Positive electrode for lithium secondary battery and lithium secondary battery comprising same

Patent metadata

Field	Value
Publication number	US-11296323-B2
Application number	US-201716344339-A
Country	US
Kind code	B2
Filing date	Oct 31, 2017
Priority date	Nov 4, 2016
Publication date	Apr 5, 2022
Grant date	Apr 5, 2022

Abstract

The present invention relates to a positive electrode for a lithium secondary battery and a lithium secondary battery comprising the same, wherein the positive electrode comprises: a current collector; an active material layer formed on the current collector and comprising a compound capable of intercalating and deintercalating lithium; and a coating layer formed on the active material layer and comprising an aqueous binder and a compound of Chemical Formula 1 having an average particle diameter (D50) of 2 μm or less.LiaFe1-xMxPO4  [Chemical Formula 1](In Chemical Formula 1, 0.90≤a≤1.8, 0≤x≤0.7, andM is Mg, Co, Ni, or a combination thereof)

First claim

The invention claimed is:

1. A positive electrode for a lithium secondary battery, comprising:
a current collector;
an active material layer formed on the current collector and comprising a compound capable of intercalating and deintercalating lithium; and
a coating layer separately formed on the active material layer and comprising an aqueous binder and a compound of Chemical Formula 1 having an average particle diameter (D50, indicating a diameter of a particle where a cumulative volume is about 50 volume % in a particle distribution) of 0.2 μm to 1 μm;
the aqueous binder comprises a styrene-butadiene rubber, an acrylate-based compound, an imide-based compound, a nitrile-based compound, an acetate-based compound, a cellulose-based compound, or a cyano-based compound:
Li a Fe 1-x M x PO 4   [Chemical Formula 1]

wherein, in Chemical Formula 1, 0.90≤a≤1.8, 0≤x≤0.7, and
M is Mg, Co, Ni, or a combination thereof.

2. The positive electrode for a lithium secondary battery of claim 1 , wherein a thickness of the coating layer is 1 μm to 13 μm.

3. The positive electrode for a lithium secondary battery of claim 1 , wherein the aqueous binder is an aqueous binder having oxidation resistance.

4. The positive electrode for a lithium secondary battery of claim 1 , wherein the coating layer further comprises a thickener.

5. The positive electrode for a lithium secondary battery of claim 1 , wherein a ratio of the thickness of the active material layer to that of the coating layer is 30:1 to 10:1.

6. The positive electrode for a lithium secondary battery of claim 1 , wherein a mixing ratio of the compound of Chemical Formula 1 and the aqueous binder is 24:1 weight ratio to 50:1 weight ratio.

7. A lithium secondary battery, comprising
the positive electrode of claim 1 ;
a negative electrode comprising a negative active material, and
an electrolyte.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Jeon Bokkyu
• Nam Junghyun
• Seok Hoon
• Yoo Heeeun
• Yoon Yeonhee
• JIN Mokyun

Classifications

• H01M10/4235

  Safety or regulating additives or arrangements in electrodes, separators or electrolyte (H01M10/4242 takes precedence) · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M10/0525

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

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title