Method for high-value utilization of hydrogen storage alloy ultrafine powder

Abstract

The application provides a high-value utilization method of hydrogen storage alloy superfine powder, and belongs to the field of molten salt electrochemistry. The main problem solved by the application is that hydrogen storage alloy powder, which cannot be continuously coated on the current collector of battery pole piece to make it continuous, makes the dream of low-cost, large-scale and high-value treatment of hydrogen storage alloy superfine powder in the hydrogen storage alloy powder production industry come true. The method comprises four steps of "constructing a molten salt coating plating tank for continuous production of strips", "preparing materials, tank loading and pre-plating", "molten salt coating plating continuous production of coated strips", and "strip post-treatment and related characterization". The effect is that the problem that the hydrogen storage alloy powder production industry has been seeking a low-cost or high-value utilization method for hydrogen storage alloy superfine powder for many years but has not succeeded is solved; a new scheme is provided for the electrolytic hydrogen production negative electrode containing a catalyst strip and solid-state hydrogen storage in the hydrogen energy industry, and a convenient new way is provided for producing a foam nickel strip product containing super-entropy change hydrogen storage alloy.

Description

Technical Field

[0001] This invention relates to a method for the high-value utilization of ultrafine hydrogen storage alloy powder. Specifically, it relates to a method for coating ultrafine hydrogen storage alloy powder onto the negative electrode current collector of a nickel-metal hydride battery using a non-aqueous coating plating process, thereby enabling the high-value utilization of the ultrafine powder. Background Technology

[0002] In the past decade, China's annual production and sales volume of hydrogen storage alloys has been around 90,000 to 110,000 tons. They are almost entirely used as negative electrode active materials in alkaline nickel-metal hydride batteries. Industrially, they are commonly known as "hydrogen storage alloy powder". The product type or form is mainly sold in two forms: "coarse powder" and "fine powder". The particle size of the "coarse powder" is generally around "150 mesh ± 50 mesh", while the so-called "fine powder" is about "250 mesh ± 50 mesh". Because alloy pulverization primarily employs nitrogen-flow circulating pulverization, a certain amount of "fineer powder" (smaller particle size) inevitably arises alongside the production of "coarse powder" and "fine powder," which are "fineer" than the required mesh size for the finished product. If this "fineer powder" exceeds 600 mesh (smaller than 600 mesh) when measured using a Taylor standard sieve, it is called "ultrafine powder." Generally, "ultrafine powder" ranges in mesh size from 600 to 900 mesh. Some companies specify different mesh sizes for their high-end battery products. The standards are even stricter. For example, "fineer powders" with a mesh size distribution between 450 and 900 mesh are considered ultrafine powders. Ultrafine powders are strictly restricted from entering products because when used as the negative electrode active material in alkaline nickel-metal hydride batteries, ultrafine powders can seriously affect battery production and product quality. For example, the suspension of ultrafine powder slurry can cause slurry segregation, leading to a sharp drop in battery consistency. Ultrafine powders can also pulverize during battery cycling, reducing battery life. In short, the presence of ultrafine powders seriously affects battery quality.

[0003] Hydrogen storage alloy powder manufacturers have been working hard to reduce the amount of "ultrafine powder" produced through technological innovation. Currently, the reduction level achieved by each factory is about 1‰ to 5‰ (based on the finished product). Even so, domestic hydrogen storage alloy powder manufacturers still produce tens of tons of this "ultrafine powder" every year. For decades, hydrogen storage alloy powder manufacturers have been searching for low-cost methods to reuse ultrafine hydrogen storage alloy powder. One method involves cooling and pressing the ultrafine powder into blocks, then adding a small amount as an admixture when smelting new hydrogen storage alloys. However, a major problem has been found: the high oxygen content of the ultrafine powder degrades the quality of the smelted new hydrogen storage alloys. Another method involves dissolving the ultrafine powder in acid, turning approximately 60 wt.% nickel and 30 wt.% rare earth elements into a salt solution. Obviously, this method implies various difficulties such as subsequent extraction and separation. For hydrogen storage alloy powder manufacturers, this requires investment in new extraction and separation equipment and technologies, increasing the cost of hydrogen storage alloy products and raising prices. If sold to extraction and separation plants, storage and transportation costs are also not low.

[0004] Researchers working on hydrogen storage alloy powder have been searching for low-cost or high-value utilization methods for ultrafine hydrogen storage alloy powder, but so far they have not found a solution. For example, Japanese researchers have attempted to use water-based coating plating technology to composite nickel plating of hydrogen storage alloy powder on the hydrogen electrode of fuel cells, enabling the high-value utilization of hydrogen storage alloy powder. However, this research has so far remained at the "research" level (Wang Shilu, New Trends in the Application of Composite Electroplating Layers [J], Electroplating & Finishing, 2002, Vol. 24, No. 5, pp. 37-39). Obviously, if AB5 type hydrogen storage alloy is used, the rare earth lanthanum and other active elements in it seem to present insurmountable technical barriers in preventing oxidation in aqueous electroplating. While AB2, AB, or A2B type hydrogen storage alloys do not present insurmountable technical barriers in aqueous coating plating systems, their poor activation and easy poisoning characteristics render the composite plating meaningless. The fundamental problem is that AB5 type hydrogen storage alloy powder currently accounts for more than 96% of all types of hydrogen storage alloy powder. At such a small particle size, the active rare earth elements such as lanthanum are powerless against the oxidation of anolyte gas dissolved in the plating solution by water-based coating plating.

[0005] In aqueous electroplating solutions, particulate matter that cannot dissolve in the solution is added and deposited into the plating layer during the electroplating process. This electroplating method is called coating plating. Other names include occlusion plating, dispersion plating, and composite plating. As the names suggest, it is clear that...

[0006] The term "composite electroplating" is used from the perspective of ordinary aqueous solution electroplating without the addition of particulate matter, in order to distinguish it from ordinary electroplating, such as the common nickel plating process.

[0007] Coating and embedding electroplating are defined from the perspective of coating or embedding particles into the coating layer. "Dispersion electroplating" is defined from the perspective of how to uniformly disperse "particles" in the electroplating solution so that the electroplating can be carried out stably and effectively (Feng Qiuyuan et al., Research on the Mechanism of Composite Electroplating and the Latest Progress [J], Rare Metal Materials and Engineering, 2007, No. 3, pp. 559-564).

[0008] Over the past 100 years, coating has evolved from initially coating the saw teeth of wood saws with diamond (Al2O3) to various industries. Although its main applications are still in heavy industry for cutting and grinding tools, it is now common to see dental drills coated with diamond powder. There are also research reports on the breakthrough of adding molecular sieve microparticles to tin-plating aqueous solutions and plating them onto copper foil as lithium-ion tin anodes to improve the anode capacity of lithium-ion batteries (Fan Xiaoyong et al., Composite Electroplating Preparation and Performance of Sn-SBA15 Anode Material for Lithium-ion Batteries [J], Electrochemistry, 2007, Vol. 1, pp. 25-29).

[0009] In industry, there are often two criteria for determining whether a coating has industrial value or practicality:

[0010] One issue is whether the particles in the suspension plating solution are uniformly dispersed. Because the density difference between the aqueous plating solution and the particle density is too large, the particles will settle due to gravity in the aqueous plating solution. Even with the addition of many thickening plating additives, this gravity settling will still result in uneven dispersion or distribution of particles in the plating solution, ultimately leading to uneven coating and uneven peel strength distribution. The best solution is to use the original "liquid pump circulation method" or a circulation pump to circulate the electroplating solution containing the particle suspension in the trough. The earliest use of this method can be found in the United States Patent and Trademark Office, in patent application number USP2,020,117 published in 1930 entitled "Cutting, grinding, and burnishing tool and the production thereof".

[0011] Those in the molten salt industry know that the density of non-aqueous molten salts or their melts is much greater than that of aqueous solutions, typically approaching twice the density. This significantly reduces the density difference between particles and the melt, naturally creating conditions to reduce "gravitational settling of particles in the electroplating solution." This is one of the reasons why this invention uses non-aqueous molten salts instead of water for coating plating.

[0012] Secondly, does the particle in the suspension plating solution easily acquire a positive charge? Obviously, only when the particles in the plating solution and the metal cations in the solution carry the same positive charge can they easily co-deposit on the cathode in the electroplating tank. In water-based coating plating, the cost of additives added to make the coated particles carry a positive charge is sometimes very high. For example, in nickel or copper plating systems, diamond (Al2O3) is added to manufacture saw blades—the most widely produced type of coated saw blade in industry—often requiring the addition of rubidium (Rb) or thallium (TI) salts. + or TI + Two types of ions adsorb onto the surface of Al2O3 particles, making it easy for diamond particles to co-precipitate with nickel or copper (Wu Yinan, Xu Huiguang, Dispersed Electroplating [J], Electroplating and Environmental Protection, No. 4, 1984, pp. 28-33). However, the price of these two elements, tungsten or thallium, is very high. Although tungsten or thallium ions can be recycled in electroplating, the initial investment is still considerable. More importantly, the toxicity of thallium makes electroplating wastewater "more toxic than toxic," resulting in higher treatment costs.

[0013] Those in the field of molten salt electrochemistry know that, compared to non-aqueous molten salt or molten metal plating solutions, metal particles in many molten salts readily acquire a positive charge. For example, in electrodeposition using chloride molten salt systems, the anolyte (chlorine) is dissolved to varying degrees in the molten salt. When metal particles in a chloride molten salt plating solution encounter chlorine gas or atomic chlorine, the particles are chlorinated. The chlorinated surface of the particles transforms the metal into cations, which, under the control of desorption and diffusion, naturally acquire a positive charge. This differs from the particles in aqueous electroplating solutions where the anolyte is oxidized by oxygen. This is another reason why this invention uses non-aqueous molten salt instead of water for coating plating.

