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MIT engineers create an energy-storing supercapacitor from ancient materials

news.mit.edu

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Re: MIT engineers create an energy-storing supercapacitor from ancient materials

#71

Post by Twirrim »

robinzfc wrote: post #29
8bitsrule wrote: post #12

Seems 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.

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…

I love comments like the one above yours "just do this eyesore/expensive/impractical thing instead!"

Good enough is good enough. There is no one size fits all, and we really need to start leveraging everything we can to tackle energy storage. Each thing used doesn't need to be perfect for energy density, it just has to be good enough.

> assume you build a tower 120 meters tall.

vs sticking a concrete block in the ground like this paper is proposing.

As long as the durability is there, and it scales up like they say, this concrete block thing has interesting practical potential, because concrete is so ubiquitous. It's in foundations, it's in walls, it's in floors, it's under the road, sidewalk etc.

Heck, where I live we could turn our whole street in to one big battery to service the neighbourhood, while we couldn't possibly stick a whopping great big tower with concrete blocks in it, or a suitable size water tower.

Re: MIT engineers create an energy-storing supercapacitor from ancient materials

#72

Post by turnsout »

ipsum2 wrote: post #26
dmvdoug wrote: post #19

Earlier quoted context omitted.

I thought the same thing, so I went and looked at the paper, and unfortunately, the paper itself has some of these kind of speculative claims as well.

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.

I wonder how much of this is due to the fact that the Media Lab sells access to corporations? They need to make their research and patent portfolio seem utterly transformative to justify the hefty subscription fee.

Re: MIT engineers create an energy-storing supercapacitor from ancient materials

#73

Post by EthanHeilman »

ipsum2 wrote: post #26
dmvdoug wrote: post #19

Earlier quoted context omitted.

I thought the same thing, so I went and looked at the paper, and unfortunately, the paper itself has some of these kind of speculative claims as well.

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.

MIT doesn't have research claims, it has professors and graduate students who do research. As an elite institution that is hungry for research grant dollars, it attracts top researchers that often do excellent research but not always.

What human being would even be qualified to judge the research output of a large research university across all fields? A research university is an umbrella under which hundreds of independent teams perform research. You can do journal metrics, but those have a long latency, you are measuring performance 2 to 10 years in the past, and such metrics are not without bias.

Re: MIT engineers create an energy-storing supercapacitor from ancient materials

#74

Post by slow_typist »

For 2 m^3 of the material you will need around 1 metric ton of cement. You need around 2.8 GJ to produce 1 t of cement.

Therefore you need 63 GJ or 17500 kWh to produce a capacitor of 45 m^3 that can hold 10 kWh. (Omitting the 3% carbon in the mixture obv.) I hope the thing is really resistant and cycles forever without degradation.

BTW cement production contributes substantial amounts to global carbon emissions.

Re: MIT engineers create an energy-storing supercapacitor from ancient materials

#76

Post by jszymborski »

slow_typist wrote: post #74

For 2 m^3 of the material you will need around 1 metric ton of cement. You need around 2.8 GJ to produce 1 t of cement. Therefore you need 63 GJ or 17500 kWh to produce a capacitor of 45 m^3 that can hold 10 kWh. (Omitting the 3% carbon in the mixture obv.) I hope the thing is really resistant and cycles forever without degradation. BTW cement production contributes substantial amounts to global carbon emissions.

In fairness, I think the idea is that you would create this from concrete structures that would be built regardless and used in other ways. Adding extra capacity to the grid for "free" would good.

Of course, this is a press release and they usually consist entirely of breathless exaggerations and wilful omissions of limitations.

Re: MIT engineers create an energy-storing supercapacitor from ancient materials

#77

Post by KennyBlanken »

sashank_1509 wrote: post #35
ipsum2 wrote: post #26

Earlier 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…

> No their research is much better than most.

Yeah, so good they were extensively faking their research and demos for a "personal food computer"...and even selling the fucking things to unsuspecting schools. Literally snake oil scamming.

https://www.google.com/search?client=firefox-b-1-d&q=MIT+med...

Then there's your robotics team, backed by millions of dollars in free products and "consulting" (ie doing work for them) in sponsorship by defense contractors...beaten by a bunch of high school kids who raided a BoatUSA store and Home Depot to build an underwater robot with bilge pumps and a bunch of PVC pipe.

The most exciting thing to come out of MIT Media Lab in two decades is an alarm clock wrapped in carpet that rolls off your nightstand when it goes off.

MIT is a defense industry thinktank masquerading as a university.

Re: MIT engineers create an energy-storing supercapacitor from ancient materials

#78

Post by regularfry »

rob74 wrote: post #52
harvie wrote: post #51

Earlier quoted context omitted.

i guess the voltage would be rather low... but current capacity might be enough to melt your drill bit, if you decide to drill hole through both of the electrodes :-D

Ok, TIL that the high capacity of a supercap doesn't translate into a ginormous voltage (Wikipedia: "A supercapacitor [...] is a high-capacity capacitor, with a capacitance value much higher than other capacitors but with lower voltage limits"). Good to know...

Specifically in this case they were limited to less than 1.23V because that's when you start to get water breakdown in the electrolyte solution (if I've read it right).

Re: MIT engineers create an energy-storing supercapacitor from ancient materials

#79

Post by pengaru »

slow_typist wrote: post #74

For 2 m^3 of the material you will need around 1 metric ton of cement. You need around 2.8 GJ to produce 1 t of cement. Therefore you need 63 GJ or 17500 kWh to produce a capacitor of 45 m^3 that can hold 10 kWh. (Omitting the 3% carbon in the mixture obv.) I hope the thing is really resistant and cycles forever without degradation. BTW cement production contributes substantial amounts to global carbon emissions.

Is your math accounting for the volume the added water occupies? The paper describes using excess water for deliberately creating voids the electrolyte can access.

AIUI when mixing cement any excess water in the initial mix weakens the cured product by leaving voids behind. You end up with a less dense cured result. Usually when you mix cement it's a balancing act of using as little water as possible while maintaining workability and still having sufficient water to kick off the process. Then once it sets up you go crazy with the water keeping it hydrated while it cures.

This stuff is deliberately being mixed very wet...

Re: MIT engineers create an energy-storing supercapacitor from ancient materials

#80

Post by slow_typist »

pengaru wrote: post #79
slow_typist wrote: post #74

For 2 m^3 of the material you will need around 1 metric ton of cement. You need around 2.8 GJ to produce 1 t of cement. Therefore you need 63 GJ or 17500 kWh to produce a capacitor of 45 m^3 that can hold 10 kWh. (Omitting the 3% carbon in the mixture obv.) I hope the thing is really resistant and cycles forever without degradation. BTW cement production contributes substantial amounts to global carbon emissions.

Is your math accounting for the volume the added water occupies? The paper describes using excess water for deliberately creating voids the electrolyte can access. AIUI when mixing cement any excess water in the initial mix weakens the cured product by leaving voids behind. You end up with a less dense cured result. Usually when you mix cement it's a balancing act of using as little water as possible while maintainin…

Admitted, it could be less cement. But then the material could not be used for structural parts of a building.
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