A quantum supercapacitor having nanostrucutured material located between electrodes. The material includes clusters with tunnel-transparent gaps. The clusters have sizes within the range of 7.2517 nm.ltoreq.r.ltoreq.29.0068 nm, at which the resonant characteristics of the electron are exhibited. The size is determined by the circular radius of the electronic wave according to the formula r.sub.0=/(m.sub.e.alpha..sup.2c)=7.2517 nm (Plank constant , electron mass m.sub.e, fine structure constant .alpha.=1/137,036, speed of light c). The cluster size is set within the range r.sub.0.ltoreq.4r.sub.0; the width of the tunnel-transparent gap being .ltoreq.r.sub.0=7.2517 nm. The energy in the supercapacitor is stored by means of controlled breakthrough of the material--a dielectric, with subsequent restoring thereof. The energy is stored uniformly along the whole volume of the material due to the resonant coupling of the electrons on the cluster. The maximum stored specific energy stored is 1.66 MJ/kg.