[0014] In addition, non-aqueous molten salt electroplating has two other advantages over aqueous electroplating: active metals such as rare earths, magnesium, and aluminum are difficult to electroplating in aqueous solutions, but this technical obstacle does not exist for electroplating using molten salt as the medium. Another advantage is that aqueous electroplating is performed at room temperature, while molten salt electroplating can be carried out at room temperature, 400°C, 800°C, and other higher temperatures. Increasing the temperature results in a higher degree of alloying between the plated metal and the plated metal substrate, which is more robust. This provides an option for electroplating requiring robust properties. This is one of the original intentions of this invention to choose the KCl+LiCl binary molten salt system with a low eutectic temperature of 352°C (Wu Yaoming, Su Mingzhong, Du Senlin; Research Progress of Molten Salts [J], Chemical Industry Progress, 1995, No. 5, P5-27).

[0015] In summary, a good method for high-value utilization of the ultrafine powder generated during the processing of AB5 type hydrogen storage alloy powder for nickel-metal hydride secondary batteries has not yet been found. AB5 type hydrogen storage alloy powder consistently accounts for over 90 wt.% of the total amount of all types of hydrogen storage alloy powder, indicating a significant market demand for high-value utilization technology for this ultrafine powder. Furthermore, when using traditional aqueous solution coating technology, the rare earth and aluminum active elements in the AB5 type hydrogen storage alloy powder easily lose their activity when used as active materials for hydrogen storage, especially in nickel-metal hydride secondary batteries.

[0016] The Chinese Patent Office recently published an invention patent with publication number CN 113437247 A, application number 202110710391.6 and title "Method for Electrodeposition of Active Material by Molten Salt on Battery Current Collector". From the perspective of process research or pilot-scale testing, this invention patent possesses very high "three-fold" characteristics (indicating high performance, high reliability, and high technological content), and its scientific principles are described in great detail. This provides a foundation for this invention to achieve industrial mass production or industrialization by "standing on the shoulders of giants". As long as some technical deficiencies in industrial mass production or industrialization are overcome, a new invention with a higher level of "three-fold" characteristics can be provided. The technical deficiencies of this invention can be briefly summarized as follows:

[0017] Firstly, this invention adds AB5 type hydrogen storage alloy powder, which is commercially available AB5 type hydrogen storage alloy powder with a particle size of 200 mesh ± 50 mesh, into the electrodeposition tank. This completely ignores the issue of high-value utilization of ultrafine hydrogen storage alloy powder, leading to design flaws. Compared with this invention, its technical defects are twofold, as detailed in Table 1:

[0018] Table 1. Comparison of consumable anode powders, technical defects, and corresponding remedies.

[0019]

[0020]

[0021] Secondly, on the one hand, the electrodeposition tank of the aforementioned invention is cylindrical and made of dense graphite, while the tank of this invention is square and made of nickel profile; on the other hand, the electrodeposition tank of the aforementioned invention uses external heating, while the invention of this application uses internal heating; the relative technical defects of the aforementioned invention in these two aspects and the remedies of the defects by the present invention are summarized in Table 2:

[0022] Table 2. Comparison of differences in tank type, tank material, and heating method, along with analysis of technical defects and remedies.

[0023]

[0024]

[0025] Thirdly, the third obvious defect of the invention CN 113437247 A lies in the lack of technology for improving the stability of molten salt coating plating suspensions: As industry insiders know, for coating plating, whether it is an aqueous solution or a molten salt solution, since it contains solid components, how to ensure that the solid components can be dispersed in the liquid phase for a long time so that the electrolyte forms a stable suspension is the most basic guarantee for the success of the technology. Aqueous solutions can use mud pumps to circulate the coating plating suspension, so that the suspension is stable and continuous; however, due to the limitations of temperature and pump corrosion, it is difficult to use ordinary mud pumps for molten salt coating plating, and only conventional blade mechanical agitation or plunger mechanical agitation can be used (Huang Lingfeng et al., Development Trend of Composite Electroplating Technology and Application [J], Thermal Spraying Technology, 2019, 11(3):1-6); therefore, all technologies that are conducive to the stability of molten salt coating plating suspensions should be explored as much as possible to ensure the stability and continuity of the coating plating suspension, but CN 113437247 Invention A exhibits significant shortcomings and defects in this regard, merely utilizing the bubble force of rising chlorine gas to maintain the stability and continuity of the coating plating suspension; while using the reciprocating vibration and friction of anions and cations at their original equilibrium positions to improve the stability and continuity of the electroplating suspension (Yu Rongjun, Investigation on the Electrolysis Process under Alternating Current [J], Chemical Education, 2016, 37(13): 61-63), or using the principle of spur current to enhance the stability and continuity of the electroplating suspension (Liu Yongsheng et al., Study on the Electrochemical Characteristics of Flowing Liquids [J], Hydraulics and Pneumatics, 2019, (9): 62-64), or introducing the "internal heating" technology, which is not commonly used in the molten salt electrolysis industry and uses alternating current inside the electrodeposition tank, to enhance the stability and continuity of the coating plating suspension.

[0026] The earliest reported case of introducing AC electrodes into DC electrolyzers in China is a patent report published by the Chinese Patent Office more than 20 years ago entitled "A Novel Molten Salt Electrolysis Cell". The patent authorization announcement number is CN2457175Y, and the corresponding patent application number is 00267763.6 or 2000267763.6. This invention uses a molten salt transformer as an AC power source and boldly inserts two AC probes into a cylindrical DC electrolyzer to heat the molten salt electrolyte. It is called "bold" because inserting two AC probes into such a small cylindrical electrolytic cell is something most industry peers would not even dare to imagine what would happen in such a small continuous electrolytic system where AC and DC coexist. As it turns out, it has achieved good results and has been successful. Later, it was explained by domestic molten salt electrolytic rare earth peers as follows: "For the two inserted AC electrodes, the surfaces of the two electrodes alternately attract cations and anions. Only a small number of ions discharge on the electrode surface, while most ions do not have time to move in a directional manner and vibrate back and forth in their original equilibrium positions. The vibration and friction of cations and anions generate heat, thus achieving the purpose of energy-saving heating inside the electrolytic cell, while hardly affecting the original DC electrolysis."

[0027] Obviously, in the process of exploring the stability technology of molten salt coating plating suspension, the invention of CN 113437247 A uses alternating current to make the anions and cations in the plating solution vibrate back and forth at their original equilibrium positions, thereby increasing the entropy value of the plating solution and thus increasing the stability of the molten salt coating plating suspension. However, it does not fully explore the successful technologies of the predecessors, so it is called the third obvious technical defect.

[0028] Furthermore, it is obvious that simply copying the patent CN2457175Y entitled "A Novel Molten Salt Electrolysis Cell" into this invention would introduce new technical defects. This is because the sole purpose of that invention is internal heating, and to achieve this, the bottom of the AC heating probe is made conical to minimize the resistance to tumbling of the electrolyte towards the central axis within the cylindrical electrolytic cell. However, internal heating in this invention is merely an auxiliary purpose; the more advanced objective is to introduce an AC source to further improve the suspension environment near the continuous electrodeposition zone. This requires building upon the invention of CN2457175Y and making highly creative or radical changes to the internal heating probe's shape, placement within the cell, relative electrode spacing between the two probes, axial matching of the probe and the traveling strip along the X, Y, and Z axes, and the probe material, etc. The final result of such highly creative modifications is detailed in the appendix to this invention. Figure 2 This is not redundant.

[0029] The above-mentioned "background technology" is repetitive or redundant. The closest prior art to this invention is the Chinese Patent Office's recently granted patent CN 113437247 B (application number and title are 202110710391.6 and "Method for Electrodeposition of Active Material by Molten Salt on Battery Current Collector"). The biggest technical defect of this patent is that it cannot continuously produce strips, especially the molten salt coated strips urgently needed by the hydrogen energy and battery industries. The invention proposed by the inventor is both a remedy for the defects or deficiencies of all prior art, including the technology of patent No. 202110710391.6, and an improvement of the technology of patent No. 202110710391.6 in terms of its "three properties" (performance, characteristics, and characteristics). Summary of the Invention

[0030] Given the current limitations and deficiencies in the molten salt coating plating technology, particularly regarding the production of catalyst-containing anode strips for hydrogen electrolysis in the hydrogen energy industry and nickel-plated steel strips or foamed nickel strips in the battery industry—namely, the lack of continuous production equipment or dedicated devices for molten salt coating plating, and the absence of corresponding continuous electrodeposition processes—this invention addresses these deficiencies by providing a representative or case-based solution for the high-value utilization of ultrafine hydrogen storage alloy powder through molten salt coating plating technology. It offers a key piece of equipment for continuous molten salt coating plating production in the hydrogen energy industry (catalyst-containing anode strips for hydrogen electrolysis) and the battery industry (nickel-plated steel strips or foamed nickel strips), specifically an electrodeposition tank, and the process technology for continuous electrodeposition using this tank. The invention also aims to expand its application to more industries. In short:

[0031] The purpose of this invention is to provide a method for the high-value production of hydrogen storage alloy ultrafine powder, and in particular, to provide a method that can be easily extended to the field of continuous production of molten salt coating beyond the "use case of hydrogen storage alloy ultrafine powder" of this invention.

[0032] To achieve the objective of this invention, "a method for high-value production of ultrafine hydrogen storage alloy powder," the invention primarily employs the following four-step technical solution:

[0033] The first step is to construct a plating bath for continuous production of molten salt coating of strips; the second step is to prepare materials, load the bath and pre-electroplating; the third step is to continuously produce coated strips using molten salt coating; and the fourth step is to perform strip post-treatment and related characterization.

[0034] in:

[0035] Step 1: Constructing a plating bath for continuous production of strips using molten salt coating:

[0036] The molten salt coating plating tank for continuous production of strips constructed in this invention is a rectangular parallelepiped with an open top. The tank shell is made of nickel plate or nickel-based alloy plate, and the tank shell also serves as a container for the molten salt electrolyte. The tank shell also provides a supporting base for the bottom insulator of the anode and the bottom insulator of the L-shaped AC probe in the plating tank. Another function of the tank shell is to serve as one of the supplementary sources of nickel ions in the molten salt electrolyte in the plating tank.

[0037] This molten salt coating plating tank is equipped with four control rollers that drive the strip forward, two of which are driven rollers partially immersed in the liquid electrolyte. The functions of these partially immersed driven rollers are twofold: firstly, to compress a certain length of the strip below the electrolyte surface; and secondly, to ensure the strip moves continuously along its central axis at a certain speed. Two of the rollers are located above the plating tank. One roller above the tank is the strip-driving guide roller, and its contact portion with the strip is insulated with a ceramic ring, ceramic sheet, or mica sheet. The other roller above the tank is the strip-powered guide roller, its surface in close contact with the strip, and its side rim connected to the negative output terminal of the rectified power supply via brushes. Its function is to support both the continuous movement and continuous power supply of the strip.

