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

Patent metadata

Field	Value
Publication number	US-2020075955-A1
Application number	US-201716344339-A
Country	US
Kind code	A1
Filing date	Oct 31, 2017
Priority date	Nov 4, 2016
Publication date	Mar 5, 2020
Grant date	—

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.
Li a Fe 1-x M x PO 4   [Chemical Formula 1]
(In Chemical Formula 1, 0.90≤a≤1.8, 0≤x≤0.7, and M is Mg, Co, Ni, or a combination thereof)

First claim

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 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:
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 an average particle diameter (D50) of the compound of Chemical Formula 1 is 0.2 μm to 1 μm.

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

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

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

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

7 . 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.

8 . 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

• H01M10/0525

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

• H01M2004/028

  Positive electrodes · CPC title

• H01M4/622

  being polymers · CPC title

• H01M4/58

  of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates · CPC title