Composite electrode material, preparation method thereof and battery

Abstract

The invention provides a composite electrode material, a preparation method thereof and a battery. The composite electrode material comprises fibers interwoven into a network structure and an adhesion structure loaded on the surfaces of the fibers, the fibers are vanadium trioxide-carbon material fibers; the attachment structure is vanadium dodecahydrate, and the shape of the attachment structure comprises a petal shape and / or a wrinkle shape. The composite electrode material provided by the invention has abundant structural gaps, the electrochemical performance of the electrode can be effectively improved, the preparation method is simple to operate, and the obtained composite electrode material has good performance and wide application prospects.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrode materials, and particularly relates to a composite electrode material, a preparation method thereof and a battery. BACKGROUND

[0002] The currently widely used alkali metal battery has the defects of high manufacturing cost and low safety. Compared with other energy storage devices, aqueous zinc ion battery (AZIBs) has become a research hotspot of new energy storage devices due to its high safety, environmental friendliness and large reserves, and has great potential in the field of large-scale energy storage.

[0003] The positive electrode material, as a key component of the aqueous zinc ion battery, plays an irreplaceable role, and can provide important active sites for the insertion of Zn 2+ , and directly affects the performance of the battery.

[0004] At present, the positive electrode material of the aqueous zinc ion battery mainly includes manganese-based materials, vanadium-based materials, prussian blue analogues and the like. Compared with other materials, vanadium-based materials have structural diversity, and different crystal structures and micro-morphologies can significantly affect the electronic transmission and ion diffusion characteristics of the material, providing a broad space for performance control. Among them, the research of vanadium oxide is of particular significance. The crystal structure and electronic properties of vanadium oxide make it have a high theoretical specific capacity. Through accurate control of the crystal structure, the ion diffusion dynamics and electronic conduction performance of the material can be effectively improved, and the actual specific capacity and rate performance of the electrode can be further improved.

[0005] Vanadium-based materials have broad practical application prospects due to their high specific capacity (>300 mAh / g) and excellent zinc storage capacity. However, vanadium-based materials are prone to problems such as active material dissolution and structure collapse during charging and discharging, which leads to poor cycle performance of the material and difficulty in maintaining stable performance output, therefore, it is necessary to further develop vanadium-based positive electrode materials with high capacity and long cycle performance. SUMMARY

[0006] In view of the problems of poor stability and poor cycle performance of the existing vanadium-based electrode material in the repeated ion insertion and extraction process, the present application provides a composite electrode material, a preparation method thereof and a battery. By forming a composite electrode material with petal-shaped structure or crumpled structure on vanadium trioxide-carbon material fiber, the stress caused by volume change can be effectively relieved, the structural stability of the material can be improved, and excellent electrochemical performance can be achieved.

[0007] To achieve this purpose, the present application adopts the following technical solutions:

[0008] In a first aspect, the present application provides a composite electrode material, which comprises fibers interwoven in a network structure and an attached structure loaded on the surface of the fibers. The fibers are vanadium trioxide-carbon material fibers. The attached structure is twenty-four oxygen ten vanadium dodecahydrate, and the shape of the attached structure comprises petal-shaped and / or corrugated.

[0009] The composite electrode material provided by the present application uses vanadium trioxide-carbon material fibers as self-supporting materials, effectively improving the electronic conductivity of vanadium trioxide, and buffering the volume change of vanadium trioxide during charging and discharging. At the same time, petal-shaped and / or corrugated twenty-four oxygen ten vanadium dodecahydrate is attached to the surface of the vanadium trioxide-carbon material fibers. The attached structure has abundant structural gaps, which can play a buffering role and effectively improve the structural stability of the material. Moreover, the combination of twenty-four oxygen ten vanadium dodecahydrate and vanadium trioxide can realize the synergistic effect of multiple ion storage mechanisms, increase the energy density of the battery, and greatly improve the electrochemical performance of the material.

[0010] Preferably, the content of twenty-four oxygen ten vanadium dodecahydrate in the composite electrode material is 49.6-58.4wt%, for example, it can be 49.6wt%, 50.6wt%, 51.6wt%, 52.6wt%, 53.6wt%, 54.5wt%, 55.5wt%, 56.5wt%, 57.5wt% or 58.4wt%, etc., but is not limited to the listed values, and other unlisted values within the range are also applicable.

[0011] Preferably, the content of vanadium trioxide in the composite electrode material is 20.1-26.7wt%, for example, it can be 20.1wt%, 20.9wt%, 21.6wt%, 22.3wt%, 23.1wt%, 23.8wt%, 24.5wt%, 25.3wt%, 26wt% or 26.7wt%, etc., but is not limited to the listed values, and other unlisted values within the range are also applicable.

[0012] Preferably, the content of carbon material in the composite electrode material is 20.9-23.7wt%, for example, it can be 20.9wt%, 21.3wt%, 21.6wt%, 21.9wt%, 22.2wt%, 22.5wt%, 22.8wt%, 23.1wt%, 23.4wt% or 23.7wt%, etc., but is not limited to the listed values, and other unlisted values within the range are also applicable.

[0013] The content of the carbon material in the composite electrode material is preferably controlled in the above range, the carbon material can effectively improve the electron conductivity of V2O3, and meanwhile buffer the volume change of V2O3 in the charging and discharging process; reasonable control of the range of the carbon material can take into account the ion transmission path of the electrode material, and improve the conductivity of the composite electrode material.

[0014] Preferably, the diameter of the vanadium trioxide-carbon material fiber in the composite electrode material ranges from 1.2 to 4 μm, for example, can be 1.2 μm, 1.6 μm, 1.9 μm, 2.2 μm, 2.5 μm, 2.8 μm, 3.1 μm, 3.4 μm, 3.7 μm or 4 μm, etc., but is not limited to the listed values, and other unlisted values in the range are also applicable.

[0015] Preferably, the size of the attached structure in the composite electrode material ranges from 50 to 500 nm, for example, can be 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm or 500 nm, etc., but is not limited to the listed values, and other unlisted values in the range are also applicable.

[0016] In a second aspect, the present application provides a preparation method of the composite electrode material of the first aspect, the preparation method comprising the following steps:

[0017] (1) mixing vanadium trioxide-carbon material spinning precursor solution and twenty-four oxygen ten vanadium dodecahydrate, performing first heating, and electrospinning the material after the first heating to obtain a first fiber material.

[0018] (2) the first fiber material is sequentially cut, first dried, pre-oxidized and carbonized to obtain the composite electrode material.

