In one embodiment a charge storage device includes first (110) and second (120) electrically conductive structures separated from each other by a separator (130). At least one of the first and second electrically conductive structures includes a porous structure containing multiple channels (111, 121). Each one of the channels has an opening (112, 122) to a surface (115, 125) of the porous structure. In another embodiment the charge storage device includes multiple nanostructures (610) and an electrolyte (650) in physical contact with at least some of the nanostructures. A material (615) having a dielectric constant of at least 3.9 may be located between the electrolyte and the nanostructures.