Method for preparing transition metal disulfide / carbon-supported metal single atom superstructure material

Abstract

The present invention belongs to the technical field of electrochemical energy conversion and storage electrode materials, and specifically relates to a method for preparing a transition metal disulfide / carbon-loaded metal single-atom superstructure material. The method uses common transition metal inorganic salts and chalcogen sources as raw materials and common organic matter as a carbon source to synthesize a precursor by a solvent thermal method, and then obtains artificially controlled transition metal disulfide / carbon-loaded transition metal single-atom superstructure nanosheets with a periodic stacking structure through amide reaction, metal ion induction, and calcination. The superstructure nanosheets have a unique MS2 / C-SAY interface that can significantly improve interfacial electron transport and ion diffusion. In addition, the MS2 layer and the C-SAY layer are alternately stacked to achieve 100% surface contact between the MS2 layer and the C-SAY layer, greatly improving the electrochemical stability and reactivity of the MS2.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemical energy conversion and storage electrode materials, and specifically relates to a method for preparing a transition metal disulfide / carbon-loaded metal single atom superstructure material. Background Art

[0002] Lithium-ion batteries (LIBs) are widely used in electronic devices, electric vehicles, and large-scale energy storage due to their high energy density, long cycle life, and low self-discharge. Their primary cathode and anode materials are transition metal oxide lithium salts and graphite, respectively. However, the low abundance of resources such as lithium and cobalt has led to a supply shortage, rising prices, and a high reliance on imports in my country, posing a serious threat to the security of the LIB industry chain. Therefore, developing next-generation, lithium-free, high-energy-density, low-cost electrochemical energy storage devices and actively cultivating new production capacity are research hotspots to promote high-quality development in the electrochemical energy storage field. Currently, sodium-ion batteries (SIBs) stand out among many next-generation electrochemical energy storage technologies due to their high abundance, low cost, and similar physical and chemical properties to lithium. However, the electrochemical performance of SIBs is limited by the choice and design of the anode material. Transition metal disulfides (MS2) have been proposed due to their low cost, low ion diffusion resistance, short diffusion pathways, and large theoretical storage capacity. However, when MS2 undergoes a conversion reaction during discharge, the two-dimensional structure breaks down to form Na2S and transition metals. During charging, the segregation of these two elements and the high energy barrier for Na2S decomposition lead to irreversible conversion reactions, causing rapid degradation of the battery's electrochemical performance and even failure. Therefore, designing material structures to achieve highly reversible conversion of electrode materials has become a key issue in the development of sodium-ion batteries.

[0003] Currently, some researchers have combined transition metal disulfides with carbon materials to form composite materials. This introduces an MS2 / C interface to enhance the conductivity and structural stability of the material. However, the fundamental problem remains: how to lower the decomposition energy barrier for discharge products and achieve ideal electrochemical performance. Therefore, researchers have introduced single atoms into the interface, forming an MS2 / C-SAY interface, where the single atoms act as catalysts for the discharge products. However, the MS2 / C-SAY composites reported so far typically use C-SAY as a template, prepared via a solvothermal method with a few layers of MS2 loaded onto the C-SAY structure. This structure consists of an MS2 / C-SAY and MS2 / MS2 interface. While the reaction kinetics of MS2 in contact with C-SAY are significantly improved, the MS2 / MS2 interface not in contact with C-SAY still suffers from irreversible transformation, resulting in weak reaction kinetics and poor electrochemical performance. Therefore, the preparation of composite materials composed of 100% MS2 / C-SAY interfaces is key to achieving highly reversible sodium-ion batteries. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing a transition metal disulfide / carbon-supported metal single atom superstructure.

[0005] In order to achieve the purpose of the present invention, we will adopt the following technical solutions to implement it.

