A tellurium selenide-polyaniline composite material and its electrochemical preparation method and energy storage application

Abstract

The present invention relates to a tellurium-selenium-polyaniline composite material and its electrochemical preparation method and energy storage application. The preparation method comprises the following steps: S1: using tellurium powder and selenium powder as raw materials, vacuum packaging after grinding and mixing, and synthesizing tellurium-selenium alloy rods by high-temperature annealing; S2: dissolving aniline solution in alkali solution to prepare an alkaline electrolyte containing aniline solution; S3: using the above-prepared tellurium-selenium alloy rod as a working electrode, calomel electrode as a reference electrode, and Pt wire as a counter electrode, in the above-prepared alkaline electrolyte containing aniline, the tellurium-selenium-polyaniline composite material is prepared by a constant voltage electrochemical method. The tellurium-selenium-polyaniline composite material is prepared by a three-electrode constant voltage electrochemical method through the selection and combination of specific process steps and process parameters, and has excellent energy storage properties. The tellurium-selenium-polyaniline composite material can be prepared into an electrode material, which is applied to energy storage, and has good application prospects and industrialization potential.

Description

Technical Field

[0001] The present invention belongs to the fields of inorganic semiconductor materials and energy materials, and specifically refers to a tellurium selenide-polyaniline composite material, an electrochemical preparation method thereof, and an application in energy storage. Background Art

[0002] As a typical representative of secondary batteries, lithium-ion batteries have become the most widely studied commercial batteries due to their advantages such as high energy density, high charge and discharge efficiency, long service life, and environmental friendliness. Currently, lithium-ion batteries have been widely used in electronic products, electric vehicles, aerospace, and other fields. The most studied lithium-ion battery currently is the ternary lithium battery, such as: LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2 、Li 2 MnO 3 ·LiMO 2 , and their theoretical capacities are 184 mA·h·g -1 、290 mA·h·g -1 respectively. The commercially available lithium-ion battery is LiCoO 2 / C, and its theoretical energy density is only 387 W·h·kg -1 , which is difficult to meet the demand for long-distance driving of electric vehicles. Therefore, it is particularly important to develop a new type of lithium battery energy storage system with high energy density, long cycle life, low cost, and environmental friendliness.

[0003] As the positive electrode material of lithium batteries, chalcogen elements have high capacity and energy density, so they are considered to be one of the most potential candidate materials for the next generation of rechargeable lithium batteries. The advantages of lithium-sulfur (Li-S) batteries are abundant sulfur reserves and low cost; however, sulfur has a fatal drawback, that is, polysulfides are generated during the reaction process, resulting in the shuttle effect, which greatly affects the performance of the battery. Although the theoretical mass capacity of lithium-selenium (Li-Se) batteries is only 675 mA·h·g -1 , which is lower than the theoretical mass capacity of Li-S (1672 mA·h·g -1 ), but compared with sulfur, the density of selenium is significantly higher, and the volume capacity of Li-Se batteries is similar to that of Li-S batteries (Li-Se: 3253 mA·h·cm -3 , Li-S: 3467 mA·h·cm -3 ), and the conductivity of selenium is much higher than that of sulfur (Se: 1×10 -3 S·m -1 , S is 5×10 -28 S·m -1 ), so selenium is also considered to be one of the ideal candidate positive electrode materials for lithium batteries. The theoretical mass capacity of tellurium element is only 429 mA·h·g-1 , but its theoretical volume capacity is also 2621mA·h·cm -3 , energy density is 823.2W·h·kg -1 , and the conductivity of tellurium is 2×10 2 S·m -1 , much higher than sulfur (5×10 -28 S·m -1 ) and selenium (1×10 -3 S·m -1 ), which helps to improve the reaction kinetics during battery charging and discharging, but the volume expansion of Li-Te batteries makes it difficult to achieve commercial promotion for the time being.

[0004] Therefore, combining the advantages of tellurium and selenium, Te x Se y Composite materials are one of the effective ways to inhibit the shuttle effect and volume expansion of materials. However, since the lattices of Te and Se are not large enough, they are easily expanded by lithium ions during the lithium insertion process, resulting in volume expansion, and polyselenide has a shuttle effect caused by dissolution. Therefore, by inserting atoms into the chalcogen element lattice, expanding the lattice parameters and forming chemical bonds, the reaction mechanism of the active material's own charge and discharge process is changed, which plays a synergistic role in inhibiting volume expansion and shuttle effect. In addition, in Te x Se y The surface of the composite material is coated with carbon material, which can significantly enhance the conductivity of the material and effectively enhance the energy storage performance of the battery material. Based on this, the inventor synthesized the tellurium selenide-polyaniline composite material by electrochemical method and tested its application in energy storage.

