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.<p>If you want to charge it in "seconds", let's use 60 seconds as an upper bound.<p>So if the charger has a 100% efficiency, then it has to provide 3000mAh/60sec = 3000mAh * 3600 sec/h / 60sec = 180000mA = 18A.<p>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.<p>But it's worse. From the article:<p>> <i>"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.</i><p>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.