WO2017186151A1

WO2017186151A1 - Zinc-air battery having equivalent three-electrode structure

Info

Publication number: WO2017186151A1
Application number: PCT/CN2017/082282
Authority: WO
Inventors: 裴普成; 王克亮; 王希忠
Original assignee: 清华大学
Priority date: 2016-04-29
Filing date: 2017-04-27
Publication date: 2017-11-02
Also published as: CN105789738A; CN105789738B

Abstract

Provided is a zinc-air battery having an equivalent three-electrode structure. The battery comprises: a body, in which a reaction space is defined; an air electrode, which is disposed inside the body, located above the reaction space, and in contact with air; a charging electrode, which is provided below the air electrode; and a zinc electrode, which is disposed inside the body and located below the charging electrode.

Description

Zinc-air battery with equivalent three-electrode structure

Priority information

Priority is claimed on Japanese Patent Application No. 201610282302.1, filed on Jan. 29,,,,,,,,,

Technical field

The present invention relates to the field of energy storage and power supply, and in particular to a zinc-air battery of an equivalent three-electrode structure, and more particularly to a zinc-air battery.

Background technique

A rechargeable zinc-air battery is an electrochemical energy storage device. During the charging and discharging process, the electrical energy and chemical energy on the electrode surface are mutually converted, thereby completing the charging-discharging process and realizing the storage and supply of electrical energy. The zinc-air battery has the advantages of high specific energy, good electrochemical reversibility, high safety, no pollution, and convenient carrying. Compared with other metal-air batteries, zinc-air batteries have technical, safety and cost advantages. There are two main types of current rechargeable zinc-air batteries. One type of battery has a three-electrode structure. The zinc-air battery has a zinc electrode, an air electrode, and a charging electrode. Zinc precipitation and dissolution (reduction/oxidation reaction) occurs on the surface of the zinc electrode. ), the charging electrode and the surface of the air electrode have corresponding oxidation and reduction reactions, the air electrode and the charging electrode are placed on both sides of the zinc electrode; the other zinc-air battery adopts a two-electrode structure, and the zinc electrode is used for precipitation of zinc and Dissolved, the other electrode has a redox bifunctional catalyst to achieve an oxidation reaction and a reduction reaction.

However, the electrode battery structure of current zinc-air batteries still needs to be improved.

Summary of the invention

This application is based on the discovery and recognition of the following facts and issues by the inventors:

At present, the rechargeable zinc-air battery generally has problems such as rapid charge and discharge, low battery charge and discharge current density, or short battery cycle life, and thus it is difficult to achieve widespread application. The inventors have found through in-depth research that this is mainly due to the current zinc-air battery. The zinc electrode surface needs to undergo zinc precipitation-dissolution process, so the surface morphology of the electrode changes greatly, and it is easy to cause zinc dendrite during use. Growing. The continued growth of zinc dendrites tends to damage other electrodes in the cell, eventually causing a short circuit in the cell. Therefore, when the three-electrode structure is adopted, the air electrode and the charging electrode need to be placed on both sides of the zinc electrode to alleviate the damage of the zinc dendrite to the air electrode and the charging electrode. However, this structure results in a battery that is not compact enough, resulting in a lower specific energy of the battery. A two-electrode system using a dual-function catalyst generates a large amount of bubbles (such as oxygen) under high current density charge and discharge conditions, thereby accelerating catalyst loss. Lead to air electrode failure, battery performance is rapidly attenuated; and high current density working conditions tend to accelerate zinc dendrite growth, thus resulting in batteries The cycle life is not high.

The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, an object of the present invention is to provide a zinc-air battery, which has an equivalent three-electrode structure by designing the electrode arrangement and the overall structure of the battery, thereby saving battery space and improving the battery space. The battery charge and discharge current density makes it ideal for battery life while having a higher current density.

