CN116315317A

CN116315317A - Zinc-air battery and preparation method thereof

Info

Publication number: CN116315317A
Application number: CN202310259150.3A
Authority: CN
Inventors: 牛凤娟; 冯健; 张莹莹
Original assignee: Yingkou Institute of Technology
Current assignee: Yingkou Institute of Technology
Priority date: 2023-03-17
Filing date: 2023-03-17
Publication date: 2023-06-23

Abstract

The invention discloses a zinc-air battery and a preparation method thereof. The invention provides a zinc-air battery and a preparation method thereof, wherein the zinc-air battery is provided with: a negative electrode, a positive electrode and an electrolyte, wherein the negative electrode is metallic zinc, the positive electrode is an air electrode formed by a carbon-based layer containing a catalyst, and the electrolyte is a nonaqueous electrolyte; the negative electrode and the positive electrode are separated by a diaphragm; the electrolyte is solid polymer electrolyte or room temperature ionic liquid electrolyte, and the non-aqueous electrolyte is adopted to prepare the zinc-air battery, so that the problems of electrode corrosion, dendrite formation, electrolyte drying, leaching and the like can be eliminated.

Description

Zinc-air battery and preparation method thereof

Technical Field

The invention relates to the technical field of zinc-air batteries, in particular to a zinc-air battery and a preparation method thereof.

Background

Zinc-air batteries, which are the most promising electrical energy storage, are becoming increasingly important in addressing future energy demands due to their simple structure, high specific energy density (about 1084 Wh/kg), and lack of environmental pollution. Zinc-air batteries have since their birth employed aqueous electrolytes, primarily alkaline electrolytes. Potassium hydroxide is currently the most commonly used alkaline electrolyte and has the advantages of high conductivity, high activity on zinc electrodes and air electrodes, good low-temperature performance and the like. Because the cathode is exposed to air, evaporation of water is unavoidable, which can lead to drying of the electrolyte over time, ultimately shortening the battery life. Among aqueous electrolytes, acidic electrolytes including inorganic acids (such as sulfurous acid) and organic acids (such as methanesulfonic acid, polyvinylalcohol sulfonic acid, and polyvinylalcohol sulfuric acid) have been proposed and zinc-air batteries have been developed. However, in most acidic electrolytes, the zinc metal in the anode is not stable and there is a serious corrosion problem. Therefore, the use of an acidic electrolyte is not preferable in practical applications. There are still more or less problems in zinc air battery systems today with the widely used alkaline aqueous electrolytes. Therefore, there is a need for a zinc-air battery and a method for manufacturing the same to solve the above-mentioned problems.

Disclosure of Invention

The invention aims to provide a zinc-air battery and a preparation method thereof, which are used for solving the problems caused by the adoption of water electrolyte in the existing zinc-air battery.

The invention provides a zinc-air battery, comprising: a negative electrode, a positive electrode and an electrolyte, wherein the negative electrode is metallic zinc, the positive electrode is an air electrode formed by a carbon-based layer containing a catalyst, and the electrolyte is a nonaqueous electrolyte; the negative electrode and the positive electrode are separated by a diaphragm; the electrolyte is a solid polymer electrolyte or a room temperature ionic liquid electrolyte.

Optionally, the membrane adopts an anion exchange coating with a microphase separation structure obtained by copolymerizing an ionic monomer containing OH & lt- & gt and butyl methacrylate in a solvent.

Optionally, the membrane is prepared by adopting a dry method, a polymer matrix is melted at high temperature, a sheet structure is extruded under the action of pressure, the sheet structure is converted from a viscous state to a high-elastic state through thermal annealing, then the sheet structure with regular arrangement is formed through stretching, and finally the stretching pore forming is carried out.

