Zinc Bromine battery experiment

This is an experiment that I did with zinc bromide batteries. It is currently being studied for off-grid energy storage. Its discharge plate is uniform and smooth, keeping the power stable during the discharge. Its storage capacity depends on factors such as solubility and is best utilized using the flow configuration. Here I used gravity and then a miniature version just to watch the reaction.
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Este é um experimento que eu fiz com baterias do tipo zinco brometo. Ela é estudada atualmente para armazenamento de energia off-grid. Seu plateau de descarga é uniforme e suave, mantendo a potência estável durante a descarga. Sua capacidade de armazenamento depende de alguns fatores como solubilidade e é melhor aproveitada usando a configuração de fluxo. Aqui eu usei a de gravidade e depois uma versão miniatura somente para observar a reação.
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[@madeo8480]

I read some comments regarding bromine. They said that even carbon don't last long when exposed to it because it's so corrosive.......

[@danielrosselli]

Yes it is true, the corrosive environment is a fact, but there are some alternatives such as the use of some polymers that can be combined with carbons, and this greatly increases their durability.

[@dusteraa9804]

Check REDFLOW in Australia ... they have a commercial application frame that WORK

[@danielrosselli]

Cool! I will take a look!

[@dianekramer6467]

what ratios of sodium bromide an zinc sulphate did you use to make zinc bromide - I'm confused by hepathydrate vs mono hydrate

[@danielrosselli]

This video I did a quick experiment that I set up just to watch the reaction of this kind of batery, and I didn't make any notes. So I wanted to share the video because I thought it was interesting that the reaction happened and you can see the color change. This type of battery works very well, but it is logical that mounting the electrodes vertically makes this cell inefficient, serving only for testing purposes. A commonly used assembly for this type of battery is the "gravity", where the positive electrode is at the bottom, and works by the density of liquids.

[@Joekudi]

Hi any results for the energy density as well as efficiency?

[@danielrosselli]

Hi, this was an informal experiment that I did just to observe the reactions inside the glass. The voltage of these cells is around 1.8V. The efficiency of zinc bromide batteries are excellent, however they must be in the configuration of flow cells, that is, the electrolyte must be pumped over the electron collector. Flow cells are closely related to fuel cells, in fact fuel cells are primarily flow cells. You can see by looking closely at the zinc being electrodeposited, while the bromide is solubilized. That brownish color is it dissolving in the electrolyte. This type of battery is being studied for off-grid because it tends to support a large number of charge-discharge cycles without losing efficiency. One of the problems is the formation of zinc dentrites.

[@Joekudi]

@@danielrosselli ok thanks I hope to see some more on zinc bromine batteries...

[@zylascope]

@@danielrosselli I was told that this type of battery reduces zinc dendrites as the zinc will react with the bromine and turn back into zinc bromide solution. Do your experiments confirm that? Thanks for sharing.

[@edkoetsier339]

Hi Daniel Zinc should be at the top of the solution, just immersed in the Zinc Bromide, and the carbon electrode should be flat on the bottom, or better 2/3 down. Nothing survives forever in elemental bromine, not even carbon. I make 1.5 litre batteries. BTW, I really enjoyed your alkaline membrane video. Indeed, much cheaper than Nafion..

[@danielrosselli]

Hi Ed, thank for watching! I know this gravity type configuration. I've done one of these in the past but I didn't record it at the time. I want to make more video about it in the future because I like the performance of this type of battery. But I haven't used it for a long time to notice carbon degradation. Can you tell how long you lasted? I only remember at the time that I had problems with self-discharge. Why 2/3 of the bottom? Wouldn't it be better at the bottom because of the density of the bromine?

[@edkoetsier339]

@@danielrosselli You put the carbon 2/3 down to put it above the elemental bromine. The bromine forms on the carbon and drops down. Self discharge is caused by dendrite formation on the zinc, so you put the zinc away from the carbon as much as possible. A hunk of graphite or grafoil would decompose in weeks even in weak bromine 2/3 down. You will have to be more creative in you choice of carbon. Hint, HDPE linqstats. Remember the active material in this type of battery IS the electrolyte, as in all halogen batteries. Bigger IS better. electrolyte

[@danielrosselli]

@@edkoetsier339 HDPE is a good idea! I'll see if I can get some for future tests. Thanks for the tip. Doesn't self-discharge have to do with the fact that bromide comes into contact with zinc easily? In a flow configuration the bromide is outside the cell, this problem is solved. In gravity-type cells, bromide is diluted and in direct contact with zinc. In my old gravity cell, zinc had few dentrites and there was no short circuit, but it would still discharge if I let it rest. Did this happen to yours?

[@edkoetsier339]

@@danielrosselli All batteries self discharge to a greater or lesser extent. This battery does it a bit more than most but is not a problem if you use the power daily. These batteries have been used for 100 years and they are Very understood. Your comment about "must be configured as pumped flow" is wrong. Pumped flow is used to increase the energy density and nothing else. Anyone who makes a large quantity of these batteries must ensure that elemental bromine does not escape into the environment. I put my batteries on a wire shelf suspended suspended over a glass tank filled with activated carbon. If any battery breaks in the charged state, the bromine is captured by the activated carbon (which it is attracted to). Look at the 1905 patent. It has good ideas. Look at the 2015 Princeton patent, which failed or should have, they studied the energy density and self discharge.

[@rogerwilson6367]

I believe complexing agents are very important in these batteries to reduce self discharge. I think it reduces the vapour pressure of the bromine which is very important in something so volatile.