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Hi Guys, My name is Daniel, I am a chemist with a passion for battery technology and currently trying to build a highly efficient Zinc-Bromine battery at home using readily available materials. I have a blog where you can follow my progress (https://chemisting.com/). I am using a DIY USB...

Finally, Exp30 reached 1000 cycles ???. No dendrites, almost no capacity loss. The test has now been stopped and restarted at 1.290mAh of capacity (more than double current capacity) to see how the battery behaves.

I have decided to start doing some experiments to create a Mn/Fe flow battery. I will post links to blog posts on this thread as I write them. https://chemisting.com/2022/11/17/towards-a-diy-manganese-iron-flow-battery-first-experiments-using-cyclic-voltammetry/ Questions are welcome.

Welcome to my adventure building a Zinc-Iodine battery All experiments carried out from #100 are now shared publicly (https://www.dropbox.com/sh/67hdgpm5lijt5s1/AACS0gjDSYHZny_tLSfXXmfza?dl=0). The experiment_summary excel file contains a summary of all important variables in the experiments...

So, I read an article that came out last year that went deep into the characterization of these Mn/Zn systems and the effect that mildly acidic conditions and pH buffers have on the formation of MnO2 oxides and their charging/discharging behavior...

After looking at Zn-halide chemistries and running into big road blocks with both Zn-I and Zn-Br batteries, I have decided to explore the world of Zn-MnO2 batteries. Especially, mildly acidic rechargeable Zn-MnO2 chemistries. These batteries use very earth abundant elements and very low cost...

This is Exp21, using CCP cathode, 3 layers of fiberglass separator, copper anode and the regular ZnCl2 15m + KI 5m electrolyte. This cell is being cycled between 0.8V and 1.275V at 10mA/cm2. So far 100 cycles and the battery capacity went down and then back up close to max capacity. I...

The battery ran for 222 cycles. Decay became significantly more pronounced during the last 30 and the stability in the potentials was only temporary, there were also some small dendrite issues. So far this is the battery I have cycled for the longest yet.

The first WiS (water-in-salt) battery I constructed dried due to some air openings in my Swagelok cell. I added teflon tape to the electrodes to provide a tight seal and prevent contact with the outside environment. I then made a second WiS Zn-I device per the description in the post linked in...

I wanted to see how high the capacity could get for the battery in #19. I managed to charge it to 25mAh, capacity was 14.8mAh. CE 59%, EE 44% on first cycle. This takes the density to 29Wh/L.

I have watched all of Robert's videos, I even decided to pay to become a member of his community to get access to several extra videos about this topic not available to the general public. The videos have not been very useful though, mainly because of the following reasons: While Robert shares...

I then created a battery using my Swagelok cell and the 1.5M ZnI2 electrolyte. I used 10 layers of fiberglass separator, a GFE-1 cathode and graphite electrodes. The battery was charged to 5mAh and discharged to 0.6V, both at 15mA (11.6mA/cm2). CE=72%, EE=64% on first cycle. Average charge...

Here you can see the exact same battery charged/discharged at 0.5 mA. With a low current I can charge it to an even higher capacity (500 uAh) with a higher Coulombic efficiency (94%). The lower current means that only the most favored reactions at that potential will happen and ions will be able...

New record, Exp30 is at 358 cycles so far. No dendrites yet.

I am now repeating Exp12 - the longest lasting yet at 222 cycles - but using a Zn anode instead of a Cu anode to see what effect this has. All other variables are exactly the same.

I ran Exp30b for 32 cycles, no problems happened. I am now going to double the discharge capacity again, to 2.580 mAh, and see what happens. This will be Exp30c. Note all of these Exp30 runs are using the same battery - I haven't taken it apart - so I am basically now pushing it to failure, to...

No, I moved countries again. This time I moved from Colombia to Spain, so I had to leave all my battery experiment stuff in Colombia with family. I will hopefully get the electronic and electrode parts back when they come to Spain later this year.

