A capacitor may be configured with a dielectric laminate disposed on ordered or non-ordered structures. Materials for the dielectric laminate have high dielectric constant and reduce leakage current to increase breakdown voltage of the device. These materials may include titanium dioxide (TiO.sub.2) and silicon dioxide (SiO.sub.2). In one implementation, the capacitor may reside on a substrate. The capacitor may have structure (e.g., nano-tubes, nano-holes, etc;) disposed on the substrate having a surface area greater than the surface area of the substrate and a laminate conformally coating the structure, the laminate comprising a first layer and a second layer with materials that configure the capacitor with an energy density of at least 60 Wh/Kg.

The purpose of the present technology is to provide an electrode for power storage device and a power storage device that make it possible to involve more lithium ions in a charge-discharge reaction. A lithium-ion secondary battery has: a positive electrode current collector; a positive electrode active material layer on the positive electrode current collector; a negative electrode current collector; and a negative electrode active material layer on the negative electrode current collector. The negative electrode active material layer has a carbon nanowall. The carbon nanowall is capable of involving, in the charge-discharge reaction, two or more lithium ions per carbon atom in a single charge or discharge.

The purpose of the present technology is to provide an electrode for power storage device and a power storage device that make it possible to involve more lithium ions in a charge-discharge reaction. A lithium-ion secondary battery has: a positive electrode current collector; a positive electrode active material layer on the positive electrode current collector; a negative electrode current collector; and a negative electrode active material layer on the negative electrode current collector. The negative electrode active material layer has a carbon nanowall. The carbon nanowall is capable of involving, in the charge-discharge reaction, two or more lithium ions per carbon atom in a single charge or discharge.

An electrochemical device includes a positive electrode including a positive current collector and a positive electrode material layer supported on the positive current collector, a negative electrode, and an electrolytic solution. The positive electrode material layer includes a conductive polymer, and a surface roughness (Ra) of the positive current collector is in a range from 0.7 μm to 1.7 μm, inclusive.

A plate includes a current collector, an intermediate layer layered on the current collector, and an active material layer layered on the intermediate layer. The intermediate layer contains conductive particles and insulating particles. At least a portion of an end edge of the intermediate layer is not covered with the active material layer. The intermediate layer hays a higher mass content of the insulating particles in a region not covered with the active material layer than that in a region covered with the active material layer.

Microsupercapacitors (MSCs), as well as methods of fabricating the same and methods of using the same, are provided. An MSC can include interdigitated microelectrodes having reduced graphene oxide (rGO) (e.g., vertically aligned nanosheets thereof) disposed on upper surfaces of the microelectrodes. The MSC can be fabricated by preparing a micro-current collector (MCC) comprising the interdigitated microelectrodes using photolithography and then performing a bipolar electrochemistry process on the MCC to deposit rGO on the upper surfaces of the interdigitated microelectrodes (e.g., in a single-step in situ exfoliation, reduction, and deposition).

The power storage device comprises an electrode assembly including a positive electrode, a separator, and a negative electrode, and an electrolyte solution. The negative electrode comprises a negative electrode current collector and a negative electrode active material layer. The active material layer comprises a surplus region A not facing the positive electrode active material layer, an end region B facing a region in the positive electrode active material layer, the region extending from an end of the positive electrode active material layer toward a center of the positive electrode active material layer by a length of 5% of a length from the center to the end, and a center region C. A negative electrode potential VA and a negative electrode potential VC after the positive electrode and the negative electrode are short-circuited satisfy Formulas below: (1): VA≤2.0 V, (2): VC≤1.0 V, (3): VA/VC≥0.7.

The power storage device comprises an electrode assembly including a positive electrode, a separator, and a negative electrode, and an electrolyte solution. The negative electrode comprises a negative electrode current collector and a negative electrode active material layer. The active material layer comprises a surplus region A not facing the positive electrode active material layer, an end region B facing a region in the positive electrode active material layer, the region extending from an end of the positive electrode active material layer toward a center of the positive electrode active material layer by a length of 5% of a length from the center to the end, and a center region C. A negative electrode potential VA and a negative electrode potential VC after the positive electrode and the negative electrode are short-circuited satisfy Formulas below: (1): VA≤2.0 V, (2): VC≤1.0 V, (3): VA/VC≥0.7.

An electrochemical device of the present invention includes a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode. The positive electrode includes a positive current collector containing aluminum, a positive electrode material layer containing a conductive polymer, and an aluminum oxide layer disposed on a surface of the positive current collector. The aluminum oxide layer contains fluorine.

An electrochemical device of the present invention includes a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode. The positive electrode includes a positive current collector containing aluminum, a positive electrode material layer containing a conductive polymer, and an aluminum oxide layer disposed on a surface of the positive current collector. The aluminum oxide layer contains fluorine.