Gas diffusion electrode suitable for high-power discharge of zinc-air battery

Abstract

The invention belongs to the technical field of metal-air batteries, and discloses a gas diffusion electrode suitable for high-power discharge of a zinc-air battery and a preparation method and application of the gas diffusion electrode, and the gas diffusion electrode comprises a catalyst conductive backing layer, a catalyst layer loaded with a catalyst and a catalyst modification layer. The catalyst modification layer is an ionic liquid, positive ions of the ionic liquid are 1-butyl-3-methylimidazolium ions, and negative ions of the ionic liquid are bis (trifluoromethylsulfonyl) imide ions, hexafluorophosphate ions or tris (pentafluoroethyl) trifluorophosphate ions. The gas diffusion electrode can realize efficient oxygen mass transfer so as to significantly improve oxygen reduction reaction kinetics. According to the zinc air battery prepared by adopting the gas diffusion electrode, the polarization of the zinc air battery during high-power discharge can be reduced, the power density can be improved, discharge is performed under the current density of 200 mA cm < 2 >, the polarization of the zinc air battery is less than 0.75 V, and the power density is greater than 180 mW cm < 2 >.

Description

Technical Field

[0001] This invention belongs to the field of metal-air battery technology, and discloses a gas diffusion electrode suitable for high-power discharge of zinc-air batteries, its preparation method and application. Background Technology

[0002] Zinc-air batteries are metal-air electrochemical energy storage systems that use metallic zinc as the negative electrode and oxygen from the air as the positive electrode active material. These batteries possess advantages such as high theoretical energy density, safety and environmental friendliness, wide availability of materials, and low cost, making them a promising next-generation energy storage technology with broad application prospects in renewable energy storage and other fields. However, under high-power discharge conditions, battery polarization increases sharply, and the discharge voltage drops rapidly, making it difficult for the battery to maintain stable output energy. This seriously hinders the practical application of zinc-air batteries.

[0003] Studies have shown that oxygen mass transfer at the zinc-air cathode is a bottleneck limiting its high-power discharge performance. Specifically, during discharge, the oxygen reduction reaction occurs at the cathode of a zinc-air battery. This process relies on the structure of the gas diffusion electrode to achieve efficient oxygen mass transfer and electrochemical conversion. The mass transfer flux of oxygen in the gas diffusion electrode directly determines the battery's discharge capacity. During discharge, oxygen needs to be transported from the gas phase environment through the gas diffusion layer to the electrolyte-wetted three-phase interface and reduced at the catalytic sites. Under high-power discharge conditions, the increased current density leads to a significant increase in the oxygen consumption rate, while the oxygen flux in the gas diffusion electrode cannot meet the reaction requirements, thus forming a mass transfer bottleneck. This causes a rapid drop in the battery's operating voltage, resulting in a significant reduction in energy efficiency and cycle life. Therefore, it is necessary to solve the problem of limited oxygen mass transfer in the gas diffusion electrode and increase the oxygen flux so that the zinc-air battery can discharge effectively under high-power conditions.

[0004] To address the issue of limited oxygen mass transfer, current research mainly focuses on electrode structure optimization and interface control. In terms of structural design, improving the pore structure of the gas diffusion layer has been shown to improve oxygen transport pathways. Zhou et al. constructed a hierarchical porous carbon-based catalyst, which improved oxygen diffusion performance through the synergistic effect of multi-scale channels, resulting in reduced discharge polarization (Small, 2023, 19, 2302464). Similarly, Lee et al. reported a strategy for constructing the gas diffusion layer based on a three-dimensional graphene aerogel framework, which can form a continuous gas transport network, thereby reducing diffusion resistance (Membranes, 2022, 12, 1243). However, such structural optimization often relies on complex fabrication processes, and precise pore size control is difficult to achieve, thus limiting its effectiveness in improving the discharge performance of zinc-air batteries. Regarding interface control, adjusting the surface hydrophobicity of the gas diffusion electrode has been shown to help maintain gas-liquid balance and enhance mass transfer. Studies have shown that biomimetic hydrophobic coatings or fluorinated modified materials can enhance gas permeability and interfacial stability, thereby improving oxygen mass transfer (Small, 2025, 21, 2504245; Adv. Energy Mater., 2025, 15, 2404946). Although the above strategies can improve oxygen mass transfer at moderate current densities, they still face the problem of local oxygen deficiency under high-power discharge conditions. Therefore, further development of gas electrode diffusion electrode optimization strategies is needed to significantly improve mass transfer flux, thereby achieving stable discharge of zinc-air batteries under high-power conditions and advancing the practical application of zinc-air batteries. Summary of the Invention