Optionally, the membrane is prepared by a wet method, the polyolefin resin, the plasticizer and the high-boiling point low-molecular pore-forming agent are mixed into a homogeneous system, the homogeneous system is extruded under the action of high temperature and pressure and is rapidly cooled, and at the moment, the membrane is subjected to phase separation, but the pore-forming agent is still remained on the membrane; and (3) performing biaxial stretching to continuously expand the existing pores, and extracting the micromolecular pore-forming agent by using an organic volatile solvent to generate micropores.

Optionally, the separator is made by a nonwoven technique, where the various fibers are first laid in a random pattern and then physically and chemically consolidated, or where special binder fibers are used to enhance mechanical properties.

Optionally, the membrane is prepared by a solution casting method, polymer solutes are dissolved in volatile solvents, after the solutions are uniformly mixed, the membrane is coated on a smooth glass plate or other planes to form a membrane, and then the membrane is placed in solvents which are mutually soluble with the solvents but are insoluble in the membrane body or is directly dried, and the membrane with certain pores is obtained through volatilization or dissolution of the solvents.

The invention also provides a preparation method of the zinc-air battery, and the zinc-air battery adopts any one of the zinc-air batteries.

The beneficial effects of the invention are as follows: the invention provides a zinc-air battery and a preparation method thereof, wherein the zinc-air battery is provided with: a negative electrode, a positive electrode and an electrolyte, wherein the negative electrode is metallic zinc, the positive electrode is an air electrode formed by a carbon-based layer containing a catalyst, and the electrolyte is a nonaqueous electrolyte; the negative electrode and the positive electrode are separated by a diaphragm; the electrolyte is solid polymer electrolyte or room temperature ionic liquid electrolyte, and the non-aqueous electrolyte is adopted to prepare the zinc-air battery, so that the problems of electrode corrosion, dendrite formation, electrolyte drying, leaching and the like can be eliminated.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings that are needed in the embodiments will be briefly described below, and it will be obvious to those skilled in the art that other drawings can be obtained from these drawings without inventive effort.

Fig. 1 is a schematic view of a zinc-air cell of the present invention.

An illustration; 1-a negative electrode; 2-positive electrode; 3-electrolyte; 4-a membrane; 5-catalyst.

Detailed Description

In order to further explain the technical means adopted by the present invention and the effects thereof, the following detailed description is given with reference to the preferred embodiments of the present invention and the accompanying drawings.

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.

In the description of the present application, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate an orientation or positional relationship based on that shown in the drawings, merely for convenience of description and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be configured and operated in a particular orientation, and thus should not be construed as limiting the present application. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more features. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In this application, the term "exemplary" is used to mean "serving as an example, instance, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. The following description is presented to enable any person skilled in the art to make and use the application. In the following description, details are set forth for purposes of explanation. It will be apparent to one of ordinary skill in the art that the present application may be practiced without these specific details. In other instances, well-known structures and processes have not been shown in detail to avoid obscuring the description of the present application with unnecessary detail. Thus, the present application is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

Referring to fig. 1, an embodiment of the present invention provides a zinc-air battery, including: a negative electrode 1, a positive electrode 2, and an electrolyte 3. The negative electrode 1 is zinc metal, and zinc metal reserves are rich, the density is high, and the reducibility is strong. The zinc-air battery has the characteristics of high safety and low cost, and can maintain higher open-circuit voltage. The positive electrode 2 is an air electrode formed by a carbon base layer containing a catalyst 5, and the air electrode participates in the reaction substance which is oxygen in the air, so that the source is rich. When discharging, oxygen Reduction Reaction (ORR) occurs at the air electrode to release electric energy; upon charging, oxygen Evolution Reactions (OER) occur to store electrical energy.

Specifically, the electrolyte 3 is a nonaqueous electrolyte; the electrolyte 3 is a solid polymer electrolyte or a room temperature ionic liquid electrolyte.

