A method for preparing nitrogen-doped porous carbon-coated metal selenide materials and their applications

Abstract

This invention discloses a method for preparing nitrogen-doped porous carbon-coated metal selenide materials and their applications. The preparation method includes the following steps: dissolving a metal salt in water to obtain a metal salt solution; adding a biomass precursor to the metal salt solution, soaking it at a constant temperature, then removing and drying it to obtain a biomass precursor with metal salt adhering to it; placing the biomass precursor with metal salt adhering to it and melamine in a tube furnace and annealing it under argon to obtain nitrogen-doped porous carbon-coated metal nanoparticle materials; mixing the nitrogen-doped porous carbon-coated metal nanoparticle materials with selenium powder evenly and annealing them under argon protection to obtain nitrogen-doped porous carbon-coated metal selenide materials. The nitrogen-doped porous carbon-coated metal selenide materials are used to prepare anode materials for sodium-ion batteries. The nitrogen-doped porous carbon-coated metal selenide materials prepared by this invention can improve the electrochemical performance of anode electrode materials for sodium-ion batteries.

Description

Technical Field

[0001] This invention relates to the field of micro / nano composite material synthesis technology, specifically to a method for preparing nitrogen-doped porous carbon-coated metal selenide materials and their applications. Background Technology

[0002] Sodium-ion batteries (SIBs) commonly use three main types of anode materials: intercalated anodes, alloy anodes, and conversion anodes. Conversion anodes (FeS2, CoSe2, Sn4P3, and Sb2O3) typically have a larger theoretical capacity than intercalated anodes and exhibit more moderate volume expansion than alloy anodes, resulting in superior overall performance. Discovered conversion anodes for SIBs mainly include metal oxides, metal phosphides, metal sulfides, and metal selenides. Compared to similar metal compounds, metal selenides, as anodes for SIBs, possess good reversibility and small volume change, exhibiting superior overall electrochemical performance. However, their conductivity is significantly lower than other traditional electrode materials. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing nitrogen-doped porous carbon-coated metal selenide materials and their applications, which can improve the electrochemical performance of sodium-ion battery anode electrode materials.

[0004] In one aspect of the present invention, a method for preparing nitrogen-doped porous carbon-coated metal selenide materials is provided. According to an embodiment of the present invention, the method includes the following steps:

[0005] (1) Dissolve the metal salt in water to obtain a metal salt solution, add the biomass precursor to the metal salt solution, keep it warm and soak it, then take it out and dry it to obtain a biomass precursor with metal salt attached.

[0006] (2) The biomass precursor with attached metal salt and melamine were placed in a tube furnace and annealed with argon to obtain nitrogen-doped porous carbon-coated metal nanoparticles.

[0007] (3) Nitrogen-doped porous carbon-coated metal nanoparticles are mixed evenly with selenium powder and then annealed under argon protection to obtain nitrogen-doped porous carbon-coated metal selenide materials.

[0008] In addition, the method for preparing a nitrogen-doped porous carbon-coated metal selenide material according to the above embodiments of the present invention may also have the following additional technical features:

[0009] In some embodiments of the present invention, in step (1), the concentration of the metal salt solution is 10-80 mmol·L. -1 The soaking temperature is 20-60℃, and the drying temperature is 50-60℃.

[0010] In some embodiments of the present invention, in step (1), the metal salt includes metal salts of Mn, Fe, Co, Ni, Cu, Zn, Sn or Bi.

[0011] In some embodiments of the present invention, in step (1), 1-5g of biomass precursor is soaked in 100ml of metal salt solution.

[0012] In some embodiments of the present invention, in step (1), the biomass precursor includes pomelo peel, pomelo pith, tangerine peel, tangerine pith, orange peel, orange pith, loofah pith, corn cob, or sesame stalk core.

[0013] In some embodiments of the present invention, in step (2), the mass ratio of the biomass precursor with attached metal salt to melamine is 0.5-1, the annealing temperature is 600-800℃, the holding time is 1-3h, and the heating rate is 1-10℃·min. -1 .

