I've been researching into the development of electrical power units for Automotives (motorsports in particular, as I participate in my Uni's Formula Student team) and have started by looking into the applications of supercapacitors for energy storage purposes. I'm seeing a pattern, were all supercapacitors currently on the market are rated at max, 2.7V (with some pushing close to 3.0V) without any real reason why.
Compared to standard electrolytic capacitors (which I've viewed types that can withstand 1000V comfortably) I understand that the construction is different however I'm not exactly sure why this has such a drastic effect on the max voltage. Would there be anything on the quantum level that stops a supercapacitor having a rated voltage greater?
My suggestion is that maybe the Helmholtz regions that hold the capacitance has an effect on the maximum voltage that can be but I'm not entirely sure (just an educated guess)