Aluminum-air battery anode alloy material and preparation method

Abstract

This invention discloses an aluminum-air battery anode alloy material, the composition of which, by mass percentage, is: 0.70–1.10 wt% Zn, 0.09–0.14 wt% In, 0.07–0.11 wt% Sn, 0.05–0.08 wt% Ga, 0.03–0.05 wt% La, 0.015–0.035 wt% Zr, 0.015–0.025 wt% Ce, with unavoidable impurities totaling ≤0.05 wt%, and the balance being high-purity electrolytic aluminum. This invention solves the problems of easy detachment and peeling of the surface active structure and poor impedance matching in existing aluminum alloy anode materials.

Description

Technical Field

[0001] This invention relates to the field of aluminum-air battery anode alloy materials, and in particular to an aluminum-air battery anode alloy material and its preparation method. Background Technology

[0002] Aluminum-air batteries, with their outstanding advantages such as high energy density, wide availability of raw materials, environmental friendliness, and safety and reliability, have broad application prospects in portable energy storage, emergency power supply, and power sources. Aluminum alloy is the core anode material of aluminum-air batteries; its microstructure, compositional uniformity, and interfacial properties directly determine the battery's corrosion stability, discharge efficiency, and anode utilization rate, and are the key factors restricting the overall performance of aluminum-air batteries.

[0003] Currently, the aluminum alloy anode materials used in existing aluminum-air batteries still suffer from many inherent technical defects, which greatly limit the battery's service performance and lifespan. Firstly, the traditional aluminum alloy anode smelting and preparation process is crude, resulting in coarse grains and severe element segregation in the alloy matrix. Uneven distribution of activating elements within the matrix leads to uneven current distribution during electrode discharge. These structural defects easily cause localized preferential corrosion and the detachment of active structures from the electrode surface, resulting in significant loss of effective active material in the anode, drastically reducing the effective utilization rate of the aluminum alloy anode and shortening the battery's service life.

[0004] Secondly, existing conventional aluminum alloy anodes have poor substrate impedance matching and insufficient electrochemical adaptability. They exhibit significant polarization under high-current discharge conditions, with a prominent superposition effect of ohmic polarization and electrochemical polarization. This results in large fluctuations in battery output voltage, poor discharge stability, and insufficient high-power output capability, making it difficult to meet the actual application requirements of high-power and long-range applications.

[0005] Therefore, the aforementioned technical problems need to be solved. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, this invention proposes an aluminum-air battery anode alloy material and its preparation method, aiming to solve the problems of easy peeling and delamination of the surface active structure and poor impedance matching in existing aluminum alloy anode materials.

[0007] To solve the above-mentioned technical problems, the basic technical solution proposed by this invention is as follows:

[0008] An aluminum-air battery anode alloy material, the composition of which by mass percentage is: 0.70-1.10 wt% Zn, 0.09-0.14 wt% In, 0.07-0.11 wt% Sn, 0.05-0.08 wt% Ga, 0.03-0.05 wt% La, 0.015-0.035 wt% Zr, 0.015-0.025 wt% Ce, with unavoidable impurities totaling ≤0.05 wt%, and the balance being aluminum.

[0009] A method for preparing an aluminum-air battery anode alloy material, comprising preparing the anode alloy material by setting raw materials according to the composition ratio of the anode alloy material described above, specifically, by mass percentage: 0.70–1.10 wt% Zn, 0.09–0.14 wt% In, 0.07–0.11 wt% Sn, 0.05–0.08 wt% Ga, 0.03–0.05 wt% La, 0.015–0.035 wt% Zr, 0.015–0.025 wt% Ce, with unavoidable impurities totaling ≤0.05 wt%, and the balance being aluminum;

[0010] The specific preparation steps of the anode alloy material include:

[0011] The raw materials of the anode alloy are placed in a melting furnace and melted to obtain a melt.

[0012] The melt is directionally solidified and then homogenized by annealing to obtain an ingot.

[0013] The ingot is subjected to warm rolling and stress-relief annealing to obtain a coil.

[0014] Finally, the roll material is die-cut into shape.

[0015] Preferably, after the warm rolling and stress-relief annealing processes are completed, the roll material is subjected to electrospinning treatment, specifically as follows:

[0016] Surface pretreatment of the roll material;

[0017] The surface of the roll material is then modified using roll-to-roll electrospinning technology.

[0018] Finally, nitrogen gas with a purity of ≥99.999% is introduced to protect the electrospun roll material, followed by low-temperature curing.

[0019] Preferably, the electrospinning solution formulation used in the roll-to-roll electrospinning technology is as follows: by mass percentage, 12-15 wt% polyvinylidene fluoride, 3-5 wt% sulfonated polyether ether ketone, 1.5-2.5 wt% γ-Al2O3, 0.5-1.0 wt% boron-nitrogen co-doped carbon nanoparticles; the balance is N,N-dimethylformamide.

[0020] Preferably, the method for preparing the electrospinning solution is as follows:

[0021] The raw materials are prepared according to the electrospinning solution formula, and the raw materials are placed in a sealed container;

[0022] The raw materials were stirred at 200 r / min at room temperature for 12 hours.

[0023] The stirred raw materials were then ultrasonically dispersed for 30 minutes.

[0024] Finally, the ultrasonically dispersed raw materials are subjected to vacuum degassing for 10 minutes.

[0025] Preferably, the specific steps for melting the component raw materials of the anode alloy material in a melting furnace to obtain a melt are as follows:

[0026] Al, La, Ce, and Zr raw materials were pretreated to obtain Al-10La, Al-10Ce, and Al-5Zr aluminum-based master alloys and aluminum ingots with oxide scale removed.

[0027] The Al raw material is loaded into the furnace. After loading, the furnace is evacuated to maintain the pressure inside the furnace at 0.09 to 0.11 Pa, and the pressure is maintained for 10 minutes.

[0028] After holding the pressure, the furnace is heated to maintain the melting temperature at 730-750℃.

[0029] After the aluminum ingot is completely melted, keep it at that temperature for 10 minutes, and then degas and remove slag.

[0030] Add the materials in the following order: Zn→Sn→Ga→In→Al-10La, Al-10Ce→Al-5Zr. Keep the temperature for 5 minutes after each element is added.

[0031] After all raw materials have been added, argon gas with a purity of ≥99.999% is introduced into the melting furnace for protection, and the materials in the furnace are mechanically stirred at a stirring speed of 30 r / min for 30 to 35 minutes. When the melt temperature stabilizes at 732 to 748℃, it is ready for casting.

[0032] Preferably, the specific pretreatment steps for pretreating Al, La, Ce, and Zr raw materials are as follows:

[0033] The pretreatment steps for Al raw materials are as follows: the Al raw materials are treated by sandblasting to remove oxide scale, then the aluminum treated by sandblasting to remove oxide scale is ultrasonically cleaned with anhydrous ethanol, and finally the aluminum after ultrasonic cleaning is dried at 120℃ for 1 hour.

[0034] The pretreatment steps for La, Ce, and Zr raw materials are as follows: aluminum ingots are put into a melting furnace and the temperature is raised to 750-770℃ to melt the aluminum ingots. 0.03-0.05wt% La, 0.015-0.035wt% Zr, and 0.015-0.025wt% Ce are added to the melting furnace and the temperature is raised to 820-880℃. Then, argon gas with a purity ≥99.999% is introduced for protection and mechanical stirring is carried out for 20 minutes. Samples of the melt are taken before the furnace for rapid composition analysis and fine-tuning is carried out according to the analysis results. After obtaining Al-10La, Al-10Ce, and Al-5Zr, they are cast, milled, and crushed for later use.

[0035] Preferably, the directional solidification step is as follows: after the raw materials of each component of the anode alloy material are melted, the melt is poured into the copper mold at a flow rate of 0.35 to 0.55 kg / s. After the ingot is demolded, it is placed on a ventilated and air-cooled rack, and the cooling rate of the ingot is controlled at 15 to 20°C / s by adjusting the wind speed.

[0036] The homogenization annealing step is as follows: after the melt poured into the copper mold cools to room temperature to obtain an ingot, the ingot is placed in an annealing furnace, nitrogen gas with a purity of ≥99.999% is introduced, the temperature of the annealing furnace is raised to 420-450℃, and held for 6-8 hours.

[0037] Preferably, the low-temperature curing treatment employs segmented curing, and the specific process is as follows:

[0038] The first step involves preheating at 80℃ for 30 minutes.

[0039] The second stage involves curing at a constant temperature of 100℃ for 1.5 hours.

