Secondary battery positive electrode and secondary battery

Patent metadata

Field	Value
Publication number	US-11437613-B2
Application number	US-202016733615-A
Country	US
Kind code	B2
Filing date	Jan 3, 2020
Priority date	Jul 21, 2017
Publication date	Sep 6, 2022
Grant date	Sep 6, 2022

Abstract

This secondary battery positive electrode includes: a positive electrode current collector; an intermediate layer provided on the positive electrode current collector; and a positive electrode mixture layer provided on the intermediate layer and including a positive electrode active material, wherein the intermediate layer includes a conductive material, a metal phosphate, and an inorganic compound which is not a metal phosphate and has a lower oxidizing power than the positive electrode active material.

First claim

The invention claimed is:

1. A secondary battery, comprising:
a positive electrode comprising:
a positive electrode current collector;
an intermediate layer disposed on the positive electrode current collector; and
a positive electrode mixture layer disposed on the intermediate layer and including a positive electrode active material,
wherein the intermediate layer includes: a conductive agent, a metal phosphorus oxide, and an inorganic compound other than the metal phosphorus oxide, the inorganic compound having a lower oxidative power than that of the positive electrode active material;

a negative electrode;
a separator disposed between the positive electrode mixture layer of the positive electrode and the negative electrode; and
an electrolyte,
wherein the metal phosphorus oxide and the inorganic compound are present in a part of the positive electrode mixture layer extending from the interface between the positive electrode mixture layer and the intermediate layer to a level of about ⅕ of the thickness of the positive electrode mixture layer.

2. The secondary battery according to claim 1 , wherein at least one of the metal phosphorus oxide and the inorganic compound has a Mohs hardness of 7 or less.

3. The secondary battery according to claim 1 , wherein a content of the metal phosphorus oxide is 80 mass % or more and 99.5 mass % or less based on the total amount of the metal phosphorus oxide and the inorganic compound.

4. The secondary battery according to claim 3 , wherein the metal phosphorus oxide has a Mohs hardness of 7 or less.

5. The secondary battery according to claim 1 , wherein a ratio between an average particle diameter of the metal phosphorus oxide and an average particle diameter of the inorganic compound is 0.5:1 to 2:1.

6. The secondary battery according to claim 1 , wherein an average particle diameter of the metal phosphorus oxide is 0.05 μm or more and 5 μm or less, and an average particle diameter of the inorganic compound is 0.1 μm or more and 5 μm or less.

7. The secondary battery according to claim 1 , wherein the metal phosphorus oxide includes at least one of the group consisting of Li 3 PO 4 , LiPON, Li 2 HPO 4 , LiH 2 PO 4 , Na 3 PO 4 , Na 2 HPO 4 , NaH 2 PO 4 , Zr 3 (PO 4 ) 4 , Zr(HPO 4 ) 2 , HZr 2 (PO 4 ) 3 , K 3 PO 4 , K 2 HPO 4 , KH 2 PO 4 , Ca 3 (PO 4 ) 2 , CaHPO 4 , Mg 3 (PO 4 ) 2 , MgHPO 4 , LiCl—Li 5 P 3 O 10 , LiCl—Li 7 P 5 O 16 , LiCl—LiPO 3 , LiCl—Li 2 O—P 2 O 5 , Li 2 O—P 2 O 5 , AgI—AgPO 3 , CuI—CuPO 3 , PbF 2 —MnF 2 —Al(PO 4 ) 3 , and AgI—Ag 2 O—P 2 O 5 .

8. The secondary battery according to claim 7 , wherein the metal phosphorus oxide includes at least one of the group consisting of Li 3 PO 4 , Ca 3 (PO 4 ) 2 , and K 3 PO 4 .

9. The secondary battery according to claim 1 , wherein the inorganic compound includes at least one of the group consisting of aluminum oxide, titanium dioxide, silicon dioxide, and manganese oxide.

10. The secondary battery according to claim 1 , wherein in a part of the positive electrode active material layer extending from the surface on the separator side to a level of about ⅘ of the thickness of the positive electrode active material layer in the thickness direction of the positive electrode active material layer, the total amount of the metal phosphorus oxide and the inorganic compound other than the metal phosphorus oxide included therein is less than 0.5 mass %.

11. The secondary battery according to claim 1 , wherein the intermediate layer is free of at least one of the group consisting of LiMnPO 4 , Li 2 MPO 4 F wherein M is Co or Ni, and ferrous metal phosphorus oxides.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Takahashi Takahiro
• Takezawa Hideharu
• Shiozaki Tomoki

Classifications

• H01M4/667 Primary

  in the form of layers, e.g. coatings · CPC title

• H01M4/13

  Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/131

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title