CN115911347A

CN115911347A - Porous self-supporting material, electrode, preparation method of porous self-supporting material and electrode, and battery

Info

Publication number: CN115911347A
Application number: CN202211484904.7A
Authority: CN
Inventors: 董锐锋; 熊宇; 胡玉霞; 夏大伟; 赵光金; 张少锋
Original assignee: State Grid Corp of China SGCC; Wuhan University WHU; Electric Power Research Institute of State Grid Henan Electric Power Co Ltd
Current assignee: State Grid Corp of China SGCC; Wuhan University WHU; Electric Power Research Institute of State Grid Henan Electric Power Co Ltd
Priority date: 2022-11-24
Filing date: 2022-11-24
Publication date: 2023-04-04

Abstract

The invention provides a porous self-supporting electrode material for a zinc battery, a preparation method and application thereof, wherein the porous self-supporting electrode material is a porous iron-nickel alloy, and the surface layer is a porous self-supporting alloy with less iron and rich nickel; the preparation method comprises the following steps: in a high-temperature molten salt system, a compact iron-nickel alloy is used as a working electrode, nickel is used as a counter electrode, silver-silver chloride is used as a reference electrode, and the anode is oxidized for 10-60 minutes at a potential of-0.5 to-0.2V to obtain the porous self-supporting iron-nickel alloy electrode. When the porous self-supporting iron-nickel alloy electrode is used for loading zinc, the porous self-supporting iron-nickel alloy electrode can be used in an aqueous zinc battery or a non-aqueous zinc battery. The invention can effectively solve the problem of zinc dendrite and has excellent cycle stability.

Description

Porous self-supporting material, electrode, preparation method of porous self-supporting material and electrode, and battery

Technical Field

The application belongs to the technical field of zinc batteries, and particularly relates to a porous self-supporting material and a preparation method thereof, an electrode material for a zinc battery, a preparation method and a battery.

Background

The zinc battery is concerned because the metal zinc cathode has the advantages of high theoretical capacity, good safety, low cost, easy processing, low toxicity and the like. At present, zinc-based batteries, including aqueous zinc-based batteries and non-aqueous zinc-based batteries, mainly use metallic zinc (Zn) as a negative electrode material. However, the metallic zinc negative electrode is not only liable to form zinc dendrites to pierce a battery separator to cause short-circuiting of the battery during long-term dissolution-deposition, but also liable to lose adhesion of excessively deposited zinc to cause material loss, thereby reducing the cycle life of the battery. Therefore, the cycle performance of the zinc negative electrode has been a key to restrict the practical use of zinc batteries.

In order to improve the stability of zinc anodes, researchers have made many attempts such as electrolyte optimization, zinc surface modification, development of embedded anodes to replace zinc metal anodes. Among them, zn surface modification is one of the most common strategies to modify Zn deposition behavior, mainly including surface Solid Electrolyte Interphase (SEI) construction, surface coating, and application of porous Zn. For example, zinc-based montmorillonite has been used as an artificial SEI to suppress the formation of zinc dendrites, but due to the low ionic conductivity and Zn ion transport number of the artificial SEI layer, the boundary with Zn isThe surface contact is poor, resulting in a low coulombic efficiency of Zn. Carbon-coated zinc (zn @ c) anodes have been developed to inhibit the formation of zinc dendrites. The porous carbon film can be used as a deposition site of zinc, so that the deposition site of zinc is changed into a hole on the carbon film from a hot spot on the exposed zinc film, but the behavior of the porous carbon film is greatly influenced by the thickness of the carbon film. Similarly, one tests the electrochemical behavior of the porous copper foam as a zinc host by electroplating zinc on the surface of the porous copper foam, and finds that the electrochemical behavior is small in voltage lag and high in coulomb efficiency, but the zinc cathode loaded by the porous copper foam has poor cycle performance and the current density is 1 mA-cm ^-2 In the case of (2), short circuits occurred after only 150 hours, which may be related to uneven zinc deposition caused by uneven pore size and distribution in the copper foam. Therefore, there is a need to develop zinc carriers with higher mechanical strength, appropriate pore size and high coulombic efficiency.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: in order to overcome the performance defect of the foam copper as a zinc host in the prior art, the porous self-supporting material and the preparation method thereof, and the electrode and the preparation method thereof are provided.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a porous self-supporting material is made of iron-nickel alloy. The expression of the material is Fe _x Ni _y Wherein x and y respectively represent the mass fractions of Fe and Ni in the alloy, and the value range of x is more than or equal to 10 and less than or equal to 80; y is within the range of 20-90;

