pointless waste of time search, I tried in google: "what is the best cheapest redox flow battery chemistry"
Came back with:

High-energy and low-cost membrane-free chlorine flow battery:
https://www.nature.com/articles/s41467-022-28880-x#:~:text=To meet the needs of,La France in 188428.

A high-energy and low-cost polysulfide/iodide redox flow battery:
https://www.sciencedirect.com/science/article/abs/pii/S2211285516304153#:~:text=Highlights * • The polysulfide/iodide redox flow,reversibility of polysulfide and iodide redox chemistries.

Air-Breathing Aqueous Sulfur Flow Battery for Ultralow-Cost Long-Duration Electrical Storage:
https://www.sciencedirect.com/science/article/pii/S2542435117300326

And 2 Google search options with a lot of results over my head:
Sulfur-Air Hybrid Redox Flow Batteries: https://www.google.com/search?num=10&cs=1&sca_esv=db6c98fd308e1745&q=Sulfur-Air+Hybrid+Redox+Flow+Batteries&sa=X&ved=2ahUKEwjS8bKDhoGPAxXpL0QIHXvhGwgQxccNegQIEhAB&mstk=AUtExfDy0ZazObNsltp9BYwtpQylX9u5AJT5yaQVQRbdARMJvJuEzcAf-Z2d4utwzTSnhCKcn4qOInT9b9zVkToTFJswogvnK4pun2X3x25KeDNW8dbrTS5jwMmIp6riqcFc6wG0Rm8FPMwC2B67TUxmok7FRMfFyfzTWq_Ub_BP2zY5rP4&csui=3

All-Iron Redox Flow Batteries: https://www.google.com/search?num=10&cs=1&sca_esv=db6c98fd308e1745&q=All-Iron+Redox+Flow+Batteries&sa=X&ved=2ahUKEwjS8bKDhoGPAxXpL0QIHXvhGwgQxccNegQIIhAD&mstk=AUtExfDy0ZazObNsltp9BYwtpQylX9u5AJT5yaQVQRbdARMJvJuEzcAf-Z2d4utwzTSnhCKcn4qOInT9b9zVkToTFJswogvnK4pun2X3x25KeDNW8dbrTS5jwMmIp6riqcFc6wG0Rm8FPMwC2B67TUxmok7FRMfFyfzTWq_Ub_BP2zY5rP4&csui=3

Google sure like long URL's

I was hoping there was something here. Lithium batteries cost way too much tripling or more the cost of a solar system and are way to dangerous with their high fire risk. But it really takes a battery to make solar worth doing because it averages out the load to make better use of the input even when not looking for extending through the night. I Just saw a 12kW split phase (we use 240 split phase in the US) hybrid inverter for under $500 which is cheep. Solar panels are also getting down if you look. But the battery is still a project killer.

I thought these were full flow batteries you guys were working on

But a .25kWh battery is hardly worth messing with. Need at least in the 10's of kWh. Last month we used 1271.84kWh (Summer time with record temps 110+) which comes to ~43kW/day. On 7/10/25 we used 47.36kWh.
And you can only collect during the day. Assuming an off the wall number of 30% of useable daylight, that leaves you needing to store ~25-28kWh for night.

I am confused, The big advantage of flow batteries is that the capacity is decoupled from the cells putting it in the size of the tanks. Need more kWh, use bigger/more tanks. Need more amp's, then you need more/bigger cells.

Oh, and solar with battery systems tend to use 48v because you need less amperage for a given amount of wattage.