Nanowire structure squaric acid tellurium zinc ion battery positive electrode material and preparation method and application thereof

Abstract

The invention relates to a preparation method of a nanowire structured squaric acid tellurium zinc ion battery positive electrode material. The preparation method comprises the following steps: ultrasonically mixing tellurium dioxide and squaric acid to form white mixed dispersion liquid, and heating for pre-reaction; performing hydrothermal reaction on the mixed dispersion liquid to obtain a crude product; centrifuging, washing and drying the crude product to obtain a primary product; soaking the primary product into a zinc salt solution, stirring for reaction, and performing suction filtration and drying to obtain a final product. The invention also relates to a nanowire structured squaric acid tellurium zinc ion battery positive electrode material and application thereof in a zinc ion battery positive electrode. The nanowire structured squaric acid tellurium positive electrode material disclosed by the invention is beneficial to increasing the contact area between the tellurium positive electrode material and electrolyte, promoting electrochemical reaction kinetics, enabling the reaction of the electrode material to be more complete, improving the energy density, and avoiding the problem of cycle performance reduction caused by the change of the volume of the electrode material in the electrochemical reaction process; the prepared material has a wide application prospect in the positive electrode of the zinc ion battery, and the energy density and the cycling stability of the battery are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of positive electrode materials for zinc ion batteries, and in particular relates to a nanowire structured squarate zinc telluride positive electrode material for a battery, and a preparation method and application thereof. Background Art

[0002] In today's society, the continued consumption of traditional fossil energy sources is not only detrimental to sustainable development but also poses serious environmental pollution problems. New energy and storage systems are urgently needed. Batteries, with their efficient energy storage and conversion capabilities, have become a focus of attention this year. Lithium-ion batteries, currently the most widely used battery, have fully demonstrated their effectiveness in many areas of human life. However, lithium-ion batteries also pose certain environmental risks and pose serious safety concerns, including the risk of explosions and deflagrations. With the increasing emphasis on green development and safety, zinc-ion batteries, primarily based on aqueous electrolytes, are emerging as energy storage devices due to their low pollution, low cost, and excellent safety, attracting increasing attention. Zinc, with its abundant resources, low redox potential, safe, non-flammable, and non-toxic electrolytes, and high theoretical capacity, presents enormous potential for application.

[0003] Although zinc-ion batteries have many advantages mentioned above, the energy density of zinc-ion batteries is still a key factor restricting their practical application. The energy density of zinc-ion batteries is mainly determined by their cathode materials. For example, the commonly used MnO2 cathode material has a capacity of about 300 mAh g -1 (calculated based on the mass of the active material MnO2), and the capacity is often only 150mAh g at high rates. -1 , the overall energy density of the device is not high. While vanadium-based cathode materials have higher specific capacity, they have a smaller voltage window and often poor cycling performance. Therefore, exploring new zinc-ion battery cathode materials with superior and more comprehensive performance is extremely important for promoting the development and practical application of zinc-ion batteries.

[0004] In recent years, tellurium materials such as tellurium dioxide (TeO2) and telluride (XTe) have been attempted to be used as cathode materials in aqueous zinc-ion batteries due to their unique physical and chemical properties, and relevant research has been conducted. Taking TeO2 as an example as a cathode material, the main advantage of tellurium materials is its 6-electron reaction (Te converts between +4 and -2 valences), which has higher energy density and can effectively improve the low energy density of aqueous zinc-ion batteries, showing great potential. However, TeO2 is mostly large in size and has poor compatibility with the electrolyte. When used as a cathode material, it is often difficult to react fully, resulting in a decrease in energy density. In addition, the electrochemical reaction process is accompanied by large volume changes, causing the electrode material to fall off from the current collecting material, resulting in poor battery cycle stability.

[0005] Therefore, it is necessary to design and regulate the microstructure of TeO2 materials to improve their electrochemical performance when used as positive electrode materials. Summary of the Invention

[0006] The purpose of the present invention is to overcome the shortcomings of the existing technology, provide a nanowire structured zinc telluride cathode material and a preparation method thereof, and apply the cathode material in zinc ion batteries to improve the performance of the battery.

