Researchers make a supercapacitor from water, cement, and carbon black

&gt; For now, the concrete supercapacitor can store a little under 300 watt-hours per cubic metre – enough to power a 10-watt LED lightbulb for 30 hours.<p>&gt; The power output &quot;may seem low compared to conventional batteries, [but] a foundation with 30-40 cubic metres (1,060-1,410 cubic feet) of concrete could be sufficient to meet the daily energy needs of a residential house&quot;, says Stefaniuk.<p>This made me suspicious, because it sounded too low. But it turns out it&#x27;s true ... for an average British home that&#x27;s heavily dependent on gas.<p>40 m^3 * 300 watt-hours&#x2F;m^3 = 12 kwh. I.e. 500 watts for a whole day.<p>Apparently the average American residential electricity use is 10,791 kwh&#x2F;year, which is ~1,231 watts, whereas the average British home is only 2,700 kwh&#x2F;year which is ~308 watts. I had no idea that the difference was so large.<p><a href="https:&#x2F;&#x2F;www.eia.gov&#x2F;tools&#x2F;faqs&#x2F;faq.php?id=97&amp;t=3" rel="nofollow">https:&#x2F;&#x2F;www.eia.gov&#x2F;tools&#x2F;faqs&#x2F;faq.php?id=97&amp;t=3</a><p><a href="https:&#x2F;&#x2F;www.britishgas.co.uk&#x2F;energy&#x2F;guides&#x2F;average-bill.html" rel="nofollow">https:&#x2F;&#x2F;www.britishgas.co.uk&#x2F;energy&#x2F;guides&#x2F;average-bill.html</a>

I&#x27;m happy this invention is still in the news cycle after the initial announcement 10 months ago...<p>[0] <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=36958531">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=36958531</a><p>[1] <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=36993411">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=36993411</a><p>[2] <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=36951089">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=36951089</a><p>While I&#x27;m fairly dubious about the proposed dual-purpose structural implementation of this material -- if this works at scale it would be a boon for low cost DIY local energy storage in the developing world and remote areas in other places.<p>The idea that someone with minimal education&#x2F;training can construct a durable electrical storage solution using commonly available materials and techniques is an absolute game changer!!

The most relevant (practical) questions to me are, how does this capacitor behave long-term? How does it fare over a large number of charge&#x2F;discharge cycles? I&#x27;d like to assume that, since it&#x27;s not a battery, thus not based on chemical process for energy storage, it will retain its initial performance for a long time, but the question is - how long? A human generation (i.e. 25-30 years)? Or maybe longer, as for at least ten generations? That would directly affect the demand for long term investments in the construction sector. And if things may sound rosy from its storage capacity capability, if it will get used for combined structural and energy storage use, what long term impact on structural properties may render this dual use?

&gt; larger versions, including one up to 45 cubic metres (1,590 cubic feet) in size that would be able store around 10kWh of energy needed to power to power a house for a day.<p>45 cubic meter is a cube with side 3.56 meter. That is not large at all. Especially, if it can be sunk into the ground. I assume septic tanks are also about the same size.<p>Paper, if anyone interested: <a href="https:&#x2F;&#x2F;www.pnas.org&#x2F;doi&#x2F;full&#x2F;10.1073&#x2F;pnas.2304318120?doi=10.1073%2Fpnas.2304318120" rel="nofollow">https:&#x2F;&#x2F;www.pnas.org&#x2F;doi&#x2F;full&#x2F;10.1073&#x2F;pnas.2304318120?doi=10...</a>

I’m not sure if I’ve misread the article but it seemed unclear as to whether the concrete needed to remain soaked in potassium chloride? Surely keeping a whole foundation soaked indefinitely would be impractical?

I see these things as a waste of time and resources. We already have all sorts of ways of storing energy, from chemical to mechanical to biological, which are known to work. There are myriad open questions regarding the practicalities of incorporating a battery as the frame of your house, and given the &quot;technological inertia&quot; of the building sector and its regulations, it would take several decades before we even start experimenting with this in real houses. Meanwhile, the world burns and we increase our energy consumption. Again, a waste of time and resources.

When looking at the diagrams for an ideal wall [1], I am reminded of diagrams of capacitors from Physics classes. This got me to thinking that two conductive vapor barrier with a dialectic&#x2F;insulator sandwiched between them, such as aerogel, would work well as a wall element, and a capacitor storage device for a house.<p>[1][<a href="https:&#x2F;&#x2F;buildingscience.com&#x2F;documents&#x2F;insights&#x2F;bsi-001-the-perfect-wall" rel="nofollow">https:&#x2F;&#x2F;buildingscience.com&#x2F;documents&#x2F;insights&#x2F;bsi-001-the-p...</a>]

I don&#x27;t want to be a naysayer, but I do have to wonder, are there any risks associated with making the walls themselves store large quantities of energy?<p>I&#x27;m thinking fire hazards or shorts associated with, say, hanging a framed picture on the wall (or anything else that would involve drilling in the concrete)

Why not use this for a way more obvious application such as corrosion protection? You can then mix in the sacrificial anode as a powder instead of having discrete anodes.

That&#x27;s a very poor article. It doesn&#x27;t explain what the potassium chloride is for.<p>It&#x27;s interesting but you can store a lot of thermal energy in concrete. The heat capacity is 1050 J&#x2F;(kg.K). One cubic meter of concrete is about 2 400 kg and the heat capacity is roughly 1 x 10^3 J&#x2F;(kg.K) so raising the temperature by just 1 degree C would store 2.4 x 10^6 J. That&#x27;s 666 Wh.<p>Twice the energy storage for only one kelvin temperature rise with no technological breakthroughs needed. Granted it&#x27;s not electricity but in temperate and colder climates a lot of the energy needed in a home is heat.<p>Still a very interesting idea and if it can be made to work cheaply enough even at the storage capacity they quote it would add a lot of flexibility to the energy system.

This is the research paper linked in the article.<p><a href="https:&#x2F;&#x2F;www.pnas.org&#x2F;doi&#x2F;10.1073&#x2F;pnas.2304318120" rel="nofollow">https:&#x2F;&#x2F;www.pnas.org&#x2F;doi&#x2F;10.1073&#x2F;pnas.2304318120</a>

&gt; &quot;<i>Supercapacitors are not perfect. Existing iterations discharge power quickly, and are not ideal for steady output, which would be needed to power a house throughout the day.</i>&quot;<p>Could someone kindly explain to me how this works?<p>For example, if you had an empty lithium battery which can store X amount of power, and a fully charged supercapacitor which holds 10X, can you charge the lithium battery to full and leave 9X in the supercapacitor?<p>If no, why not and how do you (both safely and usefully) get energy out of a supercapacitor? Or if yes, could a relatively small battery between the SC and a house act as a buffer to stop it mattering that the SC discharges &quot;too quickly and unsteadily&quot;?

So what happens if your house capacitor blows?