Could be interesting, though it's a few years down the road. I could see Tesla being the first to try and adapt this technology to EVs, but I think it would fit a niche. Because capacitors bleed power, they wouldn't be a good choice for normal driving. However, if you had a 100 kWh module that you could drop in and charge to near 100% capacity at, say, 400 kW, it would make an excellent option for long-distance driving.
Outside of improving batteries (size and charge rates), a few options already exist:
Single-use air batteries
Liquid redox batteries that can flush the system with recharged fluid
The energy density of modern supercapacitors has improved over what the article posted of 5 wH per kg. Maxwell has units that have 7.4 Wh/kg, and will be improving as chemical and mechanical technology allows it. As an example, here is a datasheet of Maxwell's largest supercapacitor (3,400 Farads or 3.4 kF): http://www.maxwell.com/images/documents/K2_2_85V_DS_3000619EN_3_.pdf
Given that each unit stores 3.9 wH (14 kJ) of energy, you can easily calculate how many units are needed for any application. Add the benefit that the supercapacitors never need cooling (or heating!) to maintain their charge.
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