Supercapacitor-On-a-Chip Now One Step Closer (ieee.org) 53
schwit1 writes: In 2010 Spectrum reported a new approach for creating chip-scale supercapacitors on silicon wafers, proposed by researchers at Drexel University in Philadelphia and the Universite Paul Sabatier in Toulouse, France. In an article published in Science, the researchers described how to make supercapacitor electrodes from porous carbon that could stick to the surface of silicon wafers so that they could be micromachined into electrodes for on-chip supercapacitors. Now the same team has finally succeeded in doing just that.
In a paper published in this week's Science, researchers from the two initial teams report creating efficient porous carbon electrodes that really stick to the surface of a silicon wafer. They made layers of porous carbide derived carbon (CDC) that are completely compatible with all treatments used in the semiconductor industry, says Patrice Simon, a researcher at Universite Paul Sabatier who has researched porous CDC electrodes over the last ten years and co-authored both the 2010 and this week's paper in Science.
And? (Score:2)
Is it too much to ask for a "And why this is a big deal" in the summary, or do I have to turn in my nerd card?
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1 .Do you know what a chip is?
2. Do you know what a supercapacitor is?
3. Do you know where your towel is?
Re:And? (Score:4, Interesting)
I'm not clear on this either. Why would someone want to build a large-area device, like a super-capacitor, on top of an IC? given that the cost per unit surface area of a modern IC is astronomical?
The question is particularly complex, as we are talking about super-capacitors. Super-capacitors usually have terrible AC characteristics. If we were talking about high-performance ceramic capacitors, then the answer would be to improve the AC performance of the power distribution net, or for RF communications.
Alternatively, the answer could be to power a portable device. However, a typical capacitor has such a large surface area that it is a roll (or a stack) of many layers. To power the portable device, the surface area of the chip would have to be very large relative to its power consumption. This would be an unusual combination, as power consumption is often a function of die surface-area.
In concept, any device will have an application. However, I'm not clear on what the application for this device would be ...
Higher capacitance per unit area (Score:5, Informative)
I'm not clear on this either. Why would someone want to build a large-area device, like a super-capacitor, on top of an IC? given that the cost per unit surface area of a modern IC is astronomical?
Because a supercapacitor is not defined by being a large area. A supercapacitor can be any area.
Its defining characteristic is a higher capacitance per unit area than conventional capacitors. So, a supercapacitor is actually smaller area than the same capacitance in a conventional cap.
The question is particularly complex, as we are talking about super-capacitors. Super-capacitors usually have terrible AC characteristics.
Some, but not all, applications of capacitors require good AC characteristics.
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I can't think of an on-die application that would not need _really_ good AC characteristics to be worthwhile. You're adding [super]capacitance there as the lowest ESR/ESL charge reserve you can make. If you can't beat an MLCC on top of the leadframe, you're adding expense to be 'cool', but not adding performance.
Re:And? (Score:5, Interesting)
I can think of several good reasons. Decoupling the "droops" on the local power lines from local circuits drawing or providing excess current for signal lizes comes to mind immediately. It's easy to put in a large local capacitor to decouple many devices, but harder to find the board space to put a small, high frequency capable capacitor _right next to_ the power leads that connect each chip to the power bus or to the power plane.
I've seen a number of complex board designs ruined when a new engineer, or a middle manager, insisted on replacing a set of small capacitors with one large one. I've even myself had to wire in small capacitors, manually, on top of soldered in chips to provide the necessary decoupling. I'll also admit that that was decades ago: I don't have the eyes and hands for that kind of work anymore.
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Decoupling the "droops" on the local power lines from local circuits drawing or providing excess current for signal lizes comes to mind immediately. It's easy to put in a large local capacitor to decouple many devices, but harder to find the board space to put a small, high frequency capable capacitor _right next to_ the power leads that connect each chip to the power bus or to the power plane.
To my knowledge it is even worse. You need to decouple the power grid of the individual parts of the IC against each other as well as the power supply (often also on chip for microcontrollers). From what I learned in a previous job most of the empty space(*) on current microcontroller dies is converted into capacitance to buffer the effects of power draw by switching transistors. And discussions sounded as if that was already becoming a limiting factor, so more capacitance (by attaching super capacitors on
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I think you're confused, but perhaps because I didn't go into enough detail for people who've not looked closely at it. We're also looking back into physics and electronics training required long ago in my career, when learning computers involved building them from bare components and involved learning the limitations of transistors themselves.
A typical digital circuit is tied to ground and power, and tied to input and output circuitry. When current is drawn from ground, and power, to change output signal s
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https://en.wikipedia.org/wiki/... [wikipedia.org]
Supercapacitors are used in applications requiring many rapid charge/discharge cycles rather than long term compact energy storage: within cars, buses, trains, cranes and elevators, where they are used for regenerative braking, short-term energy storage or burst-mode power delivery. Smaller units are used as memory backup for static random-access memory (SRAM).
If you start designed computers as self-contained modular blocks, you would want the CPU and memory together with so
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With the Dremel 3D printer available at Home Depot, it means 3D printing isn't hype anymore.
