Biomass hard carbon sodium-ion battery negative electrode material and preparation method and application thereof

Abstract

This invention discloses a biomass hard carbon sodium-ion battery anode material, its preparation method, and its application. First, arbor-type biomass raw materials or domestic waste are repeatedly washed with water and then sequentially immersed in acid and oxidant to obtain clean biomass raw materials. Next, the clean biomass raw materials are crushed, sieved, and then immersed in a tin or indium solution with stirring, followed by freeze-drying to obtain a dry powder. The tin or indium solution contains phthalocyanine and / or porphyrin. Finally, the dry powder is subjected to high-temperature carbonization under an inert atmosphere, and after cooling, the biomass hard carbon sodium-ion battery anode material is obtained. This invention uses phthalocyanine and / or porphyrin as N4 / N5 precursors to prepare a biomass hard carbon sodium-ion battery anode material containing SnN4 or InN5 single-atom active centers, which exhibits performance at 50 mA g⁻¹. ‑1 The capacity exceeds 400mAh g ‑1 .

Description

Technical Field

[0001] This invention belongs to the field of sodium-ion battery technology, specifically relating to a biomass hard carbon sodium-ion battery anode material, its preparation method, and its application. Background Technology

[0002] Single-atom structures are considered a potential new material structure. Among them, carbon materials co-doped with metal (Me) and nitrogen (Me-NC) exhibit high electrochemical performance due to their unique coordination structure, thus attracting much attention in the fields of catalysis and batteries. The carbon composite structures such as MeN4 or MeN5 in Me-NC, with their unique porphyrin-like biomimetic structure, have been extensively studied in the fields of carbon dioxide reduction, oxygen reduction, catalytic hydrogen production, petrochemicals, and new energy batteries. Recent research, for example, has shown that hard carbon materials containing single-atom structures of carbon composite ZnN4 can widen the interlayer spacing of hard carbon materials, regulate the p-band electron structure of carbon, and catalyze the decomposition of NaPF6 to form a stable interface layer, thereby improving the rate capability and low-temperature performance of sodium-ion battery anodes.

[0003] Currently, there are many methods for preparing MeN4 or MeN5 structures, all of which involve high-temperature treatment of precursors composed of transition metal salts, nitrogen sources, and carbon sources. However, most methods are limited to preparing MeN4 or MeN5 structures with Zn, Co, and Fe elements. This is because Zn, Co, and Fe readily coordinate with dicyandiamide, pyrrole, imidazole, melamine, etc., forming spatial topological structures. For example, Zn and Co form ZIF-8 and ZIF-67 metal-organic framework materials with dimethylimidazolium, and their coordination environment is conducive to conversion into the corresponding MeN4 or MeN5 under high-temperature carbonization. Sn and In, being alkali metals, find it very difficult to form MeN4 or MeN5 structures in their coordination environment. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a biomass hard carbon sodium-ion battery anode material containing SnN4 or InN5 single-atom active centers, its preparation method, and its application. Using phthalocyanine and / or porphyrin as N4 / N5 precursors, a biomass hard carbon sodium-ion battery anode material containing SnN4 or InN5 single-atom active centers is prepared, which exhibits performance at 50 mA g⁻¹. -1 The capacity exceeds 400mAh g -1 .

[0005] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0006] A method for preparing a biomass hard carbon sodium-ion battery anode material includes the following steps:

[0007] Step 1: After washing the tree biomass raw materials or domestic waste multiple times, immerse them in acid and oxidant in sequence to obtain clean biomass raw materials.

[0008] Step 2: The clean biomass raw material obtained in Step 1 is crushed, sieved through a screen, immersed in a solution of tin or indium, stirred, and freeze-dried to obtain a dry powder; the solution of tin or indium contains phthalocyanine and / or porphyrin.

[0009] Step 3: The dried powder obtained in Step 2 is subjected to high-temperature carbonization under an inert atmosphere, and after cooling, the biomass hard carbon sodium-ion battery anode material is obtained.

[0010] Furthermore, the arbor biomass raw materials in step one include balsa wood, camellia fruit shells, etc.; domestic waste includes light industrial waste (such as waste wood chips from balsa wood furniture, discarded tailings, etc.) as well as root, stem, and bark residues of traditional Chinese medicine, such as one or more of Eucommia ulmoides, licorice, and dried tangerine peel.