[0014] In some embodiments of the present invention, in step (3), the mass ratio of nitrogen-doped porous carbon-coated metal nanoparticles to selenium powder is 1:1, the annealing temperature is 400-500℃, the holding time is 1-3h, and the heating rate is 1-10℃·min. -1 .

[0015] In another aspect of the present invention, the present invention provides a nitrogen-doped porous carbon-coated metal selenide material prepared according to the preparation method of the nitrogen-doped porous carbon-coated metal selenide material described above.

[0016] In another aspect of the present invention, the present invention proposes the use of a nitrogen-doped porous carbon-coated metal selenide material, wherein, according to an embodiment of the present invention, the nitrogen-doped porous carbon-coated metal selenide material is used to prepare a negative electrode material for sodium-ion batteries.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1) The nitrogen-doped porous carbon-coated metal selenide material prepared by this invention provides more sodium storage sites, while also forming a large number of crystal defects, providing more active sites, improving the electronic conductivity of the metallide, and further enhancing the capacity and rate performance of the metal selenide as a negative electrode of sodium-ion batteries.

[0019] 2) This invention further expands the application scenarios of biomass in the energy field, utilizing the fluffy and porous characteristics of biomass to make it an excellent carrier in experimental schemes such as adsorption and loading.

[0020] 3) The method for preparing nitrogen-doped porous carbon-coated metal selenide materials provided by the present invention has universality and is applicable to the treatment of almost all biomass precursors and metal selenides. Attached Figure Description

[0021] Figure 1 These are high-magnification (a) and low-magnification (b) FESEM images of the nitrogen-doped porous carbon-coated cobalt nanoparticle material prepared in Example 1 of this invention.

[0022] Figure 2 The XRD diffraction pattern of the nitrogen-doped porous carbon-coated cobalt nanoparticle material prepared in Example 1 of this invention;

[0023] Figure 3 High-magnification (a) and low-magnification (b) FESEM images of nitrogen-doped porous carbon-coated nickel nanoparticles prepared in Example 2 of this invention;

[0024] Figure 4 The XRD diffraction pattern of the nitrogen-doped porous carbon-coated nickel nanoparticle material prepared in Example 2 of this invention;

[0025] Figure 5 These are high-magnification (a) and low-magnification (b) FESEM images of the nitrogen-doped porous carbon-coated cobalt nanoparticle material prepared in Example 3 of this invention.

[0026] Figure 6 The XRD diffraction pattern of the nitrogen-doped porous carbon-coated cobalt nanoparticle material prepared in Example 3 of this invention;

[0027] Figure 7 High-magnification (a) and low-magnification (b) FESEM images of the nitrogen-doped porous carbon-coated cobalt selenide material prepared in Example 4 of this invention;

[0028] Figure 8 The XRD diffraction pattern of the nitrogen-doped porous carbon-coated cobalt selenide material prepared in Example 4 of this invention;

[0029] Figure 9 The image shows the electrochemical performance of the sodium-ion battery prepared in Example 5 of this invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1

[0032] A method for preparing nitrogen-doped porous carbon-coated cobalt nanoparticles (using pomelo seeds as a precursor and Co metal salt) includes the following steps:

[0033] (1) Add 8 mmol of cobalt nitrate to 100 mL of deionized water and dissolve by sonication. Then add 2 g of grapefruit pith obtained by removing the yellow peel as a precursor to the cobalt nitrate solution, soak at 60°C for 24 h, then take it out and dry it in a 60°C forced-air drying oven to obtain grapefruit pith precursor with cobalt nitrate attached.

[0034] (2) 1.0 g of melamine was placed upstream of a tube furnace, and 500 mg of grapefruit pod precursor with cobalt nitrate attached was placed downstream of the tube furnace. After argon annealing, nitrogen-doped porous carbon-coated cobalt nanoparticles were obtained. The annealing temperature was 700 °C, the holding time was 2 h, and the heating rate was 2 °C·min. -1 .

