Provided are a composite that can be suitably used as an electrolyte for polymer-based solid-state batteries and is excellent in oxidation resistance and flame retardancy, and various electrochemical devices using such a composite. The composite contains a fluorine-containing copolymer that comprises a tetrafluoroethylene (TFE) unit and a vinylidene fluoride (VdF) unit, and an alkali metal salt, wherein the total content of the TFE unit and the VdF unit in the fluorine-containing copolymer is 1 to 99 mol %, and the composite has a volatile content of 0.1 mass % or less with respect to the entire composite.

A solid-state battery that includes a positive electrode layer; a negative electrode layer; and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer, wherein at least one electrode layer of the positive electrode layer and the negative electrode layer contains a conductive agent composed of a metal material, and the conductive agent is coated with a coating material having a melting point higher than that of the conductive agent.

An oxide-based solid electrolyte with a high lithium ion conductance is provided. A lithium ion-conducting garnet type oxide includes Li, La, Ga, Zr, a halogen element, and oxygen. A lithium ion conductivity at room temperature is not lower than 1.0×10.sup.−3 S/cm. A proportion of Ga with respect to 1 mole of the oxide may be not larger than 0.5 moles.

The halogen element may be at least one type selected from the group consisting of Cl, Br, and I, and a proportion of Li with respect to 1 mole of the oxide may be not smaller than 6.1 moles and smaller than 6.5 moles.

Provided are a solid electrolyte composition containing an inorganic solid electrolyte having a conductivity of an ion of a metal belonging to Group I or II of the periodic table and a binder having a specific hydrocarbon polymer segment and a specific segment, a solid electrolyte-containing sheet in which the same solid electrolyte composition is used and a manufacturing method therefor, an all-solid state secondary battery and a manufacturing method therefor, a polymer having a specific hydrocarbon polymer segment and a specific segment, and a non-aqueous solvent dispersion thereof.

An objective of the present invention is to provide an all-solid-state battery with a high discharge capacity in which lithium vanadium phosphate is used as a positive electrode active material layer and a negative electrode active material layer. According to the present invention, the positive electrode active material layer and the negative electrode active material layer of the all-solid-state battery having an all-solid-state electrolyte between a pair of electrodes contain the lithium vanadium phosphate, the lithium vanadium phosphate contains a polyphosphate compound containing Li and V, and the lithium vanadium phosphate contains Li.sub.3V.sub.2(PO.sub.4).sub.3 as a main phase and contains 1.0% by weight or more and 15.0% by weight or less of Li.sub.3PO.sub.4 relative to Li.sub.3V.sub.2(PO.sub.4).sub.3, whereby a high discharge capacity can be provided.

Composite nanoparticle compositions and associated nanoparticle assemblies are described herein which, in some embodiments, exhibit enhancements to one or more thermoelectric properties including increases in electrical conductivity and/or Seebeck coefficient and/or decreases in thermal conductivity. In one aspect, a composite nanoparticle composition comprises a semiconductor nanoparticle including a front face and a back face and sidewalls extending between the front and back faces. Metallic nanoparticles are bonded to at least one of the sidewalls establishing a metal-semiconductor junction.

Provided is a battery having further improved charging/discharging efficiency. The battery comprises a positive electrode, a negative electrode, and an electrolyte layer provided between the positive electrode and the negative electrode. The electrolyte layer includes a first electrolyte layer and a second electrolyte layer. The second electrolyte layer is provided between the first electrolyte layer and the negative electrode. The first electrolyte layer includes a first solid electrolyte material. The second electrolyte layer includes a second solid electrolyte material that is a material different from the first solid electrolyte material. The first solid electrolyte material includes Li, M, and X and does not include sulfur. M includes at least one selected from the group consisting of metalloid elements and metal elements other than Li. X is at least one selected from the group consisting of Cl, Br, and I. The reduction potential with regard to lithium of the second solid electrolyte material is lower than the reduction potential with regard to lithium of the first solid electrolyte material.

Provided is a method for producing a solid electrolyte having peaks at 2θ=20.2°±0.5° and 23.6°±0.5° in X-ray diffractometry using a CuKα ray and containing a lithium element, a phosphorus element, a sulfur element, and a halogen element, the method including using raw materials containing yellow phosphorus and a compound containing a lithium element, a sulfur element, and a halogen element.

A sulfide solid electrolyte to be used in a lithium-ion secondary battery, including: a crystal phase; and an anion existing in a crystal structure of the crystal phase, in which the crystal phase includes an argyrodite crystal containing Li, P, S, and Ha; Ha is at least one element selected from the group consisting of F, Cl, Br, and I; the anion includes an oxide anion having a Q0 structure having an M-O bond that is a bond of M and O; and M is at least one element selected from the group consisting of metal elements and semimetal elements belonging to Groups 2 to 14 of a periodic table.

The solid electrolyte material of the present disclosure consists of Li, M1, M2, and X, wherein M1 is at least two selected from the group consisting of Ca, Mg, and Zn; M2 is at least one selected from the group consisting of Y, Gd, and Sm; and X is at least one selected from the group consisting of F, Cl, Br, and I.