All-solid lithium secondary battery

Patent metadata

Field	Value
Publication number	US-9780407-B2
Application number	US-201514699711-A
Country	US
Kind code	B2
Filing date	Apr 29, 2015
Priority date	Aug 29, 2013
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

An exemplary all-solid lithium secondary battery includes a positive electrode including a positive-electrode active substance layer, a negative electrode, and a solid electrolyte layer interposed between the positive electrode and the negative electrode. The positive-electrode active substance layer is composed of lithium cobaltate, and has an α-NaFeO 2 type crystal structure. The positive-electrode active substance layer has a (018) plane oriented in a normal direction of a principal face of the positive-electrode active substance layer. The solid electrolyte layer is composed of lithium lanthanum titanate and has a tetragonal perovskite-type crystal structure. The solid electrolyte layer has a (110) plane or a (102) plane oriented in a normal direction of a principal face of the solid electrolyte layer.

First claim

What is claimed is:

1. An all-solid lithium secondary battery comprising:
a positive electrode including a positive-electrode active substance layer;
a negative electrode including a negative-electrode active substance layer, the negative-electrode active substance layer allowing lithium ions to be inserted and allowing inserted lithium ions to be released; and
a solid electrolyte layer interposed between the positive electrode and the negative electrode, wherein,
the positive-electrode active substance layer comprises lithium cobaltate, and has an α-NaFeO 2 type crystal structure;
the positive-electrode active substance layer has a (018) plane oriented in a normal direction of a principal face of the positive-electrode active substance layer;
the solid electrolyte layer comprises lithium lanthanum titanate and has a tetragonal perovskite-type crystal structure; and
the solid electrolyte layer has a (110) plane or a (102) plane oriented in a normal direction of a principal face of the solid electrolyte layer.

2. The all-solid lithium secondary battery of claim 1 , wherein the positive-electrode active substance layer and the solid electrolyte layer are epitaxial films.

3. The all-solid lithium secondary battery of claim 2 , wherein the solid electrolyte layer is an epitaxial film that matches a crystal orientation of the positive-electrode active substance layer.

4. The all-solid lithium secondary battery of claim 1 , wherein a [−4-81] direction in the positive-electrode active substance layer is parallel to a [001] direction or a [010] direction in the solid electrolyte layer, and a [100] direction in the positive-electrode active substance layer is parallel to a [1-10] direction or a [−201] direction in the solid electrolyte layer.

5. The all-solid lithium secondary battery of claim 1 , wherein, in an X-ray diffraction pattern of the positive-electrode active substance layer, a ratio (I(018)/I(003)) between a peak intensity I(018) of the (018) plane and a peak intensity I(003) of the (003) plane satisfies the relationship I(018)/I(003)>20.

6. An all-solid lithium secondary battery comprising:
a positive electrode including a positive-electrode active substance layer;
a negative electrode including a negative-electrode active substance layer, the negative-electrode active substance layer allowing lithium ions to be inserted and allowing inserted lithium ions to be released;
a solid electrolyte layer interposed between the positive electrode and the negative electrode, wherein,
the positive-electrode active substance layer comprises lithium cobaltate, and has an α-NaFeO 2 type crystal structure;
given an x axis and a y axis which are defined as two axes that are parallel to a principal face of the positive-electrode active substance layer, and a z axis which is defined as an axis that is perpendicular to the principal face,
the positive-electrode active substance layer is composed only of first regions having a (110) plane oriented in the z axis direction and second regions having a (018) plane oriented in the z axis direction, the first regions and second regions being mixedly present in an xy plane of the positive-electrode active substance layer;
the solid electrolyte layer comprises lithium lanthanum titanate and has a tetragonal perovskite-type crystal structure; and
the solid electrolyte layer has a (110) plane or a (102) plane in a normal direction of a principal face of the solid electrolyte layer.

7. The all-solid lithium secondary battery of claim 6 , wherein the positive-electrode active substance layer and the solid electrolyte layer are epitaxial films.

8. The all-solid lithium secondary battery of claim 7 , wherein the solid electrolyte layer is an epitaxial film that matches a crystal orientation of the positive-electrode active substance layer.

9. The all-solid lithium secondary battery of claim 6 , wherein, in an X-ray diffraction pattern of the positive-electrode active substance layer, a ratio (I(110)/I(018)) between a peak intensity I(110) of the (110) plane and a peak intensity I(018) of the (018) plane is 0.3 or 1.0.

10. The all-solid lithium secondary battery of claim 2 , wherein the positive-electrode active substance layer is formed on a current collector which is a strontium titanate substrate, the strontium titanate substrate being doped with a dopant and electrically conductive.

11. The all-solid lithium secondary battery of claim 7 , wherein the positive-electrode active substance layer is formed on a current collector which is a strontium titanate substrate, the strontium titanate substrate being doped with a dopant and electrically conductive.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Asano Tetsuya
• Komori Tomoyuki
• Fujii Eiji

Classifications

• H01M10/052

  Li-accumulators · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M4/664

  Ceramic materials · CPC title

• H01M10/0562 Primary

  Solid materials · CPC title

• H01M4/66

  Selection of materials · CPC title