Preparation method of cold spraying in-situ compaction graphene / AlSi10Mg air electrode

Abstract

The invention provides a graphene / AlSi10Mg air battery based on in-situ auxiliary cold spraying additive manufacturing and a preparation method of the graphene / AlSi10Mg air battery. AlSi10Mg alloy powder is used as a matrix, the surface of the AlSi10Mg alloy powder is uniformly coated with graphene through a chemical reduction method, and an alloy block is prepared in combination with a cold spraying deposition technology and used for an air electrode anode. In the preparation process, stainless steel shots are added to achieve in-situ compaction, and the compactness of the alloy is remarkably improved. The graphene forms a three-dimensional conductive network which is used as a conductive medium to fill a passive film insulation gap, and the anode activity is enhanced by promoting an aluminum corrosion reaction, so that the reduction of the battery rate is inhibited. In-situ tamping is achieved, alloy structure micro-nano and matrix strengthening are achieved at the same time, and electrode mechanical and electrochemical performance is optimized. The anode shows excellent anode polarization characteristics and stable multiplying power in battery operation, and the problem of activity attenuation caused by passive film shielding of a traditional aluminum alloy electrode is effectively solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrode materials, and particularly relates to a preparation method of a cold spraying in-situ tamping graphene / AlSi10Mg air electrode. BACKGROUND

[0002] Metal-air batteries, as a new energy storage technology, are attracting more and more attention due to their high energy density, large capacity, and low-cost manufacturing (especially for aluminum metal). This type of battery has strong adaptability to working environment, is independent of load and temperature, and has the advantages of short charging period (through mechanical replacement of anode), environmental friendliness, no noise pollution, and low infrared radiation. They can provide sustainable and environmentally friendly power for electric vehicles, ship equipment, communication base stations, unmanned aerial vehicles, military equipment, and can also be used as backup power, emergency power, and mobile power.

[0003] The theoretical energy density of aluminum-air battery is about 8.1 kWh·kg -1 , second only to lithium-air battery (11.8 kWh·kg g -1 ), and higher than other metal-air batteries. Its actual energy density can currently reach 1.2 kWh·kg -1 , which provides a possible choice for replacing traditional gasoline engines. Metal Al as an air battery anode material has significant advantages, such as abundant reserves, low price, non-toxicity, safety, and a large aluminum industry production chain worldwide, so metal Al as an anode material for metal-air batteries is easier to achieve global promotion and application. However, the aluminum anode is prone to form a dense oxide film during use, resulting in positive shift of electrode potential and polarization reaction, which in turn leads to discharge voltage hysteresis; aluminum will undergo self-corrosion behavior in aqueous electrolyte, reducing the discharge efficiency of the aluminum anode. In order to improve these problems, people improve the discharge activity and efficiency of the aluminum anode through alloying, electrolyte optimization, and other methods. At the same time, improving the battery air permeability, electrolyte circulation structure, and electrode structure can also optimize the battery performance.

[0004] Aiming at the problems existing in cold spraying forming AlSi10Mg alloy, such as large coating porosity and active and passivation problems, surface protection technology can be used to prepare high-voltage corrosion-resistant coating to improve the stability of the anode under high voltage. This protective layer has the characteristics of simple and convenient preparation, low cost, high pressure resistance and long effect in design. By introducing graphene on the electrode interface, the electronegativity of graphene can improve the electrode polarization efficiency and ensure the discharge stability, which meets the harsh demands in industrial applications. In addition, the corrosion resistance of the combination of smelting and strengthening is also an important research direction to improve the performance of metal air battery. Although the new cold spraying coating has the disadvantages of short aging period, poor structure stability and poor corrosion resistance, but through continuous research and improvement, it is expected to realize more efficient and stable metal air battery technology. SUMMARY

[0005] The present application aims to at least solve one of the above technical problems existing in the prior art. To this end, the present application provides a preparation method, and the air electrode prepared by the method has excellent corrosion resistance and high electrochemical activity to meet the needs of high-performance metal air batteries.

[0006] The present application also provides a preparation method of an electrode material.

[0007] The present application also provides a cold spraying additive manufacturing technology.

[0008] The present application also provides a battery anode.

[0009] The present application also provides an aluminum air battery.

[0010] The first aspect of the present application provides a surface pretreatment technology for an aluminum alloy substrate, including sandblasting treatment and surface cleaning, the sandblasting treatment removes dust and oxide film and other impurities on the surface of the aluminum alloy, and the surface cleaning removes residual impurities.

[0011] One of the technical solutions of the surface pretreatment technology for the aluminum alloy substrate has at least the following beneficial effects: The cleanliness of the aluminum alloy substrate is improved, providing a basis for the uniform dispersion of Al2O3 nanoparticles and the effective coating of graphene oxide. The bonding force between the Al2O3 nanoparticles and the aluminum alloy substrate is enhanced, improving the structural stability of the composite material. By increasing the surface roughness of the substrate, the adhesion performance of the composite material and the substrate is optimized, which is beneficial to improve the application effect and service life of the composite material.

