Oxygen vacancy-enriched ferric oxide silicon carbide composite material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of supercapacitors, and relates to an oxygen vacancy-rich ferric oxide silicon carbide composite material, and a preparation method and application thereof. A ferric trichloride precursor and silicon carbide nanowires are mixed and dried, melamine is dispersed on the surface of the dried material, and the ferric oxide silicon carbide composite material with oxygen vacancies is directly synthesized in air by adopting a one-step simple and rapid laser synthesis method. The synthesis method is simple, convenient and rapid, the synthesis process of the material can be completed in only a few seconds, the repeatability is high, and the material has a relatively strong industrial application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of supercapacitors, and relates to a composite material of iron oxide and silicon carbide with rich oxygen vacancies, a preparation method thereof, and an application thereof. Background Art

[0002] With the transformation of the global energy structure and the wide application of renewable energy sources (such as solar energy and wind energy), the importance of energy storage technology has become increasingly prominent. However, the intermittent characteristics of renewable energy sources, as well as the rapid development of portable electronic devices, wireless technologies, and electric vehicles, have put forward higher requirements for electrochemical energy storage devices. Although traditional lithium batteries perform excellently in terms of energy density, there are still certain limitations in aspects such as power density, cycle life, and safety. Therefore, the development of new energy storage devices has become the focus of current research. As an emerging energy storage technology, supercapacitors have quickly become a research hotspot in the field of energy storage due to their high power density, fast charge-discharge ability, and long cycle life. However, despite the excellent performance of supercapacitors in terms of power density and charge-discharge rate, their energy density and cycle stability are still insufficient, which limits their application in high-energy-demand scenarios such as electric vehicles and grid-scale energy storage systems.

[0003] To overcome these challenges, researchers have begun to explore a series of advanced materials aimed at developing next-generation energy storage devices with high energy density, high power density, excellent safety, sustainability, and cost-effectiveness. In this context, low-cost transition metal oxides have received extensive attention due to their good redox reactivity and abundant resource reserves. Among them, iron oxide (Fe2O3) has become an ideal candidate for anode materials due to its rich reserves, low cost, and impressive theoretical capacitance. Compared with other transition metal oxides, iron oxide provides a wide working potential window in the negative voltage range, showing a high theoretical specific capacitance and stable redox activity. These characteristics make it have broad application prospects in energy storage devices such as supercapacitors and lithium-ion batteries.

[0004] However, iron oxide still faces some challenges in practical applications. First, its inherent low conductivity leads to low charge transfer efficiency, which limits its performance under high-rate charge-discharge conditions. Second, significant volume expansion occurs during the charge-discharge process of iron oxide, which not only affects its structural stability but may also cause pulverization and shedding of the electrode material, thereby reducing the cycle life of the device.

[0005] The Chinese patent application document (publication number: CN116375098A) discloses a preparation method and application of an iron oxide material containing oxygen vacancies, which requires synthesizing iron oxide first and then adding melamine to generate oxygen vacancies. The synthesis process is relatively cumbersome, and the capacity decays too quickly after electrochemical testing. Summary of the Invention

[0006] The object of the present invention is to propose a composite material of iron oxide and silicon carbide with oxygen vacancies, which has excellent electrochemical performance and extremely high capacity retention rate, aiming at the above problems existing in the prior art.

[0007] The object of the present invention can be achieved by the following technical solutions:

[0008] A composite material of iron oxide and silicon carbide with oxygen vacancies, which is prepared by laser compounding of ferric chloride, silicon carbide nanowires and melamine.

[0009] The present invention also provides a preparation method of the above composite material of iron oxide and silicon carbide with oxygen vacancies, and the method comprises the following steps:

[0010] S1. Mix ferric chloride and an organic solvent fully and uniformly to obtain a ferric chloride solution;

[0011] S2. Drop the ferric chloride solution uniformly on the surface of the silicon carbide nanowires, and then dry it fully to obtain a silicon carbide nanowire material coated with ferric chloride;

[0012] S3. Then disperse melamine uniformly on the surface of the dried silicon carbide nanowire material coated with ferric chloride;

[0013] S4. Then carry out laser compounding treatment, and finally obtain the negative electrode material after washing.