[0019] The preparation method provided in the second aspect of the present application prepares the spinning precursor by the electrospinning process, and then goes through the pre-oxidation and carbonization processes, the twenty-four oxygen ten vanadium dodecahydrate grows in the petal-like structure and / or the wrinkle structure on the surface of the vanadium trioxide-carbon material fiber, the obtained petal-like structure and / or wrinkle structure has abundant structural gaps, which can play a buffering role and effectively improve the structural stability of the material.

[0020] Preferably, the preparation of the vanadium trioxide-carbon material spinning precursor solution in step (1) comprises: mixing polyacrylonitrile, N,N-dimethylformamide, ammonium metavanadate and oxalic acid dihydrate and performing second heating to obtain the vanadium trioxide-carbon material spinning precursor solution.

[0021] Preferably, the molar ratio of the polyacrylonitrile, N,N-dimethylformamide, ammonium metavanadate and oxalic acid dihydrate is (2~4):(35~45):1:(2~4). For example, the mole fraction of polyacrylonitrile can be 2, 2.3, 2.5, 2.7, 2.9, 3.2, 3.4, 3.6, 3.8 or 4, but is not limited to the listed values, and other values not listed in this range are also applicable. For example, the mole fraction of N,N-dimethylformamide can be 35, 37, 38, 39, 40, 41, 42, 43, 44 or 45, but is not limited to the listed values, and other values not listed in this range are also applicable. For example, the mole fraction of oxalic acid dihydrate can be 2, 2.3, 2.5, 2.7, 2.9, 3.2, 3.4, 3.6, 3.8 or 4, but is not limited to the listed values, and other values not listed in this range are also applicable.

[0022] The present application preferably controls the molar ratio of N,N-dimethylformamide to ammonium metavanadate within a reasonable range, which can effectively control the viscosity of the solution, improve the spinning performance, thereby reducing the agglomeration of the fibers and effectively reducing the shrinkage of the fibers during carbonization, and increasing the specific surface area of the composite electrode, improving the ion transport channel, and ensuring the electrochemical performance of the electrode material.

[0023] Preferably, the temperature of the second heating is 50~70℃, for example, it can be 50℃, 53℃, 55℃, 57℃, 59℃, 62℃, 64℃, 66℃, 68℃ or 70℃, but is not limited to the listed values, and other values not listed in this range are also applicable.

[0024] Preferably, the time of the second heating is 4~10h, for example, it can be 4h, 4.7h, 5.4h, 6h, 6.7h, 7.4h, 8h, 8.7h, 9.4h or 10h, but is not limited to the listed values, and other values not listed in this range are also applicable.

[0025] Preferably, the second heating is carried out under stirring.

[0026] Preferably, the stirring speed in the second heating is 300~500r / min, for example, it can be 300r / min, 323r / min, 345r / min, 367r / min, 389r / min, 412r / min, 434r / min, 456r / min, 478r / min or 500r / min, but is not limited to the listed values, and other values not listed in this range are also applicable.

[0027] Preferably, the mass ratio of the twelve hydrated twenty-four oxygen ten vanadium and the vanadium trioxide-carbon material spinning precursor liquid in step (1) is 0.02-0.028:1, for example, it can be 0.02:1, 0.021:1, 0.022:1, 0.023:1, 0.024:1, 0.025:1, 0.026:1, 0.027:1 or 0.028, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0028] Preferably, the temperature of the first heating is 50-70℃, for example, it can be 50℃, 53℃, 55℃, 57℃, 59℃, 62℃, 64℃, 66℃, 68℃ or 70℃, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0029] Preferably, the time of the first heating is 8-15h, for example, it can be 8h, 8.8h, 9.6h, 10.4h, 11.2h, 11.9h, 12.7h, 13.5h, 14.3h or 15h, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0030] Preferably, the first heating is carried out under stirring.

[0031] Preferably, the stirring speed in the first heating is 300-500r / min, for example, it can be 300r / min, 323r / min, 345r / min, 367r / min, 389r / min, 412r / min, 434r / min, 456r / min, 478r / min or 500r / min, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0032] Preferably, the preparation of the twelve hydrated twenty-four oxygen ten vanadium in step (1) comprises: mixing a vanadium pentoxide solution and ethylene glycol, and carrying out hydrothermal treatment, and then sequentially carrying out solid-liquid separation, washing and second drying to obtain the twelve hydrated twenty-four oxygen ten vanadium.

[0033] Preferably, the molar ratio of vanadium pentoxide to solvent in the vanadium pentoxide solution is 1:(600-750), for example, it can be 1:600, 1:610, 1:620, 1:630, 1:640, 1:650, 1:680, 1:700, 1:710, 1:720, 1:740 or 1:750, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0034] Preferably, the solvent is water.

[0035] Preferably, the mixing process of vanadium pentoxide and solvent is carried out by stirring, wherein the stirring speed is 500~700 r / min, for example, 500 r / min, 523 r / min, 545 r / min, 567 r / min, 589 r / min, 612 r / min, 634 r / min, 656 r / min, 678 r / min or 700 r / min, etc., but not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0036] Preferably, the molar ratio of vanadium pentoxide to ethylene glycol is 0.8 to 1.2:1, for example, it can be 0.8:1, 0.85:1, 0.89:1, 0.94:1, 0.98:1, 1.03:1, 1.07:1, 1.12:1, 1.16:1 or 1.2:1, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0037] Preferably, the mixing process of vanadium pentoxide solution and ethylene glycol is carried out by stirring, wherein the stirring speed is 400~600 r / min, for example, 400 r / min, 423 r / min, 445 r / min, 467 r / min, 489 r / min, 512 r / min, 534 r / min, 556 r / min, 578 r / min or 600 r / min, etc., but not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0038] Preferably, the mixing time of vanadium pentoxide solution and ethylene glycol is 1.5 to 3 hours, for example, 1.5 hours, 1.7 hours, 1.9 hours, 2 hours, 2.2 hours, 2.4 hours, 2.5 hours, 2.7 hours, 2.9 hours or 3 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0039] Preferably, the temperature of the hydrothermal treatment is 150~250℃, for example, it can be 150℃, 162℃, 173℃, 184℃, 195℃, 206℃, 217℃, 228℃, 239℃ or 250℃, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0040] Preferably, the hydrothermal treatment time is 12 to 20 hours, for example, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours or 20 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0041] Preferably, the solid-liquid separation includes vacuum filtration.

[0042] Preferably, the washing comprises rinsing with water and ethanol in sequence.

[0043] Preferably, the temperature of the second drying is 30-80℃, for example, it can be 30℃, 36℃, 42℃, 47℃, 53℃, 58℃, 64℃, 69℃, 75℃ or 80℃, etc., but not limited to the listed values, other values not listed in this range are also applicable.