[0006] A method for preparing a transition metal disulfide / carbon-supported metal single atom superstructure material comprises the following steps:

[0007] S1. Dissolving a transition metal inorganic salt as a transition metal disulfide, a sulfur source, and an organic matter as a carbon source in a mixture of deionized water and anhydrous ethanol to obtain a mixed solution A, adjusting the pH value of the mixed solution A to 1-2, and synthesizing a precursor B having a preliminary layered structure by a hot solvent method;

[0008] S2, drying and recrystallizing the precursor B obtained by the hot solvent method to obtain a mixed powder C;

[0009] S3, dissolving an appropriate amount of mixed powder C and an organic substance providing anchoring sites in a buffer system to obtain a mixed solution D;

[0010] S4, drying and crystallizing the mixed solution D to obtain a powder sample E;

[0011] S5, dissolving the powder sample E and the metal inorganic salt providing metal ions in a buffer system to obtain a mixed solution F;

[0012] S6, drying and recrystallizing the mixed solution F to obtain a mixed powder G;

[0013] S7. Place the mixed powder G in a tube furnace and keep it at 750-800°C for 1-3 hours in a 5% hydrogen, 95% argon environment to obtain a powder sample H, which is the superstructure material; wherein:

[0014] The superstructure material is a superstructure nanosheet, and the expression of the superstructure nanosheet is MS2 / C-SAY SL, where MS2 is a transition metal disulfide, C is carbon, SAY is a single transition metal atom, and SL is a superstructure; the MS2 / C-SAY is a periodically arranged superstructure catalytic interface formed by alternating stacking of MS2 layers and C-SAY layers, wherein the MS2 layer is in 100% surface contact with the C-SAY layer.

[0015] Preferably, the transition metal inorganic salt is one or more of a water-soluble molybdenum salt or a water-soluble molybdate, a water-soluble tungsten salt or a water-soluble tungstate, and a water-soluble tin salt.

[0016] Preferably, the water-soluble molybdate includes ammonium molybdate and sodium molybdate; the water-soluble tungstate includes ammonium tungstate, sodium tungstate and paratungstate; and the water-soluble tin salt includes tin chloride and stannous chloride.

[0017] Preferably, the sulfur-containing source substance is one or more of thiourea, sodium thiosulfate, urea, thioacetamide, L-cysteine, tetrathiomolybdate, sodium sulfide, potassium sulfide, thiomalic acid, ammonium sulfide, and ammonium hydrogen sulfide.

[0018] Preferably, the carbon source is one or more of octylamine, oleic acid, sodium oleate, glucose, glycerol, ethylenediamine, polyethylene compound, polyvinyl alcohol, and dopamine.

[0019] Preferably, the organic matter providing the anchoring site is one or more of dopamine, carbamate, vinylamide, aminophenol-formaldehyde resin, and carbamic acid amide.

[0020] Preferably, the metal inorganic salt providing metal ions is water-soluble chromium salt or water-soluble chromate, water-soluble manganese salt or water-soluble manganate or water-soluble permanganate, water-soluble iron salt, water-soluble cobalt salt, water-soluble nickel salt, water-soluble copper salt, water-soluble zinc salt and water-soluble niobium salt.

[0021] Preferably, the water-soluble chromium salt or water-soluble chromate includes chromium nitrate, chromium perchlorate, chromium sulfate, chromium chloride, such as sodium chromate and potassium chromate; the water-soluble manganese salt or water-soluble manganate or water-soluble permanganate includes manganese sulfate, manganese nitrate, manganese chloride, manganese acetate, potassium manganate and potassium permanganate; the water-soluble iron salt includes ferric nitrate, ferric chloride, ferric citrate, ferric acetate, ferrous nitrate, ferrous chloride, ferric sulfate and ferrous sulfate; the water-soluble cobalt salt includes cobalt sulfate, cobalt nitrate, cobalt chloride, cobalt acetate and cobalt citrate; the water-soluble nickel salt includes nickel sulfate, nickel nitrate, nickel chloride, nickel acetate and nickel citrate; the water-soluble copper salt includes copper nitrate, copper sulfate, copper chloride, copper acetate and copper citrate; the water-soluble zinc salt includes zinc chloride, zinc sulfate, zinc nitrate, zinc fluoroborate, zinc gluconate and zinc acetate; the water-soluble niobium salt includes ammonium niobium oxalate and niobium pentachloride.

[0022] Preferably, the drying and recrystallization method is one of heat drying, freeze drying, and spray drying. Beneficial effects

[0023] The present invention relates to a transition metal disulfide / carbon-supported metal single atom superstructure material, which is a superstructured nanosheet with a unique MS2 / C-SAY catalytic interface. The MS2 layer and the C-SAY layer are periodically and alternately stacked, achieving 100% surface contact between the MS2 layer and the C-SAY layer. This results in the MS2 / C-SAY SL exhibiting excellent reaction kinetics and electrochemical performance.