No, the missing phrase is... (Score:1)
No, the missing flamebait phrase is "percentage of women doing X is woeful". (e.g., http://tech.slashdot.org/story... [slashdot.org])
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Is it too much to ask for a "And why this is a big deal" in the summary, or do I have to turn in my nerd card?
Very few things are a big deal at all. Look through the last year of Slashdot articles. I doubt you will find much that actually had an immediate and significant impact on your life.
What the summary implies is that the supercapacitors could be integrated on the same wafer as other components.
If this is true then it could lead to a bunch of interesting component improvements.
The thing here isn't that you suddenly can create consumer applications that weren't possible before, but rather that they can be made
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Re:And? (Score:5, Informative)
This article Is about installing super capacitors on the board replacing regular capacitors. Not about replacing the battery
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Basically, a supercapacitor on a chip could be the next generation "battery" everyone is seeking for mobile phones etc.
If this were true, manufacturers would be using existing discrete supercapacitors in phones; but they aren't, are they?
Integrating components on chip merely drives your costs down; it does not bring added functionality.
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Basically, a supercapacitor on a chip could be the next generation "battery" everyone is seeking for mobile phones etc.
If this were true, manufacturers would be using existing discrete supercapacitors in phones; but they aren't, are they?
Any existing supercap which stores enough energy to power a phone for a day or more is much too bulky to fit inside a phone, so miniaturising supercaps would bring new applications.
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What would make you think that miniaturizing supercapacitors would in any way improve their energy density?
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What would make you think that miniaturizing supercapacitors would in any way improve their energy density?
My understanding is that decreasing size and increasing energy density are linked because creating better ways to build better nanostructures underpins both aspects.
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they could store enough charge to run the phone for days or even weeks.
Not true. Even the best supercaps have an energy density far lower than batteries.
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they could store enough charge to run the phone for days or even weeks.
Not true. Even the best supercaps have an energy density far lower than batteries.
Not true right now, but the article is all about miniaturising supercaps. Miniaturising supercaps to chip-scale could, in theory, massively increase the energy density such that it exceeds that of Lithium batteries. That still looks like it's a long way off though.
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the article is all about miniaturising supercaps.
No it isn't. It is about making them stick to silicon.
Miniaturising supercaps to chip-scale could, in theory, massively increase the energy density
No. Energy density is an intrinsic property. It doesn't change with scale.
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Doesn't matter when the recharge time is a matter of a couple of minutes instead of hours!
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Smaller? Obviously. Denser? Not obvious AT ALL.
Re:And? (Score:5, Informative)
Utter and complete bullshit. No supercapacitor comes anywhere near the volumetric energy density of even a fair to middling battery.
You could have found this out in about 5 seconds [wikipedia.org], even if you are too ignorant to already know it.
Supercapacitor: 0.06-0.05 MJ/l
Lead acid battery: 0.56 MJ/l
Lithium-ion battery: 0.9–2.63 MJ/l
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Re: And? (Score:1)
Thanks for link I didn't realise with all innovation that lithium is still only 5 times better than poor old lead acid by weight
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By *volume*. By weight is going to be much, much worse.
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Off the top of my head it would allow watch battery type applications. Where as small batteries are either disposable or rechargeable but with limited lifetime and very slow recharge times (hours), these would have very long lifetimes and be rechargeable in a matter of seconds.
These supercapacitors (Score:2)
One step closer? (Score:1)
Not very meaningful without a context. If it has taken them years to take this step, and they are still one hundred steps from mass deployment, there are not many reasons to feel all that excited about it.
too many links (Score:3)
there are too many links in the summary to bullshit that doesn't matter. seven links is to many. keep it down to one or two.
If I had to guess why this is a good thing... (Score:5, Interesting)
At first thought, putting capacitors on the chip means that EVERYTHING for an application could be put on a piece of silicon and not require any interconnections. This could be very valuable for (very) high frequency RFID tags where the chip contains the logic, radio, antenna and power supply good for a few milliseconds of operation without any external components. This could easily halve (or more) the cost of an RFID tag and reduce it to just dropping a chip into the tag's (or even product's) plastic mold - it's been a number of years since I saw the state of the at on RFID tags, but they were to cost $0.15 to $0.25 each in quantity. Without any external parts, this cost could drop to a few pennies.
The other application I can think of are chips which need a defined power down sequence or else be damaged/lose data. The obvious example for this would be in a Flash chip with a write buffer - if power was lost, the contents of the write buffer would be saved to non-volatile storage before it was lost.
Others? I think the RFID tag is probably the application where this technology would be most valuable.
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I had a weird dream the other day involving a high-temperature superconducting film of carbon nanotubes with a tungsten atom inside. The film was woven back and forth on a nanoscopic level, sort of in that compressed zig zag manner like corrugate; that, taken as a linear unit, was then drawn in a trace inductor scheme (a spiral of wire), making a trace of superconducting air-gapped tungsten impregnated carbon nanotubes.
Apparently my brain was trying to work out implanting a microscopic nano-super-indacit [youtube.com]
Seems counter-intuitive on many levels. (Score:1)
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There's an application for this then: tamper-proof chips.