I realized my explanation of how these work was vague and poorly worded, sorry! Graphene-based supercaps are a form of electrostatic double-layer capacitors (EDLCs). Charge is stored at the interface between the electrode and electrolyte via electrostatic attraction when charged. Due to the small charge separation EDLCs can charge and discharge very quickly, and the extreme surface area of graphene foam gives a large interface with the electrolyte to improve overall capacitance. That's why the "perimeter" of interdigitated electrodes is important, because more exposed perimeter == more interface opposing the other electrode to accumulate charge.
What goes into selection of optimal electrolyte? What gives kapton tape this property of UV -> graphene? Could you estimate your capacitance economy? Like capacitance per area, volume, dollar, time, etc?
One other point on you're value measurements... It is not uncommon for capacitors to be manufactured under "tolerance" of 20% or more, so the meter might not be as inaccurate as it looks.
Your capacitance meter is likely more accurate than you realize; most commercial capacitors have a fairly wide tolerance from their stated value. Manufacturers data sheets should list the tolerance for each type the produce.
Agreed. One of the caps he tested looked like it was rather old (the 5uF unit). First, if it actually was rated 5uF, it really is old, because anything made after say, 1975 would likely have been a 4.7uF, not a 5uF unit. Anyway, old electrolytic caps tend to become leaky, and leaky caps often read high on capacitance checkers, even though their true capacitance is falling.
@@Gwallacec2 btw a quantum leap is extremely small. I mean I guess from the perspective of virtual particles it's extremely large, but a quantum leap is like between electron bands Then again scale becomes a very strange thing to consider eventually so I'll stop there.
It would be amazing to see RU-vidrs start a license free movement, I was just watching one guy create spider silk using genetically modified yeast and released the gene sequences he developed under an MIT license. Absolutely amazing, his next step was to actually have the yeast absorb graphine and/or carbon nanotubes to bond them in the silk to make it stronger.
I agree! It's pretty amazing what some of the minds on YT are capable of :) IIRC that was Thought Emporium.... he does some really fantastic work. One of my goals is to help spread knowledge of these interesting papers that are just buried in archives. Would be neat to see what we could accomplish as a group on YT sharing and developing different techniques that would normally end up in a paper or patent.. There are other interesting developments too, like Joe Barnard (BPS.space) working on launching suborbital rockets, etc. I'm happy to see YT being more than _just_ entertainment.
Your point about reaching a level of technology in a society where we can do pretty serious testing and innovation in our garages with off-the-shelf components is spot on… This is the future I ordered! Liked and subscribed! 😎👍🏼
every school need to have machine shops and maker spaces and every community needs to have at least one guild hall of sorts where crafts men and women can ply there craft and find young apprentices to share there knowledge with.
Welp, this is one of those treats of RU-vid: An easy insta-subscribe with a new underappreciated channel. I look forward to watching your channel eclipse 100k subscribers in the next 6 months.
Really good presentation on this... you talk so naturally with no hint of "I'm reading a script" and no "uuum" or "aah" either. Nice smooth editing too.
This capacitor seems like it could be useful as the flexure part of a homemade MEMS scale strain gauge, pressure or temperature sensor. Guys like me who are only hobbyists can't afford off the shelf devices just for the hell of it so making them is the only way to go. Lol
The reason for the high values could also be leakage current. Especially on cheap meters, leaky caps can lead to much higher readings than the actual capacitance.
The bed heaters on my 3D printers typically have kapton covering them. They also suffer from being inconsistent and take a long time to come up to temperature with DC power (less so with the AC bed heaters), with less heat near the outer edges. If the kapton covering them were the actual heat source then I imagine it would perform MUCH better. :)
I immediately thought about the same thing. Aluminum is often used to spread the heat from the wires of a heater. Lot of the heat is lost to the backside of the plate. So what if you had a glass bed, completely covered with kapton tape and a standard PEI sticker on top of that. Glass is more rigid than aluminium, has lower density, is a fairly poor conductor of heat and even cheap glass sheets are usually flatter than aluminum. So one can have a lighter, more rigid and flatter bed, reduce losses from the backside and get a more uniform heating. Manufacturing this should be very easy too. Just apply kapton tape to the glass, treat it with a laser, run two pieces of copper foil on the sides for power, then apply PEI sticker on top. Or, perhaps a magnetic sticker to enable the use of removable flex sheets.
@@anttiandreimann8456 you'd also have to figure out where to shove the sensor to feed data back to the controller, and hope your PID tuning algorithm works properly. That said, insulation layer, kapton, electrodes and thermistor, then print bed should work really well and keep the heat directed upwards.
@@anttiandreimann8456 You could make the bed heater using the printer itself. Just mount the laser to the print head and run it uniformly over the kapton.