Specifically, the present invention proposes a zinc-air battery. The battery includes: a body defining a reaction space in the body; an air electrode disposed inside the body, located above the reaction space and in contact with air; a charging electrode, the charging electrode being disposed at the Below the air electrode; and a zinc electrode disposed inside the body and below the charging electrode. The zinc-air battery has the air electrode and the charging electrode disposed on the same side of the zinc electrode to make the battery structure more compact. The design of each electrode in the battery and the overall structure of the battery are designed to effectively alleviate the zinc dendrite for the electrode during use. Damage caused, resulting in higher current density and better battery life.

According to an embodiment of the invention, the charging electrode is a metal mesh. Thereby, it is convenient for the electrolyte to pass through the charging electrode to contact the air electrode.

According to an embodiment of the invention, the metal mesh is capable of catalyzing an oxygen evolution reaction. Thereby, the electrode performance of the charging electrode can be further improved.

According to an embodiment of the present invention, the zinc-air battery further includes: a support frame, the air electrode and the charging electrode are respectively disposed on both sides of the support frame. Thereby, space can be further saved and the battery structure can be made more compact.

According to an embodiment of the invention, the support frame is made of a conductive material, and the air electrode and the charging electrode are electrically connected to the support frame, respectively. Thereby, the connection of the air electrode and the charging electrode to the external circuit can be easily realized by the support frame.

According to an embodiment of the invention, the air electrode and the charging electrode share the same contact, and one end of the support frame is the contact. Thereby, space can be further saved and the battery structure can be made more compact.

According to an embodiment of the present invention, the zinc-air battery further includes: an electrolyte inlet disposed on the body; an electrolyte outlet, the electrolyte outlet being disposed on the body; a reservoir, the reservoir The liquid pool stores an electrolyte; a conduit disposed between the electrolyte inlet and the reservoir, and between the electrolyte outlet and the reservoir; and a liquid transfer pump, the liquid transfer pump The conduits are connected. Thereby, the oxygen generated on the charging electrode can be led out in time by the conduit, and the body can be discharged together with the electrolyte, so that a large amount of bubbles can be avoided to wash the surface of the charging electrode and negatively affect the charging electrode.

According to an embodiment of the invention, the zinc electrode is composed of at least one of a carbon plate, a stainless steel plate, a zinc plate, and a porous conductive plate. Thereby, the performance of the battery can be further improved.

According to an embodiment of the invention, the reaction spaces have different cross sections at different positions in the vertical direction. Thus, The mass transfer of the fluid (electrolyte) in the bulk can be attenuated, thereby alleviating the growth of zinc dendrites.

According to an embodiment of the invention, the longitudinal section of the reaction space is trapezoidal, tower-shaped or irregularly shaped. Thereby, the mass transfer of the fluid (electrolyte) in the bulk can be further attenuated, thereby alleviating the growth of zinc dendrites.

According to an embodiment of the invention, the distance between the charging electrode and the zinc electrode is 5 to 10 mm. The proper distance is beneficial to avoid the short distance and cause the zinc dendrite to contact the charging electrode too quickly to cause short circuit of the battery, or the distance is too long, the internal resistance of the battery is large, the energy circulation efficiency is low, and the voltage difference between the charging and discharging processes is increased. Causes the growth of zinc dendrite to accelerate.

DRAWINGS

1 shows a schematic structural view of a zinc-air battery according to an embodiment of the present invention;

2 is a schematic view showing the structure of a zinc-air battery according to another embodiment of the present invention;

3 is a partial structural view showing a zinc-air battery according to still another embodiment of the present invention;

4 is a schematic structural view of a zinc-air battery according to still another embodiment of the present invention;

Figure 5 is a schematic view showing the structure of a zinc-air battery according to still another embodiment of the present invention;

6 is a schematic structural view of a zinc-air battery according to still another embodiment of the present invention;

Figure 7 is a block diagram showing the structure of a zinc-air battery according to still another embodiment of the present invention;

Figure 8 is a graph showing a charge/discharge test of a zinc-air battery according to Embodiment 1 of the present invention;

Figure 9 is a graph showing a charge/discharge test of a zinc-air battery according to Embodiment 2 of the present invention.