[0024] The present invention uses common transition metal inorganic salts and chalcogen sources as raw materials and common organic matter as carbon source to synthesize precursors through a hot solvent method. The precursors are subjected to amide reaction, metal ion induction, and calcination to obtain artificially controlled transition metal disulfide / carbon-supported transition metal single-atom superstructure nanosheets with a periodic stacking structure.

[0025] The preparation process can obtain different types of transition metal disulfides and metal single atoms by using different types of transition metal inorganic salts. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a SEM photograph of the MoS2 / C-SACo SL material prepared in Example 1;

[0027] Figure 2 This is an AC-TEM photograph of the MoS2 / C-SACo SL material prepared in Example 1;

[0028] Figure 3 TEM photographs and measured lattice spacing diagrams of the MoS2 / C-SACo SL material prepared in Example 1;

[0029] Figure 4 XRD pattern of the MoS2 / C-SACo SL material prepared in Example 1;

[0030] Figure 5 This is a rate performance diagram of the MoS2 / C-SACo SL material prepared in Example 1 as a negative electrode for sodium ion batteries;

[0031] Figure 6 This is the cycling performance diagram of the MoS2 / C-SACo SL material prepared in Example 1 as the negative electrode of sodium ion battery. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings:

[0033] As embodiment 1 of the present invention, Figure 1-6 As shown, a method for preparing a transition metal disulfide / carbon-supported metal single atom superstructure material comprises the following steps:

[0034] 1) Weigh 1.6 g of sodium oleate, 1.0 g of sodium molybdate, and 0.9 g of thiourea, dissolve in 15 mL of deionized water, 15 mL of anhydrous ethanol, and 2 mL of oleic acid. Stir thoroughly until completely dissolved, and adjust the solution pH to 1 to obtain a mixed solution A. Precursor B with a preliminary layered structure is synthesized using a hot solvent method.

[0035] 2) Drying and recrystallizing the precursor B obtained by the solvent method to obtain mixed powder C (MoS2 / OA);

[0036] 3) Add an appropriate amount of precursor powder C, 244 mg of tris(hydroxymethyl)aminomethane, and 200 mg of dopamine hydrochloride to 200 ml of deionized water and stir for 24 hours to obtain a mixed solution D.

[0037] 4) Centrifuge four times and dry at 60°C for 12 h to obtain powder sample E (MoS2 / OA-PDA);

[0038] 5) Add powder E and 0.0238 g of cobalt chloride hexahydrate to 200 ml of deionized water, and stir at 100 rpm for 12 h at 30°C to obtain a mixed solution F.

[0039] 6) Drying and recrystallizing the mixed solution F to obtain mixed powder G (MoS2 / OA-PDA-Co);

[0040] 7) Powder G was kept at 750°C for 2 h in a 5% hydrogen, 95% argon environment to obtain MoS2 / C-SACo SL material.

[0041] As embodiment 2 of the present invention, Figure 1-6 As shown, a method for preparing a transition metal disulfide / carbon-supported metal single atom superstructure material comprises the following steps:

[0042] 1) Weigh 1.6 g of sodium oleate, 1.22 g of sodium tungstate, and 0.9 g of thiourea, dissolve them in 15 mL of deionized water, 15 mL of anhydrous ethanol, and 2 mL of oleic acid. Stir thoroughly until completely dissolved, and adjust the solution pH to 1 to obtain a mixed solution A. Precursor B with a preliminary layered structure is synthesized using a hot solvent method.

[0043] 2) Dry and recrystallize the precursor B obtained by the solvent method to obtain mixed powder C (WS2 / OA);

[0044] 3) Add an appropriate amount of precursor powder C, 244 mg of tris(hydroxymethyl)aminomethane, and 200 mg of dopamine hydrochloride to 200 ml of deionized water and stir for 24 hours to obtain a mixed solution D.

[0045] 4) Centrifuge four times and dry at 60°C for 12 h to obtain powder sample E (WS2 / OA-PDA);

[0046] 5) Add powder E and 0.0258 g of ferric chloride to 200 ml of deionized water, stir at 100 rpm and 30°C for 12 h to obtain a mixed solution F.

[0047] 6) Drying and recrystallizing the mixed solution F to obtain mixed powder G (WS2 / OA-PDA-Fe);

[0048] 7) Powder G was kept at 750°C for 2 h in a 5% hydrogen, 95% argon environment to obtain WS2 / C-SAFe SL material.

