Abstract: A hybrid lead acid battery and porous carbon supercapacitor energy storage device is asymmetrically supercapacitive and comprises at least one lead electrode, at least two carbon-based electrodes, a separator, a casing, and an acid electrolyte. The lead electrode has a non-conductive sheet of porous material which envelops a lead based mass and lead-based current collector. Each carbon-based electrode is moderately conductive, having a sheet of highly conductive material between two sheets of electrically conductive shield material, and highly porous carbon adhered to the highly conductive material. The casing applies and maintains compression forces against the faces of the electrodes, and provides a void space in the interior of an assembled energy storage device.