A diacetylferrocene composite porous silicon electrode material and its preparation and application

Abstract

The present invention provides a diacetylferrocene composite porous silicon electrode material, and its preparation and application. The electrode material is obtained by solid-phase reaction of porous silicon and diacetylferrocene. In the present invention, an electrode material obtained by composite diacetylferrocene and porous silicon is used in a composite electrode. On the one hand, a π-electron conjugated system is formed, thereby improving the specific capacity of the porous silicon and the charge-discharge performance of the composite electrode. On the other hand, the hydrogen-oxygen bond on the acetyl group strengthens the binding force with the porous silicon, reducing the volume expansion of the porous silicon during charge and discharge, improving the charge-discharge capacity and safety of the composite electrode, and thus significantly improving the electrochemical performance of the composite electrode.

Description

Technical Field

[0001] The present invention belongs to the field of battery technology and more specifically relates to a diacetylferrocene composite porous silicon electrode material and its preparation and application. Background Art

[0002] In recent years, with the rapid development of science and technology, the demand for electronic products and electric vehicles has increased, and consumer demand for commercial batteries has become increasingly difficult to meet. Among them, lithium-ion batteries (LIBs), as one of the emerging energy sources, offer advantages over other batteries, such as high specific capacity, high output voltage, thorough charge and discharge, low self-discharge rate, and a wide operating temperature range. They have been widely used in various fields, including electronic devices. However, currently available LIBs still have inherent shortcomings: First, battery performance tends to deteriorate significantly at low temperatures (winter), resulting in a drop in discharge platform and reduced output power. Second, due to the highly active components of LIBs, prolonged use at high temperatures (summer) can lead to electrolyte decomposition, combustion, and even explosion. Third, overcharging or over-discharging can easily cause irreversible damage to the battery itself. Fourth, the battery's capacity is limited. Therefore, to meet the requirements of an ideal power source for electronic devices, LIBs and electrode materials must develop towards higher energy density, higher power density, greater safety, reliability, and environmental friendliness. The search for high-energy-density and high-capacity LIB cathode and cathode materials has become a research priority both domestically and internationally.

[0003] As a new porous semiconductor material, porous silicon has a large specific surface area, high surface chemical activity, a theoretical specific capacity of up to 4200mAh / g, and a moderate potential platform. It is one of the most promising negative electrode materials for second-generation lithium-ion batteries. The energy it emits is greater than that of single-crystalline silicon, indicating that compared with single-crystalline silicon, porous silicon can store more energy. In addition, porous silicon can significantly improve the comprehensive performance of electrode materials and is more suitable as an electrode material. For example, the prior art discloses a lithium-ion battery nanoporous silicon negative electrode material, but the porous silicon in the negative electrode material is prone to volume expansion during the charge and discharge process, and the preparation method is cumbersome and complicated, which is not conducive to mass promotion.

[0004] Therefore, it is quite necessary for the battery field to find an electrode material that can reduce the volume expansion of porous silicon during charging and discharging and is simple and convenient to prepare. Summary of the Invention

[0005] The present invention aims to address the deficiencies of the prior art and to provide a diacetylferrocene composite porous silicon electrode material, which is not only simple to prepare but also compounds diacetylferrocene with porous silicon to reduce the volume expansion of the porous silicon during charge and discharge, thereby improving the electrochemical performance of the composite electrode.

[0006] The first object of the present invention is to provide a method for preparing a diacetylferrocene composite porous silicon electrode material.

[0007] The second object of the present invention is to provide an electrode material prepared by the above method.

[0008] The third object of the present invention is to provide the use of the above electrode material in preparing a composite electrode.

[0009] A fourth object of the present invention is to provide a method for preparing a composite electrode.

[0010] The fifth object of the present invention is to provide a composite electrode prepared by the above method.

[0011] A sixth object of the present invention is to provide use of the above electrode material or composite electrode in preparing a battery.