[0005] In recent years, tellurium-selenium co-doped composite materials with photoelectric response, excellent metal ion storage capacity and high electrochemical stability have been reported, especially for energy storage, photoelectric response and other applications, such as:

[0006] CN109748250A discloses a method for preparing a tellurium selenide nanomaterial, and the preparation method is as follows: sodium tellurite, sodium selenite and morphology control material polyvinyl pyrrolidone are added to double distilled water, mixed thoroughly, and then the pH value is adjusted to 9.4, and the resulting solution is placed in a reactor, and then a reducing agent hydrazine hydrate (25wt / %) is added, and after sealing, the reaction is carried out at 180°C for 24 hours, and the two-dimensional tellurium selenide nanomaterial is obtained by cooling and collecting by centrifugation. The material has obvious photothermal effect, high chemical stability, low toxicity, abundant raw materials, low price, and simple preparation method. However, solvents such as hydrazine hydrate are used in the preparation process, which poses certain safety hazards.

[0007] CN108394873B discloses a preparation method of a tellurium selenium cadmium material. The preparation method is as follows: Mix a certain amount of tellurium powder, cadmium powder and selenium powder according to a molar ratio of 9:10:1, and add them to a homogenizer for homogenization for 1 h; Then load the above-mentioned mixed and homogenized materials into a graphite cylinder, then put the graphite cylinder into a quartz tube, and then put the quartz tube into a vacuum sealing furnace. After the vacuum sealing furnace is evacuated, the quartz tube is sealed; Then put the sealed quartz tube into a heating furnace, and the heating furnace is heated at a heating rate of 10 °C / min to 1200 °C and kept warm for 3 h; After the heat preservation is completed, stop heating, open the furnace chamber, and cool naturally. When the temperature is lower than 60 °C, take out the tellurium selenium cadmium block. The preparation method of this material has low requirements for equipment, high product yield, simple process, can be mass-produced, and low production cost. However, a large amount of cadmium powder is used in this preparation method, there are certain safety hazards in the production process, and it is harmful to the environment to a certain extent.

[0008] CN107501830A discloses a preparation method of an erbium tellurium selenium composite-based flexible piezoelectric thin film. The preparation method is as follows: Compound aniline, erbium nitrate, lithium tellurate, sodium selenate and cellulose, and then perform high-temperature oxidation to obtain a composite metal oxide. Then disperse the composite metal oxide in a polymethyl methacrylate / silane coupling agent / acetone solution, and then use a spin coater to form a film and anneal to obtain an erbium tellurium selenium composite-based flexible piezoelectric thin film. The preparation method of this material has better technical effects. The piezoelectric coefficient of the prepared flexible piezoelectric thin film is 703 pC / N, which is more than 7 times that of conventional composite piezoelectric materials. However, a large amount of organic solvents are used in the preparation process, which has a greater impact on pollution, and the process is complex and not easy to produce.

[0009] CN112310282A discloses a preparation method of a two-dimensional narrow-bandgap bismuth tellurium selenium material. The preparation method is as follows: First, etch the Si substrate with hydrofluoric acid, and then place it in a high-temperature annealing furnace for high-temperature oxidation growth of SiO 2 layer, and then pulse laser deposit a Bi 2 Te 2.7 Se 0.3 layer on the material, and finally sputter a Pd electrode layer through a magnetron sputtering technique. This material performs well in the performance of multifunctional devices for high-efficiency information storage and processing. It is a resistive random access memory with good storage performance, low energy consumption and broader application prospects, opening up a new way for the development of device miniaturization. However, the preparation process of this material has relatively high requirements for equipment, the process is relatively complex, and relatively dangerous hydrofluoric acid is used, and the industrial application realization is relatively low and not easy to produce and use.

[0010] CN109616634A discloses a Te x Se y S zPreparation method of cathode material for lithium secondary battery. The preparation method is as follows: Through a simple one-step heat treatment method, under the spatial confinement effect of a porous carbon carrier, elemental sulfur, selenium, and / or tellurium are mutually dissolved to form a Te x Se y S z solid solution, and it is uniformly loaded into the carbon carrier framework. This material is prepared by one-step heat treatment, with a simple process, avoiding the cumbersome operations of multi-step heat treatment. However, during the mutual dissolution process of multiple materials in the preparation of this material, it is difficult to control the doping amount of the obtained substance.

[0011] As described above, many prior arts disclose tellurium-selenium composite materials co-doped with tellurium and selenium, and other metal elements (such as Cd, Bi, Er, Pd, etc.) are often introduced, and there are even materials with a large amount of other metal salts introduced, making the obtained tellurium-selenium composite materials have better photothermal effects, piezoelectric effects, and energy storage applications, etc. In addition, the synthesis process of this type of material is mostly complex, the synthesis conditions are relatively strict, and it is difficult to produce on a large scale. Moreover, its electrochemical performance needs to be further improved.

[0012] For the above reasons, it is still of great significance to develop a type of cathode material containing two or more S-group elements that is green, environmentally friendly, relatively simple in process, and has excellent electrochemical performance. In addition, this is also a research hotspot in the field of lithium batteries, which is the basis and motivation for the completion of this invention. Summary of the Invention

[0013] The purpose of the present invention is to overcome the disadvantages and deficiencies existing in the prior art, and to provide a tellurium-selenium-polyaniline composite material, its electrochemical preparation method, and its application in energy storage. The present invention uses a constant voltage electrochemical method to prepare the tellurium-selenium-polyaniline composite material, which is simple, fast, economical, and environmentally friendly. Moreover, the prepared tellurium-selenium-polyaniline composite material has the advantages of regular and controllable morphology, and has application potential and industrial value in the direction of energy storage performance.