@@AlexanderTzalumen to try it out crudely there's a simpler solution, since the resistance of the "heating mat" shouldn't vary too much with the temperature swings (at max up to ~100°C of swing from ambient, for general 3D printing with "normal" materials) you could even characterize it measuring the temperature with a thermocouple vs PWM percentage of current, and then control it just by using a look up table and not even need a PID controller, as a certain amount of PWM controlled current should provide the same temperature consistently. Although thermal imaging would be necessary to ensure the current is not traveling in just a straight line or area of the mat (think skin-effect) as opposed to through the whole mat, because PWM-ing creates a lot of high frequency harmonics which may (or may not) induce this effect. Might give this a try one day if I get myself a laser, hope someone beats me to it because it sounds promising IMHO
@@markopesevski perhaps, but the marlin firmware used in the majority of hobbiest and consumer 3d printers all use PID controllers for their heating elements, partially for the initial temperature ramp, and also for maintaining temp stability against the various sources of heat loss (radiant losses, ambient air currents, part cooling fans, moving build plate, etc). For a heated build plate, inconsistant temperature can lead to 1st layer delamination, which will cause the print to shift, warp, or fully detach.
Great research and presentation! The applications for this technique are huge! I'm an electronics engineer. And I think there's a possible fault on the capacitance metering. Multimeters presume you are measuring a capacitor, but electrodes in a acid medium will make a resistor(or RCL equivalent circuit), also may be electro-chemical reactions going on. There is no insulation on your device and electrons are flowing between terminals. It will probably self discharge almost instantly. To measure a capacitor precisely you first need to charge it, disconnect from source, than connect it to a load. Integrate the power it produced and you will have the energy it is able to store.
Ah interesting, does that apply when using a dedicated "capacitance meter"? I had assumed/hoped it had internal circuitry to power the cap to some degree and test it's leakage or something? This is the device I have: www.newark.com/general-tools/cap1500/capacitance-meter-digital-200pf/dp/59P4162 I did find that it self-discharged very quickly just sitting on the bench, and made even worse when poking it with a multimeter :) I'll see about setting up some kind of circuit as you suggest to test it. Thanks for the help! Electronics is definitely not my forte, very much a newbie still :)
@@BreakingTaps Hard to tell what process it uses to measure. But I think you don't have a capacitor(yet). You need an insulating medium between electrodes. For example electrolytic capacitors use aluminum oxide. In a capacitor electrons can't flow between terminals, there should be an insulation, where an electric field will be created to store enery.
@Eduardo Schoenknecht So big grain of salt due to my general ignorance, but my understanding from the literature is that these types of supercaps operate a bit differently. When charged, a helmholtz double layer is formed symmetrically on the electrodes using the ions in the electrolyte (graphene + | - electrolyte + | - graphene), so there isn't actually a dielectric in play here. Just ions associating / disassociating with the graphene at the interface between liquid and solid. In theory, based on my reading, but as I said I could have that incorrect :)
@@BreakingTaps you are right. And I don't have knowledge on super capacitors chemistry. But I think a special electrolyte is needed, regular diluted sulfuric acid will just conduct electricity.
Roger, thanks for the help! Will do some more reading on my end. I'm itching to see if I can scale this thing up, so might be able to make a more robust v2 at the same time :)
Just waiting for the youtube algorithm to bless this channel. Great work as usual, I'm using your metallic microlattice video for one of my projects right now.
@@BreakingTaps Played around with this graphene concept last weekend, turns out it works really great with the 10um co2 lasers, which is mighty convenient. Also turned much more black (vantablack?) than yours. Anyways, do you have a discord server or something? It would be neat to hang around, as I and a few friends are all doing similar stuff as you
@Wid Lay Awesome, glad to hear it! The first LIG papers were done on CO2 iirc, and there are some neat followup papers where they perform multiple passes to turn amorphous carbon into LIG (which isn't possible with shorter wavelengths like mine). Was used to make supercaps on coconuts and potatos as demonstrations :) I wonder if that's why yours was blacker? The literature shows that LIG is a big mess of graphene + amorphous carbon + fullerenes + tubes, so I wonder if the CO2 does a better job of converting some of the non-graphene into graphene? Dunno, but interesting result! No discord at the moment, but I was just thinking it'd be fun to have a place to gather folks working on similar stuff. Lemme set one up and I'll give you a ping!
I wanna go to the kind of party where people demonstrate shit like this to each other. Party tricks where I'm from are usually something like someone opening a beer bottle with their eyebrow.
I actually have a friendly competition where my friends and I compete to create the coolest mechanical thing based on a theme. At the end of every other month we get together and show it off. You should join us! 😂
I've seen this editing style on quite a few channels lately. I'm guessing there is some popular videography instructional video out there that was promoting it.