[0012] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0013] The present invention provides a method for preparing a diacetylferrocene composite porous silicon electrode material. The preparation method comprises the following steps: obtaining the electrode material by solid-phase reaction of porous silicon and diacetylferrocene.

[0014] Ferrocene consists of two upper and lower planar rings and a divalent iron atom, surrounded by a stable structure of 18 electrons. This unique structure gives ferrocene unique properties in many aspects, such as good thermal stability, good chemical stability, good cyclic voltammetric charge-discharge performance, radiation resistance, charge-richness, redox properties, aromaticity, low toxicity, lipophilicity, etc., and can be used in combination with porous silicon to improve the electrochemical performance of the composite electrode. In order to further improve the electrochemical performance of the electrode when porous silicon is used as an electrode material, the present invention introduces a diacetyl group on the basis of ferrocene, that is, diacetylferrocene (CAS: 1273-94-5), one of the important derivatives of ferrocene, is added to the porous silicon for compounding, and the obtained electrode material is then prepared into a composite electrode. On the one hand, a π-electron conjugated system is formed, which improves the specific capacity of the porous silicon and the charge-discharge performance of the composite electrode. On the other hand, the hydrogen-oxygen bond on the acetyl group strengthens the binding force with the porous silicon, reduces the volume expansion of the porous silicon during charge and discharge, improves the charge-discharge capacity and safety of the composite electrode, and thus significantly improves the electrochemical performance of the composite electrode.

[0015] Preferably, the molar ratio of the porous silicon to diacetylferrocene is 1-2:1-2.

[0016] Most preferably, the molar ratio of the porous silicon to diacetylferrocene is 2:1.

[0017] Preferably, the porous silicon is prepared by reacting lithium aluminum hydride with silicon dioxide in a single step, wherein the reaction formula is LiAlH4 + SiO2 = LiAlO2 + Si + 2H2↑. Lithium aluminum hydride has a strong reducing property and is prone to explosion upon contact with water. Therefore, the reaction must be carried out in a dry environment, such as by covering the surface of the reactants with carbon powder to remove oxygen and prevent the reaction of oxygen with hydrogen to form water.

[0018] More preferably, lithium aluminum hydride and silicon dioxide are mixed and ground, heated to 80-110° C., held for 15-25 minutes, then heated to 540-560° C., held for 400 minutes, and then cooled to 20-30° C. The reaction system is then immersed in dilute hydrochloric acid, stirred for 10-14 hours, filtered, washed, and dried to obtain the porous silicon. Hydrofluoric acid may be added dropwise to the reaction system before immersion in dilute hydrochloric acid to remove unreacted silicon dioxide.

[0019] More preferably, lithium aluminum hydride and silicon dioxide are mixed and ground in a mass ratio of 0.6 to 1.0: 1.1 to 1.4, covered with carbon powder, heated to 80 to 110°C and controlled the heating time to be 13 to 17 minutes, kept warm for 15 to 25 minutes, then heated to 540 to 600°C and controlled the heating time to be 95 to 105 minutes, kept warm for 380 to 420 minutes, cooled to 20 to 30°C, and then the reaction system is immersed in dilute hydrochloric acid, stirred for 10 to 14 hours, vacuum filtered, washed, and kept warm at 90 to 110°C for 10 to 14 hours to obtain the porous silicon.

[0020] Preferably, the solid phase reaction is a grinding reaction.

[0021] More preferably, the grinding reaction is to mix diacetylferrocene and porous silicon and grind them for 0.8 to 1.3 hours, and most preferably, grind them for 1 hour.

[0022] The composite electrode prepared using the above electrode material forms a π-electron conjugated system, which improves the specific capacity of porous silicon and the charge-discharge performance of the composite electrode. On the other hand, the hydrogen-oxygen bond on the acetyl group strengthens the binding force with porous silicon, reducing the volume expansion of porous silicon during charge and discharge, improving the charge-discharge capacity and safety of the composite electrode, and thus significantly improving the electrochemical performance of the composite electrode. Therefore, the electrode material prepared by the above method and the application of the above electrode material in the preparation of the composite electrode should be within the scope of protection of the present invention.