[0044] Preferably, the time of the second drying is 15-40h, for example, it can be 15h, 18h, 21h, 24h, 27h, 29h, 32h, 35h, 38h or 40h, etc., but not limited to the listed values, other values not listed in this range are also applicable.

[0045] Preferably, the second drying is vacuum drying.

[0046] Preferably, the electrostatic voltage of the electrospinning in step (1) is 14-15kV, for example, it can be 14kV, 14.2kV, 14.3kV, 14.4kV, 14.5kV, 14.6kV, 14.7kV, 14.8kV, 14.9kV or 15kV, etc., but not limited to the listed values, other values not listed in this range are also applicable.

[0047] Preferably, the rotating speed of the drum of the electrospinning is 200-400r / min, for example, it can be 200r / min, 223r / min, 245r / min, 267r / min, 289r / min, 312r / min, 334r / min, 356r / min, 378r / min or 400r / min, etc., but not limited to the listed values, other values not listed in this range are also applicable.

[0048] Preferably, the collection distance of the electrospinning is 10-20cm, for example, it can be 10cm, 12cm, 13cm, 14cm, 15cm, 16cm, 17cm, 18cm, 19cm or 20cm, etc., but not limited to the listed values, other values not listed in this range are also applicable.

[0049] Preferably, the needle of the electrospinning is selected to be 22 gauge.

[0050] Preferably, the cutting is cut into a size of 6cm x 4.5cm.

[0051] Preferably, the temperature of the first drying is 50-100℃, for example, it can be 50℃, 56℃, 62℃, 67℃, 73℃, 78℃, 84℃, 89℃, 95℃ or 100℃, etc., but not limited to the listed values, other values not listed in this range are also applicable.

[0052] Preferably, the first drying time is 5-15h, for example, it can be 5h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h or 15h, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0053] Preferably, the first drying is vacuum drying.

[0054] Preferably, the temperature of the pre-oxidation in step (2) is 200-300℃, for example, it can be 200℃, 212℃, 223℃, 234℃, 245℃, 256℃, 267℃, 278℃, 289℃ or 300℃, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0055] Preferably, the pre-oxidation time is 0.5-2h, for example, it can be 0.5h, 0.7h, 0.9h, 1h, 1.2h, 1.4h, 1.5h, 1.7h, 1.9h or 2h, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0056] Preferably, the carbonization in step (2) is carried out in a protective atmosphere.

[0057] Preferably, the protective atmosphere includes any one or a combination of at least two of argon, helium or nitrogen, wherein a typical but non-limiting combination is a combination of argon and helium, a combination of nitrogen and helium, a combination of argon and nitrogen.

[0058] Preferably, the carbonization temperature is 600-900℃, for example, it can be 600℃, 612℃, 679℃, 713℃, 758℃, 783℃, 825℃, 864℃, 883℃ or 900℃, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0059] The present application preferably controls the carbonization temperature in the above range, which can ensure the complete carbonization of the electrode material fiber, ensure the number of active sites of the electrode material, and improve the electrochemical performance of the electrode material; at the same time, it can effectively avoid the fracture of the electrode material fiber at high temperature.

[0060] Preferably, the carbonization time is 0.5-4h, for example, it can be 0.5h, 0.9h, 1.3h, 1.7h, 2.1h, 2.5h, 2.9h, 3.3h, 3.7h or 4h, etc., but not limited to the listed values, other values not listed in the range are also applicable.

[0061] The present application has no special restriction on the solid-liquid separation in the above process, any device and method known to those skilled in the art for solid-liquid separation can be used, and the actual process can also be adjusted, for example, it can be filtration, centrifugal or sedimentation separation, etc., or a combination of different methods.

[0062] The present application also has no special restriction on the drying in the above process, any device and method known to those skilled in the art for drying can be used, and the actual process can also be adjusted, for example, it can be air drying, vacuum drying, drying or freeze drying, etc., or a combination of different methods.

[0063] As a preferred technical solution of the present application, the preparation method comprises the following steps:

[0064] (1) mixing polyacrylonitrile, N,N-dimethylformamide, ammonium metavanadate and oxalic acid dihydrate according to a molar ratio of (2-4):(35-45):1:(2-4), heating and stirring at 50-70℃ and 300-500r / min for 4-10h to obtain a vanadium trioxide-carbon material spinning precursor solution;

[0065] dissolving vanadium pentoxide in water according to a molar ratio of vanadium pentoxide to water of 1:(600-750), stirring at 500-700r / min during the dissolution process, obtaining a vanadium pentoxide aqueous solution; then mixing the vanadium pentoxide aqueous solution and ethylene glycol according to a molar ratio of vanadium pentoxide to ethylene glycol of 0.8-1.2:1, stirring at 400-600r / min for 1.5-3h, then hydrothermal treatment at 150-250℃ for 12-20h, then sequentially filtering, washing and vacuum drying at 30-80℃ for 15-40h to obtain twenty-four oxygen ten vanadium dodecahydrate;

[0066] mixing the vanadium trioxide-carbon material spinning precursor solution and the twenty-four oxygen ten vanadium dodecahydrate according to a mass ratio of twenty-four oxygen ten vanadium dodecahydrate to vanadium trioxide-carbon material spinning precursor solution of 0.02-0.028:1, heating and stirring at 50-70℃ and 300-500r / min for 8-15h, and electrospinning the heated material, the electrospinning voltage is 14-15kV, the roller speed is 200-400r / min, the collection distance is 10-20cm, and the needle is 22 gauge, to obtain a first fiber material;

[0067] (2) cutting the first fiber material to a size of 6cm×4.5cm, vacuum drying at 50-100℃ for 5-15h, then pre-oxidizing the dried material at 200-300℃ for 0.5-2h, introducing a protective atmosphere and carbonizing at 600-900℃ for 0.5-4h to obtain the composite electrode material.

[0068] In a third aspect, the present application provides a battery comprising the composite electrode material of the first aspect.

[0069] Compared with the prior art, the present application has at least the following beneficial effects:

[0070] (1) The preparation method of the composite electrode material provided by the present application uses electrostatic spinning method to prepare self-supporting electrode material without introducing non-active materials such as binders and current collectors, which not only simplifies the electrode preparation process, avoids problems such as uneven mixing and poor adhesion during traditional coating, but also effectively improves the electrochemical performance of the electrode material.

[0071] (2) The composite electrode material provided by the present application composites vanadium trioxide and carbon material, effectively improves the electronic conductivity of vanadium trioxide, and also buffers the volume change of vanadium trioxide during charging and discharging.

