Composite materials of transition metals and poor metals with sulfur, selenium, and tellurium, and their preparation and applications

Abstract

This application discloses a composite material of transition metals and poor metals sulfur-selenium-tellurium, its preparation and application, belonging to the field of anode materials for sodium-ion batteries, and its chemical formula is [(1-w)A n S m / wA p Se q B x Te y @rGO, A n S m phase forms a heterojunction structure with A p Se q . A n S m and A p Se q 's mixed phase is further coated by B x Te y phase and form a heterojunction structure with each other, and form particles coated with amorphous carbon, and the particles are dispersed on the surface of reduced graphene oxide. This application not only forms a three-layer heterojunction structure, improves the ion diffusion kinetics, but also introduces telluride to further improve the reaction kinetics of the material. Therefore, the anode material for sodium-ion batteries made of this composite has excellent rate performance and cycle stability performance.

Description

Technical Field

[0001] The present invention relates to the field of anode materials for sodium-ion batteries, and particularly to a composite material of transition metal and poor metal sulfur-selenium-tellurium, and its preparation and application. Background Art

[0002] With the irreversible consumption of fossil energy, the application value of lithium-ion batteries has become increasingly irreplaceable. However, due to the relatively low crustal abundance of lithium resources, it has seriously affected the wide application of lithium-ion batteries. As a sodium element in the same group as lithium, it has a high crustal abundance and a similar energy storage mechanism to lithium, making sodium-ion batteries gradually become a research hotspot in academia and industry.

[0003] Currently, driven by the increasing energy demand of people, high specific energy and high power have become the development direction of secondary batteries. The key lies in the high voltage of the positive electrode material and the high capacity of the negative electrode. However, since the sodium ion radius is larger than the lithium ion radius, electrode materials with good lithium storage performance do not necessarily have good sodium storage performance. Therefore, the demand for anode materials with high specific capacity for sodium-ion batteries is one of the key problems in solving the application of sodium-ion batteries at present.

[0004] Composite materials of transition metal and poor metal sulfur-selenium-tellurium, transition metal selenides, poor metal selenides, and poor metal tellurides all have good lithium / sodium intercalation performance. Since selenium has better metallicity than sulfur, transition metal selenides have higher conductivity than sulfides; since sulfur has a smaller molecular weight than selenium, metal sulfides have a higher theoretical specific capacity than selenides. And poor metal tellurides, as a semiconductor alloy, have excellent conductivity and higher theoretical specific capacity. However, due to the volume expansion of its negative electrode during the cycling process, it is extremely easy to cause performance degradation, making it difficult to reach the theoretical capacity. Combining poor metal tellurides with the heterojunctions of composite materials of transition metal and poor metal sulfur-selenium-tellurium and poor metal selenides can effectively reduce its performance degradation. In summary, preparing a composite material of transition metal and poor metal sulfur-selenium-tellurium will effectively improve the intrinsic conductivity and theoretical specific capacity of the material, and electrode materials with good battery performance can be designed. However, in the actual preparation process, due to the easy aggregation of selenium metal particles, the final composite material has an irregular morphology, and the specific capacity and cycling performance cannot reach the expected effect.

[0005] Patent CN 110571416 B discloses a transition metal selenium-sulfur composite and its preparation method. Although it significantly improves the rate performance and cycling stability performance of the electrode material, and the preparation method effectively avoids the irregular morphology caused by the aggregation of iron diselenide particles, selenium-sulfur compounds are all semiconductor materials with poor electron conductivity, which is not conducive to the reaction kinetics of the material during the energy storage process. Summary of the Invention

[0006] To solve the above problems, the present invention provides a composite material of transition metal and poor metal sulfur-selenium-tellurium, and its preparation and application. The present invention designs a three-layer heterojunction structure, namely the heterojunction structure between sulfide and selenide, the heterojunction structure between telluride and metal sulfur-selenium composite, and the heterostructure between graphene and transition metal and poor metal sulfur-selenium-tellurium composite. The design of the three-layer heterojunction structure will form a built-in electric field, which helps ions enter the material from the electrolyte and diffuse rapidly within the material to improve ion diffusion kinetics. Among them, the design of telluride not only provides a heterojunction structure, but also itself is an alloy material with good electronic conductivity, thus further improving the reaction kinetics of the material. Therefore, the negative electrode material for sodium-ion batteries made of this composite has excellent rate performance and cycle stability performance.

[0007] The present invention provides a composite material of transition metal and poor metal sulfur-selenium-tellurium, and its chemical formula is [(1-w)A n S m / wA p Se q B x Te y @rGO, A n S m phase forms a heterojunction structure with A p Se q phase, and the mixed phase of A n S m and A p Se q is further coated by B x Te y phase to form a heterojunction structure with each other, and form particles coated with amorphous carbon, and the particles are dispersed on the surface of reduced graphene oxide.

[0008] Preferably, A is one or more of Zn, Co, Sn, Fe, Bi, Mo, V, Mn and Sb, B is one or more of Zn, Co, Sn, Fe, Bi, Mo, V, Mn and Sb, and the value range of w is 0 < w < 1.

[0009] The present invention provides a preparation method of a composite material of transition metal and poor metal sulfur-selenium-tellurium, including the following steps:

[0010] S1: React the complexing agent I with the metal salt solution of A to obtain metal-organic framework I;

[0011] S2: Carry out a solvothermal reaction on the metal-organic framework I obtained in step S1 with a sulfur source solution and a selenium source solution to generate a transition metal and poor metal sulfur-selenium composite;

[0012] S3: React the transition metal and poor metal sulfur-selenium composite obtained in step S2 with a metal salt solution of complexing agent I and B to obtain a metal sulfur-selenium composite coated with metal-organic framework II;

[0013] S4: Calcinate the metal sulfur-selenium composite coated with metal-organic framework II obtained in step S3 with tellurium powder at high temperature under an inert atmosphere to obtain a transition metal and poor metal selenium-sulfur-tellurium composite;

[0014] S5: Calcinate the transition metal and poor metal selenium-sulfur-tellurium composite in step S4 with a graphene oxide dilution solution at high temperature under an inert atmosphere to obtain a transition metal and poor metal selenium-sulfur-tellurium composite coated with graphene oxide.