[0049] As embodiment 3 of the present invention, Figure 1-6 As shown, a method for preparing a transition metal disulfide / carbon-supported metal single atom superstructure material comprises the following steps:

[0050] 1) Weigh 1.6 g of sodium oleate, 1.12 g of ammonium perrhenate, and 0.9 g of thiourea, dissolve them in 15 mL of deionized water, 15 mL of anhydrous ethanol, and 2 mL of oleic acid. Stir thoroughly until completely dissolved, and adjust the solution pH to 1 to obtain a mixed solution A. Precursor B with a preliminary layered structure is synthesized using a hot solvent method.

[0051] 2) Dry and recrystallize the precursor B obtained by the solvent method to obtain mixed powder C (ReS2 / OA);

[0052] 3) Add an appropriate amount of precursor powder C, 244 mg of tris(hydroxymethyl)aminomethane, and 200 mg of dopamine hydrochloride to 200 ml of deionized water and stir for 24 hours to obtain a mixed solution D.

[0053] 4) Centrifuge four times and dry at 60°C for 12 h to obtain powder sample E (ReS2 / OA-PDA);

[0054] 5) Add powder E and 0.0238 g of cobalt chloride hexahydrate to 200 ml of deionized water, and stir at 100 rpm for 12 h at 30°C to obtain a mixed solution F.

[0055] 6) Drying and recrystallizing the mixed solution F to obtain mixed powder G (ReS2 / OA-PDA-Co);

[0056] 7) Powder G was kept in a 5% hydrogen, 95% argon environment at 750-800°C for 2 h to obtain ReS2 / C-SACo SL material.

[0057] As embodiment 4 of the present invention, Figure 1-6 As shown, a method for preparing a transition metal disulfide / carbon-supported metal single atom superstructure material comprises the following steps:

[0058] 1) Weigh 1.0 g of sodium molybdate and 0.9 g of thiourea and dissolve them in 15 mL of deionized water, 15 mL of anhydrous ethanol, and 4 mL of octylamine. Stir thoroughly until completely dissolved, and adjust the solution pH to 1 to obtain a mixed solution A. Precursor B with a preliminary layered structure was synthesized using a hot solvent method.

[0059] 2) Drying and recrystallizing the precursor B obtained by the solvent method to obtain mixed powder C (MoS2 / SA);

[0060] 3) Add an appropriate amount of precursor powder C, 244 mg of tris(hydroxymethyl)aminomethane, and 200 mg of dopamine hydrochloride to 200 ml of deionized water and stir for 24 hours to obtain a mixed solution D.

[0061] 4) Centrifuge four times and dry at 60°C for 12 h to obtain powder sample E (MoS2 / SA-PDA);

[0062] 5) Add powder E and 0.0238 g of cobalt chloride hexahydrate to 200 ml of deionized water, and stir at 100 rpm for 12 h at 30°C to obtain a mixed solution F.

[0063] 6) Drying and recrystallizing the mixed solution F to obtain mixed powder G (MoS2 / SA-PDA-Co);

[0064] 7) Powder G was heated at 750-800°C for 2 h in a 5% hydrogen, 95% argon environment to obtain MoS2 / C-SACo SL material.

[0065] The reasons why the superstructure material has excellent reaction kinetics and electrochemical properties are attributed to the following: the insertion of carbon materials and metal atoms expands the interlayer spacing of MS2, facilitating the transmission of ions; the composite with carbon materials enhances the stability of the results, which is conducive to obtaining stable electrochemical properties; the introduction of transition metal single atoms accelerates the transmission of electrons and ions; and the 100% surface contact MS2 / C-SAY catalytic interface effectively reduces the decomposition energy barrier of intermediate products.

