Classic modern reporting - doesn't link to the source or even cite the paper.
Here's the source: http://www.nature.com/nmat/journal/vaop/ncurrent/pdf/nmat476...
Web version: http://www.nature.com/nmat/journal/vaop/ncurrent/full/nmat47...
Here's the source: http://www.nature.com/nmat/journal/vaop/ncurrent/pdf/nmat476...
Web version: http://www.nature.com/nmat/journal/vaop/ncurrent/full/nmat47...
I quote:
> ... although conventional batteries have a slower recharging time, the fact that they maintain their charging capacity over a longer period because makes Li-ion the more efficient choice over carbon-based supercapacitors.
Nope. That's not it.