CN103606686A - Air electrode for lithium air cells and preparation method of air electrode - Google Patents

Abstract

The invention discloses an air electrode for a lithium-air battery and a preparation method thereof. The air electrode has an ion-conductive three-dimensional network and an electronically conductive three-dimensional network at the same time. The ion-conductive three-dimensional network is composed of room temperature ion The liquid is formed, and the electronically conductive three-dimensional network is formed by the conductive agent. The air electrode is prepared by uniformly mixing 10-40 parts by weight of room-temperature ionic liquid and 60-90 parts by weight of conductive agent, and then immobilizing them on the surface of a porous current collector. Because the air electrode provided by the present invention has a double conductive network, the three-phase reaction interface formed by the electron conduction, ion conduction and oxygen required for the electrode reaction is greatly increased, and the transmission speed of the electrons and ions required for the reaction is accelerated, thereby The voltage polarization is reduced, and the application to lithium-air batteries shows excellent battery comprehensive performance, and has a good application prospect.

Description

A kind of air electrode for lithium-air battery and preparation method thereof

technical field

The invention relates to a liquid catalyst-based air electrode with a double three-dimensional conductive network that can be used for a lithium-air battery, and belongs to the technical field of chemical power sources.

Background technique

Although commercialized lithium-ion batteries have been widely used in various fields such as portable tools, digital products, aerospace, etc., because their energy density is limited by the intercalation reaction mechanism, it is difficult to meet the needs of electronic products for miniaturization and miniaturization. The use of electric vehicles for long-distance driving is required. Therefore, the development of secondary batteries with higher energy density has become a global research hotspot, and the research on lithium-air batteries has emerged as the times require.

The basic working principle of lithium-air batteries is that metal lithium is oxidized at the negative electrode during the discharge process, and then migrates to the surface of the air electrode through the electrolyte, and combines with oxygen from the air that is reduced on the surface of the porous air electrode, thereby providing the load with electrical energy. The biggest advantage of lithium-air batteries is that the positive active material is inexhaustible from the oxygen in the air, and it does not need to be stored inside the battery, so lithium-air batteries have an ultra-high theoretical energy density of 13200Wh/Kg , almost comparable to gasoline, becoming the Mount Everest of secondary batteries. Although the actual energy density of lithium-air batteries that have been reported so far has made great progress, unfortunately, lithium-air batteries have poor reversibility and severe polarization due to the slow electrochemical redox kinetics of the positive active material oxygen. The practical application of lithium-air batteries still faces great challenges.

In order to solve these problems, researchers have made a lot of efforts, including the development and preparation of high-performance catalysts (such as various metal oxides, various carbon-based materials, noble metal catalysts, and transition metal macrocyclic compounds, etc.) and the structural design of air electrodes. And so on, and achieved certain results. However, the catalysts currently studied are all in a solid state, and the traditional method of preparing electrodes makes the solid particles intermingled with non-conductive binders, which makes it difficult to form a three-dimensional conductive network inside the air electrode. According to the reaction principle of the air electrode, the electrode reaction occurs at the three-phase interface of the electronic conductive agent, ion conductive agent and oxygen, so the establishment of a three-dimensional conductive network inside the air electrode will greatly improve the performance of the electrode.

So far, poor electronic or ionic conductivity in existing designs leads to high voltage polarization and poor reversibility of air electrodes, so there is an urgent need in the field to develop a device that can simultaneously ensure good electronic conductivity and ionic conductivity. A conductive air electrode structure to reduce the voltage polarization of the lithium-air battery, improve its reversibility, and promote the realization of the practical application of the lithium-air battery.

Contents of the invention

In view of the above-mentioned problems in the prior art, the present invention aims to provide an air electrode for lithium-air batteries and a preparation method thereof, so as to promote the practical application of lithium-air batteries.

For realizing above-mentioned purpose of the invention, the technical scheme that the present invention adopts is as follows:

An air electrode for a lithium-air battery, having both an ion-conducting three-dimensional network and an electronically-conducting three-dimensional network, the ion-conducting three-dimensional network is formed by a room temperature ionic liquid with catalytic properties, and the electronically conducting three-dimensional network is formed by The conductive agent is formed.

