阅读说明：本技术 一种制备高载硫量电极材料硫-二氧化钛-聚吡咯的方法 (Method for preparing high-sulfur-content electrode material sulfur-titanium dioxide-polypyrrole ) 是由 郭瑞松 李福运 于 2019-10-09 设计创作，主要内容包括：本发明公开了一种制备高载硫量电极材料硫-二氧化钛-聚吡咯的方法,首先制备细菌纤维素气凝胶,随后,将其浸泡在钛酸丁酯的异丙醇溶液,之后再把浸泡好的细菌纤维素放入异丙醇水溶液中,反应结束后,进行冷冻干燥样品,烧结后得到三维TiO<Sub>2</Sub>纳米管,然后将三维TiO<Sub>2</Sub>纳米管在155℃氩气氛围下浸入硫,得到S-TiO<Sub>2</Sub>,最后在冰水浴中,通过过硫酸铵氧化,在S-TiO<Sub>2</Sub>表面合成一层PPy薄膜,形成S-TiO<Sub>2</Sub>-PPy电极材料。本发明利用生物材料BC成功合成三维TiO<Sub>2</Sub>纳米管,继而合成高载硫的S-TiO<Sub>2</Sub>-PPy电极材料。本发明制备方法,快速合成高载硫量的电极材料,且环境友好,避免了通过化学试剂调控合成而造成的环境污染、较长的制备时间与高昂的设备以及实验耗材的损耗等问题。(The invention discloses a method for preparing a high-sulfur-loading electrode material sulfur-titanium dioxide-polypyrrole, which comprises the steps of firstly preparing bacterial cellulose aerogel, then soaking the bacterial cellulose aerogel in isopropanol solution of butyl titanate, then putting the soaked bacterial cellulose into isopropanol water solution, after the reaction is finished, freeze-drying a sample, and sintering to obtain three-dimensional TiO 2 Nanotube and then three-dimensional TiO 2 The nano tube is immersed into sulfur at 155 ℃ under argon atmosphere to obtain S-TiO 2 Finally in an ice-water bath, by oxidation with ammonium persulphate, on S-TiO 2 Synthesizing a PPy film on the surface to form S-TiO 2 -PPy electrode material. The invention successfully synthesizes the three-dimensional TiO by utilizing the biological material BC 2 Nanotube, followed by synthesis of S-TiO with high sulfur loading 2 -PPy electrode material. The preparation method disclosed by the invention can be used for quickly synthesizing the electrode material with high sulfur carrying capacity, is environment-friendly, and avoids the problems of environmental pollution, long preparation time, high equipment and high consumption of experimental consumables and the like caused by regulation and control of synthesis through chemical reagents.)

1. A method for preparing a high-sulfur-content electrode material, namely sulfur-titanium dioxide-polypyrrole is characterized by comprising the following steps:

step one, preparing bacterial cellulose aerogel: mixing isopropanol and butyl titanate according to the volume ratio of 100mL: 3-7 mL, stirring the mixture by using magnetons to form a uniform mixed solution, and then soaking the bacterial cellulose cut into small pieces in the mixed solution for 2 days to obtain the bacterial cellulose aerogel;

step two, preparing three-dimensional TiO₂Nanotube: mixing isopropanol and water according to the volume ratio of 9:1, stirring the mixture by using magnetons to form a uniform isopropanol aqueous solution, quickly washing the bacterial cellulose soaked in the step one by using isopropanol twice, putting the bacterial cellulose into the prepared isopropanol aqueous solution, magnetically stirring the bacterial cellulose for 0.5 hour, standing the bacterial cellulose for 3 days, and freeze-drying the bacterial cellulose; keeping the temperature of 500 ℃ for 6h under the air atmosphere to obtain three-dimensional TiO₂A nanotube;

step three, preparing S-TiO₂The composite material comprises the following components: dissolving a certain amount of elemental sulfur in a proper amount of carbon disulfide to obtain a solution A, and dissolving the three-dimensional TiO prepared in the step three₂Adding nanotube into the solution A, wherein the three-dimensional TiO is₂The mass ratio of the nanotube to the elemental sulfur is 1:3, the mixture is magnetically stirred until the carbon disulfide is completely volatilized to obtain a uniform mixture, the mixture is heated to 200 ℃ for 1h after being heated to 155 ℃ for 8h in the argon atmosphere, and S-TiO is obtained₂A composite material;

step four, mixing pyrrole, phytic acid and isopropanol according to a volume ratio of 1: 2: 50 to obtain a solution B; dissolving a proper amount of ammonium persulfate in deionized water, and preparing an ammonium persulfate aqueous solution with the molar concentration of 0.29 mmol/mL;

step five: the S-TiO prepared in the third step is mixed according to the mass-to-volume ratio of 1g/25mL₂Adding the composite material into the solution B, stirring for 0.5h to obtain a solution C, then putting the solution C and an ammonium persulfate aqueous solution into an ice water bath for 0.5h, taking out, immediately and slowly adding the ammonium persulfate aqueous solution into the solution C under the condition of magnetic stirring according to the volume ratio of 1mL:2mL, reacting for 0.5h under the condition of magnetic stirring, filtering, and carrying out heat preservation and drying at 65 ℃ to obtain the sulfur-titanium dioxide-polypyrrole composite material.

