CN116675185A - Ferrous diselenide rod-shaped nanoflower nitrogen-doped carbon material, and preparation method and application thereof - Google Patents

Ferrous diselenide rod-shaped nanoflower nitrogen-doped carbon material, and preparation method and application thereof Download PDF

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CN116675185A
CN116675185A CN202310681057.1A CN202310681057A CN116675185A CN 116675185 A CN116675185 A CN 116675185A CN 202310681057 A CN202310681057 A CN 202310681057A CN 116675185 A CN116675185 A CN 116675185A
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doped carbon
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fese
rod
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杨程凯
邹鹏坤
罗京
于岩
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Fuzhou University
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B19/00—Selenium; Tellurium; Compounds thereof
    • C01B19/007—Tellurides or selenides of metals
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
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    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
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    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
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    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/40—Electric properties
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y02E60/10—Energy storage using batteries

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Abstract

The invention provides a ferrous diselenide rod-shaped nano flower nitrogen-doped carbon material, and a preparation method and application thereof, and belongs to the technical field of battery materials. The method is characterized in that the prepared iron selenide is in a nano flower-shaped structure composed of nano rods, and the outer layer is coated by a nitrogen-doped carbon shell, so that the self-assembled nano flower composite material is provided. The nanometer flower-shaped structure increases the specific surface area of the material, provides rich active sites for catalysis, enhances the physical confinement of polysulfide and the transmission of electrons by the nitrogen-doped carbon shell, and is FeSe 2 The strong chemical bonding with polysulfide can effectively anchor polysulfide, and meanwhile, the catalytic conversion of polysulfide can be accelerated, and the shuttle effect is relieved. By using the methodThe lithium sulfur battery using the material as the positive electrode active material has excellent cycle stability and high sulfur carrying capacity.

Description

Ferrous diselenide rod-shaped nanoflower nitrogen-doped carbon material, and preparation method and application thereof
Technical Field
The invention relates to the technical field of battery materials, in particular to a ferrous diselenide rod-shaped nano flower nitrogen-doped carbon material, and a preparation method and application thereof.
Background
With the development of industry and society, human consumption of energy is continuously increased, and global problems such as greenhouse effect and air pollution are frequently caused. Therefore, a human needs to develop clean energy, and the clean energy is converted into stable and sustainable energy through an energy storage and conversion device due to instability, intermittence and other problems.
Lithium ion batteries are currently the most common commercial secondary batteries. However, the theoretical specific capacity of the lithium ion battery is generally not more than 300 mAh.g -1 With the continuous maturity of technology and technology, the specific capacity of lithium ion batteries is close to the theoretical limit, but still does not meet the industrial requirements, so that an electrochemical energy storage system with high specific energy, high safety coefficient and low cost needs to be developed. In contrast, lithium sulfur batteries are more advantageous in that their theoretical specific energy and specific capacity are 2600 Wh.kg, respectively -1 、1672mAh·g -1 The high specific capacity and energy density of lithium sulfur batteries show a broad application prospect, but at present, a plurality of problems and challenges still exist.
Shuttle effect: polysulfide shuttles during charge and discharge to form insulating product Li at the negative electrode 2 S, attaching the passivation film on the surface of the lithium sheet to form the passivation film. The substance attached to the lithium sheet during charging cannot return to the positive electrode to be converted into S 8 The loss of active material is thus irreversible, resulting in a decrease in battery capacity.
The elemental sulfur and the final discharge product have insulativity, so that the separation rate of electrons and ions is reduced, and the electrochemical reaction impedance is increased.
The sulfur has great volume change in the charge and discharge process, damages the structure of the battery, causes pulverization, increases the resistance inside the battery and deteriorates the cycle performance of the battery.
In order to solve the above problems, many researchers often use carbon materials as sulfur carriers to improve electronic conductivity, use porous structures of carbon and heteroatom doping as physical and chemical barriers to enhance adsorption of polysulfide, but anchoring of polysulfide alone does not well inhibit shuttling of polysulfide, and affects electrochemical reaction rate, reducing utilization of active substances.