[0038] This molten salt coating plating bath contains a strip of deposited negative electrode carrier, which is the negative electrode of the bath. The material of this strip is foamed nickel, nickel-plated steel strip, steel strip, or porous nickel.

[0039] A bottom-mounted anode is installed at the bottom of this molten salt coating plating tank, connected to the positive output of a rectified power supply via a conductive rod. It is made of dense graphite and shaped like a graphite plate. Its main functions are threefold: first, it serves as an essential anode in the electrodeposition tank, paired with the cathode; second, it acts as a solid particle support plate within the coating plating tank, comprising two parts: one part consists of solid particles initially manually added to the graphite plate during electrodeposition, and the second part consists of solid particles that settle to varying degrees from the electrolyte suspension during continuous production in the electrodeposition tank; third... As a chlorination reaction bed and particle activation bed, or as the graphite plate generates highly active atomic chlorine and extremely oxidizing chlorine gas in the chloride molten salt electrodeposition system, the alloy, metal and oxide particles on the graphite plate are chlorinated by chlorine atoms or chlorine gas. The metal cations generated by complete chlorination enter the electrolyte and become the cationic raw materials for electrodeposition. This is why it is called a "chlorination reaction bed". The particles on the surface that are partially chlorinated become positively charged due to their own chlorination and migrate to the cathode site to be deposited under the action of electric field force. This is why it is called a "particle activation bed".

[0040] Two "entropy-increasing, stabilizing, and temperature-adjustable L-shaped probes" are installed in this molten salt coating plating tank, connected to the "live" and "ground" wires of the molten salt transformer output terminals, respectively. Both probes can be made of graphite, metallic nickel, or nickel-based alloys, and can be fabricated from dense graphite plates, metallic nickel plates, or nickel-based alloy plates. As the name suggests, "entropy-increasing" refers to increasing the entropy (disorder) value of the electrolyte existing in suspension during coating plating; "stabilizing" refers to increasing the "suspension" stability of the electrolyte suspension; "temperature-adjusting" refers to adjusting the electrolyte temperature by adjusting the molten salt transformer speed and the linear distance between the two AC probes (equivalent to increasing or decreasing the electrode spacing); and "L-shaped" refers to the probe's shape resembling the letter "L".

[0041] The "consumable anode powder forming material" sprinkled on the upper surface of the anode graphite plate in the molten salt coating plating tank is made from hydrogen storage alloy ultrafine powder and metal powder. It is formed into blocks through isothermal pressing, then crushed into rice-grain-sized particles. These particles are then sieved to obtain particles with an average diameter of 3mm to 5mm. The main function of these rice-grain-sized particles is to absorb chlorine atoms or chlorine gas generated by the anode graphite plate and convert them into the raw materials required for electrolytes and strips. The types of hydrogen storage alloy ultrafine powder include AB5 type hydrogen storage alloy ultrafine powder or magnesium-containing AB3 type hydrogen storage alloy ultrafine powder. The metal powder includes powders of nickel, iron, magnesium, copper, and molybdenum, as well as powder of semi-metallic selenium. During the forming process, the powder is mixed in one group: nickel, iron, magnesium, and copper powders of the hydrogen storage alloy ultrafine powder, and a mixture of molybdenum and selenium powders.

[0042] Four anode support ceramic insulators are installed at the bottom of the molten salt coating plating tank. The insulators are made of electrical insulating ceramic. A thermocouple with a ceramic sleeve for corrosion protection is inserted into the electrolyte suspension in the plating tank. The function of the thermocouple is to monitor the electrolyte temperature in real time and provide parameters for controlling the coating plating process conditions. The ceramic type of the thermocouple anti-corrosion ceramic sleeve is high alumina ceramic, or a high alumina ceramic sleeve in which the alumina content accounts for 60wt.% to 85wt.% of the total weight of the ceramic material.

[0043] An anode conductive connecting rod is installed inside the molten salt coating plating tank. One end of the connecting rod is connected to the positive output terminal of the rectifier power supply, and the other end is connected to the anode plate. Its material is dense graphite.

[0044] The two "entropy-increasing, temperature-stabilizing L-shaped probes" installed in this molten salt coating plating tank are powered by an adjustable molten salt transformer, also known as a "salt bath furnace transformer". When purchasing this molten salt transformer, you should choose a 3-phase 380V AC power input adjustable transformer. The "adjustable" part means that the transformer has an adjustable range button for the output power.

[0045] The power supply for the cathode and anode in this molten salt coating plating tank is a rectified power supply; the top cover of the tank shell includes an openable and closable cover plate. A cross-sectional schematic diagram of the molten salt coating plating tank for continuous strip production constructed according to this invention is shown in the attached diagram. Figure 2 .

[0046] The second step is material preparation, tank loading, and pre-electroplating:

[0047] ① Preparation of electrolyte: The electrolyte formula in the preparation is: 0.4 wt.% Cu2Cl2—1.0 wt.% FeCl2—2 wt.% CeCl3—2.6 wt.% LaCl3—43 wt.% LiCl—51 wt.% KCl or 1.5 wt.% SmCl3—2.0 wt.% MgCl2—2.5 wt.% CeCl3—44 wt.% LiCl—50 wt.% KCl;

[0048] The preparation method of the electrolyte in the above formula is as follows: the salt raw materials used in the electrolyte formula are added to a molten salt mixing furnace at a temperature of 790°C in the following order: anhydrous potassium chloride → anhydrous lithium chloride → anhydrous lanthanum chloride → anhydrous cerium chloride → anhydrous samarium chloride → anhydrous magnesium chloride; the furnace temperature is reduced to 690°C, and then anhydrous ferrous chloride → anhydrous cuprous chloride are added to the furnace and stirred evenly for later use.

[0049] ② Preparation of "Consumable Anode Powder Molding Material": The formula for the "Consumable Anode Powder Molding Material" in the preparation of this invention is as follows: 0.4wt.% Cu-0.6wt.% Fe-1.5wt.% Mg-2.0wt.% Ni-95.5wt.% AB5 type hydrogen storage alloy ultrafine powder or 0.4wt.% Cu-0.6wt.% Fe-2wt.% Mg-2.0wt.% Ni-95.0wt.% magnesium-containing AB3 type hydrogen storage alloy ultrafine powder or 15wt.% Se-85wt.% Mo; the particle size and corresponding purity of the powder raw materials used in this formula are as follows: the particle size of the hydrogen storage alloy ultrafine powder is greater than 600 mesh, or 60... The particle size of the molybdenum powder was determined by sieving through a 0-mesh Taylor standard sieve, with a purity of 99.5 wt.%. Alternatively, the particle size of the molybdenum powder was greater than 800 mesh, or the sieved portion of commercially available FMo-2 type molybdenum powder was determined by sieving through an 800-mesh Taylor standard sieve, with a purity of 99 wt.%. The particle size of the nickel powder was greater than 800 mesh, or the sieved portion of commercially available carbonyl nickel powder was determined by sieving through an 800-mesh Taylor standard sieve, with a purity of 97 wt.%. The particle size of the iron powder was greater than 800 mesh, or the sieved portion of commercially available carbonyl iron powder was determined by sieving through an 800-mesh Taylor standard sieve, with a purity of 99 wt.%. The particle size of the copper, magnesium, and selenium powders was 200 mesh, with a purity of 99.5 wt.%.

[0050] ③ Preparation of the negative electrode carrier material to be deposited – strips: The strips of the negative electrode carrier material to be deposited are made of foamed nickel, nickel-plated steel strips, steel strips, or porous nickel. Their commercially available specifications are as follows: foamed nickel has an areal density of 255 g / m³. 2 ±20g / m 2 The thickness of the nickel-plated steel strip or steel strip is 0.2 mm; the areal density of the porous nickel is 350 g / m³. 2 ±20g / m 2 .

[0051] ④ The loading procedure and sequence are as follows: according to Appendix Figure 2 The schematic diagram of the plating tank cross-section shows the process of first installing the internal and external components and devices, then adding the electroplating material. The process includes opening the top cover of the tank shell, installing four anode support ceramic insulators at the bottom of the tank, then laying an anode graphite plate on top of the insulators, screwing an anode conductive rod into the hole of the anode graphite plate and connecting it to the corresponding wire of the rectifier power supply, fixing four guide wheels driven by strips and connecting the brush on one of the guide wheels to the corresponding wire of the rectifier power supply, fixing the "entropy-increasing, temperature-stabilizing L-shaped probe" and connecting it to the molten salt transformer, fixing the thermocouple, and using a hand ladle to transfer the molten salt liquid from the molten salt mixing furnace into the plating tank and achieving the desired conditions. Figure 2 The molten salt level is 4cm higher than the level of the subsequently added strips. → Particles of "consumable anode powder molding material" are sprinkled onto the upper surface of the anode graphite plate in the tank. → The molten salt transformer is started to heat or keep the temperature constant at 400℃±10℃ through the "entropy-increasing and temperature-stabilizing L-shaped probe". → A special strip hook is used to pass the strip through the two guide rollers in the tank and finally fix the strip completely on the four guide rollers.

[0052] The amount of "consumable anode powder molding material" particles sprinkled onto the upper surface of the anode graphite plate in the tank, by weight percentage, is 1.5% ± 0.5% of the total weight of electrolyte added to the tank; or the "consumable anode powder molding material" particles account for 1.5 wt.% ± 0.5 wt.% of the total weight of electrolyte.

[0053] ⑤ Pre-plating: Using the actual temperature of the electrolyte displayed by the thermocouple in the electrolyte, a temperature range of 400℃±10℃ is set as the target temperature. This target temperature is achieved by adjusting the output power level of the molten salt transformer and the spacing of the "entropy-increasing and temperature-stabilizing L-shaped probe". Within this temperature range, the rectifier power supply is turned on to apply voltage and current to the anode and cathode in the plating tank. The tank voltage Vc and the cathode current density Id are controlled at: Vc=3V±1.2V, Id=0.05A / cm², respectively. 2 ±0.02A / cm 2 Pre-plating for 20 minutes.

