In theory you could store an almost unlimited amount of power in a cap made of super conductors and super dielectrics.
So "in theory" you could store enough electricity in a sugar cube to drive for years.
In reality neither material would be perfect setting upper limits. Still EESTOR's super caps at 3600 V can complete with lithium Ion batteries in power to weight already.
There is no reason why we don't have 1MV super caps.
There is no one looking at super conductors or dielectrics for caps right now. Most are building supercaps that are only good for 1 Volt or very low voltages, which means the dielectrics are super thin and therefor must be almost perfect in order not the short out.
The thicker the dielectrics the less perfection on the nano scale is needed.
I bet in 2015 we are still driving gasoline based cars and almost nothing would have changed, but just a lot of political rhetoric as people die from climate change.
They aren't using the best supercaps, just the cheapest ones.
In the EEStor patent they were claiming 610 V/um breakdown voltages for Aluminum coated CMBT, this is astonishing since I was having a hard time finding anything else above 100 V/um with Mica at 140 to 210 V/um
1100 V/um for bulk alumina which is basically Aluminum oxide also know as Saphire.
But can you really get this in a bulk manufactured product?
Perovskite with High Dielectric Constant May Lead to High Performance Capacitors
Perovskite crystals, seems there are some geometric structures that make this material Super-K CCTO CaCu3Ti4O12 a very good dielectric, it has some interesting properties at low temeratures too.
Physicists discover the 'superinsulator'
thin films of titanium nitride cooled towards absolute zero in a magnetic field. Although the material is usually a superconductor, in which electrical current can propagate without resistance, the team have found that in these conditions the material’s resistance rises to infinity
EEStor Issued a Patent For Its Supercapacitor
US Patent 7466536 EEStor
Utilization of poly(ethylene terephthalate) plastic and composition-modified barium titanate powders in a matrix that allows polarization and the use of integrated-circuit technologies for the production of lightweight ultrahigh electrical energy storage units (EESU)
TheEEStory.com News, Reviews and Discussion of EEStor Inc.
US Patent 7251118 Nonplanar-Nanostructures
Method and apparatus for large scale storage of electrical potentialNonplanar-Nanostructures company web site
Basic Physics of PARALLEL-PLATE CAPACITORS
Tecate Group - ultracapacitors