[0007] The present invention solves the technical problem by the following technical solutions:

[0008] A method for preparing a nanowire structured squarate zinc telluride battery cathode material, the method comprising the following steps:

[0009] S1. Taking an appropriate amount of tellurium dioxide and squaric acid solid powder and dispersing them in an appropriate amount of deionized water, ultrasonically treating them to form a white mixed dispersion, and heating the obtained mixed dispersion for pre-reaction;

[0010] S2, transferring the mixed dispersion heated in S1 to a hydrothermal reactor, controlling the ratio of the total volume of the dispersion to the volume of the reactor, and simultaneously controlling the reaction temperature and the reaction time to perform a hydrothermal reaction to obtain a crude product;

[0011] S3, centrifuging the crude product, vacuum filtering it with a Buchner funnel and filter membrane, washing it with distilled water, and heating and drying it in an oven to obtain a preliminary product;

[0012] S4. Prepare a zinc salt solution of a certain concentration, immerse the preliminary product obtained in S3 in the zinc salt solution and stir, filter after stirring, wash with a small amount of alcohol, heat, dry and grind to obtain a nanowire structured square zinc telluride ion battery positive electrode material.

[0013] Moreover, the molar concentration of tellurium dioxide and squaric acid in the mixed dispersion of S1 is 0.5 to 1 mol / L, and the concentration ratio is 1:1 to 1:3.

[0014] Moreover, the pre-reaction temperature of S1 is 90-95° C., and the pre-reaction time is 3-6 hours.

[0015] Moreover, the total volume of the dispersion in S2 is 20% to 40% of the total volume of the reactor, the hydrothermal reaction temperature is 120 to 150° C., and the hydrothermal reaction time is 12 to 18 hours.

[0016] Moreover, the centrifugal speed of S3 is 6000 rpm, and the centrifugal time is 12 min.

[0017] Moreover, the zinc salt of S4 is any one of zinc sulfate, zinc chloride, zinc tetrafluoroborate, and zinc trifluoromethanesulfonate, the concentration of the zinc salt solution is 1-2 mol / L, and the stirring time is 24 h.

[0018] A nanowire structured squarate zinc telluride ion battery positive electrode material is prepared by adopting the method.

[0019] The invention discloses an application of a nanowire structured zinc telluride ion battery positive electrode material prepared by the method in a zinc ion battery positive electrode, wherein the nanowire structured zinc telluride ion battery positive electrode material is mixed with Ketjen black and polyvinylidene fluoride in a mass ratio of 7:2:1 and ground evenly, and N-methylpyrrolidone is added to a suitable viscosity, and the obtained viscous dispersion is heated at a temperature of 3 mg / cm 2 The loading amount was evenly coated on the conductive carbon cloth, dried at 60°C in a vacuum oven for 12 h, and then cut into discs with a diameter of 10 mm to prepare the positive electrode material pole piece.

[0020] The advantages and beneficial effects of the present invention are:

[0021] 1. The nanowire-structured positive electrode material of the present invention can provide a larger contact area between the electrode material and the electrolyte, resulting in a more complete electrochemical reaction and avoiding the problem of slow and uneven reaction kinetics within the bulk electrode material. At the same time, the nanowire structure can also avoid the capacity decay caused by volume change during the electrochemical reaction. The zinc ion battery prepared with this positive electrode material can have a higher specific capacity and better cycle stability.

[0022] 2. The cathode material prepared by the present invention is a new tellurium-based cathode material, which is beneficial for obtaining a zinc-ion battery cathode with higher energy density by promoting the electrochemical reaction of tellurium, thereby improving the energy density of the zinc-ion battery.

[0023] 3. The present invention prepares a new cathode material with a nanowire structure from tellurium materials such as tellurium dioxide, which are usually large block structures. This unique structure is conducive to increasing the electrochemical reaction area of ​​the tellurium cathode material and enhancing the diffusion kinetics, while avoiding the problem of difficulty in rapid and complete reaction inside the bulk tellurium material.

[0024] 4. The tellurium squarate cathode material with a unique nanowire structure prepared by the present invention has battery characteristics such as high discharge specific capacity and high cycle stability when used as the positive electrode of zinc ion batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a scanning electron microscope image of the tellurium dioxide and squaric acid raw materials used in the present invention;

[0026] Figure 21 is a scanning electron microscope image of different positions of the nanowire structured squarate zinc telluride ion battery positive electrode material prepared in Example 2 of the present invention;

[0027] Figure 3 This is a transmission electron microscope image of the nanowire structured squarate zinc telluride ion battery positive electrode material prepared in Example 2 of the present invention;

[0028] Figure 4 This is a scanning electron microscope image of the nanowire structured squarate zinc telluride ion battery positive electrode material prepared in Example 4 of the present invention;

[0029] Figure 5 1 is an X-ray diffraction pattern of the nanowire structured squarate zinc telluride ion battery positive electrode material and raw materials prepared in Example 2 of the present invention;

[0030] Figure 6 1 is a cyclic voltammetry curve of the zinc ion battery of the positive electrode material prepared in Example 2 of the present invention and Comparative Example 1;

[0031] Figure 7 1 is a charge and discharge curve diagram of the zinc ion battery of the positive electrode materials prepared in Example 2 of the present invention and Comparative Example 1;

[0032] Figure 8 This is a comparison chart of the cycle stability of zinc ion batteries using the positive electrode materials prepared in Example 2 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below through specific examples. The following examples are only illustrative and not restrictive, and the scope of protection of the present invention cannot be limited thereto.