2. The method for preparing the high sulfur-carrying capacity electrode material, i.e., the sulfur-titanium dioxide-polypyrrole according to claim 1, wherein the volume ratio of the isopropanol to the butyl titanate is adjusted in the first step, so that the prepared tube wall has a diameter of 8-50 nmThree-dimensional TiO₂A nanotube.

Technical Field

The invention relates to the technical field of preparation of electrode materials with high sulfur loading.

Background

Lithium Sulfur Battery (LSB) with high specific capacity (-1675 mAh g)^-1，～3500mA h cm^-3) High energy density (2.6kW h kg)^-1) Low cost, environmental protection, rich resources and the like, and is concerned by the majority of scientific researchers. However, LSB also has significant disadvantages: polysulfide of a reaction intermediate is easily dissolved in organic electrolyte, so that the capacity of the battery is rapidly attenuated, and even the battery fails; the volume change of sulfur is large (80%), and the falling failure of the anode powder is easily caused. Appropriate measures are taken to address the problems faced by LSB which require that the positive electrode carrier be loaded with as much sulphur as possible, effectively adsorb polysulphides to inhibit their dissolution and shuttling effects, and be able to buffer volumetric changes in sulphur during cycling. TiO 2₂The sulfur carrier material has the advantages of strong chemical adsorption capacity, low cost and the like, so the sulfur carrier material is a sulfur carrier material which is concerned. Preparation of TiO with both ultra-high specific surface area and ultra-high pore volume₂The carrier can fully exert the advantages of the structural characteristics and the chemical components, the carrier can be used for inhibiting the dissolution and the shuttling effect of polysulfide in a physical and chemical dual mode by virtue of the ultrahigh specific surface area, large pore volume, high sulfur loading amount, complex hierarchical pore structure and the characteristic of chemical lithium polysulfide affinity, and the volume change of sulfur in the process of buffering circulation is buffered, and the polypyrrole coating layer is formed on the surface of the electrode material, so that the conductivity of the electrode can be improved, meanwhile, it can adsorb polysulfide in a physical and chemical dual mode, inhibit the dissolution and shuttle effects of the polysulfide, however, in the prior researches, how to prepare the sulfur carrier material with ultrahigh specific surface area and ultrahigh pore volume is not particularly mature, therefore, the preparation of the sulfur carrier material with ultrahigh specific surface area and ultrahigh pore volume by using BC as a template becomes a trend and hot spot of future technical development.

Disclosure of Invention

Aiming at the prior art, the invention provides a method for preparing a high-sulfur-carrying-capacity electrode material sulfur-titanium dioxide-polypyrrole (S-TiO)₂-PPy). The invention selects bacteriaCellulose (BC) is used as a template, and TiO with a certain thickness is covered on the surface of the template₂Then removing BC through sintering to obtain three-dimensional TiO₂Nanotubes, into which elemental sulphur is subsequently injected to give S-TiO₂Then on S-TiO₂Coating a layer of PPy on the surface to obtain S-TiO₂-PPy electrode material. By adjusting the volume ratio of isopropanol to butyl titanate, three-dimensional TiO with different pipe diameters and wall thicknesses is obtained₂Nanotube to obtain S-TiO with different forms₂-PPy electrode material. The invention realizes controllable preparation of three-dimensional TiO by using BC₂The nanotube realizes the rapid synthesis of the electrode material with high sulfur carrying capacity, is environment-friendly, and avoids the long preparation time and the loss of expensive equipment and experimental consumables.

In order to solve the technical problems, the invention provides a method for preparing a high-sulfur-carrying-capacity electrode material sulfur-titanium dioxide-polypyrrole, which comprises the following steps:

step one, preparing bacterial cellulose aerogel: mixing isopropanol and butyl titanate according to the volume ratio of 100mL: 3-7 mL, stirring the mixture by using magnetons to form a uniform mixed solution, and then soaking the bacterial cellulose cut into small pieces in the mixed solution for 2 days to obtain the bacterial cellulose aerogel;

step two, preparing three-dimensional TiO₂Nanotube: mixing isopropanol and water according to the volume ratio of 9:1, stirring the mixture by using magnetons to form a uniform isopropanol aqueous solution, quickly washing the bacterial cellulose soaked in the step one by using isopropanol twice, putting the bacterial cellulose into the prepared isopropanol aqueous solution, magnetically stirring the bacterial cellulose for 0.5 hour, standing the bacterial cellulose for 3 days, and freeze-drying the bacterial cellulose; keeping the temperature of 500 ℃ for 6h under the air atmosphere to obtain three-dimensional TiO₂A nanotube;