[0015] Preferably, in step S1, the molar ratio of element A in the metal salt solution of complexing agent I and A is 1-100 mol: 1 mol; the complexing agent I is one or more of 2-methylimidazole, terephthalic acid and trimesic acid; the concentration of element A in the metal salt solution of A is 0.03-0.1 mol / L; the concentration of the complexing agent I solution is 0.1-5 mol / L;

[0016] Preferably, in step S2, the metal-organic framework I is dispersed in solvent I to form a suspension, and a solvothermal reaction is carried out with a sulfur source solution and a selenium source solution; the temperature of the solvothermal reaction is 120-300 °C, and the time is 6-30 h; the sulfur source is selected from one or more of thioacetamide, sodium sulfide and L-cysteine; the molar concentration of the sulfur source solution is 0.2-2 mol / L, the selenium source is selected from one or more of selenic acid, sodium selenate and sodium selenite; the molar concentration of the selenium source is 0.1-2.2 mol / L; the molar ratio of element A to sulfur element in the transition metal and poor metal sulfur-selenium composite is 1 mol: 1-8 mol; in the transition metal and poor metal sulfur-selenium composite, the molar ratio of sulfur element to selenium element is 1 mol-10 mol: 1 mol.

[0017] Preferably, in step S3, the molar ratio of element B in the metal salt solution of complexing agent I and B is 1-100 mol: 1 mol; the concentration of element B in the metal salt solution of B is 0.02-0.1 mol / L.

[0018] Preferably, in step S4, the high-temperature calcination is carried out in a tube furnace, the temperature is 500-900 °C, the high-temperature treatment time is 0.5-24 h, and the gas of the atmosphere is one or more of a nitrogen-hydrogen mixed gas with 5% hydrogen content, an argon-hydrogen mixed gas with 5% hydrogen content, nitrogen, and argon.

[0019] Preferably, in the graphene oxide diluent in step S5, the mass ratio of the transition metal and poor metal selenium-sulfur-tellurium composite to graphene oxide is 10:1-3.

[0020] Preferably, the solvents in the solvothermal method, the metal salt solution of A, and the metal salt solution of B are each selected from one or more of deionized water, ethanol, methanol, N,N-dimethylformamide, and ethylene glycol; preferably, the solvent I is selected from one or more of deionized water, ethanol, and methanol, and more preferably, the solvent I is one or more of methanol and deionized water.

[0021] The present invention provides an application of the above-mentioned composite material of transition metal and poor metal sulfur-selenium-tellurium in energy storage batteries.

[0022] Therefore, the composite material of transition metal and poor metal sulfur-selenium-tellurium provided by the present invention and its preparation and application have the following beneficial effects:

[0023] (1) In the composite material of the present invention, A n S m 、A p Se q and the alloy phase B x Te y mutually form a heterojunction structure. The A n S m phase and the A p Se q phase are uniformly dispersed and form a heterojunction structure. The mixed phase of A n S m and A p Se q is further coated by the B x Te y phase and mutually forms a heterojunction structure, and composes particles coated with amorphous carbon. The particles are uniformly dispersed on the surface of reduced graphene oxide, and then the formed A n S m and A p Se q are uniformly dispersed and uniformly coated by the alloy phase B x Te y to form a transition metal and poor metal sulfur-selenium-tellurium three-phase alloy composite. Therefore, the anode material prepared from the composite has excellent rate performance and cycle stability;

[0024] (2) The preparation method of the present invention can effectively avoid the agglomeration problem of transition metal particles when using the liquid phase deposition method, so that A n S m 、A p Se q and the alloy phase B x Tey They form a heterojunction structure with each other and form particles uniformly dispersed on the surface of graphene. Moreover, the graphene combines with the amorphous carbon on the surface of the particles to form a three-dimensional carbon coating layer, improving the structural stability and conductivity of the material. Combining with the defects formed by the heterostructure further improves the structural stability and conductivity of the material, thereby realizing excellent cycle and rate performance of the material.

[0025] (3) By introducing an alloy, the present invention improves the electronic conductivity of the material; forms a multi-dimensional heterostructure to construct a multi-internal electric field and improve the ion diffusion rate. Through this structure, the reaction kinetics of the material is improved synchronously. Description of the Drawings

[0026] Figure 1 is the SEM image of the composite material of transition metal and poor metal sulfur-selenium-tellurium prepared in Example 1 of the present invention;

[0027] Figure 2 is the SEM-EDS image of the prepared product in Example 1 of the present invention. Among them, a is the SEM image of the prepared product; b is the SEM-Mapping image of Se element, c is the SEM-Mapping image of Te element, and d is the SEM-Mapping image of S element.

[0028] Figure 3 is the impedance image of the prepared products in Example 1 and Comparative Example 1 of the present invention. Detailed Embodiments

[0029] The present invention provides a composite material of transition metal and poor metal sulfur-selenium-tellurium, with the chemical formula [(1-w)A n S m / wA p Se q B x Te y @rGO, A n S m phase forms a heterojunction structure with A p Se q phase, and the mixed phase of A n S m and A p Se q is further coated by B x Te y phase to form a heterojunction structure with each other, and form particles coated with amorphous carbon, and the particles are dispersed on the surface of reduced graphene oxide; preferably, A is one or more of Zn, Co, Sn, Fe, Bi, Mo, V, Mn, and Sb, B is one or more of Zn, Co, Sn, Fe, Bi, Mo, V, Mn, and Sb, and the value range of w is 0 < w < 1.

