A prussian blue composite electrode and a preparation method and application thereof

Abstract

The application provides a prussian blue composite electrode and a preparation method and application thereof, and belongs to the technical field of energy storage batteries, and comprises a prussian blue layer and a zeolite layer covering the surface of the prussian blue layer; the preparation method of the prussian blue composite electrode comprises the following steps: S1, mixing manganese-based prussian blue, a conductive agent and a binder according to a mass ratio of 92-96:3-7:1-5, and coating the mixture on a current collector by using a dry coating process to obtain a prussian blue layer; S2, crushing and dehydrating a zeolite to obtain a zeolite powder; S3, mixing the zeolite powder, the conductive agent and the binder according to a mass ratio of 92-96:3-7:1-5, and coating the mixture on the surface of the prussian blue layer by using a dry coating process to form a zeolite layer completely wrapping the prussian blue layer, so that the prussian blue composite electrode is obtained. The application solves the problems of short cycle life and poor rate performance of the prussian blue composite electrode in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of energy storage battery technology, specifically relating to a Prussian blue composite electrode, its preparation method, and its application. Background Technology

[0002] With the increasing global demand for clean energy and energy storage technologies, sodium-ion batteries, which are abundant in resources, low in cost, and highly safe, are considered an important development direction in the field of large-scale energy storage. In the composition of sodium-ion batteries, the cathode material is crucial, directly affecting the battery's cost, performance, and sustainable development prospects.

[0003] Among numerous cathode materials, Prussian blue-based materials are considered ideal candidates for sodium-ion battery cathodes due to their open framework structure and suitability for large-size sodium ion transport. However, Prussian blue materials face two major challenges. First, they exhibit poor cycle stability. The Prussian blue structure contains water of crystallization, which precipitates from the crystal lattice during charge and discharge, disrupting structural integrity. For manganese-based Prussian blue, the Jahn-Teller effect of trivalent manganese induces lattice distortion, while divalent manganese ions are easily dissolved and lost in the electrolyte, collectively leading to loss of active material and rapid capacity decay. Second, they suffer from poor rate performance. Prussian blue materials have low conductivity, and the presence and changes in water of crystallization hinder the rapid transport of sodium ions in the bulk phase and at the interface.

[0004] Currently, existing improvement methods, such as element doping and carbon encapsulation, can partially improve conductivity or alleviate single problems, but they are insufficient to effectively isolate electrolyte corrosion, suppress ion dissolution, and manage the release of water of crystallization and interfacial side reactions within the same structure. Therefore, there is an urgent need for an electrode structure that can solve multiple problems mentioned above. Summary of the Invention

[0005] Based on the above-mentioned technical problems, the purpose of this invention is to provide a Prussian blue composite electrode, its preparation method and application, to solve the problems of short cycle life and poor rate performance of Prussian blue composite electrodes in the prior art.

[0006] The specific technical solution is as follows:

[0007] A method for preparing a Prussian blue composite electrode includes the following steps:

[0008] S1: Mix manganese-based Prussian blue, conductive agent and binder in a mass ratio of 92~96:3~7:1~5, and coat it onto the current collector using a dry coating process to obtain a Prussian blue layer.

[0009] S2: Crush and dehydrate the zeolite to obtain zeolite powder;

[0010] S3: Mix zeolite powder, conductive agent and binder in a mass ratio of 92~96:3~7:1~5, and apply the mixture to the surface of the Prussian blue layer using a dry coating process to form a zeolite layer that completely covers the Prussian blue layer, thereby obtaining the Prussian blue composite electrode.

[0011] In addition, the method for preparing a Prussian blue composite electrode in the above-mentioned technical solution provided by the present invention may also have the following additional technical features:

[0012] In the above technical solution, the ratio of the thickness of the zeolite layer to the thickness of the Prussian blue layer is 1:5~20.

[0013] In the above technical solution, the manganese-based Prussian blue formula is Na. d Mn 1-t M t [Fe(CN)6] h ·zH2O, where M is selected from at least one of Fe, Co, Ni, Cu, Zn, and Cr, 1.7≤d≤2, 0.4≤t≤0.6, 0.9≤h≤1, and 2≤z≤4.