@@BreakingTaps second camera is a nice touch, you could always just turn towards it, would be nice if you wanna add some extra info or something, like an aside in theatre....or malcolm in the middle haha
or the tangent cam, for when you go to explain something that is a bit off topic or complementary, but please do keep looking at us. tv show style makes me want to switch channels...
This channel is one of my favorites actually, really awesome content. And that laser induced graphene are so versatile that a lot of technological applications can be made with that. Thanks to show us that amazing technique.
capacitance reading may be off in this case due to high leakage resistances, you need some type of rlc meter to determine simultaneously Parallel, series resistances AND capacitance. Parallel Resistance is responsible for leakage currents -determines self discharge speed actually, while series resistance is like a series connected resistor - limits the current and has other detrimental effects. But anyways with some clever experimentation I think you can figure out all of them. nice job.
So great to see the recognition starting to happen for this channel - I keep trying to pump the views a little (I just love rewatching lasers blow polyimide into carbon foam). I'm trying a repeat on this but using a second copper deposit layer for charge collector.
Aw man these just keep getting better! Your production quality really shows, I can't imagine how much time must go into each of these shots. Keep up the great work! (Not to mention the great science you keep showcasing, I really like this series where you recreate scientific paper results)
That does it. I'm building my Pi/Arduino laser CNC. I just found this post and it seems like it exactly matches my interests. Manufacturing, electronics, programming and materials.
Incredibly impressive project! Now I want to go order a laser from my printer and make use of the big roll of Kapton I've got. =] Great quality of shots, editing, and sound too. You put out a high quality video sir!
One important test for your capacitance meter -- put a resistor across it, no capacitance. Does it still try to produce a reading? If so, you need to be cautious about taking the measurements too seriously. Try also measuring DC resistance of the assembled graphene devices. WIth capacitance, the reading will start low and climb, but see if it tops out at some level or rises to effectively infinity (== good capacitor!)
Bruh, this was an awesome explanation, I got most of what was explained. So facinating you made this with advanced homemade tools. I learned something today just as I got bored real happy about that.
Now we can put the mask on it and deposit copper on some regions to get a good conductors where we need it. Feels like a good method for making thin and flexible electronics.
Great project! I'd be interested to see the leakage current and how long the capacitors will hold voltage with no external connections. Leakage current could also influence the readings from your multimeter, so this is something to watch out for.
Forgive the newbie question: I should be able to test this with just an oscilloscope right? Charge up, measure the discharge for a given period of time and then work out the resistance / leakage current from that?
A crude but portable way to check capacitor condition is to put a multimeter across the terminals and see what the resistance stabilises to. Ideally it should be infinite, but you know a motor start capacitor has definitely failed when it has a resistance under a few hundred ohms :). My understanding of the way most multimeters measure capacitance is they time how long it takes for the capacitance to reach a certain voltage from 0v with a known constant current, so any leakage resistance decreases the amount of current charging the capacitor and makes it appear larger in value than it actually is. I have also used an LC meter that seems to use some form of oscillation to measure capacitance and this seems a bit less sensitive, but can still do weird things with high leakage currents.
It would be very interesting to see the conductivity of the grapheme. Essentially you measure with a multimeter a square sample of the material with the entire edge of the two measurements points as electrodes. Or, alternatively, you measure both voltage and current of the heater version and use ohms law, then divide by the length to width ratio. This is quite important for any design optimization.
The heater peaked my interests. Living up north and especially with the weather getting more extreme, the snow and freezing rain can really be a problem for us. You've given me some ideas on how to implement a cheap diy heating system for driveways and sidewalks etc. I'd be interested in seeing you expand on the low voltage high temp heater in the use cases I've mentioned above but none the less great video!
There has been a _ton_ of interestin that aspect, especially since it was more a footnote than anything. I think I'll probably do a followup video to see how it works in practice, would be interesting to see if there are limits on size, surface area, voltage/current, etc. Biggest problem is making good electrical contact but I have a few ideas. Cheers! (I'm also up in the frozen north so feel ya there :) )
From an electronics engineer: believe your meter, *not* the markings on an electrolytic cap. Electrolytics are literally formed by leakage current as long as voltage is applied. In storage, the oxide layer dissolves, causing the capacitance and leakage to rise and the voltage tolerance to fall If a device is left uncharged for more than a few years, it will often blow up from leakage induced heat when finally powered up again. The actual capacitance can easily be several time more than the markings but the voltage tolerance is a small percentage of design. Old caps can be reformed if put on a bench power supply for about a week with the current limited to a few milliamps and the voltage set to nominal (what the markings say). Meters are calibrated at the factory and even cheap ones drift very little. All my handheld Flukes stayed within 1% more than 10 years old, when I checked them against components measured on Lockheeds scientific instruments.
If you can reliably control the temperature, using the tape as a heater would be a great wrap for lithium batteries in cold weather climates. Have a temperature sensor turn on the heating tape when conditions are too cold to charge the batteries in order to warm them. Cheap, thin and flexible solution.