Disclosure of Invention
The invention aims to provide a ferrous diselenide rod-shaped nanoflower nitrogen-doped carbon material, and a preparation method and application thereof, so as to solve the technical problems of poor electrochemical reaction performance and poor cycle performance of the conventional lithium-sulfur battery.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides FeSe 2 The preparation method of the rod-shaped nano flower nitrogen-doped carbon material comprises the following steps:
1) Mixing ferric ammonium sulfate, water and glucose to obtain a solution A;
2) Mixing the hydrazine hydrate solution and the selenium powder until the solution turns dark reddish brown to obtain a solution B;
3) Adding the solution B into the solution A for hydrothermal reaction to obtain a black powder sample;
4) Performing heat treatment on the black powder sample in a protective atmosphere to obtain FeSe 2 The rod-shaped nanoflower nitrogen-doped carbon material.
Further, the molar volume ratio of the ferric ammonium sulfate, the water and the glucose is 0.5-1.5 mmol: 15-25 mL: 3-5 mmol.
Further, the dosage ratio of the hydrazine hydrate solution to the selenium powder is 4-6 mL:1.0 to 3.0mmol, and the volume fraction of the hydrazine hydrate solution is 80 to 85 percent.
Further, the molar ratio of the ferric ammonium sulfate to the selenium powder is 0.5-1.5: 1.0 to 3.0.
Further, in the step 3), the temperature of the hydrothermal reaction is 160-200 ℃, and the time of the hydrothermal reaction is 8-12 h.
Further, in the step 4), the temperature of the heat treatment is 300-400 ℃, the heating rate is 10-20 ℃/min, and the time of the heat treatment is 2-3 h.
Further, in the step 4), the protective atmosphere is nitrogen, argon or helium.
The invention provides FeSe 2 The rod-shaped nanoflower nitrogen-doped carbon material.
The invention also provides FeSe 2 The application of the rod-shaped nanoflower nitrogen-doped carbon material in the lithium sulfur battery.
The invention has the beneficial effects that:
according to the invention, the nitrogen-doped rod-shaped nano flower carbon material is constructed by self-assembly, wherein the petal-shaped thin-layer carbon material structure can increase the specific surface area of the material, has the characteristics of high porosity and large specific surface area, can fully expose adsorption catalytic sites, is beneficial to uniform loading of nano selenide, fully contacts polysulfide, shortens an electron transfer path, and provides a physical barrier for polysulfide and a high-speed channel for electron conduction. Meanwhile, gaps among the nanoflower provide a rapid channel for ion transport, nitrogen doping converts nonpolar carbon materials into polar carbon materials, adsorption of polysulfide is converted from physical adsorption into chemical adsorption, the conversion energy barrier of polysulfide is reduced, and shuttle of polysulfide is relieved.
FeSe in the invention 2 There is a strong interaction with polysulfide, which has anchoring effect on polysulfide, and greatly reduces decomposition energy barrier of polysulfide, accelerates polysulfide conversion, and has dual synergistic effect of anchoring and accelerating catalytic polysulfide. Wherein the interaction of Fe-S bond and Se-Li bond provides multiple adsorption sites, and strong interaction exists between the Fe-S bond and the Se-Li bond, and the double adsorption sites can provide stronger polysulfide capturing capability.
Compared with the prior art, the FeSe of the invention 2 The rod-shaped nano flower nitrogen doped carbon material also has the following advantages:
1) FeSe of the invention 2 The rod-shaped nano flower nitrogen doped carbon material can realize double synergies of anchoring and catalysis, can obviously relieve shuttle of polysulfide in the battery cycle process, shows excellent long-cycle stability and rate capability, and improves the cycle life of a lithium-sulfur battery.
2) The nitrogen doped rod-shaped nano flower carbon material structure disclosed by the invention not only fully exposes adsorption catalytic sites and realizes uniform loading of a catalyst, but also provides a high-speed transmission channel for ions and electrons, and the adsorption of polysulfide is converted from physical adsorption to chemical adsorption so as to further relieve shuttle of polysulfide.