[0040] The third step involves placing the item in a 60℃ environment and allowing it to cool slowly for 30 minutes.

[0041] During the segmented curing process, nitrogen gas with a purity of ≥99.999% is introduced throughout the process, and the gas pressure inside the furnace is maintained at 0.01~0.025MPa.

[0042] Preferably, the surface pretreatment step is performed using a continuous online cleaning line.

[0043] The beneficial effects of this invention are:

[0044] The technical solution of this invention, through a reasonable and precise proportion, enables the Zn-In-Sn-Ga activation system to reduce grain boundary aggregation of activation elements and decrease the tendency for local pitting corrosion while ensuring the anodic activation potential and continuous discharge capability, thus achieving uniform activation and dissolution. Through the synergistic effect of the two rare earth elements, La and Ce, on the one hand, they can deoxidize and remove impurities from the melt, eliminating harmful inclusions and purifying the aluminum matrix; on the other hand, they act as grain refiners, breaking down the cast columnar crystal structure, refining the average grain size to ≤30μm, inhibiting intergranular corrosion, and improving discharge uniformity. Furthermore, during the melting process, dispersed Al3Zr intermetallic compound nanoprecipitates with a size ≤100nm are generated in situ, effectively pinning grain boundaries, inhibiting grain growth during heat treatment and rolling, strengthening matrix bonding, significantly reducing matrix spalling during discharge, and improving anodic utilization.

[0045] The specific collaborative mechanism between La and Ce is as follows: Ce and La have similar electronegativity. The composite deoxidation products in the composite rare earth melt have lower melting points and higher densities, making them easier to settle and remove impurities. However, the oxide particles generated by a single rare earth are extremely fine and difficult to separate when suspended in the aluminum melt. The synergistic effect of La and Ce is necessary to cause these fine particles to agglomerate into large clusters, increasing their weight and enabling rapid settling / enrichment, thus facilitating thorough impurity removal. Furthermore, La preferentially enriches at the solid-liquid interface front, hindering the rapid growth of nascent aluminum grains. Ce, on the other hand, can fill the vacancies at grain boundaries not covered by La, doubly blocking grain boundary channels and significantly limiting the segregation and precipitation of Zn / In / Sn / Ga activated atoms towards the grain boundaries. Simultaneously, single rare earth elements are prone to localized enrichment, forming microcathodes that induce pitting corrosion. The La+Ce composite can be uniformly dispersed at grain boundaries, passivating the grain boundary microcouples and allowing the activated elements to uniformly dissolve in the aluminum matrix. During discharge, the entire region is simultaneously activated and dissolved, preventing localized preferential corrosion and perforation. Attached Figure Description

[0046] Figure 1 This is a flowchart of a method for preparing an aluminum-air battery anode alloy material according to the present invention.

[0047] Figure 2 This is a smelting process flow diagram of a method for preparing an aluminum-air battery anode alloy material according to the present invention.

[0048] Figure 3 This is a flowchart of another method for preparing an aluminum-air battery anode alloy material according to the present invention.

[0049] Figure 4 The present invention discloses a low-temperature curing process flow chart for preparing an aluminum-air battery anode alloy material. Detailed Implementation

[0050] The following will be combined with the appendix Figure 1 To be continued Figure 4The technical solutions in the embodiments of the present invention have been clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0051] The anode (also known as the negative electrode) of an aluminum-air battery is the core "fuel" electrode of the battery. It is usually made of high-purity aluminum or aluminum alloys and plays a crucial role in providing electrons, undergoing oxidation reactions, and continuously consuming and releasing electrical energy. Generally speaking, aluminum has advantages such as extremely high energy density, negative electrode potential, abundant reserves, and low cost, making it one of the most industrially promising anode materials in metal-air batteries.

[0052] However, a dense oxide passivation film easily forms on the surface of pure aluminum, which makes anode activation difficult, discharge potential high, and utilization rate low. In alkaline electrolyte, aluminum will also undergo severe self-corrosion and hydrogen evolution, which will cause unnecessary anode loss, low coulombic efficiency, and hydrogen evolution safety risks. This is the fundamental problem restricting the practical application of aluminum anodes.

[0053] To resolve the conflict between passivation and hydrogen evolution, the anode of commercial aluminum-air batteries worldwide has been largely standardized as an Al–Zn–In–Sn–Ga pentagonal activation alloy system, which is currently the only mature, large-scale route. Zn can moderately shift the potential negatively, reduce hydrogen evolution, and improve corrosion morphology; In / Sn / Ga are elements with low hydrogen evolution overpotential, and through dissolution and redeposition mechanisms, they disrupt / inhibit the passivation film, continuously activating the aluminum matrix and ensuring stable discharge.

[0054] Although the pentagonal alloy has achieved basic activation and mass production, problems still exist, such as coarse grains, severe elemental segregation, discharge spalling, large polarization under high current, and unstable output. Among these, coarse grains and segregation lead to localized preferential corrosion, active layer detachment, and low anode utilization; furthermore, insufficient control of matrix impedance and interface conductivity results in significant polarization under high current, large voltage fluctuations, and poor stability under high power.

[0055] To address this, this invention proposes an aluminum-air battery anode alloy material and its preparation method. By optimizing the specific proportions of zinc (Zn), indium (In), tin (Sn), and gallium (Ga) and rationally designing the dosage relationships of each component, the anode alloy material ensures the anode activation potential and continuous discharge capability while reducing the aggregation of activation element grain boundaries, lowering the tendency for local pitting corrosion, and achieving uniform activation and dissolution. Simultaneously, lanthanum (La) and cerium (Ce) rare earth materials are added. Through the synergistic effect of the two rare earths, on the one hand, they deoxidize and remove impurities from the melt, eliminating harmful inclusions and purifying the aluminum matrix; on the other hand, they act as grain refiners, breaking down the cast columnar crystal structure, refining the average grain size to ≤30μm, suppressing intergranular corrosion, and improving discharge uniformity. In addition, the addition of zirconium (Zr) material allows for the in-situ generation of dispersed Al3Zr intermetallic compound nanoprecipitates with a size ≤100nm during the smelting process. These nanoprecipitates effectively pin grain boundaries, suppress grain growth during heat treatment and rolling, strengthen matrix bonding, significantly reduce matrix spalling during discharge, and improve anode utilization.

[0056] The specific mechanism is that both La and Ce are strong oxo / sulfo elements. La preferentially binds to suspended impurities such as Al2O3 and AlN, while Ce captures free metal impurities such as Fe and Si to form rare earth intermetallic compounds. The density of the composite inclusions is greater than that of the aluminum liquid, so they sink to the bottom and are removed as slag.

[0057] In the early stage of solidification, La acts as a heterogeneous nucleation core, inducing a large number of α-Al heterogeneous nucleations. In the middle and late stages of solidification, Ce enriches at grain boundaries, dragging solute atoms and hindering grain boundary migration and growth. This dual effect refines the cast grains from >80μm to ≤30μm, significantly reducing the electrolyte penetration channels caused by coarse grain boundaries and inhibiting intergranular flaking corrosion from the root.

[0058] Specifically, this invention proposes an aluminum-air battery anode alloy material, the composition of which, by mass percentage, is: 0.70–1.10 wt% Zn, 0.09–0.14 wt% In, 0.07–0.11 wt% Sn, 0.05–0.08 wt% Ga, 0.03–0.05 wt% La, 0.015–0.035 wt% Zr, 0.015–0.025 wt% Ce, with unavoidable impurities totaling ≤0.05 wt%, and the balance being aluminum.

[0059] Among them, Al (aluminum): This invention uses aluminum raw materials with a purity of ≥99.995%, with Al as the matrix framework to provide capacity for discharge generation; strict control of high purity reduces Fe / Si impurities in the microcouple, thereby reducing hydrogen evolution from strong alkali self-corrosion at the source.

[0060] Zn (zinc) is used to form a substitution solid solution in Al, negatively shifting the open circuit potential of aluminum, disrupting the continuous and dense Al(OH)3 passivation film on the surface, and improving initial discharge activity. Homogenization of the Zn solid solution can reduce the substrate potential difference and weaken localized micro-couple pitting corrosion. The purity of the Zn material in this invention is ≥99.99%.

[0061] In (In): In has a much lower potential than Al, preferentially enriching at passivation film breakage sites, generating an in-situ Al-In micro-activated phase, and tearing the alumina passivation layer; when combined with Sn and Ga, it reduces the activation overpotential, decreases concentration polarization during high-current discharge, and suppresses the sudden voltage drop during discharge. The purity of the In material in this invention is ≥99.99%.

