My idea comes from a practice that is common with "HHO" electrolysis projects. An electrolysis cell is basically nothing more than an electrolytic capacitor with slightly too much voltage being applied, causing it to break down the electrolyte. However, electrolysis is still limited to just slightly more voltage than an electrolytic capacitor, i.e. 1.2-2 volts. But you can see in the picture that 12 volts is being applied. This is because the cell contains "floating plates" (blue in the diagram). The floating plates are not connected to anything, but the electrolyte brings power to them, converting them into active electrolytic plates. So as a result of the floating plates, the voltage between any two plates in the diagram is only 2 volts.

The second part of my idea comes from the fact that a floating plate does not really need to be electrically contiguous. People have successfully used screens as plates, once the screen becomes electrically charged, the electrons don't just "go through the holes". Furthermore, if the screen were broken into parts and some part was not electrically charged, then it's a conductor, which makes it a better path than passing through the electrolyte.

So if the floating plates do not need to be connected to anything, and they do not even need to be large contiguous objects, then there's no reason why you couldn't use a slurry of metallic particles suspended in the electrolyte and let them self-organize into "virtual" floating plates.

This is the foundation of an idea which I'm calling The Mud Cap.

To be continued more...

Here's my idea:

In a pot that is near 200C, create a mixture of:
1. Deionized water
2. Electrolyte such as Na2SO4 (0.1M)
3. A thickening agent such as xanthan gum (0.1-0.5%) to make a syrup-like consistency
4. A temperature based gelling agent such as agar (1%) to make the mixture gel when the temperature drops.

Mix a small portion of this mixture with activated carbon particles in the 25-100um size range. Keep mixing and adding liquid until the electrical breakdown voltage and capacitance of the mixture reaches it's peak.

Pour into a chilled mold causing solidification before the particles have a chance to settle.

Attach electrodes to the resulting block (using graphene paint to promote conductivity) and you have your capacitor.

---

If the average particle size is 50um, the average gap between particles is 50um, and 95% of the particles are not touching other particles, you can expect that electricity will pass through about 95 plates for every 1cm of thickness. Therefore if you consider 1v to be your cell voltage limit, you should have a 95v capacitor from 1cm of this material.

The way to measure breakdown voltage of the mixture is using a probe with 2 plates held 1cm apart and connected to a volt meter and a 200v DC power supply. You briefly connect the power supply sending 200v to the plates which is almost certainly too much for the capacitor and will begin making hydrogen, then you disconnect the power supply and watch the voltage fall until it stabilizes (you have charged this small part of the capacitor).

The major challenge is what's known as percolation. You want as high a percentage of carbon as possible, but too high and it will just bridge conductive paths through the water and kill the cell. Larger carbon particle sizes, and the addition of thickeners such as the xanthan will increase the percolation threshold. I think a good but realistic goal is 50% carbon by volume, but that's including the internal pore structures of the carbon as as "carbon volume".

Estimating the capacitance without building one is a challenge. Amateur Youtubers have had little trouble reaching energy density that is on par with commercial supercaps. One might imagine that with 50% carbon, this design would achieve 50% of the storage because the "plates" are only half dense. But on the other hand, this design also removes 90% of the metal, so it might come out a wash.

You could even remove more metal, by making a 10cm wide capacitor running at 1,000 volts. You could even eliminate more metal by using a rod down the center of a 20cm diameter tube. If you're okay with 10,000 volts then your tube (tank) is 2 meters in diameter. 10,000 volts is of course challenging to work with, but it is possible. Automotive and oil furnace ignition systems operate in this range, it's high but it's not "spooky tesla coil power" range. Conveniently, a 2 meter wide tank is about the maximum size you want to deal with, even for stationary power storage, so everything arrives at it's limit at the same time.

But what will this store? A 3000F commercial supercap is about 1/2 liter of volume and stores 7 watt-hours. You need 143 of those to store 1kWh of energy, which means about 71 liters. So with our 1000v in a 20cm wide tube, we would be looking at 2.26 meters of height.

So like 8 inch 7.5 foot tall tube storing 1kWh and replacing a 70€ battery. In the 10,000v 2 meter example, 2.26 meters of height would get you 100kWh of storage, the equivalent of 7,000€ worth of batteries.

So while the weight and volume is huge compared to lithium ion, the cost feels like it's right on the precious of being economical for stationary power storage.

Hihi! Lety here, auto-commenting from my main account (which doesn't have a 🔕 icon)!

This is how my PeerTube videos look on other Fediverse platforms!

Remotely interact with this video using an account on an ActivityPub-powered platform like Mastodon Social! Just click the “Add comment...” box under any PeerTube video and enter your Fedi handle in the pop-up. That’ll direct you to the federated post for that video on whatever platform you use.

Or, if you’re already logged in on Mastodon or wherever you're seeing this message, just look at the post I’m responding to!

Replies and favorites on that post show up as comments and likes on PeerTube, and following the account that posted it subscribes you to my videos.

Heads up, though! While some platforms might allow you to respond with custom emojis, gifs, images, polls, and reactions, most of that fancy stuff won’t show up correctly on PeerTube. The same goes for any edits you might want to make to your response unless you delete & re-draft.

If you already know all this or are tired of seeing this wall of text, you can hide these explanation posts by going to your account preferences and creating a new filter with the title and keyword “#LetyDoesPeerTubeExplainer” and all context boxes checked.

Thanks so much for watching! ⚡​⚡​⚡​

Hihi! Lety here, auto-commenting from my main account (which doesn't have a 🔕 icon)!

This is how my PeerTube videos look on other Fediverse platforms!

Remotely interact with this video using an account on an ActivityPub-powered platform like Mastodon Social! Just click the “Add comment...” box under any PeerTube video and enter your Fedi handle in the pop-up. That’ll direct you to the federated post for that video on whatever platform you use.

Or, if you’re already logged in on Mastodon or wherever you're seeing this message, just look at the post I’m responding to!

Replies and favorites on that post show up as comments and likes on PeerTube, and following the account that posted it subscribes you to my videos.

Heads up, though! While some platforms might allow you to respond with custom emojis, gifs, images, polls, and reactions, most of that fancy stuff won’t show up correctly on PeerTube. The same goes for any edits you might want to make to your response unless you delete & re-draft.

If you already know all this or are tired of seeing this wall of text, you can hide these explanation posts by going to your account preferences and creating a new filter with the title and keyword “#LetyDoesPeerTubeExplainer” and all context boxes checked.

Thanks so much for watching! ⚡​⚡​⚡​