[0072] (3) The composite electrode material provided by the present application composites vanadium trioxide-carbon material and vanadium trioxide-carbon material, realizes the synergistic effect of multiple ion storage mechanisms, increases the energy density of the battery, and greatly improves the electrochemical performance of the material. BRIEF DESCRIPTION OF DRAWINGS

[0073] Figure 1 Low-magnification scanning electron microscope image of the vanadium trioxide-carbon material composite electrode material prepared in Example 1.

[0074] Figure 2 High-magnification scanning electron microscope image of the vanadium trioxide-carbon material composite electrode material prepared in Example 1.

[0075] Figure 3 Low-magnification scanning electron microscope image of the vanadium trioxide-carbon material composite electrode material prepared in Comparative Example 4.

[0076] Figure 4 High-magnification scanning electron microscope image of the vanadium trioxide-carbon material composite electrode material prepared in Comparative Example 4.

[0077] Figure 5 Low-magnification scanning electron microscope image of the vanadium trioxide-carbon material composite electrode material prepared in Example 10.

[0078] Figure 6 High-magnification scanning electron microscope image of the vanadium trioxide-carbon material composite electrode material prepared in Example 10.

[0079] Figure 7Low magnification scanning electron microscope image of the twelve-hydrated twenty-four-oxygen ten-vanadium / dual vanadium trioxide-carbon material composite electrode material prepared in Example 1.

[0080] Figure 8 High magnification scanning electron microscope image of the twelve-hydrated twenty-four-oxygen ten-vanadium / dual vanadium trioxide-carbon material composite electrode material prepared in Example 1.

[0081] Figure 9 Low magnification scanning electron microscope image of the twelve-hydrated twenty-four-oxygen ten-vanadium / dual vanadium trioxide-carbon material composite electrode material prepared in Example 2.

[0082] Figure 10 High magnification scanning electron microscope image of the twelve-hydrated twenty-four-oxygen ten-vanadium / dual vanadium trioxide-carbon material composite electrode material prepared in Example 2.

[0083] Figure 11 Cycle test graph of the button cell assembled with the twelve-hydrated twenty-four-oxygen ten-vanadium / dual vanadium trioxide-carbon material composite electrode material prepared in Example 1 at different cycles.

[0084] Figure 12 Cycle test graph of the button cell assembled with the twelve-hydrated twenty-four-oxygen ten-vanadium / dual vanadium trioxide-carbon material composite electrode material prepared in Example 1 at different current densities.

[0085] Figure 13 Long cycle performance test graph of the button cell assembled with the twelve-hydrated twenty-four-oxygen ten-vanadium / dual vanadium trioxide-carbon material composite electrode material prepared in Example 1, Example 10-12 at 2.0 A / g current density.

[0086] Figure 14 Cyclic voltammetry curve graph of the twelve-hydrated twenty-four-oxygen ten-vanadium / dual vanadium trioxide-carbon material composite electrode material prepared in Example 1 at different scanning rates.

[0087] Figure 15 Logarithm graph of the different scanning rates and peak current of the twelve-hydrated twenty-four-oxygen ten-vanadium / dual vanadium trioxide-carbon material composite electrode material prepared in Example 1.

[0088] Figure 16 Diffusion contribution and capacitance contribution proportion graph of the twelve-hydrated twenty-four-oxygen ten-vanadium / dual vanadium trioxide-carbon material composite electrode material prepared in Example 1.

[0089] Figure 17 Constant current intermittent titration curve graph of the twelve-hydrated twenty-four-oxygen ten-vanadium / dual vanadium trioxide-carbon material composite electrode material prepared in Example 1 in the charging and discharging process.

[0090] Figure 18 To evaluate the diffusion coefficient of the obtained composite electrode material of twelve-hydrated twenty-four-oxygen ten-vanadium / vanadium trioxide-carbon material by Figure 17 The diffusion coefficient graph of the composite electrode material of twelve-hydrated twenty-four-oxygen ten-vanadium / vanadium trioxide-carbon material obtained by the constant current intermittent titration curve evaluation is shown in Figure 2. DETAILED DESCRIPTION

[0091] For the purpose of understanding the present application, the present application is illustrated by the following examples. It should be apparent to those skilled in the art that the examples are merely illustrative of the present application and should not be considered as limiting the present application.

[0092] It should be understood that, in the description of the present application, the terms "first", "second", etc. are used only for descriptive purposes and should not be construed as indicating or implying relative importance or implying the number of the technical features indicated. Therefore, the features defined with "first", "second", etc. can be explicitly or implicitly included one or more features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0093] In the following examples, all experimental materials and reagents, etc. can be obtained from commercial channels unless otherwise specified.

[0094] Unless otherwise specified, the specific techniques or conditions in the examples can be carried out according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0095] Example 1

[0096] The present embodiment provides a preparation method of a composite electrode material, which comprises the following steps:

[0097] (1) Polyacrylonitrile (weight average molecular weight of 100,000), N,N-dimethylformamide, ammonium metavanadate and oxalic acid dihydrate were mixed according to a molar ratio of 3:40:1:3, heated and stirred at 60℃ and 400r / min for 6h to obtain a vanadium trioxide-carbon material spinning precursor solution;

[0098] Vanadium pentoxide was dissolved in water according to a molar ratio of vanadium pentoxide to water of 1:690, and stirred at 600r / min during the dissolution process to obtain a vanadium pentoxide aqueous solution; then vanadium pentoxide aqueous solution and ethylene glycol were mixed according to a molar ratio of vanadium pentoxide to ethylene glycol of 1:1, and stirred at 500r / min for 2h, then poured into the inner liner of a polytetrafluoroethylene reaction kettle, and subjected to hydrothermal treatment at 200℃ for 16h, then sequentially subjected to suction filtration, and repeatedly washed with deionized water and anhydrous ethanol, and the filter cake was placed in a vacuum drying oven at 60℃ and 80kPa for 24h to obtain twelve-hydrated twenty-four-oxygen ten-vanadium;

[0099] The vanadium pentoxide and water were dissolved in water according to a vanadium pentoxide to water molar ratio of 1:700, and stirring was performed at 700 r / min during the dissolving process to obtain a vanadium pentoxide aqueous solution; then the vanadium pentoxide aqueous solution and the ethylene glycol were mixed according to a vanadium pentoxide to ethylene glycol molar ratio of 1.2:1 under the condition of 400 r / min and stirring for 3 h, and then poured into a polytetrafluoroethylene reactor inner liner, and subjected to hydrothermal treatment at 250℃ for 12 h; then the filter cake was subjected to vacuum drying at 30℃ and 80 kPa for 40 h after being sequentially subjected to suction filtration and repeated washing with deionized water and anhydrous ethanol to obtain the dodecahydrate of vanadium tetraoxide;

[0100] (2) The first fiber material was cut into a size of 6 cm x 4.5 cm, and vacuum dried at 80℃ and 80 kPa for 8 h, and then the dried material was placed in a muffle furnace and pre-oxidized at 240℃ for 1 h, and then argon was introduced to form an argon atmosphere and carbonized at 800℃ for 2 h to obtain the composite electrode material.

