A bamboo charcoal integrated electrode, its preparation method and application

Abstract

This invention discloses an integrated bamboo charcoal electrode, its preparation method, and its application, belonging to the field of battery technology. The preparation method of the integrated bamboo charcoal electrode includes the following steps: (1) soaking bamboo fiber cloth in a nickel-based catalyst solution, removing it, and drying it to obtain nickel-containing bamboo fiber cloth; (2) placing the nickel-containing bamboo fiber cloth between graphite clamps, pressing it, heat-treating it, and acid-washing it to obtain bamboo charcoal fiber cloth; (3) spraying a polytetrafluoroethylene solution onto one side of the bamboo charcoal fiber cloth and drying it to form a polytetrafluoroethylene coating; (4) using the bamboo charcoal fiber cloth as the working electrode, a graphite rod as the counter electrode, and a mixed solution of manganese sulfate and nickel sulfate as the electrolyte, electrodepositing a cobalt-doped nano-manganese dioxide catalyst layer on the other side of the bamboo charcoal fiber cloth to obtain the integrated bamboo charcoal electrode. The integrated bamboo charcoal electrode of this invention significantly improves the discharge performance and cycle stability of zinc-air batteries.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery, in particular to a bamboo charcoal integrated electrode and a preparation method and application thereof. BACKGROUND

[0002] Zinc-air batteries are attracting much attention due to their high theoretical energy density (about 1086 Wh / kg) and good safety, but their positive electrode materials usually rely on expensive carbon fibers (such as PAN-based) and platinum-based noble metal catalysts, resulting in high electrode costs. The cost of existing PAN-based carbon fiber electrode materials is as high as $50 / kg, and the noble metal catalyst further increases the cost burden. In addition, the traditional electrode has problems such as large interface impedance (usually higher than 5 Ω·cm) and insufficient three-phase reaction interface construction efficiency of less than 60%, which limits the kinetics of oxygen reduction reaction.

[0003] Although there have been attempts to replace it with biomass carbon materials (such as lignin, cellulose), but its poor electrical conductivity (resistivity > 10 Ω·cm), low mechanical strength (tensile strength < 1 MPa), it is difficult to meet the demand of zinc-air battery for high-efficiency ORR activity and structural stability.

[0004] In view of this, the present application is proposed. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art and provide a bamboo charcoal integrated electrode and a preparation method and application thereof. The bamboo charcoal integrated electrode of the present application can effectively improve the electrical conductivity and mechanical strength, and significantly improve the discharge performance and cycle stability of the zinc-air battery.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0007] A preparation method of a bamboo charcoal integrated electrode, comprising the following steps:

[0008] (1) Soak the bamboo fiber cloth in a nickel-based catalyst solution, take it out, dry it, and obtain a nickel-containing bamboo fiber cloth;

[0009] (2) Place the nickel-containing bamboo fiber cloth between the graphite clamps, press, heat treat, and acid wash to obtain a bamboo charcoal fiber cloth;

[0010] (3) Spray a polytetrafluoroethylene solution on one side of the bamboo charcoal fiber cloth, dry it, and form a polytetrafluoroethylene coating;

[0011] (4) Use the bamboo charcoal fiber cloth as the working electrode, the graphite rod as the counter electrode, and the mixed solution of manganese sulfate and nickel sulfate as the electrolyte, and electrodeposits a cobalt-doped nanometer manganese dioxide catalyst layer on the other side of the bamboo charcoal fiber cloth to obtain a bamboo charcoal integrated electrode.

[0012] As a preferred embodiment of the present application, the nickel-based catalyst solution is at least one of a 0.005-0.05 mol / L nickel acetate solution, a 0.005-0.05 mol / L NiBr2 solution, and a 0.005-0.05 mol / L nickel chloride solution.

[0013] As a preferred embodiment of the present application, the soaking temperature is 50-70℃, and the soaking time is 0.5-5h.