[0005] This invention provides a gas diffusion electrode suitable for high-power discharge in zinc-air batteries. By modifying the surface of the gas diffusion electrode with an ionic liquid, the oxygen mass transfer flux is increased by improving the gas-liquid interface characteristics. Specifically, ionic liquids, as low-vapor-pressure salt liquids composed of organic cations and inorganic or organic anions, possess excellent chemical stability. Some ionic liquids have high oxygen solubility, providing a more favorable oxygen transfer environment at the gas-liquid interface and increasing oxygen flux. Modifying the gas diffusion electrode with an ionic liquid, without altering the electrode structure, allows the formation of a stable ionic liquid film at the gas-liquid interface, enhancing oxygen transport capacity and thus increasing oxygen flux to meet the demands of high-power discharge.

[0006] This invention provides a gas diffusion electrode suitable for high-power discharge of zinc-air batteries and its preparation method, solving the problem that existing zinc-air batteries cannot discharge at high power.

[0007] This invention provides a gas diffusion electrode suitable for high-power discharge of zinc-air batteries, comprising a catalyst conductive backing layer, a catalyst layer with a supported catalyst, and a catalyst modification layer. The catalyst modification layer is characterized by being an ionic liquid, wherein the cation is 1-butyl-3-methylimidazolium ion, and the anion is bis(trifluoromethanesulfonyl)imide ion, hexafluorophosphate, or tris(pentafluoroethyl)trifluorophosphate. The amount of ionic liquid used is 5-20 wt% of the catalyst mass in the catalyst layer.

[0008] In some more preferred embodiments, the ionic liquid is preferably 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt.

[0009] In some preferred embodiments, the catalyst in the catalyst layer is cobalt tetroxide, and the catalyst loading is 0.50~2.0 mg / cm³. −2 .

[0010] In some preferred embodiments, the catalyst backing layer is a hydrophobic carbon fiber composite paper, optionally with a thickness of 150-220 μm, optionally with a water contact angle of 130-150° at 25°C, and optionally with a porosity of 60%-85%. Preferably, the thickness is 190 μm, and the water contact angle at 25°C is 140°. o .

[0011] Secondly, the present invention provides a method for preparing a gas diffusion electrode suitable for high-power discharge of zinc-air batteries, the method comprising the following steps:

[0012] a) Disperse the catalyst in ethanol to prepare a catalyst slurry of 30-50 wt%;

[0013] b) Drop the slurry onto the catalyst backing layer to achieve a loading of 0.50–2.0 mg cm⁻¹. −2 Then dry at 60°C;

[0014] c) Disperse the ionic liquid in ethanol to prepare a 5 wt% solution;

[0015] d) The ionic liquid solution is dropped onto the surface of the catalyst layer to a loading of 5-20 wt% of the catalyst mass, and then dried at 60°C to obtain the gas diffusion electrode.

[0016] Thirdly, the present invention provides a zinc-air battery, which includes an alkaline electrolyte, a zinc negative electrode, and the gas diffusion electrode.

[0017] In some preferred embodiments, the alkaline electrolyte comprises potassium hydroxide, preferably a combination of potassium hydroxide and zinc acetate.

[0018] Fourthly, the present invention provides an application of the gas diffusion electrode described above in a zinc-air battery.

[0019] The beneficial effects of this invention are as follows:

[0020] This invention provides a gas diffusion electrode suitable for high-power discharge in zinc-air batteries. By introducing an ionic liquid layer onto the surface of the gas diffusion electrode, the dissolution and interfacial transport rates of oxygen can be significantly improved, effectively alleviating mass transfer limitations during high-power discharge. The low volatility and high stability of the ionic liquid ensure the persistence of the interfacial layer during discharge, making it difficult for it to be replaced or diluted by the electrolyte, thus maintaining a stable reaction interface. Furthermore, the preparation process is simple, compatible with existing electrode systems, and does not alter the overall structure of the gas diffusion electrode. These advantages enable the ionic liquid-modified gas diffusion electrode to effectively reduce polarization under high-current discharge, improve energy efficiency, and enhance battery cycle stability.

[0021] The gas diffusion electrode prepared according to the embodiments of the present invention can be used in zinc-air batteries at 200 mA cm⁻¹. −2 Discharging at a current density, the zinc-air battery exhibits polarization less than 0.75 V and a power density greater than 180 mW / cm². −2 . Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the gas diffusion electrode of this application. Detailed Implementation

[0023] The present invention will be illustrated by specific examples below. These examples are provided to better understand the present invention and are not intended to limit the scope of the present invention.

[0024] Example 1

[0025] 1) Disperse the cobalt tetroxide catalyst in ethanol to prepare a 30 wt% catalyst slurry;

[0026] 2) The slurry is dropwise added to the catalyst backing layer, wherein the porosity of the catalyst backing layer is 75% and the catalyst loading is 1.0 mg cm⁻¹. −2 The electrode sheets are then dried at 60°C.

[0027] 3) Disperse 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt in ethanol to prepare a 5 wt% solution;

[0028] 4) The ionic liquid solution is dropped onto the surface of the catalyst layer to achieve a loading of 10 wt% of the catalyst mass. After drying at 60°C, the desired product is obtained. Figure 1 The gas diffusion electrode shown.

[0029] The gas diffusion electrode prepared above was used as the positive air electrode, and metallic zinc (500 μm thick) was used as the negative electrode. The electrolyte was 6.0 mol L⁻¹. −1 The potassium hydroxide solution contains 0.20 mol / L −1 A zinc-air battery (without a battery separator) was assembled using an alkaline electrolyte of zinc acetate (1.5 mL). A linear voltammetric scan was performed on the battery at 25°C (at ambient pressure, without external air or oxygen supply), specifically scanning from the open-circuit voltage towards lower voltages at a scan rate of 10 mV / s. −1 The scan cutoff voltage is 0.3 V.

[0030] The results showed that at 200 mA cm −2 At a discharge current density of 0.65V, the zinc-air battery exhibits polarization of 203 mW / cm². −2 .

[0031] Comparative Example 1: The effect of having or not having an ionic liquid modification layer

[0032] Based on Example 1, no ionic liquid modification layer is added in step 3), while the other components and preparation process remain the same as in Example 1.

[0033] Discharge tests were performed under the same conditions as in Example 1. The gas diffusion electrode prepared in Comparative Example 1, when applied in a zinc-air battery, can achieve a discharge rate of 200 mA cm⁻¹. −2 Discharging at a current density of 0.99 V, the zinc-air battery exhibits polarization of 132 mW / cm². −2 .

[0034] The experimental results are as follows:

[0035] Table 1. Effect of the presence or absence of ionic liquids on battery performance

[0036]

[0037] Conclusion Analysis

[0038] As can be seen from Example 1 and Comparative Example 1 above, the presence or absence of an ionic liquid-modified gas diffusion electrode has a significant impact on the polarization of the zinc-air battery under high-power discharge. In Comparative Example 1, which does not contain an ionic liquid, the oxygen mass transfer rate cannot keep up with the reaction rate under high-current discharge conditions, resulting in greater polarization during discharge and limiting its application under high-power conditions.

[0039] Example 2: Effects of Different Types of Ionic Liquids

[0040] Based on Example 1, the ionic liquid in step 3) is changed, replacing 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt in Example 1 with 1-butyl-3-methylimidazolium hexafluorophosphate, while the other components and preparation process remain the same as in Example 1.

[0041] Discharge tests were performed under the same conditions as in Example 1. The gas diffusion electrode prepared in this example, when applied in a zinc-air battery, can achieve a discharge rate of 200 mA cm⁻¹. −2 Discharging at a current density of 0.71 V, the zinc-air battery exhibits polarization of 0.71 V and a corresponding power density of 188 mW / cm². −2 .

[0042] Example 3: Effects of Different Types of Ionic Liquids

[0043] Based on Example 1, the ionic liquid in step 3) is changed, replacing 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt in Example 1 with 1-butyl-3-methylimidazolium tri(pentafluoroethyl)trifluorophosphate, while other components and preparation process remain the same as in Example 1.

[0044] Discharge tests were performed under the same conditions as in Example 1. The gas diffusion electrode prepared in this example, when applied in a zinc-air battery, can achieve a discharge rate of 200 mA cm⁻¹. −2 Discharging at a current density of 0.70 V, the zinc-air battery exhibits polarization of 0.70 V and a corresponding power density of 191 mW / cm². −2 .

[0045] Comparative Example 2: Effects of Different Types of Ionic Liquids

[0046] Based on Example 1, the type of ionic liquid in step 3) is changed, replacing 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt in Example 1 with 1-butyl-3-methylimidazolium acetate, while the other components and preparation process remain the same as in Example 1.

[0047] Discharge tests were performed under the same conditions as in Example 1. The gas diffusion electrode prepared by this method, when applied in a zinc-air battery, can achieve a discharge rate of 200 mA cm⁻¹. −2 Discharging at a current density of 1.2 V, the zinc-air battery exhibits polarization at 1.2 V and a corresponding power density of 97 mW / cm². −2 .

[0048] Comparative Example 3: Effects of Different Types of Ionic Liquids

[0049] Based on Example 1, the type of ionic liquid in step 3) is changed, replacing 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt in Example 1 with 1-hexadecyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, while other components and preparation processes remain the same as in Example 1.

[0050] Discharge tests were performed under the same conditions as in Example 1. The gas diffusion electrode prepared by this method, when applied in a zinc-air battery, can achieve a discharge rate of 200 mA cm⁻¹. −2 Discharging at a current density of 1.3 V, the zinc-air battery exhibits polarization at 1.3 V and a corresponding power density of 78 mW / cm². −2 .

[0051] Table 2. Effect of Ionic Liquid Type on Battery Performance

[0052]

[0053] Conclusion Analysis

[0054] As can be seen from Examples 1-3, Comparative Examples 2 and 3 above, when the ionic liquid modification layers 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 1-butyl-3-methylimidazolium hexafluorophosphate, and 1-butyl-3-methylimidazolium tri(pentafluoroethyl)trifluorophosphate of the present invention are used, the gas diffusion electrode prepared is applied to a zinc-air battery. Since the solubility of oxygen in the ionic liquid is tens of times that in water, this advantage can significantly improve the oxygen mass transfer at the positive electrode and reduce polarization under high current discharge. Among these, oxygen has the highest solubility in 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt. Using 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, gas diffusion electrodes can be applied to zinc-air batteries at 200 mA cm⁻¹. −2 Discharging at a current density of 0.65 V with a polarization of 203 mW / cm², the power density is 203 mW / cm². −2 Therefore, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt is the optimal ionic liquid modifier.

[0055] Conversely, the addition of 1-ethyl-3-methylimidazolium acetate does not reduce the polarization of the zinc-air battery under high-power discharge conditions. This is because 1-ethyl-3-methylimidazolium acetate is a hydrophilic ionic liquid, which would make the gas diffusion electrode hydrophilic, causing flooding and deteriorating mass transfer. When 1-hexadecyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt is added, the solubility of oxygen in it does not increase significantly, and the viscosity of the ionic liquid is too high, which would further slow down oxygen diffusion and increase polarization under high-power discharge conditions.

[0056] Example 4: Effect of Ionic Liquid Content

[0057] Based on Example 1, the mass fraction of the catalyst in step 4) was changed from 10 wt% in Example 1 to 20 wt%, while the other components and preparation process remained the same as in Example 1.

[0058] Discharge tests were performed under the same conditions as in Example 1. The gas diffusion electrode prepared by this method, when applied in a zinc-air battery, can achieve a discharge rate of 200 mA cm⁻¹. −2 Discharging at a current density of 0.72 V, the zinc-air battery exhibits polarization of 0.72 V and a corresponding power density of 186 mW / cm². −2 .

[0059] Example 5: Effect of Ionic Liquid Content

[0060] Based on Example 1, the mass fraction of ionic liquid in the catalyst in step 4) was changed from 10 wt% in Example 1 to 5 wt%, while other components and preparation processes remained the same as in Example 1.

[0061] Discharge tests were performed under the same conditions as in Example 1. The gas diffusion electrode prepared by this method, when applied in a zinc-air battery, can achieve a discharge rate of 200 mA cm⁻¹. −2 Discharging at a current density of 0.73 V, the zinc-air battery exhibits polarization of 0.73 V and a corresponding power density of 184 mW / cm². −2 .

[0062] Comparative Example 4: Effect of Ionic Liquid Content

[0063] Based on Example 1, the mass fraction of the catalyst in step 4) of the ionic liquid was changed from 10 wt% in Example 1 to 1 wt%, while the other components and preparation process remained the same as in Example 1.

[0064] Discharge tests were performed under the same conditions as in Example 1. The gas diffusion electrode prepared by this method, when applied in a zinc-air battery, can achieve a discharge rate of 200 mA cm⁻¹. −2 Discharging at a current density of 0.98 V, the zinc-air battery exhibits polarization of 0.98 V and a corresponding power density of 134 mW / cm². −2 .