The air electrode of the present invention is prepared by uniformly mixing 10-40 parts by weight of room temperature ionic liquid and 60-90 parts by weight of conductive agent, and then immobilizing them on the surface of the porous current collector.

As a preferred solution, the preparation method of the air electrode comprises the following steps:

a) uniformly mixing 10-40 parts by weight of room temperature ionic liquid and 60-90 parts by weight of conductive agent;

b) immobilizing the mixed slurry obtained in step a) on the porous current collector, then drying at 50-100° C., and then compressing the conductive active material and the porous current collector with a pressure of 6-10 MPa;

c) drying the electrode obtained in step b) to remove water at 50-100° C. to obtain the air electrode.

As a preferred solution, the porous current collector includes a metal porous current collector and an inorganic non-metallic porous current collector.

As a further preferred solution, the metal porous current collector includes foamed nickel, porous aluminum and porous stainless steel; the inorganic non-metallic porous current collector includes porous carbon material.

The room temperature ionic liquid contains nitrogen, fluorine, boron and other elements and has a catalytic function of reducing properties. It is recommended to be selected from 1-ethyl-3-methylimidazole bis(pentafluoro-ethylsulfonyl)amide, 1-ethyl Base-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, 1-methyl-3-octylimidazolium bis(trifluoromethylsulfonyl)amide, 1-butyl-3-methylimidazolium At least one of nonafluorobutylsulfonate and 1-ethyl-3-methylimidazolium hexafluorophosphate.

As a preferred solution, the conductive agent is selected from at least one of carbon-based conductive agents, polymer conductive agents and inorganic conductive agents.

As a further preferred solution, the carbon-based conductive agent is selected from at least one of acetylene black, conductive carbon black, activated carbon, mesoporous carbon materials, hollow carbon spheres, carbon fibers, and carbon nanotubes; the polymer conductive The agent is selected from polypyrrole or polyaniline; the inorganic conductive agent is a conductive oxide, such as SnO ₂ , a perovskite compound such as BaPbO ₃ , a non-stoichiometric metal oxide such as Ti ₄ O ₇ and the like.

As a preferred solution, the immobilization method includes impregnation method, in-situ deposition method and ultrasonic dispersion method; in the impregnation method, after the conductive agent is coated on the current collector by coating, the electrode is dried Finally, vacuum impregnation in the required ionic liquid, so that the ionic liquid enters the pores of the electronic conductive agent to form a three-dimensional ion conductive network; the in-situ deposition method is also to firstly apply the conductive agent on the current collector by coating. , drop the required ionic liquid on the electrode surface and wait for a period of time until the ionic liquid diffuses into the pores of the electronic conductive agent to form a three-dimensional ion conductive network; the ultrasonic dispersion method is to firstly disperse the conductive agent in the required ionic liquid , sonicate for a period of time, so that the ionic liquid is uniformly coated on the surface of the conductive agent, and then the air electrode with a double three-dimensional conductive network is prepared by a traditional ball mill coating method.

The principle of the present invention is: using a room-temperature ionic liquid with reducing properties as a catalyst, on the one hand, a three-dimensional ion-conducting network is formed inside the air electrode, and on the other hand, the same ionic liquid is used as an electrolyte, so that a ionic liquid is formed between the air electrode and the electrolyte. The relationship between the total flow and the branch flow, the electrolyte can enter various parts of the electrode along with the ionic liquid, and the ions generated by the reaction in the electrode can directly enter the electrolyte, thereby reducing the internal resistance of the battery, which is beneficial to the improvement of battery performance. In addition, the ionic liquid in the electrode also acts as a binder to a certain extent, and it is not even necessary to add a binder to the electrode, which can effectively reduce the weight of the electrode and help increase the capacity density of the electrode. It can also avoid the problem of battery performance degradation caused by the unstable performance of the traditional binder during the discharge process, which is conducive to improving the overall performance of the battery.