the surface layer of the porous self-supporting material is of a porous structure, and the interior of the porous self-supporting material is of a solid structure. The porous layer of the material has a thickness of between 5 and 30um, and is an iron-poor nickel-rich layer.

Preferably, the value range of x is more than or equal to 10 and less than or equal to 30; the value range of y is more than or equal to 70 and less than or equal to 90.

The invention also provides a preparation method of the porous self-supporting material, which comprises the following steps: in a high-temperature molten salt system at 400-600 ℃, taking compact iron-nickel alloy as an anode, nickel as a cathode and silver-silver chloride as a reference electrode, and anodizing for 10-60 minutes at a potential of-0.5 to-0.2V to obtain the porous self-supporting iron-nickel alloy electrode.

Preferably, the high temperature molten salt temperature is selected to be 550 ℃.

Preferably, the oxidation potential of the iron and nickel is between-0.4 and-0.3V, and the anodic oxidation time is 30-60 minutes.

The invention also provides an application of the porous self-supporting material, and the porous self-supporting material is compounded with zinc and then used in an aqueous zinc ion battery or a non-aqueous zinc ion battery.

The invention also provides a preparation method of the electrode compounded by the porous self-supporting material and zinc, which comprises the following steps: in an inert atmosphere, rapidly melting zinc in an induction heating furnace by adopting an induction heating mode, vertically inserting the porous self-supporting iron-nickel alloy into a zinc melt for soaking for 10-60 seconds, vertically lifting the porous self-supporting iron-nickel alloy out of the zinc melt, and naturally cooling to obtain the electrode for the zinc battery.

The invention also provides a preparation method of the electrode, which comprises the following steps: the porous self-supporting material is subjected to electrogalvanizing to obtain an electrode for a zinc battery.

It is still another object of the present invention to provide a zinc-based battery, the negative electrode of which is a zinc electrode prepared by compounding the porous self-supporting material and zinc as described above.

The invention has the beneficial effects that:

1) The porous self-supporting material prepared by the invention has developed pores, smaller pore diameter, uniform distribution and controllable pore degree. The porous self-supporting material prepared by the invention has the average pore diameter of 0.23 mu m, is uniformly distributed and is distributed in the range of 0.16 to 0.45 mu m. (conventional porous self-supporting electrodes, including copper foam and nickel foam, have an average pore diameter of 290 μm, are unevenly distributed and are distributed at 80-370 μm.) the pore depth can be controlled by the composition of the original iron-nickel alloy, the electrochemical anodic oxidation time control, the oxidation potential and the oxidation temperature.

2) The electrode compounded by the porous self-supporting material and the zinc can be prepared simply and quickly. The obtained electrode has very uniform zinc distribution and can be uniformly filled into a porous structure.

3) The electrode compounded by the porous self-supporting material and the zinc has the outstanding electrochemical properties: firstly, the stripping/electroplating coulomb efficiency of the composite electrode is as high as 98.8%; secondly, at 0.5mA cm ^-2 Stable cycling at a temperature of more than 700 hours without dendrite formation;

4) When the porous self-supporting material is used as a composite zinc cathode and applied to a zinc ion battery, the formation of zinc dendrites can be effectively avoided, and the long-cycle advantage of the zinc cathode is exerted. For example, when the composite zinc cathode is matched with an iodine cathode to construct a zinc ion battery, the battery can be cycled for 5000 times. (when a conventional zinc cathode or a zinc cathode taking foamed nickel as a carrier is matched with an iodine cathode to construct a zinc ion battery, the battery can only be cycled for less than 900 times and short circuit failure occurs.)