Description of the reference signs:

Body 100; air electrode 200; charging electrode 300; zinc electrode 400; support frame 500;

Electrolyte inlet 110; electrolyte outlet 120; conduit 20; reservoir 600; liquid delivery pump 30.

detailed description

The embodiments of the present invention are described in detail below, and the examples of the embodiments are illustrated in the drawings, wherein the same or similar reference numerals are used to refer to the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are intended to be illustrative of the invention and are not to be construed as limiting.

In the description of the present invention, it is to be understood that the orientation or positional relationship of the terms "upper", "lower" and the like is based on the orientation or positional relationship shown in the drawings, and is merely for convenience of description of the present invention and simplified description. Instead of indicating or implying that the device or component referred to must have a particular orientation, constructed and operated in a particular orientation, it is not to be construed as limiting the invention. In the present invention, the terms "upper" or "above", "upper surface" and the like of the structure of the zinc electrode, the air electrode, and the charging electrode indicate the side of the above structure which is close to the outside air and away from the internal electrolyte (electrolyte).

In one aspect of the invention, the invention provides a zinc-air battery. Referring to FIG. 1, the battery includes: a body 100. Air electrode 200, charging electrode 300, and zinc electrode 400. Specifically, a reaction space is defined in the body 100 so that the zinc electrode 400 and the charging electrode 300 undergo a corresponding redox reaction in the electrolyte. The air electrode 200 is disposed inside the body 100, is located above the reaction space and is in contact with air to cause a reduction reaction using oxygen in the air, and the charging electrode 300 is disposed under the air electrode 200. The zinc electrode 400 is disposed inside the body and under the charging electrode 300, that is, the charging electrode 300 and the air electrode 200 are located on the same side of the zinc electrode 400. By designing the above electrode and the overall structure of the zinc-air battery, the air electrode 200 and the charging electrode 300 can be disposed on the same side of the zinc electrode 400, so that the battery structure is more compact; the battery can effectively alleviate the zinc dendrite during use. For damage caused by the electrodes, it can work at higher current densities and achieve better battery life.

The structure of each part of the zinc-air battery will be described in detail below according to an embodiment of the present invention.

According to an embodiment of the present invention, the body 100 defines a reaction space for a zinc-air battery according to an embodiment of the present invention, and the specific material, shape, and arrangement thereof are not particularly limited. For example, an organic glass may be used as the body 100, and structures such as the air electrode 200, the charging electrode 300, and the zinc electrode 400 may be fixed therein by means of a positioning clip or the like, and a certain amount of electrolyte (such as an electrolyte) may be added inside the body 100. It will be understood by those skilled in the art that the above electrolyte may employ an alkaline or neutral aqueous electrolyte, and a paste electrolyte or an ionic liquid may also be used. The zinc electrode 400 may be composed of an electrode material commonly used in the art as long as the electrode material is chemically stable in a medium in which the zinc-air battery operates and a voltage range, and a zinc precipitation-dissolution process is performed thereon. For example, the zinc electrode 400 may be composed of at least one of a carbon plate, a stainless steel plate, a zinc plate, and a porous conductive plate. Thereby, the performance of the battery can be further improved. It can be understood by those skilled in the art that the porous conductive plate may be a plate electrode formed of a porous electrode material commonly used in the art, and those skilled in the art may select a suitable porous electrode material to form the zinc electrode 400 according to actual conditions. In the present invention, the specific type of the air electrode 200 is not particularly limited, and those skilled in the art can employ the familiar air electrode to constitute the air electrode 200 according to an embodiment of the present invention.