[0014] In the above preparation method of a composite material of iron oxide and silicon carbide with oxygen vacancies, the organic solvent is at least one of ethanol, propanol and ethylene glycol.

[0015] Preferably, the organic solvent is ethanol with a concentration of 95-99.9 wt%. In ethanol, ferric chloride can be more uniformly dispersed, which helps it to fully contact with the reactants in the chemical reaction, improve the reaction efficiency and the uniformity of the reaction. At the same time, ethanol can stabilize the reaction system and improve the accuracy of synthesis.

[0016] In the above preparation method of a composite material of iron oxide and silicon carbide with oxygen vacancies, the concentration of ferric chloride in the ferric chloride solution in step S1 is 0.5-3 mol / L -1 .

[0017] Preferably, the concentration of ferric chloride is 0.8-1.2 mol / L -1 .

[0018] In the above preparation method of a composite material of iron oxide and silicon carbide with oxygen vacancies, the dropping amount of the ferric chloride solution in step S2 is 15-45 μL / cm -2。

[0019] Preferably, the dropping amount of ferric chloride is 30 μL / cm -2 。

[0020] In the present invention, the addition amount of ferric chloride needs to be strictly controlled. If the added amount of ferric chloride is insufficient, the synthesized material will not be able to fully exhibit its due performance. While adding too much ferric chloride will significantly increase the absorption rate of the laser, resulting in too high a dilution rate of the synthesis layer, thereby affecting the synthesis uniformity and the quality of the finally formed vacant iron oxide.

[0021] In the above preparation method of a ferric oxide with rich oxygen vacancies and silicon carbide composite material, the dispersion amount of melamine in step S3 is 1 - 3 mg / cm -2 。

[0022] In the present invention, the addition amount of melamine also needs to be strictly controlled. If the amount of melamine used is insufficient, it will not be able to effectively create an oxygen-deficient environment, thus hindering the formation of oxygen vacancies. On the contrary, if the amount of melamine used is too much, it will excessively absorb the laser energy, thereby affecting the conversion efficiency of the underlying ferric chloride to iron oxide.

[0023] In the above preparation method of a ferric oxide with rich oxygen vacancies and silicon carbide composite material, in step S4, the laser composite treatment is carried out using a laser marking machine. The laser area of the laser marking machine is a square with a side length of 0.5 - 5 cm 2 and the scanning speed is 800 - 1500 mm / s -1 , the laser focal length is 1 - 10 mm above the sample, and the power is 1.0 - 3.0 W. By precisely controlling the synthesis area of the laser, the present invention can meet the diverse area requirements of electrode materials in different environments. Using a higher scanning speed can significantly improve the synthesis efficiency, thus effectively shortening the synthesis time. In addition, reasonably adjusting the laser focal length can make the laser energy evenly distributed on the surface of the sample, avoiding energy concentration caused by excessive focusing and preventing damage to the material substrate. By regulating different powers, vacant iron oxide materials with different properties can also be synthesized, further expanding its application range.

[0024] In the above preparation method of a ferric oxide with rich oxygen vacancies and silicon carbide composite material, in step S4, it is washed with deionized water at 60 - 80 °C during the washing process.

[0025] The present invention also provides a supercapacitor, and the supercapacitor includes the above ferric oxide with rich oxygen vacancies and silicon carbide composite material.

[0026] In the above supercapacitor, the supercapacitor is assembled from a ferric oxide with rich oxygen vacancies and silicon carbide composite material and a nickel hydroxide positive electrode material.

[0027] Preferably, the iron oxide - silicon carbide composite material rich in oxygen vacancies is used as the negative electrode material, and nickel hydroxide is used as the positive electrode material.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The present invention uses ferric chloride precursor and silicon carbide nanowires to be mixed and dried, and then melamine is dispersed on the surface of the dried material. By using a simple and rapid one - step laser synthesis method, an iron oxide - silicon carbide composite material with oxygen vacancies is directly synthesized in the air. As a negative electrode material for supercapacitors, this synthesis method is simple and fast. The synthesis process of the material can be completed in only a few seconds, with high repeatability and strong industrial application prospects.

[0030] 2. The present invention makes the laser energy evenly distributed on the material surface during the synthesis process through an effective defocusing strategy, and the controllable laser power further adjusts the temperature on the material surface during the synthesis process. Without damaging the silicon carbide nanowire substrate, ferric chloride is converted into oxygen - vacancy iron oxide, and the entire synthesis process is stable and controllable.