[0023] In addition, the present invention also provides a method for preparing a composite electrode, wherein the composite electrode is obtained by coating the above electrode material on a nickel foam sheet.

[0024] Preferably, the preparation method is: mixing the above electrode materials, acetylene black and polytetrafluoroethylene, adding ethanol and mixing, concentrating, coating on a nickel foam sheet, drying, covering with a film and pressing to obtain the composite electrode.

[0025] More preferably, the mass ratio of the electrode material, acetylene black, and polytetrafluoroethylene is 15-17:2.5-3.5:1, and most preferably 16:3:1.

[0026] More preferably, the mass ratio of the ethanol to polytetrafluoroethylene is 3 to 5:1.

[0027] More preferably, the ethanol is anhydrous ethanol.

[0028] More preferably, the mixing is performed for 25 to 35 minutes, and most preferably for 30 minutes.

[0029] More preferably, the concentration is performed by heating at 75-85°C for 20-30 min, and most preferably, by heating at 80°C for 25 min.

[0030] Further preferably, the coating is single-sided coating.

[0031] More preferably, the drying is performed at 90-110° C. for 10-14 hours, and most preferably at 100° C. for 12 hours.

[0032] More preferably, the covering is to cover the coating surface with a film.

[0033] More preferably, the tableting is performed at 5-10 MPa for 4-6 seconds, and most preferably at 8 MPa for 5 seconds.

[0034] The composite electrode prepared by the above method forms a π-electron conjugated system, which improves the specific capacity of porous silicon and the charge-discharge performance of the composite electrode. On the other hand, the hydrogen-oxygen bond on the acetyl group strengthens the binding force with porous silicon, reducing the volume expansion of porous silicon during charge and discharge, improving the charge-discharge capacity and safety of the composite electrode, and thus significantly improving the electrochemical performance of the composite electrode. Therefore, the composite electrode prepared by the above method and the application of the above electrode material or composite electrode in the preparation of batteries should also be within the scope of protection of the invention.

[0035] Preferably, the battery is a lithium-ion battery.

[0036] The present invention has the following beneficial effects:

[0037] The present invention uses an electrode material obtained by combining diacetylferrocene and porous silicon in the composite electrode, which plays a synergistic role. On the one hand, a π-electron conjugated system is formed, which improves the specific capacity of the porous silicon and the charge and discharge performance of the composite electrode. On the other hand, the hydrogen-oxygen bond on the acetyl group is used to enhance the binding force with the porous silicon, which reduces the volume expansion of the porous silicon during charge and discharge, improves the charge and discharge capacity and safety of the composite electrode, and thus significantly improves the electrochemical performance of the composite electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a photo of the diacetylferrocene composite porous silicon electrode material obtained in Example 1.

[0039] Figure 2 These are photos of the diacetylferrocene composite porous silicon electrode materials obtained in Examples 1 to 3.

[0040] Figure 3 The following are photos of the tableting process of Example 4.

[0041] Figure 4 The particle size distribution diagram.

[0042] Figure 5 This is the SEM image of the diacetylferrocene composite porous silicon electrode material obtained in Example 1.

[0043] Figure 6 This is the SEM image of the diacetylferrocene composite porous silicon electrode material obtained in Example 2.

[0044] Figure 7 This is the SEM image of the diacetylferrocene composite porous silicon electrode material obtained in Example 3.

[0045] Figure 8 This is the XRD pattern of the diacetylferrocene composite porous silicon electrode material obtained in Example 1.

[0046] Figure 9 This is the XRD pattern of the diacetylferrocene composite porous silicon electrode material obtained in Example 2.