[0054] The third step is the continuous production of coated strips using molten salt coating.

[0055] Based on the pre-electroplating, molten salt coating plating is carried out in a continuous production of coated strips in the following ascending sequence:

[0056] ① Anhydrous sodium fluoride was added to the surface of the electrolyte in the aqueduct, with the amount added accounting for 0.15 wt.% ± 0.03 wt.% of the total weight of the electrolyte.

[0057] ② Rotate the rectifier power supply to increase the output voltage and output current until sparks and bubbles are observed on the surface of the electrolyte and hold for 0.5 minutes. During this period, use a ceramic stirring rod to slide and stir along the interface between the inner surface of the tank shell and the electrolyte, or along the four walls of the tank shell, or "one circle".

[0058] ③ Adjust the output voltage and current of the rotary rectifier power supply to the normal voltage and current state for molten salt coating plating, so that the tank voltage Vc and cathode current density Id are controlled at: Vc = 3V ± 1.2V, Id = 0.18A / cm 2 ±0.08A / cm 2 ;

[0059] ④ Start the motor that drives the guide wheel of the connecting strip and control the strip speed to 1.5cm / min ± 0.2cm / min, or the strip speed to be within the range of 1.5cm ± 0.2cm / min; or the strip speed to be controlled at 1.0cm / min ± 0.2cm / min; until the molten salt coating is completed, turn off the power to the motor that drives the guide wheel of the connecting strip.

[0060] Step 4: Strip post-processing and related characterization

[0061] After the molten salt coating is completed, strip post-treatment and related characterization are carried out in the following ascending order of numbers:

[0062] ① Turn off the rectifier power supply and molten salt transformer power supply → Remove the coated strip → Use a special ceramic scoop to take out the liquid electrolyte from the tank into the cold mold → Cool the strip and electrolyte to room temperature;

[0063] ② The strip cooled to room temperature is cleaned with a high-pressure water gun to remove the entrained molten salt → placed in a hot air oven to dry → the pre-plated section of the strip at the front end is cut off so that it can be welded to the front end of a new strip for secondary or multiple uses in the next production → three samples are taken from different parts of the finished strip using a sampling orifice with a diameter of 20 mm.

[0064] ③ Weigh the three samples taken from the finished strip using a four-digit balance. These samples will be used as the basis for subsequent characterization by the "weight gain method". ※ After obtaining the "weight gain method" data, the samples will be further characterized according to the battery or water electrolysis hydrogen production or other application goals.

[0065] The conventional "weight gain method," when applied to the molten salt coated strips of this invention, means: using the uncoated strip as a blank, calculating the absolute and relative weight gain per unit area of ​​the finished molten salt coated strip; obviously, by using the same sampling aperture to sample both the finished strip and the blank strip, the unit area is fixed; the formulas for the absolute and relative weight gain are respectively: Absolute weight gain = weight of the finished molten salt coated strip - weight of the blank strip before molten salt coating; Relative weight gain = absolute weight gain / weight of the blank strip before molten salt coating.

[0066] The high-value utilization of ultrafine hydrogen storage alloy powder, with its strips serving as current collectors for the negative electrode of batteries, is related to factors such as charge / discharge voltage, capacity, and lifespan. This is a commonly used method for characterizing battery material performance in simulated batteries.

[0067] In addition, the electrocatalytic effects of coated strips used for the electrolysis of water to produce hydrogen are usually characterized by comparing them with blank strips to rigorously demonstrate whether they are truly effective in practical applications. Specific characterization methods are not redundant.

[0068] The beneficial effects of this invention are:

[0069] Firstly, it solves the problem that the hydrogen storage alloy powder production industry has been searching for for more than 20 years—a method for the low-cost or high-value utilization of ultrafine hydrogen storage alloy powder—and has opened up a new avenue for the industry to process the "waste" or "byproduct" of ultrafine hydrogen storage alloy powder in a low-cost, large-scale, and high-value manner.

[0070] Secondly, it solves the existing problems in the field of molten salt coating technology, namely the lack of continuous production equipment or special equipment for molten salt coating strips, and the lack of corresponding continuous production electrodeposition technology. It not only provides a complete technology for the continuous and large-scale high-value utilization of hydrogen storage alloy powder for the domestic hydrogen storage alloy powder production industry with an annual output of about 100,000 tons, but also provides new technologies or solutions for catalyst strips in the electrolytic hydrogen production negative electrode (porous nickel or thick foam nickel is also used in alkaline water hydrogen production) in the emerging hydrogen energy industry.

[0071] Thirdly, an unexpected new achievement of this invention is that, in the process of producing ultrafine powder strips of hydrogen storage alloy through molten salt coating, the ultra-entropy change hydrogen storage alloy can be obtained by simply rotating a rectifier power supply knob briefly, as shown in the attached figure. Figure 3 As is well known in the battery industry, ultra-entropy change hydrogen storage alloys are the ideal key material for producing wide-temperature-range batteries for all-weather combat use. In the past, the production of ultra-entropy change hydrogen storage alloys was time-consuming, energy-intensive, and involved complex processes and high technical difficulties.

[0072] This provides a convenient new approach for producing foamed nickel strip products with ultra-entropy change hydrogen storage alloy in the negative electrode current collector of wide-temperature-range batteries. Attached Figure Description

[0073] Figure 1 This is a technical flow chart of the "four-step method" for the high-value utilization of hydrogen storage alloy ultrafine powder of the present invention.

[0074] Figure 2 This is a schematic cross-sectional view of the molten salt coating electroplating tank for the high-value utilization method of hydrogen storage alloy ultrafine powder of the present invention; (Attached) Figure 2 In:

[0075] 1 refers to the tank shell, specifically the outer shell of the molten salt coated electroplating tank. Its shape is a rectangular parallelepiped with an opening at the top. It is made of nickel plate or nickel-based alloy plate, cut and welded together. One function is to hold the molten salt electrolyte within the plating tank. Another function is to serve as the base for the bottom of the anode support insulator and the bottom support insulator base for the L-shaped AC probe within the plating tank. A third function is to serve as one of the sources of nickel ions in the molten salt electrolyte within the plating tank. For these functions, the outer shell of this invention can be considered a consumable molten salt coated electroplating tank. In the plating tank shell, or during continuous production, the part of the plating tank shell in contact with molten salt is corroded by liquid molten salt at about 400°C. One of the corrosion products is nickel ions, which enter the molten salt electrolyte and become one of the sources of replenishment for metallic nickel ions in the electrolyte. Obviously, based on the plating tank shell of the present invention, adding one or two or more layers of nickel plates or nickel alloy plates to the part of the nickel shell in contact with molten salt makes the replacement cycle of this consumable molten salt-coated electroplating tank shell longer. This improvement is obvious.

[0076] 2 is a belt-driven forward guide wheel, and the part of the guide wheel that contacts the belt is insulated with a ceramic ring, ceramic sheet, or mica sheet.

[0077] 3 represents the strip of negative electrode carrier to be deposited, which is the object to be coated with molten salt and is also the negative electrode in the molten salt coating system; in the high-value utilization method of hydrogen storage alloy ultrafine powder of the present invention, the strip is mainly foamed nickel or nickel-plated steel strip or steel strip, while the strip used for coating the electrode of water electrolysis to produce hydrogen is mainly strip-type porous nickel.

[0078] 4 is the anode (positive electrode) supporting the ceramic insulator.

[0079] 5 is a molten salt transformer, also known as a "salt-bath furnace potential transformer". Its input terminal (or high-voltage terminal) is a 3-phase 380V AC input terminal, and the output terminal is connected to two "entropy-increasing and temperature-stabilizing L-shaped probes". When purchasing this molten salt transformer, an adjustable transformer (a transformer with adjustable power output) should be selected. If it is not available on the market, it can be obtained by self-modification according to the patent application number 90219115.2 or application number 1990219115.2 published by the Chinese Patent Office entitled "Fast Uninterrupted Power Shifting Voltage Regulating Power Supply for Salt Bath Furnace".

[0080] 6 is the anode, which is the bottom anode of the molten salt coating. It is connected to the output positive terminal of the rectifier power supply (14) through the conductive rod (11). Its material and shape are dense graphite plates. Its main functions are threefold: First, it serves as an essential anode in the electrodeposition tank, paired with the cathode; second, it acts as a carrier for solid particles within the plating tank, comprising two parts: one part consists of solid particles manually added to the graphite plate during the initial electrodeposition process, and the other part consists of solid particles that settle to varying degrees from the electrolyte suspension during continuous production in the electrodeposition tank; third, it serves as a chlorination reaction bed or particle activation bed, where the graphite plate generates highly active atomic chlorine and extremely oxidizing chlorine gas in the chloride molten salt electrodeposition system. Alloy, metal, and oxide particles on the graphite plate are chlorinated by chlorine atoms or chlorine gas, and the resulting metal cations enter the electrolyte, becoming cationic raw materials for electrodeposition—hence the name "chlorination reaction bed"; while particles partially chlorinated on the surface become positively charged due to their own chlorination and migrate to the cathode sites under the influence of the electric field—hence the name "particle activation bed".

[0081] 7 is a consumable anode powder molding material, which is made by isostatic pressing of hydrogen storage alloy ultrafine powder, metal powder or oxide powder and corresponding metal powder; its main function is to absorb chlorine atoms or chlorine gas generated by the anode graphite plate (6) and convert them into the raw materials required for electrolyte and strip.

[0082] 8 is an entropy-increasing, stabilizing, and temperature-adjustable L-type probe. Two probes are used in the plating bath, connected to the "live" and "ground" wires at the output terminals of the molten salt transformer, respectively. The probe is made of graphite, metallic nickel, or their alloys, and can be manufactured from dense graphite plates, metallic nickel plates, or nickel-based alloy plates. As the name suggests, "entropy-increasing" refers to increasing the entropy (disorder) value of the electrolyte in the immersion plating process, which exists in a suspension state. "Stabilizing" refers to increasing the "suspension" stability of the electrolyte suspension. "Temperature-adjustable" refers to adjusting the electrolyte temperature by adjusting the molten salt transformer speed and the linear distance between the two AC probes (equivalent to increasing or decreasing the electrode spacing). "L-type" refers to the probe's shape resembling the letter "L".