[0011] Furthermore, the acid in step one is one or more of hydrofluoric acid, hydrochloric acid, perchloric acid, etc., with a concentration of 1-5 mol / L; the oxidant is one or more of hydrogen peroxide, sodium hypochlorite, etc., with an aqueous solution concentration of 2-20 wt.%.

[0012] Furthermore, in step two, the sieve mesh size is >300 mesh; the tin or indium solution is tin or indium nitrate, acetate, chloride, acetylacetone salt, etc., with a concentration of 1-50 mmol / L, and the solvent is a mixture of ethanol and water with a volume ratio of 2:1-1:3; the molar ratio of tin or indium to additives is 10:1-1:1.

[0013] Furthermore, the carbonization process in step three is carried out at a temperature of 1100–1500°C for 1–3 hours, under an atmosphere of argon or nitrogen.

[0014] The present invention also provides a biomass hard carbon sodium-ion battery anode material prepared by the above preparation method.

[0015] This invention also provides the application of the above-mentioned biomass hard carbon sodium-ion battery anode material, using it to prepare sodium-ion batteries.

[0016] The present invention has the following beneficial effects:

[0017] This invention involves adding phthalocyanine and / or porphyrin to a solution of tin or indium as a precursor for N4 / N5, thus successfully preparing a biomass hard carbon sodium-ion battery anode material containing single-atom active centers of SnN4 or InN5. The electric field formed by the single-atom active centers facilitates sodium ion transport and also catalyzes the decomposition of the electrolyte to form a stable interface layer, suppressing interface layer changes caused by rapid charge and discharge. Therefore, it exhibits excellent electrochemical activity, achieving a high efficiency at 50 mA g⁻¹.-1 The capacity exceeds 400mAh g -1 . Attached Figure Description

[0018] Figure 1 This is a synchrotron radiation characterization diagram of the biomass hard carbon sodium-ion battery anode material prepared in Example 1 of the present invention.

[0019] Figure 2 This is a graph showing the initial charge-discharge voltage-specific capacity curve of the biomass hard carbon sodium-ion battery anode material prepared in Example 1 of the present invention.

[0020] Figure 3 This is a graph showing the initial charge / discharge voltage-specific capacity curve of the biomass hard carbon sodium-ion battery anode material prepared in Example 2 of the present invention.

[0021] Figure 4 This is a graph showing the initial charge / discharge voltage-specific capacity curve of the biomass hard carbon sodium-ion battery anode material prepared in Comparative Example 1 of this invention.

[0022] Figure 5 This is a graph showing the initial charge / discharge voltage-specific capacity curve of the biomass hard carbon sodium-ion battery anode material prepared in Comparative Example 2 of this invention.

[0023] Figure 6 This is a graph showing the initial charge / discharge voltage-specific capacity curve of the biomass hard carbon sodium-ion battery anode material prepared in Comparative Example 3 of this invention.

[0024] Figure 7 The sodium-ion battery Na synthesized in Example 1 and Comparative Example 1 of this invention + Migration rate test graph. Detailed Implementation

[0025] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered by the claims.

[0026] Example 1

[0027] Step 1: Wash the camellia fruit shells multiple times with water to remove mud, sand, and surface mold. After pressing and drying, add them to 2 mol / L hydrochloric acid and stir at room temperature for 6 hours. Then press and filter, and wash with deionized water until neutral. Next, add them to 5 wt.% sodium hypochlorite solution and stir at room temperature for 6 hours. Then press and filter, wash with deionized water until neutral, and dry in an 80℃ oven to obtain clean biomass raw materials.

[0028] Step 2: Place the clean biomass raw material obtained in Step 1 into a crusher for crushing, sieve it through a 300-mesh sieve, and then immerse it in a 2 mmol / L tin acetate solution (wherein, the solvent is ethanol / water, volume ratio 1:1; the additive is phthalocyanine, concentration 2 mmol / L). After stirring for 2 hours, filter and freeze dry to obtain a dry powder.