[0012] According to some embodiments of the present application, the carrier surface pretreatment includes sandblasting treatment and surface cleaning.

[0013] Sandblasting and surface cleaning is an effective surface modification technique. Adding this step in the preparation of composite materials can significantly improve the adhesion and stability of the coating, allowing the subsequent coating to adhere more firmly to the carrier surface. In addition, when preparing composite materials such as lithium batteries, fuel cells, etc., the cleanliness and roughness of the carrier surface are key factors affecting the performance of the coating. Sandblasting and surface cleaning as a step in the pretreatment of the carrier surface can serve as an improved coating-adhesion carrier, increase the surface roughness, and improve the bonding efficiency of the coating to the carrier, thereby increasing the overall performance of the composite material. Furthermore, in batteries and other electrochemical devices, carrier surface pretreatment is used to ensure uniform distribution of the coating and to transfer the required physical and chemical properties. Sandblasting and surface cleaning can help achieve uniform distribution of the coating, avoiding uneven accumulation of the coating in local areas, and reducing performance degradation and potential safety risks caused by uneven coating. Finally, especially when the composite material is subjected to long-term use and environmental influences, the carrier surface may be subjected to various stresses. The addition of sandblasting and surface cleaning can also increase the mechanical strength and chemical stability of the carrier, which is crucial for the long-term stable operation of the composite material.

[0014] The second aspect of the present application provides a graphene-coated AlSi10Mg composite powder.

[0015] One of the technical solutions of the present application relates to a graphene-coated AlSi10Mg composite powder, which has at least the following beneficial effects: The graphene-coated AlSi10Mg composite powder of the present application uses graphene oxide to coat AlSi10Mg alloy powder. Graphene oxide has good stability and barrier properties. Under its coating effect, the AlSi10Mg composite powder may have better oxidation resistance, corrosion resistance, and other properties in subsequent applications, thereby improving its use effect and service life.

[0016] According to some embodiments of the present application, the raw materials used to prepare the composite powder include: (1) 50 - 200 ml of GO dispersion liquid with a concentration of 0.1 - 0.3 mg / ml; (2) 10 - 20 g of AlSi10Mg alloy powder with a particle size of 30 - 50 μm.

[0017] According to some embodiments of the present application, the preparation method of the graphene-coated AlSi10Mg composite powder is: Put 50 - 200 ml of GO dispersion liquid with a concentration of 0.1 - 0.3 mg / ml in a suitable container, disperse the graphene oxide well in deionized water by ultrasonic, and stir for 30 - 90 min. Then, add 10 - 20 g of AlSi10Mg alloy powder with a particle size of 30 - 50 μm to the above GO dispersion liquid, continue to stir for 20 - 30 min until the solution becomes transparent. Finally, after washing and vacuum drying, the rGO / AlSi10Mg powder can be obtained.

[0018] The graphene-coated AlSi10Mg composite powder can be prepared by the above process, which may exhibit good performance in related applications.

[0019] The third aspect of the present application provides a preparation method of rGO / AlSi10Mg / Al2O3 / 316 mixed powder, comprising the following steps: mechanically mixing weighed rGO / AlSi10Mg powder, aluminum oxide powder (Al2O3) and 316 stainless steel particles to obtain the rGO / AlSi10Mg / Al2O3 / 316 mixed powder.

[0020] One of the technical solutions of the rGO / AlSi10Mg / Al2O3 / 316 mixed powder preparation method of the present application has at least the following beneficial effects: The preparation method of the present application is simple to operate, does not require complex processes and expensive equipment, and the raw materials are easy to obtain, so that the mixed powder with specific performance can be conveniently prepared and is suitable for industrial production.

[0021] In the mixed powder, the rGO / AlSi10Mg powder provides certain basic performance, the aluminum oxide powder (Al2O3) as a hard phase can improve the hardness and wear resistance of the mixed powder, and the 316 stainless steel particles can endow the mixed powder with good strength and corrosion resistance, and the three work together to make the mixed powder have more excellent comprehensive performance.

[0022] According to some embodiments of the present application, the weighed amount of the rGO / AlSi10Mg powder is 80 - 100 g.

[0023] According to some embodiments of the present application, the related parameters of the aluminum oxide powder (Al2O3) are as follows: The average particle size of the aluminum oxide powder (Al2O3) is 30 - 50 μm.

[0024] The weighed amount of the aluminum oxide powder (Al2O3) is 10 - 15 g.

[0025] According to some embodiments of the present application, the relevant parameters of the 316 stainless steel particles are as follows: The average particle size of the 316 stainless steel particles is 30-60 μm. The weighing amount of the 316 stainless steel particles is 30-60 g.