[0014] The first object of the present invention is to provide an electrochemical preparation method of a tellurium-selenium-polyaniline composite material.

[0015] To achieve this purpose, the technical solution includes the following steps:

[0016] S1: Using tellurium powder and selenium powder as raw materials, after grinding and mixing evenly, they are vacuum packaged and synthesized into tellurium-selenium alloy rods through high-temperature annealing;

[0017] S2: Dissolve aniline solution in an alkaline solution to prepare an alkaline electrolyte containing aniline solution;

[0018] S3: Using the tellurium-selenium alloy rod prepared in S1 as the working electrode, the calomel electrode as the reference electrode, and the Pt wire as the counter electrode, in the alkaline electrolyte containing aniline solution prepared in S2, a tellurium-selenium-polyaniline composite material is prepared by a constant voltage electrochemical method.

[0019] In the electrochemical preparation method of the tellurium-selenium-polyaniline composite material of the present invention, in step S1, the mixing of tellurium powder and selenium powder, wherein the mixing mass ratio is 1-40:1, for example, it can be 1:1, 5:1, 10:1, 20:1, 30:1 or 40:1.

[0020] In the electrochemical preparation method of the tellurium-selenium-polyaniline composite material of the present invention, in step S1, the temperature of the high-temperature annealing treatment is 400-600 °C, for example, it can be 400 °C, 450 °C, 500 °C, 550 °C or 600 °C, and the most preferred is 500 °C; the annealing treatment time is 2-36 hours, for example, it can be 2 hours, 6 hours, 12 hours, 18 hours, 24 hours or 36 hours, and the most preferred is 12 hours.

[0021] In the electrochemical preparation method of the tellurium-selenium-polyaniline composite material of the present invention, in step S1, the heating rate in the high-temperature annealing treatment is 1-9 °C min -1 , for example, it can be 1 °C min -1 , 3 °C min -1 , 5 °C min -1 , 7 °C min -1 or 9 °C min -1 , and the most preferred is 5 °C min -1 .

[0022] In the electrochemical preparation method of the tellurium-selenium-polyaniline composite material of the present invention, in step S2, the drying temperature of the tellurium-selenium alloy rod is 60-120 °C, for example, it can be 60 °C, 80 °C, 100 °C or 120 °C; the drying time is 4-12 hours, for example, it can be 4 hours, 6 hours, 8 hours, 10 hours or 12 hours.

[0023] In the electrochemical preparation method of the tellurium-selenium-polyaniline composite material of the present invention, in step S2, the alkali solution is one of sodium hydroxide aqueous solution, sodium carbonate aqueous solution, sodium bicarbonate aqueous solution, sodium acetate aqueous solution, ammonia water, and the most preferred is sodium hydroxide aqueous solution.

[0024] In the electrochemical preparation method of the tellurium-selenium-polyaniline composite material of the present invention, in step S2, the concentration of the alkali solution is 0-2mol L -1 , for example, it can be 0mol L -1 , 0.5mol L -1 , 1.0mol L-1 、1.5 mol / L -1 or 2.0 mol / L -1 ,and most preferably 0.5 mol / L -1 。

[0025] In the electrochemical preparation method of the tellurium selenium-polyaniline composite material of the present invention, in step S2, the concentration of aniline is 0 - 0.4 mol / L -1 , for example, it can be 0 mol / L -1 , 0.05 mol / L -1 , 0.10 mol / L -1 , 0.15 mol / L -1 , 0.20 mol / L -1 , 0.25 mol / L -1 , 0.3 mol / L -1 , 0.35 mol / L -1 or 0.4 mol / L -1 , and most preferably 0.25 mol / L -1 。

[0026] In the electrochemical preparation method of the tellurium selenium-polyaniline composite material of the present invention, in step S3, the voltage of the constant voltage method of the three-electrode system can be set to 0.1 - 3.0 V, for example, it can be 0.2 V, 0.5 V, 0.8 V, 1.1 V, 1.4 V, 1.7 V, 2.0 V, 2.3 V, 2.6 V, or 2.9 V; the reaction time is 1 - 96 h, for example, it can be 3 hours, 6 hours, 12 hours, 24 hours, 48 hours, 72 hours or 96 hours.

[0027] In summary, for the tellurium selenium-polyaniline composite material prepared by the constant voltage electrochemistry using the three-electrode system in step S3, that is, the tellurium selenium alloy rod synthesized by high-temperature annealing in S1 above is assembled with other electrodes into a three-electrode system and reacted in the alkaline electrolyte solution system containing aniline solution prepared in S2 above under certain voltage and time conditions, thereby obtaining the tellurium selenium-polyaniline composite material of the present invention.