[0101] Example 2

[0102] The present embodiment provides a preparation method of a composite electrode material, which comprises the following steps:

[0103] (1) The polyacrylonitrile (with a weight average molecular weight of 100,000), N,N-dimethylformamide, ammonium metavanadate and oxalic acid dihydrate were mixed according to a molar ratio of 2:45:1:2, and heated and stirred at 50℃ and 500 r / min for 10 h to obtain a vanadium dioxide-carbon material spinning precursor solution;

[0104] The vanadium pentoxide was dissolved in water according to a vanadium pentoxide to water molar ratio of 1:700, and stirring was performed at 700 r / min during the dissolving process to obtain a vanadium pentoxide aqueous solution; then the vanadium pentoxide aqueous solution and the ethylene glycol were mixed according to a vanadium pentoxide to ethylene glycol molar ratio of 1.2:1 under the condition of 400 r / min and stirring for 3 h, and then poured into a polytetrafluoroethylene reactor inner liner, and subjected to hydrothermal treatment at 250℃ for 12 h; then the filter cake was subjected to vacuum drying at 30℃ and 80 kPa for 40 h after being sequentially subjected to suction filtration and repeated washing with deionized water and anhydrous ethanol to obtain the dodecahydrate of vanadium tetraoxide;

[0105] The vanadium pentoxide and water were dissolved in water according to a vanadium pentoxide to water molar ratio of 1:700, and stirring was performed at 700 r / min during the dissolving process to obtain a vanadium pentoxide aqueous solution; then the vanadium pentoxide aqueous solution and the ethylene glycol were mixed according to a vanadium pentoxide to ethylene glycol molar ratio of 1.2:1 under the condition of 400 r / min and stirring for 3 h, and then poured into a polytetrafluoroethylene reactor inner liner, and subjected to hydrothermal treatment at 250℃ for 12 h; then the filter cake was subjected to vacuum drying at 30℃ and 80 kPa for 40 h after being sequentially subjected to suction filtration and repeated washing with deionized water and anhydrous ethanol to obtain the dodecahydrate of vanadium tetraoxide;

[0106] (2) The first fiber material is cut to a size of 6cm×4.5cm and vacuum dried at 50℃ and 80kPa for 15h. Then the dried material is placed in a muffle furnace and pre-oxidized at 200℃ for 2h. Argon gas is then introduced and carbonized at 900℃ for 0.5h in an argon atmosphere to obtain the composite electrode material.

[0107] Example 3

[0108] This embodiment provides a method for preparing a composite electrode material, the method comprising the following steps:

[0109] (1) Polyacrylonitrile (weight average molecular weight of 100,000), N,N-dimethylformamide, ammonium metavanadate and oxalic acid dihydrate were mixed in a molar ratio of 4:35:1:4 and heated and stirred at 70℃ and 300r / min for 4h to obtain vanadium trioxide-carbon material spinning precursor solution.

[0110] Vanadium pentoxide was dissolved in water at a molar ratio of 1:650, and the solution was stirred at 500 r / min during the dissolution process to obtain an aqueous solution of vanadium pentoxide. Then, the aqueous solution of vanadium pentoxide and ethylene glycol were mixed at a molar ratio of 0.8:1 at 600 r / min and stirred for 1.5 h. The mixture was then poured into a polytetrafluoroethylene reactor liner and subjected to hydrothermal treatment at 150 °C for 20 h. The mixture was then filtered, repeatedly washed with deionized water and anhydrous ethanol, and the filter cake was dried under vacuum at 80 °C and 80 kPa for 15 h to obtain vanadium dodecyl oxide dodecahydrate.

[0111] The vanadium trioxide-carbon spinning precursor solution and the vanadium trioxide-carbon spinning precursor solution were mixed at a mass ratio of 0.02:1. The mixture was heated and stirred at 70℃ and 300 r / min for 15 h to form a homogeneous spinning solution. The heated spinning solution was then subjected to electrospinning with a static voltage of 14 kV, a roller speed of 200 r / min, a collection distance of 15 cm, and a needle size of 22 to obtain the first fiber material.

[0112] (2) The first fiber material is cut to a size of 6cm×4.5cm and vacuum dried at 100℃ and 80kPa for 5h. Then the dried material is placed in a muffle furnace and pre-oxidized at 300℃ for 0.2h. Argon gas is then introduced and carbonized at 600℃ for 4h in an argon atmosphere to obtain the composite electrode material.

[0113] Example 4

[0114] The embodiment provides a preparation method of a composite electrode material, wherein the preparation method is same with the preparation method in the embodiment 1 except that the molar ratio of polyacrylonitrile to ammonium metavanadate is 5:1.

[0115] Embodiment 5

[0116] The embodiment provides a preparation method of a composite electrode material, wherein the preparation method is same with the preparation method in the embodiment 1 except that the molar ratio of polyacrylonitrile to ammonium metavanadate is 5:1.

[0117] Embodiment 6

[0118] The embodiment provides a preparation method of a composite electrode material, wherein the preparation method is same with the preparation method in the embodiment 1 except that the molar ratio of N,N-dimethylformamide to ammonium metavanadate is 30:1.

[0119] Embodiment 7

[0120] The embodiment provides a preparation method of a composite electrode material, wherein the preparation method is same with the preparation method in the embodiment 1 except that the molar ratio of N,N-dimethylformamide to ammonium metavanadate is 50:1.

[0121] Embodiment 8

[0122] The embodiment provides a preparation method of a composite electrode material, wherein the preparation method is same with the preparation method in the embodiment 1 except that the temperature of carbonization is 400 DEG C.

[0123] Embodiment 9

[0124] The embodiment provides a preparation method of a composite electrode material, wherein the preparation method is same with the preparation method in the embodiment 1 except that the temperature of carbonization is 1200 DEG C.

[0125] Embodiment 10

[0126] The embodiment provides a preparation method of a composite electrode material, wherein the preparation method is same with the preparation method in the embodiment 1 except that the mass ratio of twenty-four oxygen ten vanadium dodecahydrate to vanadium trioxide-carbon material spinning precursor solution is 0.008:1.

[0127] Embodiment 11

[0128] The embodiment provides a preparation method of a composite electrode material, wherein the preparation method is same with the preparation method in the embodiment 1 except that the mass ratio of twenty-four oxygen ten vanadium dodecahydrate to vanadium trioxide-carbon material spinning precursor solution is 0.016:1.

