Method for preparing lithium-sulfur battery positive electrode material of composite metal organic framework

An organic framework and lithium-sulfur battery technology, applied in the field of material chemistry, can solve the problems of poor cycle performance of lithium-sulfur batteries, corrosion of metal lithium, loss of active materials, loss of active materials, etc., to improve redox reaction kinetics, excellent cycle Stability, the effect of inhibiting the shuttle effect

Active Publication Date: 2020-02-07
INT ACAD OF OPTOELECTRONICS AT ZHAOQING SOUTH CHINA NORMAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Although sulfur cathode materials have a series of advantages, there are still many problems in the commercial application of sulfur electrodes: (1) The conductivity of elemental sulfur is extremely poor, resulting in low utilization of sulfur
(2) Elemental sulfur and the final discharge product Li 2 The large difference in the density of S leads to significant volume expansion and contraction (about 80%) of the sulfur electrode during the cycle, causing the electrode material to fall off and break during the cycle, which in turn destroys the overall structure of the electrode, resulting in the formation of active substances. Loss
(3) The discharge intermediate product of the sulfur electrode (high-valence lithium polysulfide) has high solubility in the organic electrolyte, and can pass through the separator to reach the negative electrode and lithium to further generate insoluble low-valent lithium sulfide, and attach to the negative electrode On the lithium sheet, a "shuttle effect" occurs, which leads to the corrosion of metal lithium and the loss of active materials, as well as poor cycle performance of lithium-sulfur batteries and serious self-discharge phenomenon

Method used

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  • Method for preparing lithium-sulfur battery positive electrode material of composite metal organic framework
  • Method for preparing lithium-sulfur battery positive electrode material of composite metal organic framework

Examples

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Effect test

Embodiment example 1

[0029] Step 1: Synthesize ZIF67 material:

[0030] 1.145g Co(NO 3 ) 2 ·6H 2 O was dissolved in 125ml of methanol, stirred until completely dissolved to obtain Co(NO 3 ) 2 ·6H 2 O solution. 1.640 g of 2-methylimidazole (Hmim) was dissolved in 125 mL of methanol, and stirred until completely dissolved to obtain a 2-methylimidazole solution. Pour the 2-methylimidazole solution slowly into Co(NO 3 ) 2 ·6H 2 In the O solution, stir for 30 min. After the purple clear liquid turns into a purple turbid liquid, leave it to stand and age for 24 hours, and centrifuge to collect the precipitate. Subsequently, it was washed 5 times with methanol, 2 times with ethanol, and dried in vacuum at 60° C. for 24 hours to obtain ZIF67 material.

[0031] Step 2: Synthesize ZIF67 / ZnO material:

[0032] 0.3864g Zn(CH 3 COO) 2 ·H 2 O was added to 50ml methanol, put on the heating plate at 65℃ and stirred until completely dissolved to obtain Zn(CH 3 COO) 2 ·H 2 O solution. Put 0.2384g of KOH into 40ml of me...

Embodiment example 2

[0038] Step 1: Synthesize ZIF67 material:

[0039] 1.145g Co(NO 3 ) 2 ·6H 2 O was dissolved in 125ml of methanol, stirred until completely dissolved to obtain Co(NO 3 ) 2 ·6H 2 O solution. 1.640 g of 2-methylimidazole (Hmim) was dissolved in 125 mL of methanol, and stirred until completely dissolved to obtain a 2-methylimidazole solution. Pour the 2-methylimidazole solution slowly into Co(NO 3 ) 2 ·6H 2 In the O solution, stir for 30 min. After the purple clear liquid turns into a purple turbid liquid, leave it to stand and age for 24 hours, and centrifuge to collect the precipitate. Then it was washed with methanol for 5 times by centrifugation, and washed with ethanol for 2 times, and dried in vacuum at 60° C. for 24 hours to obtain the ZIF67 material.

[0040] Step 2: Synthesis of ZIF67 / ZnO:

[0041] 0.3864g Zn(CH 3 COO) 2 ·H 2 O was added to 50ml methanol, put on the heating plate at 65℃ and stirred until completely dissolved to obtain Zn(CH 3 COO) 2 ·H 2 O solution. Put 0.238...

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Abstract

The invention relates to a method for preparing a lithium-sulfur battery positive electrode material of a composite metal organic framework. The composite material consists of two metal organic frameworks, namely ZIF67 (zeolitic imidazolate framework 67) and ZIF8, and the lithium-sulfur battery positive electrode material is prepared by compounding the two metal organic frameworks with elemental sulfur. The material can be prepared by using a simple and convenient hydrothermal method through synthesis, and is capable of well adsorbing lithium polysulfide, inhibiting the "shuttling effect" of the lithium polysulfide and promoting the redox reaction kinetics of a lithium-sulfur battery in the charge / discharge process, so that the discharge capacity of the battery is increased, and the circulation stability is improved.

Description

Technical field [0001] The invention relates to a method for preparing a composite metal-organic framework material applied to a lithium-sulfur battery anode. The composite material is specifically composed of two metal-organic frameworks, ZIF67 and ZIF8, and belongs to the field of material chemistry. Background technique [0002] With the continuous emergence of new technologies, new energy products have attracted more and more attention. People put forward higher requirements for the energy density and rapid charge-discharge capability of commercial batteries. Currently, commercial lithium-ion batteries cannot meet people's needs due to their low energy density. However, when elemental sulfur is used as the cathode material, the theoretical energy density of the battery is as high as 2600Wh / kg, the theoretical specific capacity can reach 1675mA·h / g, and sulfur is abundant in nature, low-priced and non-toxic. Therefore, lithium-sulfur batteries are used by scholars. It is con...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08G83/00H01M4/62H01M10/052
CPCC08G83/008H01M4/624H01M4/628H01M10/052Y02E60/10
Inventor 钊妍邱伟龙
Owner INT ACAD OF OPTOELECTRONICS AT ZHAOQING SOUTH CHINA NORMAL UNIV
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