[0026] According to some embodiments of the present application, the preparation method of the rGO / AlSi10Mg / Al2O3 / 316 mixed powder is specifically as follows: 80-100 g of rGO / AlSi10Mg powder is weighed, 10-15 g of aluminum oxide powder (Al2O3) with an average particle size of 30-50 μm is added as a hard phase, and 30-60 g of 316 stainless steel particles with an average particle size of 30-60 μm is weighed, and the rGO / AlSi10Mg powder, the aluminum oxide powder (Al2O3), and the 316 stainless steel particles are mechanically mixed to obtain the rGO / AlSi10Mg / Al2O3 / 316 mixed powder.

[0027] The fourth aspect of the present application provides an SP-rGO / AlSi10Mg coating formed by spraying a specific mixed powder on an aluminum alloy substrate by a cold spraying technology.

[0028] One of the technical solutions of the SP-rGO / AlSi10Mg coating provided by the present application has at least the following beneficial effects: The SP-rGO / AlSi10Mg coating of the present application uses rGO / AlSi10Mg / Al2O3 / 316 mixed powder as raw material, rGO (reduced graphene oxide) has good flexibility and electrical conductivity, AlSi10Mg alloy has good mechanical properties, Al2O3 as a hard phase can improve the hardness of the coating, and 316 stainless steel particles can enhance the corrosion resistance of the coating. By combining these components on the aluminum alloy substrate through the cold spraying technology, the coating formed may have excellent comprehensive performance, such as good wear resistance, corrosion resistance, and mechanical properties, and can exhibit a long service life and stable performance in related applications.

[0029] According to some embodiments of the present application, the raw material used to prepare the coating is a rGO / AlSi10Mg / Al2O3 / 316 mixed powder, which is prepared by a specific process.

[0030] According to some embodiments of the present application, the substrate of the coating is an aluminum alloy substrate.

[0031] According to some embodiments of the present application, the preparation method of the SP-rGO / AlSi10Mg coating is a cold spraying technology, and the specific process parameters are as follows: The compressed air temperature used in the spraying process is 200-600°C; The pressure used in the spraying process is 0.6-1.5 MPa; The spraying gun moving speed is 50-200 mm / s; The powder supply speed provided by the powder supply bucket is 0.1-0.5 g / s.

[0032] The specific operation process is: the obtained rGO / AlSi10Mg / Al2O3 / 316 mixed powder is sprayed on an aluminum alloy substrate by cold spraying technology according to the above process parameters, and the coating obtained after cold spraying is marked as SP-rGO / AlSi10Mg. The SP-rGO / AlSi10Mg coating can be prepared on the aluminum alloy substrate by the above process, and the coating can have excellent comprehensive performance and good application prospect in the related field. The aluminum air electrode thus invented has excellent corrosion resistance and electrochemical performance. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The micro-morphology diagram of the rGO / AlSi10Mg powder.

[0034] Figure 2 The detailed micro-morphology diagram of the rGO-coated AlSi10Mg powder.

[0035] Figure 3 The micro-morphology diagram of the cold-sprayed rGO / AlSi10Mg air electrode.

[0036] Figure 4 The detailed micro-morphology diagram of the cold-sprayed rGO / AlSi10Mg air electrode.

[0037] Figure 5 The polarization curve of the three kinds of cold-sprayed additive manufacturing aluminum air electrodes after being immersed in 3.5 wt % NaCl solution for 2h.

[0038] Figure 6 The impedance spectrum curve of the three kinds of cold-sprayed additive manufacturing aluminum air electrodes after being immersed in 3.5 wt % NaCl solution for 2h.

[0039] Figure 7 The polarization curve of the three kinds of cold-sprayed additive manufacturing aluminum air electrodes after being immersed in 4M NaOH solution for 2h.

[0040] Figure 8 The impedance spectrum graph comparison of the three kinds of cold-sprayed additive manufacturing aluminum air electrodes after being immersed in 4M NaOH solution for 2h.

[0041] Figure 9The constant current polarization curves of three kinds of cold spray additive manufacturing aluminum air electrodes in 4M NaOH solution.

[0042] Figure 10 The impedance spectrum comparison of three kinds of cold spray additive manufacturing aluminum air electrodes after constant current polarization in 4M NaOH solution. DETAILED DESCRIPTION

[0043] The following are specific embodiments of the present application, and the technical solutions of the present application are further described in combination with the embodiments, but the present application is not limited to these embodiments.

[0044] The first aspect of the present application provides a surface pretreatment technology of an aluminum alloy substrate, including sand blasting treatment and surface cleaning, the sand blasting treatment removes impurities such as dust and oxide film on the surface of the aluminum alloy, and the surface cleaning removes residual impurities.