[0028] The second object of the present invention is to provide a tellurium selenium-polyaniline composite material, and this tellurium selenium-polyaniline composite material is denoted as Te x Se y @PANI.

[0029] The inventor of the present invention found that when using such a preparation method, a tellurium selenium-polyaniline composite material with a specific appearance (surface rod-like structure) can be obtained, and a polymer is wrapped on the surface, while when changing some of the process parameters such as the raw material dosage ratio, voltage power, reaction time, etc., a composite material with such a morphology cannot be obtained.

[0030] The third invention purpose of the present invention is to provide a tellurium selenide-polyaniline composite material for energy storage application. Through the selection and combination of specific process steps and process parameters, it can be used as a positive electrode material for battery materials, which has good application prospects and industrialization potential. The tellurium selenide-polyaniline composite material is used as a positive electrode material for batteries.

[0031] The application scheme is:

[0032] a. preparing the obtained tellurium selenide-polyaniline composite material into a tellurium selenide-polyaniline positive electrode material sheet for a button battery;

[0033] b: Assemble a button battery using the tellurium selenide-polyaniline positive electrode material sheet as the positive electrode material and Li as the negative electrode material, and perform energy storage applications.

[0034] Further setting is the a step mainly as follows:

[0035] a-1: Take the tellurium selenide-polyaniline composite material, the conductive agent and the binder in a certain proportion and grind them fully until the particles are uniform;

[0036] a-2: Add the solvent to the mixture of a-1 above, and stir thoroughly at room temperature to physically mix the samples into a uniform slurry;

[0037] a-3: Transfer the above a-2 uniform slurry to the aluminum foil, apply it evenly with a coating machine to obtain the electrode material, and transfer it to a vacuum drying oven for drying;

[0038] a-4: Cut the pole piece material dried in a-3 into round pieces and then vacuum dry them.

[0039] Further configuration is as follows:

[0040] b-1: Select a suitable button battery shell, diaphragm, the electrode material described in a-4 as the positive electrode, the lithium sheet as the counter electrode, and an electrolyte with a suitable formula;

[0041] b-2: In the glove box, stack and assemble the materials in b-1 in order, and compact the button batteries with a tablet press;

[0042] b-3: After the button battery obtained in b-2 is left to stand for activation, electrochemical performance tests and energy storage applications are performed.

[0043] Specifically, the method comprises the following steps:

[0044] Will Te x Se yThe @PANI composite material is mixed with acetylene black and PVDF to form a positive electrode material slurry, which is coated and dried to form a positive electrode material sheet, and then assembled with a CR 2025 button battery case, a Celgard 2400 separator, and a counter electrode lithium sheet into a button battery.

[0045] A further setting is that the specific steps of step a are as follows:

[0046] a-1: Take the positive electrode material Te x Se y 100 mg of @PANI, 21.4 mg of conductive agent acetylene black, and 21.4 mg of binder PVDF (polyvinylidene fluoride) are fully ground until the particles are uniform, and then transferred to a weighing bottle;

[0047] a-2: Use a pipette to drop 600 - 1000 μL of NMP (N-methylpyrrolidone) into the above mixture, and stir at room temperature for 24 h at a rotation speed of 600 r·min -1 to make the sample fully physically mixed into a slurry;

[0048] a-3: Lay the aluminum foil flat on the film coater, transfer the above stirred sample slurry onto the aluminum foil, evenly coat it, and then transfer it to a vacuum drying oven to dry for 12 h at a drying temperature of 80 °C;

[0049] a-4: Cut the dried material into round pieces and vacuum dry it again for 6 h at a drying temperature of 80 °C.

[0050] A further setting is that the specific steps of step b are as follows:

[0051] b-1: Use a CR 2025 button battery case, a Celgard 2400 separator, and a lithium sheet as the counter electrode, and use an electrolyte containing 1 mol·L -1 of LiPF 6 and a mixed solvent of EC (ethylene carbonate) / DEC (diethyl carbonate) (volume ratio 1:1) as the electrolyte;

[0052] b-2: In a glove box filled with argon (H 2 O < 0.1 ppm, O 2 < 0.1 ppm), place the positive electrode case, the positive electrode material sheet, the electrolyte, the separator, the electrolyte, the high-purity lithium sheet, the gasket, the spring piece, and the negative electrode case from bottom to top in sequence, and use a tablet press to compact the button battery;

[0053] b-3: After standing and activation, perform electrochemical performance testing.

[0054] As described above, the present invention provides an electrochemical preparation method of a tellurium selenide-polyaniline composite material and its energy storage application. The tellurium selenide-polyaniline composite material Te x Se y@PANI can be used as the positive electrode material of lithium batteries and has excellent energy storage performance. The present invention discovers that the tellurium selenium-polyaniline composite material Te x Se y @PANI has better energy storage performance with the increase of voltage, providing a new and efficient positive electrode material for lithium battery energy storage and having great application potential and industrial value in the industrial field. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, obtaining other drawings without creative efforts still belongs to the scope of the present invention.