[0014] As a preferred embodiment of the present application, the pressing pressure is 1-25 MPa.

[0015] As a preferred embodiment of the present application, the heat treatment temperature is 700-1100℃, and the heat treatment time is 0.5-6h.

[0016] As a preferred embodiment of the present application, the heat treatment temperature is 900-1100℃, and the heat treatment time is 0.5-6h.

[0017] As a preferred embodiment of the present application, the concentration of polytetrafluoroethylene in the polytetrafluoroethylene solution is 10-30 wt%;

[0018] The thickness of the polytetrafluoroethylene coating is 10-30 μm.

[0019] As a preferred embodiment of the present application, the current density of the electrodeposition is 2-5 mA / cm 2 , and the electrodeposition time is 10-30 min.

[0020] As a preferred embodiment of the present application, the concentration of manganese sulfate in the electrolyte is 0.05-0.5 mol / L, and the concentration of cobalt sulfate in the electrolyte is 0.01-0.1 mol / L.

[0021] The present application also provides a bamboo-charcoal integrated electrode prepared by the above preparation method.

[0022] The present application also provides an application of the bamboo-charcoal integrated electrode in the preparation of a zinc-air battery, wherein the bamboo-charcoal integrated electrode is used as the positive electrode of the zinc-air battery.

[0023] The beneficial effects of the present application are that: (1) the present application can effectively improve the electrical conductivity and mechanical strength by the treatment of nickel-containing catalyst, graphite clamp pressing and synergistic induction graphitization technology, can significantly improve the tensile strength and reduce the resistivity compared with the non-induced (comparative example 2), by spraying polytetrafluoroethylene solution on one side of the bamboo charcoal fiber cloth, and electrodepositing a cobalt-doped nanometer manganese dioxide catalyst layer on the other side of the bamboo charcoal fiber cloth, a bamboo charcoal integrated electrode is obtained, which breaks through the limitation of traditional zinc-air battery positive electrode relying on pitch-based or polyacrylonitrile-based carbon fiber, has the advantages of low preparation cost, small interface resistance, high catalytic efficiency, etc., and significantly improves the discharge performance and cycle stability of the zinc-air battery.

[0024] (2) The method described in the present application is simple, has low requirements for raw materials, is suitable for various biomass fibers and synthetic fibers, and has good industrialization prospects. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is the pressing diagram of the nickel-containing bamboo fiber cloth and the graphite clamp.

[0026] Figure 2 It is the scanning electron microscope morphology diagram of the bamboo charcoal fiber prepared in Example 1 under different magnifications.

[0027] Figure 3 It is the scanning electron microscope morphology diagram of the Co-MnO2 / bamboo charcoal fiber prepared in Example 1 under different magnifications.

[0028] Figure 4 It is the scanning electron microscope EDS diagram of the Co-MnO2 / bamboo charcoal fiber prepared in Example 1. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0030] In the present application, the technical features described in an open manner include both the closed technical scheme consisting of the listed features and the open technical scheme containing the listed features.

[0031] In the present application, when a numerical range is referred to, unless otherwise specified, the numerical range is considered to be continuous and to include the minimum and maximum values of the range, as well as every value between the minimum and maximum values. Further, when a range is referred to as an integer, every integer between the minimum and maximum values of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood as including any and all sub-ranges subsumed therein.

[0032] In the present application, the specific dispersion and stirring method is not particularly limited.

[0033] The components and raw materials used in the embodiments and comparative examples of the present application are commercially available unless otherwise specified, and the components and raw materials used in each parallel experiment are the same.

[0034] The following examples are provided to facilitate an understanding of the present application. The provision of these examples is not intended to limit the scope of the claims.

