A structural electrochemical capacitor that includes at least one pair of electrodes and a solid electrolytic material disposed between the electrodes which, taken collectively, have sufficient mechanical strength to allow the electrochemical capacitor to be used as a structural component of an article of manufacture is described. The present invention also describes a method of capacitively storing electrical energy and conserving mass and/or volume in a device that includes the steps of: fabricating portions of the structure of a device with high-strength structural electrochemical capacitor that includes at least one pair of electrodes and a body of solid electrolytic material disposed between said electrodes wherein the body of solid electrolytic material accounts for a majority of the mass of a structural element or a majority of the volume of a structural element in the device.