[0062] Sn (tin): forms a low-melting-point multi-element active alloy phase with In / Ga, preferentially dissolving and breaking the passivation film during discharge; adsorbed on the aluminum surface to inhibit rapid redeposition into a dense passivation layer, thus achieving both continuous activation and static corrosion inhibition. The purity of the Sn material in this invention is ≥99.99%.

[0063] Ga (Gallium): Ga can form a liquid-phase wetting layer with Al in strong alkali. A small amount of Ga solid solution weakens the formation rate of the passivation film on the aluminum surface. When left to stand, it blocks the rapid erosion of the substrate by OH⁻ and, in conjunction with the surface spinning layer, inhibits self-corrosion and hydrogen evolution. In this invention, the purity of the Ga material is ≥99.99%.

[0064] La (lanthanum) and Ce (cerium): La (lanthanum) and Ce (cerium) are incorporated into the Al-Zn-In-Sn-Ga matrix in the form of Al-10La and Al-10Ce master alloys. In the early stage of solidification, La acts as a heterogeneous nucleation core, inducing a large number of α-Al heterogeneous nuclei. In the middle and late stages of solidification, Ce enriches at grain boundaries, dragging solute atoms and hindering grain boundary migration and growth. This dual effect refines the as-cast grains from >80μm to ≤30μm, significantly reducing the electrolyte penetration channels caused by coarse grain boundaries and inhibiting intergranular flaking corrosion from the source.

[0065] Zr (zirconium): Zr is mainly added to the Al-Zn-In-Sn-Ga-La-Ce alloy system in the form of Al-5Zr master alloy. During solidification, it generates dispersed Al3Zr particles, pinning grain boundaries and refining grains in the as-cast state. During smelting, the dispersed precipitates of Zr are uniformly distributed, reducing localized micro-galvanic corrosion and weakening the tendency for localized pitting corrosion under strong alkaline electrolytes. Combined with rare earth elements La and Ce, it synergistically regulates the corrosion morphology of the matrix, resulting in uniform anodic corrosion and reducing the static self-corrosion rate.

[0066] This invention optimizes the proportions of zinc (Zn), indium (In), tin (Sn), and gallium (Ga) to 0.70–1.10 wt% Zn, 0.09–0.14 wt% In, 0.07–0.11 wt% Sn, and 0.05–0.08 wt% Ga, respectively. This allows the anode alloy material to maintain the anode activation potential and continuous discharge capability while reducing the aggregation of activation elements at grain boundaries, lowering the tendency for local pitting corrosion, and achieving uniform activation and dissolution. By using 0.03–0.05 wt% La and 0.015–0.025 wt% Ce, the melt can be effectively deoxidized and impurities removed. Ce readily forms rare earth intermetallic compounds with Fe, Si, and S to eliminate harmful inclusions and purify the aluminum matrix. At the same time, both can act as grain refiners. On the one hand, La mainly plays a dominant role in heterogeneous nucleation. It can react with trace amounts of oxygen and nitrogen in the aluminum melt to generate high-melting-point microparticles. Since these microparticles have a low lattice mismatch with the α-Al matrix, they can act as a large number of heterogeneous nucleation nuclei, promoting a large number of nucleations in the alloy during solidification, thus laying the foundation for inherently fine grains. On the other hand, Ce dominates grain boundary dragging and inhibits growth. Due to its low solid solution limit, it easily accumulates at the solid-liquid interface or grain boundaries at the end of solidification to form a solute-rich layer, effectively hindering grain boundary migration and expansion, and inhibiting the mutual engulfment and coarsening of already formed fine grains. This breaks down the cast columnar crystal structure, refines the average grain size to ≤30μm, suppresses intergranular corrosion, and improves discharge uniformity. By using 0.015–0.035wt% Zr, it can better bond with aluminum, resulting in the in-situ formation of dispersed Al3Zr intermetallic compound nanoprecipitates with a size ≤100nm during the smelting process. These effectively pin grain boundaries, inhibit grain growth during heat treatment and rolling, strengthen matrix bonding, significantly reduce matrix spalling during discharge, and improve anode utilization.

[0067] Because Fe, Si, and Al form intermetallic compounds with a significantly higher potential than the aluminum matrix, numerous microscopic corrosion cells are formed in the strongly alkaline electrolyte. Excessive Fe content drastically increases the self-corrosion hydrogen evolution rate and amplifies the loss of static capacity. Simultaneously, it causes impurities to segregate at grain boundaries, resulting in the directional enrichment of active elements Zn / In / Ga, localized corrosion perforation, and a sharp drop in anode utilization. Therefore, it is crucial to strictly control the proportion of each impurity to prevent any single impurity from negatively impacting the final performance.

[0068] Specifically, among the impurities, Fe ≤ 0.02 wt%, Si ≤ 0.015 wt%, and other single impurities ≤ 0.01 wt%.

[0069] In some specific embodiments, the mass percentage of Zn can be 0.70%, 0.80%, 0.90%, 1.00%, 1.10%, etc.

[0070] In some specific embodiments, the mass percentage of In can be 0.09%, 0.10%, 0.11%, 0.12%, 0.13%, 0.14%, etc.

[0071] In some specific embodiments, the mass percentage of Sn can be 0.07%, 0.08%, 0.09%, 0.10%, 0.11%, etc.

[0072] In some specific embodiments, the mass percentage of Ga may be 0.05%, 0.06%, 0.07%, 0.08%, etc.

[0073] In some specific embodiments, the mass percentage of La can be 0.03%, 0.035%, 0.04%, 0.045%, 0.05%, etc.

[0074] In some specific embodiments, the mass percentage of Zr may be 0.015%, 0.020%, 0.025%, 0.030%, 0.035%, etc.

[0075] In some specific embodiments, the mass percentage of Ce may be 0.015%, 0.020%, 0.025%, etc.

[0076] like Figure 1 As shown, the preparation method of the aluminum-air battery anode alloy material formulation provided by the present invention includes the following steps:

[0077] The aforementioned anode alloy material is placed in a melting furnace for melting to obtain a melt. The specific components of the anode alloy material are as follows, by mass percentage: 0.70–1.10 wt% Zn, 0.09–0.14 wt% In, 0.07–0.11 wt% Sn, 0.05–0.08 wt% Ga, 0.03–0.05 wt% La, 0.015–0.035 wt% Zr, 0.015–0.025 wt% Ce, with unavoidable impurities totaling ≤0.05 wt%, and the balance being aluminum.

[0078] The melt is directionally solidified and then homogenized by annealing to obtain an ingot.

[0079] The ingot is subjected to warm rolling and stress-relief annealing to obtain a coil.

[0080] Finally, the roll material is die-cut into shape.

[0081] It should be noted that the present invention does not impose strict restrictions on the melting steps and melting environment of the anode alloy material. If a melt that meets the requirements can be melted, the order in which the various materials in the anode alloy material are added can be changed.

[0082] Specifically, in a preferred embodiment, to prevent problems such as uncontrolled element burn-off and inconsistent batch performance, the following steps must be strictly followed during the smelting of the aforementioned anode alloy material, such as... Figure 2 As shown:

[0083] Al, La, Ce, and Zr raw materials were pretreated to obtain Al-10La, Al-10Ce, and Al-5Zr aluminum-based master alloys and aluminum ingots with oxide scale removed.

[0084] The Al raw material is loaded into the furnace. After loading, the furnace is evacuated to maintain the pressure inside the furnace at 0.09 to 0.11 Pa, and the pressure is maintained for 10 minutes.

[0085] After holding the pressure, the furnace is heated to maintain the melting temperature at 730-750℃.

[0086] After the aluminum ingot is completely melted, keep it at that temperature for 10 minutes, and then degas and remove slag.

[0087] Add the materials in the following order: Zn→Sn→Ga→In→Al-10La, Al-10Ce→Al-5Zr. Keep the temperature for 5 minutes after each element is added.

[0088] After all raw materials have been added, argon gas with a purity of ≥99.999% is introduced into the melting furnace for protection, and the materials in the furnace are mechanically stirred at a stirring speed of 30 r / min for 30 to 35 minutes. When the melt temperature stabilizes at 732 to 748℃, it is ready for casting.

[0089] The specific pretreatment process for Al, La, Ce, and Zr raw materials is as follows:

[0090] The pretreatment steps for Al raw materials are as follows: the Al raw materials are treated by sandblasting to remove oxide scale, then the aluminum treated by sandblasting to remove oxide scale is ultrasonically cleaned with anhydrous ethanol, and finally the aluminum after ultrasonic cleaning is dried at 120℃ for 1 hour.