[0014] In the above technical solution, the general formula for zeolite is A. (x / q) [(AlO2) x (SiO2) y ]·nH2O, where A is at least one of Ca, Na, K, Ba, and Sr, where 2≤y / x≤5, and q is the charge number of A.

[0015] In the above technical solution, in steps S1 and S3, the conductive agent is acetylene black, carbon nanotubes, carbon fibers or graphene, and the binder is polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene or perfluoroethylene propylene.

[0016] In the above technical solution, in step S2, the zeolite is first pulverized to 50-200 nanometers using a sand milling method, and then the pulverized zeolite is dehydrated. The dehydration temperature is 300℃-500℃, the dehydration time is 1-5 hours, and the dehydration atmosphere is air or oxygen. After dehydration, the transport rate of sodium ions can be improved, and the crystal water released during the charging and discharging of Prussian blue can be absorbed, thereby improving the rate performance and cycle performance.

[0017] A Prussian blue composite electrode includes: a Prussian blue layer and a zeolite layer covering the surface of the Prussian blue layer;

[0018] Application of a Prussian blue composite electrode in sodium-ion batteries.

[0019] The Prussian blue composite electrode, its preparation method, and its application, as described in this invention, offer the following advantages compared to existing technologies:

[0020] By coating the Prussian blue layer with a zeolite layer, two major problems—poor cycle stability and inadequate rate performance—were simultaneously solved. On one hand, the zeolite layer acts as a physical barrier, preventing direct contact between the Prussian blue layer and the electrolyte, effectively inhibiting electrolyte corrosion of the Prussian blue and dissolution of active metal ions, thus ensuring a long cycle life for the electrode. On the other hand, the zeolite layer itself has excellent ionic conductivity, promoting sodium ion transport and adsorbing the water of crystallization released during the charging and discharging process of Prussian blue, reducing the damage of water molecules to the electrolyte interface, stabilizing the interface environment, and thus significantly improving rate performance.

[0021] The preparation method of the present invention has the characteristics of simple process, low cost, short cycle, low energy consumption and suitability for industrial production. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the Prussian blue composite electrode prepared in Example 1 of the present invention;

[0023] Figure 2 The charge-discharge curve of the Prussian blue composite electrode prepared in Example 1 of this invention;

[0024] Figure 3 The rate performance diagram of the Prussian blue composite electrode prepared in Example 1 of this invention;

[0025] Figure 4 The cycle life diagram is shown for the Prussian blue composite electrode prepared in Example 1 of this invention.

[0026] Figure 5 The rate performance diagram shows the Prussian blue composite electrode prepared in Comparative Example 1 of this invention.

[0027] Figure 6 The cycle life diagram shows the Prussian blue composite electrode prepared in Comparative Example 1 of this invention. Detailed Implementation

[0028] The following are specific implementation cases and appendices. Figure 1-6 The present invention will be further described, but the present invention is not limited to these embodiments.

[0029] A Prussian blue composite electrode includes: a Prussian blue layer and a zeolite layer covering the surface of the Prussian blue layer;

[0030] The preparation method of the Prussian blue composite electrode includes the following steps:

[0031] S1: Mix manganese-based Prussian blue, conductive agent and binder in a mass ratio of 92~96:3~7:1~5, and coat it onto the current collector using a dry coating process to obtain a Prussian blue layer.

[0032] S2: Crush and dehydrate the zeolite to obtain zeolite powder;

[0033] S3: Mix zeolite powder, conductive agent and binder in a mass ratio of 92~96:3~7:1~5, and apply the mixture to the surface of the Prussian blue layer using a dry coating process to form a zeolite layer that completely covers the Prussian blue layer, thereby obtaining the Prussian blue composite electrode.

[0034] A dry coating process is used to coat the current collector with Prussian blue, and fibrous polytetrafluoroethylene is used as a binder. The dry processing of the electrode makes the electrode denser, which can improve the energy density, facilitate sodium ion diffusion, and inhibit the corrosion of the material by the electrolyte.

[0035] A zeolite layer is coated onto the current collector using a dry coating process, and fibrous polytetrafluoroethylene is used as a binder. The dry processing of the electrode results in a denser electrode, which is conducive to sodium ion diffusion and better protects the Prussian blue material.