Drawings

The technical solution of the present application is further explained below with reference to the drawings and the embodiments.

FIG. 1 is a SEM image of the front side of a porous self-supporting alloy prepared in example 1 of the present invention;

FIG. 2 is a SEM image of a cross-section of a porous self-supporting alloy prepared in example 1 of the present invention;

FIG. 3 is a graph of an energy spectrum of a porous self-supporting alloy prepared in example 1 of the present invention;

FIG. 4 is an SEM photograph of a porous self-supporting alloy prepared in example 2 of the present invention;

FIG. 5 is an SEM photograph of a porous self-supporting alloy prepared in example 3 of the present invention;

FIG. 6 is an SEM photograph of a porous self-supporting alloy prepared in example 4 of the present invention;

FIG. 7 is an SEM photograph of a commercial nickel foam produced in comparative example 5;

FIG. 8 is an SEM picture of a porous self-supporting alloy supported zinc electrode prepared in example 1 of the present invention;

FIG. 9 is an optical photograph of porous self-supporting alloy, nickel foam, metallic zinc during zinc deposition;

fig. 10 shows coulombic efficiencies of zinc electrodes supported by porous self-supporting alloy, zinc electrodes supported by foamed nickel and zinc metal in a half cell;

FIG. 11 shows the cycling stability of zinc electrodes supported on porous self-supporting alloy, zinc electrodes supported on foamed nickel, and zinc metal in a symmetrical cell;

FIG. 12 shows the cycle performance of zinc electrode supported by porous self-supporting alloy, zinc electrode supported by foamed nickel and metallic zinc in a full cell;

fig. 13 is an SEM photograph of porous self-supporting alloy supported zinc electrode, foamed nickel supported zinc electrode, metallic zinc after cycling in a full cell.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

In the description of the present application, it is to be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in the orientation or positional relationship indicated in the drawings for convenience in describing the present application and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated in a particular manner, and are not to be considered limiting of the scope of the present application. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the invention, the meaning of "a plurality" is two or more unless otherwise specified.

In the description of the present application, it should be noted that, unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, a fixed connection, a detachable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art through specific situations. In the present embodiment, the X, Y and Z directions or the X, Y and Z axes are all based on a cartesian coordinate system.

The technical solutions of the present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

Example 1

In a 550 ℃ LiCl-KCl (molar ratio 58.5 ₆₄ Ni ₃₆ The foil (Fe: ni mass ratio: 64wt%:36wt%,10 mm. Times.10 mm. Times.1 mm) was used as the working electrode, the Ni plate was the counter electrode, and Ag/AgCl was the reference electrode. Mixing Fe ₆₄ Ni ₃₆ The alloy working electrode was anodized at-0.3V (vs. Ag/AgCl) for 30min. And after the electrolysis is finished, washing the obtained working electrode with clear water, and drying in a vacuum oven at 60 ℃ to obtain the porous self-supporting alloy electrode. The SEM image of the front surface of the resulting porous self-supporting alloy electrode is shown in fig. 1. Figure 1 shows that the resulting working electrode is a self-supporting porous electrode. The cross-sectional SEM photograph of the resulting porous self-supporting alloy electrode is shown in fig. 2. FIG. 2 shows that the resulting porous layer reached a thickness of 10.20 μm. The spectral photograph of the resulting porous self-supporting alloy electrode is shown in FIG. 3. Fig. 3 shows that the iron content in the surface layer of the obtained working electrode is obviously reduced, and the working electrode is an alloy with less iron and more nickel.

