Preparation method of sulfur mesoporous silica composite material for nano-valve packaging

A technology of mesoporous silica and composite materials, applied in electrical components, battery electrodes, circuits, etc., can solve the problems of poor cycle stability, active material loss, and structural collapse of lithium-sulfur batteries, and achieve improved Coulombic efficiency and cycle stability performance, reduce structural collapse, and reduce the effect of shuttle effect

Active Publication Date: 2015-09-09
CHINA UNIV OF MINING & TECH
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Problems solved by technology

[0003] At present, the main problems of lithium-sulfur batteries are: the elemental sulfur will be reduced to polysulfides that are easily soluble in the electrolyte during the discharge process, resulting in the loss of active materials; The self-discharge of lithium metal negative electrode; the shrinkage and expansion of the positive electrode material during charge and discharge, resulting in structural collapse, all of which lead to poor cycle stability and low Coulombic efficiency of lithium-sulfur batteries (X. Ji, L. F. Nazar, J. Mater. Chem., 2010, 20, 9821-9826; A. Manthiram, Y. Fu, Y. S. Su, Acc. Chem. Res., 2012, DOI: 10.1021 / ar300179v.)
But this composite material also has some problems: the sulfur loading is low, generally around 50%, although this material shows a high discharge specific capacity relative to the sulfur content, but compared to the entire composite material, the capacity is very low. Low; the only physical adsorption between sulfur and polysulfides and porous carbon cannot fundamentally solve the problem of polysulfide dissolution

Method used

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  • Preparation method of sulfur mesoporous silica composite material for nano-valve packaging

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Experimental program
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Embodiment 1

[0021] Synthesis of mesoporous silica: Dissolve 1 g of cetyltrimethylammonium bromide (CTAB) and 4 ml of concentrated ammonia water in 40 ml of deionized water, and stir magnetically at 30 °C for 1 h to dissolve completely. Then, 2.5 ml tetraethyl orthosilicate (TEOS) was added dropwise to the solution, stirred at room temperature for 24 hours to crystallize, and the resulting precipitate was filtered, washed and dried. The dried product was extracted three times in an ethanol solution at 60°C to remove the template agent, filtered, washed, and dried to obtain the mesoporous silica material MCM-41.

[0022] Surface modification of mesoporous silica: add 100 mg of MCM-41 mesoporous material into 10 mL of anhydrous toluene, stir it with magnetic force to make it evenly dispersed, and then quickly add 0.1 mmol of organosilane molecule N-phenylamine formazan Triethoxysilane (PhAMTES) was heated under reflux at 80 °C for 24 h, filtered, washed with toluene and methanol three times ...

Embodiment 2

[0026] Synthesis of hollow spherical mesoporous silica: Take 0.5g of polyvinylpyrrolidone (PVP-10) and dissolve it in 100 mL of absolute ethanol / deionized aqueous solution with a volume ratio of 20 / 80, and magnetically stir for 1 hour to completely dissolve it ; Add 1.17g of dodecylamine (DDA) into 5 mL of absolute ethanol, mix the two solutions, continue to stir for 1 hour, then add 5 ml of tetraethyl orthosilicate (TEOS) dropwise to the mixed solution, and continue to stir After 24 hours, filter, wash, and dry, extract the dried product three times in ethanol solution at 60 °C to remove the template agent, filter, wash, and dry to obtain hollow spherical mesoporous silica with a pore size of 4 nm.

[0027] The surface treatment of the mesoporous silica, the loading of sulfur and the synthesis steps of the nano-valve are the same as in Example 1. The difference is that during the sulfur loading process, the mass ratio of mesoporous silica to sulfur is 1:3.

Embodiment 3

[0029]Surface modification of mesoporous silica: Add 100 mg of commercial SBA-15 mesoporous material into 10 mL of anhydrous toluene, stir it with magnetic force to make it evenly dispersed, and then quickly add 0.1 mmol of organosilane molecule N-phenylamine Propyltrimethoxysilane (PhAMTMS) was heated under reflux at 80 °C for 24 h, filtered, washed with toluene and methanol three times to thoroughly wash off the organic silane chain molecules adsorbed on the surface, and finally vacuum-dried to obtain the surface Modified SBA-15 mesoporous material with a pore size of 10nm.

[0030] The loading of sulfur and the synthesis of nano-valve are the same as in Example 1.

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Abstract

The invention relates to a preparation method of a sulfur mesoporous silica composite material for nano-valve packaging. The method is as below: 1, preparing a mesoporous silica carrier by using a ''template method''; 2, carrying out surface modification on mesoporous silica by using an organic silane chain molecule; 3, injecting elemental sulfur into the pore tunnel or cavity of the mesoporous silica by a vacuum heat treatment method; and 4, then sealing pores of mesoporous silica by using alpha-cyclodextrin as a nano-valve. The invention applies the composite material to lithium-sulfur battery, uses the high specific surface area of mesoporous silica to solve the problem of lower sulfur content in lithium-sulfur battery cathode material of the prior art, and inhibits volume expansion of sulfur in the process of charging and discharging; and meanwhile the introduced nano-valve can inhibit the dissolution of polysulfide and improve the cycle stability of lithium-sulfur battery.

Description

technical field [0001] The invention relates to inorganic nanometer materials and new energy materials, in particular to a method for preparing sulfur mesoporous silica composite materials encapsulated by nanometer valves. Background technique [0002] Due to the increasingly severe environmental pollution and energy crisis, the development and utilization of green new energy is a current research hotspot. Lithium-sulfur batteries have attracted much attention due to their high energy density, low cost and environmental friendliness. The theoretical specific capacity of elemental sulfur is 1672 mAh g, and the theoretical specific energy can reach 2600 Wh kg when assembled with metallic lithium. -1 [Science, 1993, 261, 1029–1032], making the battery system very promising for commercial applications. [0003] At present, the main problems of lithium-sulfur batteries are: the elemental sulfur will be reduced to polysulfides that are easily soluble in the electrolyte during the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/134H01M4/48
CPCH01M4/134H01M4/483H01M2004/021Y02E60/10
Inventor 梁华根尹诗斌罗林黄飞马静张绍良
Owner CHINA UNIV OF MINING & TECH
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