[0031] 3. Melamine added during the synthesis process of the present invention decomposes under the action of rapid high temperature to generate ammonia and carbon dioxide, creating a locally oxygen - deficient environment, which promotes the formation of abundant oxygen vacancies in the crystal structure of iron oxide. At the same time, the release of gas introduces a porous morphology of the material, significantly increasing the specific surface area. The synthesized iron oxide - silicon carbide composite material with oxygen vacancies integrates excellent mechanical stability and electrochemical performance.

[0032] 4. Both precise structural characterization and electrochemical tests of the present invention show that the locally oxygen - deficient environment caused by melamine added during the synthesis process induces the generation of oxygen vacancies in iron oxide. At the same time, the electrochemical test results show that, thanks to the oxygen vacancies generated by adding melamine, the iron oxide synthesized after adding melamine has more excellent electrochemical performance than the iron oxide synthesized without adding melamine, and at the same time shows excellent cycle stability.

[0033] 5. The oxygen - vacancy iron oxide - silicon carbide composite material of the present invention is used as the negative electrode material of a supercapacitor and constructs an asymmetric supercapacitor with a nickel hydroxide positive electrode material. The obtained supercapacitor has extremely high energy density and excellent cycle stability, which is due to the fact that the oxygen - vacancy iron oxide - silicon carbide nanowire material can provide a large surface area to fully contact with the electrolyte, excellent electrical conductivity, and fast charge transfer ability, improving the problems of poor long - term cycle stability and low energy density of supercapacitors. Brief Description of the Drawings

[0034] Figure 1They are the low-magnification and high-magnification scanning electron microscope images of the oxygen vacancy iron oxide carbide nanowire electrode material prepared in Example 1.

[0035] Figure 2 They are the XRD spectra of Example 1 and Comparative Example 1.

[0036] Figure 3 They are the comparison of the electron paramagnetic resonance spectra of the iron oxide material with oxygen vacancies prepared in Example 1 and the iron oxide material prepared in Comparative Example 1.

[0037] Figure 4 They are the cyclic voltammograms of the oxygen vacancy iron oxide nanowire electrode materials prepared in Examples 1-4 at different scan rates.

[0038] Figure 5 They are the cyclic voltammograms of Example 5 and Example 6 at the same scan rate.

[0039] Figure 6 They are the cyclic voltammograms of Comparative Example 2 at different scan rates.

[0040] Figure 7 They are the cyclic voltammograms of Example 1 and Comparative Example 1 at different scan rates.

[0041] Figure 8 They are the galvanostatic charge-discharge curves of Example 1 and Comparative Example 1 at the same current density.

[0042] Figure 9 They are the impedance curves of Example 1 and Comparative Example 1.

[0043] Figure 10 They are the areal specific capacities calculated for Example 1 at different current densities from 5 mA cm -2 to 25 mA cm -2

[0044] Figure 11 They are the capacity retention rate tests of the oxygen vacancy iron oxide nanowire electrode material prepared in Example 1 at a current density of 10 mA cm -2

[0045] Figure 12 They are the cyclic voltammograms of the oxygen vacancy iron oxide nanowire negative electrode and nickel hydroxide positive electrode prepared in Example 1 at a scan rate of 20 mV s -1

[0046] Figure 13 They are the cyclic voltammograms of the supercapacitor assembled with the oxygen vacancy iron oxide nanowire negative electrode and nickel hydroxide positive electrode prepared in Example 1 at different scan numbers.

[0047] Figure 14 ​​​It is the constant current charge-discharge curves of the supercapacitor assembled with the oxygen vacancy iron oxide nanowire negative electrode prepared in Example 1 and the nickel hydroxide positive electrode at different scan rates.

[0048] Figure 15 It is the series connection of two supercapacitors assembled with the oxygen vacancy iron oxide nanowire negative electrode prepared in Example 1 and the nickel hydroxide positive electrode.

[0049] Figure 16 For the stability test curve of the supercapacitor at 15 mA cm -2 The test results after 14,000 tests. Detailed implementation manners

[0050] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present invention.