[0029] Step 3: The dried powder obtained in Step 2 is heated under argon gas (flow rate 100 sccm, pressure 1 bar) at 2℃ for 2 min. -1 The temperature was increased to 1300℃ at a heating rate and held for 3 hours. After natural cooling, the biomass hard carbon sodium-ion battery anode material was obtained.

[0030] Example 2

[0031] Step 1: Wash the Eucommia ulmoides residue (Liaoning Chunguang Pharmaceutical) with water multiple times to remove mud, sand and surface mold. After pressure filtration and drying, add it to 5 wt.% hydrofluoric acid and stir at room temperature for 6 hours. Then filter it and wash it with deionized water until neutral. Next, add it to 5 wt.% sodium hypochlorite solution and stir at room temperature for 6 hours. Then filter it and wash it with deionized water until neutral. Place it in an 80℃ oven to dry, and you will get clean biomass raw materials.

[0032] Step 2: Place the clean biomass raw material obtained in Step 1 into a crusher for crushing, sieve it through a 300-mesh sieve, and then immerse it in a 2 mmol / L indium acetate solution (wherein, the solvent is ethanol / water, volume ratio 1:1; the additive is phthalocyanine, concentration 2 mmol / L). After stirring for 2 hours, filter and freeze dry to obtain a dry powder.

[0033] Step 3: The dried powder obtained in Step 2 is heated under argon gas (flow rate 100 sccm, pressure 1 bar) at 2℃ for 2 min. -1 The temperature was increased to 1300℃ at a heating rate and held for 3 hours. After natural cooling, the biomass hard carbon sodium-ion battery anode material was obtained.

[0034] Comparative Example 1

[0035] Step 1: Wash the camellia fruit shells multiple times with water to remove mud, sand, and surface mold. After pressing and drying, add them to 2 mol / L hydrochloric acid and stir at room temperature for 6 hours. Then press and filter, and wash with deionized water until neutral. Next, add them to 5 wt.% sodium hypochlorite solution and stir at room temperature for 6 hours. Then press and filter, wash with deionized water until neutral, and dry in an 80℃ oven to obtain clean biomass raw materials.

[0036] Step 2: Place the clean biomass raw material obtained in Step 1 into a crusher for crushing, and then sieve it through a 300-mesh screen to obtain fine powder.

[0037] Step 3: The fine powder obtained in Step 2 is heated under argon gas (flow rate 100 sccm, pressure 1 bar) at 2℃ for 1 minute. -1 The temperature was increased to 1300℃ at a heating rate and held for 3 hours. After natural cooling, the biomass hard carbon sodium-ion battery anode material was obtained.

[0038] Comparative Example 2

[0039] Step 1: Wash the Eucommia ulmoides residue (Liaoning Chunguang Pharmaceutical) with water multiple times to remove mud, sand and surface mold. After pressure filtration and drying, add it to 5 wt.% hydrofluoric acid and stir at room temperature for 6 hours. Then filter it and wash it with deionized water until neutral. Next, add it to 5 wt.% sodium hypochlorite solution and stir at room temperature for 6 hours. Then filter it and wash it with deionized water until neutral. Place it in an 80℃ oven to dry, and you will get clean biomass raw materials.

[0040] Step 2: Place the clean biomass raw material obtained in Step 1 into a crusher for crushing, and then sieve it through a 300-mesh screen to obtain fine powder.

[0041] Step 3: The fine powder obtained in Step 2 is heated under argon gas (flow rate 100 sccm, pressure 1 bar) at 2℃ for 1 minute. -1 The temperature was increased to 1300℃ at a heating rate and held for 3 hours. After natural cooling, the biomass hard carbon sodium-ion battery anode material was obtained.

[0042] Comparative Example 3

[0043] Step 1: Wash the camellia fruit shells multiple times with water to remove mud, sand, and surface mold. After pressing and drying, add them to 2 mol / L hydrochloric acid and stir at room temperature for 6 hours. Then press and filter, and wash with deionized water until neutral. Next, add them to 5 wt.% sodium hypochlorite solution and stir at room temperature for 6 hours. Then press and filter, wash with deionized water until neutral, and dry in an 80℃ oven to obtain clean biomass raw materials.