[0035] Example 1

[0036] A method for preparing a bamboo charcoal integrated electrode includes the following steps:

[0037] (1) The bamboo fiber cloth is rinsed multiple times with deionized water and ethanol to remove surface contaminants, and then dried at 100°C to remove moisture;

[0038] The dried bamboo fiber cloth is cut into a 10 cm x 5 cm shape;

[0039] The bamboo fiber cloth is immersed in a nickel-based catalyst solution at 0.01 mol / L and 60°C for 2 hours, then removed and dried at 95°C to a constant weight to obtain a nickel-containing bamboo fiber cloth;

[0040] (2) As shown in Figure 1 , the nickel-containing bamboo fiber cloth (sample) is placed between graphite clamps (graphite flakes are placed between the graphite clamps and the nickel-containing bamboo fiber cloth), pressed at 10 MPa for 10 minutes, then placed in a high-temperature furnace, heated at 10°C / min from room temperature to 1100°C and held for 2 hours, naturally cooled to room temperature, and then treated with a 1 wt% hydrochloric acid solution to remove residual nickel catalyst to obtain a bamboo charcoal fiber cloth;

[0041] The mechanical property of the bamboo charcoal fiber was tested by using a universal material testing machine, and the test was carried out according to the standard GB / T 24218.18-2014, the tensile rate was 100 mm / s, the temperature was 20±2℃, and the humidity was 65±4%RH. The tensile strength of the sample of the embodiment was 15.75 MPa after the above method test. The resistivity of the sample of the embodiment was 2.36 Ω·cm by using a four-probe resistivity tester.

[0042] (3) Spraying 20wt% polytetrafluoroethylene solution on one side of the bamboo charcoal fiber cloth, drying to form a polytetrafluoroethylene coating with a thickness of 20μm;

[0043] (4) Using a mixed solution of 0.1mol / L MnSO4 and 0.05mol / L CoSO4 as an electrolyte, using the bamboo charcoal fiber cloth as a working electrode, using a graphite rod as a counter electrode, and using a current density of 3mA / cm² to electrodeposited a cobalt-doped nanometer manganese dioxide catalyst layer on the other side of the bamboo charcoal fiber cloth for 20min, to obtain a bamboo charcoal integrated electrode.

[0044] Figure 2 The bamboo charcoal fiber surface was shown to form an ordered graphite microcrystalline structure; Figure 3 The MnO2 nanoparticles were shown to be uniformly loaded; Figure 4 The EDS spectrum confirmed that the Co-Mn elements were uniformly distributed.

[0045] Example 2

[0046] A preparation method of a bamboo charcoal integrated electrode, comprising the following steps:

[0047] (1) The bamboo fiber cloth was rinsed multiple times with deionized water and ethanol to remove surface contaminants, and was dried at a temperature of 100℃;

[0048] The dried bamboo fiber cloth was cut into a shape of 10cm×5cm;

[0049] The bamboo fiber cloth was immersed in a nickel-based catalyst solution of 0.01 mol / L nickel chloride solution at 60℃ for 2h, and was taken out and dried at 95℃ to constant weight to obtain a nickel-containing bamboo fiber cloth;

[0050] (2) As shown in Figure 1 , the nickel-containing bamboo fiber cloth (sample) was placed between the graphite clamps (graphite microsheets were placed between the graphite clamps and the nickel-containing bamboo fiber cloth), and was pressed at 10MPa for 10min, and then was placed into a high-temperature furnace, and was heated at a rate of 10℃ / min from room temperature to 900℃ and was kept for 2h, and was naturally cooled to room temperature, and after removing the residual nickel catalyst with 1wt% hydrochloric acid solution, a bamboo charcoal fiber cloth was obtained;

[0051] The mechanical property of the bamboo charcoal fiber was tested by using a universal material testing machine, and the test was carried out in accordance with the standard GB / T 24218.18-2014, the tensile rate was 100 mm / s, the temperature was 20±2℃, and the humidity was 65±4%RH. The tensile strength of the sample of the embodiment was 12.75 MPa after the above method test. The resistivity test was carried out by using a four-probe resistivity tester, and the resistivity of the sample of the embodiment was 3.06 Ω·cm.

