In an embodiment, the present disclosure pertains to a metal oxide-coated nanofiber yarn. In some embodiments, the metal oxide-coated nanofiber yarn includes a plurality of twisted carbon nanofibers. In some embodiments, each twisted carbon nanofiber includes a porous hollow fiber. In some embodiments, each twisted carbon nanofiber includes metal oxide nanoparticles coated on a surface thereof. In some embodiments, an outer surface of each twisted carbon nanofiber, an inner surface of each twisted carbon nanofiber, and holes or channels of a main fiber skeleton of the plurality of twisted carbon nanofibers with the possibility of transferring a metal ion are covered by the metal oxide nanoparticles. In a further embodiment, the present disclosure pertains to methods of making the metal oxide-coated nanofiber yarn. In an additional embodiment, the present disclosure pertains to a structural supercapacitor utilizing the metal oxide-coated nanofiber yarn.

In an embodiment, the present disclosure pertains to a metal oxide-coated nanofiber yarn. In some embodiments, the metal oxide-coated nanofiber yarn includes a plurality of twisted carbon nanofibers. In some embodiments, each twisted carbon nanofiber includes a porous hollow fiber. In some embodiments, each twisted carbon nanofiber includes metal oxide nanoparticles coated on a surface thereof. In some embodiments, an outer surface of each twisted carbon nanofiber, an inner surface of each twisted carbon nanofiber, and holes or channels of a main fiber skeleton of the plurality of twisted carbon nanofibers with the possibility of transferring a metal ion are covered by the metal oxide nanoparticles. In a further embodiment, the present disclosure pertains to methods of making the metal oxide-coated nanofiber yarn. In an additional embodiment, the present disclosure pertains to a structural supercapacitor utilizing the metal oxide-coated nanofiber yarn.

This invention relates to particulate electroactive materials consisting of a plurality of composite particles, wherein the composite particles comprise: (a) a porous conductive particle framework including micropores and/or mesopores having a total volume of at least 0.4 to 2.2 cm.sup.3/g; (b) an electroactive material disposed within the porous conductive particle framework; and (c) a lithium-ion permeable filler penetrating the pores of the porous conductive particle framework and disposed intermediate the nanoscale silicon domains and the exterior of the composite particles.

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 MΩ or more, and the electric capacity is 5 mF/cm.sup.2 or more

The positive active material for an energy storage device according to one aspect of the present invention has an olivine-type crystal structure, has a surface at least partially coated with carbon, and satisfies either (A) or (B) below. (A) a pore volume in a range of a pore size of 60 nm or more and 200 nm or less determined by a BJH method from a desorption isotherm using a nitrogen gas adsorption method is 0.05 cm.sup.3/g or more and 0.25 cm.sup.3/g or less, and a pore specific surface area in a range of a pore size of 10 nm or more and 200 nm or less using a nitrogen gas adsorption method is 5 m.sup.2/g or more; (B) a full width at half maximum ratio (200)/(131) of a peak corresponding to a (200) plane to a peak corresponding to a (131) plane by a powder X-ray diffraction method using a CuKα ray in a charged state is 1.10 or less.

Electrochemical device 200 disclosed includes positive electrode 10 and negative electrode 20. Positive electrode 10 includes a positive electrode material layer. The positive electrode material layer contains particles of an active material and a conductive agent. The cohesive force between the particles of the active material and the conductive agent is greater than the cohesive force between the conductive agent.

The disclosed technology generally relates to energy storage devices, and more particularly to energy storage devices comprising frustules. According to an aspect, a supercapacitor comprises a pair of electrodes and an electrolyte, wherein at least one of the electrodes comprises a plurality of frustules having formed thereon a surface active material. The surface active material can include nanostructures. The surface active material can include one or more of a zinc oxide, a manganese oxide and a carbon nanotube.

The disclosed technology generally relates to energy storage devices, and more particularly to energy storage devices comprising frustules. According to an aspect, a supercapacitor comprises a pair of electrodes and an electrolyte, wherein at least one of the electrodes comprises a plurality of frustules having formed thereon a surface active material. The surface active material can include nanostructures. The surface active material can include one or more of a zinc oxide, a manganese oxide and a carbon nanotube.

Provided is a conductive carbon mixture which is to be used together with an electrode active material in manufacturing an electrode of an electricity storage device and enables the manufacture of the electricity storage device having a good cycle life. The conductive carbon mixture for manufacturing an electrode of an electricity storage device comprises an oxidized carbon having electrical conductivity and a different conductive carbon which is different from the oxidized carbon, wherein the oxidized carbon covers the surface of the different conductive carbon. The conductive carbon mixture is characterized in that the ratio of the peak intensity of the 2D band to the peak intensity of the D band in a Raman spectrum of the conductive carbon mixture is 55% or less relative to the ratio of the peak intensity of the 2D band to the peak intensity of the D band in a Raman spectrum of the different conductive carbon. This conductive carbon mixture covers the surface of the electrode active material in a particularly good manner and thus prolongs the cycle life of the electricity storage device.

A supercapacitor is provided. The supercapacitor includes an elastic fiber, an internal electrode, a first electrolyte layer, and an external electrode. The internal electrode, the first electrolyte layer, and the external electrode are sequentially wrapped on an outer surface of the elastic fiber. The internal electrode includes a first carbon nanotube film and a NiO@MnO.sub.x composite structure, and the external electrode includes a second carbon nanotube film and a Fe.sub.2O.sub.3 layer.