An asymmetric nanocomposite supercapacitor and a method of making the asymmetric nanocomposite supercapacitor. The asymmetric nanocomposite supercapacitor includes a negative electrode with monoclinic tungsten oxide (m-WO.sub.3) nanoplates, and a binding compound coated on one face of a substrate, and a positive electrode with a carbonaceous material and a binding compound coated on one face of a substrate. Where the face of the positive electrode and the face of the negative electrode coated with the carbonaceous material and m-WO.sub.3 nanoplates, respectively, are separated by and in direct contact with a porous separator.

A solid electrolytic capacitor that includes a plurality of capacitor elements each including an anode portion, a dielectric layer, and a cathode portion having a solid electrolyte layer and a current collector layer; a leading conductor layer; an insulating resin body; a first external electrode; and a second external electrode. The plurality of capacitor elements are stacked in layers, with mutually adjacent capacitor elements having their respective current collector layers connected to each other. The current collector layer of only the capacitor element adjacent to the leading conductor layer is connected to the leading conductor layer. The first external electrode is connected to the leading conductor layer at the first end surface.

A lithium-cobalt-based composite oxide used for a positive electrode active material of an electrochemical device, wherein the lithium-cobalt-based composite oxide has elutable fluoride ions, the elutable fluoride ions being eluted to an eluate when the lithium-cobalt-based composite oxide is dispersed to ultrapure water, in a mass ratio of 500 ppm or more and 15000 ppm or less in comparison with the lithium-cobalt-based composite oxide, and the lithium-cobalt-based composite oxide has a composition shown by the following general formula (1): Li.sub.1-xCo.sub.1-zM.sub.zO.sub.2-aF.sub.a (−0.1≦x<1, 0≦z<1, 0≦a<2) . . . (1) (wherein, M represents one or more kinds of metal element selected from the group of Mn, Ni, Fe, V, Cr, Al, Nb, Ti, Cu, and Zn).

A nanocomposite electrode and a method of making the nanocomposite. The nanocomposite electrode includes an electrode substrate, nitrogen-doped molybdenum carbide nanosheets, at least one electrolyte, at least one binding compound, and at least one conductive additive. The electrode substrate is coated with a mixture of the nitrogen-doped molybdenum carbide nanosheets, at least one binding compound, at least one conductive additive, and at least one electrolyte, where the electrolyte penetrates the pores of the nitrogen-doped molybdenum carbide nanosheets, and where the nitrogen-doped molybdenum carbide nanosheets are an outer layer of the electrode.

This disclosure provides a unique approach for the synthesis of non-stoichiometric, mesoporous metal oxides with nano-sized crystalline wall. The as-synthesized mesoporous metal oxide is very active and stable (durability>11 h) electocatalyst in both acidic and alkaline conditions. The intrinsic mesoporous metal oxide serves as an electrocatalyst without the assistant of carbon materials, noble metals, or other materials, which are widely used in previously developed systems. The as-synthesized mesoporous metal oxide has large accessible pores (2-50 nm), which are able to facilitate mass transport and charge transfer. The as-synthesized mesoporous metal oxide requires a low overpotential and is oxygen deficient. Oxygen vacancies and mesoporosity served as key factors for excellent performance.

This disclosure provides a unique approach for the synthesis of non-stoichiometric, mesoporous metal oxides with nano-sized crystalline wall. The as-synthesized mesoporous metal oxide is very active and stable (durability>11 h) electocatalyst in both acidic and alkaline conditions. The intrinsic mesoporous metal oxide serves as an electrocatalyst without the assistant of carbon materials, noble metals, or other materials, which are widely used in previously developed systems. The as-synthesized mesoporous metal oxide has large accessible pores (2-50 nm), which are able to facilitate mass transport and charge transfer. The as-synthesized mesoporous metal oxide requires a low overpotential and is oxygen deficient. Oxygen vacancies and mesoporosity served as key factors for excellent performance.

An electrochemical device electrode pertaining to one mode of the present invention has a current collector, an aluminum oxide layer, a conductive layer, and an active material layer. The current collector is an aluminum foil. The aluminum oxide layer is formed on a principle surface of the current collector and contains aluminum hydroxide and aluminum oxide. The conductive layer is formed on the aluminum oxide layer and contains conductive material, while the active material layer is formed on the conductive layer.

An electrochemical device electrode pertaining to one mode of the present invention has a current collector, an aluminum oxide layer, a conductive layer, and an active material layer. The current collector is an aluminum foil. The aluminum oxide layer is formed on a principle surface of the current collector and contains aluminum hydroxide and aluminum oxide. The conductive layer is formed on the aluminum oxide layer and contains conductive material, while the active material layer is formed on the conductive layer.

A printed energy storage device includes a first electrode, a second electrode, and a separator between the first and the second electrode. At least one of the first electrode, the second electrode, and the separator includes frustules, for example of diatoms. The frustules may have a uniform or substantially uniform property or attribute such as shape, dimension, and/or porosity. A property or attribute of the frustules can also be modified by applying or forming a surface modifying structure and/or material to a surface of the frustules. A membrane for an energy storage device includes frustules. An ink for a printed film includes frustules.

A printed energy storage device includes a first electrode, a second electrode, and a separator between the first and the second electrode. At least one of the first electrode, the second electrode, and the separator includes frustules, for example of diatoms. The frustules may have a uniform or substantially uniform property or attribute such as shape, dimension, and/or porosity. A property or attribute of the frustules can also be modified by applying or forming a surface modifying structure and/or material to a surface of the frustules. A membrane for an energy storage device includes frustules. An ink for a printed film includes frustules.