My build (very slowly progressing)
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After my flasks have arrived, I was finally able to mix the electrolyte tonight. I'm a bit surprised by the "recipe" producing only short of 10ml. Is this enough or is it meant to be scaled up for usage in the battery?
I was also wondering how to properly do this in a non-lab setting. How do you clean your glassware before and after use? Can I use regular tap water and clean with paper towels?
I collected the waste water used for cleaning (the first rinse) in a PP bottle. Should I give it to the special waste facility that also handle old batteries and paint for disposal? Do they need to know what it is?
Also, how precise do I need to be? I got a new precision scale and tried being accurate to the third digit but I wonder how important this really is.
Can I just pour water over the mixed salts or should I do it the other way around. I have this vague idea that the first way might be dangerous, or is this only with acids?
Anyways, I bow have a tiny amount of slightly yellowish liquid eagerly waiting to be put to use. Do I need to store it in special conditions except for a closed vial? Does it degrade quickly? Also how badly do the reagents themselves degrade? IIRC, the zinc chloride was extremely hydrophillic (I guess it's not the hydrated form), is it fine to leave the container open for a minute or two?
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After my flasks have arrived, I was finally able to mix the electrolyte tonight. I'm a bit surprised by the "recipe" producing only short of 10ml. Is this enough or is it meant to be scaled up for usage in the battery?
I was also wondering how to properly do this in a non-lab setting. How do you clean your glassware before and after use? Can I use regular tap water and clean with paper towels?
I collected the waste water used for cleaning (the first rinse) in a PP bottle. Should I give it to the special waste facility that also handle old batteries and paint for disposal? Do they need to know what it is?
Also, how precise do I need to be? I got a new precision scale and tried being accurate to the third digit but I wonder how important this really is.
Can I just pour water over the mixed salts or should I do it the other way around. I have this vague idea that the first way might be dangerous, or is this only with acids?
Anyways, I bow have a tiny amount of slightly yellowish liquid eagerly waiting to be put to use. Do I need to store it in special conditions except for a closed vial? Does it degrade quickly? Also how badly do the reagents themselves degrade? IIRC, the zinc chloride was extremely hydrophillic (I guess it's not the hydrated form), is it fine to leave the container open for a minute or two?
Congratulations on getting all the chemicals needed!
@sepi Let me answer your questions:
After my flasks have arrived, I was finally able to mix the electrolyte tonight. I'm a bit surprised by the "recipe" producing only short of 10ml. Is this enough or is it meant to be scaled up for usage in the battery?
When we run battery experiments we generally only run 5mL per side, 5mL on the catholyte side and 5mL of the anolyte side.
I was also wondering how to properly do this in a non-lab setting. How do you clean your glassware before and after use? Can I use regular tap water and clean with paper towels?
Clean with tap water, then clean with alcohol or acetone, then clean with a paper towel.
I collected the waste water used for cleaning (the first rinse) in a PP bottle. Should I give it to the special waste facility that also handle old batteries and paint for disposal? Do they need to know what it is?
This depends on your local regulations, you should contact your local authorities to see what they require. You can precipitate everything in the solution by adding Cu carbonate (mainly potassium chloride would be left in solution), the insoluble solids can then be disposed of more easily. Storing solids is also easier as they occupy less space.
Also, how precise do I need to be? I got a new precision scale and tried being accurate to the third digit but I wonder how important this really is.
Preparing the salts to +/-0.1g should be precise enough.
Can I just pour water over the mixed salts or should I do it the other way around. I have this vague idea that the first way might be dangerous, or is this only with acids?
For these amounts this is fine, for larger amounts (10x this), adding the salts to water would be more desirable.
Anyways, I bow have a tiny amount of slightly yellowish liquid eagerly waiting to be put to use. Do I need to store it in special conditions except for a closed vial? Does it degrade quickly? Also how badly do the reagents themselves degrade? IIRC, the zinc chloride was extremely hydrophillic (I guess it's not the hydrated form), is it fine to leave the container open for a minute or two?
It needs to be stored in an airtight container as the iodide in solution will react with atmospheric oxygen, it will turn yellower and then red as this happens. You can put a strip of metallic zinc inside the solution to better preserve it. About the ZnCl2, it is very hygroscopic, so you should open this container for as short of a time as possible. I try to weigh it in less than 20 seconds to introduce as little water as possible from the air.
Please remember to wear proper PPE when doing all of these experiments and make sure you do so in a place that's well ventilated.
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@danielfp248 Thanks for the quick and thorough answers! You should add those points to the docs unless you feel that this might potentially create legal trouble.
About the PPE, I was wearing nitrile gloves, cotton work cloths and plastic safety glasses (not closed though). I felt reasonably safe
About the copper carbonate for precipitation, would that be the natural one or basic one? Since I'm curious and want to bring my chemistry skills up to date: how do you know that this will cause precipitation? Is this compound used frequently for precipitation? Is this about chemical potential of copper iodide (s) and zinc carbonate (s) being lower than the sum of their respective ions (aq) in solution?
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@danielfp248 Thanks for the quick and thorough answers! You should add those points to the docs unless you feel that this might potentially create legal trouble.
About the PPE, I was wearing nitrile gloves, cotton work cloths and plastic safety glasses (not closed though). I felt reasonably safe
About the copper carbonate for precipitation, would that be the natural one or basic one? Since I'm curious and want to bring my chemistry skills up to date: how do you know that this will cause precipitation? Is this compound used frequently for precipitation? Is this about chemical potential of copper iodide (s) and zinc carbonate (s) being lower than the sum of their respective ions (aq) in solution?