[0030] The present invention provides a method for preparing a composite material of transition metal and poor metal sulfur-selenium-tellurium, comprising the following preparation steps:

[0031] S1: React a complexing agent I with a metal salt solution of A to obtain a metal-organic framework I; the molar ratio of element A in the complexing agent I and the metal salt solution of A is 1-100 mol:1 mol; the complexing agent I is one or more of 2-methylimidazole, terephthalic acid, and trimesic acid; the concentration of element A in the metal salt solution of A is 0.03-0.1 mol / L; the concentration of the complexing agent I solution is 0.1-5 mol / L;

[0032] S2: Perform a solvothermal reaction on the metal-organic framework I obtained in step S1 with a sulfur source solution and a selenium source solution to generate a transition metal and poor metal sulfur-selenium composite; the metal-organic framework I is dispersed in a solvent I to form a suspension, and a solvothermal reaction is carried out with the sulfur source solution and the selenium source solution; the temperature of the solvothermal reaction is 120-300 °C, and the time is 6-30 h; the sulfur source is selected from one or more of thioacetamide, sodium sulfide, and L-cysteine; the molar concentration of the sulfur source solution is 0.2-2 mol / L, the selenium source is selected from one or more of selenic acid, sodium selenate, and sodium selenite; the molar concentration of the selenium source is 0.1-2.2 mol / L; in the transition metal and poor metal sulfur-selenium composite, the molar ratio of element A to sulfur element is 1 mol:1-8 mol; in the transition metal and poor metal sulfur-selenium composite, the molar ratio of sulfur element to selenium element is 1 mol-10 mol:1 mol.

[0033] S3: React the transition metal and poor metal sulfur-selenium composite obtained in step S2 with the complexing agent I and a metal salt solution of B to obtain a metal sulfur-selenium composite coated with a metal-organic framework II; the molar ratio of element B in the complexing agent I and the metal salt solution of B is 1-100 mol:1 mol; the concentration of element B in the metal salt solution of B is 0.02-0.1 mol / L;

[0034] S4: Calcinate the metal sulfur-selenium composite coated with the metal-organic framework II obtained in step S3 with tellurium powder under an inert atmosphere to obtain a transition metal and poor metal selenium-sulfur-tellurium composite; the high-temperature calcination is carried out in a tube furnace, the temperature is 500-900 °C, the high-temperature treatment time is 0.5-24 h, and the gas of the atmosphere is one or more of a nitrogen-hydrogen mixed gas with 5% hydrogen content, an argon-hydrogen mixed gas with 5% hydrogen content, nitrogen, and argon;

[0035] S5: High-temperature calcine the transition metal and poor metal selenium-sulfur-tellurium composite obtained in step S4 with the graphene oxide dilution solution in an inert atmosphere to obtain a graphene oxide-coated transition metal and poor metal selenium-sulfur-tellurium composite. In the graphene oxide dilution solution, the mass ratio of the transition metal and poor metal selenium-sulfur-tellurium composite to graphene oxide is 10:1 - 3.

[0036] The solvents in the solvothermal method, the metal salt solution of A, and the metal salt solution of B are each selected from one or more of deionized water, ethanol, methanol, N,N-dimethylformamide, and ethylene glycol; preferably, the solvent I is selected from one or more of deionized water, ethanol, and methanol, and more preferably, the solvent I is one or more of methanol and deionized water.

[0037] The present invention provides an application of the above-mentioned composite material of transition metal and poor metal sulfur-selenium-tellurium in energy storage batteries.

[0038] Example 1

[0039] The composite material of transition metal and poor metal sulfur-selenium-tellurium includes the following steps:

[0040] (1) Weigh 1.1508 g of zinc nitrate and dissolve it in 100 mL of methanol to form a zinc nitrate solution. Weigh 1.6231 g of 2-methylimidazole and dissolve it in 100 mL of methanol to form a 2-methylimidazole solution. After complete dissolution, pour the 2-methylimidazole solution into the zinc nitrate solution and let it stand at room temperature for 20 h. After centrifugation, washing, and drying with hot air, obtain metal-organic framework I;

[0041] (2) Disperse metal-organic framework I in 10 ml of deionized water to form a suspension. Weigh 3.5 mmol of thioacetamide and 3.5 mmol of selenic acid, dissolve them in 10 ml of deionized water to form a reaction solution, add it to the suspension, stir at room temperature for 5 min, and perform a hydrothermal reaction at 160 °C for 12 h. After the reaction, obtain the intermediate product transition metal and poor metal sulfur-selenium composite 0.7ZnS / 0.3ZnSe after centrifugation, washing, and drying;

[0042] (3) Take 0.5 mmol of the transition metal and poor metal sulfur-selenium composite and fully dissolve it in 100 ml of antimony sulfate solution. Then add 1.6231 g of 2-methylimidazole weighed and dissolved in 100 mL of methanol to form a 2-methylimidazole solution. After complete dissolution, pour the 2-methylimidazole solution into the antimony sulfate solution containing 0.5 mmol of the transition metal and poor metal sulfur-selenium composite, let it stand at room temperature for 20 h, and obtain the metal-organic framework II-coated metal sulfur-selenium composite (metal sulfur-selenium composite @II) after centrifugation, washing, and drying with hot air;

[0043] (4) Mix 0.5 mmol of tellurium powder into the metal sulfoselenide @Ⅱ, grind it evenly, place it in a quartz porcelain boat, and transfer the quartz porcelain boat to a tube furnace. Under the protection of an argon-hydrogen atmosphere, calcine it at 600 °C for 3 h with a heating rate of 5 °C / min to obtain a transition metal and poor metal selenium-sulfur-tellurium composite (0.7ZnS / 0.3ZnSe)Sb 2 Te 3 .

[0044] (5) Take 0.5 mmol of the transition metal and poor metal selenium-sulfur-tellurium composite, disperse it fully in 50 ml of deionized water containing 30 mg of graphene oxide, stir for 1 h, ultrasonicate for 1 h, repeat three times, and after freeze-drying, sinter it at 450 °C for 1 h in a nitrogen environment to obtain the final product of the transition metal and poor metal (0.7ZnS / 0.3ZnSe)Sb 2 Te 3 @rGO.