[0052] (3) Spraying 20wt% polytetrafluoroethylene solution on one side of the bamboo charcoal fiber cloth, drying to form a polytetrafluoroethylene coating with a thickness of 20μm;

[0053] (4) Using a mixed solution of 0.1mol / L MnSO4 and 0.05mol / L CoSO4 as an electrolyte, using the bamboo charcoal fiber cloth as a working electrode, using a graphite rod as a counter electrode, and using a current density of 3mA / cm² to electrodeposited a cobalt-doped nanoscale manganese dioxide catalyst layer on the other side of the bamboo charcoal fiber cloth for 20min, to obtain a bamboo charcoal integrated electrode.

[0054] Embodiment 3

[0055] Embodiment 3 is different from embodiment 1 in that step (2) is different, and the others are the same.

[0056] A preparation method of a bamboo charcoal integrated electrode, comprising the following steps:

[0057] (1) The bamboo fiber cloth was rinsed with deionized water and ethanol for multiple times to remove the surface pollutants, and then dried at a temperature of 100℃;

[0058] The dried bamboo fiber cloth was cut into a shape of 10cm×5cm;

[0059] The bamboo fiber cloth was immersed in a nickel-based catalyst solution of 0.01 mol / L nickel chloride solution at 60℃ for 2h, and then taken out and dried at 95℃ to constant weight to obtain a nickel-containing bamboo fiber cloth;

[0060] (2) As shown in Figure 1 , the nickel-containing bamboo fiber cloth (sample) was placed between the graphite clamps (graphite microparticles were placed between the graphite clamps and the nickel-containing bamboo fiber cloth), and then pressed at 10MPa for 10min, and then placed into a high-temperature furnace, and then heated from room temperature to 700℃ at a rate of 10℃ / min and kept for 2h, and then naturally cooled to room temperature, and then removed the residual nickel catalyst by using a 1wt% hydrochloric acid solution to obtain a bamboo charcoal fiber cloth;

[0061] The mechanical property of the bamboo charcoal fiber was tested by using a universal material testing machine, and the test was carried out in accordance with the standard GB / T 24218.18-2014, the tensile rate was 100 mm / s, the temperature was 20±2℃, and the humidity was 65±4%RH. The tensile strength of the sample of the embodiment was 8.60 MPa after the above method test. The resistivity test was carried out by using a four-probe resistivity tester, and the resistivity of the sample of the embodiment was 4.88 Ω·cm.

[0062] (3) Spraying 20wt% polytetrafluoroethylene solution on one side of the bamboo charcoal fiber cloth, drying to form a polytetrafluoroethylene coating with a thickness of 20μm;

[0063] (4) Using a mixed solution of 0.1mol / L MnSO4 and 0.05mol / L CoSO4 as an electrolyte, using the bamboo charcoal fiber cloth as a working electrode, using a graphite rod as a counter electrode, and using a current density of 3mA / cm² to electrodeposited a cobalt-doped nanoscale manganese dioxide catalyst layer on the other side of the bamboo charcoal fiber cloth for 20min, to obtain a bamboo charcoal integrated electrode.

[0064] Comparative Example 1

[0065] A preparation method of a bamboo charcoal integrated electrode, comprising the following steps:

[0066] (1) The bamboo fiber cloth was rinsed multiple times with deionized water and ethanol to remove surface contaminants, and then dried at a temperature of 100℃;

[0067] The dried bamboo fiber cloth was cut into a shape of 10cm×5cm;

[0068] The bamboo fiber cloth was immersed in a nickel-based catalyst solution of 0.01 mol / L nickel chloride solution at 60℃ for 2h, then taken out and dried at 95℃ to constant weight, to obtain a nickel-containing bamboo fiber cloth;

