Devices that convert heat into electricity, and methods for a fabrication of the same are provided. The asymmetric thermo-electrochemical capacitor uses a GO-based positive electrode and a battery-type negative electrode to open up the operating voltage window and enhance the electrical discharge capacity for converting low-grade heat into electricity with excellent efficiency, fast thermo-charging time, and stable cycles. The thermo-electrochemical device includes a carbon-based positive electrode, a conductive polymer or a metal-organic framework as negative electrode, a current collector, and a porous separator.

Devices that convert heat into electricity, and methods for a fabrication of the same are provided. The asymmetric thermo-electrochemical capacitor uses a GO-based positive electrode and a battery-type negative electrode to open up the operating voltage window and enhance the electrical discharge capacity for converting low-grade heat into electricity with excellent efficiency, fast thermo-charging time, and stable cycles. The thermo-electrochemical device includes a carbon-based positive electrode, a conductive polymer or a metal-organic framework as negative electrode, a current collector, and a porous separator.

The formation method of graphene includes the steps of forming a layer including graphene oxide over a first conductive layer; and supplying a potential at which the reduction reaction of the graphene oxide occurs to the first conductive layer in an electrolyte where the first conductive layer as a working electrode and a second conductive layer with a as a counter electrode are immersed. A manufacturing method of a power storage device including at least a positive electrode, a negative electrode, an electrolyte, and a separator includes a step of forming graphene for an active material layer of one of or both the positive electrode and the negative electrode by the formation method.

The formation method of graphene includes the steps of forming a layer including graphene oxide over a first conductive layer; and supplying a potential at which the reduction reaction of the graphene oxide occurs to the first conductive layer in an electrolyte where the first conductive layer as a working electrode and a second conductive layer with a as a counter electrode are immersed. A manufacturing method of a power storage device including at least a positive electrode, a negative electrode, an electrolyte, and a separator includes a step of forming graphene for an active material layer of one of or both the positive electrode and the negative electrode by the formation method.

A wet tantalum electrolytic capacitor containing a cathode, fluidic working electrolyte, and anode formed from an anodically oxidized sintered porous tantalum pellet is described. The pellet is formed from a pressed tantalum powder. The tantalum powder is formed by reacting a tantalum oxide compound, for example, tantalum pentoxide, with a reducing agent that contains a metal having an oxidation state of 2 or more, for example, magnesium. The resulting tantalum powder is nodular or angular and has a specific charge that ranges from about 9,000 μF*V/g to about 11,000 μF*V/g. Using this powder, wet tantalum electrolytic capacitors have breakdown voltages that ranges from about 340 volts to about 450 volts. This makes the electrolytic capacitors ideal for use in an implantable medical device.

A wet tantalum electrolytic capacitor containing a cathode, fluidic working electrolyte, and anode formed from an anodically oxidized sintered porous tantalum pellet is described. The pellet is formed from a pressed tantalum powder. The tantalum powder is formed by reacting a tantalum oxide compound, for example, tantalum pentoxide, with a reducing agent that contains a metal having an oxidation state of 2 or more, for example, magnesium. The resulting tantalum powder is nodular or angular and has a specific charge that ranges from about 9,000 μF*V/g to about 11,000 μF*V/g. Using this powder, wet tantalum electrolytic capacitors have breakdown voltages that ranges from about 340 volts to about 450 volts. This makes the electrolytic capacitors ideal for use in an implantable medical device.

An electrolytic capacitor includes an anode body including a dielectric layer, a cathode body, and a conductive polymer layer and a liquid component that are disposed between the anode body and the cathode body. The cathode body includes a base material part having an outer surface that is roughened surface and has a pore opened at the outer surface, and an inorganic conductive layer covering at least a part of the outer surface. The base material part includes a first coating layer disposed along at least a part of inner wall of the pore. The first coating layer contains phosphorus.

An electrolytic capacitor includes an anode body including a dielectric layer, a cathode body, and a conductive polymer layer and a liquid component that are disposed between the anode body and the cathode body. The cathode body includes a base material part having an outer surface that is roughened surface and has a pore opened at the outer surface, and an inorganic conductive layer covering at least a part of the outer surface. The base material part includes a first coating layer disposed along at least a part of inner wall of the pore. The first coating layer contains phosphorus.

A method for producing an electrode for an electrolytic capacitor, the method including: a chemical conversion step of allowing a current to flow through a metal material containing a valve metal in a chemical conversion solution containing an electrolyte, to form an oxide film on a surface of the metal material, wherein the chemical conversion solution contains a nitrate-based compound as the electrolyte at a concentration of 0.03 mass % or more, and a phosphorus compound concentration in the chemical conversion solution is less than 0 01 mass %.

A method for producing an electrode for an electrolytic capacitor, the method including: a chemical conversion step of allowing a current to flow through a metal material containing a valve metal in a chemical conversion solution containing an electrolyte, to form an oxide film on a surface of the metal material, wherein the chemical conversion solution contains a nitrate-based compound as the electrolyte at a concentration of 0.03 mass % or more, and a phosphorus compound concentration in the chemical conversion solution is less than 0 01 mass %.