4 ms·
Apparently they are on par with energy density and power density. They are way ahead on cycle stability (30k charges). So that pretty much leaves two things: 1
by daveguy 10y ago
Apparently they are on par with energy density and power density. They are way ahead on cycle stability (30k charges). So that pretty much leaves two things:
1. Charge stability. Does it leak like a sieve even without a load after being charged?
2. Manufacturability. I expect this is the big problem. It's a chemical engineering problem to scale up a "nano" process. The article says it's not ready, but doesn't say what the biggest challenge is going forward.
Anyone know this particular supercapacity tech? Or supercaps in general?
- honkhonkpants 10y agoWell they are about an order of magnitude below state-of-the-art batteries in terms of energy density, and about the same distance above batteries in terms of power density. For phones this doesn't seem to make sense unless you want your iPhone to be 3cm thick. Maybe an application with greater power demands?
- john_reel 10y agoCan you explain the difference?
- honkhonkpants 10y agoEnergy density is the energy stored per unit volume or mass. Power density is the same thing, but per discharged per unit time. It is essentially a volumetric statement of the internal resistance of the battery or capacitor. Supercapacitors can be discharged very quickly compared to batteries of the same size, but the same sized battery contains more energy.
- bigger_cheese 10y ago>2. Manufacturability. I expect this is the big problem. It's a chemical engineering problem to scale up a "nano" process. The article says it's not ready, but doesn't say what the biggest challenge is going forward. Quoting from the article: "The team at UCF has experimented with applying newly discovered two-dimensional materials only a few atoms thick to supercapacitors. Other researchers have also tried formulations with graphene and other two-dimensional materials, but with limited success." I'm not sure if they used Graphene specifically (the only other 2D matl I know is silicine) but there are manufacturing issues involved with Graphene especially around mass production but these are being solved. Graphene used to be one of the most expensive materials in the world to produce (per unit weight). It is now (2015) "only" about $100/kg. compare this with something like thermal coal (another carbon based matl) at under $100/t. There is still orders of magnitude in the price before economics look good. edit: That is not to say it is worthless the price has fallen fast in last 5 years it just needs to keep at the same trajectory for a while longer. Graphene is after all an extremely new material. I don't think there is anything fundamentally impossible to solve manufacturing wise and economies of scale should kick in as demand for it increases.
- ant6n 10y agoI wonder whether super-capacitors could be fabbed. At the end of the day it's just two large surfaces.
- vanderZwan 10y agoThere's also a third problem, which is that capacitors typically don't have constant voltage. Unless there's something special about these capacitors that they're not mentioning in the articles.
- dragontamer 10y agoNor do batteries (although batteries are far flatter than capacitors). That problem of "sagging voltage" is solved with either a buck-boost converter, or a buck-boost inverting converter... or a SEPIC converter. Good ones get ~95% efficiency or so.
- cperciva 10y agoA leaky capacitor could still be useful in combination with a battery - you can dump power into the capacitor for a super-fast "charge", then slowly move the energy into the battery. You don't get the capacitor's cycle stability, but at least you get the charging speed.