3) By FeSe 2 Catalytic properties of the catalyst on sulfides. The interaction of Fe-S bond and Se-Li bond provides multiple adsorption sites, greatly reduces the decomposition energy barrier of polysulfide, accelerates the conversion of polysulfide, and realizes double coordination of anchoring and catalysis.
Drawings
FIG. 1 is a FeSe prepared in example 1 2 Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) images of different magnifications of rod-shaped nanoflower nitrogen-doped carbon material, wherein (a) is FeSe 2 SEM image of @ NC, (b) enlarged SEM image, (c) low-power TEM, (d, e) enlarged TEM; (f) is a HTEM map;
FIG. 2 shows FeSe prepared in application example 1 2 Long cycle performance plot at 1C for NC/S;
FIG. 3 shows FeSe prepared in application example 1 2 100 cycles of the loop chart at 0.2C @ NC/S;
FIG. 4 is a 100-cycle chart at 0.2C for the SP/S prepared in comparative example 1;
FIG. 5 shows FeSe prepared in application example 1 2 A @ NC/S rate capability map;
FIG. 6 is a graph showing the rate performance of the SP/S prepared in comparative example 1.
Detailed Description
The invention provides FeSe 2 The preparation method of the rod-shaped nano flower nitrogen-doped carbon material comprises the following steps:
1) Mixing ferric ammonium sulfate, water and glucose to obtain a solution A;
2) Mixing the hydrazine hydrate solution and the selenium powder until the solution turns dark reddish brown to obtain a solution B;
3) Adding the solution B into the solution A for hydrothermal reaction to obtain a black powder sample;
4) Performing heat treatment on the black powder sample in a protective atmosphere to obtain FeSe 2 The rod-shaped nanoflower nitrogen-doped carbon material.
In the invention, the molar volume ratio of the ferric ammonium sulfate, the water and the glucose is 0.5-1.5 mmol: 15-25 mL:3 to 5mmol, preferably 0.8 to 1.2mmol: 18-22 mL:3.5 to 4.5mmol, more preferably 1.0mmol:20mL:4mmol.
In the invention, the dosage ratio of the hydrazine hydrate solution to the selenium powder is 4-6 mL:1.0 to 3.0mmol, preferably 5mL:2mmol.
In the present invention, the volume fraction of the hydrazine hydrate solution is 80 to 85%, preferably 85%.
In the invention, the molar ratio of the ferric ammonium sulfate to the selenium powder is 0.5-1.5: 1.0 to 3.0, preferably 0.8 to 1.2:1.6 to 2.4, more preferably 1.0:2.0.
in the present invention, in the step 3), the temperature of the hydrothermal reaction is 160 to 200 ℃, preferably 170 to 190 ℃, and more preferably 180 ℃; the hydrothermal reaction time is 8 to 12 hours, preferably 9 to 11 hours, and more preferably 10 hours.
In the present invention, in the step 4), the temperature of the heat treatment is 300 to 400 ℃, preferably 320 to 380 ℃, and more preferably 350 ℃; the heating rate is 10-20 ℃/min, preferably 12-18 ℃/min, and more preferably 15 ℃/min; the heat treatment time is 2 to 3 hours, preferably 2.5 hours.
In the present invention, in the step 4), the protective atmosphere is nitrogen, argon or helium, preferably nitrogen.
The invention provides FeSe 2 The rod-shaped nanoflower nitrogen-doped carbon material.
The invention also provides FeSe 2 The application of the rod-shaped nanoflower nitrogen-doped carbon material in the lithium sulfur battery.
The technical solutions provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of the present invention.