[0091] The pretreatment steps for La, Ce, and Zr raw materials are as follows: aluminum ingots are put into a melting furnace and the temperature is raised to 750-770℃ to melt the aluminum ingots. 0.03-0.05wt% La, 0.015-0.035wt% Zr, and 0.015-0.025wt% Ce are added to the melting furnace and the temperature is raised to 820-880℃. Then, argon gas with a purity ≥99.999% is introduced for protection and mechanical stirring is carried out for 20 minutes. Samples of the melt are taken before the furnace for rapid composition analysis and fine-tuning is carried out according to the analysis results. After obtaining Al-10La, Al-10Ce, and Al-5Zr, they are cast, milled, and crushed for later use.

[0092] It is important to note that the smelting process is completed using a vacuum induction melting furnace. Compared to conventional atmospheric melting equipment, the vacuum melting environment effectively avoids the oxidation, volatilization, and burn-off of reactive trace alloying elements such as In, Ga, La, and Ce during high-temperature melting. It also eliminates defects such as gas absorption and oxidation inclusions in the melt, ensuring the purity of the alloy melt. This solution preferably uses a 200kg-class ZG-200 model vacuum induction melting furnace. This equipment is equipped with an argon protection system, a melt stirring system, a vacuum detection system, and a high-precision constant temperature control system. The equipment's ultimate vacuum degree is ≤5Pa, and the temperature control accuracy can reach ±5℃, enabling precise and stable control of the entire melting process.

[0093] During the smelting process, the vacuum level inside the furnace is strictly controlled to be no less than 0.1 Pa throughout the entire process. An argon protection system further isolates the furnace from air, completely suppressing the oxidation and burn-off of reactive elements. The equipment's built-in melt stirring system continuously and uniformly stirs the aluminum-based melt, ensuring full fusion and uniform dispersion of all alloy components, effectively improving alloy composition segregation. Simultaneously, a high-precision constant temperature control system regulates the melt temperature in real time, keeping temperature fluctuations within ≤±5℃ throughout the smelting process, avoiding defects such as elemental agglomeration and grain coarsening caused by large temperature fluctuations.

[0094] It is worth noting that after the smelting is completed, the alloy melt needs to be sampled and tested. The composition deviation of each alloy element must be strictly controlled to be ≤±0.01wt%. This ensures that the composition of each batch of aluminum alloy matrix is ​​accurate, the structure is uniform, and the performance is consistent. This lays a good matrix foundation for the subsequent preparation of aluminum-air battery anode alloys with high stability, low polarization, and high utilization rate.

[0095] Before casting the melt, the mold needs to be pretreated. Specifically, the water-cooled crystallizer and the mold (usually a copper mold) are dried and preheated to remove moisture and impurities from the inner wall of the cavity, thus preventing the melt from rapidly cooling and producing disordered equiaxed crystals.

[0096] Preferably, the directional solidification step is as follows: after the raw materials of each component of the anode alloy are melted, the melt is poured into the copper mold at a flow rate of 0.35-0.55 kg / s. After the ingot is demolded, it is placed on a ventilated and air-cooled support. The cooling rate of the ingot is controlled at 15-20℃ / s by adjusting the air speed, so that the melt solidifies rapidly and finally the ingot is formed by cooling. Directional solidification achieves the directional preferential growth of grains along the thermal conduction direction and suppresses the transverse grain boundaries and transverse element segregation.

[0097] After the ingot cools to room temperature, it needs to undergo homogenization annealing. The specific steps are as follows: put it into an annealing furnace, fill it with pure nitrogen, heat it to 420-450℃, and hold it for 6-8 hours. The entire annealing process is protected by high-purity nitrogen to prevent surface oxidation.

[0098] In this process, 5N high-purity nitrogen with a purity of ≥99.999% and an oxygen content of less than 10ppm is used as a protective gas. First, nitrogen with a volume of 3 times that of the furnace is introduced to replace the air in the furnace cavity. During the production process, the furnace is maintained at a slight positive pressure of 0.015 to 0.03MPa to prevent air backflow. During the heat preservation stage, a micro-continuous nitrogen replenishment method is adopted. The total nitrogen consumption of this 500kg ingot single furnace for the entire process is 12 to 16Nm³.

[0099] It is important to note that after homogenization annealing, the ingots need to undergo quality inspection to select qualified products and reject unqualified ones. The inspection standard is that the ingots should be free of shrinkage cavities, cracks, and oxide inclusions, and the compositional uniformity deviation after annealing should be ≤0.03wt%.

[0100] During warm rolling, a four-roll reversible warm rolling mill is used to complete the warm rolling forming process of aluminum alloy billets. The four-roll reversible warm rolling mill has the advantages of uniform rolling force, high deformation stability, and controllable plate flatness. It can perform uniform and continuous plastic deformation processing on the directionally solidified alloy billet, effectively breaking up the coarse structure in the as-cast state, further refining the alloy grains, eliminating residual porosity and micro-defects inside the billet, and making the aluminum alloy matrix structure more dense and uniform. At the same time, the warm rolling equipment is equipped with a constant temperature heating system, an online thickness detection system, and a mesh belt continuous annealing furnace adapted to continuous coil production. It can realize integrated operation of warm rolling, closed-loop thickness control, and continuous annealing, which is highly matched with the mass production process requirements of coil-to-coil continuous electrostatic spinning.

[0101] In the specific processing, a constant-temperature heating system is used to precisely preheat and maintain the temperature of the rolls and alloy billets, ensuring a uniform and stable overall temperature of the billets. This avoids problems such as uneven stress, plate cracking, and thickness deviation caused by excessive temperature differences during rolling, thus improving the uniformity of plastic deformation of the alloy plates. A thickness online detection system monitors the thickness parameters of the rolled plates in real time, and the equipment's reversible rolling function enables multi-pass precise rolling, correcting rolling deviations in real time to ensure uniform thickness and high dimensional accuracy of the finished plates. After rolling, the plates are directly fed into a mesh belt continuous annealing furnace for continuous annealing treatment. This effectively eliminates work hardening and residual internal stress generated during warm rolling, stabilizes the alloy's microstructure, further improves the uniformity of alloy element dispersion, reduces internal defects and ohmic resistance, and ultimately obtains aluminum alloy anode coils with dense structure, uniform properties, and excellent mechanical and electrochemical stability. This provides a high-quality substrate material for subsequent surface electrospinning composite modification processes. Simultaneously, the entire process can achieve continuous and standardized mass production, significantly improving batch consistency and production efficiency.

[0102] In the specific processing, the alloy ingot, after directional solidification, is first preheated using a constant-temperature heating system. The preheating temperature is precisely controlled between 230 and 250°C. This temperature range allows the aluminum alloy billet to achieve excellent plasticity, eliminating the problems of poor plasticity and uneven deformation that easily occur in low-temperature rolling. After preheating, the alloy ingot under constant temperature conditions undergoes multi-pass continuous warm rolling. The reduction in each pass is strictly controlled to be ≤15%. A small reduction and multi-pass progressive rolling method is adopted to avoid problems such as stress concentration, surface and internal cracking, and deformation defects caused by excessive reduction in a single pass. This ensures that the billet gradually completes plastic deformation and that the rolling process is stable and controllable. During the rolling process, the thickness parameters of the rolled plate are dynamically monitored in real time by an online thickness detection system. Combined with the equipment's reversible rolling function, multi-pass precise rolling is achieved, and rolling deviations are corrected in real time to ensure that the finished plate has uniform thickness and high dimensional accuracy.

[0103] The specific steps of stress-relief annealing are as follows: the rolled coil is continuously fed into the annealing furnace and kept in a heat-preserving environment at a temperature of 310-330℃ for 2-2.5 hours to eliminate the internal stress of rolling, ensure the flatness of the sheet, and then flatten and rewind after annealing.

[0104] Throughout the entire process of warm rolling aluminum alloy anode coil forming, strict quality control points are established to standardize and manage the dimensional accuracy, surface condition, and overall flatness of the rolled coil, ensuring batch consistency and compatibility with subsequent modification processes. Preferably, the thickness tolerance of the warm-rolled aluminum alloy anode coil is strictly controlled to ≤±0.01mm. This ultra-high precision thickness control effectively avoids differences in discharge current density distribution caused by uneven thickness in the coil, preventing issues such as abnormal local polarization and uneven corrosion, and ensuring a uniform and stable overall electrochemical response of the anode. Simultaneously, the flatness of the coil is controlled to ≤0.5mm / m to ensure overall flatness, freedom from warping and wavy deformation. This facilitates subsequent feeding, coating, and forming in roll-to-roll continuous electrospinning mass production equipment, preventing process defects such as uneven coating thickness, localized missed coating, and poor fiber film adhesion caused by coil deformation.

