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Negative active material for rechargeable lithium battery, method of preparing the same, and rechargeable lithium battery including the same

a rechargeable lithium battery and negative active material technology, applied in the direction of electrode manufacturing process, cell components, coatings, etc., can solve the problems of low energy density per unit volume, low density of graphite active material, etc., and achieve excellent coulomb efficiency, rate capability, and cycle life characteristics.

Inactive Publication Date: 2011-03-31
UNIST ULSAN NAT INST OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a negative active material for a rechargeable lithium battery with excellent coulomb efficiency, rate capability, and cycle life characteristics. The material includes an inner layer, a carbon layer outside the inner layer, and an outer layer disposed on the carbon layer. The materials in the inner and outer layers can doping and dedoping lithium. The negative active material has a hollow part inside the inner layer and the carbon layer outside the inner layer is amorphous. The method for preparing the material includes preparing a tube-shaped template with a hollow part, forming an outer layer including a material capable of doping and dedoping lithium inside the template, and annealing the template. The rechargeable lithium battery using this material has good performance characteristics.

Problems solved by technology

However, a graphite active material has a low density of 1.6 g / cc and consequently a low capacity in terms of energy density per unit volume when the graphite is used as a negative active material.

Method used

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  • Negative active material for rechargeable lithium battery, method of preparing the same, and rechargeable lithium battery including the same
  • Negative active material for rechargeable lithium battery, method of preparing the same, and rechargeable lithium battery including the same
  • Negative active material for rechargeable lithium battery, method of preparing the same, and rechargeable lithium battery including the same

Examples

Experimental program
Comparison scheme
Effect test

preparation example 1

Preparation of Silicon Modified with a Butyl Group

[0101]30 g of SiCl4 (purity of 99.999%, Aldrich Co.) was completely mixed with 100 g of 1,2-dimethoxyethane. The mixed solution was decanted with a sodium naphthalide solution and then refluxed at 400° C. for 1 hour. The resulting solution was mixed with 40 ml of a n-butyllithium, a Grignard agent. The mixture was agitated for one night. Herein, the n-butyllithium reacted with SiCl4 and formed silicon modified with a butyl group. Then, the solvent and the naphthalene were removed by heating the mixture under vacuum at 120° C. with a rotating evaporator. In addition, NaCl and LiCl byproducts were removed using an excess amount of n-hexane and water. The final product, silicon modified with a butyl group, was a light yellow viscous gel.

example 1

Preparation of a Negative Active Material for a Rechargeable Lithium Battery

[0102]An alumina (Anodisc, Whatman Co.) template having a hollow part with a 250 nm diameter was immersed in a 0.6M SnCl4 aqueous solution (Aldrich 99%) under an air atmosphere for 4 hours. The alumina template having a hollow part was positioned on a filtering sheet and treated under vacuum for 10 minutes. Next, it was dried at 150° C. for 3 hours and then calcinated at 600° C. under an air atmosphere for 3 hours. Therefore, the alumina template having a hollow part may include an outer layer including SnO2 inside.

[0103]The template including an outer layer including SnO2 inside was immersed in a solution prepared by mixing the silicon gel modified with a butyl group (butyl-capped Si) according to Preparation Example 1 with hexane in a weight ratio of 50:50 for 30 minutes, and then positioned on a filtering sheet and treated under vacuum for 10 minutes. Next, it was dried at 150° C. under vacuum. The immers...

example 2

Preparation of a Negative Active Material for a Rechargeable Lithium Battery

[0104]An alumina (Anodisc, Whatman Co.) template having a hollow part with a 250 nm diameter was immersed in a 0.6M SnCl4 aqueous solution (Aldrich 99%) for 4 hours under an air atmosphere. The alumina template having a hollow part was positioned on a filtering sheet and treated under vacuum for 10 minutes. It was dried at 150° C. for 3 hours and calcinated at 600° C. under an air atmosphere for 3 hours. Thus, an outer layer including SnO2 was formed inside the alumina template having a hollow part.

[0105]The template including a SnO2-containing outer layer inside was immersed in a solution prepared by mixing a silicon gel modified with a butyl group (butyl-capped Si) according to Preparation Example 1 with hexane in a weight ratio of 30:70 for 10 minutes, and then positioned on a filtering sheet and treated under vacuum for 10 minutes. Then, it was dried at 150° C. under vacuum. The immersing and drying proc...

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Abstract

The present invention provides a negative active material for a rechargeable lithium battery, including an inner layer including a material being capable of doping and dedoping lithium, a carbon layer outside the inner layer, and an outer layer disposed on the carbon layer and including a material being capable of doping and dedoping lithium. The materials being capable of doping and dedoping lithium included in the inner layer and in the outer layer may be the same or different from each other.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims priority to and the benefit of Korean Patent Application No. 10-2009-0093504 filed in the Korean Intellectual Property Office on Sep. 30, 2009, the entire content of which is incorporated herein by reference.BACKGROUND OF THE INVENTION[0002](a) Field of the Invention[0003]This disclosure relates to a negative active material for a rechargeable lithium battery, a method of preparing the same, and a rechargeable lithium battery including the same.[0004](b) Description of the Related Art[0005]Batteries generate electrical power using an electrochemical reaction material for a positive electrode and a negative electrode. Rechargeable lithium batteries generate electrical energy from changes of chemical potential during the intercalation / deintercalation of lithium ions at the positive and negative electrodes.[0006]The rechargeable lithium batteries include materials that reversibly intercalate or deintercalate lithium io...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): H01M4/58B05D5/12
CPCH01M4/0473H01M4/134H01M4/1395H01M4/366H01M4/0402H01M4/625H01M10/052H01M2004/021Y02E60/122H01M4/38H01M4/386H01M4/387Y02E60/10H01M4/04H01M4/36H01M10/05
Inventor CHO, JAEPHILPARK, MI HEE
Owner UNIST ULSAN NAT INST OF SCI & TECH
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