[0035] like Figure 1-2 As shown, cobalt and nitrogen combine to catalyze a considerable number of carbon nanotubes on the porous carbon surface, and the cobalt nanoparticles are clearly and uniformly dispersed on the porous carbon matrix. XRD patterns show that the prepared nitrogen-doped porous carbon-coated cobalt nanoparticle material has a distinct cobalt peak and no other impurity peaks.

[0036] Example 2

[0037] A method for preparing nitrogen-doped porous carbon-coated nickel nanoparticles (using grapefruit pods as a precursor and Ni metal salt) includes the following steps:

[0038] (1) Add 8 mmol of nickel nitrate to 100 mL of deionized water and dissolve by sonication. Then add 2 g of grapefruit pith obtained by removing the yellow peel as a precursor to the nickel nitrate solution and soak at 60°C for 24 h. Then take it out and dry it in a 60°C forced-air drying oven to obtain grapefruit pith precursor with nickel nitrate attached.

[0039] (2) 1.0 g of melamine was placed upstream of a tube furnace, and 500 mg of grapefruit pod precursor with nickel nitrate attached was placed downstream of the tube furnace. After argon annealing, nitrogen-doped porous carbon-coated nickel nanoparticles were obtained. The annealing temperature was 700 °C, the holding time was 2 h, and the heating rate was 2 °C·min. -1 .

[0040] like Figure 3-4 As shown, nickel and nitrogen bind to the porous carbon surface, catalyzing the formation of a considerable number of carbon nanotubes. Furthermore, the uniform dispersion of nickel nanoparticles on the porous carbon matrix is ​​clearly visible. XRD patterns reveal that the prepared nitrogen-doped porous carbon-coated nickel nanoparticle material exhibits a distinct nickel peak and lacks other impurity peaks.

[0041] Example 3

[0042] A method for preparing nitrogen-doped porous carbon-coated cobalt nanoparticles (using orange pith as a precursor and Ni metal salt) includes the following steps:

[0043] (1) Add 8 mmol of cobalt nitrate to 100 mL of deionized water and dissolve by sonication. Then add 2 g of orange pith obtained by removing the orange peel as a precursor to the cobalt nitrate solution and soak at 60°C for 24 h. Then take it out and dry it in a 60°C forced-air drying oven to obtain orange pith precursor with cobalt nitrate attached.

[0044] (2) 1.0 g of melamine was placed upstream of a tube furnace, and 500 mg of orange pith precursor with cobalt nitrate attached was placed downstream of the tube furnace. After argon annealing, nitrogen-doped porous carbon-coated cobalt nanoparticles were obtained. The annealing temperature was 700 °C, the holding time was 2 h, and the heating rate was 2 °C·min. -1 .

[0045] like Figure 5-6 As shown, cobalt and nitrogen combine to catalyze a considerable number of carbon nanotubes on the porous carbon surface, and the cobalt nanoparticles are clearly and uniformly dispersed on the porous carbon matrix. XRD patterns show that the prepared nitrogen-doped porous carbon-coated cobalt nanoparticle material has a distinct cobalt peak and no other impurity peaks.

[0046] Example 4

[0047] A method for preparing nitrogen-doped porous carbon-coated metal selenide materials includes the following steps:

[0048] The nitrogen-doped porous carbon-coated metal nanoparticles prepared in Example 1 and selenium powder were mixed evenly at a mass ratio of 1:1 and then annealed at 400°C under argon protection to obtain nitrogen-doped porous carbon-coated metal selenide materials. The annealing temperature was 400°C, the holding time was 2 hours, and the heating rate was 2°C·min. -1 .

[0049] like Figure 7 As shown, a large number of dispersed cobalt selenide nanoparticles are embedded in a porous carbon matrix, and the cobalt selenide particles are slightly larger in size than cobalt nanoparticles. Figure 8 As shown, nitrogen-doped porous carbon-coated metal selenide materials exhibit obvious cobalt selenide diffraction peaks and have no other impurity peaks.