[0047] Figure 10 This is the XRD pattern of the diacetylferrocene composite porous silicon electrode material obtained in Example 3.

[0048] Figure 11 This is a photo of the electrode after immersion.

[0049] Figure 12 Schematic diagram of the connection between the reference electrode and the working electrode.

[0050] Figure 13 The electrochemical diagrams of the composite electrode obtained in Example 5 at different scan rates.

[0051] Figure 14 The electrochemical diagrams of the composite electrodes obtained in Examples 4 to 6 at a scan rate of 1 V / s are shown.

[0052] Figure 15 2 is the AC impedance diagram of the composite electrodes obtained in Examples 4 to 6.

[0053] Figure 16 for Figure 15 A partial enlarged view of . DETAILED DESCRIPTION

[0054] The present invention will be further described below with reference to the accompanying drawings and specific examples, but the examples do not limit the present invention in any way. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0055] Unless otherwise specified, all reagents and materials used in the following examples were commercially available.

[0056] 1. Experimental Reagents

[0057] The experimental reagents are shown in Table 1.

[0058] Table 1

[0059]

[0060] 2. Experimental Instruments

[0061] The experimental instruments are shown in Table 2.

[0062] Table 2

[0063]

[0064]

[0065] 3. Preparation of Porous Silicon

[0066] 0.8300 g of lithium aluminum hydride and 1.2000 g of white carbon black (active ingredient is silicon dioxide) were weighed separately using an electronic analytical balance, placed in an agate mortar, mixed and ground for 30 min, and then transferred to a zirconia crucible. 0.0200 g of carbon powder was evenly covered on the top of the mixture, and the zirconia crucible was placed in a muffle furnace for calcination (the calcination process was as follows: heating to 100°C and controlling the heating time for 15 min, holding the temperature for 20 min, then heating to 550°C and controlling the heating time for 100 min, holding the temperature for 4 After 100 minutes, the temperature was lowered to 25°C, and the calcined material was poured into a polytetrafluoroethylene beaker. Hydrofluoric acid was added dropwise to remove unreacted silica. The reaction system was then immersed in 4M dilute hydrochloric acid and stirred on a magnetic stirrer for 12 hours. After stirring, the reaction product was filtered using a circulating water vacuum pump and washed three times with distilled water. After being kept in a vacuum drying oven at 100°C for 12 hours, the reaction system was removed from the vacuum drying oven and ground in an agate mortar for 8 minutes to obtain the porous silicon. The preparation reaction formula of the porous silicon is LiAlH4+SiO2=LiAlO2+Si+2H2↑.

[0067] Example 1 Preparation of diacetylferrocene composite porous silicon electrode material

[0068] 1.12 g of porous silicon was taken, and the porous silicon and diacetylferrocene were mixed in a molar ratio of 2:1, and then ground in an agate mortar for 1 h to obtain the diacetylferrocene composite porous silicon electrode material (see photo). Figure 1 and Figure 2 As shown, it is a yellow-brown powder).

[0069] Example 2 Preparation of diacetylferrocene composite porous silicon electrode material

[0070] Same as Example 1, except that the mass of porous silicon is kept constant and the mass of diacetylferrocene is changed so that the molar ratio of porous silicon to diacetylferrocene is 1:1 (see photo). Figure 2 As shown, it is a yellow-brown powder).

[0071] Example 3 Preparation of diacetylferrocene composite porous silicon electrode material

[0072] Same as Example 1, except that the mass of porous silicon is kept constant and the mass of diacetylferrocene is changed so that the molar ratio of porous silicon to diacetylferrocene is 1:2 (see photo). Figure 2 As shown, it is a yellow-brown powder).

