My adventures building a Zinc-Bromine battery

danielfp248

Member
Joined
Aug 31, 2020
Messages
42
I've been thinking about starting an Instagram account to share pictures and stories about the fabrication of these devices and my experiments. Do you guys think this would be interesting for you? Let me know :)
 

vspin

New member
Joined
Aug 12, 2018
Messages
17
danielfp248 said:
I've been thinking about starting an Instagram account to share pictures and stories about the fabrication of these devices and my experiments. Do you guys think this would be interesting for you? Let me know :)

Yes, I'd definitely enjoy it. Although, I'm surprised even more people are not glued to this post.
 

danielfp248

Member
Joined
Aug 31, 2020
Messages
42
Thanks a lot for your support guys:D

I will probably start an Instagram account to share some additional visual with you guys pretty soon.

I just published a blog post about some issues I was having with cell stability when building spacer based cells (that have no separator) and how they were majorly fixed by going back to a metallic Zn anode. However, the question of dendrites is still there and higher PEG-200 concentrations or NaCl/NaBr additives are ineffective at preventing them at higher ZnBr2 concentrations. https://chemisting.com/2020/11/08/zinc-bromine-batteries-dendrites-adhesion-and-failure/
 

100kwh-hunter

Active member
Joined
Mar 2, 2019
Messages
698
I dont have Instagram or simulair nor even you-tube ect.
I would like it here on this forum....
Sorry for saying and i hesitated a real long time...realy long time to say this:
Start your experiments fresh with out any filer or what so ever, and make your cells higher, this would be the best bet...
So the zinc dendrites can have the space to form and the bromine can have the space to accumulate below.
The trick i think that would work is a conjunction between height and diameter, incl the surface of the electrodes.
Incl the simplicity of the chemicals.
You are adding a problem/barrier and solve it with a other problem...
When i had my 10cm/4inch high cell in 6cm/2.1 inch in dia all problems would seem to dispersal...
Remember i am also like you still learning..oke... in my primitive conditions.
I hate to write a negative comment, cous i can not think of one! inany of your work..So no negative things from here!

But please consider to rule out the fillers and just let it flow and with that flow take the losses for granted.
In my option the fillers are a dead track...no matter what fillers or fill in...
Again I did not meant to be rude...i greatly appreciate your work and afford.....A LOT!!!

The zinc dendrites is something you can not work around it, work with them, give them space, give the bromine space as well....

Sorry i had to get this of my chest, i really did not mean this negative, bud the track you are on, I think it is a dead one, forget fillers...
My one cent, sorry...
Btw i found a lost testing cell i build....after 5 months, it still holds 1.852v, but i dont remember if i charged it to the full?
Things that i consider as important: height and diameter of the cellsand no fillers...
The chemistry can be updated/enhanced for faster charging and discharging, but that is it...it has its limits.
Oke we/you level the path...now try tobuy in big volumes....that would be the next problem....not every country allows 1000kg of znbr2 to someones home(my country does allow btw).
I really hope you dont get this negative, those are just my thoughts and what i have learned with experimentation.

Soon i will have some time to experiment, i will keep you updated....Thanks in advance and keep going, i am following this with a lot of interested,

With best regards, Igor.
 

danielfp248

Member
Joined
Aug 31, 2020
Messages
42
100kwh-hunter said:
I dont have Instagram or simulair nor even you-tube ect.
I would like it here on this forum....
Sorry for saying and i hesitated a real long time...realy long time to say this:
Start your experiments fresh with out any filer or what so ever, and make your cells higher, this would be the best bet...
So the zinc dendrites can have the space to form and the bromine can have the space to accumulate below.
The trick i think that would work is a conjunction between height and diameter, incl the surface of the electrodes.
Incl the simplicity of the chemicals.
You are adding a problem/barrier and solve it with a other problem...
When i had my 10cm/4inch high cell in 6cm/2.1 inch in dia all problems would seem to dispersal...
Remember i am also like you still learning..oke... in my primitive conditions.
I hate to write a negative comment, cous i can not think of one! inany of your work..So no negative things from here!

But please consider to rule out the fillers and just let it flow and with that flow take the losses for granted.
In my option the fillers are a dead track...no matter what fillers or fill in...
Again I did not meant to be rude...i greatly appreciate your work and afford.....A LOT!!!

The zinc dendrites is something you can not work around it, work with them, give them space, give the bromine space as well....

Sorry i had to get this of my chest, i really did not mean this negative, bud the track you are on, I think it is a dead one, forget fillers...
My one cent, sorry...
Btw i found a lost testing cell i build....after 5 months, it still holds 1.852v, but i dont remember if i charged it to the full?
Things that i consider as important: height and diameter of the cellsand no fillers...
The chemistry can be updated/enhanced for faster charging and discharging, but that is it...it has its limits.
Oke we/you level the path...now try tobuy in big volumes....that would be the next problem....not every country allows 1000kg of znbr2 to someones home(my country does allow btw).
I really hope you dont get this negative, those are just my thoughts and what i have learned with experimentation.