[0036] By doping with manganese, the Jahn-Teller effect is suppressed, the crystal structure of manganese-based Prussian blue is stabilized, and the electronic conductivity is improved. The coating of the zeolite layer promotes the transport of sodium ions and inhibits the corrosion of Prussian blue materials by electrolyte, thereby improving rate performance and cycle life.

[0037] By coating the Prussian blue layer with a zeolite layer, two major problems—poor cycle stability and inadequate rate performance—were simultaneously solved. On one hand, the zeolite layer acts as a physical barrier, preventing direct contact between the Prussian blue layer and the electrolyte, effectively inhibiting electrolyte corrosion of the Prussian blue and dissolution of active metal ions, thus ensuring a long cycle life for the electrode. On the other hand, the zeolite layer itself has excellent ionic conductivity, promoting sodium ion transport and adsorbing the water of crystallization released during the charging and discharging process of Prussian blue, reducing the damage of water molecules to the electrolyte interface, stabilizing the interface environment, and thus significantly improving rate performance.

[0038] The preparation method of the present invention has the characteristics of simple process, low cost, short cycle, low energy consumption and suitability for industrial production.

[0039] In an embodiment of the present invention, the ratio of the thickness of the zeolite layer to the thickness of the Prussian blue layer is 1:5 to 20.

[0040] Within a zeolite layer thickness to Prussian blue layer thickness ratio of 1:5 to 20, an optimized balance of capacity, rate performance, and cycle life can be achieved.

[0041] The zeolite layer completely covers the Prussian blue layer, effectively inhibiting the corrosion of the Prussian blue material by the electrolyte. Complete coverage means that the surface and edges of the Prussian blue are covered by zeolite.

[0042] In an embodiment of the present invention, the manganese-based Prussian blue formula is Na. d Mn 1-t M t [Fe(CN)6] h ·zH₂O, where M is selected from at least one of Fe, Co, Ni, Cu, Zn, and Cr, 1.7≤d≤2, 0.4≤t≤0.6, 0.9≤h≤1, and 2≤z≤4. Under these conditions, the product's capacity, rate performance, and cycle life achieve an optimized balance.

[0043] Specifically, M contains Fe, and Fe doping can improve the electronic conductivity of manganese-based Prussian blue materials, thereby improving rate performance. In addition, Fe doping can effectively suppress the Jahn-Teller effect and improve cycle life.

[0044] Na d Mn 1-t M t [Fe(CN)6] h The preparation method of zH2O is as follows: It is prepared by co-precipitation, specifically:

[0045] Prepare solution A containing Na₄Fe(CN)₆ and solution B containing Mn. 2+ and M 2+ Solution B is mixed with the solution to produce manganese Prussian blue. The reaction temperature is 40℃~80℃. After the reaction is completed, the mixture is centrifuged and dried to obtain manganese Prussian blue material powder.

[0046] In an embodiment of the present invention, the general formula for zeolite is A. (x / q) [(AlO2) x (SiO2) y ]·nH2O, where A is at least one of Ca, Na, K, Ba, and Sr, where 2≤y / x≤5, and q is the charge number of A.

[0047] Specifically, the zeolite is a natural zeolite, which has the advantages of good structural stability and low price. The natural zeolite is selected from at least one of clinoptilolite, mordenite, zeolite and flaky zeolite.

[0048] The zeolite coating can block the interfacial contact between the Prussian blue layer and the electrolyte, thereby inhibiting the corrosion of the Prussian blue material by the electrolyte and improving cycle life. At the same time, the zeolite layer has sodium ion conductivity, which promotes the transport of sodium ions and thus improves rate performance.

[0049] In the embodiments of the present invention, in steps S1 and S3, the conductive agent is acetylene black, carbon nanotubes, carbon fibers or graphene, and the binder is polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene or perfluoroethylene propylene.

[0050] In an embodiment of the present invention, in step S2, the zeolite is first pulverized to 50-200 nanometers using a sand milling method, and then the pulverized zeolite is dehydrated. The dehydration temperature is 300℃-500℃, the dehydration time is 1-5 hours, and the dehydration atmosphere is air or oxygen. After dehydration, the transport rate of sodium ions can be improved, and the crystal water released during the charging and discharging of Prussian blue can be absorbed, thereby improving the rate performance and cycle performance.

[0051] Application of a Prussian blue composite electrode in sodium-ion batteries.