[0069] (2) As shown in Figure 1 , the nickel-containing bamboo fiber cloth (sample) was placed between the graphite clamps (graphite microparticles were placed between the graphite clamps and the nickel-containing bamboo fiber cloth), and then pressed at 10MPa for 10min, and then placed into a high-temperature furnace, and heated from room temperature to 1300℃ at a rate of 10℃ / min, and then naturally cooled to room temperature, and then removed the residual nickel catalyst by using a 1wt% hydrochloric acid solution, to obtain a bamboo charcoal fiber cloth;

[0070] The mechanical property of the bamboo charcoal fiber was tested by a universal material testing machine, and the test was performed in accordance with the GB / T 24218.18-2014 standard, the tensile rate was 100 mm / s, the temperature was 20±2℃, and the humidity was 65±4%RH. The tensile strength of the sample of the embodiment was 8.48 MPa after the above method test. The resistivity of the sample of the embodiment was 6.12 Ω·cm measured by a four-probe resistivity tester.

[0071] (3) Spraying 20wt% polytetrafluoroethylene solution on one side of the bamboo charcoal fiber cloth, drying to form a polytetrafluoroethylene coating with a thickness of 20μm;

[0072] (4) Using a mixed solution of 0.1mol / L MnSO4 and 0.05mol / L CoSO4 as an electrolyte, using the bamboo charcoal fiber cloth as a working electrode, using a graphite rod as a counter electrode, and using a current density of 3mA / cm² to electrodeposited a cobalt-doped nanoscale manganese dioxide catalyst layer on the other side of the bamboo charcoal fiber cloth for 20min, to obtain a bamboo charcoal integrated electrode.

[0073] Comparative Example 2

[0074] A method for preparing a bamboo charcoal integrated electrode, comprising the following steps:

[0075] (1) The bamboo fiber cloth was rinsed multiple times with deionized water and ethanol to remove surface contaminants, and then dried at a temperature of 100℃;

[0076] The dried bamboo fiber cloth was cut into a shape of 10cm×5cm;

[0077] The bamboo fiber cloth was immersed in a nickel-based catalyst solution of 0.01 mol / L nickel chloride solution at 60℃ for 2h, then taken out and dried at 95℃ to constant weight to obtain a nickel-containing bamboo fiber cloth;

[0078] (2) As shown in Figure 1 , the nickel-containing bamboo fiber cloth was placed in a high-temperature furnace, and the temperature was raised from room temperature to 1100℃ at a rate of 10℃ / min and kept for 2h, and then naturally cooled to room temperature to obtain a bamboo charcoal integrated electrode.

[0079] The mechanical property of the bamboo charcoal fiber was tested by a universal material testing machine, and the test was performed in accordance with the GB / T 24218.18-2014 standard, the tensile rate was 100 mm / s, the temperature was 20±2℃, and the humidity was 65±4%RH. The tensile strength of the sample of the embodiment was 8.48 MPa after the above method test. The resistivity of the sample of the embodiment was 6.12 Ω·cm measured by a four-probe resistivity tester.

[0080] The performance of the bamboo charcoal fiber induced by the graphite scheme of Comparative Example 1 and Example 1 is compared. Since the product of Comparative Example 2 has too poor mechanical performance to perform the subsequent electrodeposition step, there is no need to perform the electrical performance comparison.

[0081] Comparative Example 3

[0082] A preparation method of a bamboo charcoal integrated electrode includes the following steps:

[0083] (1) The bamboo fiber cloth is rinsed multiple times with deionized water and ethanol to remove surface contaminants, and is dried at a temperature of 100°C;

[0084] The dried bamboo fiber cloth is cut into a shape of 10 cm x 5 cm;

[0085] The bamboo fiber cloth is soaked in a nickel-based catalyst solution of 0.01 mol / L at 60°C for 2 h, taken out, and dried at 95°C to a constant weight to obtain a nickel-containing bamboo fiber cloth;