[0105] In addition, the finished coil must meet the quality standards of no peeling, no cracks, and no deformation in appearance and overall condition, eliminating microscopic damage to the substrate and stress concentration caused by defects in the rolling process. A coil free of peeling and cracks can prevent localized accumulation and preferential corrosion of the electrolyte at defect locations, effectively improving the corrosion resistance and discharge life of the aluminum alloy anode.

[0106] After warm rolling and homogenization annealing, the material enters the die-cutting process. This process is mainly used to cut the roll material into preset sizes, and therefore there are various ways to achieve this, which will not be elaborated here.

[0107] In one specific implementation, a high-speed precision die-cutting machine equipped with high-precision molds is used for standardized die-cutting processing. The equipment positioning accuracy can reach ±0.1mm, ensuring the consistency of electrode dimensions and forming accuracy. During processing, continuous anode rolls are die-cut as a whole according to the design dimensions to produce standard-specification aluminum-air battery anode electrodes in batches. During the die-cutting process, burrs, flash, and other processing defects generated at the edges of the electrodes are removed simultaneously to ensure that the edges of the electrodes are flat and regular. After die-cutting, all formed electrodes are screened one by one by a fully automatic appearance sorting table. Defective products with appearance defects such as film peeling, scratches, deformation, and stains are accurately sorted and rejected. Only qualified electrodes with complete appearance, uniform coating, and standard dimensions are retained for centralized collection, effectively ensuring the consistency of the appearance quality and electrochemical use of the finished electrodes.

[0108] Finally, the selected qualified anode sheets undergo standardized finished product protection treatment and warehousing management. The qualified anode sheets are neatly packed into dedicated moisture-proof aluminum foil bags and sealed using a vacuum heat-sealing method. This vacuum seal effectively isolates the anode sheets from air, moisture, and dust, preventing surface dampness, secondary oxidation, and contamination during handling and storage, thus stabilizing the anode surface activation state and coating structure performance. Simultaneously, the finished products are stored in a light-proof, dry environment to avoid material performance degradation caused by light and temperature / humidity fluctuations, maximizing the preservation of the high activity and low polarization characteristics of the aluminum anode, and ensuring the long-term storage stability of batch products and the reliability of battery assembly and use.

[0109] Specifically, the performance advantages of the technical solution of this invention will be visually demonstrated through three sets of comparative experiments below.

[0110] The experimental and control groups were both tested using the following methods:

[0111] Self-corrosion rate detection: Static weight loss method, 4 mol / L KOH electrolyte, constant temperature at 25℃, soaking for 72 h, calculate the weight loss rate per unit area.

[0112] Discharge performance testing: Blue Battery testing system, three-electrode system, platinum sheet counter electrode, mercury oxide reference electrode, constant current discharge test stable potential, polarization curve.

[0113] Anode utilization rate test: After complete discharge, collect corrosion products and residual matrix, weigh them and calculate the effective discharge aluminum ratio.

[0114] Bond strength testing: Cross-cut test + pull-out tester to test the bonding strength between the composite layer and the substrate.

[0115] Microstructure analysis: metallographic microscope (grain size), scanning electron microscope (SEM) (surface morphology, precipitates), energy dispersive spectroscopy (EDS) (composition distribution).

[0116] The preparation process used in the experimental group is as follows:

[0117] The Al raw material is treated by sandblasting to remove the oxide scale, and then the aluminum treated by sandblasting is ultrasonically cleaned with anhydrous ethanol. Finally, the ultrasonically cleaned aluminum is dried at 120℃ for 1 hour and then left to use.

[0118] Aluminum ingots are placed in a melting furnace and heated to 750–770°C to melt them. 0.03–0.05 wt% La, 0.015–0.035 wt% Zr, and 0.015–0.025 wt% Ce are added to the melting furnace, and the temperature is raised to 820–880°C. Then, argon gas with a purity ≥99.999% is introduced for protection and mechanical stirring is performed for 20 minutes. Samples of the melt are taken before the furnace for rapid composition analysis, and fine adjustments are made based on the analysis results. After obtaining Al-10La, Al-10Ce, and Al-5Zr, the mixture is cast, milled, and crushed for later use.

[0119] The material is smelted in a vacuum induction furnace, model ZG-200. The Al raw material is loaded into the furnace, and after loading, the furnace is evacuated to maintain the pressure inside the furnace at 0.09 to 0.11 Pa, and the pressure is maintained for 10 minutes.

[0120] After holding the pressure, the furnace is heated to maintain the melting temperature at 730-750℃.

[0121] After the aluminum ingot is completely melted, keep it at that temperature for 10 minutes, and then degas and remove slag.

[0122] Add the materials in the following order: Zn→Sn→Ga→In→Al-10La, Al-10Ce→Al-5Zr. Keep the temperature for 5 minutes after each element is added.

[0123] After all raw materials have been added, argon gas with a purity of ≥99.999% is introduced into the melting furnace for protection, and the materials in the furnace are mechanically stirred at a stirring speed of 30 r / min for 30 to 35 minutes. When the melt temperature stabilizes at 732 to 748℃, it is ready for casting.

[0124] The casting is carried out using a directional solidification casting machine, model DZ-300. The melt is poured into the copper mold at a flow rate of 0.35 to 0.55 kg / s. After the ingot is demolded, it is placed on a ventilated and air-cooled rack. The cooling rate of the ingot is controlled at 15 to 20℃ / s by adjusting the air speed, so that the melt solidifies quickly and finally the ingot is formed by cooling.

[0125] After the ingot cools to room temperature, it needs to undergo homogenization annealing treatment. A nitrogen-protected annealing furnace, model TX-450, is used. The specific steps are as follows: the ingot is loaded into the annealing furnace, filled with nitrogen gas with a purity of ≥99.999%, heated to 420~450℃, and held for 6~8 hours. The entire annealing process is protected by high-purity nitrogen gas to prevent surface oxidation.

[0126] The aluminum alloy billet is warm rolled using a four-roll reversible warm rolling mill (model SR-300), and the rolled coil is continuously fed into an annealing furnace and held at a temperature of 310-330℃ for 2-2.5 hours to eliminate rolling internal stress, finally obtaining the coil.

[0127] Standardized die-cutting processing of roll materials is carried out using a high-speed precision die-cutting machine (model MQ-300) with matching high-precision molds.

[0128] Benchmark control group, conventional commercial Al-Zn-In-Sn-Ga anode alloy:

[0129] Formula: Zn 1.5wt%, In 0.2wt%, Sn 0.15wt%, Ga 0.1wt%, balance aluminum.

[0130] Performance test results:

[0131] Self-corrosion rate: 0.27 mg / (cm²·h); Steady-state potential at 100 mA / cm²: -1.22 V; Anode utilization rate: 71.3%; Capacity loss after 30 days of static setting: 18.7%; Polarization voltage drop at 200 mA / cm²: >120 mV; Immersion in 6 mol / L KOH for 7 days: Severe pitting corrosion of the substrate and flaking of the surface layer.

[0132] Experiment 1

[0133] Alloy composition (wt%): Zn 0.90, In 0.11, Sn 0.09, Ga 0.065, La 0.04, Ce 0.02, Zr 0.025; impurities ≤0.05% (Fe ≤0.02, Si ≤0.015), balance being Al with purity ≥99.995%.

[0134] Performance test results:

[0135] Self-corrosion rate: 0.20 mg / (cm²·h); Discharge potential at 100 mA / cm²: -1.27 V; Anode utilization rate: 79.8%; Capacity loss after 30 days of static storage at room temperature: 9.2%; Polarization voltage drop at 200 mA / cm²: 78 mV; Immersion in 6 mol / L KOH for 7 days: slight pitting corrosion, no large-scale peeling.

[0136] Experiment 2

[0137] Alloy composition (wt%): Zn 1.05%, In 0.13%, Sn 0.10%, Ga 0.075%, La 0.045%, Ce 0.02%, Zr 0.03%; impurities ≤0.05% (Fe ≤0.02%, Si ≤0.015%), balance being Al with a purity ≥99.995%.

