CN113437247B - Method for electrodepositing active substance on battery current collector by using molten salt - Google Patents

Method for electrodepositing active substance on battery current collector by using molten salt Download PDF

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CN113437247B
CN113437247B CN202110710391.6A CN202110710391A CN113437247B CN 113437247 B CN113437247 B CN 113437247B CN 202110710391 A CN202110710391 A CN 202110710391A CN 113437247 B CN113437247 B CN 113437247B
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electrodeposition
battery
nickel
electrolyte
current collector
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CN113437247A (en
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尹东明
王立民
闫慧忠
程勇
梁飞
吴耀明
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Changchun Institute of Applied Chemistry of CAS
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Changchun Institute of Applied Chemistry of CAS
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0438—Processes of manufacture in general by electrochemical processing
    • H01M4/045—Electrochemical coating; Electrochemical impregnation
    • H01M4/0454—Electrochemical coating; Electrochemical impregnation from melts
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/24—Alkaline accumulators
    • H01M10/30—Nickel accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/24—Electrodes for alkaline accumulators
    • H01M4/26—Processes of manufacture
    • H01M4/28—Precipitating active material on the carrier
    • H01M4/29—Precipitating active material on the carrier by electrochemical methods
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

The invention provides a method for electrodepositing an active substance on a battery current collector by using molten salt, belonging to the field of molten salt electrochemistry. The invention solves the main problems that: the method for firmly processing the battery active substance on the current collector of the battery pole piece is provided, so that the capacity and the service life of the battery are improved in a spanning manner. The method comprises three steps of designing and constructing an electrodeposition bath, drying the bath and preparing materials of the electrodeposition bath, loading the bath and a carrier of the electrodeposition bath, and selectively annealing. The invention is mainly used for the fused salt electrodeposition of active substances on the current collector of the battery plate, and has the effects that: the method lays a foundation for the technical barrier of the nickel-metal hydride battery negative plate crossing sintering, lays a foundation for fundamentally solving the technical barrier of thermal shrinkage and cold expansion when antimony (Sb) is used as an active substance of the lithium ion battery, and adds a new tool for balancing the capacity of the positive electrode and the negative electrode and the service life cost in the battery design.

Description

Method for electrodepositing active substance on battery current collector by using molten salt
Technical Field
The invention relates to a method for electrodepositing active substances on a current collector of a battery by molten salt; in particular to a method for performing fused salt electrodeposition on an active material on a current collector of a battery negative electrode.
Background
A "battery" in the title "method for molten salt electrodeposition of an active material on a battery current collector" includes: a single battery (cell), a battery pack (battery), a primary battery or a rechargeable battery thereof, and a photovoltaic battery or a photovoltaic pile; the method for electrodepositing the active substance by the molten salt is suitable for all the batteries mentioned above; two specific batteries which are most used in the current market in two types of batteries, namely a water-based battery and a non-water-based battery, are selected as representative examples to illustrate the method for treating the battery pole piece by electrodeposition; more specifically: the aqueous battery is selected from an alkaline battery (alkaling battery) or a nickel-metal hydride battery (Ni-MH battery or nickel-hydrogen battery for short) in rechargeable batteries, and the nonaqueous battery series is selected from a lithium ion rechargeable battery, and the methods for treating the battery pole pieces by electrodeposition are described by taking current collectors used by the two batteries as representative examples.
For "electrodeposition" in the titled "method for molten salt electrodeposition of active species on battery current collector", electrodeposition (or electrolytic deposition) is a "generic" concept, which includes electrolysis, electroplating and electroforming.
For electrolysis, industrial production of active metals such as rare earth metal, metal lithium, metal sodium, metal potassium and the like is obtained by a molten salt electrolysis mode; the common metal aluminum and the common metal uranium in the atomic energy industry are also obtained by a molten salt electrolysis mode.
For electroplating, metal or plastic products in civil products are electroplated due to various requirements such as corrosion resistance, decoration, reflection, light condensation and the like, the electroplated products are frequently used, and the electroplating is divided into aqueous solution electroplating at room temperature; however, it is less well known for molten salt plating, which is often classified as high temperature plating under non-aqueous electrolytes, commonly used in the military industry industries, such as:
the plating layer of the high-strength steel sheet used by the early helicopter rotor blade and the rotor blade electroplated by the aqueous solution is easy to strip off by air friction, and the plating layer is required to be plated by molten salt, and the molten salt electroplating at high temperature is adopted, so that the plated element in the plating layer and the matrix element reaction product of the matrix layer form a wedge-shaped object, which is equivalent to the situation that the plating layer wedges into the matrix, and the molten salt electroplating has higher tolerance than the aqueous solution electroplating rotor blade for the working condition that the high temperature and the large shearing force formed by the air friction strip off in the flight process of the helicopter. This example is enumerated for the purpose of:
the invention adopts fused salt electrodeposition, which can be specifically attributed to fused salt electroplating, fused salt electrolysis and fused salt electroforming, and is convenient for understanding the patent 'three properties' of the invention adopting the fused salt electrodeposition active substance, the active substance of the battery pole piece is essentially metal or alloy, such as hydrogen storage alloy, a battery designer naturally expects the metal or alloy electrodeposited on the current collector to be firmer and better when being combined with the current collector made of metal material, obviously, the firmness of the metallic active substance electrodeposited on the current collector of the battery is improved by 'order of magnitude' compared with the firmness of the active substance on the battery aqueous solution slurry drawing (glue and blade coating of the active substance).
For electroforming, it is generally defined as: electroforming is a special machining method that uses the principle of electrolytic deposition of metals to accurately replicate certain complex or special shaped workpieces. It is a particular application of electroplating. For example, the current collector used by the electrode plate of the nickel-metal hydride battery and the like of the invention is the 'foamed nickel' commonly used at present, and the so-called electroplating method for obtaining the foamed nickel product is essentially electroforming, which is a product obtained by copying a 'sponge' (polyurethane) porous framework, finally carbonizing the 'sponge' at a high temperature of more than 400 ℃ and gasifying the 'sponge'; obviously, the hydrogen storage alloy (nickel-metal hydride battery negative electrode active material) is continuously electrodeposited on the 'nickel foam' skeleton, which is equivalent to secondary electroforming.
Whether electroplating or electrolysis or electroforming is adopted, when the working condition that two or more than two metal elements need to be electrodeposited simultaneously is much more difficult than the working condition that one metal element needs to be electrodeposited, because each metal element has respective metal precipitation potential, so that a plurality of metal ions are co-precipitated, pulse electrolysis or pulse electroplating or pulse electroforming is an effective method, particularly for the co-precipitation working condition of active metals such as rare earth, the effective method is to replace a common direct current power supply with a pulse direct current power supply, which is the reason for selecting the pulse direct current power supply (Duchen, Liu Ying, Lu Liang, Tang Dy; research on direct current pulse electrolysis Al-La alloy [ J ]; rare earth; No. 14 volume 3 in 1993, P66-69).
The term "molten salt" in the title "method for the electrodeposition of an active material by molten salt on a battery current collector" is more specifically an abbreviation for molten salt (molten salt or molten salts). The electrolyte belongs to a non-aqueous medium, anions and cations are liberated from bound crystal lattices in a molten state to form a 'short-range ordered and long-range disordered' pure positive ionic liquid, and a large amount of molten salt is industrially utilized to manufacture active metal products at high temperature, so people often call the 'high-temperature ionic liquid', and in fact, the scientific development is advanced to the present day, inorganic salt and organic salt are combined with each other to manufacture the ionic liquid at room temperature quite easily; obviously, the high temperature required for fused salt electrodeposition is not required for aqueous solution electrodeposition, because high temperature means high energy consumption and high corrosion, which are advantages of aqueous solution electrodeposition, but lower and inferior to the deposited layer firmness obtained by fused salt electrodeposition, whereas, generally, a fused salt electrolyte at 800 ℃ or above is used for electroplating or electrolysis, which is an advantage that the metal is firmly bonded to the matrix, and high energy consumption, high corrosion and damage to the structural properties of the current collector are inferior, as can be seen: the molten salt solvent system with the melting point of about 352 ℃ can be regarded as a medium temperature system for balancing and optimizing the advantages of high temperature and low temperature-disadvantage (Wu Guangming, Summinck, Du forest; research progress of molten salt [ J ]; chemical progress; 1995, No. 5P 5-27).
In addition, the invention selects about 352 ℃ LiCl-KCl eutectic point mixed salt as the solvent of the electrodeposition electrolyte, and changes the adverse factor of metal fog (metal fog) into the beneficial factor by potential. The term "metal mist" as used herein means that, as early as 1807 years, when potassium metal was produced by fused salt electrolysis by a chemist Davy (British chemical) in the United kingdom, the metal precipitated on the cathode was again dissolved in the electrolyte, and the colorless melt turned into reddish brown. Later, many scientists discovered similar phenomena, the well refers to the phenomenon as 'metal fog', the metal fog of rare earth in chloride fused salt is not neglected, obviously, the solvent reference point of the chloride fused salt is fixed at 352 ℃, fused salt electrodeposition is carried out at about 400 ℃, the diffusion speed of the generated metal fog is far lower than 800 ℃, the metal fog generating points are reasonably distributed at the position beneficial to cathode electrodeposition (as shown in figure 2), the generated metal fog is deposited on a target current collector in an 'cladding plating' mode under the double driving of electric field force and bubble force, the quantity of active substance elements of the current collector is increased, adverse factors are beneficial factors (Von force, Chunge, Li, Tang & gtze, research on dissolution process of various neodymium in chloride fused salt by using a transparent electrolytic cell [ J ]; Chinese rare earth science report; Vol.9 of 1991, No. 3, p202-204).
For an "active material" in the titled "method for molten salt electrodeposition of active material on battery current collector": the term "active material" in a battery refers to a key material that plays a role in energy storage and energy conversion of the battery, and may be a single metal, a single compound or an intermetallic compound, an intermetallic compound or an alloy constructed by a plurality of metals, or a composite constructed by a plurality of compounds.