[0056] Figure 1 Figure 1 is the low-magnification scanning electron microscope image (SEM) of the tellurium selenium-polyaniline composite material Te x Se y @PANI prepared in Example 1 of the present invention;

[0057] Figure 2 Figure 2 is the transmission electron microscope image (TEM) of the tellurium selenium-polyaniline composite material Te x Se y @PANI prepared in Example 1 of the present invention ( Figure 2 a), the energy-dispersive X-ray spectroscopy peak diagram (EDX spectrum) ( Figure 2 b), and the elemental distribution map (EDS-STEM elemental mapping) ( Figure 2 c);

[0058] Figure 3 Figure 3 is the comparison diagram of X-ray diffraction patterns (XRD) of the tellurium selenium-polyaniline composite material Te x Se y @PANI prepared in Example 1 of the present invention and Te x Se y @PANI prepared at different voltages;

[0059] Figure 4 Figure 4 is the X-ray photoelectron spectroscopy (XPS) of the tellurium selenium-polyaniline composite material Te x Se y @PANI prepared in Example 1 of the present invention;

[0060] Figure 5 Figure 5 is the tellurium selenium-polyaniline composite material Te x Se y@PANI and Te prepared at different voltages x Se y Thermogravimetric analysis comparison chart (TG) of @PANI( Figure 5 a), Differential scanning calorimetry comparison chart (DSC)( Figure 5 b), Raman comparison chart (Raman)(5c), Infrared spectrum comparison chart (IR)( Figure 5 d);

[0061] Figure 6 is the tellurium selenide-polyaniline composite material Te x Se y @PANI and Te prepared at different voltages x Se y Electrochemical performance comparison chart of @PANI: Rate performance( Figure 6 a), Cycling stability( Figure 6 b), and Te x Se y @PANI cycle stability performance and Coulomb efficiency after 2000 cycles at 0.5A cm -3 ( Figure 6 c), Te x Se y @PANI cycle stability performance and Coulomb efficiency after 500 cycles at 2.0A cm -3 ( Figure 6 d);

[0062] Figure 7 is the tellurium selenide-polyaniline composite material Te x Se y Electrochemical performance chart of @PANI: Charge and discharge curves at different rates( Figure 7 a), Cyclic voltammetry curve at a scan rate of 0.5mV·s -1 ( Figure 7 b), Figure 7 c is the tellurium selenide-polyaniline composite material Te x Se y @PANI and Te prepared at different voltages x Se y AC impedance test comparison chart of @PANI. Detailed implementation mode

[0063] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0064] Example 1

[0065] S1: Using tellurium powder and selenium powder as raw materials, synthesize a tellurium-selenium alloy rod by high-temperature annealing. The specific steps are as follows:

[0066] S1-1: Grind tellurium powder and selenium powder with a mass ratio of 10:1 for 30 min to make the particles fine and evenly mixed. Place them on a quartz tube and transfer them to a vacuum encapsulation instrument. Slowly evacuate for 30 min;

[0067] S1-2: Use a hydrogen flame torch to perform high-temperature burning on the quartz tube and vacuum encapsulate the sample;

[0068] S1-3: After vacuum encapsulation, perform high-temperature annealing in a tube furnace for 12 h. Set the annealing temperature to 500 °C and the heating rate to 5 °C·min -1 , and pass nitrogen for protection;

[0069] S1-4: After high-temperature annealing, vacuum dry the sample for 12 h. Set the drying temperature to 60 °C to obtain a tellurium-selenium alloy rod;

[0070] S2: Prepare aniline alkaline solution as the electrolyte. The specific steps are as follows:

[0071] S2-1: Dissolve 1.0 g of sodium hydroxide flake particles in 25 ml of deionized water and stir well for 30 min until completely dissolved;

[0072] S2-2: Extract 1.14 mL of aniline solution and add it to the above-prepared sodium hydroxide solution. Stir well for 1 h until completely dissolved;

[0073] S2-3: Transfer the above solution to a volumetric flask (50 mL). After volume fixation, obtain an alkaline aniline solution. The solution composition is: 0.5 mol L -1 NaOH - 0.25 mol L -1 mixed solution of aniline.

[0074] S3: Using the tellurium-selenium alloy rod as the working electrode, the calomel electrode as the reference electrode, and the Pt wire as the counter electrode in the aniline alkaline solution electrolyte, prepare a tellurium-selenium-polyaniline composite material by the constant voltage electrochemical method. The specific steps are as follows:

[0075] S3-1: Using the tellurium-selenium alloy rod as the working electrode, the calomel electrode as the reference electrode, and the Pt wire as the counter electrode, in the aniline alkaline solution electrolyte, in the i-t mode, set the voltage to 1.4 V and the reaction time to 24 h. Deposit the material on the counter electrode Pt wire;

[0076] S3-2: Wash the above-obtained material with deionized water multiple times, centrifuge, and vacuum dry for 12 h. The drying temperature is 60 °C to obtain a tellurium-selenium-polyaniline composite material Te x Se y @PANI, denoted as M1;

