Nippon Electric Glass Co., Ltd.

Junichi Ikejiri

Hideo Yamauchi

Fumio Sato

Tsuyoshi Honma

Takayuki Komatsu

Provided is a thin beta-alumina-based solid electrolyte sheet having a high ion conduction value. The solid electrolyte sheet containing β-alumina and/or β″-alumina and having a thickness of 1 mm or less and a voidage of 20% or less.

Solid electrolyte sheet, method for manufacturing same, and sodium ion all-solid-state secondary cell

Provided are a sodium ion-conductive crystal-containing solid electrolyte sheet capable of giving excellent battery characteristics even when reduced in thickness, and an all-solid-state battery using the same. The solid electrolyte sheet contains at least one type of sodium ion-conductive crystal selected from &#x3b2;&#x2033;-alumina and NASICON crystal and has a thickness of 500 &#x3bc;m or less and a flatness of 200 &#x3bc;m or less.

Solid electrolyte sheet, method for producing same and all-solid-state secondary battery

Provided is an all-solid-state sodium ion secondary battery in which a current collector is difficult to peel from an electrode layer and which can suppress the decreases in discharge capacity and discharge voltage. An all-solid-state sodium ion secondary batteryaccording to the present invention includes: a solid electrolyte layermade of a sodium ion-conductive oxide; a positive electrode layerformed on a first principal surfaceof the solid electrolyte layer; a negative electrode layerformed on a second principal surfaceof the solid electrolyte layer; and a current collector layerformed on a principal surface of at least one of the positive electrode layerand the negative electrode layer, wherein the current collector layeris made of at least one metallic material selected from the group consisting of aluminum, titanium, silver, copper, stainless steel, and alloys thereof, and the current collector layerhas a thickness of not less than 10 nm and not more than 10 &#x3bc;m.

All-solid-state sodium ion secondary battery

Provided is a thin beta-alumina-based solid electrolyte sheet having a high ion conduction value. The solid electrolyte sheet containing &#x3b2;-alumina and/or &#x3b2;&#x2033;-alumina and having a thickness of 1 mm or less and a voidage of 20% or less.

Provided are a positive electrode active material for a sodium ion secondary battery excellent in quick charge-discharge characteristics by preventing fusion between particles of powder during firing, and a method of producing the same. A positive electrode active material for a sodium ion secondary battery of the present invention includes inorganic powder that contains at least one kind of transition metal element selected from the group consisting of Cr, Fe, Mn, Co, and Ni, Na, P, and O, and has a BET specific surface area of from 3 m/g to 50 m/g.

Positive electrode active material for sodium ion secondary batteries and method for producing same

Provided are a cathode active material for a sodium ion secondary battery that is excellent in alkali ion diffusivity, structural stability, and cycle performance, and a synthesis method therefor. The cathode active material for a sodium ion secondary battery includes a melt-solidified body or oxide glass represented by the general formula NaMPO(where M represents at least one or more kinds of transition metal elements selected from Cr, Fe, Mn, Co, and Ni, x satisfies a relationship of 1.20&#x2264;x&#x2264;2.10, and y satisfies a relationship of 0.95&#x2264;y&#x2264;1.60).

Cathode active material for sodium secondary battery and method for manufacturing the cathode active material for sodium secondary battery

A composite material as an electrode for a sodium ion secondary battery includes an active material crystal, a sodium-ion conductive crystal, and an amorphous phase. The active material crystal may contain Na, M (where M represents at least one kind of transition metal element selected from Cr, Fe, Mn, Co, and Ni), P, and O.

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Otsu, Japan

Junichi Ikejiri