For nickel-hydrogen batteries (nickel-metal hydride batteries) in the aqueous battery series, the active material on the negative electrode is a hydrogen storage alloy. In the commonly used rare earths AB 5 Type hydrogen storage alloy (LaNi) 5 System), it was thought that, in the six thermodynamically stable intermetallic compounds in the lanthanum-nickel phase diagram (see fig. 5), the specific LaNi could not be found before 2000 5 The intermetallic compound is more suitable as the active material of the cathode of the nickel-hydrogen battery, and the other five intermetallic compounds La in the phase diagram 3 Ni、La 7 Ni 3 、LaNi、La 2 Ni 3 、LaNi 2 、LaNi 3 And La 2 Ni 7 Has been ignored by the battery world; in this century, there were suddenly findings of LaNi in La-Ni phase diagram 3.5 (La 2 Ni 7 ) In which a small amount of magnesium is substituted for lanthanum metal, which is greater than LaNi 5 The electrochemical capacity of the anode is more than 30 percent higher; thus, containing magnesium AB 3 (also known colloquially by the battery community as A) 2 B 7 System or "La-Mg-Ni system") hydrogen storage alloy is used for nickel-hydrogen battery cathode active material, and has become a high point of priority for intellectual property rights of various countries, and dozens of inventions such as application or publication numbers CN108172807B, CN101538660A, CN108172807A, CN108172817A and CN107845779A disclosed by the chinese patent office are all magnesium-containing AB 3 Or is called A 2 B 7 The design and manufacture of the system or La-Mg-Ni system hydrogen storage alloy. It is clear that the invention deposits LaNi with very accurate metering ratio by co-electrodeposition 5 Do face many technical barriers, however, in view of the La-Ni phase diagram of FIG. 5 3 Ni、La 7 Ni 3 、LaNi、La 2 Ni 3 、LaNi 2 、LaNi 3 、La 2 Ni 7 And LaNi 5 All have hydrogen storage function, and the non-stoichiometric compounds of the eight intermetallic compounds also have hydrogen storage function, even La 2 Ni 7 And the electrochemical specific capacity ratio LaNi of chemical hydrogen storage after a small amount of magnesium is used for replacing lanthanum in non-stoichiometric ratio 5 And is high, so that the co-electrodeposition of the La-Mg-Ni series of the present invention does not present a technical barrier that cannot be overcome.
Similarly, for lithium ion batteries in nonaqueous battery series, graphite microsphere carbon materials are widely used as active substances on the negative electrode of the lithium ion batteries, and in recent years, metal tin and antimony are found to have higher electrochemical specific capacity instead of graphite microsphere carbon in the battery industry, and the tin and antimony are used as active substances on the negative electrode of the lithium ion batteries to become the highest point of the occupation of intellectual property rights of all countries in the world, and dozens of invention patents such as the published application numbers of Chinese patent offices are CN201110222422, CN201810085476, CN201810357269, CN201810499648, CN201910779639, CN 2010791797979661, CN 201910780661 0780520, CN201710541003, CN 10415515515584, CN 201610210279445, CN201480011553, CN201210570457, CN200910196920 and CN 200910040040040040048319 are all design and manufacture patents related to the tin and antimony are used as active substances on the negative electrode of the lithium ion batteries by replacing graphite microsphere carbon by single or mixed with the tin and antimony. One recognition error area is: the metal tin is a common solder, the tin is melted, then the copper foil of the negative current collector of the lithium ion battery is immersed in the molten tin, and a layer of tin is adhered on the surface of the copper foil of the current collector by a hot dipping method, so that the tin is not required to be electrodeposited on the copper foil which is far away like the method provided by the invention. The recognition error is mostly not a person skilled in the battery industry, and an example of a similar license is: the copper foil used for the current collector of the lithium ion battery in the battery industry is always 'electric copper foil', or the copper foil manufactured by an electrodeposition method, but the copper foil obtained by a rolling method (multi-pass rolling) is not used, because the electric copper foil is far better than the copper foil obtained by the rolling method in various performances such as lithium hexafluorophosphate corrosion resistance, lithium dendrite generation prevention and the like. Obviously, without redundancy, a layer of tin or antimony or an alloy of the tin or antimony or the alloy of the tin or antimony is adhered to the surface of the copper foil of the current collector by a hot dipping method, which is equivalent to that of a rolled copper foil used for the current collector of the lithium ion battery.
In summary, the prior art of the negative active material of the nickel-hydrogen battery in the current aqueous battery and the lithium ion battery in the non-aqueous battery is combined on the current collector of the battery through a wet slurry drawing process, which can be said as follows: the negative active material of the battery is adhered to the current collector of the battery through 'glue', but the method for electrodepositing the battery active material on the current collector of the battery by utilizing the invention has no patent publication and article report; in particular, a novel method for electrodepositing an active substance onto a battery current collector by using medium-temperature molten salt is not disclosed in a patent publication and an article for solving a plurality of technical defects in the prior art, such as poor or tight combination between the battery active substance and the battery current collector or limited loading capacity of the active substance on the current collector.
Disclosure of Invention
In view of the serious lack of a revolutionary method for firmly preprocessing or processing active substances on a pole piece current collector of the rechargeable battery, the technical defect seriously restricts the capacity and service life span spanning promotion of the rechargeable battery, particularly the capacity and service life spanning promotion of the water-based and non-water-based rechargeable batteries which are widely used at present; in order to make up for the technical defect, the invention aims to provide a method for electrodepositing an active substance on a current collector of a battery by using molten salt, in particular to a method for electrodepositing an active substance on a current collector of a battery cathode.
The invention is mainly realized by adopting the following technical scheme of a three-step method:
designing and constructing an electrodeposition tank; secondly, drying and preparing materials of the electrodeposition bath; and thirdly, the loading of the electro-deposition tank and the carrier are deposited and selectively annealed.
Wherein:
the first step is as follows: designing and constructing an electrodeposition cell:
the electro-deposition tank designed by the invention is cylindrical, the structure-function integrated material for constructing the wall of the electro-deposition tank is mainly compact graphite, and the wall of the tank is used as a receptor of electrolyte and also used as a part of inert anode; the other two anodes are consumable anodes which are made of metal or alloy and are respectively arranged at the bottom of the electrodeposition tank and the upper part of the electrodeposition tank, and the product in the consumable anode consumption process is a chemical element required by the synthesis of the battery active substance; the cathode of the electrodeposition tank is arranged on the central axis of the cylindrical electrodeposition tank, and the electrolyte contained in the electrodeposition tank is chloride molten salt in the mixed halogen salt. A schematic cross-sectional view of the electrodeposition cell designed and constructed is shown in fig. 2.
The second step is that: drying and material preparation of the electrodeposition tank:
the temperature of the drying tank is 200 ℃ and the time is 4 hours.
Secondly, the electrolyte formula in the preparation material is as follows: 51 wt.% KCl-43 wt.% LiCl-1 wt.% MgCl 2 –5wt.％LaCl 3 Or 51 wt.% KCl-43 wt.% LiCl-2 wt.% MgCl 2 –4wt.％LaCl 3 Or 54 wt.% KCl-45 wt.% LiCl-1 wt.% LaCl 3 (ii) a The preparation method of the electrolyte with the formula comprises the following steps: "the salt raw materials used in the electrolyte formula are fed into a furnace with the temperature of 790 ℃ according to the following sequence: anhydrous potassium chloride → anhydrous lithium chloride → anhydrous magnesium chloride → anhydrous lanthanum chloride.
The formula of the consumable anode powder forming material in the prepared material is as follows: 3.3 wt.% Mg-0.7 wt.% Ni-96 wt.% AB 5 Type Hydrogen storage alloy or 3 wt.% Mg-1 wt.% Ni-96 wt.% AB 5 Type hydrogen storage alloy or 78 wt.% Cu-16 wt.% Fe-6 wt.% AB 5 A hydrogen storage alloy of type; the granularity and the corresponding purity of the powder raw materials used in the formula are respectively as follows:
the average particle size of the metal magnesium powder is 100 meshes, and the purity of the metal magnesium powder is chemical purity; metallic nickel powderIs commercially available carbonyl nickel powder with the particle size of 800 meshes to 980 meshes and the purity of 99 wt.%; AB 5 The powder of the type hydrogen absorbing alloy had a particle size of 200 mesh. + -. 50 mesh and a purity of 99.8 wt.%.
The consumable anode sheet material in the material preparation of the invention is as follows: a nickel plate having a thickness of 0.5mm and a purity of 99.8 wt.% or a nickel plate having a thickness of 1mm and a commercially available model of Sn 90 Sb 10 In the solder sheet of Sn-Sb alloy of (1), wherein Sn 90 Sb 10 A commercially available model represents a tin antimony alloy solder sheet with an alloy composition of 90 wt.% Sn to 10 wt.% Sb.
The consumable anode bar material in the stock preparation of the invention is as follows: a nickel metal rod having a diameter of 10mm and a purity of 99.8 wt.% or a tin-antimony alloy rod having a diameter of 10mm and an alloy composition of 47.5 wt.% Sn-52.5 wt.% Sb.
The negative electrode carrier material to be deposited in the material preparation of the invention is as follows: commercially available nickel foam or commercially available nickel plated steel belts or commercially available stainless steel mesh. The carrier material has the following commercial specifications: the surface density of the foamed nickel is 250g/m 2 ±20g/m 2 (ii) a The thickness of the nickel-plated steel strip is 0.2 mm; the stainless steel screen mesh is 200 meshes.
The third step: the loading and carrier of the electrodeposition bath are deposited and selectively annealed
The invention 'loading of electrodeposition tank' comprises the following steps: respectively placing the cut consumable anode sheet material and the consumable anode bar material into the bottom and upper designated positions of the electrodeposition tank at room temperature, and then heating the outside of the electrodeposition tank, wherein the external heating temperature is controlled at 375 ℃, 380 ℃ or 400 ℃; adding the solid fragments of the electrolyte which are melted and prepared according to the formula into the electrodeposition tank one by one, continuously melting the electrolyte into liquid along with the solid, and stopping adding the electrolyte when the liquid level just submerges the annular consumable anode bar in the electrodeposition tank; then, feeding prepared consumable anode powder molding materials into the electrodeposition tank, wherein the feeding amount of the molding materials is 10 times of the weight of the prepared deposited anode carrier materials; and then, hoisting the deposited cathode carrier material, inserting a temperature thermocouple probe and adjusting the stable electrodeposition temperature to prepare for the next electrodeposition.
The electrodeposition temperature of the 'carrier of the electrodeposition bath is deposited' is 400 +/-2 ℃ or 380 +/-2 ℃ or 375 +/-2 ℃; the electrodeposition time was 10 minutes or 15 minutes.
And the selective annealing is carried out on the current collector on which the active substance is deposited for the negative electrode of the nickel-metal hydride battery, wherein the annealing temperature is 500 ℃, the annealing time is 1 hour, the temperature is reduced to 260 ℃, the temperature is kept constant for 2 hours, and the annealing protective atmosphere is argon.
