So i get the electrolyte, but how does this polarize?
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MIT engineers create an energy-storing supercapacitor from ancient materials
41–50 of 101 posts
Re: MIT engineers create an energy-storing supercapacitor from ancient materials
#42Re: MIT engineers create an energy-storing supercapacitor from ancient materials
#43Earlier quoted context omitted.
To estimate the cost and practicality, assume you build a tower 120 meters tall and machinery able to lift 60 tons block of concrete to the top, then retrieve the stored energy by lowering it to the ground level. Think for a moment how much that would cost. Then calculate: mgh = 60000kg x 120m x 10m/s^2 (assume acceleration of gravity is 10m/s^2 for simplicity, no energy losses due to friction etc). The result is 72…
>assume you build a tower 120 meters I think the more popular approach is to use a deep hole, like a mine shaft. Maybe depth measured in kms. Because you're suspending from above you might be able to get a bit heavier than 60 tons.
useage in this manner could lead to a mineshaft gap
Re: MIT engineers create an energy-storing supercapacitor from ancient materials
#44Typical university press release: this technology can revolutionize our energy grid by storing energy in a building’s foundation, because we powered an LED with some tiny cells we made.
Yeah, let's go ahead and store huge electrical charges in the foundations of every new house built! What could possibly go wrong?
Re: MIT engineers create an energy-storing supercapacitor from ancient materials
#45Earlier quoted context omitted.
This may be true, but if it's going to be used for housing foundations regardless (because there aren't competitive alternatives), then it's essentially a sunk cost. The fact that you can get a supercapacitor out of your foundation for very low incremental cost is amazing (assuming they can scale the technology as anticipated). One thing I wondered about is what happens as the concrete expands/contracts due to weathe…
Surely a fractured supercapacitor is basically a bomb waiting to explode?
Depends on if it can short its charge to ground I guess, and how fast. An uncharged concrete capacitor is of course pretty harmless even if it cracks, so perhaps you could pour some strain gauges into it so you get advance warning of impending problems.
Re: MIT engineers create an energy-storing supercapacitor from ancient materials
#46Typical university press release: this technology can revolutionize our energy grid by storing energy in a building’s foundation, because we powered an LED with some tiny cells we made.
Yeah, let's go ahead and store huge electrical charges in the foundations of every new house built! What could possibly go wrong?
The floor is l̶a̶v̶a̶ lightning.
Re: MIT engineers create an energy-storing supercapacitor from ancient materials
#47Earlier quoted context omitted.
To estimate the cost and practicality, assume you build a tower 120 meters tall and machinery able to lift 60 tons block of concrete to the top, then retrieve the stored energy by lowering it to the ground level. Think for a moment how much that would cost. Then calculate: mgh = 60000kg x 120m x 10m/s^2 (assume acceleration of gravity is 10m/s^2 for simplicity, no energy losses due to friction etc). The result is 72…
>assume you build a tower 120 meters I think the more popular approach is to use a deep hole, like a mine shaft. Maybe depth measured in kms. Because you're suspending from above you might be able to get a bit heavier than 60 tons.
A kilometer deep hole is not very cheap.
Re: MIT engineers create an energy-storing supercapacitor from ancient materials
#48Seems to me that the potential of simply lifting a weight up (storage) and down (generation) beats these fancy engineering goals for cost and practicality. Especially if the weight being lifted is a container full of rocks. At first glance there are plenty of those everywhere. No hills or reservoirs needed either. Of course, no papers need to be published ... that may be the goal.
I’m excited about gravity storage but everything I’ve read indicates that the density and scalability are just not quite feasible.
Building the contraption that carries weights is not feasible. Worse yet, if you have to pay for the weights, then your idea needs to be thrown out entirely because you will never recoup the cost of a manufactured weight.
Re: MIT engineers create an energy-storing supercapacitor from ancient materials
#49Earlier quoted context omitted.
Unpopular opinion, most of MIT's research claims are preposterous and can be safely ignored. Their undergraduate education is quite good, but the research output is quite shoddy. The only exception is their computational photography group (Fredo Durand) is pretty legit.
No their research is much better than most. In my field of Robotics, Russ Tedrake, Alberto Rodriguez regularly get out impactful work (and I have a disdain for most work especially the kind Google does). I think they kind of lost out in Deep Learning to Berkeley and Stanford but they’re slowly building their expertise in it (frankly most of Academia doesn’t compare to industry outputs in Deep Learning so I don’t thin…
I agree that Russ Tedrake is great, I've watched his online lectures on underactuated robotics.
Re: MIT engineers create an energy-storing supercapacitor from ancient materials
#50There is usualy steel reinforcement (rebar) in the concrete. Isn't introducing electrical current gonna cause galvanic corrosion of the rebar? Might even affect concrete structures around the capacitor, not just the capacitor itself.
Also if i understood correctly, this capacitor would need to be kept wet (with water) to remain operational right? Wet basement is extremely annoying thing with many unpleasant consequences to say the least. So this might require some efforts to maintain the moisture while keeping it contained.
How do you replace this thing? Eg. once cracks inevitably form in concrete, or when the carbon structure get damaged by accidental overvoltage/overcurrent, or when the insulation layers deteriorate. You cannot simply replace foundation of a building. Therefore it would make sense to keep the capacitor at least partialy separated from the structural parts of the building.
Anyway this seems as an interresting idea and i wonder if plastic bucket full of concrete would be enough to power something like UPS to provide 100W to keep PC running for 15 minutes. Might as well stop replacing lead acid batteries every other year if this is at least remotely viable.