[0045] It can be analyzed by using a scanning electron microscope ( Figure 1 ) that the product is hollow small squares about 500 nm in size and is uniformly coated with graphene. Among them, the hollow small squares are stacked by small particles composed of a uniform mixture distribution of two phases of ZnS and ZnSe. Heterojunctions are formed at the triple junction of ZnS, ZnSe and Sb 2 Te 3 , causing defects and improving the conductivity of the material.

[0046] Weigh the above-prepared product, acetylene black (conductive agent) and PVDF (HS V900, binder) according to the mass ratio of 7:2:1 respectively. After fully grinding, add an appropriate amount of NMP to disperse and mix them into a viscous paste. Then, evenly coat the paste on the copper foil. After drying at 85 °C with blowing, cut it into circular pieces with a diameter of 12 mm, and assemble it in a glove box with an argon atmosphere. Use a sodium metal sheet as the counter electrode, a 1M NaPF6 solution (the volume ratio of the solvent EC:DEC is 1:1) as the electrolyte, and a glass fiber (Grade GF / F) as the separator to assemble a CR2032 type button cell. At 25 °C, when performing a constant current charge-discharge test at a rate of 100 mAg -1 between 0.1 - 3.0 V, the initial charge capacity of the battery is 516.3 mAhg -1 . At 25 °C, when performing a constant current charge-discharge test at a rate of 0.5 Ag -1 in the range of 0.1 - 3.0 V, the charge specific capacity after 500 cycles is 346.5 mAhg -1 .

[0047] Example 2

[0048] The composite material of transition metal and poor metal sulfur-selenium-tellurium of the present invention includes the following steps:

[0049] (1) Weigh 1.1508 g of zinc nitrate and dissolve it in 100 mL of methanol to form a zinc nitrate solution. Weigh 1.6231 g of 2-methylimidazole and dissolve it in 100 mL of methanol to form a 2-methylimidazole solution. After complete dissolution, pour the 2-methylimidazole solution into the zinc nitrate solution and let it stand at room temperature for 20 h. Then, obtain metal-organic framework I through centrifugation, washing, and drying with hot air.

[0050] (2) Disperse metal-organic framework I in 10 mL of deionized water to form a suspension. Weigh 3.5 mmol of thioacetamide and 3.5 mmol of selenic acid, dissolve them in 10 mL of deionized water to form a reaction solution, add it to the suspension, stir at room temperature for 5 min, and carry out a hydrothermal reaction at 200 °C for 12 h. After the reaction, obtain the intermediate product, transition metal and poor metal sulfur-selenium composite 0.7ZnS / 0.3ZnSe, through centrifugation, washing, and drying.

[0051] (3) Take 0.5 mmol of the transition metal and poor metal sulfur-selenium composite and dissolve it completely in 100 mL of antimony sulfate solution. Then, weigh 1.6231 g of 2-methylimidazole and dissolve it in 100 mL of methanol to form a 2-methylimidazole solution. After complete dissolution, pour the 2-methylimidazole solution into the antimony sulfate solution containing 0.5 mmol of the transition metal and poor metal sulfur-selenium composite, let it stand at room temperature for 20 h, and obtain the metal sulfur-selenium composite coated with metal-organic framework II (metal sulfur-selenium composite@II) through centrifugation, washing, and drying with hot air.

[0052] (4) Mix 0.5 mmol of tellurium powder into the metal sulfur-selenium composite@II, grind it evenly, place it in a quartz porcelain boat, and transfer the quartz porcelain boat to a tubular furnace. Under the protection of an argon-hydrogen atmosphere, calcine it at 600 °C for 3 h with a heating rate of 5 °C / min to obtain the transition metal and poor metal selenium-sulfur-tellurium composite (0.7ZnS / 0.3ZnSe)Sb 2 Te 3 。

[0053] (5) Take 0.5 mmol of the transition metal and poor metal selenium-sulfur-tellurium composite, disperse it fully in 50 mL of deionized water containing 30 mg of graphene oxide, stir for 1 h, ultrasonicate for 1 h, repeat three times, and after freeze-drying, sinter it at 450 °C for 1 h in a nitrogen environment to obtain the final product, transition metal and poor metal (0.7ZnS / 0.3ZnSe)Sb 2 Te 3 @rGO.

[0054] The above-prepared product, acetylene black (conductive agent) and PVDF (HS V900, binder) were weighed in a mass ratio of 7:2:1, and after being fully ground, an appropriate amount of NMP was added to disperse and mix until a viscous slurry was formed. The slurry was then evenly coated on a copper foil, dried at 85°C with a blast airflow, and cut into discs with a diameter of 12 mm. The discs were assembled in an argon atmosphere glove box, with a metal sodium sheet as the counter electrode and 1 M NaPF 6 The solution (solvent EC:DEC volume ratio is 1:1) is used as the electrolyte, and the glass fiber (GradeGF / F) is used as the separator to assemble a CR2032 button cell. Figure 2 It can be seen that at 25°C, 100mAg -1 When the constant current charge and discharge test was carried out at a rate between 0.1-3.0V, the initial charge capacity of the battery was 490.5mAhg -1 At 25°C, 1Ag -1 The constant current charge and discharge test was carried out in the range of 0.1-3.0V at a rate of 1.5 times. The charge capacity after 500 cycles was 353.4mAhg -1 .

