Disclosed are an insulating material (high-k layer) which includes a fiber assembly mainly composed of a cellulose nanofiber, and an electroconductive metal material supported by the fiber assembly; and a passive element (capacitor) which includes a high-k layer which is composed of the insulating material, and an electroconductive part stacked on the high-k layer.

Disclosed are an insulating material (high-k layer) which includes a fiber assembly mainly composed of a cellulose nanofiber, and an electroconductive metal material supported by the fiber assembly; and a passive element (capacitor) which includes a high-k layer which is composed of the insulating material, and an electroconductive part stacked on the high-k layer.

A power storage material is made by using a fiber material of cellulose molecules obtained from wood, plant fibers (pulp), and the like, and capable of storing electric power of direct current and alternating current, and an ultra power storage body has the power storage material. A power storage material includes a fiber mainly including a fiber derived from at least any one of wood, plant fibers (pulp), animals, algae, microorganisms, and microbial products, and having a large number of recesses and protrusions on a surface. The fiber is preferably crystallized/amorphous fibers, is preferably an amorphous fiber having an atomic vacancy, and preferably has a specific surface area of 10 m.sup.2/g or more. Preferably, the large number of recesses and protrusions have a diameter of 1 nm to 500 nm. Preferably, the electric resistance is 100 M or more, and the electric capacity is 5 mF/cm.sup.2 or more.

A power storage material is made by using a fiber material of cellulose molecules obtained from wood, plant fibers (pulp), and the like, and capable of storing electric power of direct current and alternating current, and an ultra power storage body has the power storage material. A power storage material includes a fiber mainly including a fiber derived from at least any one of wood, plant fibers (pulp), animals, algae, microorganisms, and microbial products, and having a large number of recesses and protrusions on a surface. The fiber is preferably crystallized/amorphous fibers, is preferably an amorphous fiber having an atomic vacancy, and preferably has a specific surface area of 10 m.sup.2/g or more. Preferably, the large number of recesses and protrusions have a diameter of 1 nm to 500 nm. Preferably, the electric resistance is 100 M or more, and the electric capacity is 5 mF/cm.sup.2 or more.

The present disclosure provides capacitors for storing electrical energy. The capacitors can comprise, at least in part, bast fiber, bast powder, hurd fiber, hurd powder, or a derivative thereof. In some instances, a dielectric of a capacitor can be formed of bast fiber, bast powder, hurd fiber, hurd powder, or a derivative thereof. In other instances, one or both electrodes of the capacitor can be formed of bast fiber, bast powder, hurd fiber, hurd powder, or a derivative thereof. The resulting capacitors can be configured to have various power densities and various energy densities over various minimum numbers of charge/discharge cycles at a certain specified range of operating temperatures.

The present disclosure provides capacitors for storing electrical energy. The capacitors can comprise, at least in part, bast fiber, bast powder, hurd fiber, hurd powder, or a derivative thereof. In some instances, a dielectric of a capacitor can be formed of bast fiber, bast powder, hurd fiber, hurd powder, or a derivative thereof. In other instances, one or both electrodes of the capacitor can be formed of bast fiber, bast powder, hurd fiber, hurd powder, or a derivative thereof. The resulting capacitors can be configured to have various power densities and various energy densities over various minimum numbers of charge/discharge cycles at a certain specified range of operating temperatures.

The present disclosure relates to a condenser core configured for surrounding an electrical conductor. The condenser core includes an insulation material and a plurality of electrically conducting capacitive layers for modifying electrical fields formed by a current flowing in the electrical conductor. At least one of the electrically conducting capacitive layers includes a first foil and a second foil. Each of the first and second foils of an outermost capacitive layer is connected with a grounding arrangement for grounding the foils.

The present disclosure provides capacitors for storing electrical energy. The capacitors can comprise, at least in part, bast fiber, bast powder, hurd fiber, hurd powder, or a derivative thereof. In some instances, a dielectric of a capacitor can be formed of bast fiber, bast powder, hurd fiber, hurd powder, or a derivative thereof. In other instances, one or both electrodes of the capacitor can be formed of bast fiber, bast powder, hurd fiber, hurd powder, or a derivative thereof. The resulting capacitors can be configured to have various power densities and various energy densities over various minimum numbers of charge/discharge cycles at a certain specified range of operating temperatures.

The present disclosure provides capacitors for storing electrical energy. The capacitors can comprise, at least in part, bast fiber, bast powder, hurd fiber, hurd powder, or a derivative thereof. In some instances, a dielectric of a capacitor can be formed of bast fiber, bast powder, hurd fiber, hurd powder, or a derivative thereof. In other instances, one or both electrodes of the capacitor can be formed of bast fiber, bast powder, hurd fiber, hurd powder, or a derivative thereof. The resulting capacitors can be configured to have various power densities and various energy densities over various minimum numbers of charge/discharge cycles at a certain specified range of operating temperatures.