Co-HCS/CNT/S composite lithium-sulfur battery positive electrode material and preparation method thereof

A positive electrode material and composite material technology, which is applied in the field of Co-HCS/CNT/S composite lithium-sulfur battery positive electrode material and its preparation, can solve the problems of poor battery cycle life, poor rate performance, and low sulfur utilization rate, etc.

Pending Publication Date: 2021-05-11

QILU UNIV OF TECH

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AI-Extracted Technical Summary

Problems solved by technology

However, problems such as sulfur conductivity and the shuttle effect of soluble lithium polysulfides can lead to poor rate performance and fast capacity fading, ...

Abstract

The invention relates to a Co-HCS/CNT/S composite lithium-sulfur battery positive electrode material and a preparation method thereof, hollow carbon nanospheres (HCS) are attached to hollow carbon nanotubes (CNT) in the positive electrode material, and HCS is doped with Co and S and is loaded on the surface of the composite material. The preparation method comprises the following steps: (1), preparing a precursor; (2), obtaining a SiO2@Co-HCS/CNT intermediate; (3), carrying out treatment to obtain Co-HCS/CNT; and (4), obtaining the Co-HCS/CNT/S composite lithium-sulfur battery positive electrode material. Co is used as a catalyst, the oxidation-oxidation reduction reaction of a polymer can be promoted and efficient chemical adsorption of polysulfide can be provided, the loading capacity of sulfur can be improved through the special structure of HCS/CNT, meanwhile, efficient transmission of lithium ions and electrons can be provided through the special hollow structure, and the utilization rate of sulfur is improved. Further, the oxidation-reduction reaction is accelerated.

Application Domain

Electrode thermal treatmentPositive electrodes +1

Technology Topic

Lithium–sulfur batteryPolymer +11

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Examples

Experimental program(2)
Comparison scheme(1)

Example Embodiment

[0028]Example 1: A CO-HCS / CNT / S composite lithium sulfur battery positive material and a preparation method thereof

[0029]Specifically, the following steps:

[0030](1) 3 mL of tetraproprutate, 70 mL ethanol, 10 ml H2O and 3 mL, 5% (wt%) NH3· H2O was stirred for 15 minutes; 0.4 G-bandphenol, 0.56 mL, 37% wt% formaldehyde, 0.1 g ppy, 0.2 g CO (NO3)2· 6h2O, stirred for 24 hours; centrifugation, washing, drying.

[0031]The synthesis method of PPY is as follows:

[0032]0.1G methyl orange, 1.96 g fecl3150 mL deionized water, 500 μL of pyrrole monomer, was stirred at room temperature 24 h. Centrifuge, wash, dry.

[0033](2) Annealed in an argon atmosphere of 700 ° C for 5 hours to get SiO2@ Co-HCS / CNT.

[0034](3) SIO2@ Co-HCS / CNT, 2 mol / L sodium hydroxide solution mixed for 36 hours, dried after centrifugation. Get CO-HCS / CNT.

[0035](4) Mix the sulfur powder and CO-HCS / CNT in mass ratio of 7: 3, under an argon atmosphere, 155 ° C for 12 hours, and then heat the sample at 200 ° C for 30 min.

[0036]The prepared CO-HCS / CNT / S composite is a positive material of the lithium sulfur battery, which is mixed with acetylene black, and PVDF is mixed according to 7: 2: 1 ratio, and a quantity solvent (nitroxylpyrrolidone) is added dropwise. Mixed uniform ball milling, drying, slice, sliced, using the resulting electrode sheet for battery pack to obtain a battery for testing.

[0037]Scanning electronic microscope

[0038]The CO-HCS / CNT crystal phase obtained by step (3) is scanned electron microscopy.figure 1 Hollow carbon nanospheres (HCS), Co doped on the composite.

Example Embodiment

[0050]Example 2: Co-HCS / CNT / S composite lithium sulfur battery positive material and preparation method thereof

[0051]Specifically, the following steps:

[0052](1) 2 mL of tetraproprut ester, 46.6 mL ethanol, 6.66 ml H2O and 2 ml, 5% wt% NH3· H2O was stirred for 15 minutes; add 0.13 g of benzene diphenol, 0.37 mL, 37% wt% formaldehyde, 0.2 g of PPY, 0.13 g CO (NO3)2· 6h2O, stirred for 24 hours; centrifugation, washing, drying.

[0053]The synthesis method of PPY is as follows:

[0054]0.1G methyl orange, 1.96 g fecl3150 mL deionized water, 500 μL of pyrrole monomer at room temperature for 24 h; centrifugation, washing, drying.

[0055](2) Annealed in an argon atmosphere of 700 ° C for 5 hours to get SiO2@ Co-HCS / CNT.

[0056](3) SiO2 @ Co-HCS / CNT, 2 mol / L sodium hydroxide solution was mixed for 36 hours, and dried after centrifugation.

[0057](4) Mix the sulfur powder and CO-HCS / CNT in mass ratio of 7: 3. In the argon atmosphere, 155 ° C was charged 12 hours; then the sample was charged at 200 ° C for 30 min.

[0058]The prepared CO-HCS / CNT / S composite is a positive material of the lithium sulfur battery, which is mixed with acetylene black, and PVDF is mixed according to 7: 2: 1 ratio, and a quantity solvent (nitroxylpyrrolidone) is added dropwise. Mixed uniform ball milling, drying, slice, sliced, using the resulting electrode sheet for battery pack to obtain a battery for testing.

[0059]The lithium sulfur battery obtained by the lithium sulfur battery obtained by the present invention is prepared by a lithium sulfur battery prepared by the positive material of the Comparative Example 1 to test its cycle stability. By a comparison of the electrical properties of the present invention, it can be seen that the positive electrode material of the comparative example 1 is prepared by the cycle performance of lithium sulfur battery is much smaller than the electrical properties of the present invention, and the hollow tube and hollow ball structure are retained in the present invention. More excellent coating, and doped CO, doped CO serves as a catalytic effect, promoting the redox reaction, thereby improving the capacity and cycle performance of the battery.

PUM

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