Example 1
FeSe 2 Preparing a rod-shaped nano flower nitrogen-doped carbon material:
firstly, 1mmol of ferric ammonium sulfate is weighed, dissolved in 20mL of deionized water, and 4mmol of glucose is added for stirringUntil completely dissolved, a solution A was obtained. And secondly, transferring 5mL of hydrazine hydrate solution (85%) into a beaker by using a pipetting gun, weighing 2mmol of selenium powder, slowly adding the selenium powder into the hydrazine hydrate solution, and stirring for 30min until the solution turns dark reddish brown, so as to prepare solution B. And thirdly, slowly dripping the solution B into the solution A, continuously stirring until the solution A is uniformly mixed, performing heat treatment for 10 hours at 160 ℃ by adopting a hydrothermal method, finally obtaining a black precipitate, washing and drying the black precipitate, and collecting a black powder sample. Fourthly, placing the black powder into a tube furnace, heating to 350 ℃ at a heating rate of 20 ℃/min under the protection of nitrogen, and keeping for 2 hours to finally obtain FeSe 2 Nitrogen-doped carbon material of rod-shaped nanoflower (FeSe) 2 @NC)。
Example 2
FeSe 2 Preparing a rod-shaped nano flower nitrogen-doped carbon material:
firstly, 1mmol of ferric ammonium sulfate is weighed and dissolved in 20mL of deionized water, and 3mmol of glucose is added and stirred until the solution is completely dissolved, so as to prepare solution A. And secondly, transferring 5mL of hydrazine hydrate solution (85%) into a beaker by using a pipetting gun, weighing 2mmol of selenium powder, slowly adding the selenium powder into the hydrazine hydrate solution, and stirring for 30min until the solution turns dark reddish brown, so as to prepare solution B. And thirdly, slowly dripping the solution B into the solution A, continuously stirring until the solution A is uniformly mixed, performing heat treatment for 8 hours at 180 ℃ by adopting a hydrothermal method, finally obtaining a black precipitate, washing and drying the black precipitate, and collecting a black powder sample. Fourthly, placing the black powder into a tube furnace, heating to 380 ℃ at a heating rate of 15 ℃/min under the protection of nitrogen, and keeping for 2 hours to finally obtain FeSe 2 Nitrogen-doped carbon material of rod-shaped nanoflower (FeSe) 2 @NC)。
Example 3
FeSe 2 Preparing a rod-shaped nano flower nitrogen-doped carbon material:
firstly, 1mmol of ferric ammonium sulfate is weighed and dissolved in 20mL of deionized water, and 5mmol of glucose is added and stirred until the solution is completely dissolved, so as to prepare solution A. And secondly, transferring 5mL of hydrazine hydrate solution (85%) into a beaker by using a pipetting gun, weighing 2mmol of selenium powder, slowly adding the selenium powder into the hydrazine hydrate solution, and stirring for 30min until the solution turns dark reddish brown, so as to prepare solution B. Thirdly, slowly dripping the solution B into the solution A, and continuously stirring untilMixing uniformly, performing heat treatment at 200 ℃ for 12 hours by adopting a hydrothermal method, finally obtaining black precipitate, washing, drying and collecting black powder samples. Fourthly, placing the black powder into a tube furnace, heating to 320 ℃ at a heating rate of 10 ℃/min under the protection of nitrogen, and keeping for 2 hours to finally obtain FeSe 2 Nitrogen-doped carbon material of rod-shaped nanoflower (FeSe) 2 @NC)。
Application example 1
Preparation of positive electrode active material of lithium-sulfur battery:
sublimed Sulfur and FeSe of example 1 2 @ NC is prepared from the following components in percentage by weight: 4 weighing and putting into a mortar to grind for 20min so as to uniformly mix the materials. Placing the mixed powder into a reaction kettle under the protection of argon, keeping the temperature at 155 ℃ for 12 hours, and naturally cooling to room temperature to obtain FeSe 2 The @ NC/S material was used as the positive electrode material.
Application example 2
Preparing a positive plate of the lithium-sulfur battery, assembling and testing a full battery of the lithium-sulfur battery.
Preparing a positive plate of the lithium-sulfur battery: taking the sulfur cathode material (FeSe) 2 @ NC/S) and conductive carbon black (SuperP), PVDF in sequence according to 8:1:1, adding an appropriate amount of NMP solution, mixing and stirring to obtain uniform slurry. And coating the uniformly mixed paste slurry on the surface of the aluminum foil of the current collector by using a scraper. Then transferring to a vacuum oven at 60 ℃ for 12 hours, drying, taking out, using a puncher to prepare a wafer with the diameter of 12mm as an anode, and preparing FeSe 2 @ C/S positive plate.