[0034] Example 1

[0035] (1) Add 3.19 g of tellurium dioxide and 1.14 g of squaric acid solid powder to a 50 mL beaker and disperse in 20 mL of water. Ultrasonicate the mixture for 30 min and heat to 90°C for 3 h for a pre-reaction.

[0036] (2) The mixed dispersion obtained in step (1) was transferred to a 50 mL hydrothermal reactor. The oven was preheated to 150°C and maintained for 10 min, and then the reactor was placed in the reactor for hydrothermal reaction for 12 h.

[0037] (3) The crude product obtained from the hydrothermal reaction in step (2) was centrifuged at a speed of 6000 rpm for 12 min, and the centrifuged product was filtered using a Buchner funnel and a polyamide filter membrane, washed with distilled water, and dried in an oven at 60° C. to obtain a preliminary product.

[0038] (4) Prepare 20 mL of 2 mol / L zinc sulfate solution, soak the preliminary product obtained in step (3) in the zinc salt solution, and stir under magnetic stirring for 24 hours. After stirring, filter again and wash with a small amount of alcohol, heat, dry and grind to obtain the final product.

[0039] Example 2

[0040] (1) Add 3.19 g of tellurium dioxide and 2.28 g of squaric acid solid powder to a 50 mL beaker and disperse in 20 mL of water. Ultrasonicate the mixture for 30 min and heat to 90°C for 3 h for a pre-reaction.

[0041] (2) The mixed dispersion obtained in step (1) was transferred to a 50 mL hydrothermal reactor. The oven was preheated to 150°C and maintained for 10 min, and then the reactor was placed in the reactor for hydrothermal reaction for 12 h.

[0042] (3) The crude product obtained from the hydrothermal reaction in step (2) was centrifuged at a speed of 6000 rpm for 12 min, and the centrifuged product was filtered using a Buchner funnel and a polyamide filter membrane, washed with distilled water, and dried in an oven at 60° C. to obtain a preliminary product.

[0043] (4) Prepare 20 mL of 2 mol / L zinc sulfate solution, soak the preliminary product obtained in step (3) in the zinc salt solution, and stir under magnetic stirring for 24 hours. After stirring, filter again and wash with a small amount of alcohol, heat, dry and grind to obtain the final product.

[0044] Application Examples

[0045] An aqueous zinc-ion battery, wherein the positive electrode material is the tellurium squarate positive electrode material having a nanowire structure obtained in Example 2. The tellurium squarate positive electrode material is mixed with Ketjen black and polyvinylidene fluoride in a mass ratio of 7:2:1 and ground uniformly. N-methylpyrrolidone is added until the viscosity is appropriate. The resulting viscous dispersion is evenly coated on a conductive carbon cloth with a loading of approximately 3 mg / cm 2 After drying in a vacuum oven at 60°C for 12 hours, the material was cut into 10mm diameter discs to prepare the positive electrode material. The prepared positive electrode sheet was assembled in the following order: positive electrode shell - positive electrode - glass fiber separator (with zinc salt electrolyte added) - negative electrode - gasket - spring - negative electrode shell to prepare a zinc ion battery.

[0046] Example 3

[0047] (1) Add 3.19 g of tellurium dioxide and 2.28 g of squaric acid solid powder to a 50 mL beaker and disperse in 20 mL of water. Ultrasonicate the mixture for 30 min and heat to 90°C for 3 h for a pre-reaction.

[0048] (2) The mixed dispersion obtained in step (1) was transferred to a 50 mL hydrothermal reactor. The oven was preheated to 150°C and maintained for 10 min, and then the reactor was placed in the reactor for hydrothermal reaction for 18 h.

[0049] (3) The crude product obtained from the hydrothermal reaction in step (2) was centrifuged at a speed of 6000 rpm for 12 min, and the centrifuged product was filtered using a Buchner funnel and a polyamide filter membrane, washed with distilled water, and dried in an oven at 60° C. to obtain a preliminary product.