step three, preparing S-TiO₂The composite material comprises the following components: dissolving a certain amount of elemental sulfur in a proper amount of carbon disulfide to obtain a solution A, and dissolving the three-dimensional TiO prepared in the step three₂Adding nanotube into the solution A, wherein the three-dimensional TiO is₂The mass ratio of the nanotube to the elemental sulfur is 1:3, the mixture is magnetically stirred until the carbon disulfide is completely volatilized to obtain a uniform mixture, the mixture is heated to 200 ℃ for 1h after being heated to 155 ℃ for 8h in the argon atmosphere, and S-TiO is obtained₂Composite material；

Step four, mixing pyrrole, phytic acid and isopropanol according to a volume ratio of 1: 2: 50 to obtain a solution B; dissolving a proper amount of ammonium persulfate in deionized water, and preparing an ammonium persulfate aqueous solution with the molar concentration of 0.29 mmol/mL;

step five: the S-TiO prepared in the third step is mixed according to the mass-to-volume ratio of 1g/25mL₂Adding the composite material into the solution B, stirring for 0.5h to obtain a solution C, then putting the solution C and an ammonium persulfate aqueous solution into an ice water bath for 0.5h, taking out, immediately and slowly adding the ammonium persulfate aqueous solution into the solution C under the condition of magnetic stirring according to the volume ratio of 1mL:2mL, reacting for 0.5h under the condition of magnetic stirring, filtering, and keeping the temperature at 65 ℃ and drying to obtain the S-TiO₂-a PPy composite.

In the first step of the preparation method, the volume ratio of isopropanol to butyl titanate is adjusted, so that the three-dimensional TiO with the pipe wall of 8-50 nm is prepared₂A nanotube.

Compared with the prior art, the invention has the beneficial effects that:

the preparation method realizes controllable preparation of the three-dimensional nanotube electrode material by simply controlling the proportion of each component in the solution, has the characteristics of simplicity, rapidness, good repeatability and the like, avoids the defects of complex preparation process, expensive equipment, low efficiency and the like, and has good application prospect in the aspect of preparing the three-dimensional nanotube/wire material with high specific surface area.

Drawings

FIG. 1 shows S-TiO obtained in example 1 (isopropyl alcohol: butyl titanate ═ 100:5) of the present invention₂-XRD pattern of PPy;

FIG. 2 shows S-TiO obtained in example 1 of the present invention₂-SEM picture of PPy;

FIG. 3 shows S-TiO obtained in example 1 of the present invention₂-a first charge-discharge diagram of PPy;

FIG. 4 shows S-TiO obtained in example 2 (isopropyl alcohol: butyl titanate ═ 100:3) of the present invention₂-XRD pattern of PPy;

FIG. 5 shows the S-TiO compound obtained in example 2 of the present invention₂-SEM picture of PPy;

FIG. 6 shows S-TiO obtained in example 2 of the present invention₂-a first charge-discharge diagram of PPy;

FIG. 7 shows S-TiO obtained in example 3 (isopropyl alcohol: butyl titanate ═ 100:7) of the present invention₂-XRD pattern of PPy;

FIG. 8 shows S-TiO obtained in example 3 of the present invention₂-SEM picture of PPy;

FIG. 9 shows S-TiO obtained in example 3 of the present invention₂-a first charge-discharge diagram of PPy;

Detailed Description

The invention will be further described with reference to the following figures and specific examples, which are not intended to limit the invention in any way.

The invention provides a method for preparing a high-sulfur-carrying-capacity electrode material sulfur-titanium dioxide-polypyrrole (S-TiO)₂-PPy) method, firstly preparing bacterial cellulose aerogel, then soaking it in isopropanol solution of butyl titanate, then placing the soaked bacterial cellulose in isopropanol aqueous solution, after the reaction is finished, freeze-drying sample, sintering so as to obtain three-dimensional TiO₂Nanotube and then three-dimensional TiO₂The nano tube is immersed into sulfur at 155 ℃ under argon atmosphere to obtain S-TiO₂The composite material is finally oxidized in S-TiO by ammonium persulfate in ice-water bath₂A layer of polypyrrole (PPy) film is synthesized on the surface of the composite material to form S-TiO₂-PPy electrode material. The invention successfully synthesizes the three-dimensional TiO by utilizing the biological material BC₂Nanotube, followed by synthesis of S-TiO with high sulfur loading₂The PPy electrode material avoids the problems of environmental pollution and the like caused by regulating and synthesizing by chemical reagents, and ensures that the material preparation has controllability.