[0073] Example 4 Preparation of composite electrode

[0074] S1. Cut 1cm·1cm nickel foam sheets and nickel strips and weld them to make electrodes;

[0075] S2. The electrode material obtained in Example 1, acetylene black, and polytetrafluoroethylene were mixed in a mass ratio of 16:3:1, 4 mL of anhydrous ethanol was added, and the mixture was stirred in an ultrasonic cleaner for 30 min. The mixture was then heated in a digital constant temperature water bath at 80°C for 25 min until the mixture became viscous. The mixture was then coated on one side of a nickel foam sheet and dried in a precision programmable oven at 100°C for 12 h. The dried product was then taken out, and the side of the nickel foam sheet coated with the mixture was covered with a plastic film. The sheet was then pressed on a powder tablet press at a pressure of 8 MPa for 5 s (photos of the tableting process are shown in FIG. 1 ). Figure 3 As shown), the composite electrode is obtained.

[0076] Example 5 Preparation of composite electrode

[0077] The same as Example 1, except that the electrode material obtained in Example 1 is replaced by the electrode material obtained in Example 2.

[0078] Example 6 Preparation of composite electrode

[0079] The same as Example 1, except that the electrode material obtained in Example 1 is replaced by the electrode material obtained in Example 3.

[0080] Experimental Example 1 Particle Size Detection and Analysis of Diacetylferrocene Composite Porous Silicon Electrode Materials

[0081] 1. Test Method

[0082] The particle size of the diacetylferrocene composite porous silicon electrode material obtained in Example 2 was tested using a laser particle size distribution analyzer.

[0083] 2. Test Results

[0084] Particle size distribution diagram Figure 4 As shown, the horizontal axis is the particle size of the electrode material, the vertical axis corresponding to the red line is the particle content of the corresponding size, and the vertical axis corresponding to the blue line is the total content of particles less than or equal to the corresponding size.

[0085] It can be seen that the particle size distribution of the diacetylferrocene composite porous silicon electrode material is as high as 69% within the range of 4.468 to 41.94 μm, and the particle size is generally small and uniform, indicating that the electrode material has a large specific surface area and a high specific surface energy, and can store more charge, which is beneficial to improving the charge and discharge performance and specific capacity of the electrode, thereby significantly improving the electrochemical performance of the composite electrode.

[0086] Experimental Example 2 SEM Detection and Analysis of Diacetylferrocene Composite Porous Silicon Electrode Material

[0087] 1. Test Method

[0088] The diacetylferrocene composite porous silicon electrode materials obtained in Examples 1 to 3 were tested using a scanning electron microscope.

[0089] 2. Test Results

[0090] The SEM image of the diacetylferrocene composite porous silicon electrode material obtained in Example 1 is as follows: Figure 5 As shown, the SEM image of the diacetylferrocene composite porous silicon electrode material obtained in Example 2 is as follows: Figure 6 As shown, the SEM image of the diacetylferrocene composite porous silicon electrode material obtained in Example 3 is as follows Figure 7 shown.

[0091] Depend on Figure 5 It can be seen that when the SEM image is magnified 3000 times, the diacetylferrocene composite porous silicon electrode material obtained in Example 1 is mostly spherical, with many pore structures on the surface, and block crystals (ie, diacetylferrocene) are attached to the pore surface.

[0092] Depend on Figure 6 It can be seen that when the SEM image is magnified 3000 times, the surface of the diacetylferrocene composite porous silicon electrode material obtained in Example 2 has many pore structures, and block crystals (ie, diacetylferrocene) are attached to the pore surface.

[0093] Depend on Figure 7 It can be seen that when the SEM images are magnified 500 times and 1500 times, the surface of the diacetylferrocene composite porous silicon electrode material obtained in Example 3 has no obvious pore structure, and block crystals (i.e., diacetylferrocene) are attached to the surface. This is because the amount of diacetylferrocene used is significantly higher than that of porous silicon, causing the pores of the porous silicon to collapse.