[0052] Example 1: Using sodium ferrocyanide, manganese sulfate, copper sulfate, ferrous sulfate, and sodium citrate as precursors, at 60 °C... o Manganese-based Prussian blue Na was obtained by co-precipitation reaction at C. 1.72 Mn 0.56 Fe 0.31 Cu 0.13 [Fe(CN)6] 0.95 ·2.45H2O.

[0053] The prepared manganese-based Prussian blue, carbon nanotubes, and polytetrafluoroethylene were mixed in a weight ratio of 94:5:1. The polytetrafluoroethylene was fiberized by shear dispersion. The mixed powder was then coated onto an aluminum current collector using a dry method to obtain a Prussian blue layer.

[0054] Natural clinoptilolite Na8[Al8Si 40 O 96 ]·39H2O was used for sand milling to obtain D 50 The particles were 100 nm in size and then dehydrated at 400 °C for 2 hours in air to obtain dehydrated clinoptilolite. The above zeolite, carbon nanotubes, and polytetrafluoroethylene (PTFE) were mixed in a weight ratio of 94:5:1. The PTFE was fiberized by shear dispersion. The mixed powder was then dry-coated onto a Prussian blue layer to obtain a Prussian blue composite electrode. The structure of the composite electrode is as follows... Figure 1 As shown.

[0055] Testing revealed that the thickness ratio of the zeolite layer to the Prussian blue layer was 1:10. Using the Prussian blue composite electrode prepared in this embodiment as the positive electrode, metallic sodium as the negative electrode, glass fiber as the separator, and a 1 M NaPF6 propylene carbonate / ethyl methyl carbonate solution as the electrolyte, along with 4% by weight of fluoroethylene carbonate, a button cell was assembled. Charge-discharge tests were conducted at a voltage range of 2–4 V, 0.1C, and 1C = 150 mA / g. The capacity was 135.4 mAh / g. (See [link to relevant documentation]). Figure 2 At 10C, the capacity retention rate was 86.0% compared to 0.1C. (See...) Figure 3 After 200 cycles at 5C, the capacity retention was 93.9%. Figure 4 .

[0056] Example 2: Using sodium ferrocyanide, manganese sulfate, zinc sulfate, ferrous sulfate, and sodium citrate as precursors, at 60 °C... o Manganese-based Prussian blue Na was obtained by co-precipitation reaction at C. 1.76 Mn 0.51 Fe 0.41 Zn 0.08 [Fe(CN)6] 0.92 ·3.12H2O. The above Prussian blue, carbon fiber, and polytetrafluoroethylene were mixed in a weight ratio of 93:5:2. The polytetrafluoroethylene was fiberized by shear dispersion. The mixed powder was then dry-coated onto an aluminum current collector to obtain a Prussian blue layer. Morderne zeolite (CaNa2K2)[AlSi5O 12 ]·7H2O was used for sand milling to obtain D 50 The particles were 100 nm in size and then dehydrated at 400°C for 2 hours in air to obtain dehydrated mordenite zeolite. The zeolite, carbon fiber, and polytetrafluoroethylene (PTFE) were mixed in a weight ratio of 93:5:2. The PTFE was fiberized by shear dispersion, and the mixed powder was dry-coated onto a Prussian blue layer to obtain a Prussian blue composite electrode. The thickness ratio of the zeolite layer to the Prussian blue layer was measured to be 1:5. The Prussian blue composite electrode prepared in this example was tested according to the method of Example 1. At 0.1C, the capacity was 132.8 mAh / g; at 10C, the capacity retention rate was 84.9% compared to 0.1C; and at 5C, after 200 cycles, the capacity retention rate was 92.8%.

[0057] Example 3: Using sodium ferrocyanide, manganese sulfate, ferrous sulfate, nickel sulfate, and sodium citrate as precursors, at 60 °C... o Manganese-based Prussian blue Na was obtained by co-precipitation reaction at C. 1.79 Mn 0.59 Fe 0.19 Ni 0.22 [Fe(CN)6] 0.93 ·2.77H2O. The above Prussian blue, acetylene black, and polytetrafluoroethylene were mixed in a weight ratio of 96:3:1. The polytetrafluoroethylene was fiberized by shear dispersion. The mixed powder was then dry-coated onto an aluminum current collector to obtain a Prussian blue layer. The zeolite Ca[Al2Si7O]2 was then added. 18 ]·6H2O was used for sand milling to obtain D 50The particles were 100 nm in size and then dehydrated at 400°C for 2 hours in air to obtain dehydrated sheet zeolite. The zeolite, acetylene black, and polytetrafluoroethylene (PTFE) were mixed in a weight ratio of 96:3:1. The PTFE was fiberized by shear dispersion, and the mixed powder was dry-coated onto a Prussian blue layer to obtain a Prussian blue composite electrode. The thickness ratio of the zeolite layer to the Prussian blue layer was measured to be 1:20. The Prussian blue composite electrode prepared in this example was tested according to the method of Example 1. At 0.1C, the capacity was 130.2 mAh / g; at 10C, the capacity retention was 85.3% compared to 0.1C; and at 5C, after 200 cycles, the capacity retention was 94.1%.

[0058] Example 4: Using sodium ferrocyanide, manganese sulfate, copper sulfate, nickel sulfate, and sodium citrate as precursors, at 60 °C... o Manganese-based Prussian blue Na was obtained by co-precipitation reaction at C. 1.74 Mn 0.58 Ni 0.29 Cu 0.13 [Fe(CN)6] 0.94 ·2.49H2O. The above Prussian blue, carbon nanotubes, and polytetrafluoroethylene (PTFE) were mixed in a weight ratio of 94:5:1. The PTFE was fiberized by shear dispersion. The mixed powder was then dry-coated onto an aluminum current collector to obtain a Prussian blue layer. Natural clinoptilolite was sand-milled to obtain D. 50 The particles were 100 nm in size and then dehydrated at 400°C for 2 hours in air to obtain dehydrated clinoptilolite. The zeolite, carbon nanotubes, and polytetrafluoroethylene (PTFE) were mixed in a weight ratio of 94:5:1. The PTFE was fiberized by shear dispersion, and the mixed powder was dry-coated onto a Prussian blue layer to obtain a Prussian blue composite electrode. The thickness ratio of the zeolite layer to the Prussian blue layer was measured to be 1:10. The Prussian blue composite electrode prepared in this example was tested according to the method of Example 1. At 0.1C, the capacity was 126.9 mAh / g; at 10C, the capacity retention rate was 84.1% compared to 0.1C; and at 5C, after 200 cycles, the capacity retention rate was 90.1%.

[0059] Comparative Example 1:

[0060] The difference from Example 1 is that it does not involve coating with natural clinoptilolite; otherwise, it is the same as Example 1 and will not be repeated here.

[0061] The Prussian blue composite electrode prepared in this comparative example was tested according to the method in Example 1. The capacity retention rate at 10C was 70.3% compared to 0.1C. (See Figure 1 for details.) Figure 5 After 200 cycles at 5C, the capacity retention rate was 71.1%. Figure 6 As shown.

[0062] Comparative Example 2:

[0063] The difference from Example 1 is that the ratio of the thickness of the zeolite layer to the thickness of the Prussian blue layer is 1:30. The rest is the same as in Example 1, and will not be repeated here.

[0064] The Prussian blue composite electrode prepared in this comparative example was tested according to the method of Example 1. The capacity retention rate was 81.2% at 10C compared to 0.1C, and the capacity retention rate was 78.1% after 200 cycles at 5C.

[0065] Comparative Example 3:

[0066] The difference from Example 1 is that the ratio of the thickness of the zeolite layer to the thickness of the Prussian blue layer is 1:3. Everything else is the same as in Example 1 and will not be repeated here.

[0067] The Prussian blue composite electrode prepared in this comparative example was tested according to the method of Example 1. The capacity retention rate was 75.8% at 10C compared to 0.1C, and the capacity retention rate was 82.1% after 200 cycles at 5C.

[0068] Comparative Example 4:

[0069] The difference from Example 1 is that the zeolite was not dehydrated. Everything else is the same as in Example 1, and will not be repeated here.

[0070] The Prussian blue composite electrode prepared in this comparative example was tested according to the method of Example 1. The capacity retention rate was 73.6% at 10C compared to 0.1C, and the capacity retention rate was 81.4% after 200 cycles at 5C.

[0071] Comparative Example 5:

[0072] The difference from Example 1 is that the zeolite was not pulverized. Everything else is the same as in Example 1, and will not be repeated here.