[0050] (4) Prepare 20 mL of 2 mol / L zinc sulfate solution, soak the preliminary product obtained in step (3) in the zinc salt solution, and stir under magnetic stirring for 24 hours. After stirring, filter again and wash with a small amount of alcohol, heat, dry and grind to obtain the final product.

[0051] Example 4

[0052] (1) Add 3.19 g of tellurium dioxide and 2.28 g of squaric acid solid powder to a 50 mL beaker and disperse in 20 mL of water. Ultrasonicate the mixture for 30 min and heat to 90°C for 3 h for a pre-reaction.

[0053] (2) The mixed dispersion obtained in step (1) was transferred to a 50 mL hydrothermal reactor. The oven was preheated to 120°C and maintained for 10 min, and then the reactor was placed in the reactor for hydrothermal reaction for 12 h.

[0054] (3) The crude product obtained from the hydrothermal reaction in step (2) was centrifuged at a speed of 6000 rpm for 12 min, and the centrifuged product was filtered using a Buchner funnel and a polyamide filter membrane, washed with distilled water, and dried in an oven at 60° C. to obtain a preliminary product.

[0055] (4) Prepare 20 mL of 2 mol / L zinc sulfate solution, soak the preliminary product obtained in step (3) in the zinc salt solution, and stir under magnetic stirring for 24 hours. After stirring, filter again and wash with a small amount of alcohol, heat, dry and grind to obtain the final product.

[0056] Comparative Example 1

[0057] (1) Add 3.19 g of tellurium dioxide solid powder to a 50 mL beaker and then add 20 mL of water for dispersion. Ultrasonicate the mixture for 30 min and then heat to 90°C for 3 h.

[0058] (2) The mixed dispersion obtained in step (1) was transferred to a 50 mL hydrothermal reactor. The oven was preheated to 150°C and maintained for 10 min, and then the reactor was placed in the reactor for hydrothermal reaction for 12 h.

[0059] (3) The crude product obtained from the hydrothermal reaction in step (2) was centrifuged at a speed of 6000 rpm for 12 min, and the centrifuged product was filtered using a Buchner funnel and a polyamide filter membrane, washed with distilled water, and dried in an oven at 60° C. to obtain a preliminary product.

[0060] (4) Prepare 20 mL of 2 mol / L zinc sulfate solution, soak the preliminary product obtained in step (3) in the zinc salt solution, and stir under magnetic stirring for 24 hours. After stirring, filter again and wash with a small amount of alcohol, heat, dry and grind to obtain the final product.

[0061] The raw materials of tellurium dioxide and squaric acid as well as the prepared nanowire structured squaric acid tellurium cathode materials were characterized using an S-4800 cold field emission scanning electron microscope, and their scanning electron microscope images were obtained, as shown in the following figure: Figure 1 As shown, (a) is tellurium dioxide and (b) is squaric acid. It can be seen that the initial tellurium dioxide and squaric acid are both irregular and large-sized blocks.

[0062] And as Figure 2 As shown in the scanning electron microscope images at two different positions, the tellurium squarate cathode material prepared using the method of Example 2 of the present invention has significantly different nanowire structures and is significantly smaller in size. This unique microstructure facilitates more complete contact between the cathode material and the electrolyte, promotes the electrochemical reaction kinetics, and enables the cathode material to react fully. At the same time, such a microstructure can also avoid problems such as electrode material damage and shedding caused by volume changes before and after the electrochemical reaction process, thereby improving the cycle stability of the battery.

[0063] The microstructure of the prepared nanowire-structured tellurium squarate cathode material was further characterized using a JEM-2100F transmission electron microscope. Figure 3 As shown, the unique structure of the nanowires of the tellurium squarate cathode material prepared in Example 2 can be further demonstrated.

[0064] Figure 4 This is a scanning electron microscope image of the nanowire-structured tellurium squarate cathode material prepared in Example 4. It can be seen that compared to Example 2, although Example 4 also obtained a nanowire structure, the structure of the nanowires is less distinct, which may be due to the lower reaction temperature in Example 4.

[0065] The main raw materials used in Example 2, namely tellurium dioxide and squaric acid, were characterized using a D8 Advanced X-ray diffractometer. Figure 5 As shown, new characteristic peaks appeared in Example 2, and the peak proportions also changed significantly, which also confirmed the transformation of the structure of the obtained positive electrode material.

[0066] The cyclic voltammetry curves of the zinc ion battery using the materials prepared in Example 2 and Comparative Example 1 as the positive electrode were characterized using an electrochemical workstation CHI660e. Figure 6 As shown, compared with Comparative Example 1, the cyclic voltammetry curve area of ​​the nanowire-structured tellurium squarate positive electrode material prepared in Example 2 is larger and the shift of the peak position is smaller, which shows that thanks to this unique nanowire structure, the electrochemical reaction proceeds more fully and exhibits faster kinetics.

