Solid electrolyte and secondary battery

Patent metadata

Field	Value
Publication number	US-9812733-B2
Application number	US-201514612372-A
Country	US
Kind code	B2
Filing date	Feb 3, 2015
Priority date	Feb 28, 2014
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

Provided is a sulfide-based solid electrolyte, including: a Na element; a Ge element; a P element; and a S element, wherein an atomic percentage (at. %) of each of the Na element, the Ge element, the P element, and the S element is as follows when a total of the respective elements is 100 at. %,
Na: from 38.8 at. % to 48.4 at. % Ge: from 0.5 at. % to 8.9 at. % P: from 3.9 at. % to 7.9 at. % S: from 43.6 at. % to 48.6 at. %.

First claim

What is claimed is:

1. A sodium-sulfur based solid electrolyte, comprising:
a Na element;
a Ge element;
a P element; and
a S element,
wherein the sodium-sulfur based solid electrolyte has a Na ion conductivity of 1.5×10 −4 S/cm or higher at 25° C., and
an atomic percentage (at. %) of each of the Na element, the Ge element, the P element, and the S element is as follows when a total of the respective elements in the sodium-sulfur based solid electrolyte is 100 at. %,
Na: from 38.8 at. % to 48.4 at. %
Ge: from 0.5 at. % to 8.9 at. %
P: from 3.9 at. % to 7.9 at. %
S: from 43.6 at. % to 48.6 at. %.

2. The sodium-sulfur based solid electrolyte according to claim 1 ,
wherein the atomic percentage (at. %) of each of the Na element, the Ge element, the P element, and the S element is as follows,
Na: from 40.4 at. % to 44.3 at. %
Ge: from 3.3 at. % to 6.7 at. %
P: from 5.5 at. % to 6.7 at. %
S: from 45.6 at. % to 47.4 at. %.

3. The sodium-sulfur based solid electrolyte according to claim 1 ,
wherein the sodium-sulfur based solid electrolyte has peaks at 2θ positions of 29.30°±1.00° and 27.20°±1.00° when measured by X-ray diffraction measurement using a Cu-Kα ray, and
wherein when a diffraction intensity of the peak at the 2θ position of 29.30°±1.00° is defined as IA and a diffraction intensity of the peak at the 2θ position of 27.20°±1.00° is defined as IB, a value IB/IA is 0.60 or greater.

4. The sodium-sulfur based solid electrolyte according to claim 1 ,
wherein the sodium-sulfur based solid electrolyte has a Na ion conductivity of 2.0×10−4 S/cm or higher at 25° C.

5. The sodium-sulfur based solid electrolyte according to claim 1 , wherein starting materials for the sodium-sulfur based solid electrolyte include Na 2 S.

6. A sodium secondary battery, comprising:
a positive electrode;
a negative electrode; and
a solid electrolyte,
wherein the solid electrolyte in the sodium secondary battery comprises:
a Na element;
a Ge element;
a P element; and
a S element,
wherein an atomic percentage (at. %) of each of the Na element, the Ge element, the P element, and the S element is as follows when a total of the respective elements is 100 at. %,
Na: from 38.8 at. % to 48.4 at. %
Ge: from 0.5 at. % to 8.9 at. %
P: from 3.9 at. % to 7.9 at. %
S: from 43.6 at. % to 48.6 at. %.

7. The sodium secondary battery according to claim 6 ,
wherein the positive electrode of the sodium secondary battery includes one or more sodium metallates.

8. The sodium secondary battery according to claim 6 , wherein the positive electrode of the sodium secondary battery includes one or more sodium metallates selected from a group consisting of sodium cobaltate, sodium manganate, and sodium nickelate.

9. The sodium secondary battery according to claim 6 , wherein the negative electrode of the sodium secondary battery includes an active material selected from a group consisting of a sodium metal, a sodium alloy, and a sodium ion.

Assignees

• Takeuchi Shigeo
• Yuzurihara Hajime
• Kanno Ryoji
• Ricoh Co Ltd
• Tokyo Inst Tech

Inventors

• Takeuchi Shigeo
• Yuzurihara Hajime
• Kanno Ryoji

Classifications

• H01M10/3918

  characterised by the electrolyte · CPC title

• H01B1/10

  sulfides · CPC title

• H01M2300/0068

  inorganic · CPC title

• H01M10/054

  Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium · CPC title

• H01M2300/002

  Inorganic electrolyte · CPC title