[0045] The present application relates to one of the technical solutions of the surface pretreatment technology of the aluminum alloy substrate, and at least has the following beneficial effects: The cleanliness of the aluminum alloy substrate is improved, which provides a basis for uniform dispersion of Al2O3 nanoparticles and effective coating of graphene oxide. The bonding force between the Al2O3 nanoparticles and the aluminum alloy substrate is enhanced, and the structural stability of the composite material is improved. By increasing the surface roughness of the substrate, the adhesion performance of the composite material and the substrate is optimized, which is beneficial to improve the application effect and service life of the composite material.

[0046] According to some embodiments of the present application, the carrier surface pretreatment includes sand blasting treatment and surface cleaning.

[0047] Sandblasting and surface cleaning is an effective surface modification technique. Adding this step in the preparation of composite materials can significantly improve the adhesion and stability of the coating, allowing the subsequent coating to adhere more firmly to the carrier surface. In addition, when preparing composite materials such as lithium batteries, fuel cells, etc., the cleanliness and roughness of the carrier surface are key factors affecting the performance of the coating. Sandblasting and surface cleaning as a step in the pretreatment of the carrier surface can serve as an improved coating-adhesion carrier, increase the surface roughness, and improve the bonding efficiency of the coating to the carrier, thereby increasing the overall performance of the composite material. Furthermore, in batteries and other electrochemical devices, carrier surface pretreatment is used to ensure uniform distribution of the coating and to transfer the required physical and chemical properties. Sandblasting and surface cleaning can help achieve uniform distribution of the coating, avoiding uneven accumulation of the coating in local areas, and reducing performance degradation and potential safety risks caused by uneven coating. Finally, especially when the composite material is subjected to long-term use and environmental influences, the carrier surface may be subjected to various stresses. The addition of sandblasting and surface cleaning can also increase the mechanical strength and chemical stability of the carrier, which is crucial for the long-term stable operation of the composite material.

[0048] The second aspect of the present application provides a graphene-coated AlSi10Mg composite powder.

[0049] One of the technical solutions of the present application relates to a graphene-coated AlSi10Mg composite powder, which has at least the following beneficial effects: The graphene-coated AlSi10Mg composite powder of the present application uses graphene oxide to coat AlSi10Mg alloy powder. Graphene oxide has good stability and barrier properties. Under its coating effect, the AlSi10Mg composite powder may have better oxidation resistance, corrosion resistance, and other properties in subsequent applications, thereby improving its use effect and service life.

[0050] According to some embodiments of the present application, the raw materials used to prepare the composite powder include: (1) 50 - 200 ml of GO dispersion liquid with a concentration of 0.1 - 0.3 mg / ml; (2) 10 - 20 g of AlSi10Mg alloy powder with a particle size of 30 - 50 μm.

[0051] According to some embodiments of the present application, the preparation method of the graphene-coated AlSi10Mg composite powder is: Place 50-200 ml of a 0.1-0.3 mg / ml GO dispersion in a suitable container. Disperse the graphene oxide thoroughly in deionized water using ultrasound and stir for 30-90 minutes. Then, add 10-20 g of 30-50 μm AlSi10Mg alloy powder to the GO dispersion and continue stirring for 20-30 minutes until the solution becomes transparent. Finally, wash and vacuum dry to obtain rGO / AlSi10Mg powder.

[0052] Graphene-coated AlSi10Mg composite powder can be produced through the above process, and the composite powder may exhibit good performance in related applications.

[0053] A third aspect of the present invention provides a method for preparing an rGO / AlSi10Mg / Al2O3 / 316 mixed powder, comprising the following steps: mechanically mixing weighed rGO / AlSi10Mg powder, aluminum oxide powder (Al2O3) and 316 stainless steel particles to obtain the rGO / AlSi10Mg / Al2O3 / 316 mixed powder.

[0054] One of the technical solutions of the present invention regarding the method for preparing rGO / AlSi10Mg / Al2O3 / 316 mixed powder has at least the following beneficial effects: The preparation method of the present invention is simple to operate, does not require complicated processes and expensive equipment, and has readily available raw materials. It can conveniently prepare mixed powders with specific properties and is suitable for industrial production.

[0055] In this mixed powder, rGO / AlSi10Mg powder provides certain basic properties, alumina powder (Al2O3) as a hard phase can improve the hardness and wear resistance of the mixed powder, and 316 stainless steel particles can give the mixed powder good strength and corrosion resistance. The three work together to make the mixed powder have better comprehensive performance.

[0056] According to some embodiments of the present invention, the weighed amount of the rGO / AlSi10Mg powder is 80-100 g.

[0057] According to some embodiments of the present invention, the relevant parameters of the aluminum oxide powder (Al2O3) are as follows: The average particle size of aluminum oxide powder (Al2O3) is 30-50 μm; The weighed amount of aluminum oxide powder (Al2O3) is 10-15 g.

[0058] According to some embodiments of the present invention, the relevant parameters of the 316 stainless steel particles are as follows: 316 stainless steel particles have an average particle size of 30-60 μm; The 316 stainless steel particles have a weight of 30-60 g.