Electrolytic capacitors have a typical range of +80%/-20% although there are some better ones. This isn't usually a problem because in their use case more is often better and +80% means it can age quite a bit before it will become a problem.
So imagine PCB’s that hit up the circuit for applications in deep space and freezers. Today we use RTG’s to keep our circuits in space warm. Of course it also uses a lot more power.
I don't know if someone already mentioned this, but you can validate the capacitance assembling an LC oscillator using an inductor with known inductance and measuring the resulting frequency
Since most super capacitor designs are for energy storage with a DC voltage, it would be better to measure the capacitance under said operating DC bias. Measure the step response time of a discharge under constant resistance (eg. time the discharge from 3.0V down to 0.3V with 1000 Ohms across it).
Awesome stuff. I had to pause the video half-way through to go and try kapton tape on my own laser cutter... Yep.. works like a charm. Fantastic. I can see that I'm going to have some fun with this. Cheers!!
Imagine incorporating this material into clothing fabric. You could have a really effective means of generating direct, uniform heat over one's entire body, or selectively, based on the specific need of a separate body part. It could be used for operating in cold-weather environments, perhaps incorporated into the innermost layer of one's cold-weather gear. Likewise, it could be incorporated into a wetsuit, for cold-/deep-water diving. Perhaps most impressive, it could be incorporated into the spacesuits of the future, as a space- and energy-efficient means of maintaining body temperature in a scenario when space AND energy are at a premium. I wouldn't be surprised to learn it's already being developed for such use, or even that it's already being incorporated in this way.
"I'm not an electronics person" - my friend you're making a capacitor from scratch, and you understand its function. If that isn't an electronics person, I'm not sure what is.
What are these kinds of supercapacitors useful for? I remember being told, about 20 years ago, that super capacitors are ALMOST useful for storing energy, say for a car or a laptop. They can charge quickly and hold a lot of energy. The problem is that if you break one when it's charged you have a bomb. They also leak energy. But the bomb problem is one that batteries have as well, which is why super high capacity batteries are always promised but never happen.
I understand that this is a little late, but maybe this would interest someone. If you are aware of the inkjet transparency film; it has a emulsion layer coated on one side of an acetate sheet. That layer can be lifted off the acetate if you soak it in a lye solution. IF one were able to somehow transfer that very fragile emulsion onto the lasered polyamide it could be used as an electrolyte carrier. The emulsion may need to be neutralized of the basic lye solution, rinsed, and dried. It is very fragile when its unwashed and dried that may change when its not extremely basic. But it seems like it would have the properties needed since it is designed to be a carrier of water based ink solutions.
This caught my interest. I think you're on to something. What do you think would be the main benefits over other electrolyte carriers? Can you also explain why being a carrier for water based ink is related?
That heater at the end... if i had the project for it, I'd want to make a PCB reflow bed out of it. I'd love to see some power efficiency numbers just out of curiosity too.
for the heater, one of those bladeless fans with a ring of heater tape around the air vent could be run at super low levels to make a warm airflow that would be good for drying rather than baking something with a space heater. also run the fan on low so your not blasting something with high wind speed like if you wanted to dry your gloves or paint but dont want to risk fire with a proper heater or create runs with a powerful fan. its not a long term solution but in a pinch it could be useful. maybe blow warmed air into a box as a mini drying booth...
Yeah probably, in which case who knows what this cheapo meter would read. This setup has barely any surface area and it's not really different from a printed metal pattern from what I can tell.
Wow that's really interesting, thanks for sharing the knowledge. You got one more subscriber. Your channel is totally underrated, I came here from a hackaday article; here's hoping for more coverage of your work!!
Two things I'm interested in from this video: 1. Can you make a flexible version of this kapton tape capacitor with Farad levels of storage? Thinking about having a quick charging battery that you could work into a wearable, this seems ideal, even if the "battery" wouldn't last more than an hour (in typical circumstances, who isn't able to get to a wall outlet or at least install a battery inside of an hour?). Home printing a battery I could wrap around my wrist or across my back for example with a reasonable enclosure for durability would be great. 2. The "heater" at the end seems like it would make for a pretty great handwarmer system at super low Voltages, because 285C is a little much for skin, but maintaining a consistent 20-30C across your hand in the winter would be very ideal.
It seems you could scale the capacitance up by controlling the roll of kapton on the X axis and controlling the laser only on the Y axis. Essentially, allowing you to make super capacitor tape on a roll. Cut it to length for specific values.
Hi! Thanks for the videos and for your unique contempt style! It's inspiring how due to the internet we can do crazily complicated things on our own. I truly hope to get to the moon via DIY one day to open a space motel and serve 3d printed chicken, ranch sauce and salad sandwiches to brave colonists and scrappers. Keep it up, hope the dopamine was delivered