[0086] (2) As shown in Figure 1 , the nickel-containing bamboo fiber cloth (sample) is placed between graphite clamps (graphite microparticles are placed between the graphite clamps and the nickel-containing bamboo fiber cloth), pressed at 10 MPa for 10 min, and then placed into a high-temperature furnace, heated from room temperature to 1100°C at a rate of 10°C / min, and naturally cooled to room temperature. After removing the residual nickel catalyst with a 1 wt% hydrochloric acid solution, a bamboo charcoal fiber cloth is obtained;

[0087] The mechanical performance of the bamboo charcoal fiber is tested by a universal material testing machine, and the test is performed in accordance with the GB / T 24218.18-2014 standard, the tensile rate is 100 mm / s, the temperature is 20±2°C, and the humidity is 65±4%RH. The tensile strength of the sample of the present embodiment is 15.75 MPa after being tested by the above method. The resistivity of the sample of the present embodiment is 2.36 Ω·cm, which is tested by a four-probe resistivity tester.

[0088] (3) A 20 wt% polytetrafluoroethylene solution is sprayed on one side of the bamboo charcoal fiber cloth, dried, and a polytetrafluoroethylene coating layer with a thickness of 20 μm is formed;

[0089] (4) 0.1 mol / L MnSO4 is used as an electrolyte, the bamboo charcoal fiber cloth is used as a working electrode, a graphite rod is used as a counter electrode, and a current density of 3 mA / cm² is used to electrodeposition for 20 min on the other side of the bamboo charcoal fiber cloth to obtain a pure nano manganese dioxide / bamboo charcoal integrated electrode without cobalt doping.

[0090] Comparative Example 4

[0091] A preparation method of a bamboo charcoal integrated electrode includes the following steps:

[0092] (1) Rinse the bamboo fiber cloth multiple times with deionized water and ethanol to remove surface contaminants, and dry it at 100°C.

[0093] Cut the dried bamboo fiber cloth into 10cm×5cm shapes;

[0094] Bamboo fiber cloth was soaked in a nickel-based catalyst solution in a 0.01 mol / L nickel chloride solution at 60℃ for 2 hours, then removed and dried at 95℃ to constant weight to obtain nickel-containing bamboo fiber cloth.

[0095] (2) For example Figure 1 As shown, the nickel-containing bamboo fiber cloth (sample) was placed between graphite clamps (graphite micro-sheets were placed between the graphite clamps and the nickel-containing bamboo fiber cloth), pressed at 10 MPa for 10 min, and then placed in a high-temperature furnace. The temperature was increased from room temperature to 1100℃ at 10℃ / min and held for 2 h. After naturally cooling to room temperature, the residual nickel catalyst was removed with 1wt% hydrochloric acid solution to obtain bamboo charcoal fiber cloth.

[0096] The mechanical properties of bamboo charcoal fiber were tested using a universal testing machine, according to GB / T 24218.18-2014 standard. The tensile rate was 100 mm / s, the temperature was 20±2℃, and the humidity was 65±4%RH. The tensile strength of the sample in this embodiment was 15.75 MPa, as determined by the above method. The resistivity of the sample in this embodiment was measured to be 2.36 Ω‧cm using a four-probe resistivity meter.

[0097] (3) Spray 20wt% polytetrafluoroethylene solution onto one side of the bamboo charcoal fiber cloth, dry it, and form a polytetrafluoroethylene coating with a thickness of 20μm.

[0098] (4) Using a mixed solution of 0.05 mol / L CoSO4 as the electrolyte, bamboo charcoal fiber cloth as the working electrode, and graphite rod as the counter electrode, electrodeposit at a current density of 3 mA / cm² for 20 min, and electrodeposit a cobalt hydroxide catalyst layer on the other side of the bamboo charcoal fiber cloth. After further heat treatment, a cobalt tetroxide / bamboo charcoal integrated electrode is obtained.