[0077] S4: Preparation of tellurium selenide-polyaniline positive electrode material sheet for button battery, the specific steps are as follows:

[0078] S4-1: Take positive electrode material Te x Se y @PANI 100mg, conductive agent acetylene black 21.4mg, binder PVDF (polyvinylidene fluoride) 21.4mg, fully grind until the particles are uniform, and transfer to a weighing bottle;

[0079] S4-2: Use a pipette to add 600-1000 μL NMP (N-methylpyrrolidone) to the above mixture, and stir at room temperature for 24 hours at a speed of 600 r·min -1 , make the sample fully physically mixed into slurry;

[0080] S4-3: Spread the aluminum foil on the coating machine, and transfer the stirred sample slurry onto the aluminum foil. After evenly spreading, transfer it to a vacuum drying oven and dry it for 12 hours at 80°C;

[0081] S4-4: The dried material is cut into discs and vacuum dried again for 6 hours at a drying temperature of 80°C.

[0082] S5: Assemble a button battery using the above-mentioned tellurium selenide-polyaniline composite material as the positive electrode material and Li as the negative electrode material, and perform energy storage applications. The specific steps are as follows:

[0083] S5-1: CR 2025 button cell case, Celgard 2400 separator, lithium sheet as counter electrode, containing 1 mol·L -1 LiPF 6 The electrolyte and a mixed solvent of EC (ethylene carbonate) / DEC (diethyl carbonate) (volume ratio of 1:1) are used as the electrolyte;

[0084] S5-2: In a glove box filled with argon (H 2 O<0.1ppm,O 2 <0.1ppm), place the positive electrode shell, positive electrode material sheet, lithium-sulfur electrolyte, diaphragm, lithium-sulfur electrolyte, high-purity lithium sheet, gasket, shrapnel, negative electrode shell in order from bottom to top, and compact the button battery with a sheet press;

[0085] S5-3: After static activation, electrochemical performance test is performed.

[0086] Example 2-3 Investigation of synthetic voltage

[0087] Except for the tellurium selenide-polyaniline composite material M1 prepared using a voltage of 1.4V in S3, the tellurium selenide-polyaniline composite materials prepared at different voltages shown in Table 1 below. All other operations were the same as in Example 1, thus Example 2 and Example 3 were carried out, and the naming of the different composite materials obtained is shown in Table 1 below.

[0088] Table 1. Composite materials with different material components

[0089]

[0090] Microscopic Characterization

[0091] For the tellurium selenide-polyaniline composite material Te x Se y @PANI obtained in Example 1, microscopic characterizations were carried out by multiple different means, and the results are as follows:

[0092] 1. From the low-magnification scanning electron microscopy (SEM) image of Figure 1 , it can be seen that the tellurium selenide-polyaniline composite material Te x Se y @PANI has a rod-like structure with layered coatings on the surface, and the length of the rod is 400 - 600 nm.

[0093] 2. From the transmission electron microscopy (TEM) image of Figure 2 a, it can be seen that the observed sample morphology is consistent with the sample morphology observed by SEM, and the layered coatings on the rod-like structure are consistent with the SEM results.

[0094] Figure 2 b is the energy-dispersive X-ray spectroscopy (EDX) characterization of the Te x Se y @PANI component, and it can be found that the material is composed of elements such as Te, Se, C, N, and O.

[0095] Figure 2 c is the elemental distribution map of the obtained material. It can be seen from the figure that elements such as Te, Se, C, N, and O are evenly distributed on the rod-like structure, and C and N elements are distributed on the outer circle of the rod-like structure, which can prove that it is the Te x Se y material wrapped by polyaniline macromolecules.

[0096] 3. From the X-ray diffraction (XRD) pattern of Figure 3 , the two peaks that appear correspond to the Se(101) and Te(011) crystal planes respectively; in the range of 24 - 30°, compared with the three characteristic peaks of elemental Te, Te x Se y@PANI shows only one characteristic peak. The reason may be that Se atoms are doped into the Te lattice, generating defects and making the crystal form of some crystal planes deteriorate. Secondly, the peak of the Te(011) crystal plane has shifted, indicating that its lattice parameter has changed. The reason may be that Se atoms are incorporated into the Te lattice. In addition, in the product synthesized at a voltage of 1.4V, namely M1, two new XRD peaks appear at about 20°, which may be due to the formation of Te x Se y phase, thus generating new crystal planes.

[0097] 4. As can be seen from the Figure 4 X-ray photoelectron spectroscopy (XPS) pattern, elements Te, Se, N, C, and O exist in Te x Se y @PANI (M1); Figure 4 In b, the electron binding energies of the C=O bond, C-N / C=N bond, and benzene ring carbon framework C-C / C-H bond can be obtained, further proving that the polymer wrapped on the surface is polyaniline; Figure 4 From c, it can be known that Te in the composite material exists in the form of Te 6+ and Te 4+ ; Figure 4 In d, it can be obtained that there is mainly one kind of Te-Se 3d 5 / 2 bond for the Se 3d bond, indicating that part of Se is also oxidized to Se 6+ on the working electrode. From Figure 4 analysis, it can be obtained that Te x Se y @PANI can indeed be obtained by electrochemical methods. Here, both Te and Se exist in the form of positive valence states, so it may exist in the form of Te x Se y O z .

