NOVELTY - Charge storage device (I), comprises a nanostructured, mesoporous material.    USE - (I) is useful as capacitive storage device, preferably cell (claimed).    ADVANTAGE - (I): provides significantly higher power densities than those found in batteries, without compromising energy density and sacrificing the high rate charging/discharging properties of capacitors; and has long term cycling stability.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a charge storage device, comprising: a nanocrystalline, mesoporous, material, where the material comprises many pores, and the pores have nanocrystal walls;    (2) a method for producing a nanostructured, mesoporous material construct, comprising: synthesizing many metal oxide nanocrystals; templating the metal oxide nanocrystals with a polymer template to form a templated film; disposing the templated film on a substrate; crystallizing the templated film; and removing the template from the templated film to provide a mesoporous nanocrystalline construct;    (3) a product produced by the above method;    (4) a method for producing a capacitive storage device, comprising: synthesizing many metal oxide nanocrystals; templating the metal oxide nanocrystals with a polymer template to form a templated film; disposing the templated film on a first electrically conductive substrate and a second electrically conductive substrate; crystallizing the templated films on the substrates; removing the template from the templated films to provide a mesoporous nanocrystalline electrode on the substrates; joining the electrodes of the first and second substrates to a separator (16) to form a cell (10); and exposing the cell to an electrolyte; and    (5) a capacitive storage device prepared by the above method.    DESCRIPTION OF DRAWING(S) - The figure is a schematic side view diagram of a double-layer capacitor cell.    Supercapacitor cell (10)    First mesoporous electrode layer (12)    Second mesoporous electrode layer (14)    Dielectric separator plate (16)    Positive current collector (18)