So guys, I moved countries earlier this year and hadn't had the time to start my home-research into Zn-Br batteries again. However, I have now reached a stable situation and will start researching Zn batteries again. I will start another thread as I will start research into some additional Zn...

I ran the battery for 46 cycles of charge to constant capacity at 3mAh at 15mA: Capacity held for around 30 cycles, then there started to be some evident loss of capacity. It seems that the battery cannot be reliably charged/discharged at 15mA, internal resistance starts to increase too much...

Test experiment running 1m ZnSO4 + 1m MnSO4 + 10% acetic acid pH 5 buffer (adjusted with from acetic acid with potassium carbonate). Anode is Zn metal foil, cathode is CC Carbon cloth. Separator is 3 layers of fiberglass filter. Charging to 0.5mAh at 5mA, discharging to 0.8V at the same current.

Exp27 is marking a new record for stability, so far 301 cycles and counting. Virtually no deterioration in capacity so far. CE at 96%, EE at 51.4%. Energy density is quite low due to the thicker separator, currently around 3Wh/L. If it remains stable we can then think about cycling to higher...

After 3 cycles. Last cycle CE=89.96%, EE=80.04%.

Exp30 is now at 673 cycles. No dendrites yet. In the charge/discharge curves below I am only plotting 1/10 so that the plot is readable. Other graphs do contain all points. No appreciable capacity or efficiency loses yet.

Exp12 is giving some really interesting results. It uses a copper anode, a Spectracarb 2050A-0850 Cathode, 3 layers of fiberglass separator and an electrolyte made of 15m ZnCl2 + 5m KI + 1m NaCl in distilled water. I am testing this at a current density of 10mA/cm2, charging to 1.45V and...

I was finally able to take a ZnI2 battery to charge to 15mAh, which gives me an energy density of around 20Wh/L. The battery was charged at a current of 20mA and discharged to 0.6V. Battery was made of a GFE-1 cathode, 10 layers of fiberglass separator, and a graphite anode. The electrolyte is...

That test didn't last for long, cell died pretty quickly (12 cycles). I am now doing a test (Exp31), with the newly prepared MnCl2 solution, to create a 2m MnCl2 + 4m ZnCl2. As expected, this time the electrolyte had zero precipitates upon preparation, due to the complete absence of sulfates. I...

Exp 28 after 50 cycles. Capacity and CE stability continue to be amazing compared to previous batteries. Charge/Discharge potential changes were quite drastic in the beginning but are also beginning to stabilize.

I finished preparation of my MnCl2 solution from MnSO4+CaCl2. The precipitate was hard to filter - as CaSO4 has quite fine particle size - but in the end I was able to obtain the solution as planned. The density of the solution was 1.428 g/cm3 (measured with a pycnometer) which gave me a final...

These are some curves I just measured at a higher current (5 mA/ 1.3cm^2) vs the 1 mA I usually use. The resistance of the conductive HDPE is also so high that to increase the current, the potential needs to increase a ton and a lot of energy efficiency is lost. The coulombic efficiency is still...

Systems of this sort will generally do 20-40Wh/L, so a 125gal tank of catholyte + 125gal tank of anolyte could give you ~30kWh of storage. However, there are currently no commercial systems that work with earth abundant chemistries at safe pH values for lay people. The only commercial setups so...

After 5 cycles at 1.5mAh you can see how stable potentials and efficiencies are when you pre-generate the MO2 and don't go to high potentials on charging. Mean charge potential is 1.7V.

After 440 cycles, no dendrites yet in Exp30. Capacity is still stable.

First cycle of the glass separator WiS battery. I used four layers of fiberglass separator and an HB-1070 cathode. Charged to 1.35V, discharged to 0.5V at 5mA. CE = 87.9%, EE = 80.73%, Thickness = 0.055cm, Diameter = 1.29cm2, Energy Density = 30.43Wh/L, Mean Discharge Potential = 1.27V.

