Positive pole material for high-performance lithium-sulfur battery and preparation method thereof

A positive electrode material, lithium-sulfur battery technology, applied in the direction of battery electrodes, circuits, electrical components, etc., can solve the problems of shuttle phenomenon, reduce battery charge and discharge Coulombic efficiency, low capacity retention rate of lithium-sulfur battery, etc., to reduce flying Shuttle phenomenon, the effect of improving the capacity retention rate and cycle stability

Inactive Publication Date: 2013-06-12
HANGZHOU INST OF ADVANCED MATERIAL BEIJING UNIV OF CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, before the commercialization of lithium-sulfur batteries, there are still many problems to be solved, the most important of which are the low capacity retention rate and poor cycle stability of lithium-sulfur batteries during charging and discharging.
The main reason for these two problems is that during the discharge process of the battery, the elemental S in the positive electrode is reduced to produce intermediate products such as polysulfides. Coulombic efficiency
At the same time, these polysulfides will diffuse to the surface of the lithium electrode with the electrolyte and corrode the lithium (negative electrode) electrode, resulting in irreversible capacity loss.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Choose a pore size of 0.75nm and a specific surface area of ​​1698m 2 / g MOFs were degassed overnight at 170°C before use, then put into a crucible and mixed with a certain amount of sulfur, and heated up to 125°C at a heating rate of 0.2°C / min for 4 hours by the melt diffusion method to obtain the S / MOFs material , before being used as electrodes, S / MOFs with a specific surface area of ​​285m 2 / g of activated carbon at a mass ratio of 3:1 was maintained at 300 rpm for 15 min by ball milling to obtain S / MOFs / carbon materials.

[0019] Electrode preparation and performance test: The test electrode is composed of a mixture of nickel mesh and MOFs-based composite catalyst (70wt%), acetylene black (20wt%) and polyvinylidene fluoride (10wt%). The measured results are listed in Table 1 .

Embodiment 2

[0021] Choose a pore size of 2.5nm and a specific surface area of ​​5985m 2 / g MOFs were degassed overnight at 170°C before use, and then put into a crucible with a certain amount of Na 2 S mixed, heated up to 155°C at a heating rate of 2°C / min and kept for 30h by the melt-diffusion method to prepare S / MOFs materials. Before being used as electrodes, S / MOFs had a specific surface area of ​​1500m 2 / g of carbon nanotubes is hydrothermally synthesized at a mass ratio of 3:1, heated to 150°C at a heating rate of 3°C / min and kept for 30 hours, and then cooled to room temperature at a cooling rate of 2°C / min to obtain S / MOFs / carbon materials.

[0022] Electrode preparation and performance test: The test electrode is composed of a mixture of nickel mesh and MOFs-based composite catalyst (50wt%), acetylene black (40wt%) and polyvinylidene fluoride (10wt%). The measured results are listed in Table 1 .

Embodiment 3

[0024] Choose a pore size of 4nm and a specific surface area of ​​2767m 2 / g MOFs were degassed overnight at 170 °C before use, and then put into a crucible with a certain amount of C 2 S mixed, heated up to 175°C at a heating rate of 5°C / min by the melt-diffusion method and kept for 60h to prepare S / MOFs materials. Before being used as electrodes, S / MOFs had a specific surface area of ​​2300m 2 / g of graphene was kept at 600 rpm for 45 min by ball milling at a mass ratio of 3:1, and then heated to 120 °C at a heating rate of 2 °C / min for 50 h by hydrothermal synthesis, and then heated at 3 °C / min The cooling rate drops to room temperature, and the S / MOFs / carbon material is obtained.

[0025] Electrode preparation and performance test: The test electrode is composed of a mixture of nickel mesh and MOFs-based composite catalyst (60wt%), acetylene black (30wt%) and polyvinylidene fluoride (10wt%). The measured results are listed in Table 1 .

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Abstract

The invention discloses a positive pole material for a high-performance lithium-sulfur battery and a preparation method thereof. The positive pole material comprises a sulfur composite material and a carbon material. The preparation process comprises the following steps: assembling sulfur into pores of metal-organic frameworks (MOF), thus preparing the sulfur composite material; and then, loading the sulfur composite material on the carbon material. According to the invention, polysulfide generated in the charging/discharging process of a lithium-sulfur battery is limited in the pores of the MOF material, thereby reducing the shuttle phenomenon, preventing the polysulfide from migrating along with the electrolyte and improving the electric capacity and cycle performance of the lithium-sulfur battery.

Description

technical field [0001] The invention relates to a lithium-sulfur battery electrode material, in particular to a lithium-sulfur battery positive electrode material and a preparation method thereof. Background technique [0002] At present, the theoretical specific capacity of lithium-ion rechargeable batteries using lithium cobalt oxide as the positive electrode material is 275mAh / g, but the actual capacity is only 130-140mAh / g. Although it has been commercialized, the specific capacity of the battery has little room for improvement, which limits power tools. , especially the development of electric vehicles. The theoretical specific capacity of a lithium-sulfur battery mainly composed of sulfur (elemental sulfur, organic sulfur, etc.) as the positive electrode, metal lithium as the negative electrode, and electrolyte can be as high as 1675mAh / g, so lithium-sulfur batteries have gradually become a research hotspot. However, before the commercialization of lithium-sulfur batt...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58
CPCY02E60/10
Inventor 银凤翔陈标华王志清
Owner HANGZHOU INST OF ADVANCED MATERIAL BEIJING UNIV OF CHEM TECH
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