[0059] According to some embodiments of the present application, the method for preparing the rGO / AlSi10Mg / Al2O3 / 316 mixed powder is specifically as follows: 80-100 g of rGO / AlSi10Mg powder is weighed, 10-15 g of aluminum oxide powder (Al2O3) having an average particle size of 30-50 μm is added as a hard phase, and 30-60 g of 316 stainless steel particles having an average particle size of 30-60 μm is weighed, and the rGO / AlSi10Mg powder, the aluminum oxide powder (Al2O3), and the 316 stainless steel particles are mechanically mixed to obtain the rGO / AlSi10Mg / Al2O3 / 316 mixed powder.

[0060] A fourth aspect of the present application provides an SP-rGO / AlSi10Mg coating formed by spraying a specific mixed powder on an aluminum alloy substrate by cold spraying technology.

[0061] One of the technical solutions of the SP-rGO / AlSi10Mg coating has at least the following beneficial effects: The SP-rGO / AlSi10Mg coating of the present application uses rGO / AlSi10Mg / Al2O3 / 316 mixed powder as raw material, rGO (reduced graphene oxide) has good flexibility and electrical conductivity, AlSi10Mg alloy has good mechanical properties, Al2O3 as a hard phase can improve the hardness of the coating, and 316 stainless steel particles can enhance the corrosion resistance of the coating. By cold spraying technology, these components are combined on the aluminum alloy substrate to form a coating that may have excellent comprehensive performance, such as good wear resistance, corrosion resistance, and mechanical properties, and can exhibit a long service life and stable performance in related applications.

[0062] According to some embodiments of the present application, the raw material used to prepare the coating is rGO / AlSi10Mg / Al2O3 / 316 mixed powder, which is prepared by a specific process.

[0063] According to some embodiments of the present application, the substrate of the coating is an aluminum alloy substrate.

[0064] According to some embodiments of the present application, the method for preparing the SP-rGO / AlSi10Mg coating is cold spraying technology. The specific process parameters are as follows: The compressed air temperature used in the spraying process is 200-600°C; The pressure used in the spraying process is 0.6-1.5 MPa; The spraying gun moving speed is 50-200 mm / s; The powder supply speed provided by the powder supply bucket is 0.1-0.5 g / s.

[0065] The specific operation process is: the obtained rGO / AlSi10Mg / Al2O3 / 316 mixed powder is sprayed on the aluminum alloy substrate by cold spraying technology according to the above process parameters, and the coating obtained after cold spraying is marked as SP-rGO / AlSi10Mg. The SP-rGO / AlSi10Mg coating can be prepared on the aluminum alloy substrate by the above process, which may have excellent comprehensive performance and good application prospect in the related field. The aluminum air electrode thus invented has excellent corrosion resistance and electrochemical performance.

[0066] The technical solutions of the present application will be better understood in combination with specific embodiments as follows. Example 1

[0067] Conventional sandblasting treatment is performed to remove dust and oxide film impurities on the surface of the aluminum alloy.

[0068] The surface of the aluminum alloy is cleaned to ensure cleanliness.

[0069] Prepare 50-200 ml of GO (graphene oxide) dispersion solution with a concentration of 0.1-0.3 mg / ml.

[0070] Disperse the graphene oxide in deionized water by ultrasonic and stir for 30-90 minutes.

[0071] Add 10-20 g of AlSi10Mg alloy powder with a particle size of 30-50 μm to the GO dispersion solution and stir for 20-30 minutes until the solution becomes transparent.

[0072] Wash and vacuum dry the mixed solution to obtain rGO / AlSi10Mg powder.

[0073] Weigh 80-100 g of rGO / AlSi10Mg powder.

[0074] Add 10-15 g of aluminum oxide powder (Al2O3) with an average particle size of 30-50 μm as a hard phase.

[0075] Weigh 30-60 g of stainless steel particles with an average particle size of 30-60 μm.

[0076] The rGO / AlSi10Mg powder, aluminum oxide powder (Al2O3), and 316 stainless steel particles were mechanically mixed to obtain the rGO / AlSi10Mg / Al2O3 / 316 mixed powder.

[0077] The rGO / AlSi10Mg / Al2O3 / 316 mixed powder was sprayed on an aluminum alloy substrate using cold spraying technology.

[0078] The cold spraying process parameters were set as follows: compressed air temperature of 200-600°C, pressure of 0.6-1.5 MPa, gun moving speed of 50-200 mm / s, and powder feeding speed of 0.1-0.5 g / s.

[0079] The coating obtained after cold spraying was marked as SP-rGO / AlSi10Mg.

[0080] The SP-rGO / AlSi10Mg coating was subjected to performance testing to evaluate its corrosion resistance.

[0081] The above steps describe in detail the entire process from surface treatment of the aluminum alloy substrate to the final coating preparation. Each step is crucial for the success of the experiment and needs to be strictly followed to ensure the accuracy and reliability of the experimental results.