Compared with the prior art, the air electrode provided by the present invention has the following remarkable features:

1) Using the reducing ionic liquid as the catalyst saves the complex steps of preparing the solid catalyst and avoids the unstable chemical properties of the solid catalyst itself;

2) Combining the liquid ionic liquid with the solid conductive agent, so that the liquid can be in contact with the solid conductive agent in multiple directions. Compared with the combination of the solid catalyst and the solid conductive agent with a large interface energy, the interface between the two substances is greatly reduced. It is beneficial to the progress of the electrode reaction;

3) Using the same ionic liquid as the electrolyte and as the catalyst at the same time ensures a smooth channel for ion migration, reduces the internal resistance of ion migration, and is conducive to the improvement of battery performance;

4) The three-dimensional conductive network formed by room temperature ionic liquid is easier to prepare than the three-dimensional ion conductive network formed by in-situ generation, and has more continuity of ion conductivity;

5) Due to the liquid state of the ionic liquid, while the three-dimensional conductive network of the ionic liquid is formed, the mutual contact of the solid conductive agents is not hindered, and a three-dimensional electronically conductive network can be formed;

6) The formation of a double conductive network in the electrode greatly increases the electron conduction required for the electrode reaction, the three-phase reaction interface formed by ion conduction and oxygen, and at the same time accelerates the transmission speed of electrons and ions required for the reaction, so that it can be greatly improved Promote the electrode reaction and reduce the voltage polarization;

7) No binder can be used in the electrode material, which can effectively reduce the weight of the electrode material, help to increase the capacity density of the battery, and avoid the decline in battery performance due to unstable binder, which is beneficial to the overall performance of the battery improvement.

Compared with the preparation methods of various existing air electrodes, the preparation method of the present invention has the following advantages:

1. The preparation method is simple and easy;

2. It is not necessary to use a special binder, which avoids the degradation of battery performance due to the instability of the binder, and at the same time reduces the weight of the electrode, which is conducive to improving the performance of the electrode;

3. Pollution-free, green and environmentally friendly, the combination of ionic liquid and conductive agent can be realized by using a simple ball milling method, forming a three-dimensional ion conductive network and a three-dimensional electronic conductive network at the same time;

4. There are many types of room temperature ionic liquids and conductive agents, and air electrodes with different characteristics can be obtained through different combinations, so that the characteristics of the air electrodes can be adjusted;

5. The source of raw materials is abundant, and the preparation cost is low.

Description of drawings

Fig. 1 is the structural representation of the lithium-air battery provided by the present invention;

Fig. 2 is the timing charge and discharge curve of the lithium-air battery using the air electrode described in Example 3.

Detailed ways

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

Fig. 1 is a schematic structural view of a lithium-air battery prepared using an air electrode provided by the present invention, wherein: 1 is a metal lithium anode, 2 is an organic electrolyte, 3 is a solid electrolyte, and 4 is an air electrode provided by the present invention (including room temperature ions liquid 41 and solid conductive agent 42).

Comparative example 1

Acetylene black is used as the conductive agent, PVDF is used as the binder, and the two are added to NMP mixed ball mill at a weight ratio of 8:2, and then the ball milled slurry is dried to a certain extent and coated on the foamed nickel collector, and then the pressure Press on the machine with a pressure of 8MPa, and place the pressed electrode in a vacuum drying oven at 80°C for 12 hours to remove moisture from the electrode. The electrodes were then assembled in a lithium-air battery using metal Li//1M LiPF ₆ dissolved in EC/DMC (1:1)//LATP//dissolved 0.5M bis(trifluoromethylsulfonyl) Structure of 1-butyl-3-methylimidazolium tetrafluoroborate of lithium imide // air electrode. Then the assembled battery is subjected to electrochemical performance tests including regular charge and discharge tests and capacity tests. It can be seen from Table 1 that the discharge voltage of the battery is as low as 2.73V, the charging voltage is 4.2V, the Coulombic efficiency is only 65%, and the specific capacity of the first discharge is only 171.5mAh/g.