[0083] 9 is the driven guide wheel, which is partially immersed in the liquid electrolyte. There are two driven guide wheels partially immersed in the liquid electrolyte. One of their functions is to compress a strip of a certain length below the electrolyte surface; the other function is to ensure that the strip moves continuously along the central axis at a certain speed.

[0084] 10 represents the electrolyte surface and its spatial relationship with the vertical direction of the “guide wheel (9)”, “probe (8)”, “strip (3)” and “anode plate (6)”.

[0085] 11 is an anode conductive link, one end of which is connected to the positive output terminal of the rectifier power supply, and the other end is connected to the "anode plate (6)". Its material is dense graphite.

[0086] 12 is a temperature measuring thermocouple, whose function is to measure the real-time temperature of the liquid electrolyte, providing important parameters for controlling the coating process.

[0087] 13 is the strip power supply guide wheel, which is the power supply strip guide wheel above the plating tank. Its wheel surface is in close contact with the strip, and its side rim is connected to the negative output terminal of the rectifier power supply through brushes. Its function is to support the continuous movement of the strip and to support the continuous power supply of the strip.

[0088] 14 is a rectifier power supply, whose main function is to rectify the AC mains power into DC mains power, which is used as the electrodeposition power supply for coating plating.

[0089] 15 is the cover plate, which is the cover plate of the molten salt plating tank.

[0090] Figure 3 In the high-value utilization method of hydrogen storage alloy ultrafine powder in Embodiment 1 of the present invention, hydrogen storage alloy ultrafine powder is coated onto nickel foam using a chloride system molten salt and used as the negative electrode current collector of a nickel-metal hydride battery. The voltage-time relationship is represented by the charge-discharge diagram of electrochemical characterization carried out in a simulated battery.

[0091] Appendix Figure 3 Curve 1 in the diagram is the voltage-time curve for charging; while curve 2 is the voltage-time curve for discharging. From the characteristics of curve 2 (discharging curve), it can be seen that the starting voltage at the beginning of discharge is much higher than 1.2V. Figure 3 The overall characteristics of curve 2 conform to the discharge curve characteristics of "hyper-entropy change hydrogen storage alloy". Furthermore, it is consistent with the title "AB" published by the Chinese Patent Office on May 2, 2012. 4.7 A comparison is made with the discharge characteristics of the super-entropy change alloy in the patent for "Super-entropy Change Method of Non-Stoichiometric Hydrogen Storage Alloy" (application number and publication number of the patent are "201110109306.7" and "102437317B" respectively), that is, with the appendix in the specification of patent number 102437317B. Figure 4 Comparing with Figure 5, the results show a very high degree of agreement, demonstrating that the new process of this invention can simultaneously obtain ultra-entropy variable hydrogen storage alloys. It is easy to understand that by simply rotating the rectifier power supply output current knob approximately every hour during the continuous coating process of this invention, increasing the output current, and simultaneously raising the tank voltage, potassium and lithium, the solvent elements in the electrolyte, are forced to co-deposit on the cathode of the ultrafine powder coated with the hydrogen storage alloy. Potassium and lithium metals are more or less incorporated into the ultrafine powder particles of the coated hydrogen storage alloy. This brief and easy action is shorter and less energy-intensive than the previous method of lithiumization at around 900°C for 4 to 5 hours to produce ultra-entropy variable hydrogen storage alloys, significantly reducing the production cost of ultra-entropy variable hydrogen storage alloys.

[0092] Figure 4 This is an example of the high-value utilization method of hydrogen storage alloy ultrafine powder in Embodiment 2 of the present invention. Hydrogen storage alloy ultrafine powder is coated onto nickel-plated steel strip using a chloride system molten salt. The particle coating effect is shown under a stereomicroscope. Detailed Implementation

[0093] The present invention will be further described below with reference to specific embodiments; in order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention achieves the purpose of enabling those skilled in the art to better understand the technical solution of the present invention through the detailed implementation method and corresponding precautions or principles of Embodiment 1.

[0094] Example 1

[0095] Nickel foam is used as a strip coated with molten salt in the aqueduct. Ultrafine powder generated from the industrial production of AB5 hydrogen storage alloy is used as a high-value utilization target for this ultrafine powder. In a chloride molten salt suspension system, molten salt coating technology is used to obtain strips in which the negative electrode current collector of a nickel-metal hydride rechargeable battery is coated with AB5 hydrogen storage alloy ultrafine powder, allowing for continuous production. The steps are as follows: Figure 1 As shown,

[0096] Step 1: Constructing a molten salt coating plating bath for continuous production of strips:

[0097] ① The molten salt coating plating tank for continuous production of strips is a rectangular parallelepiped with an opening at the top; the tank shell 1 is made of nickel plate and serves as a container for the molten salt electrolyte; the tank shell 1 also provides a supporting base for the bottom insulator of the anode and the bottom insulator of the L-shaped AC probe in the plating tank; another function of the tank shell is as one of the sources of replenishment for nickel ions in the molten salt electrolyte in the plating tank.

[0098] The principle behind using a nickel plate tank shell as one of the "replenishment sources of metallic nickel ions in the molten salt electrolyte of the plating tank" is as follows: the electrolyte for this coating plating requires nickel ions. As is well known in the industry, one of the methods for preparing anhydrous nickel chloride is to react metallic nickel with chlorine gas. In the continuous production of chloride system coating plating, the anode gas is chlorine gas, which dissolves into the electrolyte. The part of the plating tank shell that comes into contact with the molten salt comes into contact with active chlorine gas, which easily reacts at around 400°C to generate nickel chloride. This reduces the pressure of byproduct chlorine gas on the final treatment of the plating tank during the electrodeposition process, and is also cheaper than purchasing anhydrous nickel chloride and adding it to the electrolyte of the plating tank. This design of obtaining anhydrous nickel chloride by utilizing the in-situ reaction of byproduct chlorine gas achieves the effect of "killing two birds with one stone".

[0099] ② This molten salt coating plating tank is equipped with four control guide wheels to drive the strip forward, two of which are driven guide wheels 9 partially immersed in the liquid electrolyte. One function of these partially immersed driven guide wheels is to compress a certain length of the strip below the electrolyte surface; the other is to allow the strip to move continuously at a certain speed along its central axis. Two of the guide wheels are located above the aqueduct. One guide wheel above the aqueduct is the strip-driving guide wheel 2, and the part of this guide wheel in contact with the strip is insulated with a ceramic ring, ceramic sheet, or mica sheet. The other guide wheel above the aqueduct is the strip-supplying guide wheel 13, whose wheel surface is in close contact with the strip, and whose side rim is connected to the negative output terminal of the rectifier power supply 14 via a brush. Its function is to support the continuous movement of the strip and also to support the continuous supply of electricity to the strip.

[0100] ③A strip 3 of negative electrode carrier deposited in the molten salt coating plating tank. This strip is the negative electrode of the plating tank and its material is nickel foam.

[0101] ④ A bottom-mounted anode 46 is installed at the bottom of the molten salt coating plating tank, which is connected to the positive output of the rectified power supply via a conductive rod; its material is dense graphite, and its shape is a graphite plate; its main functions are threefold: firstly, it serves as an essential anode in the electrodeposition tank, paired with the cathode; secondly, it serves as a solid particle support plate in the coating plating tank, the solid particles comprising two parts: one part being the solid particles manually added to the graphite plate during the initial electrodeposition process, and the second part being the solid particles that settle to varying degrees from the suspended electrolyte during continuous production in the electrodeposition tank; Third, as a chlorination reaction bed and a particle activation bed, or in the case of the graphite plate generating highly active atomic chlorine and extremely oxidizing chlorine gas in the chloride molten salt electrodeposition system, the alloy, metal and oxide particles on the graphite plate are chlorinated by chlorine atoms or chlorine gas. The metal cations generated by complete chlorination enter the electrolyte and become the cationic raw materials for electrodeposition. This is the reason why it is called a "chlorination reaction bed". The particles on the surface that are partially chlorinated are positively charged due to their own chlorination and migrate to the cathode site to be deposited under the action of electric field force. This is the reason why it is called a "particle activation bed".

[0102] ⑤ Two "entropy-increasing, stabilizing, and temperature-adjustable L-shaped probes 8" are installed in this molten salt coating plating tank, connected to the "live" and "ground" wires of the output terminals of the molten salt transformer 5, respectively. The two probes are made of graphite, which can be processed from dense graphite plates. As the name suggests, "entropy-increasing, stabilizing, and temperature-adjustable L-shaped probes" refer to increasing the entropy value (disorder value) of the electrolyte existing in the suspension form during coating plating, "stabilizing" refers to increasing the "suspension" stability of the electrolyte suspension, and "temperature-adjusting" refers to adjusting the electrolyte temperature by adjusting the range of the molten salt transformer and the linear distance between the two AC probes (equivalent to increasing or decreasing the electrode spacing); and "L-shaped" refers to the probe shape resembling the English letter "L".

[0103] ⑥ The "consumable anode powder forming material 7" sprinkled on the upper surface of the anode graphite plate in the molten salt coating plating tank is made of hydrogen storage alloy ultrafine powder and metal powder as raw materials. It is pressed into blocks by isostatic pressing, then crushed into rice-grain-sized particles. These particles are then sieved to obtain particles with an average particle size of 3mm to 5mm. The main function of these rice-grain-sized particles is to absorb chlorine atoms or chlorine gas generated by the anode graphite plate and convert them into the raw materials required for electrolytes and strips.

[0104] ⑦ Four anode support ceramic insulators 4 are installed at the bottom of the molten salt coating plating tank; the material of the insulator is electrical insulating ceramic; a thermocouple with a ceramic sleeve for corrosion protection is inserted in the electrolyte suspension of the plating tank. The function of the thermocouple is to monitor the electrolyte temperature in real time and provide parameters for controlling the coating plating process conditions. The ceramic type of the thermocouple anti-corrosion ceramic sleeve is high alumina ceramic, or a high alumina ceramic sleeve in which the alumina content accounts for 60wt.% to 85wt.% of the total weight of the ceramic material.