[0129] Embodiment 12

[0130] This embodiment provides a method for preparing a composite electrode material. Except for the mass ratio of vanadium dodecahydrate to vanadium trioxide-carbon spinning precursor liquid being 0.032:1, the preparation method is the same as in Example 1 and will not be repeated here.

[0131] Comparative Example 1

[0132] This comparative example provides a method for preparing a composite electrode material. The preparation method is the same as in Example 1, except that vanadium dodecyl oxytetraoxide decavanadium dodecahydrate is replaced with vanadium pentoxide powder. It will not be described again here.

[0133] Comparative Example 2

[0134] This comparative example provides a method for preparing a composite electrode material. The preparation method is the same as in Example 1, except that vanadium dodecyl oxytetraoxide dodecahydrate is replaced with ammonium metavanadate. It will not be described again here.

[0135] Comparative Example 3

[0136] This comparative example provides a method for preparing a composite electrode material. Except for step (1) where polyacrylonitrile is not added, the preparation method is the same as in Example 1, and will not be repeated here.

[0137] Comparative Example 4

[0138] This comparative example provides a method for preparing a composite electrode material. Except for step (1) where no dodecyloxovanadium dodecylhydrate is added, the preparation method is the same as in Example 1, and will not be repeated here.

[0139] The composite electrode material (vanadium dodecyl tetraoxygenate dodecahydrate / vanadium trioxide-carbon composite electrode material) prepared in Example 1 was analyzed by scanning electron microscopy, and the results are as follows: Figures 1-2 As shown, the composite electrode material (vanadium trioxide-carbon composite electrode material) prepared in Comparative Example 4 was analyzed by scanning electron microscopy, and the results are as follows. Figures 3-4 As shown, from Figures 1-4 It can be seen that, compared to vanadium trioxide-carbon composite electrode materials, vanadium dodecahydrate (VdO2-O3-O3-VdO3) grows on vanadium trioxide-carbon fibers in a petal-like or wrinkled form, with a more compact and complex entanglement and bonding between the fibers. This means a larger contact area between the electrode and the electrolyte, which can improve electrochemical reaction activity, enhance the capacity performance of the electrode material, and store more charge during battery charging and discharging. The complex interweaving between the fibers forms a complete network structure, providing more channels for ion transport within the electrode material, accelerating ion diffusion, reducing internal electrode resistance, and improving charging and discharging efficiency and power density. Combining the fiber structure and the petal-like structure, the two structures support each other, better maintaining the integrity of the electrode structure during charging and discharging.

[0140] The composite electrode material (vanadium dodecyl dodecahydrate / vanadium trioxide-carbon composite electrode material, wherein the mass ratio of vanadium dodecahydrate to vanadium trioxide-carbon spinning precursor liquid is 0.008:1) prepared in Example 10 was analyzed by scanning electron microscopy, and the results are as follows: Figures 5-6 As shown. The composite electrode material (vanadium dodecyl dodecahydrate / vanadium trioxide-carbon composite electrode material, wherein the mass ratio of vanadium dodecahydrate to vanadium trioxide-carbon spinning precursor solution is 0.016:1) prepared in Example 11 was analyzed by scanning electron microscopy, and the results are as follows. Figures 7-8 As shown. The composite electrode material (vanadium dodecyl dodecahydrate / vanadium trioxide-carbon composite electrode material, wherein the mass ratio of vanadium dodecahydrate to vanadium trioxide-carbon spinning precursor solution is 0.032:1) prepared in Example 12 was analyzed by scanning electron microscopy, and the results are as follows. Figures 9-10 As shown. From Figures 1-2 as well as Figures 5-10 It can be seen that when the doping amount of dodecyloxovanadium dodecylhydrate is too low (see...) Figures 5-8 A small amount of vanadium dodecyl oxide dodecahydrate was inserted obliquely into the fiber surface, but it did not completely cover the fiber surface, resulting in a small growth range of the petal-like structure. When the doping amount of vanadium dodecahydrate powder was moderate (see...), Figures 1-2 The petal-like structure has a large growth range, and the fiber surface exhibits petal-like or wrinkled structures, with more tightly intertwined and complex fiber bonding; when the doping content of dodecyl vanadium tetraoxygenate powder is too high (see...), Figures 9-10 The fiber surface is covered by a large number of particles and a small number of flake-like dodecyl vanadium 24O3 hydrate stacked together. Many particles agglomerate, resulting in uneven fiber thickness.

[0141] Taking Example 1 as an example, the composite electrode material prepared in Example 1 was used as the positive electrode material, a 2 mol / L Zn(CF3SO3)2 solution was used as the electrolyte, zinc foil was selected as the negative electrode material, and a glass fiber separator was used. A button cell assembled in the order of positive electrode shell, spring sheet, gasket, self-supporting positive electrode material, separator, zinc foil negative electrode, and negative electrode shell was subjected to cycle tests at different numbers of revolutions and different current densities. The results are shown in the figures below. Figure 11 and Figure 12 As shown. From Figure 11 It can be seen that the charge-discharge curves of each cycle are similar in shape, indicating that it has good cycle stability. Figure 12 It can be seen that, with the continuous increase of current, except for the charge-discharge curve at 5 A / g, the charge-discharge curves at other current densities basically maintain the same shape. The cyclic curve shape at high current density indicates that the composite electrode of dodecahydrate vanadium tetrazine / vanadium trioxide-carbon material has fast charge transfer kinetics.

[0142] Referring to the preparation method of the coin cell battery, the composite electrode materials of Example 1 and Examples 10-12 were prepared into coin cell batteries, and the long cycle performance under a current density of 2.0 A / g was tested. The results are shown in Table 1. Figure 13 Figure 13 As can be seen from Table 1, the initial discharge specific capacity of the four composite electrode materials in Example 1 (V2O3 / HVO-CFC) and Examples 10-12 (corresponding to V2O3 / HVO-CFC-1, V2O3 / HVO-CFC-2 and V2O3 / HVO-CFC-3, respectively) under a current density of 2 A / g is 135.49 mAh / g, 141.92 mAh / g, 158.82 mAh / g and 132.29 mAh / g, respectively, and the discharge specific capacity after 1000 cycles is 127.19 mAh / g, 111.21 mAh / g, 131.87 mAh / g and 105.71 mAh / g, respectively. In addition, the maximum discharge specific capacity of the vanadium trioxide / twenty-four-oxygen ten vanadyl dodecahydrate-carbon material electrode is 302.49 mAh / g, and the result shows that the vanadium trioxide / twenty-four-oxygen ten vanadyl dodecahydrate-carbon material electrode has excellent long cycle performance, and the capacity retention rate after 1000 cycles is 83.03%.