[0099] Comparative Example 5

[0100] A method for preparing an integrated bamboo charcoal electrode includes the following steps:

[0101] (1) Rinse the bamboo fiber cloth multiple times with deionized water and ethanol to remove surface contaminants, and dry it at 100°C.

[0102] Cut the dried bamboo fiber cloth into 10cm×5cm shapes;

[0103] Bamboo fiber cloth was soaked in a nickel-based catalyst solution in a 0.01 mol / L nickel chloride solution at 60℃ for 2 hours, then removed and dried at 95℃ to constant weight to obtain nickel-containing bamboo fiber cloth.

[0104] (2) For example Figure 1 As shown, the nickel-containing bamboo fiber cloth (sample) was placed between graphite clamps (graphite micro-sheets were placed between the graphite clamps and the nickel-containing bamboo fiber cloth), pressed at 10 MPa for 10 min, and then placed in a high-temperature furnace. The temperature was increased from room temperature to 1100℃ at 10℃ / min and held for 2 h. After naturally cooling to room temperature, the residual nickel catalyst was removed with 1wt% hydrochloric acid solution to obtain bamboo charcoal fiber cloth.

[0105] The mechanical properties of bamboo charcoal fiber were tested using a universal testing machine, according to GB / T 24218.18-2014 standard. The tensile rate was 100 mm / s, the temperature was 20±2℃, and the humidity was 65±4%RH. The tensile strength of the sample in this embodiment was 15.75 MPa, as determined by the above method. The resistivity of the sample in this embodiment was measured to be 2.36 Ω‧cm using a four-probe resistivity meter.

[0106] (3) Using a mixed solution of 0.1 mol / L MnSO4 and 0.05 mol / L CoSO4 as the electrolyte, bamboo charcoal fiber cloth as the working electrode, and graphite rod as the counter electrode, a cobalt-doped nano-manganese dioxide catalyst layer was electrodeposited on one side of the bamboo charcoal fiber cloth for 20 min at a current density of 3 mA / cm² to obtain an integrated bamboo charcoal electrode.

[0107] Comparative Example 6

[0108] A method for preparing an integrated bamboo charcoal electrode includes the following steps:

[0109] (1) Rinse the bamboo fiber cloth multiple times with deionized water and ethanol to remove surface contaminants, and dry it at 100°C.

[0110] Cut the dried bamboo fiber cloth into 10cm×5cm shapes;

[0111] (2) For example Figure 1 As shown, the bamboo fiber cloth (sample) was placed between graphite fixtures (graphite micro-sheets were placed between the graphite fixtures and the nickel-containing bamboo fiber cloth), pressed at 10 MPa for 10 min, and then placed in a high-temperature furnace. The temperature was increased from room temperature to 1100℃ at 10℃ / min and held for 2 h, and then naturally cooled to room temperature.

[0112] The mechanical properties of bamboo charcoal fiber were tested using a universal testing machine, according to GB / T 24218.18-2014 standard. The tensile rate was 100 mm / s, the temperature was 20±2℃, and the humidity was 65±4%RH. The tensile strength of the sample in this embodiment was 5.25 MPa, as determined by the above method. The resistivity of the sample in this embodiment was measured to be 10.36 Ω‧cm using a four-probe resistivity meter.

[0113] (3) Spray 20wt% polytetrafluoroethylene solution onto one side of the bamboo charcoal fiber cloth, dry it, and form a polytetrafluoroethylene coating with a thickness of 20μm.

[0114] (4) Using a mixed solution of 0.1 mol / L MnSO4 and 0.05 mol / L CoSO4 as the electrolyte, bamboo charcoal fiber cloth as the working electrode and graphite rod as the counter electrode, a cobalt-doped nano-manganese dioxide catalyst layer was electrodeposited on the other side of the bamboo charcoal fiber cloth for 20 min at a current density of 3 mA / cm² to obtain an integrated bamboo charcoal electrode.