The invention has the beneficial effects that:
one is as follows: the method lays a firm foundation for the technical barrier of crossing sintering of the negative plate of the nickel-metal hydride battery, and particularly comprises the following steps:
alkaline batteries are known in the art: the nickel-metal hydride battery is based on a nickel-cadmium battery, and only the negative electrode of the nickel-metal hydride battery and the negative electrode of the nickel-metal hydride battery are different in active material; the nickel-cadmium battery is improved by more than 70 years of industrial technology, the 'double sintering' technology is realized, or sintered polar plates (commonly called porcelain sheet type biscuit polar plates in factories) can be used for both the positive polar plate and the negative polar plate, and the service life of the 'double sintered' nickel-cadmium battery can exceed 30 years even in a floating charge state, so that the requirement of submarines and the like on equipment which requires more than 10 years for replacing rechargeable batteries and enables working conditions to be in service is met. The 'double-sintered' nickel-cadmium battery has longer service life than the 'slurry' plate battery, and one of the main reasons is that the active materials on the positive and negative electrode plates are firmly combined with the current collector of the electrode plate. In contrast, the positive plate of a nickel-metal hydride battery, although it may be borrowed from the sintered positive plate of a nickel-cadmium battery, has not yet crossed the technical barrier of "sintering"; the method for electrodepositing the active substance on the current collector of the battery by using the molten salt lays a firm foundation for the technical barrier of crossing the sintering of the negative plate of the nickel-metal hydride battery, obviously, on the basis of the molten salt electrodeposition, functional materials with a conductive agent and a yielding agent, such as a mixture of multilayer graphene, superfine graphite powder and the like, are subjected to intermittent hybrid molten salt coating plating technology in the electrodeposition process, so that the functional materials are simultaneously deposited on key hole sites of the current collector, and the subsequent heat treatment temperature is raised to the sintering temperature of a biscuit polar plate; obviously, the nickel-metal hydride battery crosses the technical barrier of 'double sintering' and a great deal of work is needed to do, so the beneficial effect of the invention in crossing the technical barrier of 'double sintering' can only be called as the layer of 'laying a firm foundation for the technical barrier of' crossing sintering 'of the negative plate of the nickel-metal hydride battery'.
The second step is as follows: the solid foundation is laid for fundamentally solving the technical barrier of thermal shrinkage and cold expansion of antimony (Sb) serving as an active substance of the lithium ion battery, and specifically comprises the following steps:
metal specialties are well known to the expert: all metals in the periodic table, except three metals, are all expanded with heat and contracted with cold, or the coefficient of linear expansion or volume expansion is increased along with the temperature rise, and the three metals which are contracted with heat and expanded with cold are antimony (Sb), bismuth (Bi) and gallium (Ga). Sn long existing in tin solder markets of various countries in the world 95 Sb 5 And Sn 90 Sb 10 Two grades of solders (5 wt.% or 10 wt.% of antimony is added in pure metallic tin) aim to solve the problem that microcracks are generated in a welding cooling transition region due to cold shrinkage of main material tin during the welding solidification process of the tin solders, and the generation of cracks is reduced due to the increase of cold expansion element antimony during the cooling process.
Lithium ion battery negative electrode materials with specialized materials are known in the same lines: antimony is used as a lithium ion battery cathode active material, although the material has high electrochemical specific capacity, the antimony is quickly pulverized with the increase of the number of cycles of charging and discharging to cause the battery capacity to be attenuated, although the attenuation mechanism of the battery capacity is complex, researchers are inevitable to guess that the antimony is related to the thermal shrinkage and cold expansion characteristic of antimony, and in order to solve the problem, many researchers add copper (Cu) element in the process of synthesizing a coating carbon antimony or antimony oxide powder active material in a liquid phase to inhibit the capacity attenuation to a certain extent; because copper (Cu) is one of the metal elements with the volume expansion coefficient which is greatly increased along with the temperature increase in the 'expansion on heating and contraction on cooling' element; this idea is the same as tin solder "5 wt.% or 10 wt.% antimony is added to pure metallic tin", however, the experts in lithium ion battery design believe this approach is a palliative but not a fundamental one.
The design of lithium ion batteries is known in the same lines: the consensus of the mainstream lithium ion battery design experts is that: in terms of current developments of current lithium ion battery negative electrode current collector materials, for carrying antimony (Sb) as a lithium ion battery negative electrode active material, the preferred order of the current collectors from high to low is: antimony-containing foam brass → stainless steel mesh → perforated electrodeposited copper foil → plain (non-porous) electrodeposited copper foil; according to the electrodeposition method, for a copper current collector, whether foam brass or an electro-copper foil, antimony subjected to thermal shrinkage and cold expansion is embedded into copper subjected to thermal expansion and cold contraction, the thermal expansion and contraction are mutually counteracted in the thermal shock process of joule heat generated by the current collector due to charging and discharging, and a solid foundation is laid for fundamentally solving the technical barrier of the thermal shrinkage and cold expansion of antimony (Sb) serving as an active substance of a lithium ion battery on the aspect that the current collector is in firm contact with the active substance; compared with the method of adding copper (Cu) element in the process of synthesizing and coating carbon antimony or antimony oxide powder active substances in a liquid phase to restrain capacity attenuation, the method can be called a relative 'permanent cure' method.
And thirdly: a new tool is added for 'anode and cathode capacity-service life cost balance' in battery design:
cell design is well known: in the design process of the usage of the active materials of the positive and negative electrodes of the battery, because the cycle service lives of the positive and negative active materials are different, according to the capacity contribution rate, the active material of the short-life electrode plate is larger than the capacity design of the active material of the long-life electrode plate, or the active material of the electrode plate is more than the active material of the counter electrode plate; so that the battery can achieve the maximum charge-discharge cycle service life as a whole.
For example: for nickel-metal hydride batteries, an AA-type cylindrical rechargeable battery with a capacity of 2000mAh is to be designed, and the design scheme is usually that the commercially available specific capacity of the positive electrode active material is 250mAh/g "spherical nickel" (nickel hydroxide) 8 g; the negative active material is 10 g of hydrogen storage alloy powder with the specific capacity of 300 mAh/g; or the positive electrode capacity is adopted: a design of "battery capacity positive limit" in which the negative electrode capacity is 1: 1.5; this is because the nickel-metal hydride battery is a 'negative limiting' battery, or the decay rate of the charge-discharge cyclic use capacity of the negative hydrogen storage alloy powder is faster than that of the 'spherical nickel' capacity of the positive electrode, if the initial capacities of the positive and negative electrode plates are all designed to be 2000mAh, the charge-discharge cyclic use of the battery is up to 1000 weeks, and the capacity of the positive electrode plate taking the 'spherical nickel' as an active substance is attenuated to 1950 mAh; the capacity of a negative electrode plate taking hydrogen storage alloy powder as an active substance is attenuated to 1900 mAh; the capacity of the entire battery is represented by 1900mAh, which is why it is called a "negative limiting" battery. Therefore, in order to enable the battery to have the maximum charge-discharge cycle service life as a whole, the active substance is added at the beginning of the design of the negative electrode to enable the capacity of the negative electrode to be higher than that of the positive electrode so as to avoid negative limitation caused by the difference of the attenuation speed of the capacities of the positive electrode and the negative electrode; the positive-negative capacity ratio of 1:1.5 is only the design ratio of a common E-type battery, and for some P-type nickel-metal hydride batteries with wide temperature power, the ratio is larger. Obviously, a larger ratio means that more hydrogen absorbing alloy powder as a negative electrode active material is used, and the battery cost is higher.
According to the invention, the active substance (hydrogen storage alloy) is deposited on the negative current collector of the nickel-metal hydride battery in an electrodeposition mode, and as the foamed nickel of the negative current collector is connected in an alloying mode, the initial capacity of the negative electrode is increased, and the attenuation speed of the negative electrode capacity, namely 'yishierjiu', is reduced; therefore, only a certain amount of active substances are electrodeposited on the foamed nickel of the negative current collector in advance through molten salt, compared with a pure slurry drawing method, the amount of hydrogen storage alloy powder is increased by drawing slurry on the foamed nickel of the negative current collector, the battery cost is reduced by a certain amount, or the following steps are carried out: a new tool is added for balancing the anode and cathode capacity and the service life cost in the battery design.
Drawings
Fig. 1 is a technical flow chart of a three-step method for performing fused salt electrodeposition on an active material on a battery current collector according to the present invention.
FIG. 2 is a schematic cross-sectional view of a molten salt electrodeposition of active species on a current collector of a battery of the present invention; in fig. 2:
1 is a silicon carbide heating rod which is used for externally heating the electrodeposition bath.
2 is a 2mm thick 'iron coat' made of low carbon steel, and has three functions: first, structural support of the electrodeposition cell; secondly, the inner container of the electrodeposition tank made of graphite material which is closely contacted with the inner container is subjected to uniform heat conduction, or in other words, the inner container receives the radiation heat of the silicon carbide rod and transfers the radiation heat to the graphite material to be more uniform; and thirdly: the conductive electrode lug is convenient for welding the electrode lug of the electrodeposition tank made of the anode metal material.
3 is an electrodeposition tank 'inner container' made of compact graphite, and has four main functions: firstly, a high-temperature resistant and corrosion resistant 'receptor' for bearing materials such as electrolyte in an electrodeposition bath; secondly, a common component of a non-consumable or low-consumable or inert anode in the electrodeposition tank; thirdly, one of the conductors of the closed loop in the electrodeposition process is maintained; and fourthly, maintaining one of the reversible heat conductors which run at constant temperature such as electrolyte in the electro-deposition tank.
4 is an upper consumable anode metal rod or alloy rod, which has two main functions: firstly, anode gas generated by an inert graphite anode which climbs upwards is generated, or chlorine gas and chlorine gas react at high temperature, and cations in halogen salt of one product of the anode gas is one of raw materials of a deposited cathode carrier or one of raw materials required by a negative electrode active material of a battery; and the second one also serves as an anode.
5 is a lower consumable anode metal floor and an alloy powder forming material block, and has the main functions of two: firstly, an active material ion source for continuous electrodeposition of battery active material obtained by electrodeposition; and the second one also serves as an anode.
6 is an electrolyte for electrodeposition or a mixed high-temperature molten salt.
And 7, a cathode clamp for the deposited negative electrode carrier material.
And 8 is a deposited negative electrode carrier material.
9 is a metal mist generated by a metal or alloy immersed in the high-temperature molten salt.
10 is a temperature thermocouple probe in the electrodeposition bath.
11 is an anode tab of the electrodeposition bath.
12 is an electrodeposition bath outer shell formed by combining refractory bricks and a stainless steel plate.
13 is a feedback thermocouple probe for heating, temperature measuring and controlling inside and outside the electrodeposition bath.
Fig. 3 is a graphical comparison of representative morphology before and after deposition of molten salt electrodeposited active material on a current collector of a battery of the invention.