Exp33, after 30 cycles. Everything is still stable. (failed after 32 cycles due to dendrites, note the cell was ran vertically - anode at the bottom - as in the 1000 cycle experiment)

I'm happy to do so! Thanks for all your support.

I ran 15 cycles for the battery described in #6, charging to 5mAh at 15mA. These are the results: There was very slight deterioration of potentials and capacity, but so far no catastrophic failure or large deterioration of CE or EE. So far, no zinc dendrites either. I am now going to cycle...

The battery in #19 did not last too long under these conditions, with evident mounting damage as a function of time. With the low CE (<60%) a lot of side reactions were likely happening in the battery which led to strong capacity loss as a function of cycle number. This battery has been a...

Exp28 is evolving nicely. The 4m ZnCl2 + 2m MnCl2 is generating much more stable curves at a much higher starting CE (already close to 96%) and a record EE for my Zn-MnO2 batteries of 55-56%.

I cycled 25 times to 15mAh, no problems at all: I have decided to stop cycling at this point and run a "max capacity" experiment. I am going to charge the battery to 2.1V, see how much charge I am able to store and how much I can recover, test the limits of the battery's energy density.

I also wanted to point your attention to one of the previous results. When I forced charging to 3mAh on a battery with the original ZnCl2+KI electrolyte (#45). Notice how in cycles where the charging potential went very high - above 1.6V - we actually got some discharge at the 1.6V level. This...

Charging to 10mAh I do see a sharp decrease in CE and EE, which are now 60% and 50% respectively. I believe this is because of the presence of only ZnI2 in the solution. When I oxidize a lot of the Iodide into elemental Iodine, there is a lot of free Iodide available to form polyiodides that...

Plot of all cycles together so far for this battery (13). I coded this plot so that more recent curves are plotted darker. Notice how we have no issues due to dendrites so far.

Exp25 showed substantial improvements, basically no large changes in capacity up until failure due to dendrites, better CE (~92%) and EE (~50%). However, dendrites were mainly present on Zn anode edges and some crystals - presumably Na sulfate - were also present at electrode edges. The...

Exp30b has now more than doubled the discharge capacity, the CE is at 87% and the EE is at 52%. Charging and discharging at 10mA/cm2, charging to 1.29mAh, discharging to 0.0V. So far, 12 cycles, no sign of dendrites.

All the experiments were showing shorts quickly after running at either 2.5 or 5 mA. I tried several different concentrations of Tween-20 and cetrimonium chloride with no difference in shorting. However I had previously ran cells with 15m ZnCl2 + 5m KI in distilled water for long times without...

Charging at 5mA to 500uAh, then discharging at 5mA to 0.5V. So far so good. Last cycle CE=95.24%, EE=67.51%

I just published a blog post (https://chemisting.com/2020/09/12/zinc-bromine-batteries-can-they-really-be-that-good/) discussing the results in this paper (https://www.sciencedirect.com/science/article/pii/S2589004220305356#mmc1) and how the published specific capacity/energy/power values for...

So far I've been able to cycle the battery 9 times at 1mAh. I discharged to 0.8V. The discharge capacity is up to 0.90mAh, with a discharge potential of 1.42V this gives me an energy density of around 13Wh/L. The CE, EE and capacity are all stable so far. The EE>70% and the CE>90%.

I just assembled a battery using a CCP cathode, a Whatman 42 filter separator, a zinc anode and an electrolyte using 19m ZnCl2 + 5m KI in white vinegar. I want to see the effect of a higher ZnCl2 concentration, as I am probably using a lower purity ZnCl2 compared to that used in the article. I...

After 107 cycles there are no signs of degradation (the small drop at cycle 65 was because my computer restarted and I had to restart the testing process). Both charge and discharge potentials have started to stabilize. The battery has a CE > 95% and EE > 80%.