[0051] Example 1:

[0052] This example provides a preparation method for the negative electrode material of an oxygen vacancy iron oxide carbide silicon nanowire supercapacitor, which includes the following steps:

[0053] S1. Thoroughly and evenly mix 3.24 g of anhydrous ferric chloride with 20 ml of 99.7 wt% ethanol solution to obtain a 1 mol L -1 Ferric chloride ethanol solution;

[0054] S2. With a dosage of 30 μL cm -2 Uniformly drop the 1 mol L -1 Ferric chloride ethanol solution on the surface of the silicon carbide nanowires and dry it on a hot plate at 80 °C for 10 minutes;

[0055] S3. Uniformly disperse 2 mg cm -2 Melamine on the surface of the dried ferric chloride silicon carbide material;

[0056] S4. In the air, use a laser marking machine to perform compounding on the dried material exposed to laser irradiation. The laser area is a 1×1 cm square, the scanning speed is 1000 mm s -1 , the laser focal length is 5 mm above the sample, and the power is 2.5 W. Directly compound to obtain a silicon carbide nanowire composite material with oxygen vacancies of iron oxide, and then rinse the laser-treated material with deionized water.

[0057] Example 2:

[0058] This example provides a method for preparing a negative electrode material of an oxygen vacancy iron oxide - silicon carbide nanowire supercapacitor, which includes the following steps:

[0059] S1. Thoroughly and evenly mix 3.24 g of anhydrous ferric chloride with 20 ml of 99.7 wt% ethanol solution to obtain a 1 mol / L -1 ethanol solution of ferric chloride;

[0060] S2. With a dosage of 30 μL / cm -2 , evenly drop - coat the 1 mol / L -1 ethanol solution of ferric chloride on the surface of silicon carbide nanowires and dry it on a hot plate at 80 °C for 10 minutes;

[0061] S3. Evenly disperse 2 mg / cm -2 melamine on the surface of the dried ferric chloride - silicon carbide material;

[0062] S4. In air, use a laser marking machine to expose the dried material to laser irradiation for compounding. The laser area is a 1×1 cm square, the scanning speed is 1000 mm / s -1 , the laser focal length is 5 mm above the sample, and the power is 0.5 W. Directly obtain a composite material of iron oxide - silicon carbide nanowires with oxygen vacancies, and then rinse the laser - treated material with deionized water.

[0063] Example 3:

[0064] This example provides a method for preparing a negative electrode material of an oxygen vacancy iron oxide - silicon carbide nanowire supercapacitor, which includes the following steps:

[0065] S1. Thoroughly and evenly mix 3.24 g of anhydrous ferric chloride with 20 ml of 99.7 wt% ethanol solution to obtain a 1 mol / L -1 ethanol solution of ferric chloride;

[0066] S2. With a dosage of 30 μL / cm -2 , evenly drop - coat the 1 mol / L -1 ethanol solution of ferric chloride on the surface of silicon carbide nanowires and dry it on a hot plate at 80 °C for 10 minutes;

[0067] S3. Evenly disperse 2 mg / cm -2 melamine on the surface of the dried ferric chloride - silicon carbide material;

[0068] S4. In air, use a laser marking machine to expose the dried material to laser irradiation for compounding. The laser area is a 1×1 cm square, the scanning speed is 1000 mm / s -1, the laser focal length is 5 mm above the sample, and the power is 1.5 W. Directly compound to obtain iron oxide-silicon carbide nanowire composite with oxygen vacancies, and then rinse the laser-treated material with deionized water.

[0069] Example 4:

[0070] This example provides a method for preparing a negative electrode material of an oxygen vacancy iron oxide-silicon carbide nanowire supercapacitor, which includes the following steps:

[0071] S1. Thoroughly and evenly mix 3.24 g of anhydrous ferric chloride with 20 ml of 99.7 wt% ethanol solution to obtain 1 mol / L -1 ferric chloride ethanol solution;

[0072] S2. With a dosage of 30 μL / cm -2 uniformly dropwise coat the 1 mol / L -1 ferric chloride ethanol solution on the surface of silicon carbide nanowires and dry it on a hot plate at 80 °C for 10 minutes;

[0073] S3. Uniformly disperse 2 mg / cm -2 melamine on the surface of the dried ferric chloride-silicon carbide material;

[0074] S4. In the air, use a laser marking machine to expose the dried material to laser irradiation for compounding. The laser area is a 1×1 cm square, and the scanning speed is 1000 mm / s -1 , the laser focal length is 5 mm above the sample, and the power is 3.5 W. Directly compound to obtain iron oxide-silicon carbide nanowire composite with oxygen vacancies, and then rinse the laser-treated material with deionized water.