[0098] 5. From the TG characterization of the product in Figure 5 a, it can be seen from the figure that when the voltage is 0.8V (M3) and 1.1V (M2), the active material is as high as 88%, and it is also 67% at 1.4V, reflecting a high active material loading. Secondly, as the voltage increases, the amount of polyaniline polymer wrapped also increases; Figure 5 b is the DSC characterization of the Te x Se y @PANI component. Two obvious endothermic peaks appear at 251°C and 440°C respectively, proving that the Te x Se y @PANI component undergoes phase transitions at these two temperatures, corresponding to the phase transition temperatures of Se and Te respectively, thus proving that the material contains Te and Se elements; From Figure 5 c, it can be seen that 100 - 200 cm-1 Two Raman peaks appear, corresponding to the A1 and E peaks of Te, 238cm -1 and 600cm -1 、700cm -1 The three peaks of are Raman peaks of Se, which once again proves that the product contains Te and Se elements; from Figure 5 In the IR characterization of d, NH stretching vibration, CH stretching vibration, and C=C bond stretching vibration can be seen, corresponding to the benzene ring skeleton. Therefore, it can be judged that the product is Te x Se y @PANI.

[0099] Preparation Method of Battery Electrode M1

[0100] A. Take Te x Se y @PANI composite material M1, acetylene black, and PVDF are mixed in a ratio of (7:1.5:1.5) in an agate mortar and ground thoroughly until the sample is evenly mixed. After grinding, the sample is transferred to a weighing bottle, and N-methylpyrrolidone (NMP) is added dropwise as a solvent using a pipette. Stir at room temperature for 6-12 hours until uniform, so that the sample is fully physically mixed into a slurry.

[0101] B. Spread the aluminum foil on the coating machine, transfer the stirred sample slurry to the aluminum foil and evenly spread it, then transfer the entire aluminum foil material coated with slurry to a vacuum drying oven for 6-12 hours at a drying temperature of 60-120℃. Then take out the material sheet and cut it into round pieces of a certain size, and vacuum dry it again for 6-12 hours at a temperature of 60-120℃. Then take it out, weigh it, dry it and store it.

[0102] C. Use CR 2025 button battery shell, Celgard 2400 diaphragm, and lithium sheet as the counter electrode. The electrolyte contains 1 mol L -1 LiPF 6 Mixed solvent of electrolyte and ethylene carbonate (EC) / diethyl carbonate (DEC) (volume ratio of 1:1). In a glove box filled with argon (H2O<0.1ppm, O2<0.1ppm), place the positive electrode shell, positive electrode material sheet, electrolyte, diaphragm, electrolyte, high-purity lithium sheet, gasket, shrapnel, negative electrode shell from bottom to top, and compact the button battery with a tablet press. After static activation, the electrochemical performance test was carried out.

[0103] Preparation Method of Lithium Battery Electrodes M2 - M3

[0104] ​​The composite materials M1 in the above-mentioned "preparation method of lithium battery electrode M1" were respectively replaced with M2 and M3, and other operations remained unchanged. Thus, the above preparation method was repeatedly implemented, and battery electrodes using M2 and M3 were sequentially obtained, which were respectively named M2 electrode material and M3 electrode material.

[0105] Electrochemical Performance Test

[0106] 1. Figure 6 a is the rate performance test chart of M1 electrode material, M2 electrode material, and M3 electrode material

[0107] As can be seen from the figure, at a rate of 0.1 - 5.0 A cm -3 and cycling 10 times respectively, the rate performance of the material increases with the increase of voltage. Especially at 1.4 V, its rate performance is significantly higher than that at 1.1 V and 0.8 V. The reason may be the encapsulation of the conductive polymer polyaniline, which on the one hand improves the conductivity of the material, and on the other hand effectively hinders the x Se y volume expansion of the Te + @PANI component during charge and discharge. In addition, due to the formation of Te - Se bonds, the Te lattice parameter increases, enabling Li + to enter the Te lattice during discharge, effectively suppressing the volume expansion of the material during charge and discharge.

[0108] 2. Figure 6 b is the cycle performance test chart of M1 electrode material, M2 electrode material, and M3 electrode material

[0109] The Te x Se y @PANI component obtained at 1.4 V has significantly higher cycle stability than the Te x Se y @PANI component obtained at 1.1 V and 0.8 V. After cycling 1000 times at 0.5 A cm -3 , its capacity remains at 372 mA h cm -3 . Moreover, its capacity shows an upward trend during cycling. After cycling 500 times at 2.0 A cm -3 , its capacity remains at 99.8 mA h cm -3 , thus indicating that the Li - Te x Se y battery exhibits high rate performance. On the other hand, the battery capacity decay is still relatively fast, probably because there is still elemental tellurium in the material, which causes volume expansion during charge and discharge, resulting in rapid decay of the battery capacity.