[0044] Step 2: Place the clean biomass raw material obtained in Step 1 into a crusher for crushing, and after sieving through a 300-mesh sieve, immerse it in 2 mmol / L tin acetate (wherein, the solvent is ethanol / water, volume ratio 1:1; the additive is dicyandiamide, concentration 8 mmol / L), stir for 2 hours, filter and freeze dry to obtain dry powder.

[0045] Step 3: The dried powder obtained in Step 2 is heated under argon gas (flow rate 100 sccm, pressure 1 bar) at 2℃ for 2 min. -1 The temperature was increased to 1300℃ at a heating rate and held for 3 hours. After natural cooling, the biomass hard carbon sodium-ion battery anode material was obtained.

[0046] Performance testing:

[0047] Battery performance testing involved coating the prepared negative electrode material onto copper foil as the working electrode, using pure sodium as the counter electrode, NaPF6 (1M) as the electrolyte solute, and EC:DMC = 1:1 as the solvent. Tests were conducted at different current densities and at a low temperature of -40°C. The results are shown in Table 1.

[0048] Table 1. Battery performance test results for the examples and comparative examples.

[0049] sample Reversible specific capacity (50mAh / g) sample Reversible specific capacity (50mAh / g) Example 1 <![CDATA[407mA·h·g -1 ]]> Example 2 <![CDATA[412mA·h·g -1 ]]> Comparative Example 1 <![CDATA[313mA·h·g -1 ]]> Comparative Example 2 <![CDATA[335mA·h·g -1 ]]> Comparative Example 3 <![CDATA[346mA·h·g -1 ]]>

[0050] As shown in Table 1, Examples 1-2 and Comparative Examples 1-2 demonstrate that the hard carbon material doped with single-atom active centers exhibits significantly better electrochemical performance than the hard carbon material without single-atom doping. Furthermore, Examples 1 and Comparative Example 3 show that, compared to dicyandiamide, using phthalocyanine as a precursor for N4 resulted in a unique SnN4 single-atom doped structure. Figure 1 It has a higher reversible specific capacity.

[0051] like Figure 7 As shown, testing the sodium ion migration rate demonstrates that doping with a single atom of Sn significantly improves the Na+ ion migration rate. + The migration rate is thus beneficial to the electrochemical performance of hard carbon.

Claims

1. A method for preparing a negative electrode material for a biomass hard carbon sodium-ion battery, characterized in that, Includes the following steps: Step 1: After washing the tree biomass raw materials or domestic waste multiple times, immerse them in acid and oxidant in sequence to obtain clean biomass raw materials. Step 2: The clean biomass raw material obtained in Step 1 is crushed, sieved through a screen, immersed in a solution of tin or indium, stirred, and freeze-dried to obtain a dry powder; the solution of tin or indium contains phthalocyanine and / or porphyrin. Step 3: The dried powder obtained in Step 2 is subjected to high-temperature carbonization under an inert atmosphere, and after cooling, the biomass hard carbon sodium-ion battery anode material is obtained.

2. The preparation method according to claim 1, characterized in that, The arbor biomass raw materials in step one are one or more of balsa wood and camellia fruit shells; the domestic waste is one or more of light industrial waste, root, stem, and bark residues of traditional Chinese medicine.

3. The preparation method according to claim 1, characterized in that, The acid in step one is one or more of hydrofluoric acid, hydrochloric acid, and perchloric acid, with a concentration of 1–5 mol / L; the oxidant is one or more of hydrogen peroxide and sodium hypochlorite, with an aqueous solution concentration of 2–20 wt.%.

4. The preparation method according to claim 1, characterized in that, In step two, the sieve mesh size is >300 mesh; the tin or indium solution is tin or indium nitrate, acetate, chloride, or acetylacetone salt with a concentration of 1-50 mmol / L, and the solvent is a mixture of ethanol and water with a volume ratio of 2:1-1:3; the molar ratio of tin or indium to additives is 10:1-1:

1.

5. The preparation method according to claim 1, characterized in that, The carbonization process in step three is carried out at a temperature of 1100–1500℃ for 1–3 hours in an atmosphere of argon or nitrogen.

6. The biomass hard carbon sodium-ion battery anode material prepared by the preparation method according to any one of claims 1-5.

7. The application of the biomass hard carbon sodium-ion battery anode material according to claim 6, characterized in that, It is used to prepare sodium-ion batteries.

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