[0055] Example 3

[0056] The preparation of the transition metal and metal-poor sulfur-selenium-tellurium composite material of the present invention comprises the following steps:

[0057] (1) Weigh 0.4569 g of tin nitrate and dissolve it in 100 mL of methanol, weigh 8.8274 g of 2-methylimidazole and dissolve it in 100 mL of methanol, and after fully dissolving, pour the 2-methylimidazole solution into the tin nitrate solution and let it stand at room temperature for 20 hours, centrifuge, wash, and air dry to obtain metal organic framework I;

[0058] (2) The metal organic framework I was dispersed in 10 ml of deionized water to form a suspension, 3.5 mmol of thioacetamide and 3.5 mmol of selenic acid were weighed and dissolved in 10 ml of deionized water to form a reaction solution, which was added to the suspension and stirred at room temperature for 5 min. The suspension was subjected to hydrothermal reaction at 160° C. for 12 h. After the reaction was completed, the intermediate product transition metal and poor metal sulfur-selenium complex 0.7SnS was obtained by centrifugation, washing and drying. 2 / 0.3SnSe 2 ;

[0059] (3) Dissolve 0.5 mmol of the transition metal and poor metal sulfur-selenium composite completely in 100 ml of antimony sulfate solution. Then, weigh 1.6231 g of 2-methylimidazole and dissolve it in 100 mL of methanol to form a 2-methylimidazole solution. After complete dissolution, pour the 2-methylimidazole solution into the antimony sulfate solution containing 0.5 mmol of the transition metal and poor metal sulfur-selenium composite, and let it stand at room temperature for 20 h. After centrifugation, washing, and drying with a blower, a metal-organic framework II-coated metal sulfur-selenium composite (metal sulfur-selenium composite@II) is obtained;

[0060] (4) Mix 0.5 mmol of tellurium powder into the metal sulfur-selenium composite@II, grind it evenly, place it in a quartz boat, and transfer the quartz boat to a tube furnace. Under the protection of an argon-hydrogen atmosphere and at a heating rate of 5 °C / min, calcine it at 600 °C for 3 h to obtain a transition metal and poor metal selenium-sulfur-tellurium composite (0.7ZnS 2 / 0.3ZnSe 2 )Sb 2 Te3.

[0061] (5) Take 0.5 mmol of the transition metal and poor metal selenium-sulfur-tellurium composite, disperse it fully in 50 ml of deionized water containing 30 mg of graphene oxide, stir for 1 h, sonicate for 1 h, repeat three times, and after freeze-drying, sinter it at 450 °C for 1 h in a nitrogen environment to obtain the final product, the transition metal and poor metal (0.7SnS 2 / 0.3SnSe 2 )Sb 2 Te 3 @rGO.

[0062] Weigh the above-prepared product, acetylene black (conductive agent), and PVDF (HS V900, binder) according to a mass ratio of 7:2:1, grind them fully, add an appropriate amount of NMP, disperse and mix them until they become a viscous paste. Then, evenly coat the paste on the copper foil, dry it at 85 °C with a blower, cut it into circular pieces with a diameter of 12 mm, and assemble it in a glove box under an argon atmosphere. Use a sodium metal sheet as the counter electrode, a 1M NaPF 6 solution (the volume ratio of the solvent EC:DEC is 1:1) as the electrolyte, and a glass fiber (Grade GF / F) as the separator to assemble a CR2032-type button cell. As shown in Table 4, at 25 °C, when a constant current charge-discharge test is carried out at a rate of 100 mAg -1 between 0.1 - 3.0 V, the first charge capacity of the battery is 490.2 mAhg -1 . At 25 °C, when a constant current charge-discharge test is carried out at a rate of 1Ag -1 in the range of 0.1 - 3.0 V, the charge specific capacity after 500 cycles is 261.4 mAhg -1 .

[0063] Example 4

[0064] To prepare the composite material of transition metal and poor metal sulfur-selenium-tellurium of the present invention, the following steps are included:

[0065] (1) Weigh 0.4569 g of stannic nitrate and dissolve it in 100 mL of methanol. Weigh 8.8274 g of 2-methylimidazole and dissolve it in 100 mL of methanol. After complete dissolution, pour the 2-methylimidazole solution into the stannic nitrate solution, and let it stand at room temperature for 20 h. After centrifugation, washing, and drying with air blast, metal-organic framework Ⅰ is obtained;

[0066] (2) Disperse metal-organic framework Ⅰ in 10 ml of deionized water to form a suspension. Weigh 3.5 mmol of thioacetamide and 3.5 mmol of selenic acid, dissolve them in 10 ml of deionized water to form a reaction solution, add it to the suspension, stir at room temperature for 5 min, and carry out hydrothermal reaction at 200 °C for 12 h. After the reaction is completed, after centrifugation, washing, and drying, the intermediate product transition metal and poor metal sulfur-selenium complex 0.7SnS 2 / 0.3SnSe 2 ;

[0067] (3) Take 0.5 mmol of the transition metal and poor metal sulfur-selenium complex and dissolve it completely in 100 ml of antimony sulfate solution. Then weigh 1.6231 g of 2-methylimidazole and dissolve it in 100 mL of methanol to form a 2-methylimidazole solution. After complete dissolution, pour the 2-methylimidazole solution into the antimony sulfate solution containing 0.5 mmol of the transition metal and poor metal sulfur-selenium complex, let it stand at room temperature for 20 h, and after centrifugation, washing, and drying with air blast, the metal-organic framework Ⅱ-coated metal sulfur-selenium complex (metal sulfur-selenium complex@Ⅱ) is obtained;

[0068] (4) Mix 0.5 mmol of tellurium powder into the metal sulfur-selenium complex@Ⅱ, grind it evenly, place it in a quartz porcelain boat, and transfer the quartz porcelain boat to a tube furnace. Under the protection of an argon-hydrogen atmosphere with a heating rate of 5 °C / min, calcine it at 600 °C for 3 h to obtain the transition metal and poor metal selenium-sulfur-tellurium complex (0.7SnS 2 / 0.3SnSe 2 )Sb 2 Te3.

[0069] (5) Take 0.5 mmol of the transition metal and poor metal selenium-sulfur-tellurium complex, disperse it fully in 50 ml of deionized water containing 30 mg of graphene oxide, stir for 1 h, sonicate for 1 h, repeat three times, and after freeze-drying, sinter it at 450 °C for 1 h in a nitrogen environment to obtain the final product transition metal and poor metal (0.7SnS 2 / 0.3SnSe 2 )Sb2 Te 3 @rGO.

