FreshPatents.com Logo
stats FreshPatents Stats
2 views for this patent on FreshPatents.com
2013: 2 views
Updated: October 13 2014
newTOP 200 Companies filing patents this week


    Free Services  

  • MONITOR KEYWORDS
  • Enter keywords & we'll notify you when a new patent matches your request (weekly update).

  • ORGANIZER
  • Save & organize patents so you can view them later.

  • RSS rss
  • Create custom RSS feeds. Track keywords without receiving email.

  • ARCHIVE
  • View the last few months of your Keyword emails.

  • COMPANY DIRECTORY
  • Patents sorted by company.

Follow us on Twitter
twitter icon@FreshPatents

Electrode for lithium secondary battery, method of manufacturing the same, and lithium secondary battery including the same

last patentdownload pdfdownload imgimage previewnext patent


20130011733 patent thumbnailZoom

Electrode for lithium secondary battery, method of manufacturing the same, and lithium secondary battery including the same


An electrode for a lithium secondary battery, the electrode including: an electrode active material; and a composite including a clay and a polymer intercalated between layers of the clay, a method of manufacturing the electrode, and a lithium secondary battery including the electrode.
Related Terms: Electrode Intercal Lithium Polymer

Browse recent Samsung Sdi Co., Ltd. patents - Yongin-si, KR
Inventors: Bum-Jin CHANG, Woon-Suk JANG, Chae-Woong CHO, Seung-Hun HAN, Ki-Jun KIM, Kwi-Seok CHOI
USPTO Applicaton #: #20130011733 - Class: 429211 (USPTO) - 01/10/13 - Class 429 
Chemistry: Electrical Current Producing Apparatus, Product, And Process > Current Producing Cell, Elements, Subcombinations And Compositions For Use Therewith And Adjuncts >Electrode >Having Connector Tab

Inventors:

view organizer monitor keywords


The Patent Description & Claims data below is from USPTO Patent Application 20130011733, Electrode for lithium secondary battery, method of manufacturing the same, and lithium secondary battery including the same.

last patentpdficondownload pdfimage previewnext patent

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 10-2011-0067532, filed on Jul. 7, 2011, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND

1. Field

One or more embodiments relate to an electrode for a lithium secondary battery, a method of manufacturing the same, and a lithium secondary battery including the electrode.

2. Description of the Related Technology

A lithium secondary battery consists of a positive electrode, a negative electrode, a separator, and an electrolyte. During charging, lithium ions are deintercalated from the positive electrode and migrate toward the negative electrode, and during discharging, lithium ions are deintercalated from the negative electrode and return to the positive electrode. The positive and negative electrodes and the electrolyte do not induce any chemical reactions.

Typically, an electrode includes a mixture including an active material for storing energy, a conducting agent for supplying electric conductivity, and a binder. In general, as an active material for the positive electrode, a lithium transition metal oxide is used, and as an active material for the negative electrode, a carbonaceous active material is used. To manufacture the electrode, the mixture is mixed with a solvent to prepare a slurry, and then the slurry is coated and dried on a current collector. In this case, the binder improves dispersion of the conducting agent, an adhesive force between active material particles, between the active material and the current collector, and between the active material and the conducting agent, and conductivity of the conducting agent.

As the binder, a fluorine-based polymer material that is insoluble with respect to an organic electrolytic solution and is chemically stable, such as polyvinylidene fluoride (PVdF), is widely used.

However, if the fluorine-based polymer material, such as PVdF, is used as the binder, since chains of the fluorine-based polymer material are entangled, the binder has a high swelling ratio that indicates a degree to which the binder swells when the electrolytic solution permeates thereinto. Also, due to the interaction between the chains, when a nano-sized active material and the conducting agent are used, the solvent may separately leak out. Also, the swollen binder leads to an increase in a distance between active material particles, thereby increasing resistance of an electrode including the binder.

SUMMARY

One or more embodiments include an electrode for a lithium secondary battery in which polymer chains are less entangled and which swells less with respect to an electrolytic solution, a method of manufacturing the same, and a lithium secondary battery including the electrode.

Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.