[0050] Example 5

[0051] The negative electrode material for sodium-ion batteries includes the following steps:

[0052] The nitrogen-doped porous carbon-coated metal selenide material prepared in Example 2 was uniformly mixed and dispersed with conductive carbon black and PVDF at a mass ratio of 8:1:1 in 400 μL of 1-methyl-2-pyrrolidone (NMP) to form a slurry.

[0053] The performance testing of the negative electrode material for sodium-ion batteries includes the following steps:

[0054] Sodium-ion battery negative electrode material slurry was uniformly coated onto a copper foil current collector using a 250μm scraper and dried in a 60℃ vacuum drying oven for 24 hours. The dried copper foil current collector was sliced ​​to form a 1.1cm diameter circular electrode. A sodium foil sheet was used as the counter electrode, glass fiber as the separator, and a binary electrolyte. A 2032 button half-cell was assembled in an argon-filled glove box. The test voltage range was 0.5V-3V vs. Na. + / Na.

[0055] like Figure 9 As shown, nitrogen-doped porous carbon-coated metal selenide materials exhibit excellent sodium storage performance.

[0056] The above embodiments are typical examples of the present invention and are not intended to limit the invention in any way. For example, the reaction concentration, reaction time, water bath temperature, annealing temperature, biomass type, and metal salt type can all be further adjusted. Therefore, based on the overall concept of the present invention, any adjustments or modifications to the process parameters described by those skilled in the art, as long as they do not deviate from the inventive concept or exceed the scope defined in the claims, should fall within the protection scope of the present invention.

Claims

1. A method for preparing a nitrogen-doped porous carbon-coated metal selenide material, characterized in that, Includes the following steps: (1) Dissolve the metal salt in water to obtain a metal salt solution, add the biomass precursor to the metal salt solution, keep it warm and soak it, then take it out and dry it to obtain a biomass precursor with metal salt attached. The metal salt includes metal salts of Mn, Fe, Co, Ni, Cu, Zn, Sn or Bi. (2) The biomass precursor with attached metal salt and melamine were placed in a tube furnace and annealed with argon to obtain nitrogen-doped porous carbon-coated metal nanoparticles, wherein the mass ratio of the biomass precursor with attached metal salt to melamine was 0.5-1. (3) After mixing nitrogen-doped porous carbon-coated metal nanoparticles with selenium powder evenly, nitrogen-doped porous carbon-coated metal selenide materials are obtained by annealing under argon protection.

2. The method for preparing a nitrogen-doped porous carbon-coated metal selenide material according to claim 1, characterized in that: In step (1), the concentration of the metal salt solution is 10-80 mmol·L⁻¹. -1 The soaking temperature is 20-60℃, and the drying temperature is 50-60℃.

3. The method for preparing a nitrogen-doped porous carbon-coated metal selenide material according to claim 1, characterized in that: In step (1), 1-5g of biomass precursor is soaked in 100ml of metal salt solution.

4. The method for preparing a nitrogen-doped porous carbon-coated metal selenide material according to claim 1, characterized in that: In step (1), the biomass precursors include pomelo peel, pomelo pith, tangerine peel, tangerine pith, orange peel, orange pith, orange pith, loofah pith, corn cob, or sesame stalk core.

5. The method for preparing a nitrogen-doped porous carbon-coated metal selenide material according to claim 1, characterized in that: In step (2), the annealing temperature is 600-800℃, the holding time is 1-3h, and the heating rate is 1-10℃·min. -1 .

6. The method for preparing a nitrogen-doped porous carbon-coated metal selenide material according to claim 1, characterized in that: In step (3), the mass ratio of nitrogen-doped porous carbon-coated metal nanoparticles to selenium powder is 1:1, the annealing temperature is 400-500℃, the holding time is 1-3h, and the heating rate is 1-10℃·min. -1 .

7. A nitrogen-doped porous carbon-coated metal selenide material prepared by a method according to any one of claims 1-6.

8. The use of the nitrogen-doped porous carbon-coated metal selenide material according to claim 7, characterized in that: The nitrogen-doped porous carbon-coated metal selenide material is used to prepare the negative electrode material for sodium-ion batteries.

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