[0143] Figure 14 The cyclic voltammograms of the composite electrode material of the vanadium trioxide / twenty-four-oxygen ten vanadyl dodecahydrate-carbon material prepared in Example 1 of the present application under different scanning rates are shown in Figure 2. As can be seen from the figure, all the curves have similar shapes, reflecting the characteristics of pseudo-capacitive chemical behavior.

[0144] Figure 15 The logarithmic graph of different scanning rates and peak current of the composite electrode material of the vanadium trioxide / twenty-four-oxygen ten vanadyl dodecahydrate-carbon material prepared in Example 1 of the present application is shown in Figure 3. As can be seen from the figure, the b values of peaks 1, 2, 3 and 4 are 0.79, 0.97, 0.92 and 0.82, respectively, and the b value is closer to 1.0, which indicates that the electrochemical reaction of the composite electrode material of the vanadium trioxide / twenty-four-oxygen ten vanadyl dodecahydrate-carbon material is mainly controlled by the capacitance, which explains why the composite electrode material of the vanadium trioxide / twenty-four-oxygen ten vanadyl dodecahydrate-carbon material has excellent rate performance.

[0145] Figure 16 ​The ratio of diffusion contribution and capacitance contribution of the twelve hydrated twenty-four oxygen ten vanadium / vanadium trioxide-carbon material composite electrode material prepared in Example 1 can be seen that when the scan rate is increased from 0.1 mV / s to 1.0 mV / s, the capacitance contribution ratio is increased from 88.34% to 97.37%, and the high proportion of capacitance contribution ratio is due to the design of three-dimensional self-supporting material, which effectively increases the specific surface area, facilitates the penetration of electrolyte, and facilitates the rapid transmission of electrons and ions, so that the active material can better carry out the electrochemical reaction process.

[0146] Figure 17 The constant current intermittent titration curve of the twelve hydrated twenty-four oxygen ten vanadium / vanadium trioxide-carbon material composite electrode material prepared in Example 1 of the present application in the charge and discharge process. Therefore, the Zn 2+ diffusion coefficient estimated from the constant current intermittent titration curve is

[0147] Figure 18 The diffusion coefficient of the twelve hydrated twenty-four oxygen ten vanadium / vanadium trioxide-carbon material composite electrode material evaluated by Figure 17 the constant current intermittent titration curve in the Example 1 of the present application can be seen that at a current density of 0.05 A / g, the D Zn value during the discharge process is concentrated in 10 -9 cm -2 / s to 10 -7 cm -2 / s, and as the discharge process proceeds, the D Zn value shows a downward trend, indicating that the electrostatic repulsion of the material in the charge and discharge process is enhanced, and the interface impedance between the electrode and the electrolyte will change with the discharge process. When the side reaction occurs at the interface, the impurities are adsorbed or the interface structure is changed, the interface impedance will increase.

[0148] The calculation formula in the above examples is as follows:

[0149] (1) According to the function relationship between the peak current (i) of the cyclic voltammetry curve under different scan rates and the corresponding scan rate (v), the current peak and the scan rate are fitted, the b value of the electrode material energy storage type can be judged, and the relative contribution ratio (%) of the capacitance control and the diffusion control is further calculated:

[0150] ;

[0151] ;

[0152] In the formula, a and b are adjustable parameters, i represents the peak current of the negative and positive electrodes in the CV curve, v represents the scan rate (mV / s), k1v represents the current of the capacitance control process, and k2v 1 / 2 represents the current of the diffusion control process.

[0153] (2) According to the constant current intermittent titration curve at a current density of 0.05 A / g, the zinc ion diffusion coefficient in the charge-discharge process of the battery can be calculated:

[0154] ;

[0155] In the formula, τ is the constant current pulse time; n m and V m are the molar mass and molar volume of the positive electrode, respectively; S is the contact area of the electrode and the electrolyte; ΔE s is the steady-state voltage change in a single test unit, ΔE τ is the voltage change after applying a constant current pulse in a single test unit.

[0156] Test method: The content of twenty-four oxygen ten vanadium dodecahydrate in the composite electrode material is tested by GB / T 15337-2019 "General rules for inductively coupled plasma atomic emission spectrometry", the content of vanadium trioxide in the composite electrode material is tested by GB / T 15076-2008 "General rules for X-ray fluorescence spectrometry of elements in inorganic chemical products", the content of carbon material in the composite electrode material is tested by GB / T 19587-2017 "Determination of pore size distribution and specific surface area of solid materials by gas adsorption method", the diameter range of vanadium trioxide-carbon material fiber in the composite electrode material is tested by GB / T 20032-2005 "General rules for scanning electron microscope test method", and the size of the attached structure in the composite electrode material is tested by GB / T 20032-2005 "General rules for transmission electron microscope test method".

[0157] The test results of the above examples and comparative examples are shown in Table 1.

[0158] Table 1

[0159]

[0160] The button cell is prepared by the above method, and the long cycle performance of the composite electrode material at a current density of 2.0 A / g is tested, and the capacity retention rate after 1000 cycles is calculated. The test data of the above examples and comparative examples are shown in Table 2.

[0161] Table 2

[0162]

[0163] From Table 2, the following points can be seen:

[0164] (1) From Examples 1 to 3, it can be seen that the composite electrode material provided by the application has excellent stability after being made into a button cell, and the capacity retention rate after 1000 cycles is above 81.49%;

[0165] (2) From the combination of Example 1 and Examples 4-5, it can be seen that when the molar ratio of polyacrylonitrile to ammonium metavanadate in Example 4 is 1:1, the content of carbon material is reduced, resulting in that the conductivity and structural stability of the prepared electrode material are poorer than those of Example 1. Compared with Example 1, the capacity retention rate of the material after 1000 cycles at a current density of 2.0 A / g is reduced. When the molar ratio of polyacrylonitrile to ammonium metavanadate in Example 5 is 5:1, the content of carbon material is increased, reducing the ion transmission path of the electrode material, resulting in that the conductivity of the prepared electrode material is poorer than that of Example 1. Compared with Example 1, the capacity retention rate of the material after 1000 cycles at a current density of 2.0 A / g is reduced, indicating that controlling the molar ratio of polyacrylonitrile to ammonium metavanadate within a reasonable range can significantly improve the capacity retention rate;

