Remember last years announcement from Stanford of an amazing battery breakthrough? It was announced by Yi Cui, a Stanford Professor. The same guy has a new announcement of battery material that is painted on regular paper and can make an amazing battery.
Stanford prof pops lid on paint-on battery tech
As a battery, its energy/weight ratio isn't very impressive - just 7.5 watt-hours/kg when "weight of all of the dead components is considered", or 30-47 Wh/kg on its own, still less than typical lead-acid jobs. the paint can handle very rapid discharge rates, 200 kilowatts/kg, and CUI says it's very durable too; able to stake 40,000 charge/discharge cycles, maybe ten times as much as a normal li-ion job.
Printable, Moldable Batteries Made From Paper and Nanotubes