[0075] Example 5:

[0076] The difference from Example 1 is only that the addition amount of the 1 mol / L -1 ferric chloride ethanol solution in step S1 is 10 μL.

[0077] Example 6:

[0078] The difference from Example 1 is only that the addition amount of the 1 mol / L -1 ferric chloride ethanol solution in step S1 is 50 μL.

[0079] Comparative Example 1:

[0080] S1. Thoroughly and evenly mix 3.24 g of anhydrous ferric chloride with 20 ml of 99.7 wt% ethanol solution to obtain 1 mol / L -1 ferric chloride ethanol solution;

[0081] S2. With a dosage of 30 μL / cm-2 The dosage of -1 The ethanol solution of ferric chloride was evenly drop-coated on the surface of silicon carbide nanowires and dried on a hot plate at 80 °C for 10 minutes;

[0082] S3. In air, using a laser marking machine, the dried sample was exposed to laser irradiation for compounding. The laser area was a 1×1 cm square, and the scanning speed was 1000 mm / s -1 , the laser focal length was 5 mm above the sample, and the power was 2.5 W. The supercapacitor negative electrode material of iron oxide silicon carbide nanowires was directly obtained by compounding. Subsequently, the laser-treated material was rinsed with deionized water.

[0083] Comparative Example 2:

[0084] The difference from Example 1 was only that in step S3, 5 mg / cm -2 Melamine was evenly dispersed on the surface of the dried ferric chloride silicon carbide material.

[0085] Figure 1 are the low-magnification and high-magnification scanning electron microscope images of the oxygen vacancy iron oxide silicon carbide nanowire electrode material prepared in Example 1. It can be seen that Figure 1 oxygen vacancy iron oxide is evenly coated on the silicon carbide nanowires. At the same time, the surface of oxygen vacancy iron oxide has many irregular concave and convex shapes, which is more conducive to the full contact of the electrolyte.

[0086] Figure 2 are the XRD patterns prepared in Example 1 and Comparative Example 1. It can be seen from the figure that the diffraction peak positions of the prepared oxygen vacancy iron oxide and iron oxide are consistent with JCPDS#80-2377, indicating that the prepared iron oxide belongs to Fe2O3. The silicon carbide diffraction peak is consistent with the JCPDS#29-1129 card, indicating that the silicon carbide is 3C silicon carbide.

[0087] Figure 3 is the comparison of the electron paramagnetic resonance spectra of the iron oxide material with oxygen vacancies prepared in Example 1 and the iron oxide material prepared in Comparative Example 1. It can be seen that the iron oxide material with oxygen vacancies has a more obvious electron paramagnetic response, indicating that the iron oxide material with oxygen vacancies prepared in Example 1 has more oxygen vacancies.

[0088] Figure 4 are the cyclic voltammograms of the oxygen vacancy iron oxide nanowire electrode materials prepared in Examples 1-4 at different scan rates. It can be seen that the electrode material prepared at a combined power of 2.5 W has the best current response, representing the highest capacity.

[0089] Figure 5It can be seen from the cyclic voltammograms of Example 5 and Example 6 at the same scanning rate that, compared with the oxygen vacancy iron oxide material prepared in Example 1, the curve areas of Example 5 and Example 6 are both smaller than that of Example 1, indicating that adding too little or too much ferric chloride will affect the performance of the material, and at the same time, it also proves that the addition amount of ferric chloride in Example 1 is the optimal addition amount.

[0090] Figure 6 It can be seen from the cyclic voltammograms of Comparative Example 2 at different scanning rates compared with Example 1 that the area enclosed by the curve of Example 1 is larger than that of Comparative Example 3, indicating that Example 1 has a larger specific capacitance, which shows that excessive addition of melamine is not conducive to synthesis, and at the same time, it also proves that the addition amount of melamine in Example 1 is the optimal addition amount.