[0067] The charge and discharge performance of the zinc ion battery using the materials prepared in Example 2 and Comparative Example 1 as the positive electrode was characterized using Neware BTS-5V10mA battery testing equipment. Figure 7 As shown, thanks to the unique nanowire structure of the tellurium squarate cathode of Example 2, the zinc ion battery assembled in Example 2 has a higher discharge specific capacity than that of Comparative Example 1. -1 The current density can reach nearly 500mAh g -1 , which is significantly higher than that of the zinc ion battery in Comparative Example 1. This result is also consistent with the above-mentioned cyclic voltammetry curve results.

[0068] The cycling stability of the zinc ion batteries using the materials prepared in Example 2 and Comparative Example 1 as the positive electrodes was characterized using a Neware BTS-5V10mA battery testing device. Figure 8 As shown, it can be clearly seen that the specific capacity of Example 2 remains stable in continuous cycles, and the cycle stability is significantly better than that of Comparative Example 1. This is due to the effective alleviation of the volume expansion problem during the charge and discharge process of the electrode by the unique nanowire structure.

[0069] Although the embodiments and drawings of the present invention are disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A method for preparing a nanowire structured squarate zinc telluride battery cathode material, characterized by: The steps of the method are: S1. Taking an appropriate amount of tellurium dioxide and squaric acid solid powder and dispersing them in an appropriate amount of deionized water, ultrasonically treating them to form a white mixed dispersion, and heating the obtained mixed dispersion for pre-reaction; S2, transferring the mixed dispersion heated in S1 to a hydrothermal reactor, controlling the ratio of the total volume of the dispersion to the volume of the reactor, and simultaneously controlling the reaction temperature and the reaction time to perform a hydrothermal reaction to obtain a crude product; S3, centrifuging the crude product, vacuum filtering it with a Buchner funnel and filter membrane, washing it with distilled water, and heating and drying it in an oven to obtain a preliminary product; S4. Prepare a zinc salt solution of a certain concentration, immerse the preliminary product obtained in S3 in the zinc salt solution and stir, filter after stirring, wash with a small amount of alcohol, heat, dry and grind to obtain a nanowire structured square zinc telluride ion battery positive electrode material.

2. The method for preparing the nanowire structured squarate zinc telluride battery cathode material according to claim 1, characterized in that: The molar concentration of tellurium dioxide and squaric acid in the mixed dispersion of S1 is 0.5 to 1 mol / L, and the concentration ratio is 1:1 to 1:

3.

3. The method for preparing the nanowire structured squarate zinc telluride battery cathode material according to claim 1, characterized in that: The pre-reaction temperature of S1 is 90-95° C., and the pre-reaction time is 3-6 hours.

4. The method for preparing the nanowire structured squarate zinc telluride battery cathode material according to claim 1, characterized in that: The total volume of the dispersion in S2 is 20% to 40% of the total volume of the reactor, the hydrothermal reaction temperature is 120 to 150° C., and the hydrothermal reaction time is 12 to 18 hours.

5. The method for preparing the nanowire structured squarate zinc telluride battery cathode material according to claim 1, characterized in that: The centrifugal speed of S3 is 6000 rpm, and the centrifugal time is 12 min.

6. The method for preparing the nanowire structured squarate zinc telluride battery cathode material according to claim 1, characterized in that: The zinc salt of S4 is any one of zinc sulfate, zinc chloride, zinc tetrafluoroborate, and zinc trifluoromethanesulfonate. The concentration of the zinc salt solution is 1-2 mol / L, and the stirring time is 24 h.

7. A nanowire structured squarate zinc telluride battery cathode material, characterized by: The method is prepared by the method according to any one of claims 1 to 6.

8. A use of a nanowire-structured squarate zinc telluride positive electrode material prepared by the method according to any one of claims 1 to 6 in a positive electrode of a zinc ion battery, characterized in that: The nanowire structured zinc telluride ion battery cathode material was mixed with Ketjen black and polyvinylidene fluoride in a mass ratio of 7:2:1 and ground evenly. N-methylpyrrolidone was added until the viscosity was appropriate. The resulting viscous dispersion was heated to 3 mg / cm 2 The loading amount was evenly coated on the conductive carbon cloth, dried at 60°C in a vacuum oven for 12 h, and then cut into discs with a diameter of 10 mm to prepare the positive electrode material pole piece.

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