The fused salt electrodeposition is characterized in that in a chloride fused salt system, a foamed nickel material which is usually used as a current collector of a nickel-metal hydride secondary battery pole piece is used as a cathode in a fused salt electrodeposition tank, graphite and metal or alloy are used as an inert and consumable anode in the fused salt electrodeposition tank, mixed salt which is close to the lowest eutectic point of lithium chloride and potassium chloride is used as a solvent in an electrodeposition electrolyte, and anhydrous magnesium chloride and anhydrous lanthanum chloride are used as solutes in the electrodeposition electrolyte, and more specifically:
the specific electrodeposition electrolyte composition was initially 51 wt.% KCl-43 wt.% LiCl-1 wt.% MgCl 2 –5wt.％LaCl 3 The method is characterized in that the electrochemical product of the anode in the electrodeposition process, namely atomic chlorine and halogen salt generated by the in-situ reaction of high-activity chlorine molecules and consumable anode metal or alloy are used as a replenishing source of deposited metal ions required by continuous electrodeposition, and more specifically:
the original materials of the deposited metal ion replenishing source spring put into the electrodeposition tank are metallic nickel, metallic magnesium and commercially available AB 5 The raw material is in the form of cold static pressure forming blocks such as sheets, bars and powder, and the chemical composition of the powder cold static pressure forming blocks is 3.3 wt.% Mg-0.7 wt.% Ni-96 wt.% AB 5 。
At the electrodeposition temperature of 400 +/-2 ℃; using a pulse type electrolytic direct current power supply, the 'reactant-product' in the electrodeposition tank is close to electrodeposition in the form of 'closed circulation in the tank'; in the figure, (1) is the shape of the foam nickel which is put into an electrodeposition tank before electrodeposition and electrification; (2) after being electrified for a period of time, the shape of the deposited nickel foam is taken out from the electrodeposition tank.
Fig. 4 is a V-T diagram (voltage-time charge-discharge relationship) of representative charge-discharge of molten salt electrodeposition active materials on the current collector of the battery of the present invention. The graph is obtained by a test of the charge and discharge curve obtained by an exploratory preliminary experiment of the present invention, in which the electrodeposition conditions of example 1 and example 2 are mainly used, and the normal condition test of examples 1 and 2 is different: and (3) electrodepositing for 3 minutes by using a pulse direct current power supply, taking out the deposited battery cathode current collector from the molten salt, washing away the coated molten salt by using a water gun, directly placing the molten salt into a simulated battery for measurement after air blow-drying without annealing at 500 ℃, wherein the charging current density adopted during the measurement is 4mA/g, the charging time is 21 hours, the discharging current density is 10mA/g and the discharging cut-off voltage is set to be 0.8V. The charge-discharge curves of the two deposition test results are combined on a graph for the convenience of comparison during characterization by respectively using the foamed nickel and the nickel-plated steel strip as electrodeposition carriers.
Curves (1) and (2) in the figure are respectively based on the nickel foam as the deposited carrier and have the charging and discharging curve characteristics in the simulated battery, and similarly, curves (3) and (4) are respectively based on the nickel-plated steel strip as the deposited carrier and have the charging and discharging curve characteristics in the simulated battery. As can be seen, the deposited negative current collector of the battery shows significant characteristics of the deposited active material of the battery only after 3 minutes of electrodeposition; compared with two different deposited carriers, the method has the advantages that the nickel foam carrier can obtain ideal battery negative active substances by electrodeposition, which is obviously easier than a nickel-plated steel strip, and mainly the electrodeposition of the method is closer to 'electroforming' active substances, porous nickel foam is more suitable for three-dimensional 'electroforming', and the nickel-plated steel strip is more suitable for planar 'electroplating'; in addition, one non-negligible element is: active substances deposited on the plane of the nickel-plated steel strip are more easily washed away by water of a high-pressure water gun in a cleaning link without annealing at 500 ℃ or homogenizing magnesium contained.
FIG. 5 is a representative active mass for molten salt electrodeposition of active mass on a battery current collector of the present inventionOne of the binary phase diagrams. As for the negative electrode active material of a nickel-metal hydride secondary battery, the fact is true that the intermetallic compound, solid solution alloy, and mixed crystal or peritectic alloy capable of reversibly absorbing-desorbing hydrogen elements in the electrochemical cell are "negative electrode active materials of a nickel-metal hydride secondary battery" in a broad sense, and the thermodynamically stable intermetallic compounds 8 shown in fig. 5 include: la 3 Ni、La 7 Ni 3 、LaNi、La 2 Ni 3 、LaNi 2 、LaNi 3 、La 2 Ni 7 And LaNi 5 (ii) a As the cathode active material of the nickel-metal hydride secondary battery is more or less in electrochemical capacity and more or less in battery cycle life, the research and understanding of the invention do not exclude that La with higher electrochemical capacity and longer cycle life is found out x Ni y Systems, such as where LaNi was originally thought to be 5 Has the highest electrochemical capacity, and recently people are in La 2 Ni 7 In the presence of a small amount of magnesium instead of lanthanum, the ratio of LaNi is found 5 Not only is it much higher by 30%, but as a phase diagram, only intermetallic compounds recognized as thermodynamically stable are generally given, and not much intermetallic compounds between La and Ni are recognized, such as LaNi 2.28 As the battery active material, "stable" and "unstable" are not absolutely essential. This phase diagram is given to facilitate the same line's understanding of the ' battery active material ' among the ' molten salt electrodeposition of active material on battery current collector ' of the present invention.
FIG. 6 is a binary phase diagram of two metals involved in the consumable anodic tin-antimony alloy bar of the present invention; the relation between the binary alloy composition of the consumable anodic tin-antimony alloy rod according to the invention and the temperature is revealed in (1) of the figure, from which it can be seen that: the melting point of the alloy is 435 ℃ when the tin-antimony alloy rod has a composition of "47.5 wt.% Sn-52.5 wt.% Sb", the alloy rod is still not in the solid state when the alloy rod is immersed in molten salt at 375 ℃ ± 2 ℃, however, the molten salt temperature differs from the melting temperature of the alloy by only 60 ℃, which makes it easier for the alloying elements on the alloy rod to be consumed during its operation as a consumable anode, or to enter the molten salt to provide a source for the deposited battery active material, the phase diagram being introduced to facilitate a cognate understanding of the principle of designing a consumable anode according to the present invention.
Detailed Description
The present invention will be further described with reference to the following specific examples; in order to make those skilled in the art better understand the technical solution of the present invention, the detailed description of the embodiment of the present invention and the corresponding design basis or principle are used to achieve the purpose of making those skilled in the art better understand the technical solution of the present invention.
Example 1
The negative electrode active material of Re-Mg-Ni (rare earth-magnesium-nickel) series nickel-metal hydride rechargeable battery is electrodeposited on foamed nickel or nickel-plated steel strip.
The first step is as follows: designing and constructing electrodeposition cells
The designed electrodeposition tank is cylindrical, the important structural-functional integration component of the cylindrical tank body is to 'empty' or 'cut' the compact graphite rod from one end into a cylindrical shell with one closed end and a certain thickness, the structural characteristic of the graphite shell is to be used as a receptor of electrolyte, the structural characteristic of the graphite shell is to be used as a partial inert anode, so the electrodeposition tank is designed to be cylindrical, but not square or other heterosexual, and the main reason is to facilitate 'four-field' symmetry. So-called "four fields":
electric field: the electrodeposition cell is essentially an electrochemical cell, known by the same community as: the invention relates to an electrochemical cell, which is characterized in that two common forms of the electrochemical cell are a cell and an electrolytic cell, whether the cell is the cell or the electrolytic cell, most abstains from 'four-field' asymmetry to influence electrochemical reaction and energy conversion, and 'four-field' symmetry is preferred to be electric field symmetry, such as the cell is cylindrical in the most common and most common design shapes, the volume ratio energy and the 'four-field' symmetry degree of the cylindrical cell are always higher than those of a square cell (or called as a stacked cell-pole piece plane superposition), and similarly, the electrolytic cell is a 'electrolytic cell' roughly, when a current collector to be deposited is hung on the central axis of a cylindrical cell body, the direction of electric lines on the side surface of a cylindrical graphite anode is focused on the central axis of the cylindrical cell body, and the electric field symmetry of 360 degrees is formed.
Magnetic field: the fact that electricity is always magnetic is a common knowledge well known to those who learn electromagnetism, and for a simple electrodeposition cell, the orientation of an electric field is closely related to the orientation of a magnetic field, and the symmetric magnetic field of the electric field is easily symmetric.
Temperature field: for self-heating electrolytic cells and the like, the heat source is mainly derived from electrochemical reaction heat generated on a positive electrode and a negative electrode and joule heat generated by leakage current of electrolyte between the positive electrode and the negative electrode as a medium, and obviously, the cylindrical graphite anode side surface is symmetrical relative to the chemical reaction point symmetrical to the central axis and the joule heat generated by the leakage current between the surface and the two electrodes is easy to realize symmetry.
A gravity field: obviously, the strength of the gravity field in the downward direction between the side surface of the cylindrical graphite anode and the cathode with the central axis is also symmetrical around the central axis of each dynamic particle in the electrolyte during the uniform turning of the electrolyte to the axis.
The "four-field" symmetry of electrochemical cells known to the electrochemical experts is not redundant and the design basis or principle of the present invention for designing and constructing an electrodeposition cell is described in detail with reference to fig. 2, which is a cross-sectional view of an electrodeposition cell designed and constructed in accordance with the present invention:
one is as follows: as the corresponding component of the lowest eutectic point of the KCl-LiCl mixed salt is selected as the solvent of the electro-deposition electrolyte, or the weight percentage of the KCl and LiCl mixed salt is as follows: a mixed halide salt with KCl of 55% and LiCl of 45% is the solvent portion of the electrolyte, or a mixed halide salt with a chemical formula of 55 wt.% KCl-45 wt.% LiCl, the lowest eutectic point of the composition being 352 ℃, or above 352 ℃, the mixed salt being capable of melting to a liquid, and vice versa to a solid. Obviously, at room temperature, the molten salt is solid, ions in the molten salt cannot migrate or move because of being fixed on crystal lattices, the temperature must be raised to above 352 ℃, external heating is required, and the silicon carbide heating rod 1 in fig. 2 is an external heating element designed for melting the mixed salt and the like, specifically, the external heating element is a silicon carbide rod or a commonly-called silicon carbide rod in industry. The main reason for adopting the silicon carbide rod instead of adopting the nickel-chromium wire or the iron-chromium-aluminum wire and other electric heating wires as the heating element is as follows: the volatile matter of the fused salt is easy to cause the corrosion of the metal electric heating wire, so that the service life is short, and the silicon carbide rod has strong salt corrosion resistance and is generally the first choice for heating elements of industrial fused salt systems.