[0138] Performance test results:

[0139] Self-corrosion rate: 0.21 mg / (cm²·h); Discharge potential at 100 mA / cm²: -1.28 V; Anode utilization rate: 78.9%; Static loss after 30 days: 9.8%; Polarization voltage drop at 200 mA / cm²: 72 mV; Immersion in 6 mol / L KOH for 7 days: Localized minor pitting, no peeling or flaking.

[0140] Experiment 3

[0141] Alloy composition (wt%): Zn 0.75, In 0.095, Sn 0.075, Ga 0.055, La 0.035, Ce 0.025, Zr 0.02; impurities ≤0.05% (Fe≤0.02, Si≤0.015), balance is Al with purity ≥99.995%.

[0142] Performance test results:

[0143] Self-corrosion rate: 0.18 mg / (cm²·h); Discharge potential at 100 mA / cm²: -1.26 V; Anode utilization rate: 80.5%; Capacity loss after 30 days of static storage: 7.9%; Polarization voltage drop at 200 mA / cm²: 81 mV; Immersion in 6 mol / L KOH for 7 days: Only slight uniform corrosion on the surface, no perforation or peeling.

[0144] The performance comparison is as follows:

[0145] Self-corrosion rate (mg / (cm²·h)) 0.27 0.20 0.21 0.18 Discharge potential (V) of 100 mA / cm² -1.22 -1.27 -1.28 -1.26 Anode utilization rate (%) 71.3 79.8 78.9 80.5 30-day static capacity loss (%) 18.7 9.2 9.8 7.9 200mA / cm² polarization voltage drop >120mV 78mV 72mV 81mV Soaking in 6 mol / L KOH for 7 days Severe corrosion and large areas of peeling Minor pitting without peeling Tiny pits without detachment Micro-scale uniform corrosion

[0146] As can be seen from the table, the properties of the anode alloy material of the present invention are all improved compared with those of currently commercially available anode alloys, and can solve the problems in the background art.

[0147] To further optimize the problem of spontaneous hydrogen evolution corrosion of aluminum substrates with alkaline electrolytes under standby conditions, this invention proposes a technical solution using an electrospun nanocomposite protective layer to protect the anode alloy. Relying on the porous, interconnected structure of the coating and the ion screening effect of its functional components, the coating enables rapid penetration of electrolyte ions during battery operation and discharge, ensuring normal electrochemical reactions. During standby, it effectively blocks the continuous erosion of the aluminum substrate by strong alkaline media, achieving a synergistic function of efficient discharge conduction and strong corrosion protection under standby conditions. This significantly suppresses the self-corrosion reaction of the aluminum anode at the interface protection level, and significantly reduces battery self-discharge loss and ineffective substrate loss during standby.

[0148] In detail, surface modification is achieved by electrospinning roll materials that have undergone warm rolling and homogenization annealing using roll-to-roll electrospinning technology, such as... Figure 3 As shown, the specific steps include:

[0149] Surface pretreatment of the roll material;

[0150] The surface of the roll material is then modified using roll-to-roll electrospinning technology.

[0151] Finally, nitrogen protection and low-temperature curing treatment are performed.

[0152] This process uses vaporized 5N high-purity liquid nitrogen with a purity ≥99.999% as a protective gas, and the online oxygen content in the furnace is controlled at 100ppm or below. During continuous furnace operation, at least 3 times the furnace volume of nitrogen is introduced to complete the replacement in the initial stage. During the constant temperature curing stage, a small amount of continuous pressure nitrogen is added. Under the condition of an online speed of 0.2m / min, the nitrogen consumption per unit length of the roll material is 0.8~1.2Nm³ / m.

[0153] The surface pretreatment is mainly used to remove surface impurities and oxide layers, activate the substrate surface, and optimize the substrate surface adhesion and electrochemical uniformity. This avoids preferential corrosion and peeling off of the anodic area, improves the adhesion of the nanocomposite protective layer, reduces electrode polarization, and improves the stability of high-power discharge. Therefore, the specific operation method of surface pretreatment is not limited, as long as the desired effect is achieved.

[0154] In one specific implementation, during surface pretreatment, a fully automated continuous ultrasonic cleaning line is used to complete the entire continuous operation, eliminating the need for traditional intermittent manual operation. This effectively ensures uniform and consistent surface cleanliness across the entire roll of material, meeting the requirements of continuous mass production processes. The fully automated continuous ultrasonic cleaning line is equipped with an alkaline washing tank, an acid washing tank, a multi-stage countercurrent rinsing tank, a hot air drying oven, and an online dust removal system, enabling integrated continuous processing of degreasing, deoxidation, activation, rinsing, drying, and dust removal.

[0155] Specifically, the process begins with alkaline washing to remove oil. A 5% sodium hydroxide aqueous solution is used, with the washing tank temperature controlled at 60°C. The online washing time for the coil is 3 minutes, effectively removing rolling oil stains, grease deposits, and a loose oxide layer from the coil surface. After alkaline washing, the coil undergoes an acid pickling and polishing process. An aqueous solution of 10% nitric acid and 2% hydrofluoric acid is used, and the coil is acid-washed online at room temperature for 1 minute. This further thoroughly removes the dense oxide scale from the coil surface, etches and activates the aluminum alloy substrate surface, and improves the surface activity and adhesion of subsequent coatings.

[0156] After pickling, a three-stage deionized water countercurrent rinsing process is used. The rinsing water has a conductivity of ≤5μS / cm. Through multi-stage countercurrent displacement, residual acid and alkali agents and trace corrosion products on the surface of the roll material are thoroughly removed, avoiding subsequent rusting, uneven surface, and coating peeling caused by residual liquid. After rinsing, the roll material is placed in a hot air drying oven for constant temperature drying. The drying temperature is set to 100℃ and the drying is carried out for 5 minutes to ensure that the surface of the roll material is completely dry and free of water droplets, water stains, and residual impurities.

[0157] This process involves strict surface quality control checkpoints. After cleaning and drying, the hydrophilic angle of the aluminum alloy coil surface is ≤15°, the surface is clean overall, free of oil stains, oxide spots, and chemical residues, and the surface is uniformly activated. Qualified coils after drying are immediately transferred to a closed, dust-free workshop for storage and circulation, effectively isolating them from airborne dust and moisture erosion, preventing secondary oxidation and contamination of the substrate surface, ensuring stable surface condition and high batch consistency, and providing a high-cleanliness, high-activity, and high-adhesion high-quality substrate surface for subsequent roll-to-roll electrospinning coating preparation.

[0158] When performing roll-to-roll electrospinning on roll-to-roll materials, the electrospinning solution formula used is as follows:

[0159] 12–15 wt% polyvinylidene fluoride, 3–5 wt% sulfonated polyether ether ketone, 1.5–2.5 wt% γ-Al₂O₃, 0.5–1.0 wt% boron-nitrogen co-doped carbon nanoparticles; balance N,N-dimethylformamide.

[0160] Specifically, the electrospinning solution preparation method is as follows: the material is placed in a sealed container and stirred at a speed of 200 r / min for 12 hours at room temperature, followed by ultrasonic dispersion for 30 minutes, and then vacuum degassing for 10 minutes to remove air bubbles from the system.

[0161] In one specific embodiment, the present invention uses a fully automatic electrostatic spinning mass production equipment of model ES-R200. The entire production line integrates an unwinding system, a constant temperature and humidity sealed spinning chamber, a multi-nozzle spinning system, a high-voltage power supply system, a traction winding system, and an online thickness detection system. The equipment can realize fully sealed continuous spinning operation, effectively avoiding the interference of external environmental dust and temperature and humidity fluctuations on the spinning film quality. Moreover, the maximum spinning width is adapted to the 200mm standard anode roll specification, which fully meets the needs of large-scale continuous production.

[0162] Before spinning, the environment of the sealed spinning chamber is controlled to maintain a stable and controllable process environment. Specifically, the spinning temperature is controlled at 26–28℃ and the relative humidity at 45%–50%. Simultaneously, the chamber is maintained as a Class 10,000 cleanroom environment to ensure uniform nanofiber formation, free from impurities, and to prevent defects such as broken fibers, tangled fibers, and fiber agglomeration. The spinning process employs high-voltage electrostatic spinning, with a high voltage of 18–20 kV. The receiving roller is grounded throughout the process to create a stable and uniform high-voltage electrostatic field. The distance between the nozzle and the receiving roller is precisely controlled at 14–16 cm to ensure stable stretching and regular formation of the spinning jet.