[0105] ⑧ An anode conductive connecting rod 11 is installed inside the molten salt coating plating tank. One end of the "connecting rod" is connected to the positive output terminal of the rectifier power supply, and the other end is connected to the anode plate. Its material is dense graphite.

[0106] ⑨ The two “entropy-increasing, temperature-stabilizing L-shaped probes” installed in this molten salt coating plating tank are powered by an adjustable molten salt transformer 5. The molten salt transformer is also called a “salt bath furnace transformer”. When purchasing this molten salt transformer, you should choose an adjustable transformer with a 3-phase 380V AC power input terminal. The “adjustable” part means that the transformer has an adjustable range button for the output power.

[0107] ⑩ The power supply for the cathode and anode in this molten salt coating plating tank is a rectified power supply 14; the top cover of the tank shell includes an openable and closable cover plate 15. A cross-sectional schematic diagram of the molten salt coating plating tank for continuous strip production constructed according to this invention is shown in the appendix. Figure 2 .

[0108] The second step is material preparation, tank loading, and pre-electroplating:

[0109] ① Preparation of electrolyte: The electrolyte formula in the preparation is: 0.4wt.% Cu2Cl2—1.0wt.% FeCl2—2wt.% CeCl3—2.6wt.% LaCl3—43wt.% LiCl—51wt.% KCl.

[0110] The preparation method of the electrolyte in the above formula is as follows: the salt raw materials used in the electrolyte formula are added to a molten salt mixing furnace at a temperature of 790°C in the following order: anhydrous potassium chloride → anhydrous lithium chloride → anhydrous lanthanum chloride → anhydrous cerium chloride; the furnace temperature is reduced to 690°C, and then anhydrous ferrous chloride → anhydrous cuprous chloride are added to the furnace and stirred evenly for later use.

[0111] ②Preparation of “Consumable Anode Powder Molding Material”: The formula of the “Consumable Anode Powder Molding Material” in the preparation of the present invention is: 0.4wt.%Cu-0.6wt.%Fe–1.5wt.%Mg-2.0wt.%Ni–95.5wt.%AB5 type hydrogen storage alloy ultrafine powder. The particle size and corresponding purity of the powder raw materials used in this formula are as follows: the particle size of the hydrogen storage alloy ultrafine powder is greater than 600 mesh, or the sieved portion is obtained by sieving with a 600-mesh Taylor standard sieve, with a purity of 99.5 wt.%; the particle size of the nickel powder is greater than 800 mesh, or the sieved portion of commercially available carbonyl nickel powder is obtained by sieving with an 800-mesh Taylor standard sieve, with a purity of 97 wt.%; the particle size of the iron powder is greater than 800 mesh, or the sieved portion of commercially available carbonyl iron powder is obtained by sieving with an 800-mesh Taylor standard sieve, with a purity of 99 wt.%; the particle size of both copper powder and magnesium powder is 200 mesh, and the purity of both magnesium powders is 99.5 wt.%.

[0112] ③ Preparation of the negative electrode carrier material to be deposited – strips: The strips of negative electrode carrier material to be deposited are made of nickel foam, and the areal density of the nickel foam is 255 g / m³. 2 ±20g / m 2 .

[0113] ④ The loading procedure and sequence are as follows: according to Appendix Figure 2 The schematic diagram of the plating tank cross-section shows the process of first installing the internal and external components and devices, then loading the electroplating material. Open the top cover plate 15 of the tank shell. ※ Install four anode support ceramic insulators 4 at the bottom of the tank. ※ Next, lay the anode 6 graphite plate on these insulators. ※ Screw the anode conductive rod onto the hole in the anode graphite plate and connect it to the corresponding wiring between it and the rectifier power supply. ※ Fix the four guide wheels that drive the strip forward and connect the corresponding wiring between the brush on one of the guide wheels and the rectifier power supply. ※ Fix the "entropy-increasing, temperature-stabilizing, and temperature-regulating L-shaped probe 8" and connect it to the molten salt transformer 5. ※ Fix the temperature-measuring thermocouple 12. → Use a hand ladle to transfer the molten salt liquid from the molten salt mixing furnace into the plating tank and bring it to the desired consistency as shown in the attached diagram. Figure 2 The molten salt level is 4cm higher than the level of the subsequently added strip. → Sprinkle "consumable anode powder molding material 7" particles onto the upper surface of the anode graphite plate in the tank. → Start the molten salt transformer 5 to heat or keep the molten salt electrolyte at a constant temperature of 400℃±10℃ through the "entropy-increasing and temperature-stabilizing L-shaped probe 8". → Use a special strip hook to pass the strip through the two guide rollers in the tank and finally fix the strip completely on the four guide rollers.

[0114] The amount of "consumable anode powder molding material 7" particles sprinkled on the upper surface of the graphite plate of anode 6 in the tank, according to the weight percentage, is 1.5% ± 0.5% of the total weight of electrolyte added to the tank; or the "consumable anode powder molding material" particles account for 1.5 wt.% ± 0.5 wt.% of the total weight of electrolyte.

[0115] ⑤ Pre-plating: Using the actual temperature of the electrolyte displayed by thermocouple 12 in the electrolyte, a temperature range of 400℃±10℃ is set as the target temperature. This target temperature is achieved by adjusting the output power level of the molten salt transformer and the spacing of the "entropy-increasing and temperature-stabilizing L-shaped probe". Within this temperature range, the rectifier power supply is turned on to apply voltage and current to the anode and cathode in the plating tank. The tank voltage Vc and the cathode current density Id are controlled at: Vc=3V±1.2V, Id=0.05A / cm², respectively. 2 ±0.02A / cm 2 Pre-plating for 20 minutes.

[0116] It is worth noting that the definition of cathode current density is the current intensity carried per unit area of ​​the cathode. For nickel foam strips as the cathode, the pores within the nickel foam form a conductive surface with a spatial structure. Furthermore, the irregular spatial conductive surface of these pores is difficult to measure. Therefore, the area calculation for the cathode current density in this embodiment is simply the area obtained by multiplying the length and width of the nickel foam surface, without adding the area of ​​the irregular spatial conductive surface within the pores. Consequently, the objective and true cathode current density in this embodiment is far less than Id = 0.05 A / cm². 2 Or perhaps it's the actual cathode current density. Because the area inside the holes wasn't factored in, the actual cathode area is much larger than the simply calculated conductive area, resulting in the actual cathode current density being much smaller than the cathode current density shown on paper. However, this doesn't affect the research and experimental records of the process. Whenever encountering strips like nickel foam, this "apparent cathode current density" parameter can be used.

[0117] The third step is the continuous production of coated strips using molten salt coating.

[0118] Based on the pre-electroplating, molten salt coating plating is carried out in a continuous production of coated strips in the following ascending sequence:

[0119] ① Anhydrous sodium fluoride was added to the surface of the electrolyte in the aqueduct, and the amount added accounted for 0.15 wt.% ± 0.03 wt.% of the total weight of the electrolyte.

[0120] The design principle for adding a few parts per thousand of anhydrous sodium fluoride to the electrolyte is as follows: Sodium fluoride is a commonly used slag remover in molten salt electrolysis. It is typically added in molten salt electrolysis at a percentage, or a percentage of the total electrolyte weight, which can also be simply referred to as "10%". -2 "Quantity-level", this sodium fluoride can eliminate "carbon slag" (carbides), "oxygen slag" (oxides), and "sulfur slag" (nodules) during the electrolysis process; in this embodiment, it belongs to molten salt coating plating, the current density of electroplating is much lower than that of electrolysis, but the time consumption is much higher than that of electrolysis, providing sufficient time for slag removal. Therefore, adding "10 -3Adding anhydrous sodium fluoride in the "volume" or even "a few parts per thousand" is ideal, because too much fluoride ion left in the electrolyte deviates from the purpose of "green chemistry". In addition, too much fluoride ion is not conducive to the control of solid particles in the suspension.

[0121] ② Rotate the rectifier power supply to increase the output voltage and output current until sparks and bubbles are observed on the surface of the electrolyte and hold for 0.5 minutes. During this period, use a ceramic stirring rod to slide along the interface between the inner surface of the tank shell and the electrolyte and stir for one round, or one round along the four walls of the tank shell, or "one circle".

[0122] The design principle behind this observation method, which involves "observing sparks and bubbles appearing on the electrolyte surface and maintaining this state for 0.5 minutes," is as follows:

[0123] The appearance of sparks on the electrolyte surface is due to the rapid increase in current density and cell voltage. Potassium and lithium, the solvent elements in the electrolyte, co-deposit on the cathode. Because potassium and lithium have low metal density, they float to the electrolyte surface and ignite upon contact with oxygen in the air, producing sparks. Similarly, chlorine deposited on the anode accumulates suddenly and floats to the electrolyte surface, generating bubbles. Clearly, the rising chlorine gas inevitably impacts the "consumable anode powder molding material" particles on the anode graphite plate surface. The technological goal of obtaining a suspension is achieved through this "gas impact." However, this impact must be brief; otherwise, it will affect the cathode efficiency and excessively consume the solvent components in the electrolyte.

[0124] Furthermore, utilizing this brief impact principle, the hydrogen storage alloy coated on the strip can also be used to obtain a "hyper-entropy hydrogen storage alloy" when it serves as the negative electrode active material in a nickel-hydrogen battery. For the definition and preparation principle of the so-called "hyper-entropy hydrogen storage alloy," please refer to the patent titled "AB" published by the Chinese Patent Office on May 2, 2012. 4.7 The patent for "Ultra-entropy Change Method for Non-Stoichiometric Hydrogen Storage Alloys" has application number "201110109306.7" and publication number "102437317B" respectively. The appendix to this invention... Figure 3 The discharge curve characteristics are similar to those of the appendix to the authorized patent No. "201110109306.7". Figure 4 The discharge characteristics of the super-entropy variable alloy are consistent with those in Figure 5, or the starting voltage at the beginning of the discharge is much higher than 1.2V, thus providing empirical evidence for the above statement that "super-entropy variable hydrogen storage alloys are obtained by utilizing this short-term impact principle".

[0125] ③ Adjust the output voltage and current of the rotary rectifier power supply to the normal voltage and current state for molten salt coating plating, so that the tank voltage Vc and cathode current density Id are controlled at: Vc = 3V ± 1.2V, Id = 0.18A / cm 2 ±0.08A / cm 2 .