[0110] 3. Figure 6 c is the cycle performance test chart of M1 electrode material

[0111] As can be seen from the figure, Te obtained at a voltage of 1.4 V x Se y @PANI component has significantly higher cycle stability than Te x Se y @PANI component obtained at voltages of 1.1 V and 0.8 V. At 0.5 A cm -3 After 1000 cycles, its capacity remains at 372 mA h cm -3 . Moreover, its capacity shows an upward trend during the cycling process.

[0112] 4. Figure 6 d is the cycle performance test diagram of the M1 electrode material

[0113] As can be seen from the figure, after 500 cycles at 2.0 A cm -3 , its capacity remains at 99.8 mA h cm -3 , indicating that the Li-Te x Se y battery exhibits high-rate performance. On the other hand, the battery capacity decays relatively quickly, probably because there is still elemental tellurium in the material, which causes volume expansion during charge and discharge, resulting in rapid decay of the battery capacity.

[0114] 5. Figure 7 a is the charge-discharge performance test diagram of the M1 electrode material

[0115] Te x Se y @PANI component can reach 586 mAh cm -3 in the first discharge at 0.1 Acm -3 .

[0116] 6. Figure 7 b is the cyclic voltammetry test diagram of the M1 electrode material

[0117] To evaluate the electrochemical performance of the Te x Se y @PANI component, with the active material loading of 1-2 mg cm -2 , the material was smeared and sliced and assembled into a button battery. The Te x Se y @PANI component obtained at 1.4 V was subjected to cyclic voltammetry test, scanned for five cycles in the voltage window range of 1-3 V, and the scan rate was 0.5 mV s -1 . As Figures 4 - 7 shown in b, the first two cathodic peaks appear at 1.75 V and 1.50 V, and these two cathodic peaks represent Li 2 Te2 / Li 2 Formation of Te and Li 2 Formation of Se. The traditional Li-Se battery only has one cathodic peak at 1.5 V, and the traditional Li-Te battery has two cathodic peaks at 1.56 V and 1.68 V. Secondly, at the anodic peak, 2.2 V appears, slightly higher than 1.82 V of a typical lithium battery. Secondly, as can be seen from 4-7a, the discharge curve presents two discharge platforms, corresponding to the two cathodic peaks in the CV respectively.

[0118] 7. Figure 7 c is the cyclic voltammetry test chart of M1 electrode material, M2 electrode material, and M3 electrode material

[0119] To compare the influence of voltage on the electrochemical performance of Te x Se y @PANI components, three Te x Se y @PANI components were subjected to AC impedance analysis at voltages of 0.8 V, 1.1 V, and 1.4 V. As can be seen from Figures 4 - 7 b, as the voltage increases, the impedance of the product decreases in turn. It can be seen from this that because the voltage increases, the amount of the surface conductive polymer coating increases, thereby increasing the conductivity of the material.

[0120] This proves that the tellurium selenide-polyaniline composite material Te x Se y @PANI of the present invention has excellent lithium storage performance and can be used in the aspect of energy storage.

[0121] In summary, as can be seen from all the above embodiments, the preparation method of the present invention obtains the tellurium selenide-polyaniline composite material Te x Se y @PANI with a unique morphology through the synergistic combination and coordination of specific process steps and process parameters, and it has good energy storage performance.

[0122] The above-disclosed are only the preferred embodiments of the present invention. Of course, the scope of the rights of the present invention cannot be limited thereby. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A tellurium selenide-polyaniline composite material, characterized in that: The composite material is prepared by an electrochemical preparation method, which comprises the following steps: S1: Tellurium powder and selenium powder are used as raw materials, which are ground and mixed evenly, then vacuum packaged, and then annealed at high temperature to synthesize tellurium-selenium alloy rods; S2: dissolving the aniline solution in the alkali solution to prepare an alkaline electrolyte containing the aniline solution; S3: Using the tellurium selenide alloy rod prepared in S1 as the working electrode, the calomel electrode as the reference electrode, and the Pt wire as the counter electrode, a tellurium selenide-polyaniline composite material was prepared by a constant voltage electrochemical method in an alkaline electrolyte containing aniline solution prepared in S2; In step S1, the mixing mass ratio of the tellurium powder to the selenium powder is 10:1; In step S1, the high temperature annealing treatment temperature is 500°C and the annealing treatment time is 12 hours; In step S1, the heating rate in the high temperature annealing treatment is 5°C min -1 ; In step S2, the alkali solution is a sodium hydroxide aqueous solution; In step S2, the concentration of sodium hydroxide in the alkaline electrolyte containing aniline solution is 0.5 mol·L -1 , aniline concentration is 0.25 mol·L -1 ; In step S3, the voltage of the constant voltage electrochemical method is set to 1.4 V, and the reaction time is 24 h.

2. An energy storage application of the tellurium selenide-polyaniline composite material as claimed in claim 1, characterized in that: The tellurium selenide-polyaniline composite material is used as the positive electrode material of the battery.

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