The second step is as follows: the electrodeposition cell receptor can be used as anode to select compact graphite, such as the electrodeposition cell 'inner container' 3 in figure 2; the design principle is as follows:
the fused salt electrodeposition temperature is 400 ℃, the temperature is higher compared with the room temperature of aqueous solution electrodeposition, and the fused chloride halide salt has larger corrosion to a receptor at high temperature, and the industry experience of hundreds of years proves that the graphite material is most suitable as a high-temperature fused salt electrodeposition corrosion resistant material, the conductivity of the graphite material can also be used as an anode, and for a chloride fused salt system, the two-step reaction of graphite which is used as the anode after the electrodeposition and an electrolyte interface is carried out is as follows:
first of the two-step reaction, anionic Cl in the electrolyte - Migrate to the graphite-electrolyte interface under the force of an electric field and are oxidized by the anode to chlorine atoms, which are expressed as:
Cl - —e→Cl (1)
the activity of the chlorine atoms generated at the interface of the graphite and the electrolyte is high, the oxidation is strong, and the inertness of the graphite is the root cause for keeping the high-activity and high-oxidation chlorine atoms which are not generated at high temperature to be oxidized.
In the second step of the two-step reaction, chlorine atoms generated at the interface of the graphite and the electrolyte are combined into chlorine gas after being accumulated, and the chlorine gas climbs along the interface and rushes to the liquid surface of the electrolyte, which is the main motive power for self-stirring of molten salt electrolysis, electroplating or electroforming.
Cl+Cl+……nCl→(0.5n+1)Cl 2 ↑ (2)
And thirdly: the active material cations required for continuous electrodeposition are derived from the in-situ synthesis of a part of consumable anode alloy, see the upper consumable anode metal rod or alloy rod 4 and the lower consumable anode metal floor and alloy powder forming material block 5 in the attached figure 2; the design principle is as follows:
the overhead consumable anode metal or alloy rod 4 of FIG. 2 is a nickel rod inserted near the slot of a graphite electrodeposition cell and becomes a consumable anode due to its close connection to the graphite cell, anion Cl in the electrolyte - The atomic chlorine oxidized on the nickel rod directly reacts with the nickel to generate NiCl 2 When dissolved in the dielectric medium, the chlorine gas generated on the inert anode graphite climbs upwards and generates NiCl when encountering the nickel rod when climbing to the position of the nickel rod 2 The electrolyte is also dissolved into the dielectric medium along with the turning of the electrolyte; it is clear that the nickel ions dissolved into the electrolyte by the nickel rod can be part of the nickel source for the Re-Mg-Ni active material for electrodeposition.
The bottom consumable anode metal floor and the alloy powder forming block 5 shown in FIG. 2 are alloy powder or a mixture of alloy particles and metal particles, which is commercially available AB 5 Alloy powder or alloy particles, magnesium powder or a mixture of magnesium particles and nickel carbonyl powder, wherein the metal powder mixture contacts a graphite cell which also serves as an anode, and the powder or particle mixture also serves as a consumable anode, and anion Cl in the electrolyte - Also oxidized to atomic chlorine on the mixture, which reacts directly with the nickel-containing powder or its alloys in the mixture to form NiCl 2 And dissolved into the dielectric, for example, if the mixture powder or granules constitute 3.3 wt.% Mg 0.7 wt.% Ni-96 wt.% AB 5 Then AB 5 The powder and the nickel in the nickel carbonyl powder can be directly reacted to generate NiCl 2 And dissolved in the dielectric, it is evident that the magnesium powder in the mixture, when it acts as consumable anode, is converted into MgCl 2 In the mixture AB 5 The metal La in the powder is converted into LaCl 3 Conversion of Ce to CeCl 3 Metal Nd to NdCl 3 Metallic Co to CoCl 2 The metal Mn is converted into MnCl 2 And so on. Converted into metal ions in various salt forms as the source of active species ions for the continuous electrodeposition of the electrodeposited Re-Mg-Ni active species.
Fourthly, the method comprises the following steps: the design principle of natural turning control of electrolyte in the continuous electrodeposition process is shown in the figure 2 of an electrodeposition bath inner container 3 made of compact graphite and electrolyte 6 of electrodeposition; the design principle is as follows:
in the continuous electrodeposition process, La ions, Mg ions, Ni ions and the like in the electrodeposited electrolyte 6 are deposited on a cathode deposited cathode carrier material 8 to obtain electrons, the electrons are reduced into metal and are deposited on a cathode carrier (such as foamed nickel and the like), after the deposition of the La ions, Mg ions, Ni ions and the like on the surface of the cathode is finished, the La ions, Mg ions, Ni ions and the like in the electrolyte body are supplemented to the surface of the cathode from the electrolyte body through turning under the dual actions of electric field force and 'bubble force', so that the continuous electrodeposition is realized.
The magnitude of the "electric field force" mainly depends on the cathode current density, the cell voltage and the polar distance (distance between the anode and the cathode) in unit time. The 'bubble force' mainly depends on the amount of chlorine gas generated on the non-consumable anode (graphite) in unit time and the shape of the anode surface of the electrodeposition tank; one life example convenient to understand is that a kettle is used for boiling water, when the kettle is used for boiling water with big fire, a large amount of bubbles are generated at the bottom and the side wall of the kettle to promote the water in the kettle to roll, the larger the coal gas fire is, the larger the bubble amount generated by water gasification in unit time is, and the higher the rolling speed of the water in the kettle is; the electric field force of the cylindrical electrodeposition cell is concentrated to the negative electrode, so that the electrolyte turns over directionally. In addition, the main factor affecting the exertion of the "bubble force" is the viscosity of the electrolyte, while the internal factor affecting the viscosity of the electrolyte is the composition of the mixed salt, and the external factor is the temperature, generally speaking: the higher the temperature, the lower the viscosity of the electrolyte, and the more favorable the turning of the electrolyte.
The 'bubble force' of the invention is mainly derived from the area of graphite exposed on the side wall in the inner surface of the cylindrical electrodeposition cell. Or the area of the side of the graphite tank which is in contact with the electrolyte is not less than the bottom area of the inner surface of the graphite tank.
And fifthly: the design principle of the 'metal fog' in the electrodeposition process is shown in the attached figure 2, wherein the metal fog 9 is generated by metal or alloy immersed in high-temperature molten salt, the lower consumable anode metal floor and alloy powder forming material block 5 and the upper consumable anode metal rod or alloy rod 4 are arranged in the metal or alloy; the design principle is as follows:
in a broad sense, all metals or alloys are subjected to high temperature molten salts, the surface of which is more or less dissolved, and the dissolved metal atoms are dispersed into the molten salts to form so-called "metal mist". The size of the metal fog is called the amount of the dissolved metal or alloy, the internal factors are the activity degree of the metal or alloy, the external factors are mainly the temperature, the contact area of the metal and the electrolyte and the composition of the electrolyte, the rare earth metal and the metal magnesium are all active, the relatively large number of atoms dissolved in the molten salt, or roughly referred to as "metal mist" is relatively concentrated or forms a "concentrated metal mist", under the action of directional forces such as 'electric field force' and 'bubble force', metal mist in the electrolyte is transferred to the surface of the cathode, alloying with the cathode deposition increases the element content of the cathode battery active material, the contact area between the lower consumable anode metal floor and the alloy powder forming material block 5 in the attached figure 2 and the molten salt is designed to be larger, one purpose is that the 'metal fog' which is expected to be generated is larger, of course more important than this is the maintenance of sufficient metal oxidation area to obtain sufficient ions of the active species element needed for the electrodeposition cathode; similarly, the top consumable anode metal or alloy rod 4 of FIG. 2 is designed primarily to capture enough active species ions for the chlorine gas to produce an electrodeposited cathode, and secondly, it produces little metal mist to facilitate rapid oxidation of the active species ions for the cathode from the metallic state to the ionic state.
The second step is that: drying and preparation of electro-deposition bath
Step i in the second step: drying the trough: the electrodeposition 'empty tank' is that the upper consumable anode metal rod or alloy rod 4 and the lower consumable anode metal floor and alloy powder forming block 5 which are not added with metal or alloy in the attached figure 2 are not added with the cathode clamp 7 for the deposited cathode carrier material, the deposited cathode carrier material 8 and the electrolyte 6 which is not added with electrodeposition. The empty slot is dried, the aim of the drying is mainly to dry the moisture of the electrodeposition slot and avoid the moisture brought into the electrodeposition slot due to moisture absorption, the temperature of the drying slot is 200 ℃, the time is 4 hours, and the furnace mouth is sealed for standby after the drying slot is finished.
Step II in the second step: preparing an electrolyte raw material: as a mixed salt for the electrolyte, 51 wt.% KCl-43 wt.% LiCl-1 wt.% MgCl 2 –5wt.％LaCl 3 The formula weight proportion of the chemical formula is respectively weighed, or anhydrous potassium chloride, anhydrous lithium chloride, anhydrous magnesium chloride and anhydrous lanthanum chloride are respectively weighed according to the weight percentage, the weight percentage of the anhydrous potassium chloride, the anhydrous lithium chloride, the anhydrous magnesium chloride and the anhydrous lanthanum chloride is respectively 51 percent, 43 percent, 1 percent and 5 percent, and the sum of the weight percentage is 100 percent. Firstly, adding anhydrous potassium chloride into an electrodeposition tank, setting the temperature of a heating temperature controller outside the electrodeposition tank at 790 ℃, and scattering anhydrous lithium chloride on the surface of molten liquid potassium chloride when the potassium chloride is completely molten; when the lithium chloride is melted, scattering anhydrous magnesium chloride into the melted liquid level; after magnesium chloride is completely melted, scattering anhydrous lanthanum chloride into the melted liquid level; and (3) after all the mixed salt is added into the electrodeposition tank, fully stirring for 20 seconds by using a corundum magnetic sleeve to uniformly mix the mixed salt, subpackaging the mixed salt serving as an electrolyte into a cold mould by using a stainless steel spoon, cooling to room temperature, and filling into a dryer for later use.
Step III in the second step: preparing a consumable anode powder molding material: according to 3.3 wt.% Mg-0.7 wt.% Ni-96 wt.% AB 5 The metal powder or alloy powder is respectively weighed according to the formula weight proportion of the chemical formula, or the metal magnesium powder, the carbonyl nickel powder and the commercially available AB are respectively weighed according to the weight percentage 5 The hydrogen storing alloy powder consists of hydrogen storing alloy powder in 3.3 wt%, hydrogen storing alloy powder in 0.7 wt% and hydrogen storing alloy powder in 96 wt%, with the total weight being 100%. Wherein the average particle size and purity of the magnesium powder is commercially available 100 mesh purity and is chemically pure; wherein the nickel carbonyl powder is commercially available nickel powder having a particle size of greater than 800 mesh to 980 mesh and a purity of 99 wt.% for use in an alkaline nickel-hydrogen rechargeable battery conductor; wherein AB 5 The hydrogen absorbing alloy powder is commercially available as a negative active material for nickel-hydrogen rechargeable batteries and has a particle size of 200 mesh ± 50 mesh and a purity of 99.8 wt.%. The weighed three powders were mixed uniformly in a mortar, placed in a mold with a diameter of 13mm, and vulcanized in a vulcanizing machine at 2MPaAnd (5) performing cold static pressing under pressure and the like to form a wafer for later use.