According to an embodiment of the invention, the charging electrode 300 may be a metal mesh. Thereby, the effective electrode area of the charging electrode 300 can be effectively increased, and according to an embodiment of the present invention, the metal mesh can have a function of catalyzing an oxygen evolution reaction. For example, the metal oxygen evolution reaction catalyst can be formed into a network structure as the charging electrode 300 of the present invention. For example, the metal mesh may contain a transition metal element. Specifically, the above metal mesh may be a nickel mesh or a foamed nickel mesh. Thereby, the efficiency and effect of the oxidation reaction on the surface of the charging electrode 300 can be improved by using the above-described metal mesh having a catalytic function. The charging electrode 300 having the above structure can realize its electrode function without supporting a catalyst, thereby saving production cost, simplifying the production process, and the charging electrode 300 not supporting the catalyst is not operated under a large current density condition. A large amount of bubbles (precipitated oxygen) wash the surface of the electrode, causing catalyst loss and affecting electrode performance. The electrode of the charging electrode 300 according to the embodiment of the present invention has stable performance, so that the zinc-air electrode can be operated under a large current density condition and has a desirable battery life.

The overall performance and life of a zinc-air battery is not only related to the material and arrangement of the various components of the battery, the battery The overall arrangement also has an important impact on the above performance of the battery. In order to further improve the performance of the zinc-air battery according to an embodiment of the present invention, according to an embodiment of the present invention, referring to FIG. 2, the distance D between the charging electrode 300 and the zinc electrode 400 may be 5 to 10 mm. The inventors have found through a large number of experiments that the distance between the charging electrode 300 and the zinc electrode 400 is too close, which tends to cause the zinc dendrite to contact the charging electrode too quickly, causing the battery to be short-circuited; the distance between the charging electrode 300 and the zinc electrode 400 is too far. It will increase the internal resistance of the battery, causing the difference between the charging voltage and the discharging voltage of the battery to increase, not only reducing the energy circulation efficiency, but also accelerating the rapid growth of zinc dendrites, resulting in short circuit of the battery and shortening the cycle life of the zinc-air battery. Setting the distance between the charging electrode 300 and the zinc electrode 400 within the above range can alleviate or avoid the above problem.

According to an embodiment of the invention, referring to FIG. 2, the zinc-air battery further includes a support frame 500. The air electrode 200 and the charging electrode 300 are respectively disposed on both sides of the support frame 500. Thereby, space can be further saved and the battery structure can be made more compact. According to an embodiment of the present invention, the support frame 500 may be composed of a conductive material, and the air electrode 200 and the charging electrode 300 are electrically connected to the support frame, respectively. Thereby, the connection of the air electrode and the charging electrode to the external circuit can be easily realized by the support frame. For example, according to a specific embodiment of the present invention, the air electrode 200 and the charging electrode 300 may be fixed on both sides of the support frame 500 by welding or the like, and one end of the support frame 500 is used as air by the conductive property of the support frame 500 itself. The contact 10 shared by the electrode 200 and the charging electrode 300 can further save space and make the battery structure more compact. For example, a stainless steel frame or a stainless steel mesh can be simply used as the support frame 500. It will be understood by those skilled in the art that since the air electrode 200 and the charging electrode 300 need to contact the electrolyte in order to function as an electrode, the arrangement of the support frame 500 should not block the contact between the electrolyte and the air electrode 200 and the charging electrode 300.