[0091] Figure 7 It can be seen from the cyclic voltammograms of Example 1 and Comparative Example 1 at the same scanning rate that the oxygen vacancy iron oxide material prepared in Example 1 has a larger closed area, representing a higher capacity.

[0092] Figure 8 It can be seen from the galvanostatic charge-discharge curves of Example 1 and Comparative Example 1 at the same current density that the oxygen vacancy iron oxide material prepared in Example 1 has a longer charge-discharge time, representing the ability to store a higher capacity.

[0093] Figure 9 It can be seen from the impedance curves of Example 1 and Comparative Example 1 that the oxygen vacancy iron oxide material prepared in Example 1 has a smaller intercept with the horizontal axis, representing a smaller charge transfer impedance and more excellent electrochemistry kinetics.

[0094] Figure 10 It is Example 1 at 5 mA cm -2 to 25 mA cm -2 The areal specific capacitances calculated at different current densities show that the material has excellent rate performance and outstanding areal specific capacitance.

[0095] Figure 11 It is the capacity retention rate test of the oxygen vacancy iron oxide nanowire electrode material prepared in Example 1 at a current density of 10 mA cm -2 After 10,000 cycles of galvanostatic charge-discharge, the material can still maintain 86.7% of the initial capacity, proving the excellent cycle stability of the material. At the same time, the galvanostatic charge-discharge curves in the inset also show an approximately isosceles triangle shape, proving the excellent and stable capacitive performance.

[0096] Figure 12 It is the oxygen vacancy iron oxide silicon carbide nanowire negative electrode prepared in Example 1 and the nickel hydroxide positive electrode at 20 mV s -1The cyclic voltammetry curves at a certain scan rate show that this matching strategy can further expand the working voltage window of the supercapacitor device. As can be seen from the figure, the working voltage of the supercapacitor device after matching design can reach 1.5 V, demonstrating good capacitance performance.

[0097] Figure 13 are the cyclic voltammetry curves of the supercapacitor assembled with the oxygen vacancy iron oxide nanowire negative electrode and nickel hydroxide positive electrode prepared in Example 1 at different scan rates. As can be seen from the figure, as the scan rate increases, the curve can still maintain the same shape, proving that the capacitor has good reversibility and electron transferability.

[0098] Figure 14 are the galvanostatic charge-discharge curves of the supercapacitor assembled with the oxygen vacancy iron oxide nanowire negative electrode and nickel hydroxide positive electrode prepared in Example 1 at different scan rates. As can be seen from the figure, the charge-discharge curve shows an approximately isosceles triangle standard capacitance curve, verifying its good capacitance behavior.

[0099] Figure 15 Two supercapacitors assembled with the oxygen vacancy iron oxide silicon carbide nanowire negative electrode and nickel hydroxide positive electrode prepared in Example 1 were connected in series, and successfully lit an LED electronic sign with a working voltage of 2.8 V, demonstrating strong practical application ability.

[0100] Figure 16 For the stability test curve of the supercapacitor assembled with the oxygen vacancy iron oxide silicon carbide nanowire negative electrode and nickel hydroxide positive electrode prepared in Example 1 at 15 mA cm -2 After 14,000 tests, it can still maintain 80.6% of the initial capacity, proving its excellent stability.

[0101] Table 1: Test results of the electrochemical performance of the oxygen vacancy iron oxide nanowire negative electrodes prepared in Examples 1-6 and Comparative Examples 1-3.

[0102]

[0103]

[0104] As can be seen from the above results, in Example 5, due to the initial addition amount of ferric chloride being much lower than the ideal value, the active components in the finally formed iron oxide silicon carbide material are insufficient, thus affecting the electrochemical performance. The measured areal specific capacitance is only 134.3 mF / cm 2, significantly lower than that of other Example 1; Example 6 performs better than Example 5, but still does not achieve the optimal effect, indicating that excessive ferric chloride will affect the effect of subsequent steps, such as laser composite treatment, etc., thus reducing the overall performance; Comparative Example 1, due to the lack of the help of melamine, cannot effectively create an anoxic environment, which is not conducive to the formation of oxygen vacancies and limits its application potential as a high-performance anode material; Although the performance data of Comparative Example 2 is close to that of Example 3, excessive melamine will cause excessive absorption of laser energy, affect the conversion efficiency of ferric chloride to iron oxide, and cause unnecessary side reactions or structural defects, which is not conducive to the stability and improvement of material performance in the long run.