[0166] (3) From the combination of Example 1 and Examples 6-7, it can be seen that when the molar ratio of N,N-dimethylformamide to ammonium metavanadate in Example 6 is 30:1, the solution viscosity is too high, it is difficult to spin, the fibers are easy to agglomerate, the specific surface area of the electrode is reduced, the ion transmission channel is narrowed, resulting in that the electrochemical performance of the electrode material is reduced. Compared with Example 1, the capacity retention rate of the material after 1000 cycles at a current density of 2.0 A / g is reduced. When the molar ratio of N,N-dimethylformamide to ammonium metavanadate in Example 7 is 50:1, the solution viscosity is too low, the spun fibers are easy to break, and are not completely dried, the fibers shrink during subsequent carbonization, reducing the ion transmission path of the electrode material and reducing the performance of the electrode material. Compared with Example 1, the capacity retention rate of the material after 1000 cycles at a current density of 2.0 A / g is reduced, indicating that controlling the molar ratio of N,N-dimethylformamide to ammonium metavanadate within a reasonable range can significantly improve the capacity retention rate;

[0167] (4) From the combination of Example 1 and Examples 8-9, it can be seen that when the carbonization temperature in Example 8 is 400°C, the electrode material fibers are not completely carbonized, reducing the active sites of the electrode material, resulting in that the electrochemical performance of the material is poor. Compared with Example 1, the capacity retention rate of the material after 1000 cycles at a current density of 2.0 A / g is reduced. When the carbonization temperature in Example 9 is 1200°C, the electrode material fibers are broken seriously, reducing the ion transmission path of the electrode material, resulting in that the conductivity and stability of the material are poor. Compared with Example 1, the capacity retention rate of the material after 1000 cycles at a current density of 2.0 A / g is reduced. Thus, controlling the carbonization temperature within a reasonable range can significantly improve the capacity retention rate;

[0168] (5) In Comparative Example 1, vanadium pentoxide is used instead of dodecahydrate twenty-four oxygen ten vanadium, and vanadium pentoxide and dodecahydrate oxalic acid do not generate dodecahydrate twenty-four oxygen ten vanadium under the condition, so the prepared electrode material is not compounded with dodecahydrate twenty-four oxygen ten vanadium, resulting in that the electrode material does not have the characteristics of dodecahydrate twenty-four oxygen ten vanadium, and the electrochemical performance is poorer than that of Example 1. In Comparative Example 2, ammonium metavanadate is used instead of dodecahydrate twenty-four oxygen ten vanadium, and ammonium metavanadate and dodecahydrate oxalic acid do not generate dodecahydrate twenty-four oxygen ten vanadium under the condition, so the prepared electrode material is not compounded with dodecahydrate twenty-four oxygen ten vanadium, resulting in that the electrochemical performance of the material is poorer than that of Example 1. In Comparative Example 3, polyacrylonitrile is not added, and the prepared material is not compounded with carbon material, resulting in that the prepared electrode material has poor conductivity and structural stability. In Comparative Example 4, dodecahydrate twenty-four oxygen ten vanadium is not added, and there is no attachment structure, resulting in that the cycle capacity retention rate decreases.

[0169] The above embodiments are used to illustrate the detailed features of the present application, but the present application is not limited to the above detailed features, i.e. it does not mean that the present application must rely on the above detailed features to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of the technical features selected by the present application, addition of auxiliary technical features, selection of specific modes, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. A composite electrode material, characterized by, The composite electrode material comprises fibers interwoven in a network structure and attached structures loaded on the surface of the fibers; The fibers are vanadium trioxide-carbon material fibers; The attached structures are twenty-four-oxygen-ten-vanadium dodecahydrate, and the shapes of the attached structures comprise petal shapes and / or wrinkle shapes.

2. The composite electrode material of claim 1, wherein, The content of the twenty-four-oxygen-ten-vanadium dodecahydrate in the composite electrode material is 49.6-58.4 wt%; Preferably, the content of the vanadium trioxide in the composite electrode material is 20.1-26.7 wt%; Preferably, the content of the carbon material in the composite electrode material is 20.9-23.7 wt%; Preferably, the diameter of the vanadium trioxide-carbon material fibers in the composite electrode material ranges from 1.2 to 4 μm; Preferably, the size of the attached structures in the composite electrode material is 50-500 nm.

3. A method of producing the composite electrode material according to claim 1 or 2, characterized by, The preparation method comprises the following steps: (1) mixing vanadium trioxide-carbon material spinning precursor liquid and twenty-four-oxygen-ten-vanadium dodecahydrate, performing first heating, and electrospinning the material after the first heating to obtain first fiber material; (2) the first fiber material is sequentially subjected to cutting, first drying, pre-oxidation and carbonization to obtain the composite electrode material.

4. The production method according to claim 3, characterized by, The preparation of the vanadium trioxide-carbon material spinning precursor liquid in step (1) comprises: mixing polyacrylonitrile, N,N-dimethylformamide, ammonium metavanadate and oxalic acid dihydrate and performing second heating to obtain vanadium trioxide-carbon material spinning precursor liquid. Preferably, the molar ratio of the polyacrylonitrile, N,N-dimethylformamide, ammonium metavanadate and oxalic acid dihydrate is (2-4):(35-45):1:(2-4).

5. The production method according to claim 3 or 4, characterized by, The mass ratio of the twenty-four-oxygen-ten-vanadium dodecahydrate to the vanadium trioxide-carbon material spinning precursor liquid in step (1) is 0.02-0.028:

1.

6. The method according to any one of claims 3 to 5, wherein the compound of formula (I) is prepared by the process of claim 1 or 2. The preparation of the twenty-four-oxygen-ten-vanadium dodecahydrate in step (1) comprises: mixing vanadium pentoxide solution and ethylene glycol, and performing hydrothermal treatment, and then sequentially performing solid-liquid separation, washing and second drying to obtain twenty-four-oxygen-ten-vanadium dodecahydrate; Preferably, the molar ratio of the vanadium pentoxide to the ethylene glycol is 0.8-1.2:1; Preferably, the temperature of the hydrothermal treatment is 150-250 °C; Preferably, the time of the hydrothermal treatment is 12-20 h.

7. The method according to any one of claims 3 to 6, wherein the method further comprises the step of: The electrostatic voltage of the electrospinning in step (1) is 14-15 kV; Preferably, the rotating speed of the drum of the electrospinning is 200-400 r / min; Preferably, the collection distance of the electrospinning is 10-20 cm.

8. The method of any one of claims 3 to 7, wherein the method further comprises the step of: The temperature of the pre-oxidation in step (2) is 200-300 °C; Preferably, the time of the pre-oxidation is 0.5-2 h.

9. The method of any one of claims 3 to 7, wherein the method further comprises the step of: The carbonization in step (2) is performed in a protective atmosphere; Preferably, the temperature of the carbonization is 600-900 °C; Preferably, the time of the carbonization is 0.5-4 h.

10. A battery, characterized by The battery comprises the composite electrode material according to claim 1 or 2.

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