Method for preparing Si/C composite cathode material of lithium ion battery

A technology for lithium-ion batteries and negative electrode materials, applied in battery electrodes, circuits, electrical components, etc., can solve the problems of limiting the large-scale practical application of silicon-based materials, material morphology changes, and poor cycle performance, and achieve good cycle stability. And the effect of rate performance, cohesion enhancement and excellent performance

Active Publication Date: 2013-05-01
CENT SOUTH UNIV
View PDF3 Cites 37 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, pure silicon materials have very significant volume expansion (>300%) during the process of high lithium intercalation, the electrode materials will gradually pulverize, the alloy structure is destroyed, and the separation between silicon particles and the conduc

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Method for preparing Si/C composite cathode material of lithium ion battery
  • Method for preparing Si/C composite cathode material of lithium ion battery
  • Method for preparing Si/C composite cathode material of lithium ion battery

Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0030] Example 1

[0031] Dissolve the phenolic resin (calculated according to the pyrolysis carbon content in the composite material after sintering) in an appropriate amount of absolute ethanol, and then add the appropriate ratio of nano silicon powder and graphite to the solution, stir for 2 hours, and mix well, then put the solution at 80 It evaporates and solidifies at ℃. After the solvent is completely volatilized, a massive precursor will be obtained. After drying, it will be calcined at 800℃ for 2h under the protection of high-purity argon, and then cooled in a furnace to obtain a Si / C composite material. The synthesized Si / C composite material, conductive carbon black (SuperP) and binder (PVDF) are uniformly mixed at a mass ratio of 8:1:1, and N-methylpyrrolidone (NMP) is added to prepare a slurry and then uniformly coated On copper foil, dried at 120°C to prepare a negative electrode sheet with Φ=14mm, heat-treated at 230°C for 3h under the protection of high-purity arg...

Example Embodiment

[0034] Example 2

[0035] Dissolve glucose (calculated based on the pyrolysis carbon content in the sintered composite material) in an appropriate amount of deionized water, use cetyl ammonium bromide as the dispersant, and then add the appropriate ratio of nano silicon powder and graphite to the solution. Magnetic force After stirring for 2 hours, the uniformly dispersed suspension was spray-dried at 170~200°C to obtain the composite material precursor. The obtained precursor was calcined at 800°C for 2h under the protection of high-purity argon, and then cooled in the furnace to obtain a Si / C composite material. The synthesized Si / C composite material, conductive carbon black (Super P) and binder (PVDF) are uniformly mixed at a mass ratio of 8:1:1, and NMP is added to prepare a slurry, which is uniformly coated on the copper foil. It was dried at 120°C to prepare a negative electrode sheet with Φ=14mm, heat-treated at a low temperature of 230°C for 3h under the protection of h...

Example Embodiment

[0036] Example 3

[0037] Add pure nano silicon powder to a 2% hydrogen fluoride aqueous solution, and at the same time add a suitable amount of silver nitrate, stir it evenly and transfer it to a centrifuge tube for ultrasonic dispersion, then collect the silicon powder by high-speed centrifugation, and then use absolute ethanol The collected silicon powder is washed with deionized water several times to separate the nano-silicon from the migration solvent. After vacuum drying, the nano-silicon must be etched. The morphology comparison of nano-silicon before and after etching figure 2 Shown. Dissolve citric acid (calculated based on the pyrolysis carbon content in the sintered composite material) in an appropriate amount of deionized water, use absolute ethanol as a dispersant, and then add the etched nano-silicon powder and graphite in the solution in an appropriate ratio , Magnetic stirring for 2 hours, mixing uniformly, and spray-drying the uniformly dispersed suspension at...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

The invention discloses a method for preparing a Si/C composite cathode material of a lithium ion battery. The method is characterized in that through a liquid phase solidification-high temperature pyrolysis-low temperature treatment combined method, the Si/C composite cathode material having good cycling stability and good rate capability is prepared. Concretely, the method comprises the following steps of uniformly dispersing a silicon source (before or after etching) and graphite in an appropriate solvent in the presence of a second-type additive with control of a temperature to obtain a solid precursor after the solvent is volatilized completely, transferring the solid precursor into a protective atmosphere, carrying out pyrolysis at a high temperature so that the carbon source is pyrolyzed into amorphous carbon and forms a coating layer, carrying out furnace cooling to obtain the Si/C composite cathode material, uniformly mixing the Si/C composite cathode material, a conductive agent and a binder, coating the mixture on a pole piece, carrying out drying, carrying out low-temperature treatment, and carrying out an electrochemical performance test. The method is simple and feasible and has a high practical degree. The Si/C composite cathode material prepared by the method has a high capacity and good cycling stability and a good rate capability after the low-temperature treatment.

Description

technical field [0001] The invention belongs to the field of lithium-ion battery materials and preparation methods thereof, and relates to a lithium-ion battery silicon-carbon composite negative electrode material and a preparation method thereof. Background technique [0002] Lithium-ion batteries are widely used in various portable electronic devices and electric vehicles due to their inherent advantages, such as portability, high capacity, and small size. At present, commercial lithium-ion secondary batteries generally use various carbon materials as negative electrodes, mainly graphitized carbon and amorphous carbon, such as natural graphite, modified graphite, graphitized mesocarbon microspheres, soft carbon (such as coke) and some hard carbon etc. However, such materials have low specific capacity (such as graphite theoretical capacity 372mAh g -1 ), prone to organic solvent co-intercalation and other shortcomings, and cannot meet the needs of high energy density bat...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
IPC IPC(8): H01M4/38H01M4/583
CPCY02E60/12Y02E60/10
Inventor 王志兴苏明如郭华军李新海黄思林甘雷彭文杰张云河胡启阳
Owner CENT SOUTH UNIV
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap