CN111446454A - Application of electronic compound as lithium-air battery anode catalyst material - Google Patents

Abstract

The invention relates to the application of an electronic compound as a positive electrode catalyst material for a lithium-air battery, and the molecular formula of the electronic compound is: A _x By O _z ^- _n : 2ne- or C ₂ N: e-; wherein A is a low ^- cost Large radius cation, B is high valence small radius cation, C is alkaline earth metal cation. The preparation method includes direct high temperature reduction method, metal vapor reduction method and hydrogen atmosphere reduction method. Compared with the prior art, the present invention uses the electronic compound as the positive electrode catalyst material of the lithium-air battery, which can provide electrons for the reaction, and has a good bifunctional catalytic effect on the oxygen electrode reaction, thereby improving the discharge specific capacity of the battery and reducing the energy consumption. Charge and discharge overpotential, improve rate performance and cycle performance.

Description

Application of an electronic compound as a cathode catalyst material for lithium-air batteries

technical field

The invention belongs to the field of lithium-air batteries, and in particular relates to an application method of an electronic compound as a cathode catalyst material of a lithium-air battery.

Background technique

In recent years, lithium-air batteries have received extensive attention due to their ultra-high theoretical energy density (11400 Wh·kg ^-1 ) and rechargeability, and are promising next-generation energy storage and conversion devices. The negative active material of the lithium-air battery is metallic lithium, and the positive active material is oxygen in the air. Its working principle is based on the oxidation/reduction reaction centered on metallic lithium on the negative electrode and the reduction/oxidation reaction of oxygen on the air electrode. During the discharge process, the oxygen on the air electrode undergoes a reduction reaction (ORR), with the electrons passed through the external circuit and the lithium ions passed through the electrolyte/diaphragm (electrons and lithium ions are generated by the oxidation reaction of the metal lithium of the negative electrode) A reaction occurs to form lithium peroxide. During the charging process, lithium peroxide decomposes on the air electrode to generate oxygen (OER), lithium ions and electrons. The lithium ions are transferred to the negative electrode through the electrolyte/separator, and combine with the electrons transferred through the external circuit to form metallic lithium.

Although the comprehensive performance of lithium-air batteries has been greatly improved in recent years, its current actual energy density is still far lower than the theoretical value. This is because there are still some problems to be solved in lithium-air batteries, mainly including negative electrode lithium dendrites. , electrolyte instability, production of by-products, etc. Among them, one of the key factors affecting the comprehensive performance of lithium-air batteries is that the kinetic rates of ORR and OER on the air cathode lag significantly behind the dissolution and deposition rates of lithium metal in the anode, which leads to the main source of polarization in lithium-air batteries. on the air cathode. In practical work, in order to accelerate the rate of ORR/OER to further improve the performance of lithium-air batteries, bifunctional catalysts that catalyze both ORR and OER are often used. The currently used catalysts mainly include carbon materials, noble metals and their alloys, transition Metal oxides and transition metal sulfides, etc. Carbon materials have low specific discharge capacity and poor stability when used as cathode catalysts for lithium-air batteries. Currently, they are mainly used as catalyst carriers to form composite catalysts together with other catalyst materials. Although noble metal and its alloy catalysts have high activity, they have high costs and limited resources. The catalytic properties of transition metal oxides and sulfides are difficult to meet practical needs. None of these catalyst materials can meet the requirements of activity, stability, price, etc. at the same time. Therefore, the search for new efficient catalyst materials is of great significance for the development and application of Li-air batteries.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide an application of an electronic compound as a cathode catalyst material for a lithium-air battery in order to overcome the above-mentioned defects in the prior art.

The object of the present invention can be achieved through the following technical solutions: the application of an electronic compound as a cathode catalyst material for a lithium-air battery.

Further, the molecular formula of the electronic compound is: A _x By O _zn : _2ne ^- or C ₂ N: e ^- ; wherein A is a low-valent large-radius cation, B is a high-valent small-radius cation, and C is an alkaline earth metal cation .

Further, the low-valent large-radius cations include Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , La ³⁺ , Eu ³⁺ , Y ³⁺ , Sn ²⁺ or Cd ²⁺ , and the high ^- valent small-radius cations The cations include Ti ⁴⁺ , Si ⁴⁺ or Al ³⁺ , and the alkaline earth metal cations include Ca ²⁺ , Sr ²⁺ or Ba ²⁺ .

Further, the described A is the same cation or the cation is partially substituted by other one or more cations, the described B is the same cation or the cation is partially substituted by other one or more cations, the described C is the same cation or the cation is partially substituted with one or more other cations.

Further, the electronic compound is prepared from a precursor by a direct high temperature reduction method, a metal vapor reduction method or a hydrogen atmosphere reduction method, wherein the precursor includes an oxide containing free oxygen (A _{x By O z )} or an alkaline earth metal low Nitride (C ₃ N ₂ ).

Further, the direct high-temperature reduction method includes the following steps: placing the precursor in a carbon crucible, and directly reducing the electronic compound at a high temperature in an inert gas atmosphere, the reduction temperature is 900-1500°C, and the reduction time is 8-24h , the inert gas is nitrogen or argon.

Further, the metal vapor reduction method includes the following steps: placing the precursor in a quartz crucible, placing a reducing agent metal at both ends of the tube furnace, reducing the electronic compound under the atmosphere of the metal vapor generated by heating, and reducing the temperature The temperature is 700～1100℃, the reduction time is 24～240h, and the reducing agent metal includes: Ca, Mg, Al or Ti.

Further, the hydrogen atmosphere reduction method includes the following steps: placing the precursor in a quartz crucible, reducing it in a 20% H ₂ /80% N ₂ atmosphere to obtain an electronic compound, the reduction temperature is 1000-1500 ° C, reducing The time is 2 to 10h.

Among them, the direct high-temperature reduction method is preferred, because the reduction of the precursor in a metal vapor atmosphere or a hydrogen atmosphere usually introduces impurities, poor product crystallinity, low electrical conductivity, and harsh reaction conditions. The electronic compound obtained by the direct high-temperature reduction method has high purity, good crystallinity and high conductivity, and the electron concentration is higher, which has a better catalytic effect on the electrochemical reaction of the oxygen electrode (positive electrode) of the lithium-air battery. The experimental conditions and cost are more advantageous, and it can better meet the actual production needs.

Further, the described application specific method is as follows:

(1) Take the electronic compound as the positive electrode material, disperse it in anhydrous ethanol together with the conductive agent and the binder, stir evenly to make a slurry, then spray the slurry on the substrate, and dry it to obtain a loading of 0.5～ 10mg·cm ^-2 positive electrode sheet.

(2) Using the positive electrode sheet as the positive electrode, the metal lithium sheet as the negative electrode, the polyolefin porous film and the glass fiber film as the separator, adding electrolyte, and assembling a lithium-air battery in an argon glove box.

Further, the mass ratio of the electronic compound, the conductive agent and the binder is 3:6:1, and the conductive agent includes Super P, Ketjen Balck (KB), Vulcan XC-72, Black Pearl (BP 2000) or CNT, and the binder includes PTFE, PVDF or PVA.

Further, the substrate includes nickel foam, carbon paper, carbon cloth, steel wire mesh or aluminum mesh.

Further, the electrolyte includes LiTFSI/TEGDME, LiCF ₃ SO ₃ /TEGDME, LiTFSI/DMSO, LiClO ₄ /DMSO or LiPF ₆ /EC:DMC [1:1 (v/v)], and the concentration of the electrolyte is 0.1～10M.

Compared with the prior art, the beneficial effects of the present invention are:

The present invention selects electronic compound as the positive electrode catalyst material of lithium-air battery. The electronic compound is an ionic compound rich in valence electrons, wherein the excess electrons do not occupy atomic orbitals, but act as anions, which are localized in lattice gaps. The general method for synthesizing electronic compounds is to further reduce on the basis of the precursor, so the composition of the precursor oxide A _{x By O z must} contain free oxygen ions (O ^2- ) that are easily reduced. The free oxygen ion is connected to the weakly ionic A-site ion but not to the covalently-strong B-site ion, so A is a low-valent large-radius cation, and B is a high-valent small-radius cation (the smaller the ionic radius, the more covalently Strong; the larger the ionic radius, the weaker the ionicity; the less the number of charges carried by the ion, the weaker the ionicity). The excess electrons in the electronic compound move freely in the voids of the framework structure formed by the cation, which can provide electrons for the reaction and thus have a good promotion effect on the electrode reaction.

The electronic compound material of the invention, as the positive electrode catalyst material of the lithium-air battery, can provide electrons for the electrode reaction and accelerate the kinetics of the oxygen electrode reaction, thereby increasing the discharge specific capacity of the battery, reducing the overvoltage of the battery, and improving the rate performance and cycle of the battery. stability.

Description of drawings

Figure 1: SEM image of the [Ca ₂₄ Al ₂₈ O ₆₄ ] ⁴⁺ :4e ^- electron compound prepared in Example 1;

Figure 2: XRD pattern of [Ca ₂₄ Al ₂₈ O ₆₄ ] ⁴⁺ :4e ^- electron compound prepared in Example 1;

Fig. 3 is a graph comparing the battery performance when the electronic compounds prepared in Examples 1-4 and Comparative Examples 1-2 are used as cathode catalyst materials for lithium-air batteries.

Detailed ways

The embodiments of the present invention are described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and provides a detailed implementation manner and a specific operation process, but the protection scope of the present invention is not limited to the following implementation. example.

Example 1: Application of [Ca ₂₄ Al ₂₈ O ₆₄ ] ⁴⁺ : 4e ^- electron compound in lithium-air battery

Weigh 200mg Ca ₂₄ Al ₂₈ O ₆₆ and place it in a carbon crucible, put the carbon crucible into a high-temperature tube furnace, evacuate to a negative pressure, continue to feed argon, and calcine under argon protection at a calcination temperature of 1350°C, The heating rate is 5°C/min, the calcination time is 24h, and the furnace is cooled after the calcination to obtain [Ca ₂₄ Al ₂₈ O ₆₄ ] ^{4+ :} 4e -electronic compound. Figure 1 and Figure 2 are the SEM photograph and the XRD spectrum of the electronic compound, respectively.

[Ca ₂₄ Al ₂₈ O ₆₄ ] ⁴⁺ : 4e ^- electronic compound powder is used as cathode catalyst material, Super P is used as conductive agent, PTFE is used as binder, and the mass ratio of catalyst, conductive agent and binder is 3:6 Disperse in absolute ethanol at a ratio of : 1, stir magnetically until the dispersion is uniform to obtain a catalyst slurry, spray the slurry evenly on the foamed nickel substrate with a spray gun, and vacuum dry it at 60 °C overnight to obtain a positive electrode with a loading of 0.5 mg·cm ^-2 piece.

Using an improved Swagelock mold, the positive electrode sheet is used as the positive electrode, the lithium metal sheet is used as the negative electrode, the polyolefin porous film and the glass fiber film are used as the double-layer separator, and 0.1M LiTFSI/TEGDME is used as the electrolyte to assemble the lithium-air battery in an argon glove box. .

The charge-discharge performance test of the lithium-air battery was carried out on the LAND battery test equipment (Wuhan Landian Electronics Co., Ltd.). The battery was placed in an oxygen glove box with a water content of less than 0.1 ppm. The discharge cut-off voltage was 2.0V, and the current density was 100mA·g ^-1 . After the discharge, the same capacity charge was performed at the same current density to obtain the battery charge-discharge curve. The limited discharge specific capacity is 500mAh·g ^-1 , the current density is 100mA·g ^-1 , the discharge cut-off voltage is 2.0V, and the cycle performance curve is obtained. The discharge specific capacity, overpotential and cycle number of the battery are shown in Figure 3. It can be seen from the figure that the lithium-air battery has a discharge specific capacity of 6064mAh·g ^-1 , an overpotential of 1.28V, and a cycle life of 205 cycles. Compared with Super P and Ca ₂₄ Al ₂₈ O ₆₆ used in Comparative Example 1 and Comparative Example 2, respectively, the lithium-air battery based on [Ca ₂₄ Al ₂₈ O ₆₄ ] ⁴⁺ :4e ^- material has a larger discharge specific capacity, The lower overpotential and more cycles indicate that the [Ca ₂₄ Al ₂₈ O ₆₄ ] ⁴⁺ : 4e ^- material prepared by the present invention has excellent catalytic performance, and has a bifunctional catalytic effect on ORR/OER. The specific capacity and cycle performance of the battery are improved.

Example 2: Application of [Ca ₂ N] ⁺ : e -electron compound in lithium ^- air battery

Weigh 150mg of Ca ₃ N ₂ and place it in a carbon crucible, put the carbon crucible into a high temperature tube furnace, evacuate to a negative pressure, continue to feed argon gas, and calcine under the protection of argon gas, the calcination temperature is 900 ° C, the heating rate The temperature is 5°C/min, and the calcination time is 12h. After the calcination is completed, it is cooled in the furnace to obtain [Ca ₂ N] ^{+ :} e -electronic compound. A positive electrode sheet was prepared by the same method as in Example 1, a lithium-air battery was assembled, and an electrochemical test was carried out. The discharge specific capacity, overpotential and cycle number of the battery are shown in Figure 3. It can be seen from the figure that the lithium-air battery has a discharge specific capacity of 5631mAh·g ^-1 , an overpotential of 1.32V, and a cycle life of 186 cycles. Compared with Super P and Ca ₂₄ Al ₂₈ O ₆₆ used in Comparative Example 1 and Comparative Example 2, respectively, the lithium-air battery based on [Ca ₂ N] ⁺ :e ^-material has a larger discharge specific capacity and a lower discharge capacity. The potential and more cycle times indicate that the [Ca ₂ N] ⁺ :e ^- material prepared by the present invention has excellent catalytic performance, has bifunctional catalytic effect on ORR/OER, and greatly improves the specific capacity and cycle of the battery. performance.

Example 3: Application of [Ca ₂₄ Al ₂₄ Sn ₄ O ₆₄ ] ⁴⁺ : 4e ^- electronic compound in lithium-air battery

Weigh 300mg of Ca ₂₄ Al ₂₄ Sn ₄ O ₆₆ precursor and place it in a carbon crucible, put the carbon crucible into a high temperature tube furnace, evacuate to negative pressure, continue to pass argon gas, calcine under the protection of argon gas, calcine The temperature is 1500°C, the heating rate is 5°C/min, and the calcination time is 8h. After the calcination is completed, the furnace is cooled to obtain [Ca ₂₄ Al ₂₄ Sn ₄ O ₆₄ ] ^{4+ :} 4e -electronic compound. A positive electrode sheet was prepared by the same method as in Example 1, a lithium-air battery was assembled, and an electrochemical test was carried out. The discharge specific capacity, overpotential and cycle number of the battery are shown in Figure 3. It can be seen from the figure that the lithium-air battery has a discharge specific capacity of 8258mAh·g ^-1 , an overpotential of 0.95V and a cycle life of 290 cycles. These properties are not only better than the data of Comparative Example 1 and Comparative Example 2, but also compared with [Ca ₂₄ Al ₂₈ O ₆₄ ] ⁴⁺ : 4e ⁻ prepared in Example 1, based on [Ca ₂₄ Al ₂₄ Sn ₄ O ₆₄ ] ⁴⁺ : 4e ^- Li-air battery has a larger discharge specific capacity, lower overpotential and more cycles, indicating that doping the A or B site of the electronic compound can improve the catalytic performance of the material.

Example 4: Application of [Ba ₂ N] ⁺ : e -electronic compound in lithium ^- air battery

Weigh 200mg Ba ₃ N ₂ and place it in a carbon crucible, put the carbon crucible into a high temperature tube furnace, evacuate to a negative pressure, continuously pass argon gas, and calcine under the protection of argon gas, the calcination temperature is 1300 ° C, the heating rate The temperature is 5°C/min, and the calcination time is 15h. After the calcination is completed, it is cooled in the furnace to obtain [Ba ₂ N] ^{+ :} e -electronic compound. A positive electrode sheet was prepared by the same method as in Example 1, a lithium-air battery was assembled, and an electrochemical test was carried out. The discharge specific capacity, overpotential and cycle number of the battery are shown in Figure 3. It can be seen from the figure that the lithium-air battery has a discharge specific capacity of 4870mAh·g ^-1 , an overpotential of 1.5V, and a cycle life of 147 cycles. Compared with Super P and Ca ₂₄ Al ₂₈ O ₆₆ used in Comparative Example 1 and Comparative Example 2, respectively, the lithium-air battery based on [Ba ₂ N] ⁺ :e ^-material has a larger discharge specific capacity and a lower discharge capacity. The potential and more cycles show that the [Ba ₂ N] ⁺ :e ^- material prepared by the present invention has excellent catalytic performance, has bifunctional catalytic effect on ORR/OER, and greatly improves the specific capacity and cycle of the battery. performance.

Example 5: Application of [Ca ₂₀ Cd ₄ Al ₂₈ O ₆₄ ] ⁴⁺ : 4e ^- electron compound in lithium-air battery

Weigh 200mg of Ca ₂₀ Cd ₄ Al ₂₈ O ₆₆ and place it in a quartz crucible. At the same time, weigh 200mg of metallic Ca particles and place them on both ends of a high temperature tube furnace, evacuate to negative pressure, heat up to 700°C, hold for 240h, and heat up at a rate of The temperature is 5°C/min. After calcination is completed, it is cooled in the furnace to obtain [Ca ₂₀ Cd ₄ Al ₂₈ O ₆₄ ] ^{4+ :} 4e -electron compound.

[Ca ₂₀ Cd ₄ Al ₂₈ O ₆₄ ] ⁴⁺ : 4e ^- electronic compound powder is used as cathode catalyst material, KB is used as conductive agent, PVDF is used as binder, and the mass ratio of catalyst, conductive agent and binder is 3: Disperse in absolute ethanol at a ratio of 6:1, magnetically stir until the dispersion is uniform to obtain catalyst slurry, spray the slurry on the carbon paper substrate with a spray gun, and vacuum dry at 60 °C overnight to obtain a positive electrode with a loading of 10 mg·cm ^-2 piece.

Using an improved Swagelock mold, with the positive electrode sheet as the positive electrode, the metal lithium sheet as the negative electrode, the polyolefin porous membrane and the glass fiber membrane as the double-layer separator, and 2M LiCF ₃ SO ₃ /TEGDME as the electrolyte, the lithium ion was assembled in an argon glove box. Air battery.

The charge-discharge performance test of the lithium-air battery was carried out on the LAND battery test equipment. The battery was placed in an oxygen glove box with a water content of less than 0.1 ppm. Before the test, it was left standing in an oxygen atmosphere for 2 hours. The density was 200 mA·g ^-1 , and after the discharge was completed, the battery was charged with equal capacity at the same current density to obtain the battery charge-discharge curve. The limited discharge specific capacity is 1000mAh·g ^-1 , the current density is 200mA·g ^-1 , the discharge cut-off voltage is 2.0V, and the cycle performance curve is obtained. The lithium ^- air battery based on [Ca ₂₀ Cd ₄ Al ₂₈ O ₆₄ ] ⁴⁺ :4e -material has a specific discharge capacity of 4538mAh·g ^-1 , an overpotential of 1.57V, and a cycle life of 120 cycles.

Example 6: Application of [Sr ₂ N] ⁺ :e -electron compound in lithium ^- air battery

Weigh 300mg Sr ₃ N ₂ into a quartz crucible, at the same time weigh 300mg metal Ti particles, place them on both ends of a high temperature tube furnace, evacuate to negative pressure, heat up to 1100 ° C, keep the temperature for 24 h, and the heating rate is 5 ° C/ min, after the calcination is completed, the furnace is cooled to obtain [Sr ₂ N] ^{+ :} e -electronic compound.

[Sr ₂ N] ⁺ : e ^- electronic compound powder is used as cathode catalyst material, CNT is used as conductive agent, PVA is used as binder, and the mass ratio of catalyst, conductive agent and binder is 3:6:1. The catalyst slurry was obtained by magnetic stirring in absolute ethanol until dispersed uniformly. The slurry was uniformly sprayed on the carbon cloth substrate with a spray gun, and vacuum dried at 60°C overnight to obtain a positive electrode sheet with a loading capacity of 5 mg·cm ^-2 .

An improved Swagelock mold was used, with the positive electrode sheet as the positive electrode, the metal lithium sheet as the negative electrode, the polyolefin porous membrane and the glass fiber membrane as the double-layer separator, and 10M LiTFSI/TEGDME as the electrolyte to assemble the lithium-air battery in an argon glove box.

The charge-discharge performance test of the lithium-air battery was carried out on the LAND battery test equipment. The battery was placed in an oxygen glove box with a water content of less than 0.1 ppm. Before the test, it was left standing in an oxygen atmosphere for 2 hours. The density was 300 mA·g ^-1 , and after the discharge was completed, the same-capacity charge was performed at the same current density, and the battery charge-discharge curve was obtained. The limited discharge specific capacity was 1000mAh·g ^-1 , the current density was 100mA·g ^-1 , the discharge cut-off voltage was 2.0V, and the cycle performance curve was obtained. The lithium ^- air battery based on [Sr ₂ N] ⁺ :e -material has a specific discharge capacity of 4285mAh·g ^-1 , an overpotential of 1.64V, and a cycle life of 134 cycles.

Example 7: Application of [Y ₂ Ti ₂ O ₆ ] ⁺ : 2e ^- electronic compound in lithium-air battery

Weigh 400mg of Y ₂ Ti ₂ O ₇ into a quartz crucible, put it into a high temperature tube furnace, evacuate to negative pressure, continuously feed 20% H ₂ /80% N ₂ gas mixture, heat up to 1500°C, and keep for 2h , the heating rate is 5°C/min, and the furnace is cooled after calcination to obtain [Y ₂ Ti ₂ O ₆ ] ^{+ :} 2e -electronic compound.

[Y ₂ Ti ₂ O ₆ ] ⁺ : 2e ^- electronic compound powder is used as cathode catalyst material, Super P is used as conductive agent, PVDF is used as binder, and the mass ratio of catalyst, conductive agent and binder is 3:6: The ratio of 1 was dispersed in absolute ethanol, and the catalyst slurry was obtained by magnetic stirring ^until the dispersion was homogeneous.

An improved Swagelock mold was used, with the positive electrode sheet as the positive electrode, the metal lithium sheet as the negative electrode, the polyolefin porous membrane and the glass fiber membrane as the double-layer separator, and 2M LiTFSI/TEGDME as the electrolyte, and the lithium-air battery was assembled in an argon glove box.

The charge-discharge performance test of the lithium-air battery was carried out on the LAND battery test equipment. The battery was placed in an oxygen glove box with a water content of less than 0.1 ppm. Before the test, it was left standing in an oxygen atmosphere for 2 hours. The density was 400 mA·g ^-1 , and after the discharge was completed, the battery was charged with equal capacity at the same current density to obtain the battery charge-discharge curve. The limited discharge specific capacity is 2000mAh·g ^-1 , the current density is 400mA·g ^-1 , the discharge cut-off voltage is 2.0V, and the cycle performance curve is obtained. The lithium ^- air battery based on [Y ₂ Ti ₂ O ₆ ] ⁺ : 2e -material has a specific discharge capacity of 3847mAh·g ^-1 , an overpotential of 1.73V, and a cycle life of 98 cycles.

Example 8: Application of [YEuTi ₂ O ₆ ] ⁺ :2e ^- electronic compound in lithium-air battery

Weigh 400mg YEuTi ₂ O ₇ into a quartz crucible, put it in a high-temperature tube furnace, evacuate to a negative pressure, continuously feed 20% H ₂ /80% N ₂ gas mixture, heat up to 1000 ° C, hold for 10 h, and heat up The rate is 5°C/min, and the furnace is cooled after calcination to obtain [YEuTi ₂ O ₆ ] ^{+ :} 2e -electron compound.

[YEuTi ₂ O ₆ ] ⁺ :2e ^- electronic compound powder is used as cathode catalyst material, BP 2000 is used as conductive agent, PTFE is used as binder, and the mass ratio of catalyst, conductive agent and binder is 3:6:1 Proportionally dispersed in absolute ethanol, magnetically stirred until dispersed uniformly to obtain catalyst slurry, uniformly sprayed the slurry on the aluminum mesh substrate with a spray gun, and vacuum dried at 60 °C overnight to obtain a positive electrode sheet with a loading capacity of 4 mg·cm ^-2 .

A modified Swagelock mold was used, with the positive electrode sheet as the positive electrode, the metal lithium sheet as the negative electrode, the polyolefin porous membrane and the glass fiber membrane as the double-layer separator, and 1M LiTFSI/DMSO as the electrolyte, and the lithium-air battery was assembled in an argon glove box.

The charge-discharge performance test of the lithium-air battery was carried out on the LAND battery test equipment. The battery was placed in an oxygen glove box with a water content of less than 0.1 ppm. Before the test, it was left standing in an oxygen atmosphere for 2 hours. The density was 150 mA·g ^-1 , and after the discharge was completed, the same capacity charge was performed at the same current density to obtain the battery charge-discharge curve. The limited discharge specific capacity is 900mAh·g ^-1 , the current density is 100mA·g ^-1 , the discharge cut-off voltage is 2.0V, and the cycle performance curve is obtained. The discharge ratio of Li-air battery based on [YEuTi ₂ O ₆ ] ⁺ :2e ^- The capacity reaches 4756mAh·g ^-1 , the overpotential is 1.52V, and the cycle life is 129 cycles.

Comparative Example 1: Application of Super P in Li-air Batteries

The cathode catalyst material in Example 1 was replaced with Super P, and other steps were the same as those in Example 1. A cathode sheet was prepared, and a lithium-air battery was assembled by the same method as in Example 1, and electrochemical tests were carried out. The discharge specific capacity, overpotential and cycle number of the battery are shown in Figure 3. It can be seen from the figure that the lithium-air battery has a discharge specific capacity of 1868mAh·g ^-1 , an overpotential of 1.89V, and a cycle life of 45 cycles.

Comparative Example 2: Application of Ca ₂₄ Al ₂₈ O ₆₆ in Li-air Batteries

The Ca ₂₄ Al ₂₈ O ₆₆ powder was used as the positive electrode catalyst material. The positive electrode sheet was prepared by the same method as in Example 1, the lithium-air battery was assembled, and the electrochemical test was carried out. The discharge specific capacity, overpotential and cycle number of the battery are shown in Figure 3. It can be seen from the figure that the lithium-air battery has a discharge specific capacity of 1354mAh·g ^-1 , an overpotential of 1.94V, and a cycle life of 21 cycles.