The solid polymer electrolyte is an ion-conductive solid formed by dissolving a conductive salt into a polymer. The solid polymer electrolyte is applied to the zinc-air battery, and can eliminate the leaching phenomenon of electrolyte in a fluid water system, thereby prolonging the service life of the battery. In addition, the problem of electrode corrosion in solid polymer electrolytes is also alleviated by the near absence of convection. While room temperature ionic liquid electrolytes are ionic liquids that melt at or below room temperature, the different choices and combinations of cations and anions lead to a variety of room temperature ionic liquid electrolytes. Thus, the unique advantage of room temperature ionic liquid electrolytes is their tunability, the inherent volumetric disadvantages of aqueous electrolyte are not a problem for room temperature ionic liquid electrolytes, which makes them a safer alternative in batteries, and the complete ion is another feature of room temperature ionic liquid electrolytes from aqueous electrolytes. The aqueous electrolyte originates from the dissolution of salt in an aqueous solvent and consists of dissolved ions, charged or neutral combinations and solvent molecules, whereas the room temperature ionic liquid electrolyte is a salt that melts (liquefies) by supplying heat to the system to overcome the salt lattice energy, consisting of ions and combinations thereof only, without any molecular solvent. The ionic property ensures that the room temperature ionic liquid electrolyte used in the battery has a wide electrochemical window and has high electrode efficiency.

The aprotic room temperature ionic liquid electrolyte is used in the zinc-air battery system, and zinc corrosion caused by hydrogen evolution can be avoided due to the lack of protons in the electrolyte. Thus, the current efficiency of electrodepositing zinc in room temperature ionic liquid electrolytes is improved, and aprotic room temperature ionic liquid electrolytes also have the additional benefits of improving zinc deposition shape, preventing dendrite formation of zinc, and the like. The room temperature ionic liquid electrolyte cations have an effect on the deposition size, while the morphology and growth direction of the deposition are closely related to the room temperature ionic liquid electrolyte anions. In zinc air battery systems, the development of room temperature ionic liquid electrolyte-based electrolytes is of considerable benefit in terms of reduced dendrite formation, avoidance of electrolyte drying.

The negative electrode 1 and the positive electrode 2 are separated by a separator 4. A proper diaphragm in the zinc-air battery can control the ion permeability through the pore size distribution or the chemical property of a diaphragm body, so that the problem that ZnO is separated out to cover active sites is solved to a certain extent. Meanwhile, the zinc dendrite can be inhibited under a specific battery structure. When the battery is in cyclic operation, a proper diaphragm can lead the exchange current density to be distributed more uniformly at the anode interface, thereby slowing down or inhibiting the generation of zinc dendrites. In addition to isolating the anode and cathode of the battery in the battery, the zinc-air battery separator prevents short circuits, and also needs to have good wettability to the electrolyte in order to ensure high ionic conductivity. The electrolyte of zinc air cells is a strong base, which places high demands on the alkali resistance of the separator.

The performance requirements of the zinc-air battery separator include the following: insulation property. In a compact battery structure, in order to ensure that the anode and the cathode do not directly contact to cause a short circuit, the separator must have electronic insulation, i.e., electrons are only transported through an external circuit during charge and discharge. Electrochemical stability. In the strongly alkaline electrolyte, the nucleophilic aggressiveness of OH-makes the membrane structure very vulnerable. SAPKOTA studied cotton film, MAlkali resistance of F-250 synthetic resin film, PP (polypropylene) microporous membrane and nylon film. Although cotton cloth films and MF-250 synthetic resin films have good alkali resistance in nature, both of the separators are easily broken during actual use. Whereas PP and nylon films show better stability. Therefore, structural stability of the separator in the electrolyte for a long period of time is extremely important. In addition, in the case of battery operation, the separator needs to remain stable under a complex redox environment. Strength. The zinc-air battery separator should have a certain strength both during battery assembly and during actual battery use. More importantly, during cyclic charge and discharge, the separator is ensured not to be punctured by zinc dendrites to cause short circuit of the battery. Ion permeability. The ion permeability of the separator directly affects the rapid charge and discharge capability of the battery and the battery impedance. For zinc air cells, the carrier in the electrolyte is OH-, and the separator is required to increase the OH "passage rate as much as possible. Ion permeability of the separator without specific functional groups depends on the absorptivity of the electrolyte, which is related to the material, porosity, pore structure and distribution of the separator. Selectively permeable. One of the most important features of secondary zinc-air batteries is ion permselectivity. Excess of OH-sum