According to one or more embodiments, an electrode for a lithium secondary battery, includes: an electrode active material; and a composite including a clay and a polymer intercalated between layers of the clay.

According to one or more embodiments, a method of manufacturing an electrode for a lithium secondary battery includes: preparing a clay dispersion by dispersing clay in a first solvent; preparing a composite by mixing the clay dispersion with a polymer or a polymer solution prepared by dissolving the polymer in a second solvent: preparing a composition for forming an electrode active material layer by adding an electrode active material to the composite and mixing the electrode active material and the composite; and coating and drying the composition on a current collector to form an electrode active material layer.

According to one or more embodiments, a method of manufacturing an electrode for a lithium secondary battery includes: melting clay and a polymer by using a heat treatment; extruding the molten product to form a composite; preparing a composition for forming an electrode active material layer by dissolving the composite in a third solvent, adding an electrode active material thereto, and mixing the resultant mixture; and coating and drying the composition on a current collector to form an electrode active material layer.

According to one or more embodiments, a lithium secondary battery includes the electrode.

The electrode may be a positive electrode.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a conceptual view of a composite included in an electrode for a lithium secondary battery, according to an embodiment;

FIG. 2 is a schematic view of a lithium ion battery according to an embodiment;

FIGS. 3 and 4 show changes in impedance when lithium batteries manufactured according to Example 1 and Comparative Example 1 are charged and discharged, respectively;

FIG. 5 is a graph of discharge capacities of coin cells manufactured according to Example 1 and Comparative Example 1; and

FIG. 6 is a graph of lifetime characteristics of coin cells manufactured according to Example 1 and Comparative Example 1.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present description.

An electrode according to an embodiment includes an electrode active material and a composite including a clay and a polymer intercalated between layers of the clay.

The electrode may include a conducting agent.

The electrode may be a positive electrode.

FIG. 1 is a conceptual view of a composite 10 included in an active material layer included in an electrode for a lithium secondary battery, according to an embodiment, before and after swelling of the composite 10.

Referring to FIG. 1, the composite 10 includes a polymer 11 and a clay 13, and the polymer 11 is intercalated between layers of the clay 13.

In FIG. 1, the polymer 11 is introduced to a conducting agent 15.

The clay 13 has a layered structure. In this regard, an interlayer distance of the clay 13 may be from about 1 to about 10 nm. If the interlayer distance is within this range, the polymer may be easily intercalated between layers of the clay 13.

Since the polymer 11 is present between layers of the clay 13 having a restricted distance, chains of the polymer 11 present between the layers of the clay 13 are not entangled, and thus, all chains of the polymer are less entangled. If an electrolytic solution permeates into the composite 10 when the chains of the polymer 11 are entangled, the polymer 11 swells more due to adjacent chains of the polymer 11. However, if an electrolytic solution permeates into the composite 10 when the chains of the polymer 11 are not entangled, since the number of adjacent chains of the polymer 11 is relatively decreased, a swelling degree of the polymer 11 is decreased compared to when the polymer 11 is not intercalated between layers of the clay 13. Accordingly, even when the electrolytic solution permeates into the composite 10, a swelling degree of an electrode mixture remains at a moderate level.

The term “electrode mixture” refers to a mixture including the electrode active material and the composite. If an electrode includes a conducting agent, the term “electrode mixture” refers to a mixture including the electrode active material, the composite, and the conducting agent.

A swelling ratio of the electrode mixture may be from about 1 to about 8%.

The swelling ratio of the electrode mixture is measured as follows: a formation capacity evaluation is performed on a battery, the battery is dissembled, and then the electrolytic solution is removed from the battery and a thickness of an electrode plate is measured.

During the permeation of the electrolytic solution, the swelling ratio of the polymer 11 is reduced and thus, in the composite used as the binder, a distance between active material particles is not increased, thereby preventing an increase in resistance of the electrode.

The resistance of the electrode including the composite is from about 5 to about 30% lower than that of an electrode that is generally used.

Hereinafter, an electrode according to another embodiment will be described in detail. First, materials that are used in the electrode mixture will be described in detail.

