Patent ID: 8564932

Claim:
A supercapacitor comprising; a closed chamber which is equipped with means for exchanging a gas with the external environment; and in which two electrodes, each carrying a layer of activated carbon having a high specific surface area are placed while being separated by a separator, the separator and the electrodes being impregnated with an electrolyte, wherein the means for exchanging a gas has a membrane which is permeable to hydrogen and its isotopes and impermeable to gas species which have a cross section greater than or equal to 0.3 nm, at a temperature of between −50° C. and 100° C., and in that the membrane has a surface area S (in m 2 ) and a thickness e (in m), and in that it includes a material which is selected from the group consisting of metals and metal alloys, and the intrinsic permeability Φ of which (in mol.m −1 .s −1 Pa −1/2 ) is selective with respect to hydrogen and has a value such that 10 −15 mol.s −1 .Pa −1/2 ≦(Φ*S)/e≦10 −9 mol.s −1 .Pa −1/2 .