Step IV in the second step: preparing a consumable anode nickel sheet: firstly, measuring the inner diameter of an electrodeposition tank, cutting a nickel sheet which is 0.5mm thick and has the purity of 99.8 wt.% into a circular shape according to the size of the inner diameter, wherein the diameter of the nickel sheet is equal to the inner diameter of a graphite groove in a cylindrical electrodeposition tank, and after electrodeposition begins, putting the nickel sheet on the inner bottom of the electrodeposition tank so that the nickel sheet just covers graphite at the bottom of the electrodeposition tank; the trimmed sacrificial anode nickel sheet stock is ready for use.
Step v in the second step: preparing a consumable anode nickel bar material: firstly, measuring the inner diameter of the V-shaped notch at the upper part of the electrodeposition tank, bending a nickel rod with the diameter of 10mm and the purity of 99.8 wt.% into a ring shape at the position of an upper consumable anode metal rod or alloy rod 4 in the attached drawing 2, wherein the outer diameter of the ring is equal to the inner diameter of the V-shaped notch at the upper part of the electrodeposition tank, repeatedly adjusting the ring to be stably embedded at the V-shaped notch, and reserving the prepared consumable anode nickel rod for later use.
Step vi in the second step: preparing a deposited negative electrode carrier material: the method comprises the steps of cutting the commercially available nickel foam for the current collector of the alkaline nickel-hydrogen rechargeable battery into a rectangle, wherein the length of the rectangle is half of the depth of an electrodeposition groove, the width of the rectangle is half of the inner diameter of the electrodeposition groove, finely weighing the nickel foam or a nickel-plated steel strip by using a four-digit balance, defining the weight as the blank weight of a deposited negative electrode carrier material, calculating the weight gain of subsequent electrodeposition, and reserving the prepared deposited negative electrode carrier material for later use.
Step VII in the second step: preparation of a direct-current pulse power supply: setting the duty ratio of the pulse power supply to be 50%, fixing the frequency gear to a low frequency band and adjusting the frequency gear to be 0.2 Hz; the anode of the output end is connected to the anode tab 11 of the electrodeposition cell in the attached figure 2 or the anode terminal of the iron jacket of the electrodeposition cell; the negative pole of the output end of the pulse power supply is connected to the negative pole clamp 7 for the deposited negative pole carrier material in the attached figure 2 or is connected to the cathode clamp of the electrodeposition tank; and (4) standby the prepared direct current pulse power supply.
The third step: the loading and the carrier of the electrodeposition bath are deposited and selectively annealed:
step i in the third step: the cold tank is filled with a consumable anode nickel sheet material and a consumable anode nickel bar material: at room temperature, the cut consumable anode nickel sheet is horizontally placed at the bottom of an electrodeposition tank, then a consumable anode nickel bar material which is wound into a circular ring shape is embedded in a notch, such as the position of a consumable anode metal bar or an alloy bar 4 arranged in the attached drawing 2, and the purity of the nickel sheet and the purity of the nickel bar are both 99.8 wt.%; then, an external heating power supply is switched on, a knob of an external heating temperature control instrument of the electrodeposition cell is fixed at a position of 400 ℃, and the temperature of the electrodeposition cell is started to rise.
Step II in the third step: adding prepared electrolyte raw materials and consumable anode powder molding materials: in the temperature rising process of the electrodeposition tank, taking out the prepared electrolyte raw material from the dryer, smashing the electrolyte raw material into fragments, putting the fragments into the electrodeposition tank, continuously melting the electrolyte from a solid into a liquid, and stopping putting the electrolyte raw material when the liquid level just submerges the annular consumable anode nickel rod in the electrodeposition tank; the electrodeposition bath is then charged with the ready-to-use consumable anode powder forming material in an amount of 10 times the weight of the ready-to-deposit negative electrode support material.
Step III in the third step: hoisting the deposited cathode carrier material, inserting a temperature thermocouple probe and adjusting the stable electrodeposition temperature: fixing the cut deposited negative electrode carrier material by using a cathode clamp, hoisting the cathode clamp into an electrodeposition tank, wherein the relative position of the cathode clamp is as shown in a deposited negative electrode carrier material 8 in the attached figure 2, and then fixing the cathode clamp above the electrodeposition tank and firmly positioning the cathode clamp; the specific material of the deposited negative electrode carrier material in the embodiment is foamed nickel, and the areal density of the foamed nickel is 250g/m 2 ±20g/m 2 . Then, a temperature thermocouple probe is inserted into the electrodeposition bath, and the insertion depth and the relative position are as shown in the temperature thermocouple probe 10 in the electrodeposition bath in the attached figure 2. Observing the temperature display of the temperature thermocouple inserted in the electrodeposition tank, and if the temperature display deviates from 400 +/-2 ℃, adjusting the knob of the heating temperature controller outside the electrodeposition tank to raise or lower the temperature so that the temperature display of the temperature thermocouple in the electrodeposition tank is stabilized at 400 +/-2 ℃.
Step IV in the third step: electrodeposition and selective annealing: starting a computer for recording three parameters including I (current), V (voltage) and T (time) of electrodeposition in an electrodeposition tank, entering an interface of program software recorded in the computer, then opening a pulse power supply power-on switch, rotating a pulse power supply output current knob to slowly increase output current, and simultaneously observing the surface of electrolyte in the electrodeposition tank, wherein the surface of the electrolyte moves from static to dynamic under the combined action of electric field force and bubble force, and continuously rotating the pulse power supply output current knob to increase or decrease current output according to the flowing state of the surface of the electrolyte until the condition that the electrolyte flows to present the optimal state is adjusted; the outer "three" indifferent signs that the electrolyte flow assumes an optimum state are: the first flag: the slower the electrolyte flow in the electrodeposition cell, the better, the second mark: no significant bubble overflow from the electrolyte surface, third marker: the groove pressure fluctuation is small and the minute fluctuation runs smoothly. And starting timing from the adjustment to the state that the electrolyte flows to present the optimal state, and when the time length reaches 10 minutes, resetting the current output knob of the pulse power supply to zero and closing the power-on switch of the pulse power supply.
Annealing treatment is carried out on a sample piece needing annealing, otherwise, annealing is carried out, a deposited negative electrode blank is taken down from a clamp (see a cathode clamp 7 for a deposited negative electrode carrier material in the attached drawing 2) (see a deposited negative electrode carrier material 8 in the attached drawing 2 and put into an annealing furnace, the annealing furnace is vacuumized, then argon is filled, heating is started for heating, timing is carried out when the temperature reaches 500 ℃, and the temperature is naturally reduced after the time is 1 hour; when the temperature is reduced to 260 ℃, timing is started, the temperature is kept for 2 hours by arranging a heat preservation gear of an annealing furnace, after the annealing furnace is cooled to the room temperature, a heat-treated cathode blank is taken out of the furnace, is cleaned by a spray water gun, is dried by compressed air, is weighed on a balance, and the weight gain is calculated, wherein the weight gain calculation formula is as follows: weight gain-the weight of the vehicle containing the active substance after deposition-the weight of the vehicle before deposition; the weight increment refers to the weight of active substances obtained by deposition, and then the weighed carrier containing the active substances is sealed into a sample bag for later use.
The fourth step: essential characterization oriented to optimization technology and basic research:
characterization of electrochemical capacity: is the active material electrodeposited on the battery negative current collector, is the battery active material deposited on the negative current collector? How much is there deposited? Is the deposition quality satisfactory for various requirements of the cell? Including the need for battery design; these problems require the characterization of the electrochemical capacity of the deposited negative electrode in a "simulated cell", which may be called "mandatory characterization" for the electrodeposition of active materials on the current collector of the negative electrode of the cell; the other series of characteristics such as XRD, DSC, ICP, AC impedance and the like belong to the characteristics required by basic research and advanced technical research.
The characterization technology of battery materials, especially the characterization of electrochemical capacity, has been perfected in recent centuries, and the characterization of electrochemical capacity has become more and more efficient with the appearance of new equipment, such as with the development of battery comprehensive testers, computers and their software technologies, the characterization of electrochemical capacity has been changed from labor intensive to the assembly of analog batteries, and all can be handed to the automatic processing stage of the instruments. The scientific and technological targets and principles of the characterization of battery materials and the characterization of batteries are very different, and the 'simulated batteries' used for the electrochemical capacity characterization are also different from real batteries in nature. For example, the invention is intended to characterize the capacity of the negative electrode material of the battery, and theoretically, the simulation of the relative infinite positive electrode of the battery, the infinite electrolyte, the infinite resistance of the external circuit conductor and the like are required. Theoretically "infinity" or "infinitesimal" does not exist, and in practice the characterization indicates as much implementation as possible: "the large is the small is the large"; for the negative electrode to be characterized in the present invention, the positive electrode capacity is at least 3 times or more greater than the predetermined or pre-estimated negative electrode capacity, the electrolyte is sufficiently "rich" and the current carrying capacity of the external circuit conductor is 3 times or more greater than the current carrying capacity of the predetermined or pre-estimated battery circuit.
In the embodiment, a deposited electrode plate is used as a negative electrode of a battery, a counter electrode representing electrochemical capacity of the negative electrode or a positive electrode of the battery is selected, a sintered nickel anode is selected, the electrochemical capacity of the sintered nickel anode used as the positive electrode of the battery is 3-6 times of the capacity of the electrode plate which is predicted to be deposited, a simulated battery shell is a nylon shell, 6M potassium hydroxide aqueous solution is selected as battery electrolyte, the liquid filling amount of the electrolyte in the simulated battery is 5mm submerging the positive and negative electrode plates of the battery, an electrode outgoing line is a nickel strip with the thickness of 0.5mm and the width of 6 mm; the simulated battery assembling process comprises the following steps: cutting the deposited electrode plate into rectangular plates with the width of 20mm and the length of 25mm, converting the weight of active substances on the electrode plate by using an area ratio method according to the total weight gain, welding an upper electrode leading-out wire (nickel plate) at one end of the electrode plate by using an electric welding machine, wrapping a layer of sulfonated film for an alkaline battery to prevent short circuit with a counter electrode, clamping the deposited electrode plate wrapped with the sulfonated film by using two sintered nickel anodes welded with the electrode leading-out wires to form a traditional sandwich structure, loading the electrode plate into a simulation battery tank, adding prepared KOH aqueous solution electrolyte with the concentration of 6M into the tank, soaking for 12 hours, and respectively connecting the anode and the cathode of the simulation battery with the anode and the cathode of a battery tester; the simulated cell was activated at room temperature at a current density of 60mA/g, and the activation schedule was as follows: for the first time: charging at room temperature of 60mA/g for 1 hour and then discharging to 0.8V; and (3) for the second time: charging at room temperature of 60mA/g for 2 hours and then discharging to 0.8V; and thirdly: charging at room temperature of 60mA/g for 3 hours, then discharging to 0.8V, and the like, and activating to the fifth time; taking the discharge capacity of the sixth charge-discharge data as comparative data of the weight-capacity-specific capacity of the active substance deposited on the pole piece, wherein the sixth charge-discharge system is as follows: charging at a charging current density of 8mA/g for 21 hours at an interval of 1 hour, and then discharging to 0.8V at a discharging current density of 20 mA/g; the data obtained are shown in the corresponding rows and columns of example 1 in Table 1.