[0082] Figure 1 、 Figure 2 The micro-morphology of the rGO / AlSi10Mg powder is shown in the figure. The powder surface has a heavy sense of touch, and obvious wrinkled nanosheets can be seen at the particle junction, which is a typical graphene morphology.

[0083] Figure 3 、 Figure 4 The micro-morphology of the cold-sprayed rGO / AlSi10Mg air electrode is shown in the figure. After tamping, the electrode surface is relatively dense.

[0084] Figure 5 The polarization curves of the three cold-sprayed additive-manufactured aluminum air electrodes after immersion in 3.5 wt % NaCl solution for 2 h are shown in the figure.

[0085] The polarization curves of the cold-sprayed aluminum, cold-sprayed graphene-coated aluminum, and in-situ tamped cold-sprayed graphene-coated aluminum electrodes after immersion in 3.5 wt % NaCl solution for 2 h are shown in the figure. The position of the polarization curve of the electrode with added graphene moves to the right and down relative to the cold-sprayed aluminum electrode, indicating that the corrosion current density decreases, but the passivation interval decreases. The addition of graphene enhances the depolarization ability of the coating.

[0086] Figure 6 The impedance spectrum curves of the three cold-sprayed additive-manufactured aluminum air electrodes after immersion in 3.5 wt % NaCl solution for 2 h are shown in the figure.

[0087] Impedance spectra of cold-sprayed aluminum, cold-sprayed graphene-coated aluminum, and in-situ compacted cold-sprayed graphene-coated aluminum electrodes after immersion in a 3.5 wt% NaCl solution for 2 hours. The addition of graphene increases the capacitive arc radius in the impedance spectrum, demonstrating enhanced corrosion protection. In-situ compaction further enhances the coating's corrosion protection by making it denser and more compact. Example 2

[0088] Perform conventional sandblasting to remove dust and oxide film impurities on the surface of the aluminum alloy.

[0089] Wash the aluminum alloy surface to ensure it is clean.

[0090] Prepare 50-200 ml of GO (graphene oxide) dispersion with a concentration of 0.1-0.3 mg / ml.

[0091] Graphene oxide was dispersed in deionized water by ultrasound and stirred for 30–90 min.

[0092] 10–20 g of AlSi10Mg alloy powder with a particle size of 30–50 μm was added to the GO dispersion and stirred for 20–30 min until the solution became transparent.

[0093] The mixed solution was washed and vacuum dried to obtain rGO / AlSi10Mg powder.

[0094] Weigh 80-100 g of rGO / AlSi10Mg powder.

[0095] 10-15 g of aluminum oxide powder (Al2O3) with an average particle size of 30-50 μm was added as a hard phase.

[0096] Weigh 30-60 g of stainless steel particles with an average particle size of 30-60 μm.

[0097] The rGO / AlSi10Mg powder, aluminum oxide powder (Al2O3), and 316 stainless steel particles were mechanically mixed to prepare rGO / AlSi10Mg / Al2O3 / 316 mixed powder.

[0098] The rGO / AlSi10Mg / Al2O3 / 316 mixed powder was sprayed on the aluminum alloy substrate using cold spraying technology.

[0099] Set the cold spray process parameters: compressed air temperature of 200-600 °C, pressure of 0.6-1.5 MPa, spray gun movement speed of 50-200 mm / s, and powder supply rate of 0.1-0.5 g / s.

[0100] The coating obtained after cold spraying is labeled as SP-rGO / AlSi10Mg.

[0101] The SP-rGO / AlSi10Mg coating is subjected to performance testing to evaluate its corrosion resistance.

[0102] The above steps detail the entire process from surface treatment of the aluminum alloy substrate to the final coating preparation. Each step is crucial to the success of the experiment and needs to be followed strictly to ensure the accuracy and reliability of the experimental results.

[0103] A regular sandblasting process is performed to remove dust and oxide film impurities from the surface of the aluminum alloy.

[0104] The surface of the aluminum alloy is cleaned to ensure cleanliness.

[0105] Prepare a GO (Graphene Oxide) dispersion solution with a concentration of 0.1-0.3 mg / ml in a volume of 50-200 ml.

[0106] Disperse the graphene oxide in deionized water using ultrasonication and stir for 30-90 minutes.

[0107] Add 10-20 g of AlSi10Mg alloy powder with a particle size of 30-50 μm to the GO dispersion solution and stir for 20-30 minutes until the solution becomes transparent.

[0108] Wash and vacuum dry the mixed solution to obtain rGO / AlSi10Mg powder.

[0109] Weigh 80-100 g of rGO / AlSi10Mg powder.

[0110] Add 10-15 g of aluminum oxide powder (Al2O3) with an average particle size of 30-50 μm as a hard phase.

[0111] Weigh 30-60 g of stainless steel particles with an average particle size of 30-60 μm.