[0126] ④ Start the motor that drives the guide wheel of the connecting strip and control the strip speed to be 1.5cm / min ± 0.2cm / min, or the strip speed per minute to be within the range of 1.5cm ± 0.2cm; until the molten salt coating is completed, turn off the power to the motor that drives the guide wheel of the connecting strip.

[0127] Step 4: Strip post-processing and related characterization

[0128] After the molten salt coating is completed, strip post-treatment and related characterization are carried out in the following ascending order of numbers:

[0129] ① Turn off the rectifier power supply and molten salt transformer power supply → Remove the coated strip → Use a special ceramic scoop to take out the liquid electrolyte from the tank into the cold mold → Cool the strip and electrolyte to room temperature.

[0130] The precautions for "using a special porcelain ladle to remove liquid electrolyte from the tank into a cold grinding mold" are as follows: the cold grinding mold must be heated and dried on an electric furnace before use, and the operator must wear at least a transparent mask while operating it; otherwise, the liquid molten salt may explode upon contact with water, causing unnecessary injury.

[0131] ② The strip cooled to room temperature is cleaned with a high-pressure water gun to remove the entrained molten salt → placed in a hot air oven to dry → the pre-plated section of the strip at the front end is cut off so that it can be welded to the front end of a new strip for secondary or multiple uses in the next production → three samples are taken from different parts of the finished strip using a sampling orifice with a diameter of 20 mm.

[0132] ③ Use a four-digit balance to accurately weigh the three samples taken from the finished strip, which will be used as the basis for subsequent characterization by the "weight gain method" → obtain the sample after obtaining the "weight gain method" data.

[0133] The conventional "weight gain method," when applied to the molten salt coated strips of this invention, means: using the uncoated strip as a blank, calculating the absolute and relative weight gain per unit area of ​​the finished molten salt coated strip; obviously, by using the same sampling aperture to sample both the finished strip and the blank strip, the unit area is fixed; the formulas for the absolute and relative weight gain are respectively: Absolute weight gain = weight of the finished molten salt coated strip - weight of the blank strip before molten salt coating; Relative weight gain = absolute weight gain / weight of the blank strip before molten salt coating.

[0134] In this embodiment, the relative weight gain of the nickel foam coated with this molten salt is 2.1 wt.%.

[0135] The high-value utilization of ultrafine hydrogen storage alloy powder as a current collector for battery negative electrodes is related to factors such as charge / discharge voltage, capacity, and lifespan. This is a commonly used method for characterizing battery material performance in simulated batteries. The specific characterization method used is the method described in paragraphs

[0112] to

[0113] of the specification of the recently granted Chinese Patent No. CN 113437247 B (application number and title are 202110710391.6 and "Method for Electrodeposition of Active Material by Molten Salt on Battery Current Collector").

[0136] Characterized using the same method described in paragraphs

[0112] to

[0113] , the electrochemical gravimetric capacity of the nickel foam coated with the battery negative electrode active material by this molten salt coating is 252 mAh / g.

[0137] Example 2

[0138] The difference from Example 1 is:

[0139] Firstly, replace "The material of the tank shell constructed in step ① is a nickel plate..." in Example 1 with "The material of the tank shell is a nickel-based alloy plate". The model of the nickel-based alloy plate is C276 (UNS N10276).

[0140] Secondly, the electrolyte formula in "Step 2 ① Preparation of electrolyte: The electrolyte formula in the preparation of materials is..." in Example 1 is replaced with a new formula: 0.4wt.% Cu2Cl2—1.0wt.% FeCl2—2wt.% MgCl2—2.6wt.% LaCl3—43wt.% LiCl—51wt.% KCl. This formula lacks anhydrous cerium chloride compared to the corresponding formula in Example 1; this omission does not change the order of feeding materials in the original molten salt mixing furnace.

[0141] Thirdly, the formula in "Step 2, ②, for preparing [consumable anode powder molding material] is..." in Example 1 is replaced with a new formula of "0.4wt.% Cu-0.6wt.% Fe-2wt.% Mg-2.0wt.% Ni-95.0wt.% magnesium-containing AB3 type hydrogen storage alloy ultrafine powder".

[0142] Fourthly, replace “Step 2, ③, prepare the negative electrode carrier material to be deposited – strip, ... is foamed nickel…” in Example 1 with nickel-plated steel strip, the thickness of which is 0.2mm.

[0143] Fifthly, unlike Example 1, the relative weight gain of the nickel-plated steel strip in this example after being coated with this molten salt is 1.85 wt.%.

[0144] Sixth: Unlike Example 1, the electrochemical weight-to-weight capacity of the nickel-plated steel strip coated with the battery negative electrode active material by this molten salt is 207 mAh / g.

[0145] The rest is the same as in Example 1. Figure 4 This is an example of the high-value utilization method of hydrogen storage alloy ultrafine powder in Embodiment 2 of the present invention. Hydrogen storage alloy ultrafine powder is coated onto nickel-plated steel strip using a chloride system molten salt. The particle coating effect is shown under a stereomicroscope.

[0146] Example 3

[0147] The difference from Example 1 is:

[0148] Firstly, in Example 1, the material of the two probes in step ⑤, "the two probes are made of graphite", is replaced with the material of the two "entropy-increasing, temperature-stabilizing L-shaped probes", which are made of nickel-based alloy, specifically model C276.

[0149] Secondly, the formula in "Step 2, the preparation of [consumable anode powder molding material] is..." in Example 1 is replaced with a new formula of "0.4wt.% Cu-0.6wt.% Fe-1.0wt.% Mg-2.0wt.% Ni-96wt.% AB5 type hydrogen storage alloy ultrafine powder".

[0150] Thirdly, replace “Step 2 ③ in Example 1 with the prepared negative electrode carrier material to be deposited – strip, ... is foamed nickel…” with a steel strip with a thickness of 0.2 mm.

[0151] Fourthly, unlike Example 1, the relative weight gain of the steel strip in this example after being coated with this molten salt is 1.47 wt.%.

[0152] Fifthly, unlike Example 1, the electrochemical weight-to-weight capacity of the nickel-plated steel strip coated with the negative electrode active material of the battery through this molten salt coating is 196 mAh / g.

[0153] The rest is the same as in Example 1.

[0154] Example 4

[0155] The difference from Example 1 is:

[0156] Firstly, replace the material of the two probes in step ⑤ of Example 1 with pure nickel as the material of the two "entropy-increasing, temperature-stabilizing L-shaped probes".

[0157] Secondly, the electrolyte formula in "Step 2 ① Preparation of electrolyte: The electrolyte formula in the preparation of materials is..." in Example 1 is replaced with a new formula of 1.5wt.% SmCl3—2.0wt.% MgCl2—2.5wt.% CeCl3—44wt.% LiCl—50wt.% KCl. The preparation method of the electrolyte formula is as follows: the salt raw materials used in the electrolyte formula are added to a molten salt mixing furnace at a temperature of 790℃ in the following order: anhydrous potassium chloride → anhydrous lithium chloride → anhydrous lanthanum chloride → anhydrous cerium chloride → anhydrous samarium chloride → anhydrous magnesium chloride.

[0158] Thirdly: Replace the formulation in "Step 2, ②, for preparing [consumable anode powder molding material] as..." in Example 1 with a new formulation of "15 wt.% Se – 85 wt.% Mo". In the new formulation, the molybdenum powder has a particle size greater than 800 mesh, or the commercially available FMo-2 type molybdenum powder is sieved using an 800-mesh Taylor standard sieve, and the sieved portion is taken, with a molybdenum powder purity of 99 wt.%. The selenium powder has a particle size of 200 mesh and a purity of 99.5 wt.%.

[0159] Fourthly: Replace "Step 2, ③, preparing the negative electrode carrier material to be deposited—strips, ... is foamed nickel..." in Example 1 with porous nickel. The commercially available specifications of this porous nickel are: its areal density is 350 g / m³. 2 ±20g / m 2 .

[0160] Fifth: Replace “Step 3 ④ Start the motor of the connecting strip drive guide wheel and control the strip forward speed 1.5cm / min±0.2cm / min……” in Example 1 with “The strip forward speed is controlled at 1.0cm / min±0.2cm / min”.

[0161] Sixth: Unlike Example 1, the relative weight gain of the porous nickel strip in this example after being coated with this molten salt is 0.11 wt.%.

[0162] Seventh: Unlike Example 1, porous nickel is used as a strip coated with molten salt in the trough. In the chloride molten salt suspension system, the scientific goal of the molten salt coating technology is to obtain a strip that can be continuously produced by coating the hydrogen production electrode of the water electrolysis industry with selenium and molybdenum hydrogen production catalyst activation particles. Therefore, it is not necessary to perform the relevant characterization as the strip as the negative electrode current collector of the battery in the high-value utilization of ultrafine powder of hydrogen storage alloy.

[0163] The rest is the same as in Example 1.

