Positive electrode for rechargeable lithium battery and method of preparing same, negative electrode for rechargeable lithium battery and method of preparing same

Patent metadata

Field	Value
Publication number	US-2016049637-A1
Application number	US-201514742756-A
Country	US
Kind code	A1
Filing date	Jun 18, 2015
Priority date	Aug 13, 2014
Publication date	Feb 18, 2016
Grant date	—

Abstract

Provided are a positive electrode and a negative electrode for a rechargeable lithium battery. For example, the positive electrode includes a current collector; and a positive active material layer on the current collector. The positive active material layer has a first region adjacent to the current collector and a second region separated from the current collector by the first region, each of the first region and second region having a thickness equal to ½ of a total thickness of the positive active material layer. The first region has a first average pore size, and the second region has a second average pore size. A ratio of the second average pore size to the first average pore size is greater than about 0.5 and less than or equal to about 1.0. The positive electrode has an active mass density of about 2.3 g/cc to about 4.5 g/cc.

First claim

What is claimed is:

1 . A positive electrode for a rechargeable lithium battery, comprising:
a current collector; and a positive active material layer on the current collector, the positive active material layer having a first region adjacent to the current collector and a second region separated from the current collector by the first region, each of the first region and second region having a thickness equal to ½ of a total thickness of the positive active material layer, the first region having a first average pore size, the second region having a second average pore size, a ratio of the second average pore size to the first average pore size being greater than about 0.5 and less than or equal to about 1.0, and the positive electrode having an active mass density of about 2.3 g/cc to about 4.5 g/cc.

2 . The positive electrode for a rechargeable lithium battery as claimed in claim 1 , wherein:
the first average pore size is about 20 nm to about 1000 nm, and the second average pore size is about 10 nm to about 1000 nm.

3 . The positive electrode for a rechargeable lithium battery as claimed in claim 1 , wherein a ratio of a porosity of the second region to a porosity of the first region is greater than about 0.5 and less than or equal to about 1.0.

4 . The positive electrode for a rechargeable lithium battery as claimed in claim 1 , wherein:
a porosity of the first region is about 5 volume % to about 40 volume %, and a porosity of the second region is about 5 volume % to about 40 volume %.

5 . A method of preparing a positive electrode for a rechargeable lithium battery, comprising:
coating a positive active material layer composition on a current collector to obtain a coated product; drying the coated product to obtain a dried product; and compressing the dried product in a multistep compression, the multistep compression providing different active mass densities of the positive electrode following each compression and a final active mass density of the positive electrode of about 2.3 g/cc to about 4.5 g/cc.

6 . The method as claimed in claim 5 , wherein the multistep compression includes increasing the active mass density of the positive electrode with successive compressions.

7 . A negative electrode for a rechargeable lithium battery, comprising:
a current collector; and a negative active material layer on the current collector, the negative active material layer having a first region adjacent to the current collector and a second region separated from the current collector by the first region, each of the first region and second region having a thickness equal to ½ of a total thickness of the negative active material layer, the first region having a first average pore size, the second having including a second average pore size, a ratio of the second average pore size to the first average pore size being greater than about 0.5 and less than or equal to about 1.0, and the negative electrode having an active mass density of about 1.1 g/cc to about 2.29 g/cc.

8 . The negative electrode for a rechargeable lithium battery as claimed in claim 7 , wherein:
the first average pore size is about 20 nm to about 1000 nm, and the second average pore size is about 10 nm to about 1000 nm.

9 . The negative electrode for a rechargeable lithium battery as claimed in claim 7 , wherein a ratio of a porosity of the second region to a porosity of the first region is greater than about 0.5 and less than or equal to about 1.0.

10 . The negative electrode for a rechargeable lithium battery as claimed in claim 7 , wherein:
a porosity of the first region is about 5 volume % to about 40 volume %, and a porosity of the second region is about 5 volume % to about 40 volume %.

11 . A method of preparing a negative electrode for a rechargeable lithium battery, comprising:
coating a negative active material layer composition on a current collector to obtain a coated product; drying the coated product to obtain a dried product; and compressing the dried product in a multistep compression, the multistep compression providing different active mass densities of the negative electrode following each compression and a final active mass density of the negative electrode of about 1.1 g/cc to about 2.29 g/cc.

12 . The method as claimed in claim 11 , wherein the multistep compression includes increasing active mass density of the negative electrode with successive compressions.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Sohn Ju-Hee
• Lee Jin-Hyon
• Won Jung-Yeon
• Goh Eun-Young
• Lee Jong-Ki
• Park Sang-In

Classifications

• H01M4/043

  involving compressing or compaction · CPC title

• H01M4/133

  Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title

• H01M4/13 Primary

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

• H01M2004/021

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

• H01M4/139

  Processes of manufacture · CPC title