[0112] Mechanically mix the above rGO / AlSi10Mg powder, aluminum oxide powder (Al2O3), and 316 stainless steel particles to obtain rGO / AlSi10Mg / Al2O3 / 316 mixed powder.

[0113] Use cold spraying technology to spray the rGO / AlSi10Mg / Al2O3 / 316 mixed powder on the aluminum alloy substrate.

[0114] Set the cold spraying process parameters: compressed air temperature 200-600°C, pressure 0.6-1.5 MPa, gun movement speed 50-200 mm / s, and powder feeding speed 0.1-0.5 g / s.

[0115] The coating obtained after cold spraying is labeled as SP-rGO / AlSi10Mg.

[0116] The SP-rGO / AlSi10Mg coating is subjected to performance testing to evaluate its corrosion resistance.

[0117] The above steps detail the entire process from surface treatment of the aluminum alloy substrate to the final coating preparation. Each step is crucial to the success of the experiment and needs to be followed strictly to ensure the accuracy and reliability of the experimental results.

[0118] Figure 7 Polarization curves of cold sprayed aluminum, cold sprayed graphene coated aluminum, and in-situ compacted cold sprayed graphene coated aluminum electrodes after 2h immersion in 4M NaOH solution. With only graphene added, the activity of the electrode in the solution increases, i.e., the electrode is more active, which can improve the current flux of the electrode, but it is easily consumed. After compaction, the electrode becomes more stable. The compaction of stainless steel makes the electrode structure more compact, and the graphene is more fine and evenly dispersed to form small electrode pairs with the aluminum matrix, reducing the polarization rate.

[0119] Figure 8 Impedance spectra of cold sprayed aluminum, cold sprayed graphene coated aluminum, and in-situ compacted cold sprayed graphene coated aluminum electrodes after 2h immersion in 4M NaOH solution. Consistent with the polarization curve results, the in-situ compacted cold sprayed graphene coated aluminum electrode has the best corrosion protection performance and the highest electrode stability, which is beneficial to prolonging the life of the electrode. Due to the inevitable pores produced by cold spraying, pitting corrosion of the electrode is inevitable. Example 3

[0120] Conduct a regular sandblasting process to remove dust and oxide film impurities from the surface of the aluminum alloy.

[0121] Clean the surface of the aluminum alloy to ensure cleanliness.

[0122] Prepare a 50-200ml GO (graphene oxide) dispersion solution with a concentration of 0.1-0.3 mg / ml.

[0123] Disperse the graphene oxide in deionized water by ultrasonic and stir for 30-90 minutes.

[0124] Add 10-20g of AlSi10Mg alloy powder with a particle size of 30-50μm to the GO dispersion solution and stir for 20-30 minutes until the solution becomes transparent.

[0125] Wash and vacuum dry the mixed solution to obtain rGO / AlSi10Mg powder.

[0126] Weigh 80-100g of rGO / AlSi10Mg powder.

[0127] Add 10-15 g of aluminum oxide powder (Al2O3) with an average particle size of 30-50 μm as a hard phase.

[0128] Weigh 30-60 g of stainless steel particles with an average particle size of 30-60 μm.

[0129] Mechanically mix the above rGO / AlSi10Mg powder, aluminum oxide powder (Al2O3), and 316 stainless steel particles to obtain rGO / AlSi10Mg / Al2O3 / 316 mixed powder.

[0130] Use cold spraying technology to spray the rGO / AlSi10Mg / Al2O3 / 316 mixed powder on the aluminum alloy substrate.

[0131] Set the cold spraying process parameters: compressed air temperature 200-600℃, pressure 0.6-1.5 MPa, gun moving speed 50-200 mm / s, and powder feeding speed 0.1-0.5 g / s.

[0132] The coating obtained after cold spraying is marked as SP-rGO / AlSi10Mg.

[0133] Test the performance of the SP-rGO / AlSi10Mg coating and evaluate its corrosion resistance.

[0134] The above steps describe in detail the entire process from surface treatment of the aluminum alloy substrate to the final coating preparation. Each step is crucial for the success of the experiment and needs to be strictly followed to ensure the accuracy and reliability of the experimental results.

[0135] Perform a regular sandblasting process to remove dust and oxide film impurities from the surface of the aluminum alloy.

[0136] Clean the surface of the aluminum alloy to ensure cleanliness.

[0137] Prepare 50-200 ml of GO (graphene oxide) dispersion solution with a concentration of 0.1-0.3 mg / ml.

[0138] Disperse graphene oxide in deionized water by ultrasonic and stir for 30-90 minutes.

[0139] Add 10-20 g of AlSi10Mg alloy powder with a particle size of 30-50 μm to the GO dispersion solution and stir for 20-30 minutes until the solution becomes transparent.

[0140] Wash and vacuum dry the mixed solution to obtain rGO / AlSi10Mg powder.

[0141] Take 80-100 g of rGO / AlSi10Mg powder.

[0142] Add 10-15 g of aluminum oxide powder (Al2O3) with an average particle size of 30-50 μm as a hard phase.

