A mesoporous, nanocrystalline, metal oxide construct particularly suited for capacitive energy storage that has an architecture with short diffusion path lengths and large surface areas and a method for production are provided. Energy density is substantially increased without compromising the capacitive charge storage kinetics and electrode demonstrates long term cycling stability. Charge storage devices with electrodes using the construct can use three different charge storage mechanisms immersed in an electrolyte: (1) cations can be stored in a thin double layer at the electrode/electrolyte interface (non-faradaic mechanism); (2) cations can interact with the bulk of an electroactive material which then undergoes a redox reaction or phase change, as in conventional batteries (faradaic mechanism); or (3) cations can electrochemically adsorb onto the surface of a material through charge transfer processes (faradaic mechanism).

In a method for manufacturing an energy storage device by applying welding to a container of the energy storage device, the method includes: arranging a jig on which wall surfaces are formed between two parts to be welded to which welding is applied; and welding the two parts to be welded while supplying a shield gas to the two parts to be welded from two different directions corresponding to the two parts to be welded.

In a capacitor using a capacitor element having an anode foil and a cathode foil wound with a separator interposed between the anode foil and the cathode foil, the separator includes a low insulation part having a low insulation function between the anode foil and the cathode foil, and the low insulation part may be included within a range of 90% in a central portion in a height direction of the capacitor element and within a range of 5 to 90% in a diametrical direction from the center of the capacitor element.

In a capacitor using a capacitor element having an anode foil and a cathode foil wound with a separator interposed between the anode foil and the cathode foil, the separator includes a low insulation part having a low insulation function between the anode foil and the cathode foil, and the low insulation part may be included within a range of 90% in a central portion in a height direction of the capacitor element and within a range of 5 to 90% in a diametrical direction from the center of the capacitor element.

Disclosed is a power storage element including a positive electrode current collector layer and a negative electrode current collector layer which are arranged on the same plane and can be formed through a simple process. The power storage element further includes a positive electrode active material layer on the positive electrode current collector layer; a negative electrode active material layer on the negative electrode current collector layer; and a solid electrolyte layer in contact with at least the positive electrode active material layer and the negative electrode active material layer. The positive electrode active material layer and the negative electrode active material layer are formed by oxidation treatment.

Disclosed is a power storage element including a positive electrode current collector layer and a negative electrode current collector layer which are arranged on the same plane and can be formed through a simple process. The power storage element further includes a positive electrode active material layer on the positive electrode current collector layer; a negative electrode active material layer on the negative electrode current collector layer; and a solid electrolyte layer in contact with at least the positive electrode active material layer and the negative electrode active material layer. The positive electrode active material layer and the negative electrode active material layer are formed by oxidation treatment.

An inspection device (20) for inspecting a structure body (10) including a pair of electrodes and a separator disposed between the pair of electrodes is provided, the inspection device (20) includes: a measurement unit (30) including a direct-current constant voltage generator (32) that generates a constant inspection voltage applied to the pair of electrodes, and a detection circuit (34) that detects a current value between the pair of electrodes resulting from the application of the inspection voltage; and a processing unit (50) that determines whether the structure body (10) is defective or non-defective based on the detected current value, and the processing unit (50) has a function that, if two or more points at which a ratio (ΔI/Δt) of a current value variation amount (ΔI) to a time variation amount (Δt) varies from a value of no less than 0 to a negative value are observed or no point at which the ratio (ΔI/Δt) varies from a value of no less than 0 to a negative value is observed during a period of time immediately after the application of the inspection voltage until the current value becomes constant, determines the structure body (10) as a defective product, and an auxiliary function that obtains a peak current value I.sub.peak, a peak current appearing time t.sub.peak and a current area S.sub.I of a current waveform representing variation in current value I over passage of time t, and if any one of the peak current value I.sub.peak, the peak current appearing time t.sub.peak and the current area S.sub.I deviates from a preset threshold value including an upper limit value and a lower limit value, determines the structure body as a defective product.

A supercapacitor contains the zwitterionic polymer hydrogel electrolyte. A change rate of a capacitance retention of the supercapacitor, relative to a specific area capacity at 25° C. is less than 25% at extreme temperature. When temperature is increased to 60° C. or reduced to −30° C. the specific area capacity is changed to 178 mF cm.sup.−2 and 134 mF cm.sup.−2, which are 104% and 78% of that at 25° C. indicating an excellent electrochemical property at the extreme temperature.

A supercapacitor contains the zwitterionic polymer hydrogel electrolyte. A change rate of a capacitance retention of the supercapacitor, relative to a specific area capacity at 25° C. is less than 25% at extreme temperature. When temperature is increased to 60° C. or reduced to −30° C. the specific area capacity is changed to 178 mF cm.sup.−2 and 134 mF cm.sup.−2, which are 104% and 78% of that at 25° C. indicating an excellent electrochemical property at the extreme temperature.

Solid-state supercapacitors and microsupercapacitors comprising printed graphene electrodes and related methods of preparation.