Positive electrode for nonaqueous electrolyte secondary batteries, and nonaqueous electrolyte secondary battery

Patent metadata

Field	Value
Publication number	US-11569493-B2
Application number	US-201816631049-A
Country	US
Kind code	B2
Filing date	Sep 28, 2018
Priority date	Oct 31, 2017
Publication date	Jan 31, 2023
Grant date	Jan 31, 2023

Abstract

A positive electrode including a positive electrode current collector, an intermediate layer disposed on the positive electrode current collector and including a conductive agent and inorganic particles, and a positive electrode mixture layer disposed on the intermediate layer and including a positive electrode active material and a hydrogen phosphate salt represented by the general formula MaHbPO4 (wherein a satisfies 1≤a≤2, b satisfies 1≤b≤2, and M includes at least one element selected from alkali metals and alkaline earth metals), the positive electrode satisfying 0.5≤X≤3.0, 1.0≤Y≤7.0, and 0.07≤X/Y≤3.0 wherein X is the mass ratio (mass %) of the hydrogen phosphate salt relative to the total mass of the positive electrode active material and Y is the mass ratio (mass %) of the conductive agent relative to the total mass of the intermediate layer.

First claim

The invention claimed is:

1. A positive electrode for nonaqueous electrolyte secondary batteries comprising:
a positive electrode current collector;
an intermediate layer disposed on the positive electrode current collector and including a conductive agent and inorganic particles; and
a positive electrode mixture layer disposed on the intermediate layer and including a positive electrode active material and a hydrogen phosphate salt represented by the general formula M a H b PO 4 , wherein a satisfies 1≤a≤2, b satisfies 1≤b≤2, and M includes at least one element selected from alkali metals and alkaline earth metals,
the positive electrode satisfying 0.5≤X≤3.0, 1.0≤Y≤7.0, and 0.07≤X/Y≤3.0 wherein X is the mass ratio, in mass %, of the hydrogen phosphate salt relative to the total mass of the positive electrode active material and Y is the mass ratio, in mass %, of the conductive agent relative to the total mass of the intermediate layer,
wherein the content of the hydrogen phosphate salt present in a region extending from a surface of the positive electrode mixture layer adjacent to the intermediate layer to ½ thickness of the positive electrode mixture layer is not less than 55 mass % of the total mass of the hydrogen phosphate salt in the positive electrode mixture layer.

2. The positive electrode for nonaqueous electrolyte secondary batteries according to claim 1 , wherein the positive electrode active material comprises a lithium transition metal oxide represented by the general formula Li 1+x Ni a M 1-a O 2+b (wherein x, a and b satisfy −0.2<x≤0.2, 0.5≤a≤1, and −0.1≤b≤0.1, and M includes at least one element selected from Co, Mn and Al.

3. The positive electrode for nonaqueous electrolyte secondary batteries according to claim 1 , wherein the hydrogen phosphate salt comprises at least one of Li 2 HPO 4 and LiH 2 PO 4 .

4. A nonaqueous electrolyte secondary battery comprising the positive electrode for nonaqueous electrolyte secondary batteries described in claim 1 .

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Ko Takashi
• Baba Yasunori
• Yanagida Katsunori
• Hirano Nobuhiro
• Niina Fumiharu

Classifications

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M2004/027

  Negative electrodes · CPC title

• H01M4/131

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

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01M4/136 Primary

  Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title