[0163] Continuous spinning is achieved using a multi-nozzle synchronous feeding method. A precision injection pump precisely controls the spinning solution propulsion rate to 0.5–0.7 mL / h, with strict control over the flow rate deviation of each nozzle to ≤±0.02 mL / h. This ensures uniform and synchronized spinning solution supply across all areas, preventing localized fiber accumulation or incomplete coating. Simultaneously, the roll traction speed is set to 0.2 m / min. This low-speed, uniform traction ensures the nanofibers are deposited layer by layer and uniformly on the roll surface, achieving a coating effect without any missed areas, accumulation, or uneven thickness.

[0164] In addition, this process sets strict quality control standards for the spinning process, monitoring the spinning status and coating precision throughout the entire process. It requires that the spinning process be continuous and stable, without broken fibers or nozzle blockage, and that the nanocomposite fiber layer deposited on the surface of the roll be uniform and dense. The coating thickness is monitored in real time by the online thickness detection system on the equipment, and the thickness deviation of the finished coating is strictly controlled to be ≤±0.5μm. This ensures that the protective layer thickness on the surface of the entire anode roll is uniform and the structure is consistent, providing a reliable interface structure foundation for the anode to achieve stable ion selective conduction, strong alkali resistance and corrosion resistance and low self-loss performance.

[0165] Preferably, the low-temperature curing treatment employs segmented curing, such as... Figure 4 As shown, the specific process is as follows:

[0166] The first step involves preheating at 80℃ for 30 minutes.

[0167] The second stage involves curing at a constant temperature of 100℃ for 1.5 hours.

[0168] The third step involves placing the item in a 60℃ environment and allowing it to cool slowly for 30 minutes.

[0169] During the segmented curing process, high-purity nitrogen is introduced throughout to prevent oxidation of the aluminum substrate at high temperatures.

[0170] After low-temperature curing, the quality of the roll material must be inspected to ensure that the composite layer is free from cracks, peeling, and pinholes after curing, and that the bonding strength with the substrate is ≥5MPa, with the thickness stably controlled between 5 and 8μm.

[0171] The performance advantages of the technical solution of this invention are visually demonstrated through three sets of comparative experiments.

[0172] The experimental and control groups were both tested using the following methods:

[0173] Self-corrosion rate detection: Static weight loss method, 4 mol / L KOH electrolyte, constant temperature at 25℃, soaking for 72 h, calculate the weight loss rate per unit area.

[0174] Discharge performance testing: Blue Battery testing system, three-electrode system, platinum sheet counter electrode, mercury oxide reference electrode, constant current discharge test stable potential, polarization curve.

[0175] Anode utilization rate test: After complete discharge, collect corrosion products and residual matrix, weigh them and calculate the effective discharge aluminum ratio.

[0176] Bond strength testing: Cross-cut test + pull-out tester to test the bonding strength between the composite layer and the substrate.

[0177] Microstructure analysis: metallographic microscope (grain size), scanning electron microscope (SEM) (surface morphology, precipitates), energy dispersive spectroscopy (EDS) (composition distribution).

[0178] The preparation process used in the experimental group is as follows:

[0179] The Al raw material is treated by sandblasting to remove the oxide scale, and then the aluminum treated by sandblasting is ultrasonically cleaned with anhydrous ethanol. Finally, the ultrasonically cleaned aluminum is dried at 120℃ for 1 hour and then left to use.

[0180] Aluminum ingots are placed in a melting furnace and heated to 750–770°C to melt them. 0.03–0.05 wt% La, 0.015–0.035 wt% Zr, and 0.015–0.025 wt% Ce are added to the melting furnace, and the temperature is raised to 820–880°C. Then, argon gas with a purity ≥99.999% is introduced for protection and mechanical stirring is performed for 20 minutes. Samples of the melt are taken before the furnace for rapid composition analysis, and fine adjustments are made based on the analysis results. After obtaining Al-10La, Al-10Ce, and Al-5Zr, the mixture is cast, milled, and crushed for later use.

[0181] The material is smelted in a vacuum induction furnace, model ZG-200. The Al raw material is loaded into the furnace, and after loading, the furnace is evacuated to maintain the pressure inside the furnace at 0.09 to 0.11 Pa, and the pressure is maintained for 10 minutes.

[0182] After holding the pressure, the furnace is heated to maintain the melting temperature at 730-750℃.

[0183] After the aluminum ingot is completely melted, keep it at that temperature for 10 minutes, and then degas and remove slag.

[0184] Add the materials in the following order: Zn→Sn→Ga→In→Al-10La, Al-10Ce→Al-5Zr. Keep the temperature for 5 minutes after each element is added.

[0185] After all raw materials have been added, argon gas with a purity of ≥99.999% is introduced into the melting furnace for protection, and the materials in the furnace are mechanically stirred at a stirring speed of 30 r / min for 30 to 35 minutes. When the melt temperature stabilizes at 732 to 748℃, it is ready for casting.

[0186] The casting is carried out using a directional solidification casting machine, model DZ-300. The melt is poured into the copper mold at a flow rate of 0.35 to 0.55 kg / s. After the ingot is demolded, it is placed on a ventilated and air-cooled rack. The cooling rate of the ingot is controlled at 15 to 20℃ / s by adjusting the air speed, so that the melt solidifies quickly and finally the ingot is formed by cooling. After the ingot cools to room temperature, it needs to undergo homogenization annealing treatment. A nitrogen-protected annealing furnace, model TX-450, is used. The specific steps are as follows: the ingot is loaded into the annealing furnace, filled with nitrogen gas with a purity of ≥99.999%, heated to 420~450℃, and held for 6~8 hours. The entire annealing process is protected by high-purity nitrogen gas to prevent surface oxidation. The aluminum alloy billet is warm rolled using a four-roll reversible warm rolling mill (model SR-300), and the rolled coil is continuously fed into an annealing furnace and held at a temperature of 310-330℃ for 2-2.5 hours to eliminate rolling internal stress, finally obtaining the coil.

[0187] The fully automatic continuous ultrasonic cleaning line, model CX-300, is used to perform surface pretreatment on roll materials, and the entire process is completed continuously.

[0188] A fully automated electrospinning mass production equipment, model ES-R200, was selected. The roll material was then surface-modified using roll-to-roll electrospinning technology. The electrospinning solution formulation consisted of 12–15 wt% polyvinylidene fluoride, 3–5 wt% sulfonated polyether ether ketone, 1.5–2.5 wt% γ-Al₂O₃, and 0.5–1.0 wt% boron-nitrogen co-doped carbon nanoparticles; the balance being N,N-dimethylformamide. The electrospinning composite layer thickness was 6 μm.

[0189] A continuous nitrogen curing oven, model GH-200, was used for nitrogen protection and staged low-temperature curing treatment. Specifically, the first stage involved preheating at 80℃ for 30 minutes; the second stage involved constant temperature curing at 100℃ for 1.5 hours; and the third stage involved slow cooling at 60℃ for 30 minutes. Standardized die-cutting processing of roll materials is carried out using a high-speed precision die-cutting machine (model MQ-300) with matching high-precision molds.

[0190] Control group: Traditional commercial Al-Zn-In-Sn-Ga anode

[0191] The composition, by weight percentage, is: Zn 1.5%, In 0.2%, Sn 0.15%, Ga 0.1%, with the balance being Al.

[0192] Performance test results:

[0193] Performance data: Self-corrosion rate: 0.27 mg / (cm²·h), 100 mA / cm² discharge potential: -1.22 V, Anode effective utilization rate: 71.3%, 30-day static capacity loss: 18.7%, 200 mA / cm² polarization voltage drop > 120 mV, severe peeling and corrosion after soaking in 6 mol / L KOH for 7 days.

[0194] Experiment 4: Alloy composition (wt%): Zn 0.90, In 0.11, Sn 0.09, Ga 0.065, La 0.04, Ce 0.02, Zr 0.025; impurities ≤0.05% (Fe ≤0.02, Si ≤0.015), balance is Al with purity ≥99.995%.

[0195] Performance test results:

[0196] Self-corrosion rate: 0.16 mg / (cm²·h), stable discharge potential at 100 mA / cm²: -1.32 V, effective anodic utilization rate: 86.2%, capacity loss after 30 days of static storage: 4.2%, polarization voltage drop at 200 mA / cm²: 70 mV, long-term immersion in 6 mol / L KOH for 7 days: no layer peeling, no corrosion.

[0197] Experiment 5

[0198] Alloy composition (wt%): Zn 1.05, In 0.13, Sn 0.10, Ga 0.075, La 0.045, Ce 0.02, Zr 0.03; impurities ≤0.05% (Fe≤0.02, Si≤0.015), balance is Al with purity ≥99.995%.