Examples of the electrode active material are a LFP-based material such as lithium iron phosphate (LiFePO4), a LCO-based material such as lithium cobalt oxide (LiCoO2), a LMO-based material such as lithium manganese oxide (LiMnO2), a LNO-based material such as lithium nickel oxide (LiNiO2), an NCM-based material such as lithium nickel cobalt manganese oxide (LiNiCoMnO2), and a mixture thereof. However, the electrode active material is not limited to the materials described above.

The clay may include at least one selected from the group consisting of montmorillonite, bentonite, saponite, beidellite, nontronite, hectorite, and stevensite.

The polymer may include at least one selected from the group consisting of polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), and polyacrylic acid (PAA). A weight average molecular weight of the polymer is from about 100,000 to about 1,000,000.

Substituents of the polymers may enhance an adhesive force with respect to a substrate.

An amount of the composite may be from about 0.1 to about 20 parts by weight, for example, about 0.2 to about 1 part by weight, based on 100 parts by weight of the electrode active material. If the amount of the composite is within the ranges described above, the swelling of the electrode mixture is suppressed without an increase in resistance of the electrode and thus, the formed electrode has excellent conductivity and mechanical characteristics.

The electrode may further include a conducting agent.

As the conducting agent, a carbonaceous material may be used. An example of the carbonaceous material is vapor grown carbon fiber (VGCF), acetylene black, carbon nanotube (CNT), or the like

An amount of the conducting agent may be from about 1 to about 10 parts by weight based on 100 parts by weight of the electrode active material. As described above, although the amount of the conducting agent is smaller than a level that is generally used in the art, the formed electrode has excellent conductivity.

A method of manufacturing an electrode for a lithium secondary battery, according to an embodiment, will now be described in detail.

A composite in which a polymer is intercalated in clay is prepared by solution intercalation.

First, clay is dispersed in a first solvent at a temperature of about 40 to about 60° C. to prepare a clay dispersion. An example of the first solvent is N-methylpyrrolidone (NMP).



Download full PDF for full patent description/claims.

Advertise on FreshPatents.com - Rates & Info


You can also Monitor Keywords and Search for tracking patents relating to this Electrode for lithium secondary battery, method of manufacturing the same, and lithium secondary battery including the same patent application.
###
monitor keywords



Keyword Monitor How KEYWORD MONITOR works... a FREE service from FreshPatents
1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored.
3. Each week you receive an email with patent applications related to your keywords.  
Start now! - Receive info on patent apps like Electrode for lithium secondary battery, method of manufacturing the same, and lithium secondary battery including the same or other areas of interest.
###


Previous Patent Application:
Copper foil for negative electrode current collector of secondary battery
Next Patent Application:
Lithium inks and electrodes and batteries made therefrom
Industry Class:
Chemistry: electrical current producing apparatus, product, and process
Thank you for viewing the Electrode for lithium secondary battery, method of manufacturing the same, and lithium secondary battery including the same patent info.
- - - Apple patents, Boeing patents, Google patents, IBM patents, Jabil patents, Coca Cola patents, Motorola patents

Results in 0.66303 seconds


Other interesting Freshpatents.com categories:
QUALCOMM , Monsanto , Yahoo , Corning ,

###

Data source: patent applications published in the public domain by the United States Patent and Trademark Office (USPTO). Information published here is for research/educational purposes only. FreshPatents is not affiliated with the USPTO, assignee companies, inventors, law firms or other assignees. Patent applications, documents and images may contain trademarks of the respective companies/authors. FreshPatents is not responsible for the accuracy, validity or otherwise contents of these public document patent application filings. When possible a complete PDF is provided, however, in some cases the presented document/images is an abstract or sampling of the full patent application for display purposes. FreshPatents.com Terms/Support
-g2-0.1916
     SHARE
  
           

FreshNews promo


stats Patent Info
Application #
US 20130011733 A1
Publish Date
01/10/2013
Document #
13540160
File Date
07/02/2012
USPTO Class
429211
Other USPTO Classes
429217, 427 58, 264133
International Class
/
Drawings
7


Electrode
Intercal
Lithium
Polymer


Follow us on Twitter
twitter icon@FreshPatents