Example 2
The difference from example 1 is:
one is as follows: step vi in the second step in example 1: preparing a deposited negative electrode carrier material: replacing the foamed nickel in the foamed nickel' of the current collector of the alkaline nickel-hydrogen rechargeable battery sold in the market with a nickel-plated steel strip, wherein the thickness of the nickel-plated steel strip is 0.2 mm;
the second step is as follows: step iii in the "third step" in example 1: hoisting the deposited negative electrode carrier material and … …, wherein the specific material of the deposited negative electrode carrier material is foamed nickel, the foamed nickel in the foamed nickel is replaced by a nickel-plated steel strip, and the thickness of the nickel-plated steel strip is 0.2 mm;
and thirdly: the "fourth step" in example 1: essential characterization oriented to optimization technology and basic research: … … discharge capacity as a comparative data of the weight-to-capacity ratio of the active material deposited on the pole piece, the data obtained are listed in Table 1 in the row corresponding to example 1 "and replaced by" in the row corresponding to example 2 "in Table 1".
The rest is the same as example 1.
Example 3
The difference from example 1 is:
one is as follows: the "step i in the third step" in example 1: … … the electric deposition bath external heating temperature controller knob is fixed at 400 deg.C, the electric deposition bath heating up "fixed at 400 deg.C" is started, and "fixed at 380 deg.C" is used for replacement.
The second step is as follows: step iii in the "third step" in example 1: … … observing the temperature display of the temperature thermocouple inserted in the electrodeposition cell, if the temperature display deviates from 400 ℃ + -2 ℃, the temperature display of the temperature thermocouple in the electrodeposition cell is stabilized at 400 ℃ + -2 ℃ ' and the temperature of 400 ℃ + -2 ℃ ' is replaced by 380 ℃ + -2 ℃ ' by adjusting the heating or cooling of the heating temperature controller knob outside the electrodeposition cell.
And thirdly: the "fourth step" in example 1: essential characterization oriented to optimization technology and basic research: … … discharge capacity as a comparative data of the weight-to-capacity ratio of the active material deposited on the pole piece, the data obtained are listed in Table 1 in the row corresponding to example 1 "and replaced by" in the row corresponding to example 3 "in Table 1".
The rest is the same as example 1.
Example 4
The difference from example 1 is:
one is as follows: "step iv in third step" in example 1: electro-deposition and annealing: … …, when the time length reaches 10 minutes, the current output knob of the pulse power supply is reset to zero and the '10 minutes' in the pulse power supply power-on switch is closed and replaced by '15 minutes';
the second step is as follows: the "fourth step" in example 1: essential characterization oriented to optimization technology and basic research: … … discharge capacity as a comparative data of the weight-to-capacity ratio of the active material deposited on the pole piece, the data obtained are listed in Table 1 in the row corresponding to example 1 "and replaced by" in the row corresponding to example 4 "in Table 1".
The rest is the same as example 1.
Example 5
The difference from example 1 is:
one is as follows: the "step ii in the second step" in example 1: preparing an electrolyte raw material: as a mixed salt for the electrolyte, 51 wt.% KCl-43 wt.% LiCl-1 wt.% MgCl 2 –5wt.％LaCl 3 The formula weight proportion of the chemical formula is respectively weighed, or anhydrous potassium chloride, anhydrous lithium chloride, anhydrous magnesium chloride and anhydrous lanthanum chloride are respectively weighed according to the weight percentage, the weight percentage of the anhydrous potassium chloride, the anhydrous lithium chloride, the anhydrous magnesium chloride and the anhydrous lanthanum chloride is respectively 51%, 43%, 1% and 5%, and the sum of the weight percentage constitutes 100%... the anhydrous potassium chloride, the anhydrous lithium chloride, the anhydrous magnesium chloride and the anhydrous lanthanum chloride are put into a dryer for standby electrolyte formula and are replaced by a new formula, wherein the new formula after the replacement is: the formula weight ratio of "formula (I) is 51 wt.% KCl-43 wt.% LiCl-2 wt.% MgCl 2 –4wt.％LaCl 3 Or respectively weighing 51%, 43%, 2% and 4% of anhydrous potassium chloride, anhydrous lithium chloride, anhydrous magnesium chloride and anhydrous lanthanum chloride according to the weight percentage, wherein the sum of the weight percentages is 100% ".
And the second step is as follows: the "fourth step" in example 1: essential characterization oriented to optimization technology and basic research: … … discharge capacity was obtained as a comparison of the weight-to-capacity ratio of the active material deposited on the pole piece, and this data is given in Table 1 as "in the row corresponding to example 1" and replaced with "in the row corresponding to example 5" in Table 1.
The rest is the same as example 1.
Example 6
The difference from example 1 is:
one is as follows: the "step iii in the second step" in example 1: preparing a consumable anode powder molding material: according to 3.3 wt.% Mg-0.7 wt.% Ni-96 wt.% AB 5 The metal powder or alloy powder is respectively weighed according to the formula weight proportion of the chemical formula, or the metal magnesium powder, the carbonyl nickel powder and the commercially available AB are respectively weighed according to the weight percentage 5 The hydrogen storage alloy powder comprises 3.3 wt%, 0.7 wt% and 96 wt%, wherein the total of the weight percentages of the hydrogen storage alloy powder and the forming material formula of the consumable anode powder is 100%. multidot. ", and the hydrogen storage alloy powder is replaced by a new formula which is: "3 wt.% Mg-1 wt.% Ni-96 wt.% AB 5 The metal powder or alloy powder is respectively weighed according to the formula weight proportion of the chemical formula, or the metal magnesium powder, the carbonyl nickel powder and the commercially available AB are respectively weighed according to the weight percentage 5 The hydrogen storage alloy powder comprises 3 wt%, 1 wt% and 96 wt%, and the sum of the weight percentages is 100%.
The second step is as follows: the "fourth step" in example 1: essential characterization oriented to optimization technology and basic research: … … discharge capacity as a comparative data of the weight-to-capacity ratio of the active material deposited on the pole piece, the data obtained are listed in Table 1 in the row corresponding to example 1 "and replaced by" in the row corresponding to example 6 in Table 1 ".
The rest is the same as example 1.
Example 7
The difference from example 1 is:
one is as follows: step ii in the second step in example 1: preparing an electrolyte raw material: as..... fill into desiccator for use "in-electrolyte formulation" 51 wt.% KCl-43 wt.% LiCl-1 wt.% MgCl 2 –5wt.％LaCl 3 "replace with a new formulation, which in this embodiment is: 54 wt.% KCl-45 wt.% LiCl-1 wt.% LaCl 3 The new formula is that anhydrous potassium chloride and potassium chloride are respectively weighed according to the weight percentage,The weight percentages of the anhydrous lithium chloride and the anhydrous lanthanum chloride are respectively 54 percent, 45 percent and 1 percent, and the sum of the weight percentages is 100 percent.
The second step is as follows: the "step iii in the second step" in example 1: preparing a consumable anode powder molding material: cold isostatic pressing into disks for use. "internal consumable anode powder molding compound formulation" 3.3 wt.% Mg-0.7 wt.% Ni-96 wt.% AB 5 "replace with a new formulation, which in this embodiment is: 78 wt.% Cu-16 wt.% Fe-6 wt.% AB 5 The new formula is characterized in that the metal copper powder, the iron powder and the commercially available AB are respectively weighed according to the weight percentage 5 The hydrogen storing alloy powder consists of hydrogen storing alloy powder in 78 wt%, hydrogen storing alloy powder in 16 wt% and hydrogen storing alloy powder in 6 wt%, with the total weight being 100%. Wherein the average particle size and purity of the copper powder and the iron powder are 100 meshes sold in the market, and the purities are all chemical purities.
And thirdly: "step iv in second step" in example 1: preparing a consumable anode nickel sheet: … … the cut expendable anode nickel sheet material is replaced by expendable anode Sn-Sb alloy solder sheet of Sn 90 Sb 10 The type represents that the alloy composition is 90 wt.% Sn-10 wt.% Sb; the thickness of the solder sheet was 1mm thick.
And the fourth step: the "step v in the second step" in example 1: preparing a consumable anode nickel bar material: first … … consumable anodic nickel bar stock was replaced with an "inner" nickel bar "that was" tin antimony alloy bar "having a composition of" 47.5 wt.% Sn to 52.5 wt.% Sb ". The melting point of the binary alloy composition "47.5 wt.% Sn-52.5 wt.% Sb" is shown as (1) in fig. 6.
And fifthly: step vi in the second step in example 1: preparing a deposited negative electrode carrier material: taking commercially available nickel foam for alkaline nickel-hydrogen rechargeable battery current collectors, … … the "inner" nickel foam "in backup was replaced with a commercially available stainless steel" screen "that was used to make a 200 mesh" taylor "standard screen.
And the sixth step: the "step i in the third step" in example 1: the cold bath installation … … fixes the electrodeposition bath external heating temperature control instrument knob at the 400 ℃ position, … … starts to replace the "400 ℃ temperature control" with the "375 ℃ temperature control" in the electrodeposition bath heating.
And the seventh step: step iii in the "third step" in example 1: hoist … … was done so that the temperature of the thermometric thermocouples in the electrodeposition cell showed "400 ℃. + -. 2 ℃" stabilized within 400 ℃. + -. 2 ℃ and "375 ℃. + -. 2 ℃" was replaced.
Eight of them: "step iv in third step" in example 1: electro-deposition and annealing: … … the step of 'annealing' in the method for fused salt electrodeposition of active substances on the current collector of the battery negative electrode is omitted, the 'annealing-free substitution' is used, the electrodeposited negative electrode blank is taken out from the deposition tank and cooled to room temperature, and the blank is directly washed by water and dried by compressed air.
Nine steps are as follows: the "fourth step" in example 1: essential characterization oriented to optimization technology and basic research: characterization of electrochemical capacity: the 'characterization method of the water-based rechargeable battery' which takes the discharge capacity of the sixth charge-discharge data as comparison data of the weight-to-capacity ratio of the active substance deposited on the pole piece is replaced by a characterization method of a non-aqueous battery, particularly a lithium ion rechargeable battery in the non-aqueous battery; the simulation battery is assembled in a glove box, wherein:
i, the "fourth step" in example 1: essential characterization oriented to optimization technology and basic research: characterization of electrochemical capacity: … …, the counter electrode characterizing the electrochemical capacity of the negative electrode, or the positive electrode of the battery, the "sintered nickel anode" in the sintered nickel anode "is selected to be replaced by a" lithium sheet "having an electrochemical capacity 300 to 600 times the capacity of the electrode sheet that is predicted to be deposited.