Comparative example 1
Preparation of conventional carbon black-sulfur positive electrode active material:
sublimated sulfur and Super-P (carbon black) in a weight ratio of 6:4 weighing and putting into a mortar to grind for 20min so as to uniformly mix the materials. And (3) placing the mixed powder into a reaction kettle under the protection of argon, keeping the temperature at 155 ℃ for 12 hours, and naturally cooling to room temperature to obtain the SP/S material serving as the anode material.
Comparative example 2
Preparing a positive plate of the lithium-sulfur battery: taking the sulfur positive electrode material (SP/S), conductive carbon black (SuperP) and PVDF according to the following sequence of 8:1:1, adding an appropriate amount of NMP solution, mixing and stirring to obtain uniform slurry. And coating the uniformly mixed paste slurry on the surface of the aluminum foil of the current collector by using a scraper. Then transferring to a vacuum oven for 12 hours at the constant temperature of 60 ℃, drying, taking out, and using a puncher to prepare a wafer with the diameter of 12mm as a positive electrode to prepare the SP/S positive electrode plate.
Full cell performance test was performed on the positive electrode sheets obtained in application example 2 and comparative example 2: the cycle performance and the multiplying power performance of the lithium sulfur battery are tested on a blue CT-2001A battery system, and the charging and discharging voltage ranges from 1.7V to 2.8V. The assembled lithium sulfur battery was subjected to 300 cycles of cycle performance test at 1C rate, 100 cycles of cycle performance test at 0.2C rate, and rate performance test at 0.2, 0.5, 1.0, 2.0, and 3.0C current densities, respectively.
FIG. 1 is FeSe of example 1 2 Scanning Electron Microscope (SEM) images and Transmission Electron Microscope (TEM) images of different magnifications of the rod-shaped nanoflower nitrogen-doped carbon material, the prepared iron selenide can be seen to present a nanoflower-shaped structure (a) consisting of nanorods, and FeSe is observed from a large-scale SEM image (b) 2 The size and distribution of the @ NC nanoflower are uniform. The nanorod diameter was measured in an enlarged SEM image to be around 40 nm. Further characterization of FeSe Using TEM 2 The microstructure of @ NC, as shown in fig. 1c, can be seen with the nanorods grown closely together, and after a magnification, the clear nanorods can be seen (see fig. 1 d), corresponding to the SEM image. The HTEM diagram is shown in fig. 1e, where the carbon shell encapsulates the iron selenide is clearly seen and the measured lattice is about 0.25nm.
FIG. 2 shows FeSe of example 1 at room temperature 2 The long cycle performance curve of the lithium sulfur battery assembled by taking the rod-shaped nano flower nitrogen-doped carbon material as an active material sulfur carrier is 300 circles under the multiplying power of 1C, and the capacity is still stable at 584.1 mAh.g after 300 circles of the lithium sulfur battery are cycled under the current density of 1C -1 The capacity retention rate was close to one hundred percent, confirming FeSe 2 Excellent cycling stability of NC/S electrodes.
FIG. 3 is a schematic diagram of application example 2 of FeSe according to the present invention 2 Rod-shaped nanoflower nitrogen-doped carbon material is taken as a carrier of active substance sulfur to jointly form a positive electrode material, and FIG. 4 shows that carbon black is taken as a sulfur carrier to jointly form the positive electrode materialAnd (5) material. The lithium sheet is used as the negative electrode of the lithium-sulfur battery, the same PP diaphragm is adopted to be assembled together into the lithium-sulfur full battery, and the lithium-sulfur full battery circulates for 100 circles under the multiplying power of 0.2 ℃. As can be seen, the initial capacity of the lithium sulfur battery assembled by the positive electrode sheet of application example 2 is 1223.4 mAh.g -1 After 100 circles, the capacity can still be kept at 1039.3 mAh.g -1 The corresponding capacity retention was 84.9%. While the discharge capacity of the lithium sulfur battery assembled by the positive plate of the comparative example 2 is only 912.4 mAh.g at the current density of 0.2C -1 After 100 circles, the capacity is 615.0 mAh.g -1 The capacity retention was only 67.4%. The comparison shows that the sulfur carrier has obvious improvement on the utilization rate and the cycle stability of active substances.