Will form->

It is easily decomposed into ZnO at the air anode covering the active sites, ultimately affecting cycle life. Therefore, the permeability of OH-is ensured, and +.>

Is the key point for realizing the cycle life increase of the secondary zinc-air battery.

In the embodiment, the diaphragm can adopt an anion exchange coating with a microphase separation structure obtained by copolymerizing an ionic monomer containing OH-and butyl methacrylate in a solvent, so that the problems of zincate stacking and zinc dendrite existing in a zinc-air battery can be overcome.

Alternatively, the separator may be prepared by dry process, where the polymer matrix is melted at high temperature, extruded under pressure to form a sheet structure, thermally annealed to convert from a viscous state to a highly elastic state, and stretched to form a regularly arranged sheet structure, and finally stretched to form pores.

The embodiment of the invention also provides a preparation method of the zinc-air battery, and the zinc-air battery adopts the zinc-air battery.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

It should be noted that the terms "first," "second," and the like in the description and claims of the present application and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that embodiments of the present application described herein may be capable of being practiced otherwise than as specifically illustrated and described herein.

The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A zinc-air battery, comprising: a negative electrode (1), a positive electrode (2) and an electrolyte (3), wherein the negative electrode (1) is metallic zinc, the positive electrode (2) is an air electrode formed by a carbon-based layer containing a catalyst (5), and the electrolyte (3) is a nonaqueous electrolyte; the negative electrode (1) and the positive electrode (2) are separated by a diaphragm (4); the electrolyte (3) is a solid polymer electrolyte or a room temperature ionic liquid electrolyte.

2. A zinc-air cell according to claim 1, characterized in that the separator (4) employs an anion exchange coating having a microphase separation structure obtained by copolymerizing an OH-containing ionic monomer with butyl methacrylate in a solvent.

3. A zinc-air cell according to claim 1, characterized in that the separator (4) is prepared by dry method, the polymer matrix is melted at high temperature, the sheet structure is extruded under pressure, the sheet structure is transformed from a viscous state to a high-elastic state by thermal annealing, the sheet structure is stretched to form a regular arrangement of sheet structures, and finally the stretching pore-forming is performed.

4. A zinc-air cell according to claim 1, characterized in that the separator (4) is prepared by wet process, the polyolefin resin, the plasticizer and the high-boiling point low-molecular porogen are mixed into a homogeneous system, extruded under high temperature and pressure and cooled rapidly, at which time the separator has already undergone phase separation, but the porogen remains on the separator; and (3) performing biaxial stretching to continuously expand the existing pores, and extracting the micromolecular pore-forming agent by using an organic volatile solvent to generate micropores.

5. A zinc-air cell according to claim 1, characterized in that the separator (4) is made by non-woven technology, by first arranging the various fibres in a random manner into a web, and then reinforcing them by physical and chemical means, or by using special binder fibres to improve the mechanical properties.

6. A zinc-air cell according to claim 1, characterized in that the separator (4) is prepared by solution casting, in which the polymer solute is dissolved in a volatile solvent, after the solution has been mixed uniformly, the film is coated on a smooth glass plate or other flat surface, and then the film is placed in a solvent which is miscible with the solvent but not in the body of the film or is directly dried, and a film of a certain porosity is obtained by evaporation or dissolution of the solvent.

7. A method for preparing a zinc-air cell, characterized in that the zinc-air cell is the zinc-air cell according to any one of claims 1 to 6.