[0199] Performance test results:

[0200] Self-corrosion rate: 0.14 mg / (cm²·h), stable discharge potential at 100 mA / cm²: -1.29 V, effective anodic utilization rate: 85.7%, capacity loss after 30 days of static storage: 4%, polarization voltage drop at 200 mA / cm²: 69 mV, long-term immersion in 6 mol / L KOH for 7 days: no layer peeling, no corrosion.

[0201] Experiment Six

[0202] Alloy composition (wt%): Zn 0.75, In 0.095, Sn 0.075, Ga 0.055, La 0.035, Ce 0.025, Zr 0.02; impurities ≤0.05% (Fe≤0.02, Si≤0.015), balance is Al with purity ≥99.995%.

[0203] Performance test results:

[0204] Self-corrosion rate: 0.13 mg / (cm²·h), stable discharge potential at 100 mA / cm²: -1.27 V, effective anodic utilization rate: 86.5%, capacity loss after 30 days of standing at room temperature: 3.8%, polarization voltage drop at 200 mA / cm²: 70 mV, long-term immersion in 6 mol / L KOH for 7 days: no layer peeling, no corrosion.

[0205] The performance comparison is as follows:

[0206] Self-corrosion rate (mg / (cm²·h)) 0.27 0.16 0.14 0.13 Discharge potential (V) of 100 mA / cm² -1.22 -1.32 -1.29 -1.27 Anode utilization rate (%) 71.3 86.2 85.7 86.5 30-day static capacity loss (%) 18.7 4.2 4 3.8 200mA / cm² polarization voltage drop >120mV 70mV 69mV 70mV Soaking in 6 mol / L KOH for 7 days Severe corrosion and large areas of peeling No peeling or corrosion No peeling or corrosion No peeling or corrosion

[0207] As can be seen from the table, electrospinning of the anode material can improve various properties to a certain extent, especially its excellent corrosion resistance in strong alkaline environments. At the same time, the static capacity loss is much smaller than that of currently commercially available anode alloys, and the performance is further improved.

[0208] Based on the disclosure and teachings of the foregoing specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention.

Claims

1. An aluminum-air battery anode alloy material, characterized in that, Its composition by mass percentage is: 0.70–1.10 wt% Zn, 0.09–0.14 wt% In, 0.07–0.11 wt% Sn, 0.05–0.08 wt% Ga, 0.03–0.05 wt% La, 0.015–0.035 wt% Zr, 0.015–0.025 wt% Ce, with unavoidable impurities totaling ≤0.05 wt%, and the balance being aluminum.

2. A method for preparing an aluminum-air battery anode alloy material, characterized in that, The anode alloy material is prepared by setting the raw materials according to the composition ratio of the anode alloy material as described in claim 1. The specific composition ratio is as follows, by mass percentage: 0.70-1.10 wt% Zn, 0.09-0.14 wt% In, 0.07-0.11 wt% Sn, 0.05-0.08 wt% Ga, 0.03-0.05 wt% La, 0.015-0.035 wt% Zr, 0.015-0.025 wt% Ce, with unavoidable impurities ≤0.05 wt%, and the balance being aluminum; The specific preparation steps of the anode alloy material include: The raw materials of the anode alloy are placed in a melting furnace and melted to obtain a melt. The melt is directionally solidified and then homogenized by annealing to obtain an ingot. The ingot is subjected to warm rolling and stress-relief annealing to obtain a coil. Finally, the roll material is die-cut into shape.

3. The method for preparing an aluminum-air battery anode alloy material according to claim 2, characterized in that, After the warm rolling and stress-relief annealing processes are completed, the roll material is subjected to electrospinning treatment, specifically as follows: Surface pretreatment of the roll material; The surface of the roll material is then modified using roll-to-roll electrospinning technology. Finally, nitrogen gas with a purity of ≥99.999% is introduced to protect the electrospun roll material, followed by low-temperature curing.

4. The method for preparing an aluminum-air battery anode alloy material according to claim 3, characterized in that, The electrospinning solution formulation used in the roll-to-roll electrospinning technology is as follows: by mass percentage, 12-15 wt% polyvinylidene fluoride, 3-5 wt% sulfonated polyether ether ketone, 1.5-2.5 wt% γ-Al2O3, 0.5-1.0 wt% boron-nitrogen co-doped carbon nanoparticles; the balance is N,N-dimethylformamide.

5. The method for preparing an aluminum-air battery anode alloy material according to claim 4, characterized in that, The method for preparing the electrospinning solution is as follows: The raw materials are prepared according to the electrospinning solution formula, and the raw materials are placed in a sealed container; The raw materials were stirred at 200 r / min at room temperature for 12 hours. The stirred raw materials were then ultrasonically dispersed for 30 minutes. Finally, the ultrasonically dispersed raw materials are subjected to vacuum degassing for 10 minutes.

6. The method for preparing an aluminum-air battery anode alloy material according to claim 2, characterized in that, The specific steps for melting the component raw materials of the anode alloy material in a melting furnace to obtain a melt are as follows: Al, La, Ce, and Zr raw materials were pretreated to obtain Al-10La, Al-10Ce, and Al-5Zr aluminum-based master alloys and aluminum ingots with oxide scale removed. The Al raw material is loaded into the furnace. After loading, the furnace is evacuated to maintain the pressure inside the furnace at 0.09 to 0.11 Pa, and the pressure is maintained for 10 minutes. After holding the pressure, the furnace is heated to maintain the melting temperature at 730-750℃. After the aluminum ingot is completely melted, keep it at that temperature for 10 minutes, and then degas and remove slag. Add the materials in the following order: Zn→Sn→Ga→In→Al-10La, Al-10Ce→Al-5Zr. Keep the temperature for 5 minutes after each element is added. After all raw materials have been added, argon gas with a purity of ≥99.999% is introduced into the melting furnace for protection, and the materials in the furnace are mechanically stirred at a stirring speed of 30 r / min for 30 to 35 minutes. When the melt temperature stabilizes at 732 to 748℃, it is ready for casting.

7. The method for preparing an aluminum-air battery anode alloy material according to claim 6, characterized in that, The specific pretreatment steps for pretreating Al, La, Ce, and Zr raw materials are as follows: The pretreatment steps for Al raw materials are as follows: the Al raw materials are treated by sandblasting to remove oxide scale, then the aluminum treated by sandblasting to remove oxide scale is ultrasonically cleaned with anhydrous ethanol, and finally the aluminum after ultrasonic cleaning is dried at 120℃ for 1 hour. The pretreatment steps for La, Ce, and Zr raw materials are as follows: aluminum ingots are put into a melting furnace and the temperature is raised to 750-770℃ to melt the aluminum ingots. 0.03-0.05wt% La, 0.015-0.035wt% Zr, and 0.015-0.025wt% Ce are added to the melting furnace and the temperature is raised to 820-880℃. Then, argon gas with a purity ≥99.999% is introduced for protection and mechanical stirring is carried out for 20 minutes. Samples of the melt are taken before the furnace for rapid composition analysis and fine-tuning is carried out according to the analysis results. After obtaining Al-10La, Al-10Ce, and Al-5Zr, they are cast, milled, and crushed for later use.

8. The method for preparing an aluminum-air battery anode alloy material according to claim 2, characterized in that, The directional solidification step is as follows: after the raw materials of each component of the anode alloy material are melted, the melt is poured into the copper mold at a flow rate of 0.35-0.55 kg / s. After the ingot is demolded, it is placed on a ventilated and air-cooled rack, and the cooling rate of the ingot is controlled at 15-20℃ / s by adjusting the wind speed. The homogenization annealing step is as follows: after the melt poured into the copper mold cools to room temperature to obtain an ingot, the ingot is placed in an annealing furnace, nitrogen gas with a purity of ≥99.999% is introduced, the temperature of the annealing furnace is raised to 420-450℃, and held for 6-8 hours.

9. The method for preparing an aluminum-air battery anode alloy material according to claim 2, characterized in that, The low-temperature curing process employs segmented curing, with the specific steps as follows: The first step involves preheating at 80℃ for 30 minutes. The second stage involves curing at a constant temperature of 100℃ for 1.5 hours. The third step involves placing the item in a 60℃ environment and allowing it to cool slowly for 30 minutes. During the segmented curing process, nitrogen gas with a purity of ≥99.999% is introduced throughout the process, and the gas pressure inside the furnace is maintained at 0.01~0.025MPa.

10. The method for preparing an aluminum-air battery anode alloy material according to claim 2, characterized in that, The surface pretreatment step adopts a continuous online cleaning line method.

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