[0070] The above-prepared product, acetylene black (conductive agent) and PVDF (HS V900, binder) were weighed in a mass ratio of 7:2:1, and after being fully ground, an appropriate amount of NMP was added to disperse and mix until a viscous slurry was formed. The slurry was then evenly coated on a copper foil, dried at 85°C with a blast airflow, and cut into discs with a diameter of 12 mm. The discs were assembled in an argon atmosphere glove box, with a metal sodium sheet as the counter electrode and 1 M NaPF 6 The solution (solvent EC:DEC volume ratio of 1:1) was used as the electrolyte, and glass fiber (GradeGF / F) was used as the separator to assemble a CR2032 button cell. The precursor was analyzed using a scanning electron microscope and found that the product was a small square morphology of about 80nm ( Figure 2 ). The battery cycle performance analysis found that at 25°C, at 100mAg -1 When the constant current charge and discharge test was carried out at a rate between 0.1 and 3.0 V, the initial charge capacity of the material was 514.5 mAh g -1 At 25°C, 1Ag -1 The constant current charge and discharge test was carried out in the range of 0.1-3.0V at a rate of 1.5 times. The charge capacity after 500 cycles was 341.9mAhg -1 .

[0071] Comparative Example 1

[0072] (1) Weigh 1.1508 g of zinc nitrate and dissolve it in 100 mL of methanol to form a zinc nitrate solution, weigh 1.6231 g of 2-methylimidazole and dissolve it in 100 mL of methanol to form a 2-methylimidazole solution, after fully dissolved, pour the 2-methylimidazole solution into the zinc nitrate solution, and let it stand at room temperature for 20 hours, centrifuge, wash, and air dry to obtain metal organic framework I;

[0073] (2) The metal organic framework I was dispersed in 10 ml of deionized water to form a suspension, 3.5 mmol of thioacetamide and 3.5 mmol of selenic acid were weighed and dissolved in 10 ml of deionized water to form a reaction solution, which was added to the suspension, stirred at room temperature for 5 min, and hydrothermally reacted at 300 ° C for 12 h. After the reaction was completed, the intermediate product transition metal and the metal-poor sulfur-selenium complex 0.7ZnS / 0.3ZnSe were obtained after centrifugation, washing, and drying;

[0074] (3) Take 0.5 mmol of transition metal and poor metal sulfur-selenium composite, disperse it fully in 50 ml of deionized water containing 30 mg of graphene oxide, stir for 1 h, ultrasonicate for 1 h, repeat three times, and after freeze-drying, sinter it at 450 °C for 1 h in a nitrogen environment to obtain the final product transition metal and poor metal 0.7ZnS / 0.3ZnSe@rGO.

[0075] Weigh the above-prepared product, acetylene black (conductive agent), and PVDF (HSV900, binder) according to the mass ratio of 7:2:1 respectively. After fully grinding, add an appropriate amount of NMP to disperse and mix them until a viscous paste is formed. Then, evenly coat the paste on the copper foil. After drying at 85 °C with blowing, cut it into circular pieces with a diameter of 12 mm, and assemble it in a glove box under an argon atmosphere. Use a sodium metal sheet as the counter electrode, 1 M NaPF 6 solution (the volume ratio of the solvent EC:DEC is 1:1) as the electrolyte, and use glass fiber (Grade GF / F) as the separator to assemble a CR2032 type button cell. At 25 °C, when performing a constant current charge-discharge test at a rate of 100 mAg -1 between 0.1 - 3.0 V, the initial charge capacity of the material is 460.2 mAhg -1 . At 25 °C, perform a constant current charge-discharge test at a rate of 1 Ag -1 in the range of 0.1 - 3.0 V. After 500 cycles, the charge specific capacity is 210.6 mAhg -1 .

[0076] Table 1: Comparison data of battery performance of Examples 1 - 5 and Comparative Example 1

[0077]

[0078] Table 2: Comparison chart of resistance values and ion diffusion coefficients of Example 1 and Comparative Example 1

[0079]

[0080] As can be seen from Table 1, both the initial charge capacity (mAh / g) and the charge specific capacity (mAh / g) after 500 cycles of this application are greater than those of Comparative Example 1. Figure 3 This is the impedance diagram of the products prepared in Example 1 and Comparative Example 1 of the present invention. As Figure 3 can be seen, the impedance value of Example 1 is significantly smaller than that of Comparative Example 1, significantly improving the electronic conductivity of the material. Table 2 is the comparison chart of resistance values and ion diffusion coefficients of Example 1 and Comparative Example 1. As can be seen from Table 2, the resistance value of the product prepared in Example 1 is significantly smaller, and the ionic conductivity is significantly larger, significantly improving the ion diffusion rate and reaction kinetics of the material.

[0081] Comparative Example 2

[0082] (1) Weigh 1.1508 g of zinc nitrate and dissolve it in 100 mL of methanol to form a zinc nitrate solution. Weigh 1.6231 g of 2-methylimidazole and dissolve it in 100 mL of methanol to form a 2-methylimidazole solution. After complete dissolution, pour the 2-methylimidazole solution into the zinc nitrate solution and let it stand at room temperature for 20 h. After centrifugation, washing, and drying with forced air, metal-organic framework Ⅰ is obtained.

[0083] (2) Disperse metal-organic framework Ⅰ in 10 mL of deionized water to form a suspension. Weigh 3.5 mmol of thioacetamide, dissolve it in 10 mL of deionized water to form a reaction solution, add it to the suspension, stir at room temperature for 5 min, and carry out a hydrothermal reaction at 300 °C for 12 h. After the reaction, after centrifugation, washing, and drying, the intermediate product transition metal and poor metal sulfide ZnS-MOF is obtained.