Comparative example 2

Adopting acetylene black as the conductive agent, manganese dioxide as the catalyst, and PVDF as the binder, the three are added into NMP in a weight ratio of 6:2:2 and then ball milled. The method of preparing the electrode and the battery assembly are the same as in Comparative Example 1, and then The electrochemical performance test of the assembled battery includes timing charge and discharge test and capacity test. It can be seen from the data in Table 1 that the first discharge voltage of the battery is lower, the Coulombic efficiency is only 66%, and the capacity is 1193mAh/g.

Comparative example 3

Acetylene black is used as a conductive agent, and 0.5 mol/L of bis(trifluoromethylsulfonyl)imide lithium dissolved in 0.5 mol/L of ionic liquid 1-carboxymethyl-3-methylimidazolium chloride, which does not have reducing properties, is used as an additive. The two were mixed and ball-milled at a weight ratio of 8:2, and the electrode preparation method and battery assembly method were the same as in Comparative Example 1. The assembled battery is then subjected to electrochemical performance tests including charge and discharge tests and capacity tests. It can be seen from the data in Table 1 that the first discharge voltage of the battery is very low, indicating that the reducing effect of the ionic liquid is relatively weak, the charging voltage is high, the Coulombic efficiency is only 67%, and the capacity is 1265mAh/g.

Example 1

Using acetylene black as the conductive agent, dissolving 1-ethyl-3-methylimidazolium tetrafluoroborate with 0.5mol/L of bis(trifluoromethylsulfonyl)imide lithium as the catalyst, the conductive agent and the catalyst with The weight ratio of 8:2 is mixed with ball milling, and then the slurry after ball milling is dried to a certain extent and then coated on the nickel foam current collector, and then pressed on the press at a pressure of 8MPa, and the pressed electrode is placed in a vacuum drying box Dry at 80°C for 12 hours to remove moisture from the electrode. The electrodes were assembled in a lithium-air battery using metal Li//1M LiPF ₆ dissolved in EC/DMC (1:1)//LATP//0.5mol/L bis(trifluoromethylsulfonyl) Lithium amide (LiTFSI) is dissolved in the structure of 1-butyl-3-methylimidazolium tetrafluoroborate//air electrode, and then the assembled battery is tested for electrochemical performance, including timing charge and discharge tests, and capacity tests. The results obtained are shown in Table 1. Compared with the comparative example, it can be seen that the first discharge voltage has been greatly increased to 2.82V, the charging voltage has been significantly reduced to 3.95V, the Coulombic efficiency has reached 71.4%, and the capacity has also increased to 1500mAh. /g, indicating that the air electrode with double conductive network structure can effectively improve the battery polarization and increase the specific capacity of the battery.

Example 2

Using acetylene black as the conductive agent, 1-ethyl-3-methylimidazolium tetrafluoroborate dissolved in 0.5mol/L of bis(trifluoromethylsulfonyl)imide lithium as the catalyst, the conductive agent and the catalyst The weight ratio of 9:1 is mixed and ball milled, and the preparation process and conditions are the same as those in Example 1. The electrodes were then assembled in a lithium-air battery using metal Li//1M LiPF ₆ dissolved in EC/DMC (1:1)//LATP//dissolving 0.5mol/L of bis(trifluoromethylsulfonate The structure of 1-ethyl-3-methylimidazolium tetrafluoroborate//air electrode of lithium imide, and then the assembled battery is tested for electrochemical performance, including regular charge and discharge test and capacity test, test The results are shown in Table 1. Compared with the comparative example, the voltage polarization and capacity have been improved, but compared with Example 1, the polarization performance and capacity of the battery are not good. The reduction of ionic liquids further shows that the room temperature ionic liquids in the electrodes play a key role in improving the performance of the battery.