[0065] Comparative Example 5: Effect of Ionic Liquid Content

[0066] Based on Example 1, the mass fraction of ionic liquid in the catalyst in step 4) was changed from 10 wt% in Example 1 to 30 wt%, while other components and preparation processes remained the same as in Example 1.

[0067] Discharge tests were performed under the same conditions as in Example 1. The gas diffusion electrode prepared by this method, when applied in a zinc-air battery, can achieve a discharge rate of 200 mA cm⁻¹. −2 Discharging at a current density of 1.1 V, the zinc-air battery exhibits polarization at 1.1 V and a corresponding power density of 110 mW / cm². −2 .

[0068] The experimental results are as follows:

[0069] Table 3. Effect of ionic liquid content on battery performance

[0070]

[0071] Conclusion Analysis

[0072] As can be seen from Examples 1, 4-5, and Comparative Examples 4-5 above, the concentration of the ionic liquid has a significant impact on the discharge polarization of the zinc-air battery. When the amount of ionic liquid is low, the electrode surface modification is insufficient, and the improvement effect on oxygen mass transfer is limited, thus significantly increasing electrochemical polarization. For example, when the amount of ionic liquid is 1 wt%, the zinc-air battery exhibits a significant increase in electrochemical polarization at 200 mA cm⁻¹. −2 The polarization during discharge at the specified current density is 0.99 V. Preferably, when the amount of ionic liquid added is 10 wt%, the battery discharge polarization decreases to 0.65 V, exhibiting optimal discharge performance. When the amount of ionic liquid added increases to 20 wt%, the battery discharge polarization is 0.73 V, which is still lower than the comparative ratio without added ionic liquid, indicating that an appropriate amount of ionic liquid is beneficial for increasing oxygen flux.

[0073] However, when the amount of ionic liquid exceeds the preferred range of this application, for example, increasing to 30 wt%, the effective mass transfer path of oxygen in the electrode is prolonged due to the low oxygen diffusion coefficient of the ionic liquid itself and the significant increase in the thickness of the modification layer, resulting in a limitation of the overall mass transfer process. Under these conditions, the zinc-air battery at 200 mA cm⁻¹... −2 The discharge polarization voltage rises to about 1.1 V under current density, and the discharge performance deteriorates significantly, which can no longer meet the requirements for practical application.

[0074] Comparative Example 6: The effect of ionic liquids as electrolyte additives

[0075] Based on Example 1, the method of adding the ionic liquid in steps 3) and 4) was adjusted. The ionic liquid was added directly to the alkaline electrolyte at 10 wt% of the electrolyte mass. Except for the above changes, the remaining composition and electrode preparation process remained consistent with Example 1. Discharge tests were conducted under the same conditions as in Example 1.

[0076] Because the selected ionic liquid is insoluble in the aqueous alkaline electrolyte, this addition method leads to significant phase separation in the electrolyte system, obstructing ion transport pathways and reducing the effective reaction area at the gas-solid-liquid three-phase interface. Therefore, the zinc-air battery assembled using this electrolyte exhibits a discharge current density far below 200 mAcm⁻¹ during linear voltammetry scanning. −2 It is impossible to obtain zinc-air batteries with excellent electrical performance for use.

[0077] Comparative Example 7: Effect of High-Temperature Treatment on Ionic Liquid Modified Layers

[0078] Based on Example 1, the treatment method of the ionic liquid modification layer in the gas diffusion electrode was modified. Specifically, the gas diffusion electrode after ionic liquid modification was heat-treated in an atmosphere of 350 °C for 2 h. Except for the above changes, the remaining composition and electrode preparation process were consistent with Example 1. Discharge tests were performed under the same conditions as in Example 1.

[0079] The zinc-air battery leaks under operating conditions due to the decomposition and structural damage of the ionic liquid at high temperatures, coupled with changes in wettability in the gas diffusion electrode caused by heat treatment. Consequently, during linear voltammetric scanning tests, excessive polarization prevents the acquisition of effective power density data for the zinc-air battery.

[0080] Example 6: Effect of catalyst loading

[0081] Based on Example 1, the catalyst loading in step 2) was changed from 1.0 mg / cm³ in Example 1. −2 Change to 0.5 mg cm −2 Other components and preparation processes remain consistent with those in Example 1.

[0082] The gas diffusion electrode prepared by this method can be used in zinc-air batteries at 200 mA cm⁻¹. −2 Discharging at a current density of 0.79 V, the zinc-air battery exhibits polarization of 172 mW / cm². −2 .

