oil companies will kill this for sure
http://www.gizmag.com/nanoscale-supercapacitor/11297/
these super capacitors give 3000 wH/kg,
the article says that gas engines are 15% efficient tank to wheel giving it 1800 wh/kg
these capacitors will be better than gas/diesel/conventional chem batteries in every single possible way, faster refill/recharge, longer range, cheaper, cleaner, more power and even shape, its flexible so it can be any shape really, rectangle, round, cylindrical, whatever you need.
the only thing holding us back from this technology is greed and money, oil companies want to maintain their hold, everyone is poor and cant afford to spend the money on RD/infrastructure/etc,