Example 3

Using acetylene black as the conductive agent, 1-ethyl-3-methylimidazolium tetrafluoroborate dissolved in 0.5mol/L of bis(trifluoromethylsulfonyl)imide lithium as the catalyst, the conductive agent and the catalyst The weight ratio of 6:4 is mixed and ball milled, and the preparation process and conditions are the same as those in Example 1. The electrodes were then assembled in a lithium-air battery using metal Li//1M LiPF ₆ dissolved in EC/DMC (1:1)//LATP//dissolving 0.5mol/L of bis(trifluoromethylsulfonate The structure of 1-ethyl-3-methylimidazolium tetrafluoroborate//air electrode of lithium imide, and then the assembled battery is subjected to electrochemical performance tests including regular charge and discharge tests and capacity tests. The timing charge and discharge curves of the first five weeks are shown in Figure 2. The first discharge voltage is 2.89V, the first charge voltage is 3.57V, and the corresponding Coulomb cycle efficiency is 81%, showing good polarization performance. At the same time, the charge and discharge voltage of the battery does not change much after five weeks of regular cycle, which shows that it has good cycle stability. At the same time, the capacity performance test was carried out on the battery, and the first discharge capacity of 2396mAh/g can be obtained. Compared with the data of each comparative example described in Table 1, the lithium-air battery composed of the air electrode of this composition shows good battery polarization performance and capacity performance, thereby further proving the effectiveness of this kind of dual conductive network structure. The advantages of air electrodes in improving the overall performance of batteries.

Example 4

Activated carbon is used as a conductive agent, 1-ethyl-3-methylimidazolium tetrafluoroborate dissolved in 0.5mol/L of bis(trifluoromethylsulfonyl)imide lithium is used as a catalyst, and the conductive agent and catalyst are The weight ratio of 8:2 is mixed and ball milled, and the preparation process and conditions are the same as those in Example 1. The electrodes were then assembled in a lithium-air battery using metal Li//1M LiPF ₆ dissolved in EC/DMC (1:1)//LATP//dissolving 0.5mol/L of bis(trifluoromethylsulfonate The structure of the 1-ethyl-3-methylimidazolium tetrafluoroborate//air electrode of lithium imide, and then the assembled battery is subjected to electrochemical performance tests including regular charge and discharge tests and capacity tests, and obtained better results.

Example 5

Using mesoporous carbon CMK-3 as the conductive agent, 1-ethyl-3-methylimidazolium tetrafluoroborate dissolved in 0.5mol/L lithium bis(trifluoromethylsulfonyl)imide as the catalyst, conducts electricity Agent and catalyst are mixed and ball-milled at a weight ratio of 8:2, and the preparation process and conditions are the same as those in Example 1. The electrodes were then assembled in a lithium-air battery using metal Li//1MLiPF ₆ dissolved in EC/DMC (1:1)//LATP//dissolving 0.5mol/L of bis(trifluoromethylsulfonyl ) the structure of 1-ethyl-3-methylimidazolium tetrafluoroborate//air electrode of lithium imide, and then the assembled battery was tested for electrochemical performance. The results show that the prepared electrode has a higher first discharge voltage and a lower charge voltage, corresponding to a higher first Coulombic efficiency. The specific capacity of the first discharge is also much higher than that of the traditional comparative example.

Example 6

Acetylene black conductive agent is used, 1-ethyl-3-methylimidazolium tetrafluoroborate dissolved in 0.5mol/L of bis(trifluoromethylsulfonyl)imide lithium is used as a catalyst, and the conductive agent and catalyst are mixed with 8 : 2 weight ratio mixing ball milling, preparation process and condition are identical with embodiment 1. The electrodes were then assembled in a lithium-air battery using metal Li//1M LiPF ₆ dissolved in EC/DMC (1:1)//LATP//dissolved with 0.5mol/L of bis(trifluoromethyl 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide of lithium sulfonyl)imide//The structure of the air electrode, and then the assembled battery is tested for electrochemical performance including timing charge and discharge tests , capacity test. Compared with the electrode prepared by the traditional method, such as in Comparative Example 1, the battery has a higher discharge voltage and a lower charge voltage, corresponding to a higher first-time Coulombic efficiency, but it is different from the electrolysis of the catalyst and the air electrode side in Example 5. Compared with the battery using the same ionic liquid as the liquid, the polarization performance of the battery is not as good as that of Example 5. It is speculated that the reason is that batteries using the same ionic liquid have good electrode wettability, and the pore structure of CMK-3 also increases the channels for electrolyte wetting, which is beneficial to the improvement of battery performance.