FIGS. 5 and 6 assembled into lithium-sulfur full cells by the same method as described above, and comparative study of FeSe 2 @ NC/S and SP/S ratio capability at different current densities. FeSe 2 Specific discharge capacities at 0.2, 0.5, 1.0, 2.0 and 3.0C current densities @ NC/S were 1122.0, 901.9, 899.7, 695.8 and 495.3 mAh.g, respectively -1 After circulation, the current density returns to 0.2C capacity again and can still be kept at 1017.0 mAh.g -1 . The specific capacity of SP/S is only 225.7 mAh.g under the current density of 3C -1 When the current density jumps back to 0.2C, the specific discharge capacity is only 668.7 mAh.g -1 . The rate performance results show that relative to SP, feSe 2 The @ NC is more beneficial to improving the multiplying power performance of the lithium-sulfur battery, which shows that FeSe 2 Excellent catalytic ability @ NC. The sulfur carrier carbon material disclosed by the invention can be predicted to have a certain quick charge capacity and a certain practical application value.
As can be seen from the above examples, the present invention provides a ferrous diselenide rod-shaped nanoflower nitrogen-doped carbon material, and a preparation method and application thereof. The iron selenide prepared by the method has a nano flower-shaped structure consisting of nano rods, and the outer layer is coated by a nitrogen-doped carbon shell, so that the iron selenide is a self-assembled nano flower composite material. The nanometer flower-shaped structure increases the specific surface area of the material, provides rich active sites for catalysis, enhances the physical confinement of polysulfide and the transmission of electrons by the nitrogen-doped carbon shell, and is FeSe 2 Has strong chemical bond with polysulfide and can effectively anchor polysulfideAnd meanwhile, the catalytic conversion of polysulfide can be accelerated, and the shuttle effect is relieved. The lithium sulfur battery adopting the material as the positive electrode active material has excellent cycle stability and high sulfur carrying capacity.
The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.

Claims (9)

1. FeSe 2 The preparation method of the rod-shaped nano flower nitrogen-doped carbon material is characterized by comprising the following steps of:
1) Mixing ferric ammonium sulfate, water and glucose to obtain a solution A;
2) Mixing the hydrazine hydrate solution and the selenium powder until the solution turns dark reddish brown to obtain a solution B;
3) Adding the solution B into the solution A for hydrothermal reaction to obtain a black powder sample;
4) Performing heat treatment on the black powder sample in a protective atmosphere to obtain FeSe 2 The rod-shaped nanoflower nitrogen-doped carbon material.
2. The preparation method according to claim 1, wherein the molar volume ratio of the ferric ammonium sulfate, the water and the glucose is 0.5-1.5 mmol: 15-25 mL: 3-5 mmol.
3. The preparation method according to claim 1 or 2, wherein the dosage ratio of the hydrazine hydrate solution to the selenium powder is 4-6 mL:1.0 to 3.0mmol, and the volume fraction of the hydrazine hydrate solution is 80 to 85 percent.
4. The preparation method according to claim 3, wherein the molar ratio of the ferric ammonium sulfate to the selenium powder is 0.5-1.5: 1.0 to 3.0.
5. The method according to claim 1, 2 or 4, wherein in the step 3), the hydrothermal reaction is performed at 160 to 200 ℃ for 8 to 12 hours.
6. The method according to claim 5, wherein in the step 4), the heat treatment is performed at a temperature of 300 to 400 ℃, a heating rate of 10 to 20 ℃/min, and a heat treatment time of 2 to 3 hours.
7. The method according to claim 1, 4 or 6, wherein in the step 4), the protective atmosphere is nitrogen, argon or helium.
8. FeSe prepared by the process of any one of claims 1 to 7 2 The rod-shaped nanoflower nitrogen-doped carbon material.
9. The FeSe of claim 8 2 The application of the rod-shaped nanoflower nitrogen-doped carbon material in the lithium sulfur battery.
CN202310681057.1A 2023-06-09 2023-06-09 Ferrous diselenide rod-shaped nanoflower nitrogen-doped carbon material, and preparation method and application thereof Pending CN116675185A (en)

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