According to an embodiment of the present invention, in order to further improve the performance of the zinc-air battery, referring to FIG. 3, the zinc-air battery may further include: an electrolyte inlet 110, an electrolyte outlet 120, a conduit 20, a liquid transfer pump 30, and a liquid storage solution. Pool 600. Specifically, the electrolyte inlet 110 and the electrolyte outlet 120 are respectively disposed on the body 100 and connected to the reservoir 600 through the conduit 20, that is, the conduit 20 is disposed between the electrolyte inlet 110 and the reservoir 600, and the electrolyte. The outlet 120 is between the reservoir 600. An electrolyte is stored in the reservoir 600, and the liquid delivery pump 30 is used to supply the electrolyte and adjust the flow rate of the electrolyte supply. Specifically, the electrolyte in the reservoir 600 is supplied to the reaction space defined by the body 100 through the conduit 20 through the conduit 20, and is discharged from the reaction outlet by the electrolyte outlet 120, and returned to the reservoir 600 through the conduit 20. Thereby, the circulation of the electrolyte can be configured by the above structure, and the gas (oxygen) generated on the surface of the charging electrode 300 can be discharged into the body 100 in time, thereby preventing a large amount of gas from scouring the charging electrode 300 and the air electrode 200, thereby causing damage to the electrode structure, thereby The battery is more suitable for charging and discharging under high current conditions.

After extensive experiments and in-depth research, the inventors found that the mass transfer of electrolytes in the reaction space has an important influence on the growth of zinc dendrites. Specifically, when the mass transfer of the electrolyte between the charging electrode 300 and the zinc electrode 400 is not hindered, the growth of the zinc dendrites is facilitated. Therefore, in order to further improve the performance of the zinc-air battery, according to an embodiment of the present invention, Referring to FIGS. 4 to 7, the cross sections of the reaction spaces at different positions in the vertical direction may be different. That is to say, the shape or area of the cross section of the body 100 is different at different positions in the vertical direction of the reaction space. In other words, the body 100 may not be a cube or a cuboid. Thereby, the mass transfer of the fluid (electrolyte) in the bulk can be weakened, thereby alleviating the growth of zinc dendrites. Specifically, the longitudinal section of the reaction space may be trapezoidal (as shown in FIG. 4), tower type (as shown in FIGS. 5 to 7), or irregular polygons. It will be understood by those skilled in the art that the trapezoidal, tower or irregular polygons described above should be understood in a broad sense, either as a positive trapezoid in a narrow sense or as an inverted trapezoid as shown in FIG. The tower type or the irregular polygon involved in the present invention is the same as the trapezoidal case. Thereby, the mass transfer of the fluid (electrolyte) in the bulk can be further attenuated, thereby alleviating the growth of zinc dendrites.

It should be noted that the improvement of the structure of the above zinc-air battery is also within the scope of the present invention without any creative labor. For example, referring to FIG. 7 , the body 100 may be formed by using the organic glass, and the organic glass may have a certain shape by cutting, so that the longitudinal section of the reaction space defined by the body 100 made of the organic glass is set to a tower shape; or One end of the zinc electrode 400 may be disposed outside the body 100, and one end of the exterior of the body 100 may be used as a contact for connecting the zinc electrode 400 to an external circuit by the conductivity of the zinc electrode 400 itself. Similarly, when the air electrode 200 and the charging electrode 300 share one contact 10 (ie, one end of the support frame 500), the contact 10 can also be disposed outside the body 100 to conveniently complete the air electrode 200 and the charging electrode. 300 connection to the external circuit. At this time, when the zinc-air battery needs to be charged, the zinc electrode 400 and the surface of the charging electrode 300 can be redoxed by simply connecting the contact 10 and the portion of the zinc electrode 400 outside the body to an external power source. The reaction converts electrical energy into chemical energy for storage; when the zinc-air battery needs to be used for energy supply, only the contact 10 and the zinc electrode 400 are located outside the body and the load (resistance or electrical device requiring energy supply) , circuit and other components can be connected.

The invention is illustrated by the following specific examples. The following specific examples are intended to be illustrative only and not to limit the scope of the invention in any way, and unless otherwise specified, The conditions or steps are all conventional and the reagents and materials employed are commercially available.