[0084] (3) Dissolve 0.5 mmol of transition metal and poor metal sulfide in 100 mL of antimony sulfate solution. Then add 1.6231 g of 2-methylimidazole which is dissolved in 100 mL of methanol to form a 2-methylimidazole solution. After complete dissolution, pour the 2-methylimidazole solution into the antimony sulfate solution containing 0.5 mmol of transition metal and poor metal sulfide, let it stand at room temperature for 20 h. After centrifugation, washing, and drying with forced air, metal sulfide coated with metal-organic framework Ⅱ (metal sulfide@Ⅱ) is obtained.

[0085] (4) Mix 0.5 mmol of tellurium powder into metal sulfide@Ⅱ, grind it evenly, place it in a quartz boat, and transfer the quartz boat to a tube furnace. Under the protection of an argon-hydrogen atmosphere with a heating rate of 5 °C / min, calcine it at 600 °C for 3 h to obtain the transition metal and poor metal sulfur-tellurium composite ZnS / Sb 2 Te 3 -MOF.

[0086] (5) Take 0.5 mmol of transition metal and poor metal sulfur-tellurium composite, disperse it fully in 50 mL of deionized water containing 30 mg of graphene oxide, stir for 1 h, sonicate for 1 h, repeat three times, and after freeze-drying, sinter it at 450 °C for 1 h in a nitrogen environment to obtain the final product transition metal and poor metal ZnS / Sb 2 Te 3 @rGO.

[0087] Weigh the products prepared above, acetylene black (conductive agent), and PVDF (HS V900, binder) according to a mass ratio of 7:2:1 respectively. After sufficient grinding, add an appropriate amount of NMP and disperse and mix them until they become a viscous paste. Then evenly coat the paste on the copper foil. After drying at 85 °C with forced air, cut it into circular pieces with a diameter of 12 mm, and assemble it in a glove box under an argon atmosphere, using a sodium metal sheet as the counter electrode, 1 M of NaPF 6A solution (with a volume ratio of solvent EC:DEC of 1:1) was used as the electrolyte, and a glass fiber (Grade GF / F) was used as the separator to assemble a CR2032 coin cell. At 25 °C, at a rate of 100 mA g -1 during the constant current charge-discharge test between 0.1 - 3.0 V, the first charge capacity of the material was 430.1 mAh g -1 . At 25 °C, at a rate of 1 A g -1 during the constant current charge-discharge test in the range of 0.1 - 3.0 V, after 500 cycles, the charge specific capacity was 198.3 mAh g -1 .

[0088] Table 3: Comparison data of battery performance of Examples 1 - 4 and Comparative Example 2

[0089]

[0090]

[0091] As can be seen from Table 3, both the first charge capacity (mAh / g) and the charge specific capacity (mAh / g) after 500 cycles of this application are greater than those of Comparative Example 2.

[0092] Comparative Example 3

[0093] (1) Weigh 1.1508 g of zinc nitrate and dissolve it in 100 mL of methanol to form a zinc nitrate solution. Weigh 1.6231 g of 2-methylimidazole and dissolve it in 100 mL of methanol to form a 2-methylimidazole solution. After complete dissolution, pour the 2-methylimidazole solution into the zinc nitrate solution and let it stand at room temperature for 20 h. After centrifugation, washing, and drying with a blast dryer, metal-organic framework Ⅰ was obtained;

[0094] (2) Disperse metal-organic framework Ⅰ in 10 ml of deionized water to form a suspension. Weigh 3.5 mmol of selenic acid and dissolve it in 10 ml of deionized water to form a reaction solution, and add it to the suspension. Stir at room temperature for 5 min and carry out a hydrothermal reaction at 300 °C for 12 h. After the reaction, after centrifugation, washing, and drying, the intermediate product transition metal and poor metal selenide ZnSe-MOF was obtained;

[0095] (3) Take 0.5 mmol of the transition metal and poor metal selenide and dissolve it fully in 100 ml of antimony sulfate solution. Then add 1.6231 g of 2-methylimidazole which was weighed and dissolved in 100 mL of methanol to form a 2-methylimidazole solution. After complete dissolution, pour the 2-methylimidazole solution into the antimony sulfate solution containing 0.5 mmol of the transition metal and poor metal selenide, let it stand at room temperature for 20 h, and after centrifugation, washing, and drying with a blast dryer, the metal selenide coated with metal-organic framework Ⅱ (metal selenide@Ⅱ) was obtained;

[0096] (4) Mix 0.5 mmol of tellurium powder into the metal selenide @Ⅱ, grind it evenly, place it in a quartz porcelain boat, and transfer the quartz porcelain boat to a tube furnace. Under the protection of an argon-hydrogen atmosphere and at a heating rate of 5 °C / min, calcine it at 600 °C for 3 h to obtain a transition metal and poor metal selenium-tellurium composite ZnSe / Sb 2 Te 3 -MOF.

[0097] (5) Take 0.5 mmol of the transition metal and poor metal selenium-tellurium composite, disperse it fully in 50 ml of deionized water containing 30 mg of graphene oxide, stir for 1 h, sonicate for 1 h, repeat three times, and after freeze-drying, sinter it at 450 °C for 1 h in a nitrogen environment to obtain the final product transition metal and poor metal ZnSe / Sb 2 Te 3 @rGO.

[0098] Weigh the products prepared above, acetylene black (conductive agent), and PVDF (HS V900, binder) according to the mass ratio of 7:2:1, grind them fully, add an appropriate amount of NMP to disperse and mix them into a viscous paste, then evenly coat the paste on the copper foil. After drying at 85 °C with forced air, cut it into circular pieces with a diameter of 12 mm, and assemble it in a glove box with an argon atmosphere. Use a sodium metal sheet as the counter electrode, 1 M NaPF 6 solution (the volume ratio of the solvent EC:DEC is 1:1) as the electrolyte, and use glass fiber (Grade GF / F) as the separator to assemble a CR2032 type button cell. At 25 °C, when performing a constant current charge-discharge test at a rate of 100 mAg -1 between 0.1 - 3.0 V, the initial charge capacity of the material is 430.1 mAhg -1 . At 25 °C, when performing a constant current charge-discharge test at a rate of 1 Ag -1 in the range of 0.1 - 3.0 V, after 500 cycles, the charge specific capacity is 198.3 mAhg -1 .