Soon i will have some time to experiment, i will keep you updated....Thanks in advance and keep going, i am following this with a lot of interested,

With best regards, Igor.

Thanks for your post Igor :)I tried doing taller cells, the main issue with building taller cells with more space between the electrodes is the huge loss in energy efficiency that comes with it. The potential required to charge the cells increases dramatically due to this, going from a 3mm spacing to a 6mm spacing, there is already an almost 20% drop in the energy efficiency of the devices because of added resistance from the solution. Because of the conductivity limits of ZnBr2 solutions, high energy efficiency cells only appear possible with very short electrode distances (<3mm), this is corroborated by the commercial ZnBr2 products, which also use very short electrode distances.

I am curious about your setup though. How high was your energy efficiency? How many Wh could you get out for each Wh you could put in? With a cell with the geometry you describe, I would expect you to have energy efficiencies below 10-20%, meaning you would need to put in 10 Wh to extract 1-2Wh. Was this the case? What were the voltages you needed to charge your cells? Let me know!
 

Bubba

Active member
Joined
May 9, 2018
Messages
301
I thought I read somewhere that there flow cells that solved or at least delayed the dendrite problem and that is what they are doing on the larger scale commercial cells.
 

danielfp248

Member
Joined
Aug 31, 2020
Messages
42
Bubba said:
I thought I read somewhere that there flow cells that solved or at least delayed the dendrite problem and that is what they are doing on the larger scale commercial cells.

Flow batteries do not eliminate the dendrite issue, they often need periodic short circuiting through a shunt to make sure all dendrites are gone and prevent their long term buildup. They do account for them, minimize them and try to operate with them in mind though, this is indeed viable to a point at a large scale. However this is part of the reason why Zn-Br flow batteries have a low market share, as these dendrite issues create longer down time and increase operational costs. Besides this point, I personally want to explore static Zn-Br batteries, not flow batteries :D


I also recently posted my first results using Tween 20 + PEG-200 using fiberglass separators :D .https://chemisting.com/2020/11/13/zinc-bromine-batteries-peg-200-plus-tween-20-to-eliminate-dendrites-first-public-results-ever/
 

TimFr

Member
Joined
Sep 6, 2017
Messages
30

danielfp248

Member
Joined
Aug 31, 2020
Messages
42
TimFr said:
danielfp248 said:
Here is a blog post I just published discussing why the inverted architecture is likely necessary to get these batteries to work long term in a static configuration. https://chemisting.com/2020/11/25/z...erted-configuration-is-likely-more-practical/
This link does not seem to work.
Keep the good work up. I have supplies ordered to join the group search for the ideal battery


Works now



Great to have another person join! The most important thing in my opinion is to have a systematic approach to the problem, which means having an ability to reproduce and proper tools for device characterization.Being able to measure charge/discharge curves, quickly fabricate batteries of exactly the same dimensions and share results that others can learn from and reproduce is key if we want to make progress!
 

Jim Jr.

Member
Joined
Jun 3, 2018
Messages
63
Hello

I do not wish to make these type of batteries , but willing to possible help.

The most of the problem are similar to the metal plating industry , they want smooth even plated surface, no dendrites

They use:

1) A surface-cant similar to "Dawn dish soap " to make smaller H2 bubbles and so they do not stick to anything ( surface tension )

2) They hang every thing vertical or on a tilt to prevent H2 bubbles accumulating . (lead acid battery )

3) They use nonmetallic and metallic objects to steer the flow of metallic ions, Sharp corners are prone to ion flow increase -- to
more build up.

Opinion

Try polyvinyl alcohol , the lithium people use it (as a electrolyte carrier for the lithium salts) for an additive, than the Peg200


Good Luck with the project

JimJr
 

danielfp248

Member
Joined
Aug 31, 2020
Messages
42
JimJr. said:
Hello

I do not wish to make these type of batteries , but willing to possible help.

The most of the problem are similar to the metal plating industry , they want smooth even plated surface, no dendrites

They use:

1) A surface-cant similar to "Dawn dish soap " to make smaller H2 bubbles and so they do not stick to anything ( surface tension )

2) They hang every thing vertical or on a tilt to prevent H2 bubbles accumulating . (lead acid battery )

3) They use nonmetallic and metallic objects to steer the flow of metallic ions, Sharp corners are prone to ion flow increase -- to
more build up.

Opinion

Try polyvinyl alcohol , the lithium people use it (as a electrolyte carrier for the lithium salts) for an additive, than the Peg200


Good Luck with the project

JimJr

Thanks for the input Jim! Dendrites are no longer an issue, that was entirely solved by the use of 1% Tween 20 in solution, at least for ZnBr2 concentrations in the 1.5-3M range.
 

danielfp248

Member
Joined
Aug 31, 2020
Messages
42
Top