@danielfp248 Thanks for the quick and thorough answers! You should add those points to the docs unless you feel that this might potentially create legal trouble.
I think we can add these as reasonable guidelines, we will include clarification that waste disposal should always be consulted with local regulations though.
About the PPE, I was wearing nitrile gloves, cotton work cloths and plastic safety glasses (not closed though). I felt reasonably safe
That seems adequate, especially if adequate ventilation is also in place. The quantities are small, so hopefully this also reduces the risk.
About the copper carbonate for precipitation, would that be the natural one or basic one? Since I'm curious and want to bring my chemistry skills up to date: how do you know that this will cause precipitation? Is this compound used frequently for precipitation? Is this about chemical potential of copper iodide (s) and zinc carbonate (s) being lower than the sum of their respective ions (aq) in solution?
This is because Zn carbonate and Cu iodide are insoluble so a double displacement reaction occurs and both fall out of solution. There is an additional complication in that Cu+2 does oxidize I- to elemental I2, so you will also have some solid iodine formation. What precipitates is actually Cu(I) iodide. You can add some Na thiosulfate if you want to make sure all iodine precipitates as copper (I) iodide.
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So I have gotten my pumps, off course they are the wrong ones, the brushed version and not the brushless. This creates problems since I can't easily adjust the RPMs. I instead got some c+eap PWM H-Bridge drivers to at least have some open loop control. Using this setup, I managed to do my first leak testin. As expected my homemade barbed tube connectors were not all tight and the cell leaked too. I'll try again without the connectors I added for easier cell removal. After having tightened the cell quite a bit, I think it os tight. This would need to be tested again with the aforementioned setup. So my buimd has slowed down considerably due to lack of time, but it hasn't halted :).
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After installing tubes without my homeprinted barbs for easy removal, I managed to get the system running without a liquid leak. I've had it run for 5min with no visible leak but will let it run for an hour or so to make sure.
On the negolyte side, there is however some fizzing to be seen in the tank, also when I place the septum on the right tank, at some point it will pop off. There is thus a gas leak somewhere. Do you have a good strategy how to find this @danielfp248 @kirk ? I guess it's in the part where the liquid is sucked out of the cell and into the pump.
I managed to fix an issue with one pump running quite a bit slower than the other with equal voltage applied. I managed to trace the issue back to one for the gears in the planetary gearbox being slighly misplaced. Has anyone had those issues yet? After making sure all gears are inserted perfectly symmetrically, both pumps run pretty smoothly and less hot.
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So I have gotten my pumps, off course they are the wrong ones, the brushed version and not the brushless. This creates problems since I can't easily adjust the RPMs. I instead got some c+eap PWM H-Bridge drivers to at least have some open loop control. Using this setup, I managed to do my first leak testin. As expected my homemade barbed tube connectors were not all tight and the cell leaked too. I'll try again without the connectors I added for easier cell removal. After having tightened the cell quite a bit, I think it os tight. This would need to be tested again with the aforementioned setup. So my buimd has slowed down considerably due to lack of time, but it hasn't halted :).
@sepi said in My build (very slowly progressing):
I have gotten my pumps, off course they are the wrong ones,
Oh shoot, that's annoying, I'm sorry to hear but they will still allow you to test.
@sepi said in My build (very slowly progressing):
I managed to get the system running without a liquid leak.
Awesome progress!
@sepi said in My build (very slowly progressing):
After making sure all gears are inserted perfectly symmetrically, both pumps run pretty smoothly and less hot.
This is a good catch, I had this happen once when I manually swapped the tubing out.
@sepi said in My build (very slowly progressing):
After more than an hour, the negolyte tank almost overflowed and the posolyte one was almost empty. This seems weird to me because both pumps seem to run at the same RPM.
This sounds like internal leakage through/around the membrane or similar, or some type of flow obstruction in one flow path that is causing higher pressure on one side of the membrane and bulk fluid transfer from one side to the other. The pressures on each side of the cell should be roughly matched, total imbalance in an hour is too fast. All your printed parts seem to have clear internal flow channels?
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@sepi said in My build (very slowly progressing):
I have gotten my pumps, off course they are the wrong ones,
Oh shoot, that's annoying, I'm sorry to hear but they will still allow you to test.
@sepi said in My build (very slowly progressing):
I managed to get the system running without a liquid leak.
Awesome progress!
@sepi said in My build (very slowly progressing):
After making sure all gears are inserted perfectly symmetrically, both pumps run pretty smoothly and less hot.
This is a good catch, I had this happen once when I manually swapped the tubing out.
@sepi said in My build (very slowly progressing):
After more than an hour, the negolyte tank almost overflowed and the posolyte one was almost empty. This seems weird to me because both pumps seem to run at the same RPM.
This sounds like internal leakage through/around the membrane or similar, or some type of flow obstruction in one flow path that is causing higher pressure on one side of the membrane and bulk fluid transfer from one side to the other. The pressures on each side of the cell should be roughly matched, total imbalance in an hour is too fast. All your printed parts seem to have clear internal flow channels?
@kirk said in My build (very slowly progressing):
This sounds like internal leakage through/around the membrane or similar, or some type of flow obstruction in one flow path that is causing higher pressure on one side of the membrane and bulk fluid transfer from one side to the other. The pressures on each side of the cell should be roughly matched, total imbalance in an hour is too fast. All your printed parts seem to have clear internal flow channels?
That could be the culprit. When I finally find some time, I'll check if I can blow through the flow frame. An obstructed manifold would indeed explain why or gets sucked into the tanks. Thanks for the diagnostics!