[0164] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for high value addition of hydrogen storage alloy ultrafine powder, characterized by: It includes the following four steps: The first step is to construct a molten salt coating plating bath for continuous production of strips; The second step is to prepare materials, fill the bath and pre-plating: ① Electrolyte preparation: The electrolyte formula in the preparation is: 0.4 wt.% Cu2Cl2, 1.0 wt.% FeCl2, 2 wt.% CeCl3, 2.6 wt.% LaCl3, 43 wt.% LiCl, and 51 wt.% KCl or 1.5 wt.% SmCl 3、 2.0 wt.% MgCl2, 2.5 wt.% CeCl3, 44 wt.% LiCl and 50 wt.% KCl; ②The formula of the consumable anode powder forming material (7) in the preparation of materials is: 0.4wt.% Cu, 0.6wt.% Fe, 1.5wt.% Mg, 2.0wt.% Ni and 95.5wt.% AB5 type hydrogen storage alloy ultrafine powder or 0.4wt.% Cu, 0.6wt.% Fe, 2wt.% Mg, 2.0wt.% Ni and 95.0wt.% magnesium-containing AB3 type hydrogen storage alloy ultrafine powder or 15wt.% Se and 85wt.% Mo; ③Prepare the deposited negative carrier material - strip: the prepared deposited negative carrier material strip (3) is made of nickel-plated steel strip, steel strip or porous nickel; ④Pre-plating; The third step is to carry out molten salt coating plating for continuous production of coated strips On the basis of pre-plating, carry out molten salt coating plating for continuous production of coated strips in the following order: ①Put anhydrous sodium fluoride into the surface of the electrolyte in the plating bath, and the amount of the anhydrous sodium fluoride accounts for 0.15wt.%±0.03wt.% of the total weight of the electrolyte; ②Increase the output voltage and current of the rotating rectifier power supply until sparks and bubbles are observed on the surface of the electrolyte for 0.5 minutes, during which time the porcelain stirrer is slid along the interface between the inner surface of the tank shell and the electrolyte and stirred for one round or one circle of the four walls of the tank shell; ③Rotating the rectifier power supply to reduce the output voltage and current to the normal molten salt coating plating voltage and current state, so that the cell voltage Vc and the cathode current density Id are controlled at: Vc = 3V±1.2V, Id = 0.18 A / cm 2 ±0.08 A / cm 2 ; ④Start the motor connected to the strip driving front guide wheel, control the strip forward speed at 1.5 cm / min±0.2 cm / min; or the strip forward speed per minute is within the range of 1.5 cm±0.2 cm, or the strip forward speed is controlled at 1.0 cm / min±0.2 cm / min; until the molten salt coating plating is completed and the power supply connected to the strip driving front guide wheel is turned off; The fourth step is strip post-processing and related characterization; The particle size of the hydrogen storage alloy ultrafine powder is less than 600 mesh.

2. The method of claim 1, wherein the hydrogen storage alloy ultrafine powder is characterized in that: The material of the L-shaped probe (8) can be selected from graphite or nickel or nickel-based alloy.

3. The method of claim 1, wherein the hydrogen storage alloy ultrafine powder is characterized in that: The consumable anode powder forming material (7) is composed of hydrogen storage alloy ultrafine powder and metal powder, and the types of hydrogen storage alloy ultrafine powder include AB5 type hydrogen storage alloy ultrafine powder or magnesium-containing AB3 type hydrogen storage alloy ultrafine powder, and the metal powder includes nickel, magnesium, iron, copper and molybdenum powder and semi-metallic selenium powder; the forming process of the forming material is: mixing the hydrogen storage alloy ultrafine powder with nickel powder, magnesium powder, iron powder and copper powder uniformly or mixing molybdenum powder with selenium powder uniformly, cold isostatic pressing into blocks, then knocking into rice-sized particles, and then sieving to obtain particles with an average particle size of 3mm to 5mm; the function of the forming material is to absorb the chlorine atoms or chlorine gas generated by the anode graphite plate and convert them into raw materials required by the electrolyte and the strip.

4. The method of claim 1, wherein the hydrogen storage alloy ultrafine powder is characterized in that: The material of the four anode support porcelain insulators (4) installed at the bottom of the tank is electrical insulating porcelain.

5. The method of claim 1, wherein the method is characterized by: The anode conductive connecting rod (11) is made of dense graphite, one end of which is connected with the positive output end of a rectifier power supply, and the other end is connected with an anode plate.

6. The method of claim 1, wherein the method is characterized by: The temperature measuring thermocouple (12) is a corrosion-resistant thermocouple with a porcelain sleeve, and the porcelain variety of the corrosion-resistant porcelain sleeve is high-aluminum porcelain or high-aluminum oxide porcelain sleeve with an aluminum oxide content of 60wt.% to 85wt.% of the total weight of the ceramic material.

7. The method of claim 1, wherein the method is characterized by: The molten salt transformer (5) is a 3-phase 380V AC input adjustable transformer.

8. The method of claim 1, wherein the method is characterized by: The preparation method of the electrolyte in the preparation material is as follows: the salt raw materials used in the electrolyte formula are sequentially added to a molten salt mixing furnace with a temperature of 790℃, and the sequence is: anhydrous potassium chloride→anhydrous lithium chloride→anhydrous lanthanum chloride→anhydrous cerium chloride→anhydrous samarium chloride→anhydrous magnesium chloride; the furnace temperature is lowered to 690℃, and then anhydrous ferrous chloride and anhydrous cuprous chloride are added to the furnace and stirred uniformly for standby.

9. The method of claim 1, wherein the method is characterized by: The particle size and corresponding purity of the powder raw material used in the consumable anode powder forming material (7) in the preparation material are as follows: the particle size of the hydrogen storage alloy ultrafine powder is less than 600 mesh, or the 600 mesh Tyler standard sieve is used to screen the oversize portion, and the purity is 99.5wt.%; the particle size of the molybdenum powder is less than 800 mesh, or the 800 mesh Tyler standard sieve is used to screen the oversize portion of the commercially available FMo-2 type molybdenum powder, and the purity of the molybdenum powder is 99wt.%; the particle size of the nickel powder is less than 800 mesh, or the 800 mesh Tyler standard sieve is used to screen the oversize portion of the commercially available carbonyl nickel powder, and the purity of the nickel powder is 97wt.%; the particle size of the iron powder is less than 800 mesh, or the 800 mesh Tyler standard sieve is used to screen the oversize portion of the commercially available carbonyl iron powder, and the purity of the iron powder is 99wt.%; the particle size of the copper powder, magnesium powder and selenium powder is 200 mesh, and the purity is 99.5wt.%.

10. The method of claim 1, wherein the hydrogen storage alloy ultrafine powder is characterized by: The amount of consumable anode powder forming material (7) particles scattered on the upper surface of the anode graphite plate in the tank is 1.5wt.%±0.5wt.% of the total weight of the electrolyte in the tank.

11. The method of claim 1, wherein the method is characterized by: In the first step, a molten salt coating plating tank for continuously producing strips is constructed, specifically: In the first step, a molten salt coating plating tank for continuously producing strips is constructed, specifically: ​ The constructed continuous production strip molten salt cladding plating bath is in the shape of an open rectangular cuboid at the top; the material of the bath shell (1) is a metal nickel plate or a nickel-based alloy plate; four strip driving forward guide wheels, two of which are driven guide wheels (9) partially immersed in the liquid electrolyte, and the other two are guide wheels above the plating bath, one of which is a strip driving forward guide wheel (2), and the other is a strip power supply guide wheel (13); a deposited negative carrier strip (3); a lower anode (6) connected to the output positive electrode of the rectifier power supply through a conductive rod; two entropy and stability increasing temperature L-shaped probes (8) connected to the live wire and ground wire of the outlet of the molten salt transformer (5); consumable anode powder forming material (7) scattered on the upper surface of the anode graphite plate in the bath; four anode support porcelain insulators (4) installed at the bottom of the bath; an anode conductive connecting rod (11) connected to the anode; a temperature measuring thermocouple (12) with a porcelain sleeve corrosion-resistant inserted in the plating bath suspension liquid electrolyte; the power supply of the two entropy and stability increasing temperature L-shaped probes is an adjustable block molten salt transformer; the power supply of the anode and cathode in the plating bath is a rectifier power supply (14); the top cover of the bath shell (1) contains a openable cover (15).

12. The method of claim 1, wherein the method is characterized by: In the second step, material preparation, tank loading and pre-plating, the loading procedure and sequence are as follows: first load the tank internals and devices, then load the plating material, open the cover (15) of the tank top cover → install four anode support porcelain insulators (4) at the bottom of the tank → then lay the anode (6) graphite plate on the insulators → screw the anode conductive connecting rod (11) on the anode graphite plate hole and connect the corresponding wires between it and the rectifier power supply (14) → fix the four strip driving forward guide wheels and connect the corresponding wires between the brush of one of the guide wheels and the rectifier power supply → fix the entropy and stability increasing temperature L-shaped probe (8) and connect the corresponding wires between it and the molten salt transformer (5) → fix the temperature measuring thermocouple (12) → transfer the molten salt liquid in the molten salt mixing furnace to the plating bath by hand ladle and make it reach the molten salt liquid level, which is 4 cm higher than the subsequent added strip → sprinkle the particles of consumable anode powder forming material (7) on the upper surface of the anode (6) graphite plate in the tank → start the molten salt transformer (5) to heat or maintain the temperature of the molten salt electrolyte through the entropy and stability increasing temperature L-shaped probe (8) and make the temperature constant at 400°C → use a special strip hook to make the strip pass through the two driven guide wheels (9) in the tank and finally make the deposited negative carrier strip (3) be completely fixed on the four guide wheels.

13. The method of claim 1, wherein the method is characterized by: In the second step, the preparation, the tank loading and the pre-electroplating, the pre-electroplating is specifically as follows: through the actual temperature of the electrolyte displayed by the temperature measuring thermocouple (12) in the electrolyte, taking the temperature range of 400℃±10℃ as the temperature adjusting target, through the increase and decrease adjustment of the output power gear of the molten salt transformer (5) and the adjustment of the distance between the L-shaped probe (8) and the temperature adjusting device, the temperature adjusting target is achieved within the temperature range; the rectifier power supply (14) is started to apply voltage and current to the cathode and anode in the plating tank, the tank voltage Vc and the cathode current density Id are controlled as follows: Vc = 3V±1.2V, Id = 0.05 A / cm 2 ±0.02 A / cm 2 ; the pre-electroplating is performed for 20 minutes.

14. The method of claim 1, wherein the method is characterized by: The fourth step is strip post-processing and related characterization, which is carried out in the following order: On the basis of the completion of molten salt cladding plating, the strip post-processing and related characterization are carried out in the following order: ① Turn off the rectifier power supply and molten salt transformer power supply → remove the completed cladding plated strip → use a special porcelain scoop to remove the liquid electrolyte from the tank to the cold mold → cool the strip and electrolyte to room temperature; ②The strip cooled to room temperature is washed with high-pressure water gun to remove the entrained molten salt, dried in a hot air oven, and the section of the strip pre-plated at the front end is cut off for the next production to be welded to the front end of the new strip for secondary or multiple use or utilization; three samples are taken from different parts of the finished strip with a sampling hole with a diameter of 20 mm; ③The weights of the three samples taken from the finished strip are accurately weighed with a four-digit balance, which are used as the basis data for subsequent weight gain method characterization.

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