Example 1

The air electrode is formed by nickel-iron catalyst and carbon powder hot-pressed on the foamed nickel. The nickel mesh is used as a charging electrode, the stainless steel frame is used as a support frame, and the air electrode and the charging electrode are welded on the stainless steel frame to make the electrolyte pass through the nickel. The mesh is in contact with the air electrode, and the air electrode and the charging electrode share one end of the stainless steel frame as a contact to be connected to an external power source or a load. The zinc electrode is a stainless steel plate. The zinc electrode, the air electrode, and the charging electrode were cut to a size of 30 mm × 30 mm. The reaction space is a rectangular parallelepiped, the distance between the charging electrode and the zinc electrode is 5 mm, and the electrolytic solution is an aqueous solution containing KOH and ZnO, wherein the KOH concentration is 7 mol/L, and the ZnO concentration is 0.6 mol/L.

Referring to Fig. 8, the zinc-air battery was cycled with a charge and discharge function at a current density of 50 mA/cm ² , a charging voltage of 2.2 V, and a discharge voltage of 1 V. The electrolyte flow rate (υ) was adjusted by a liquid transfer pump, and the zinc-air battery was operated at a large current density of 50 mA/cm ² at a flow rate of 10 mL/min and a flow rate of 50 mL/min. The zinc-air battery has a greater cycle life at a flow rate of 50 mL/min. The above current density is greatly improved compared to the zinc-air battery of the conventional three-electrode system.

Example 2

The rest of the structure of the zinc-air battery is the same as that of the first embodiment, except that the electrolyte tank structure is in the form of a tower, and the distance between the charging electrode and the zinc electrode is 8 mm.

Referring to Fig. 9, the zinc-air battery can be continuously operated for 100 hours at a current density of 50 mA/cm ² (electrolyte flow rate of 50 mL/min), and the battery life is ideal. This structure can delay the growth of dendrites and effectively extend the life of zinc-air batteries.

In the description of the present specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means a specific feature described in connection with the embodiment or example. A structure, material or feature is included in at least one embodiment or example of the invention. In the present specification, the schematic representation of the above terms is not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, various embodiments or examples described in the specification, as well as features of various embodiments or examples, may be combined and combined.

Although the embodiments of the present invention have been shown and described, it is understood that the above-described embodiments are illustrative and are not to be construed as limiting the scope of the invention. The embodiments are subject to variations, modifications, substitutions and variations.

Claims

A zinc-air battery, comprising:

a body defining a reaction space in the body;

An air electrode disposed inside the body, above the reaction space and in contact with air;

a charging electrode, the charging electrode being disposed under the air electrode;

A zinc electrode disposed inside the body and under the charging electrode.
The zinc-air battery according to claim 1, wherein the charging electrode is a metal mesh.
The zinc-air battery according to claim 2, wherein said metal mesh is capable of catalyzing an oxygen evolution reaction.
The zinc-air battery according to claim 1, further comprising:

A support frame, the air electrode and the charging electrode are respectively disposed on both sides of the support frame.
The zinc-air battery according to claim 4, wherein said support frame is made of a conductive material, and said air electrode and said charge electrode are electrically connected to said support frame, respectively.
The zinc-air battery according to claim 5, wherein the air electrode and the charging electrode share the same contact, and one end of the support frame is the contact.
The zinc-air battery according to claim 1, further comprising:

An electrolyte inlet, the electrolyte inlet being disposed on the body;

An electrolyte outlet, the electrolyte outlet being disposed on the body;

a liquid storage tank storing an electrolyte;

a conduit disposed between the electrolyte inlet and the reservoir, and between the electrolyte outlet and the reservoir;

A liquid delivery pump connected to the conduit.
The zinc-air battery according to claim 1, wherein the zinc electrode is composed of at least one of a carbon plate, a stainless steel plate, a zinc plate, and a porous conductive plate.
The zinc-air battery according to claim 1, wherein the reaction spaces have different cross sections at different positions in the vertical direction.
The zinc-air battery according to claim 1, wherein the reaction space has a longitudinal section of a trapezoid, a tower or an irregular polygon.
The zinc-air battery according to claim 1, wherein a distance between the charging electrode and the zinc electrode is 5 to 10 mm.