[0094] In summary, the pore structure of the diacetylferrocene composite porous silicon electrode material obtained in Example 1 is the most obvious, indicating that the electrode material has a large specific surface area and a high specific surface energy, and can store more charge, which is beneficial to improving the charge and discharge performance and specific capacity of the electrode, thereby significantly improving the electrochemical performance of the composite electrode.

[0095] Experimental Example 3 XRD Detection and Analysis of Diacetylferrocene Composite Porous Silicon Electrode Material

[0096] 1. Test Method

[0097] The structures of the diacetylferrocene composite porous silicon electrode materials obtained in Examples 1 to 3 were characterized by X-ray diffractometer.

[0098] 2. Test Results

[0099] The XRD pattern of the diacetylferrocene composite porous silicon electrode material obtained in Example 1 is as follows: Figure 8As shown, the XRD pattern of the diacetylferrocene composite porous silicon electrode material obtained in Example 2 is as follows: Figure 9 As shown, the XRD pattern of the diacetylferrocene composite porous silicon electrode material obtained in Example 3 is as follows: Figure 10 shown.

[0100] Depend on Figures 8-10 It can be seen that the XRD patterns of the diacetylferrocene composite porous silicon electrode materials obtained in Examples 1 to 3 have sharp diffraction angles at 30.18° and 57.10°, which correspond to the crystal planes (220) and (511) of iron, respectively, and correspond to the standard values ​​of iron, indicating the presence of iron in the electrode material; in addition, there are sharp diffraction peaks at 23.7°, 28.4°, and 38.5° in the XRD patterns, which correspond to the crystal planes (210), (111), and (311) of silicon, respectively, and correspond to the standard values ​​of silicon, indicating the presence of silicon in the electrode material.

[0101] Experimental Example 4 Electrochemical Performance Test of Composite Electrode

[0102] 1. Test Method

[0103] The composite electrodes obtained in Examples 4 to 6 were placed in 6M KOH solution and soaked for 24 hours. The electrodes after soaking are shown in the following photos. Figure 11 As shown. Then take another 6M KOH solution and add it to the electrolytic cell. Figure 12 The reference electrode (calomel electrode) was connected to the composite electrodes obtained in Examples 4 to 6 respectively in a connection manner, and finally cyclic voltammetry and AC impedance performance tests were performed on an electrochemical workstation.

[0104] 2. Test Results

[0105] 1. Cyclic voltammetry test

[0106] (1) Cyclic voltammetry test results at different scan rates

[0107] Figure 13 The electrochemical diagrams of the composite electrode obtained in Example 5 at different scan rates (0.1 V / s, 0.3 V / s, 0.5 V / s, 0.8 V / s, and 1 V / s) are shown. It can be seen that at different scan rates in the cyclic voltammetry test, the positions of the redox peaks of the composite electrode change slightly, and as the scan rate increases, the reduction peak gradually shifts negatively—from 0.3 V at a scan rate of 0.1 V / s to 0.1 V at a scan rate of 1 V / s—while the oxidation peak gradually shifts positively—from 1.3 V at a scan rate of 0.1 V / s to 1.4 V at a scan rate of 1 V / s.

[0108] In addition, by Figure 13It can also be seen that as the scan rate increases, the current gradually increases, indicating that the electroactive substance is diffused into the cyclic voltammetry test solution during the increase in the scan rate. This is because the electrode materials of Examples 1 to 3 are coated when preparing the composite electrodes of Examples 4 to 6, and will not form a chemical bond with the nickel foam plate. Therefore, during the cycle test, the electroactive substance diacetylferrocene on the surface of the electrode material will partially diffuse into the cyclic voltammetry test solution, which is beneficial to increase the charge and discharge rate and current density of the battery, thereby significantly improving the electrochemical performance of the composite electrode.