Example 7

Using acetylene black as the conductive agent, 1-ethyl-3-methylimidazolium tetrafluoroborate dissolved in 0.5mol/L of bis(trifluoromethylsulfonyl)imide lithium as the catalyst, the conductive agent and the catalyst The weight ratio of 8:2 is mixed and ball milled, and the preparation process and conditions are the same as those in Example 1. The electrodes were then assembled in a lithium-air battery using metal Li//1M LiPF ₆ dissolved in EC/DMC (1:1)//LATP//dissolving 0.5mol/L of bis(trifluoromethylsulfonate The structure of 1-ethyl-3-methylimidazolium hexafluorophosphate of lithium imide//air electrode, and then the assembled battery is subjected to electrochemical performance tests including regular charge and discharge tests and capacity tests. The results show that the battery exhibits good capacity performance and polarization performance.

Example 8

Acetylene black is used as a conductive agent, and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide dissolved in 0.5mol/L lithium bis(trifluoromethylsulfonyl)imide is used as a catalyst. The conductive agent and the catalyst were mixed and ball-milled at a weight ratio of 8:2, and the preparation process and conditions were the same as those in Example 1. The electrodes were then assembled in a lithium-air battery using metal Li//1M LiPF ₆ dissolved in EC/DMC (1:1)//LATP//dissolving 0.5mol/L of bis(trifluoromethylsulfonate 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide//air electrode structure of lithium imide, and then the assembled battery was tested for electrochemical performance. The result shows that the battery has good polarization performance, which is better than that of the battery in Example 5. It is speculated that the reason is that not only fluorine atoms, but also sulfur atoms, nitrogen atoms, etc. are present in the ionic liquid used, which is conducive to the improvement of its catalytic performance, so the battery has good polarization performance.

Example 9

Acetylene black is used as the conductive agent, and 1-ethyl-3-methylimidazolium bis(pentafluoro-ethylsulfonyl)amide dissolved with 0.5mol/L lithium bis(trifluoromethylsulfonyl)imide is used as the catalyst , the conductive agent and the catalyst were mixed and ball-milled at a weight ratio of 8:2, and the preparation process and conditions were the same as those in Example 1. The electrodes were then assembled in a lithium-air battery using metal Li//1M LiPF ₆ dissolved in EC/DMC (1:1)//LATP//dissolving 0.5mol/L of bis(trifluoromethylsulfonate 1-ethyl-3-methylimidazolium bis(pentafluoro-ethylsulfonyl)amide//air electrode structure of lithium imide, and then the assembled battery is tested for electrochemical performance including timing charge and discharge test , capacity test. The results show that the battery exhibits good capacity performance and polarization performance.

Example 10

Using mesoporous carbon CMK-3 as the conductive agent, 1-methyl-3-octylimidazole bis(trifluoromethylsulfonyl) dissolved in 0.5mol/L lithium bis(trifluoromethylsulfonyl)imide The amide was used as the catalyst, and the conductive agent and the catalyst were mixed and ball-milled at a weight ratio of 8:2. The preparation process and conditions were the same as those in Example 1. The electrodes were then assembled in a lithium-air battery using metal Li//1M LiPF ₆ dissolved in EC/DMC (1:1)//LATP//dissolving 0.5mol/L of bis(trifluoromethylsulfonate 1-methyl-3-octylimidazole bis(trifluoromethylsulfonyl)amide//air electrode structure of lithium imide, and then the assembled battery was tested for electrochemical performance. The results show that the prepared electrode has a higher first discharge voltage and a lower charge voltage, corresponding to a higher first Coulombic efficiency. The specific capacity of the first discharge is also much higher than that of the traditional comparative example.