Example 2

In a LiCl-KCl (molar ratio of 58.5 ₆₄ Ni ₃₆ The foil (Fe: ni mass ratio: 64wt%:36wt%,10 mm. Times.10 mm. Times.1 mm) was used as the working electrode, the Ni plate was the counter electrode, and Ag/AgCl was the reference electrode. Mixing Fe ₆₄ Ni ₃₆ The alloy working electrode was anodized at-0.3V (vs. Ag/AgCl) for 10min. And after the electrolysis is finished, washing the obtained working electrode with clear water, and drying in a vacuum oven at 60 ℃ to obtain the porous self-supporting alloy electrode. The SEM image of the front surface of the resulting porous self-supporting alloy electrode is shown in fig. 4. Figure 4 shows that the resulting working electrode is a self-supporting porous electrode.

Example 3

In a LiCl-KCl (molar ratio of 58.5 ₆₄ Ni ₃₆ The foil (Fe: ni mass ratio: 64wt%:36wt%,10 mm. Times.10 mm. Times.1 mm) was used as the working electrode, the Ni plate was the counter electrode, and Ag/AgCl was the reference electrode. Mixing Fe ₆₄ Ni ₃₆ The alloy working electrode was anodized at-0.3V (vs. Ag/AgCl) for 60min. And after the electrolysis is finished, washing the obtained working electrode with clear water, and drying in a vacuum oven at 60 ℃ to obtain the porous self-supporting alloy electrode. The SEM image of the front surface of the resulting porous self-supporting alloy electrode is shown in fig. 5. Figure 5 shows that the resulting working electrode is a self-supporting porous electrode.

Example 4

In a LiCl-KCl (molar ratio of 58.5 ₅₀ Ni ₅₀ The foil (Fe to Ni mass ratio 50wt%:50wt%,10 mm. Times.10 mm. Times.1 mm) was the working electrode, the Ni plate was the counter electrode, and Ag/AgCl was the reference electrode. Mixing Fe ₅₀ Ni ₅₀ The alloy working electrode was anodized at-0.3V (vs. Ag/AgCl) for 30min. And after the electrolysis is finished, washing the obtained working electrode with clear water, and drying in a vacuum oven at 60 ℃ to obtain the porous self-supporting alloy electrode. The SEM image of the front surface of the resulting porous self-supporting alloy electrode is shown in fig. 6. Figure 6 shows that the resulting working electrode is a self-supporting porous electrode.

Comparative example 5

Fig. 7 is an SEM photograph of commercial nickel foam. Commercial nickel foam is porous, but the pores are large in size and are not uniformly distributed, as shown in fig. 7.

Example 6

20g of Zn pellets (99.999%) were weighed into a graphite crucible and heated to the melting point by an induction thermocouple in a glove box. The obtained porous self-supporting alloy in example 1 was vertically and rapidly immersed in molten Zn for about 15 seconds, and then vertically taken out of the molten Zn to be cooled to room temperature, to obtain a porous self-supporting alloy-supported zinc electrode as shown in fig. 8. As shown in fig. 8, the pore structure in the porous self-supporting alloy is uniformly filled with zinc.

Example 7

The optical photographs of the porous self-supporting alloy of example 1, the commercial nickel foam of example 5, and the commercial zinc metal in these structures at various time periods by observing the deposition process of zinc in situ are shown in fig. 9. As shown in fig. 9, it can be seen that zinc is prone to dendrite on pure zinc and foamed nickel deposits, but the formation of zinc dendrites is significantly suppressed when deposited in porous self-supporting alloys.

Example 8

The porous self-supporting alloy in example 1 and the nickel foam in example 5 were prepared into zinc electrodes with zinc supported on the porous self-supporting alloy and zinc supported on commercial nickel foam according to the method in example 6. Taking a zinc electrode with zinc loaded by porous self-supporting alloy and zinc loaded by commercial foam nickel, a pure zinc electrode as a counter electrode and a reference electrode, taking copper foil as a working electrode, and 3mol/L ZnSO ₄ The aqueous solution of (2) is used as an electrolyte to assemble a button cell, and the electrochemical performance of the button cell is tested, and the cycling stability is shown in figure 10. FIG. 10 shows that the current density was 1mA cm ^-2 The area capacity is 1mAh cm ^-2 In the case of (2), the electrode with the porous alloy loaded with zinc has higher coulombic efficiency and stability.