[0109] (2) Cyclic voltammetry test results of different composite electrodes

[0110] Figure 14 The electrochemical diagrams of the composite electrodes obtained in Examples 4 to 6 at a scan rate of 1 V / s are shown. It can be seen that when the ratio of porous silicon to diacetylferrocene in the electrode material of the composite electrode is different, its oxidation peak and reduction peak are different. The curve between 0.7V and 1.1V is basically smooth and in an unreacted state; as the potential increases, the reaction begins; a reduction peak appears at 0.3V, and an oxidation peak appears at 1.4V. These two peaks are the potentials at which the redox reaction of the electrode material occurs. In addition, the oxidation peak current value of the diacetylferrocene composite porous silicon electrode material obtained in Example 1 is the largest, indicating the best electrochemical performance.

[0111] In addition, according to Figure 14 The discharge specific capacitance of the diacetylferrocene composite porous silicon electrode material obtained in Examples 1 to 3 can also be calculated based on the results when the voltage is -0.1 V to 1.5 V. The results are shown in Table 3. The calculation formula is: C = S / [2(v·s·m)], where S represents the integrated area, v represents the voltage, s represents the scan rate, and m represents the mass of the active substance.

[0112] Table 3

[0113] Integrated area (A·V) Mass of active substance (g) <![CDATA[Discharge specific capacitance (mA·h·g -1 )]]> Example 1 0.07636 0.00357 297.0744 Example 2 0.09900 0.00531 258.9454 Example 3 0.06074 0.00432 195.2803

[0114] It can be seen that the diacetylferrocene composite porous silicon electrode materials obtained in Examples 1 to 3 all have better discharge specific capacitance, and Example 1 is the best, having the best electrochemical performance. This is because diacetylferrocene effectively enhances the binding force with porous silicon through the hydrogen-oxygen bond on the acetyl group, reduces the volume expansion of porous silicon during charging and discharging, increases the charge and discharge capacity of the composite electrode, and thus significantly improves the electrochemical performance of the composite electrode.

[0115] 2. AC impedance test

[0116] Figure 15 The AC impedance diagram of the composite electrodes obtained in Examples 4 to 6 is shown in FIG. Figure 16 yes Figure 15A partial enlarged view of .

[0117] An AC frequency was applied between the composite electrodes obtained in Examples 4 to 6 and a reference electrode (calomel electrode). Figure 15 The left side of the middle curve is the high-frequency region, where the reference electrode and the composite electrode are mainly controlled by kinetics, and the main resistance comes from the electrolyte; the low-frequency region is the diffusion-controlled region between the composite electrode and the reference electrode. Figure 15 The right half of the middle curve shows a relatively gentle slope, indicating that the AC impedance of the composite electrodes obtained in Examples 4 to 6 is relatively small.

[0118] Among them, the semicircle of the high-frequency part of the AC impedance of the composite electrodes obtained in Examples 4 to 6 is the smallest, indicating that the impedance is the smallest, that is, the electrochemical performance is the best.

[0119] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing a diacetylferrocene composite porous silicon electrode material, characterized in that: Diacetylferrocene and porous silicon are mixed and ground for 0.8 to 1.3 hours to obtain the electrode material; wherein the molar ratio of the porous silicon to the diacetylferrocene is 1 to 2:1 to 2; the preparation method of the porous silicon is: lithium aluminum hydride and silicon dioxide are reacted in one step to obtain the porous silicon.

2. The electrode material prepared by the method according to claim 1.

3. Use of the electrode material according to claim 2 in the preparation of a composite electrode.

4. A method for preparing a composite electrode, characterized in that: The composite electrode is obtained by coating the electrode material according to claim 2 on a nickel foam sheet.

5. The method according to claim 4, characterized in that: The electrode material according to claim 2, acetylene black and polytetrafluoroethylene are mixed, ethanol is added and mixed, concentrated, coated on a nickel foam sheet, dried, covered with a film and then pressed to obtain the composite electrode.

6. The composite electrode prepared by the method according to claim 4 or 5.

7. Use of the electrode material according to claim 2 or the composite electrode according to claim 6 in preparing a battery.

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