[0099] Table 4: Comparison data of battery performance of Examples 1 - 4 and Comparative Example 3

[0100]

[0101] As can be seen from Table 4, both the initial charge capacity (mAh / g) and the charge specific capacity (mAh / g) after 500 cycles of this application are greater than those of Comparative Example 3.

[0102] Therefore, the present invention provides a composite material of transition metal and poor metal sulfur-selenium-tellurium, its preparation method and application. It not only forms a three-layer heterojunction structure, improves the ion diffusion kinetics, but also introduces telluride to further improve the reaction kinetics of the material. The negative electrode material for sodium ion battery prepared by using this composite has excellent rate performance and cycle stability performance.

[0103] In the description of this specification, the descriptions referring to the terms "one experimental example", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the experimental example or example are included in at least one experimental example or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same experimental example or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more experimental examples or examples.

[0104] Finally, it should be noted that the above experimental examples are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred experimental examples, those of ordinary skill in the art should understand that they can still modify the technical solutions of the present invention or make equivalent replacements, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a composite material of transition metal and metal-poor sulfur-selenium-tellurium, characterized in that: Its chemical formula is [(1-w)A n S m / wA p Se q ]B x Te y @rGO,A n S m Phase and A p Se q Forming a heterojunction structure, A n S m With A p Se q The mixed phase is then x Te y Phases are coated and mutually form a heterojunction structure, and particles coated with amorphous carbon are formed, wherein the particles are dispersed on the surface of reduced graphene oxide; A is one or more of Zn, Co, Sn, Fe, Bi, Mo, V, Mn and Sb, B is one or more of Zn, Co, Sn, Fe, Bi, Mo, V, Mn and Sb, and the value range of W is 0 <w<1; The following steps are involved: S1: reacting the ligand I with the metal salt solution of A to obtain the metal organic framework I; S2: performing a solvothermal reaction on the metal organic framework I obtained in step S1 with a sulfur source solution and a selenium source solution to generate a transition metal and a metal-poor sulfur-selenium complex; S3: reacting the transition metal and metal-poor sulfur-selenium complex obtained in step S2 with the metal salt solution of the coordination agents I and B to obtain the metal sulfur-selenium complex coated with the metal organic framework II; S4: calcining the metal sulfur-selenium complex coated with the metal organic framework II obtained in step S3 and tellurium powder at high temperature under an inert atmosphere to obtain a transition metal and metal-poor selenium-sulfur-tellurium complex; S5: calcining the transition metal and metal-poor selenium-sulfur-tellurium complex of step S4 and the graphene oxide diluted solution at high temperature in an inert atmosphere to obtain a transition metal and metal-poor selenium-sulfur-tellurium complex coated with graphene oxide.

2. The method for preparing a composite material of transition metal and metal-poor sulfur-selenium-tellurium according to claim 1, characterized in that: In step S1, the molar ratio of the complexing agent I and the element A in the metal salt solution of A is 1-100 mol:1 mol; the complexing agent I is one or more of 2-methylimidazole, terephthalic acid and trimesic acid; the concentration of the complexing agent I solution is 0.1-5 mol / L; the concentration of the element A in the metal salt solution of A is 0.03-0.1 mol / L.

3. The method for preparing a composite material of transition metal and metal-poor sulfur-selenium-tellurium according to claim 2, characterized in that: In step S2, the metal organic framework I is dispersed in the solvent I to form a suspension, and a solvothermal reaction is carried out with a sulfur source solution and a selenium source solution; the temperature of the solvothermal reaction is 120-300°C, and the time is 6-30h; the sulfur source is selected from one or more of thioacetamide, sodium sulfide and L-cysteine; the molar concentration of the sulfur source solution is 0.2-2mol / L, and the selenium source is selected from one or more of selenic acid, sodium selenate and sodium selenite; the molar concentration of the selenium source is 0.1-2.2mol / L; the ratio of the amount of element A to the amount of element sulfur in the transition metal and poor metal sulfur-selenium complex is 1mol:1-8mol; in the transition metal and poor metal sulfur-selenium complex, the molar ratio of sulfur to selenium is 1mol-10mol:1mol.

4. The method for preparing a composite material of transition metal and metal-poor sulfur-selenium-tellurium according to claim 3, characterized in that: In step S3, the molar ratio of the complexing agent I to the element B in the metal salt solution of B is 1-100 mol:1 mol; and the concentration of the element B in the metal salt solution of B is 0.02-0.1 mol / L.

5. The method for preparing a composite material of transition metal and metal-poor sulfur-selenium-tellurium according to claim 4, characterized in that: In step S4, high-temperature calcination is carried out in a tubular furnace at a temperature of 500-900°C, and the high-temperature treatment time is 0.5-24h. The atmosphere gas is one or more of a nitrogen-hydrogen mixed gas with a hydrogen content of 5%, an argon-hydrogen mixed gas with a hydrogen content of 5%, nitrogen, and argon.

6. The method for preparing a composite material of transition metal and metal-poor sulfur-selenium-tellurium according to claim 5, characterized in that: In the graphene oxide dilution solution of step S5, the mass ratio of transition metal and metal-poor selenium-sulfur-tellurium complex to graphene oxide is 10:1-3.

7. The method for preparing a composite material of transition metal and metal-poor sulfur-selenium-tellurium according to claim 6, characterized in that: The solvents in the solvothermal method, the metal salt solution of A and the metal salt solution of B are all selected from one or more of deionized water, ethanol, methanol, N,N-dimethylformamide and ethylene glycol.

8. Use of the composite material prepared by the method for preparing the composite material of transition metal and metal-poor sulfur-selenium-tellurium according to any one of claims 1 to 7 in energy storage batteries.

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