Example 11

Activated carbon is used as the conductive agent, 1-butyl-3-methylimidazolium nonafluorobutyl sulfonate dissolved in 0.5mol/L lithium bis(trifluoromethylsulfonyl)imide is used as the catalyst, and the conductive agent Mix ball milling with the catalyst at a weight ratio of 8:2, the preparation process and conditions are the same as those in Example 1. The electrodes were then assembled in a lithium-air battery using metal Li//1MLiPF ₆ dissolved in EC/DMC (1:1)//LATP//dissolving 0.5mol/L of bis(trifluoromethylsulfonyl ) the structure of 1-butyl-3-methylimidazolium nonafluorobutylsulfonate//air electrode of lithium imide, and then perform electrochemical performance tests on the assembled battery, including regular charge and discharge tests and capacity tests, Better results were obtained.

Table 1

It can be seen from Table 1 that the air electrode provided by the present invention, with the increase of the room temperature ionic liquid in the air electrode, the polarization performance and capacity of the battery have been greatly improved, thus illustrating the dual conductive network structure. The room temperature ionic liquid in the air electrode does play the role of catalyst and ion conduction, and it does have the advantage of significantly improving the overall performance of the battery.

Finally, it is necessary to explain here that: the above examples are only used to further describe the technical solutions of the present invention in detail, and cannot be interpreted as limiting the protection scope of the present invention. Non-essential improvements and adjustments all belong to the protection scope of the present invention.

Claims (10)

1. An air electrode for a lithium-air battery, characterized in that: the air electrode has an ion-conducting three-dimensional network and an electronically conducting three-dimensional network, and the ion-conducting three-dimensional network is formed by a room temperature ionic liquid with catalytic properties , the electronically conductive three-dimensional network is formed by a conductive agent. 2. A method for preparing the air electrode according to claim 1, characterized in that: 10-40 parts by weight of the room temperature ionic liquid and 60-90 parts by weight of the conductive agent are uniformly mixed and then immobilized on the surface of the porous current collector. made. 3. The method of claim 2, comprising the steps of: a) uniformly mixing 10-40 parts by weight of room temperature ionic liquid and 60-90 parts by weight of conductive agent; b) immobilizing the mixed slurry obtained in step a) on the porous current collector, then drying at 50-100° C., and then compressing the conductive active material and the porous current collector with a pressure of 6-10 MPa; c) drying the electrode obtained in step b) to remove water at 50-100° C. to obtain the air electrode. 4. The method according to claim 2 or 3, characterized in that: the porous current collector comprises a metal porous current collector and an inorganic non-metallic porous current collector. 5. The method according to claim 4, characterized in that: said metal porous current collector comprises foamed nickel, porous aluminum and porous stainless steel. 6. The method of claim 4, wherein the inorganic non-metallic porous current collector comprises porous carbon material. 7. The method according to claim 2 or 3, characterized in that: the room temperature ionic liquid is selected from 1-ethyl-3-methylimidazole bis(pentafluoro-ethylsulfonyl)amide, 1-ethyl Base-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, 1-methyl-3-octylimidazolium bis(trifluoromethylsulfonyl)amide, 1-butyl-3-methylimidazolium At least one of nonafluorobutylsulfonate and 1-ethyl-3-methylimidazolium hexafluorophosphate. 8. The method according to claim 2 or 3, characterized in that the conductive agent is selected from at least one of carbon-based conductive agents, polymer conductive agents and inorganic conductive agents. 9. The method according to claim 8, characterized in that: the carbon-based conductive agent is selected from acetylene black, conductive carbon black, activated carbon, mesoporous carbon material, hollow carbon spheres, carbon fibers, carbon nanotubes At least one; the polymer conductive agent is selected from polypyrrole or polyaniline; the inorganic conductive agent is a conductive oxide. 10. The method according to claim 2 or 3, characterized in that: the immobilization method includes impregnation method, in-situ deposition method and ultrasonic dispersion method.

Images