[0115] Test case

[0116] A zinc-air battery was assembled using a mixed solution of 6.0 mol / L KOH and 0.2 mol / L zinc acetate as the electrolyte. The open-circuit voltage, peak power density, and capacity retention after 100 cycles are shown in Table 1.

[0117] Table 1

[0118]

[0119] As can be seen from Table 1, the present invention, through nickel-containing catalyst treatment and graphite clamp pressing synergistic graphitization technology, can effectively improve conductivity and mechanical strength. Compared with the uninduced (Comparative Example 2), it can significantly improve tensile strength and reduce resistivity. By spraying polytetrafluoroethylene solution on one side of bamboo charcoal fiber cloth and electrodepositing a cobalt-doped nano-manganese dioxide catalyst layer on the other side of bamboo charcoal fiber cloth, an integrated bamboo charcoal electrode is obtained. This electrode breaks through the limitation of traditional zinc-air battery cathodes relying on pitch-based or polyacrylonitrile-based carbon fibers, and has the advantages of low preparation cost, low interfacial internal resistance, and high catalytic efficiency, significantly improving the discharge performance and cycle stability of zinc-air batteries.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a bamboo charcoal integrated electrode, characterized by, The method comprises the following steps: (1) soaking the bamboo fiber cloth in a nickel-based catalyst solution, taking out, drying to obtain a nickel-containing bamboo fiber cloth; (2) placing the nickel-containing bamboo fiber cloth between graphite clamps, pressing, heat treating, and pickling to obtain a bamboo charcoal fiber cloth; (3) spraying a polytetrafluoroethylene solution on one side of the bamboo charcoal fiber cloth, drying to form a polytetrafluoroethylene coating; (4) taking the bamboo charcoal fiber cloth as a working electrode, a graphite rod as a counter electrode, and a mixed solution of manganese sulfate and cobalt sulfate as an electrolyte, and electrodepositing a cobalt-doped nanometer manganese dioxide catalyst layer on the other side of the bamboo charcoal fiber cloth to obtain a bamboo charcoal integrated electrode. The heat treatment temperature is 700-1100℃.

2. The method for preparing the integrated bamboo charcoal electrode according to claim 1, characterized in that, The nickel-based catalyst solution is at least one of a 0.005-0.05 mol / L nickel acetate solution, a 0.005-0.05 mol / L NiBr2 solution, and a 0.005-0.05 mol / L nickel chloride solution.

3. The method for preparing the integrated bamboo charcoal electrode according to claim 1, characterized in that, The soaking temperature is 50-70℃, and the soaking time is 0.5-5h.

4. The method for preparing the integrated bamboo charcoal electrode according to claim 1, characterized in that, The pressing pressure is 1-25 MPa.

5. The method for preparing the integrated bamboo charcoal electrode according to claim 1, characterized in that, The heat treatment time is 0.5-6h.

6. The method for preparing the integrated bamboo charcoal electrode according to claim 1, characterized in that, The concentration of polytetrafluoroethylene in the polytetrafluoroethylene solution is 10-30wt%; The thickness of the polytetrafluoroethylene coating is 10-30μm.

7. The method for preparing the integrated bamboo charcoal electrode according to claim 1, characterized in that, The current density of the electrodeposition is 2-5 mA / cm 2 , and the electrodeposition time is 10-30 min.

8. The method for preparing the integrated bamboo charcoal electrode according to claim 1, characterized in that, The concentration of manganese sulfate in the electrolyte is 0.05-0.5mol / L, and the concentration of cobalt sulfate in the electrolyte is 0.01-0.1mol / L.

9. A bamboo charcoal integrated electrode, characterized by, The bamboo charcoal integrated electrode is prepared by the preparation method of any one of claims 1-8.

10. The use of the bamboo charcoal integrated electrode of claim 9 in the preparation of a zinc-air battery, characterized in that, The bamboo charcoal integrated electrode is used as a positive electrode of a zinc-air battery.

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