Flexible high-sulfur load self-repairing cathode structure for lithium-sulfur battery and preparation method of flexible high-sulfur load self-repairing cathode structure

A lithium-sulfur battery and self-repairing technology, which is applied in the field of electrochemical batteries, can solve the problems that cannot reflect high specific capacity and high specific energy density, limit the commercial application of lithium-sulfur batteries, and do not consider the application of lithium-sulfur batteries, etc., to achieve relief The effects of mechanical damage resistance, large application value, and strong electrolyte storage capacity

Active Publication Date: 2015-11-25
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, it will cause the mass fraction of the active material sulfur in the entire electrode to decrease, and the surface density of the active material will decrease after being made into the positive electrode sheet of the lithium-sulfur battery, etc., and then cannot reflect its advantages of high specific capacity and high specific energy density, thus limiting Commercial application of lithium-sulfur batteries
At the same time, the relevant design does not consider the application of lithium-sulfur batteries in flexible batteries. The reported preparation method of lithium-sulfur electrodes is basically to directly coat the active material slurry on the metal aluminum foil.
The repeated deformation of the active material and the current collector in the electrode can easily lead to the separation of the active material and damage the integrity of the pole piece, resulting in a sharp deterioration in the performance of the lithium-sulfur battery device

Method used

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  • Flexible high-sulfur load self-repairing cathode structure for lithium-sulfur battery and preparation method of flexible high-sulfur load self-repairing cathode structure
  • Flexible high-sulfur load self-repairing cathode structure for lithium-sulfur battery and preparation method of flexible high-sulfur load self-repairing cathode structure
  • Flexible high-sulfur load self-repairing cathode structure for lithium-sulfur battery and preparation method of flexible high-sulfur load self-repairing cathode structure

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] First, use nickel foam as a template (75mm×75mm×1.9mm, the pore size distribution is about 110PPI, and the surface density is about 300g / m 2 ), adopt CVD method, obtain the nickel foam of surface coating graphene, the average thickness of growth graphene film is about 100nm.

[0036] Then, the polydimethylsiloxane and the dibutyltin dilaurate curing agent were diluted in ethyl acetate according to the volume ratio of (10:1) to obtain a polymer diluent. The high molecular polymer dilution was coated on the graphene-coated nickel foam by pulling and impregnating, and dried and cured in an oven at 80°C for 6 hours. Then put it into 3mol / L hydrochloric acid solution, react at 80°C for 12 hours to dissolve the foamed nickel template, and finally obtain a graphene / polymer flexible foam with self-healing ability. It can be seen from the macroscopic photos that the obtained graphene / polymer completely replicates the morphology and structure of the metal foam template, as shown...

Embodiment 2

[0042] The difference from Example 1 is that the carbon / sulfur active material slurry formed by mixing sulfur: conductive carbon black: binder (polyvinylidene fluoride) in a weight ratio of 7:2:1 is poured into the The graphene / polymer flexible foam was vacuum-dried at 70°C for 12 hours to obtain a three-dimensional flexible high-sulfur-loaded self-healing cathode for a lithium-sulfur battery. figure 2 (a), the surface density of the active substance sulfur is increased to 6.1mg / cm 2 . Rate performance curves of three-dimensional flexible high-sulfur-loaded self-healing cathodes of lithium-sulfur batteries at different current densities ( Figure 6 ), at 300mA·g -1 Under the highest current density, the initial discharge capacity can reach 1200mAh·g -1 , see the discharge capacity at various current densities Figure 6 , at 6000mA·g -1 Discharge capacity at current density exceeds 500mAh·g -1 , showing superior rate performance, after the rate test continued at 750mA·g ...

Embodiment 3

[0046] The difference from Example 1 is:

[0047] Polydimethylsiloxane and dibutyltin dilaurate were replaced by polyamide-polyester copolymers to enhance the flexibility of the three-dimensional graphene network and impart certain self-healing properties. The reaction process is as follows: the dimer acid is first mixed with diethylenetriamine, and the end of the reactant is NH 2 oligomers. Then the oligomer (M-NH 2 t) React with urea, control the amount of urea added and the reaction time, dilute it with toluene, apply the diluted solution to the graphene-coated nickel foam by spraying, and dry it in an oven at 80°C Cured for 10h. Then put it into 3mol / L hydrochloric acid solution, and react at 80°C for 12 hours to dissolve the foamed nickel template, and a self-healing graphene / polymer flexible foam with dynamic hydrogen bonds can be obtained.

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Abstract

The invention discloses a flexible high-sulfur load self-repairing cathode structure for a lithium-sulfur battery and a preparation method of the flexible high-sulfur load self-repairing cathode structure, and belongs to the field of electrochemical batteries. The lithium-sulfur battery cathode structure disclosed by the invention is composed of graphene/high-molecular polymer flexible foam and a carbon/sulfur active material layer, wherein the active material is sulfur; and the graphene/high-molecular polymer flexible foam provides strength and a self-repairing function. The flexible high-sulfur load self-repairing cathode structure has the characteristics that a multicomponent integrated design of the lithium-sulfur battery is realized; the electrochemical property is ensured; meanwhile, the content of sulfur is increased; high active material surface density of the battery is realized; the obtained lithium-sulfur battery has the advantages of high specific capacity and high specific energy density, and simultaneously has flexibility and self-healing characteristics; the preparation process of the flexible high-sulfur load self-repairing cathode structure is simple and easy to control; large-scale and low-cost preparation can be realized; and the application value is wide.

Description

technical field [0001] The invention belongs to the technical field of electrochemical batteries, and in particular relates to a flexible high-sulfur-loaded self-repairing positive electrode structure of a lithium-sulfur battery and a preparation method thereof. Background technique [0002] At present, mobile electronic products will be developed in a thin and flexible direction, and wearable electronic products may be used on a large scale in the near future. Correspondingly, as the power source of next-generation flexible electronic products, the research and development of high-performance flexible energy storage devices represented by flexible lithium-ion batteries have attracted more and more attention. The current commercial lithium-ion batteries mainly use positive electrode materials such as lithium cobaltate, lithium manganate and lithium iron phosphate, but the mass specific energy density of lithium-ion batteries assembled from these electrode materials is genera...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/139H01M4/13
CPCY02E60/10
Inventor 李峰闻雷李璐周光敏马超群任文才成会明
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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