[0105] The negative electrode material of the oxygen vacancy iron oxide silicon carbide nanowire supercapacitor of the present invention and the nickel hydroxide positive electrode material are used to construct an asymmetric supercapacitor. The obtained supercapacitor has extremely high energy density and excellent cycle stability, which is due to the fact that the oxygen vacancy iron oxide silicon carbide nanowire material can provide a large surface area to fully contact with the electrolyte, excellent electrical conductivity and fast charge transfer ability, improving the problems of poor long-term cycle stability and low energy density of the supercapacitor.

[0106] For the points not exhausted in the technical scope required to be protected by the present invention in the embodiments herein and the new technical solutions formed by the equivalent replacement of single or multiple technical features in the technical solutions of the embodiments, they are also within the scope required to be protected by the present invention; at the same time, in all the embodiments listed or not listed in the present invention, the various parameters in the same embodiment only represent an example of its technical solution (i.e., a feasible solution), and there is no strict cooperation and limitation relationship between the various parameters. Among them, the various parameters can be replaced with each other without violating the axiom and the requirements of the present invention, unless otherwise specifically stated.

[0107] The technical means disclosed in the technical solution of the present invention are not limited to the technical means disclosed in the above technical means, but also include the technical solutions composed of any combination of the above technical features. The above is the specific implementation manner of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and retouches can be made, and these improvements and retouches are also regarded as the protection scope of the present invention.

[0108] The specific embodiments described herein are only illustrative of the spirit of the present invention. Those skilled in the art of the present invention can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. An oxygen vacancy-rich iron oxide silicon carbide composite material, characterized in that: The composite material is prepared by laser compounding of ferric chloride, silicon carbide nanowires and melamine.

2. A method for preparing the oxygen vacancy-rich iron oxide silicon carbide composite material as claimed in claim 1, characterized in that: The method comprises the following steps: S1, fully and evenly mixing ferric chloride and an organic solvent to obtain a ferric chloride solution; S2, evenly drop-coating the ferric chloride solution on the surface of the silicon carbide nanowires, and then fully drying to obtain the ferric chloride-coated silicon carbide nanowire material; S3, evenly dispersing melamine on the surface of the dried ferric chloride-coated silicon carbide nanowire material; S4, then perform laser composite treatment, and finally wash to obtain the negative electrode material.

3. The method for preparing the oxygen vacancy-rich iron oxide silicon carbide composite material according to claim 2, characterized in that: The organic solvent is at least one of ethanol, propanol and ethylene glycol.

4. The method for preparing the oxygen vacancy-rich iron oxide silicon carbide composite material according to claim 2, characterized in that: The concentration of ferric chloride in step S1 ferric chloride solution is 0.5-3 mol / L -1 .

5. The method for preparing the oxygen vacancy-rich iron oxide silicon carbide composite material according to claim 2, characterized in that: Step S2: The amount of ferric chloride solution applied is 15-45 μL cm -2 .

6. The method for preparing the oxygen vacancy-rich iron oxide silicon carbide composite material according to claim 2, characterized in that: Step S3: the dispersion amount of melamine is 1-3 mg cm -2 .

7. The method for preparing the oxygen vacancy-rich iron oxide silicon carbide composite material according to claim 2, characterized in that: Step S4 laser compound processing is performed using a laser marking machine, and the laser area of ​​the laser marking machine is 0.5-5cm 2 The scanning speed is 800-1500mm s -1 , the laser focal length is 1-10mm above the sample, and the power is 1.0-3.0W.

8. The method for preparing the oxygen vacancy-rich iron oxide silicon carbide composite material according to claim 2, characterized in that: The washing process in step S4 is performed with deionized water at 60-80°C.

9. A supercapacitor, characterized in that: The supercapacitor comprises the oxygen vacancy-rich iron oxide silicon carbide composite material according to claim 1.

10. A supercapacitor according to claim 9, characterized in that: The supercapacitor is assembled from an oxygen vacancy-rich iron oxide silicon carbide composite material and nickel hydroxide.

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