Claims

1. A method for preparing a transition metal disulfide / carbon-supported metal single atom superstructure material, characterized in that: The following steps are involved: S1. Dissolving a transition metal inorganic salt as a transition metal disulfide, a sulfur source, and an organic matter as a carbon source in a mixture of deionized water and anhydrous ethanol to obtain a mixed solution A, adjusting the pH value of the mixed solution A to 1-2, and synthesizing a precursor B having a preliminary layered structure by a hot solvent method; S2, drying and recrystallizing the precursor B obtained by the hot solvent method to obtain a mixed powder C; S3, dissolving an appropriate amount of mixed powder C and an organic substance providing anchoring sites in a buffer system to obtain a mixed solution D; S4, drying and crystallizing the mixed solution D to obtain a powder sample E; S5, dissolving the powder sample E and the metal inorganic salt providing metal ions in a buffer system to obtain a mixed solution F; S6, drying and recrystallizing the mixed solution F to obtain a mixed powder G; S7. Place the mixed powder G in a tube furnace and keep it at 750-800°C for 1-3 hours in a 5% hydrogen, 95% argon environment to obtain a powder sample H, which is the superstructure material; wherein: The superstructure material is a superstructure nanosheet, and the expression of the superstructure nanosheet is MS2 / C-SAY SL, where MS2 is a transition metal disulfide, C is carbon, SAY is a single transition metal atom, and SL is a superstructure; the MS2 / C-SAY is a periodically arranged superstructure catalytic interface formed by alternating stacking of MS2 layers and C-SAY layers, wherein the MS2 layer is in 100% surface contact with the C-SAY layer.

2. The method for preparing a transition metal disulfide / carbon-supported metal single atom superstructure material according to claim 1, characterized in that: The transition metal inorganic salt is one or more of water-soluble molybdenum salt or water-soluble molybdate, water-soluble tungsten salt or water-soluble tungstate, and water-soluble tin salt.

3. The method for preparing a transition metal disulfide / carbon-supported metal single atom superstructure material according to claim 2, characterized in that: The water-soluble molybdate includes ammonium molybdate and sodium molybdate; the water-soluble tungstate includes ammonium tungstate, sodium tungstate and paratungstate; the water-soluble tin salt includes tin chloride and stannous chloride.

4. The method for preparing a transition metal disulfide / carbon-supported metal single atom superstructure material according to claim 1, characterized in that: The sulfur-containing source material is one or more of thiourea, sodium thiosulfate, urea, thioacetamide, L-cysteine, tetrathiomolybdate, sodium sulfide, potassium sulfide, thiomalic acid, ammonium sulfide, and ammonium hydrogen sulfide.

5. The method for preparing a transition metal disulfide / carbon-supported metal single atom superstructure material according to claim 1, characterized in that: The carbon source is one or more of octylamine, oleic acid, sodium oleate, glucose, glycerol, ethylenediamine, polyethylene compound, polyvinyl alcohol, and dopamine.

6. The method for preparing a transition metal disulfide / carbon-supported metal single atom superstructure material according to claim 1, characterized in that: The organic matter providing the anchoring point is one or more of dopamine, carbamate, vinylamide, aminophenol-formaldehyde resin, and carbamic acid amide.

7. The method for preparing a transition metal disulfide / carbon-supported metal single atom superstructure material according to claim 1, characterized in that: The metal inorganic salt providing metal ions is water-soluble chromium salt or water-soluble chromate, water-soluble manganese salt or water-soluble manganate or water-soluble permanganate, water-soluble iron salt, water-soluble cobalt salt, water-soluble nickel salt, water-soluble copper salt, water-soluble zinc salt and water-soluble niobium salt.

8. The method for preparing a transition metal disulfide / carbon-supported metal single atom superstructure material according to claim 7, characterized in that: The water-soluble chromium salts or water-soluble chromates include chromium nitrate, chromium perchlorate, chromium sulfate, chromium chloride, such as sodium chromate and potassium chromate; the water-soluble manganese salts or water-soluble manganates or water-soluble permanganates include manganese sulfate, manganese nitrate, manganese chloride, manganese acetate, potassium manganate and potassium permanganate; the water-soluble iron salts include ferric nitrate, ferric chloride, ferric citrate, ferric acetate, ferrous nitrate, ferrous chloride, ferric sulfate and ferrous sulfate; the water-soluble cobalt salts include cobalt sulfate, cobalt nitrate, cobalt chloride, cobalt acetate and cobalt citrate; the water-soluble nickel salts include nickel sulfate, nickel nitrate, nickel chloride, nickel acetate and nickel citrate; the water-soluble copper salts include copper nitrate, copper sulfate, copper chloride, copper acetate and copper citrate; the water-soluble zinc salts include zinc chloride, zinc sulfate, zinc nitrate, zinc fluoroborate, zinc gluconate and zinc acetate; the water-soluble niobium salts include ammonium niobium oxalate and niobium pentachloride.

9. The method for preparing a transition metal disulfide / carbon-supported metal single atom superstructure material according to claim 1, characterized in that: The drying and recrystallization method is one of heating drying, freeze drying and spray drying.

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