[0073] The Prussian blue composite electrode prepared in this comparative example was tested according to the method of Example 1. The capacity retention rate was 78.1% at 10C compared to 0.1C, and 85.1% after 200 cycles at 5C.

[0074] Comparative Example 6:

[0075] The difference from Example 1 is that the zeolite is replaced with alumina of the same size and content. Everything else is the same as in Example 1, and will not be repeated here.

[0076] The Prussian blue composite electrode prepared in this comparative example was tested according to the method of Example 1. The capacity retention rate was 65.4% at 10C compared to 0.1C, and 73.4% at 5C after 200 cycles.

[0077] Comparative Example 7:

[0078] The difference from Example 1 is that the zeolite is replaced with silica of the same size and content. Everything else is the same as in Example 1, and will not be repeated here.

[0079] The Prussian blue composite electrode prepared in this comparative example was tested according to the method of Example 1. The capacity retention rate was 68.2% at 10C compared to 0.1C, and 74.2% at 5C after 200 cycles.

[0080] Comparative Example 8:

[0081] The difference from Example 1 is that a wet process was used to coat the Prussian blue layer and the zeolite layer. Everything else is the same as in Example 1, and will not be repeated here.

[0082] The so-called wet process refers to mixing Prussian blue or zeolite, carbon nanotubes, and polytetrafluoroethylene in an organic solvent according to the proportions in Example 1, stirring thoroughly, coating the mixture, and finally drying it under vacuum to obtain the composite electrode. The Prussian blue composite electrode prepared in this comparative example was tested according to the method of Example 1. At 10C, the capacity retention rate was 80.5% compared to 0.1C, and after 200 cycles at 5C, the capacity retention rate was 85.3%.

[0083] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a Prussian blue composite electrode, characterized in that, Includes the following steps: S1: Mix manganese-based Prussian blue, conductive agent and binder in a mass ratio of 92~96:3~7:1~5, and coat it onto the current collector using a dry coating process to obtain a Prussian blue layer. S2: Crush and dehydrate the zeolite to obtain zeolite powder; S3: Mix zeolite powder, conductive agent and binder in a mass ratio of 92~96:3~7:1~5, and coat them onto the surface of the Prussian blue layer using a dry coating process to form a zeolite layer that completely covers the Prussian blue layer, thereby obtaining the Prussian blue composite electrode. In step S2, the zeolite is first pulverized to 50-200 nanometers using a sand milling method, and then the pulverized zeolite is dehydrated. The dehydration temperature is 300℃-500℃, the dehydration time is 1-5 hours, and the dehydration atmosphere is air or oxygen. After dehydration, the transport rate of sodium ions can be improved, and the crystal water released during the charging and discharging of Prussian blue can be absorbed, thereby improving the rate performance and cycle performance.

2. The method for preparing a Prussian blue composite electrode according to claim 1, characterized in that, The ratio of the thickness of the zeolite layer to the thickness of the Prussian blue layer is 1:5 to 20.

3. The method for preparing a Prussian blue composite electrode according to claim 1, characterized in that, The manganese-based Prussian blue formula is Na. d Mn 1-t M t [Fe(CN)6] h ·zH2O, where M is selected from at least one of Fe, Co, Ni, Cu, Zn, and Cr, 1.7≤d≤2, 0.4≤t≤0.6, 0.9≤h≤1, and 2≤z≤4.

4. The method for preparing a Prussian blue composite electrode according to claim 1, characterized in that, The zeolite has the general formula A. (x / q) [(AlO2) x (SiO2) y ]·nH2O, where A is at least one of Ca, Na, K, Ba, and Sr, where 2≤y / x≤5, and q is the charge number of A.

5. The method for preparing a Prussian blue composite electrode according to claim 1, characterized in that, In steps S1 and S3, the conductive agent is acetylene black, carbon nanotubes, carbon fibers, or graphene, and the binder is polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, or perfluoroethylene propylene.

6. A Prussian blue composite electrode, based on the preparation method of the Prussian blue composite electrode according to any one of claims 1-5, characterized in that, include: The Prussian blue layer and the zeolite layer covering the surface of the Prussian blue layer.

7. The application of the Prussian blue composite electrode according to claim 6 in a sodium-ion battery.

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