[0083] Example 7: Effect of catalyst loading

[0084] Based on Example 1, the catalyst loading in step 2) was changed from 1.0 mg / cm³ in Example 1. −2 Change to 2.0 mg cm −2 Other components and preparation processes remain consistent with those in Example 1.

[0085] Discharge tests were performed under the same conditions as in Example 1. The gas diffusion electrode prepared by this method, when applied in a zinc-air battery, can achieve a discharge rate of 200 mA cm⁻¹. −2 Discharging at a current density of 0.67 V, the zinc-air battery exhibits polarization of 0.67 V and a power density of 196 mW / cm². −2 .

[0086] Example 8: Effect of catalyst backing porosity

[0087] Based on Example 1, the type of catalyst backing layer in step 2) is changed from 75% porosity in Example 1 to 60%, while other components and preparation processes remain the same as in Example 1.

[0088] Discharge tests were performed under the same conditions as in Example 1. The gas diffusion electrode prepared by this method, when applied in a zinc-air battery, can achieve a discharge rate of 200 mA cm⁻¹. −2 Discharging at a current density of 0.82 V, the zinc-air battery exhibits polarization of 164 mW / cm². −2 .

[0089] Example 9: Effect of catalyst backing porosity

[0090] Based on Example 1, the type of catalyst backing layer in step 2) is changed from 75% porosity in Example 1 to 85%, while other components and preparation processes remain the same as in Example 1.

[0091] Discharge tests were performed under the same conditions as in Example 1. The gas diffusion electrode prepared by this method, when applied in a zinc-air battery, can achieve a discharge rate of 200 mA cm⁻¹. −2 Discharging at a current density of 0.74 V, the zinc-air battery exhibits polarization of 0.74 V and a power density of 180 mW / cm². −2 .

Claims

1. A gas diffusion electrode suitable for high power discharge of zinc-air battery, comprising a catalyst conductive backing layer and a catalyst layer; on the side of the catalyst layer away from the catalyst conductive backing layer, a catalyst modification layer is provided; the material of the catalyst modification layer comprises an ionic liquid; the ionic liquid is composed of an anion and a cation; the cation comprises 1-butyl-3-methylimidazolium ion; the anion comprises bis(trifluoromethylsulfonyl)imide ion, hexafluorophosphate or tris(pentafluoroethyl)trifluorophosphate.

2. The gas diffusion electrode suitable for high power discharge of a zinc-air battery according to claim 1, wherein the ionic liquid is 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide salt.

3. A gas diffusion electrode suitable for high power discharge of a zinc-air battery according to claim 1 or 2, characterized in that the amount of the ionic liquid is 5-20 wt% of the mass of the catalyst in the catalyst layer, preferably 10 wt%.

4. The gas diffusion electrode suitable for high power discharge of a zinc-air battery according to claim 1, wherein The catalyst in the catalyst layer is tricobalt tetroxide; the loading of the catalyst is 0.50-2.0 mg cm −2 .

5. The gas diffusion electrode suitable for high power discharge of a zinc-air battery according to claim 1, wherein the catalyst backing layer is a hydrophobic carbon fiber composite paper; optionally, the thickness is 150-220 μm, optionally, the water contact angle at 25°C is 130-150°, and optionally, the porosity is 60-85%.

6. A method for preparing the gas diffusion electrode suitable for high power discharge of zinc-air battery according to any one of claims 1-5, comprising the following steps: 1) dispersing the catalyst in ethanol to prepare a catalyst slurry with a catalyst mass fraction of 30-50 wt%; 2) The slurry is dropped onto the catalyst backing layer to give a loading of 0.50 to 2.0 mg cm −2 , which is then dried at 60°C to form a catalyst layer; 3) dispersing the ionic liquid in ethanol to prepare a solution with an ionic liquid mass fraction of 5 wt%; 4) dropping the ionic liquid solution onto the surface of the catalyst layer to form a catalyst modification layer, and the loading amount of the ionic liquid is 5-20 wt% of the mass of the catalyst; after drying at 60°C, the gas diffusion electrode is obtained, and the drying temperature should not exceed 100°C.

7. A zinc-air battery comprising an alkaline electrolyte, a zinc negative electrode and the gas diffusion electrode according to any one of claims 1-5.

8. Use of the gas diffusion electrode according to any one of claims 1-5 in a zinc-air battery.

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