There was an article I found from late last year about an interesting supercapacitor development. Imagine being able to charge your Model S, powered by supercapacitors, in just 16 seconds! And they could last 27 years or longer (10,000 cycles).
More here:
Charged EVs | Graphene supercapacitor packs basketball court-size surface area into one gram
More here:
Charged EVs | Graphene supercapacitor packs basketball court-size surface area into one gram