It should be noted that the present invention is not limited to the above-mentioned embodiments. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims (10)

1. Application of an electronic compound as a cathode catalyst material for a lithium-air battery. 2. the application of electronic compound according to claim 1 as lithium-air battery cathode catalyst material, it is characterized in that, the molecular formula of described electronic compound is: A _x By O _zn ^: _2ne- or C ₂ N ^: e- ; where A is a low-valent large-radius cation, B is a high-valent small-radius cation, and C is an alkaline earth metal cation. 3. The application of the electronic compound according to claim 2 as a cathode catalyst material for a lithium-air battery, wherein the low-valent large-radius cations include Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , La ³⁺ , Eu ³⁺ , Y ³⁺ , Sn ²⁺ or Cd ²⁺ , the high valence small radius cations include Ti ⁴⁺ , Si ⁴⁺ or Al ³⁺ , the alkaline earth metal cations include Ca ²⁺ , Sr ²⁺ or Ba ²⁺ . 4. the application of the electronic compound according to claim 2 as the cathode catalyst material of lithium-air battery, it is characterized in that, described A is the same cation or this cation is partially substituted by other one or more cations, the described B is the same cation or the cation is partially substituted by other one or more cations, and the C is the same cation or the cation is partially substituted by other one or more cations. 5. the application of the electronic compound according to claim 1 or 2 or 3 or 4 as the positive electrode catalyst material of lithium-air battery, it is characterized in that, described electronic compound is by precursor by direct high temperature reduction method, metal vapor reduction method or It is prepared by a hydrogen atmosphere reduction method, wherein the precursors include oxides containing free oxygen (A _{x By O z )} or alkaline earth metal low nitrides (C ₃ N ₂ ). 6. The application of the electronic compound according to claim 5 as a cathode catalyst material for a lithium-air battery, wherein the direct high-temperature reduction method comprises the steps of: placing the precursor in a carbon crucible, under an inert gas atmosphere The electronic compound is prepared by direct high temperature reduction, the reduction temperature is 900-1500°C, the reduction time is 8-24h, and the inert gas is nitrogen or argon. 7. The application of the electronic compound according to claim 5 as a positive electrode catalyst material for a lithium-air battery, wherein the metal vapor reduction method comprises the following steps: placing the precursor in a quartz crucible, and placing the precursor in a quartz crucible; The reducing agent metal is placed, and the electronic compound is obtained by reduction under the atmosphere of metal vapor generated by heating. The reduction temperature is 700-1100 °C, and the reduction time is 24-240 h. The reducing agent metal includes: Ca, Mg, Al or Ti. 8. The application of the electronic compound as claimed in claim 5 as a cathode catalyst material for a lithium-air battery, wherein the hydrogen atmosphere reduction method comprises the following steps: placing the precursor in a quartz crucible, under 20% H ₂ /80% N ₂ atmosphere to obtain the electronic compound, the reduction temperature is 1000～1500℃, and the reduction time is 2～10h. 9. the application of electronic compound according to claim 1 as lithium-air battery cathode catalyst material, is characterized in that, described application concrete method is as follows: (1) Take the electronic compound as the positive electrode catalyst material, disperse it in absolute ethanol together with the conductive agent and the binder, stir evenly to make a slurry, then spray the slurry on the substrate, and dry it to obtain a loading of 0.5 ~10 mg·cm ⁻² of positive electrode sheet. (2) Using the positive electrode sheet as the positive electrode, the metal lithium sheet as the negative electrode, the polyolefin porous film and the glass fiber film as the separator, adding electrolyte, and assembling a lithium-air battery in an argon glove box. 10. The application of the electronic compound according to claim 9 as a cathode catalyst material for a lithium-air battery, wherein the mass ratio of the electronic compound, the conductive agent and the binder is 3:6:1, and the The conductive agent includes Super P, Ketjen Balck (KB), Vulcan XC-72, Black Pearl (BP 2000) or CNT, the binder includes PTFE, PVDF or PVA; the substrate includes nickel foam, carbon paper, Carbon cloth, steel wire mesh or aluminum mesh; the electrolyte includes LiTFSI/TEGDME, LiCF ₃ SO ₃ /TEGDME, LiTFSI/DMSO, LiClO ₄ /DMSO or LiPF ₆ /EC:DMC[1:1(v/v) ], the concentration of the electrolyte is 0.1-10M.

Images