[0143] Take 30-60 g of stainless steel particles with an average particle size of 30-60 μm.

[0144] Mechanically mix the above rGO / AlSi10Mg powder, aluminum oxide powder (Al2O3), and 316 stainless steel particles to obtain rGO / AlSi10Mg / Al2O3 / 316 mixed powder.

[0145] Use cold spraying technology to spray the rGO / AlSi10Mg / Al2O3 / 316 mixed powder on an aluminum alloy substrate.

[0146] Set the cold spraying process parameters: compressed air temperature 200-600℃, pressure 0.6-1.5 MPa, gun moving speed 50-200 mm / s, and powder feeding speed 0.1-0.5 g / s.

[0147] The coating obtained after cold spraying is marked as SP-rGO / AlSi10Mg.

[0148] Test the performance of the SP-rGO / AlSi10Mg coating and evaluate its corrosion resistance.

[0149] The above steps describe in detail the entire process from surface treatment of the aluminum alloy substrate to the final coating preparation. Each step is crucial to the success of the experiment and needs to be strictly followed to ensure the accuracy and reliability of the experimental results.

[0150] Figure 9 The galvanostatic polarization curves of cold sprayed aluminum, cold sprayed graphene-coated aluminum, and in-situ compacted cold sprayed graphene-coated aluminum electrodes in 1M NaOH solution were obtained at a current density of 20 mA / cm 2 . Among them, the electrode potential of the in-situ compacted cold sprayed graphene-coated aluminum electrode is the highest, and the electrode potential first increases, then decreases, and then tends to be stable during the constant current process, which is related to the formation and dissolution of the passivation film.

[0151] Figure 10The impedance diagrams of the three kinds of cold spraying additive manufacturing aluminum air electrodes after constant current polarization in 4M NaOH solution are shown in the figure, from which it can be seen that the impedance spectra of the cold sprayed graphene coated aluminum electrode and the in-situ rammed cold sprayed graphene coated aluminum electrode form a semicircular capacitive arc after polarization, which shows that the surface forms a passivation film with certain protection ability after constant current polarization, while the cold sprayed aluminum electrode is polarized too fast, and the electrode is consumed too fast after constant current polarization, and has almost no protection effect.

[0152] The above has made a detailed description of the present application in combination with the embodiments, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge range possessed by those skilled in the art without departing from the purpose of the present application.

Claims

1. A method for preparing a cold spray in-situ compacted graphene / AlSi10Mg air electrode, characterized in that: The following steps are involved: (1) Substrate pretreatment: sandblasting and surface cleaning of the aluminum alloy deposition substrate to remove oxide film and impurities so that the surface roughness meets the requirements of the cold spraying process; (2) Preparation of composite powder: Graphene oxide (GO) was dispersed in deionized water and ultrasonicated for 30-90 min to form a 0.1-0.3 mg / ml GO dispersion. Add 10-20 g of AlSi10Mg alloy powder with a particle size of 30-50 μm and stir for 20-30 min until the solution becomes transparent. After washing and vacuum drying, rGO / AlSi10Mg powder is obtained. 80-100 g of rGO / AlSi10Mg powder was mechanically mixed with 10-15 g of Al2O3 powder with a particle size of 30-50 μm and 30-60 g of 316 stainless steel particles with a particle size of 30-60 μm to prepare rGO / AlSi10Mg / Al2O3 / 316 mixed powder; (3) Cold spray deposition: Using pretreated aluminum alloy as the substrate, the mixed powder was sprayed using the following parameters: compressed air temperature 200-600 °C, pressure 0.6-1.5 MPa, spray gun movement speed 50-200 mm / s, and powder supply speed 0.1-0.5 g / s to obtain the SP-rGO / AlSi10Mg coating.

2. The method according to claim 1, characterized in that The concentration of the GO dispersion in step (2) is 0.15-0.25 mg / ml, and the ultrasonic power is 200-400 W.

3. The method according to claim 1, characterized in that The Al2O3 powder in step (2) has a Mohs hardness of ≥8, and the chromium content of the 316 stainless steel particles is 16-18 wt%.

4. The method according to claim 1, wherein The preferred parameters of the cold spraying process in step (3) are: compressed air temperature 300-500 °C, pressure 1.0-1.2 MPa, and spray gun movement speed 100-150 mm / s.

5. A graphene / AlSi10Mg air electrode, characterized in that: Prepared by the method according to any one of claims 1 to 4, the coating is uniformly distributed with rGO conductive network, Al2O3 hard phase and stainless steel compaction phase.

6. A metal-air battery, characterized in that: Comprising the graphene / AlSi10Mg air electrode according to claim 5.

7. The metal-air battery according to claim 6, characterized in that The corrosion rate of the electrode in 3.5 wt% NaCl solution is ≤0.15 mm / year, and the polarization resistance is ≥1×10 5 Ω·cm².

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