from Hacker News

Supercapacitors Batteries charges in seconds without degrading

by Ideabile on 11/23/16, 8:28 PM with 98 comments

• by gus_massa on 11/23/16, 11:13 PM

  The size of the battery varies from phone to phone, but let's choose 3000mAh as a typical value so the battery is enough for a full day.

  If you want to charge it in "seconds", let's use 60 seconds as an upper bound.

  So if the charger has a 100% efficiency, then it has to provide 3000mAh/60sec = 3000mAh * 3600 sec/h / 60sec = 180000mA = 18A.

  An USB can provide between 0.1A and 0.9A. For comparison, a typical plug in a home can provide 10A. So to charge the phone you will need some big connector, not a tiny microUSB like connector.

  But it's worse. From the article:

  > "If they were to replace the batteries with these supercapacitors, you could charge your mobile phone in a few seconds and you wouldn't need to charge it again for over a week," said Nitin Choudhary, a postdoctoral associate who conducted much of the research published recently in the academic journal ACS Nano.

  To recharge the phone once a week, I guess you will need a 20000mAH battery, and a few seconds is something like 5, so the connector must survive to 1000A, that is a ridiculous current.

• by daveguy on 11/23/16, 10:53 PM

  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?

• by gravypod on 11/23/16, 10:48 PM

  Coincidentally they also like to discharge in seconds!

• by kylehotchkiss on 11/24/16, 12:25 AM

  The scary part is that touching the two connectors of a supercapacitor is an instant discharge. Which might prove pretty dangerous.

• by seesomesense on 11/24/16, 4:39 AM

  The original article is High-Performance One-Body Core/Shell Nanowire Supercapacitor Enabled by Conformal Growth of Capacitive 2D WS2 Layers DOI: 10.1021/acsnano.6b06111

  and is available at the usual places.

• by sandworm101 on 11/24/16, 1:42 AM

  >>> Anyone with a smartphone knows the problem: After 18 months or so, it holds a charge for less and less time as the battery begins to degrade.

  Really? That's still a thing? These aren't nicads. I've found that my phone doesn't report full charge as often, but it still lasts for a similar amount of time. My 5+yo netbook's battery is still reporting 80% of its design capacity.

  Imho, such apparently dramatic falls in capacity often have more to do with running apps rather than physical degradation of the battery. Talk to me after a reset to factory settings.

• by Tepix on 11/24/16, 1:21 PM

  Sorry for being cynical but I'll get excited only once I can actually buy this latest battery breakthrough, not when it is still X years away.

• by AndrewDucker on 11/24/16, 1:01 PM

  I thought that capacitors also discharged incredibly quickly. Can a capacitor be used like a battery?

• by mrfusion on 11/24/16, 12:51 AM

  If this is true it would be revolutionary right?