Example 9

The working electrode was replaced with a porous alloy loaded zinc, a commercial nickel foam loaded zinc, and a pure zinc sheet according to the methods of examples 7 and 8, and assembled into a symmetrical button cell, which was tested for electrochemical performance according to the test method of example 7, and cycling stability as shown in fig. 11. Figure 11 shows that the electrode with zinc supported on a porous alloy has better stability.

Example 10

The electrode with carbon-coated iodine is used as the anode, the porous alloy loaded zinc, the commercial foam nickel loaded zinc and the pure zinc sheet are respectively used as the cathode, and 3mol/L ZnSO is used ₄ The aqueous solution as electrolyte is assembled into button cell, and the electrochemical performance is tested, and the cycling stability is shown in figure 12. FIG. 12 shows that full cells constructed with electrodes loaded with zinc in porous alloys have better stability for 5000 cyclesAnd no short circuit.

Example 11

The porous alloy loaded with zinc, the commercial nickel foam loaded with zinc, and the pure zinc sheet electrode after the circulation in example 10 were observed for the change in morphology by SEM, and the results are shown in fig. 13. Fig. 13 shows that the porous alloy zinc-loaded electrode has small morphology change and can effectively inhibit the generation of dendrites.

The porous self-supporting alloy electrode suitable for use in the present invention is not limited to Fe as specified in the above examples _x Ni _y Several, may be ternary or multicomponent porous alloy. The method of supporting zinc on the porous alloy is not limited to the melting method, and may be a plating method.

In light of the foregoing description of the preferred embodiments according to the present application, it is to be understood that various changes and modifications may be made by those skilled in the art without departing from the scope of the invention as defined by the appended claims. The technical scope of the present application is not limited to the content of the specification, and must be determined according to the scope of the claims.

Claims

1. The porous self-supporting material is characterized by comprising an iron-nickel alloy, wherein the expression of the iron-nickel alloy is Fe _x Ni _y Wherein x and y respectively represent the mass fractions of Fe and Ni in the alloy, and the value range of x is more than or equal to 10 and less than or equal to 80; the value range of y is more than or equal to 20 and less than or equal to 90.

2. The porous self-supporting material according to claim 1, wherein the surface layer of the iron-nickel alloy material is a porous structure and the inside is a solid structure.

3. The porous self-supporting material of claim 2, wherein the porous layer of iron-nickel alloy material is between 5 and 30um thick and the porous layer is an iron-poor and nickel-rich layer.

4. The porous self-supporting material according to any one of claims 1 to 3, wherein x is in the range of 10. Ltoreq. X.ltoreq.30; the value range of y is more than or equal to 70 and less than or equal to 90.

5. A process for the preparation of a porous self-supporting material according to any one of claims 1 to 4, comprising the steps of:

and (3) carrying out anodic oxidation on the compact iron-nickel alloy as an anode, nickel as a cathode and silver-silver chloride as a reference electrode to obtain the porous self-supporting material.

6. The preparation method of claim 5, wherein the preparation method is characterized in that the oxidation potential between-0.5V and-0.2V is applied in a high-temperature molten salt system at 400-600 ℃, and the duration of anodic oxidation is 10-60 minutes.

7. An electrode prepared by compounding the porous self-supporting material according to any one of claims 1 to 4 with zinc.

8. A preparation method of an electrode is characterized by comprising the following steps: rapidly melting zinc by induction heating in an induction heating furnace under an inert atmosphere, then inserting the porous self-supporting material of any one of claims 1 to 4 into a zinc melt for soaking, then extracting the porous self-supporting material above the zinc melt, and naturally cooling to obtain the electrode for the zinc battery.

9. A preparation method of an electrode is characterized by comprising the following steps: an electrode for a zinc battery obtained by electrogalvanizing the porous self-supporting material according to any one of claims 1 to 4.

10. A battery, characterized in that the negative electrode of the battery employs the electrode according to claim 7.