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CoMn2O4/NC/S composite material as well as preparation method thereof and application thereof as Li-S secondary battery cathode material

A composite material and cobalt salt technology, applied in secondary batteries, battery electrodes, circuits, etc., can solve problems such as low cycle stability and coulombic efficiency, battery electrode structure damage, poor conductivity of sulfur elements, etc., to reduce the shuttle effect , Promote transfer, improve life expectancy

Active Publication Date: 2018-09-07
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, its practical application is still hindered by various factors
First, sulfur has poor electrical conductivity, and the final reduction product Li 2 S 2 and Li 2 S is also an electronic insulator; secondly, during charge and discharge, S 8 The molecule is oxidized and reduced to a series of long-chain intermediates S n 2- (3≤n≤8), these intermediates are easily dissolved into the organic electrolyte, and subsequently shuttled between the positive and negative electrodes, resulting in a shuttle effect, resulting in low cycle stability and Coulombic efficiency; third, lithium in the lithiation There is obvious volume expansion (about 80%) during the process, and repeated expansion and contraction during charging and discharging will lead to the destruction of the battery electrode structure

Method used

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  • CoMn2O4/NC/S composite material as well as preparation method thereof and application thereof as Li-S secondary battery cathode material
  • CoMn2O4/NC/S composite material as well as preparation method thereof and application thereof as Li-S secondary battery cathode material
  • CoMn2O4/NC/S composite material as well as preparation method thereof and application thereof as Li-S secondary battery cathode material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] CoMn 2 o 4 Preparation of / NC / S composites:

[0042] (1) 1.455 g of cobalt nitrate hexahydrate and 3.28 g of 2-methylimidazole were dissolved in 100 mL of methanol, respectively. Then, the clear solution of 2-methylimidazole was quickly poured into the cobalt nitrate solution under vigorous stirring. After mixing well, the solution was allowed to stand at room temperature for one day. The obtained purple precipitate was centrifuged and washed 3 times with absolute ethanol, and dried at 70° C. for 12 h to obtain ZIF-67 crystals.

[0043] (2) The synthesized ZIF-67 crystal was calcined at 800 °C for 3 h under nitrogen flow, and the heating rate was 5 °C / min to obtain the Co-N-C composite material.

[0044] (3) Disperse and dissolve 0.2g of Co-N-C and 93.2mg of manganese sulfate in 35mL of deionized water, and dissolve 29.2mg of potassium permanganate in 35mL of deionized water. Hydrothermal reaction was carried out at 160°C for 12 hours in the reactor. Washed three ...

Embodiment 2

[0049] CoMn 2 o 4 Preparation of / NC / S composites:

[0050] (1) 1.455 g of cobalt nitrate hexahydrate and 1.64 g of 2-methylimidazole were dissolved in 70 mL of methanol, respectively. Then, the clear solution of 2-methylimidazole was quickly poured into the cobalt nitrate solution under vigorous stirring. After mixing well, the solution was allowed to stand at room temperature for one day. The obtained purple precipitate was centrifuged and washed 3 times with absolute ethanol, and dried at 70° C. for 12 hours to obtain ZIF-67 crystals.

[0051] (2) The synthesized ZIF-67 crystal was calcined at 700°C for 5h under nitrogen flow, and the heating rate was 3°C / min to obtain the Co-N-C composite material.

[0052] (3) Disperse and dissolve 0.15g of Co-N-C and 86.2mg of manganese sulfate in 35mL of deionized water, and dissolve 43.2mg of potassium permanganate in 35mL of deionized water. Transfer to a reaction kettle for hydrothermal reaction at 180°C for 10h. Washed three t...

Embodiment 3

[0057] CoMn 2 o 4 Preparation of / NC / S composites:

[0058] (1) 1.455 g of cobalt nitrate hexahydrate and 6.56 g of 2-methylimidazole were dissolved in 150 mL of methanol, respectively. Then, the clear solution of 2-methylimidazole was quickly poured into the cobalt nitrate solution under vigorous stirring. After mixing well, the solution was allowed to stand at room temperature for one day. The obtained purple precipitate was centrifuged and washed 3 times with absolute ethanol, and dried at 70° C. for 12 h to obtain ZIF-67 crystals.

[0059] (2) The synthesized ZIF-67 crystal was calcined at 900 °C for 2 h under nitrogen flow, and the heating rate was 5 °C / min to obtain the Co-N-C composite material.

[0060] (3) Disperse and dissolve 0.25g of Co-N-C and 46.6mg of manganese sulfate in 35mL of deionized water, and dissolve 14.6mg of potassium permanganate in 35mL of deionized water. Transfer to a reaction kettle for hydrothermal reaction at 150°C for 24h. Washed three t...

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Abstract

The invention discloses a CoMn2O4 / NC / S composite material as well as a preparation method thereof and application thereof as a Li-S secondary battery cathode material. The CoMn2O4 / NC / S composite material is formed by anchoring CoMn2O4 nanoparticles on NC (Nitrogen doped graphitized porous Carbon) and then compounding with sulfur. The preparation method comprises the following steps: carrying out roasting treatment on an MOF (Metal Organic Framework) material ZIF-67, thus obtaining a Co-N-C composite material; then carrying out hydrothermal reaction on the Co-N-C composite material, manganese salt and hypermanganate, thus obtaining a CoMn2O4 / NC composite material; further compounding with the sulfur, thus obtaining the CoMn2O4 / NC / S composite material. The CoMn2O4 / NC / S composite material disclosed by the invention is capable of simultaneously carrying out strong chemical adsorption and physical adsorption on polysulfide formed during a charging-discharging process of a Li-S secondary battery, and is capable of effectively inhibiting dissolution loss of the polysulfide, reducing the generation of a shuttle effect and prolonging the service life of the Li-S secondary battery. Meanwhile, the preparation method adopts low-cost and low-toxicity Mn to partially replace expensive and toxic Co for being applied to the Li-S secondary battery, and important innovation and practice significances are obtained.

Description

technical field [0001] The invention relates to a lithium-sulfur battery material, in particular to a CoMn 2 o 4 / NC / S composite material and its preparation method, and CoMn 2 o 4 The application of / NC / S composite material as the positive electrode material of lithium-sulfur secondary battery belongs to the field of lithium-sulfur battery. Background technique [0002] With the rapid development of portable mobile devices and electric vehicles in recent years, it has become very urgent to develop secondary battery systems with higher energy density. At present, the specific energy density of commercial lithium-ion batteries can reach 250Wh / kg, but due to the low theoretical capacity of positive electrode materials, the further improvement of energy density is greatly limited. Therefore, it is imperative to develop new battery systems. In new energy storage systems, lithium-sulfur batteries are considered to be one of the most promising candidate batteries due to their...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/525H01M4/38H01M4/583H01M4/62H01M10/0525
CPCH01M4/364H01M4/38H01M4/525H01M4/583H01M4/625H01M10/0525Y02E60/10
Inventor 钱东范凯丽刘贝贝李俊华赵丹刘桂雨
Owner CENT SOUTH UNIV
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