II, the fourth step in example 1: essential characterization oriented to optimization technology and basic research: characterization of electrochemical capacity: … … electrolyte selection 6M aqueous potassium hydroxide solution "the electrolyte selection 6M aqueous potassium hydroxide solution" was replaced with a lithium ion rechargeable battery electrolyte that was typically used and had the following composition: 1mol/LEC + DEC, wherein EC is an abbreviation of ethyl carbonate, DEC is an abbreviation of diethyl carbonate, and the volume ratio of EC to DEC is 1:1.
iii, the "fourth step: essential characterization oriented to optimization technology and basic research: characterization of electrochemical capacity: … … the liquid filling amount of the electrolyte in the simulated battery is 5mm submerging the positive and negative pole pieces of the battery, the electrode lead-out wire is 0.5mm thick, and the nickel strap with the width of 6mm is replaced by 0.5ml of the liquid filling amount of the electrolyte in the simulated battery and 8mm diameter cobalt chromium steel bar of the electrode lead-out wire respectively.
IV, the "fourth step" in example 1: essential characterization oriented to optimization technology and basic research: characterization of electrochemical capacity: … … were cut from the deposited electrode sheet into rectangular pieces … … having a width of 20mm and a length of 25 mm. The "inner" cut into … … rectangular pieces "was replaced by" the deposited electrode pieces were cut into 10mm diameter circular pieces ".
V, the fourth step in example 1: essential characterization oriented to optimization technology and basic research: characterization of electrochemical capacity: … … one end of the pole piece is welded with electrode lead-out wire (nickel piece) … … by electric welder. The ' inner ' welding upper electrode lead-out wire (nickel sheet) ' is replaced by ' the electrode sheet is directly pressed and connected with the inner section of the simulated battery of the cobalt-chromium steel bar lead-out bar without welding '.
Vi "fourth step" in example 1: essential characterization oriented to optimization technology and basic research: characterization of electrochemical capacity: … … the deposited electrode sheet wrapped with "sulfonated membrane" was clamped between two sintered nickel anodes with welded electrode lead wires in a conventional "sandwich" configuration and placed in a simulated cell can … …. The "inner" sintered nickel anode clamped the deposited electrode sheet wrapping the' sulfonated membrane "replacing" two sintered nickel anode sheets with "one lithium sheet"; meanwhile, the sulfonated membrane is replaced by a lithium ion battery nylon diaphragm; and the nylon diaphragm of the lithium ion battery does not need to wrap the deposited electrode plate, and only needs to be placed between the lithium plate and the deposited electrode plate.
VII, the "fourth step" in example 1: essential characterization oriented to optimization technology and basic research: characterization of electrochemical capacity: … … KOH aqueous solution electrolyte with the prepared concentration of 6M is added into the tank and soaked for 12 hours. The "inner" soak for 12 hours "was replaced with" soak for 0.5 hours ".
Viii, "fourth step: essential characterization oriented to optimization technology and basic research: characterization of electrochemical capacity: … … the simulated cell was activated at room temperature at a current density of 60mA/g, with the activation regime: for the first time: charging at room temperature of 60mA/g for 1 hour and then discharging to 0.8V; and (3) for the second time: charging at room temperature of 60mA/g for 2 hours and then discharging to 0.8V; and thirdly: charging at room temperature of 60mA/g for 3 hours, then discharging to 0.8V, and the like, and activating to the fifth time; and taking the discharge capacity of the sixth charge-discharge data as comparison data of the weight-to-capacity ratio of the active material deposited on the pole piece. The internal activation system is cancelled, and the charging and discharging system is replaced by the following system:
charging at a current density of 40mA/g at room temperature, setting the cut-off voltage of the charging to 1.5V, and then discharging at the same current density, setting the cut-off voltage of the discharging to 0V; and after 5 weeks of charge-discharge circulation, taking the discharge capacity of the sixth charge-discharge data as comparative data of the weight specific capacity of the active material deposited on the pole piece.
It comprises the following steps: the "fourth step" in example 1: essential characterization oriented to optimization technology and basic research: … … discharge capacity as a comparative data of the weight-to-capacity ratio of the active material deposited on the pole piece, the data obtained are listed in Table 1 in the row corresponding to example 1 "and replaced by" in the row corresponding to example 7 "in Table 1".
The rest is the same as example 1.
Table 1 weight specific capacity data for deposited active materials of each example
Figure GDA0003722476170000241
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: it is to be understood that modifications may be made to the technical solutions described in the foregoing embodiments, or equivalents may be substituted for some of the technical features thereof, but such modifications or substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (4)

1. A method for fused salt electrodeposition of active materials on a battery current collector is characterized in that: the method comprises the following three steps:
firstly, designing and constructing an electrodeposition tank;
the designed electrodeposition tank is cylindrical, the structural-functional integrated material for constructing the wall of the electrodeposition tank is mainly compact graphite, and the wall of the electrodeposition tank is used as a receptor of electrolyte and also used as a part of inert anode; the other two anodes are consumable anodes which are made of metal or alloy and are respectively arranged at the bottom of the electrodeposition tank and the upper part of the electrodeposition tank, and the product in the consumable anode consumption process is a chemical element required by the synthesis of the battery active substance; the cathode of the electrodeposition tank is arranged on the central axis of the cylindrical electrodeposition tank, and the electrolyte contained in the electrodeposition tank is chloride fused salt in the mixed halogen salt;
secondly, drying and preparing materials of the electrodeposition bath;
firstly, the temperature of the drying groove is 200 ℃ and the time is 4 hours;
secondly, the electrolyte formula in the preparation of the materials is as follows: 51 wt.% KCl-43 wt.% LiCl-1 wt.% MgCl 2 –5wt.％LaCl 3 Or 51 wt.% KCl-43 wt.% LiCl-2 wt.% MgCl 2 –4wt.％LaCl 3 Or 54 wt.% KCl-45 wt.% LiCl-1 wt.% LaCl 3 ；
The formula of the consumable anode powder molding material in the preparation of the materials is as follows: 3.3 wt.% Mg-0.7 wt.% Ni-96 wt.% AB 5 Type hydrogen storage alloy or 3 wt.% Mg-1 wt.% Ni-96 wt.% AB 5 Type hydrogen storage alloy or 78 wt.% Cu-16 wt.% Fe-6 wt.% AB 5 A hydrogen storage alloy of type;
fourthly, the consumable anode sheet stock in the prepared material is as follows: nickel flakes having a thickness of 0.5mm and a purity of 99.8 wt.% or commercially available nickel flakes having a thickness of 1mmNO. Sn 90 Sb 10 In the solder sheet of Sn-Sb alloy of (1), wherein Sn 90 Sb 10 Tin antimony alloy solder sheets are commercially available in a model representing an alloy composition of 90 wt.% Sn to 10 wt.% Sb;
fifthly, the consumable anode bar stock in the stock preparation is as follows: a nickel metal rod having a diameter of 10mm and a purity of 99.8 wt.% or a tin-antimony alloy rod having a diameter of 10mm and an alloy composition of 47.5 wt.% Sn-52.5 wt.% Sb;
sixthly, the cathode carrier material to be deposited in the stock preparation comprises the following components: commercially available foamed nickel or commercially available nickel plated steel strip or commercially available stainless steel mesh;
step three, the loading of the electro-deposition tank and the carrier are deposited and selectively annealed;
the method comprises the following steps of: respectively placing the cut consumable anode sheet material and the consumable anode bar material into the bottom and upper designated positions of the electrodeposition tank at room temperature, and then heating the outside of the electrodeposition tank, wherein the external heating temperature is controlled at 375 ℃, 380 ℃ or 400 ℃; adding the solid fragments of the electrolyte which are melted and prepared according to the formula into the electrodeposition tank one by one, continuously melting the electrolyte into liquid along with the solid, and stopping adding the electrolyte when the liquid level just submerges the annular consumable anode bar in the electrodeposition tank; then, feeding prepared consumable anode powder molding materials into the electrodeposition tank, wherein the feeding amount of the molding materials is 10 times of the weight of the prepared deposited anode carrier materials; then, hoisting the deposited cathode carrier material, inserting a temperature thermocouple probe and adjusting the stable electrodeposition temperature to prepare for the next electrodeposition;
the electrodeposition temperature of the carrier of the electrodeposition bath is 400 +/-2 ℃ or 380 +/-2 ℃ or 375 +/-2 ℃; the electrodeposition time is 10 minutes or 15 minutes;
and the selective annealing refers to two choices of annealing or non-annealing according to the physicochemical characteristics of the active substance deposited on the current collector of the battery and the use characteristics in the battery, wherein the current collector of the deposited active substance for the cathode of the nickel-metal hydride battery is selectively annealed at the annealing temperature of 500 ℃ for 1 hour, is cooled to 260 ℃ and is kept at the constant temperature for 2 hours, and the annealing protective atmosphere is argon.
2. The method of molten salt electrodeposition of an active material on a current collector of a battery according to claim 1, wherein: the feeding sequence of the salt raw materials used in the electrolyte in the prepared material to the furnace with the temperature of 790 ℃ is that the salt raw materials used in the electrolyte formula in the prepared material are fed to the furnace with the temperature of 790 ℃ according to the following sequence: anhydrous potassium chloride → anhydrous lithium chloride → anhydrous magnesium chloride → anhydrous lanthanum chloride.
3. The method of molten salt electrodeposition of an active material on a current collector of a battery according to claim 1, wherein: the granularity and the corresponding purity of the powder raw materials used in the formula of the consumable anode powder forming material in the prepared materials are respectively as follows: the average particle size of the metal magnesium powder is 100 meshes, and the purity of the metal magnesium powder is chemical purity; the metallic nickel powder is commercially available carbonyl nickel powder, the particle size of the carbonyl nickel powder is 800 meshes to 980 meshes, and the purity of the carbonyl nickel powder is 99 wt.%; AB 5 The powder of the type hydrogen absorbing alloy had a particle size of 200 mesh. + -. 50 mesh and a purity of 99.8 wt.%.
4. A method of molten salt electrodeposition of active species on a battery current collector as claimed in claim 1, wherein: the commercial specifications of the support materials used in the preparation of the negative electrode support material to be deposited are as follows: the surface density of the foamed nickel is 250g/m 2 ±20g/m 2 (ii) a The thickness of the nickel-plated steel strip is 0.2 mm; the stainless steel screen mesh is 200 meshes.
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