A post-processing method of prussian blue type positive electrode material and application thereof

Abstract

The application discloses a kind of post-processing methods of prussian blue positive material and application, it is related to battery material technical field.The post-processing method of the application mixes water-resistant dispersant solution with mass concentration of 0.1%-5% with prussian blue matrix containing water, and the prussian blue dispersion slurry with solid content of 10%-50% is prepared;The prussian blue positive material is prepared after the slurry is filtered and dried.The post-processing method is less changed to the existing process route, and the input cost is low;It utilizes water-resistant dispersant to modify the surface of prussian blue, significantly reduces the resorption rate and resorption amount of prussian blue to moisture in high dew point environment, while the electrical performance is not affected;The prussian blue positive material prepared has good dispersibility, tap density is improved, which is beneficial to subsequent uniform slurry and prepared high compaction electrode, wide applicability, can be used for preparing positive electrode, secondary battery and electric device.

Description

Technical Field

[0001] This invention relates to the field of battery materials technology, and more specifically, to a post-processing method and application of Prussian blue cathode materials. Background Technology

[0002] Prussian blue cathode materials (PBLs) possess advantages such as high capacity, low cost, and good conductivity, making them promising candidates for electrochemical energy storage. However, after deep dehydration, PBLs are prone to reabsorbing moisture when exposed to high dew point environments. This reabsorbed moisture affects the structure and surface properties of the PBLs, altering their water characteristics. This can lead to gas generation in the resulting battery cells, deteriorating cycle performance and posing safety risks. Furthermore, the hygroscopic nature of PBLs results in poor dispersibility and reduced tapping, worsening the material's processing performance. Therefore, suppressing the reabsorption of moisture by PBLs under high dew point environments is crucial.

[0003] How to significantly reduce the reabsorption rate and amount of moisture in the prepared Plutonium under high dew point conditions, while maintaining its electrical properties as good as before treatment, is a technical problem that urgently needs to be solved in this field.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a post-processing method and application for Prussian blue cathode materials to solve the above-mentioned technical problems.

[0006] This invention is implemented as follows:

[0007] In a first aspect, embodiments of the present invention provide a post-processing method for Prussian blue-type cathode materials, comprising the following steps:

[0008] The water-resistant dispersant is dissolved to prepare a water-resistant dispersant solution with a mass concentration of 0.1%-5%;

[0009] A Prussian blue dispersion slurry was prepared by mixing an aqueous Prussian blue matrix with a water-resistant dispersant solution.

[0010] Prussian blue-based cathode materials are prepared by filtering and drying the Prussian blue dispersion slurry.

[0011] Secondly, embodiments of the present invention provide a positive electrode sheet comprising the Prussian blue-type positive electrode material as described above.

[0012] Thirdly, embodiments of the present invention provide a secondary battery comprising a positive electrode as described above.

[0013] Fourthly, embodiments of the present invention provide an electrical device comprising a secondary battery as described above.

[0014] The present invention has the following beneficial effects:

[0015] This invention provides a post-processing method and application for Prussian blue-based cathode materials. The method involves uniformly mixing an aqueous Prussian blue matrix with a water-resistant dispersant solution, followed by filtration and drying to modify the surface of the Prussian blue matrix. The modified Prussian blue exhibits significantly reduced reabsorption rate and amount of moisture under high dew point conditions, while its electrical properties remain comparable to those before treatment. The treated Prussian blue powder also demonstrates good dispersibility and increased tap density, which is beneficial for homogenization and the production of high-pressure cathode sheets. Furthermore, the drying rate of the water-resistant dispersant-modified Prussian blue after filtration is improved, helping to reduce energy consumption during the drying process. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0017] Currently, methods to suppress the reabsorption of moisture by p-blue in high dew point environments include solvent treatment, compound coating, and special synthesis methods. Solvent treatment involves mixing p-blue with a solvent and then drying it, utilizing the passivation effect of the organic solvent on the surface to suppress reabsorption; some of the solvent can also be recovered. Compound coating methods involve coating the p-blue surface with oxides such as silicon, titanium, or zirconium, inhibiting reabsorption by isolating the p-blue matrix from external contact. Special synthesis methods, such as microemulsion synthesis of p-blue, coat the surface of the p-blue material with a layer of organic molecules, achieving a similar effect to solvent treatment methods, also suppressing reabsorption through surface passivation.

[0018] Invention patent CN116864656A proposes a two-step coating method to suppress p-lan reabsorption. The method involves treating the p-lan matrix successively with a tannic acid precursor solution and an octadecylamine precursor solution, and then placing the treated p-lan in a vacuum dryer at 80°C. The resulting p-lan has improved storage performance under high dew point conditions.

[0019] Invention patent CN116425176A proposes a post-treatment method for p-blue to suppress its reabsorption. This method involves dispersing aqueous p-blue in a high-boiling-point anhydrous organic solvent to form a mixed slurry. Through two-stage evaporation, the water content of the p-blue is first evaporated, followed by the evaporation of the high-boiling-point organic solvent. The organic solvent used in this method passivates the surface of the p-blue, making it less prone to reabsorption of water. Simultaneously, the two-stage evaporation also allows for the recovery of the organic solvent.

[0020] Invention patent CN115411260B proposes a method for gas-phase modification of plutonium to suppress plutonium reabsorption. This method employs a water-soluble liquid coating agent containing silicon, titanium, or zirconium. During the plutonium drying process, vaporization is introduced, and the crystal water released during heating and holding reacts with the coating agent in the silicon, titanium, or zirconium-containing gas mixture to form a uniform oxide layer coating the surface of the plutonium particles. The presence of this oxide coating layer isolates the modified plutonium particles from direct contact with air, preventing reabsorption of water and improving the material's storage stability. Furthermore, the coating layer prevents direct contact between the material and the electrolyte, reducing interfacial side reactions and improving the material's reaction stability.

[0021] Invention patent CN116964000A discloses a method for preparing anti-reabsorption p-blue using a water-in-oil microemulsion. The method involves mixing a sodium ferrocyanide solution with a hydrophobic liquid and a surfactant to obtain a precursor microemulsion. A transition metal salt is then added to the microemulsion for reaction. The resulting p-blue microemulsion is aged, separated, washed, and dried to obtain p-blue coated with an oil film. This oil film prevents p-blue from absorbing water during storage.

[0022] The above-mentioned solvent treatment methods suffer from high costs due to the use of organic solvents, and the high energy consumption in the recovery and reuse processes, making industrialization difficult and limiting their widespread application. Compound coating processes are complex and technically challenging, increasing production time and costs. Suppressing Prussian blue's reabsorption of moisture in high dew point environments requires significant modifications and incurs high investment costs, limiting its widespread adoption and mass production. This invention proposes a post-processing method and application for Prussian blue-based cathode materials to solve the above-mentioned technical problems, as detailed below:

[0023] In a first aspect, embodiments of the present invention provide a post-processing method for Prussian blue-type cathode materials, comprising the following steps:

[0024] The water-resistant dispersant is dissolved to prepare a water-resistant dispersant solution with a mass concentration of 0.1%-5%;

[0025] A Prussian blue dispersion slurry was prepared by mixing an aqueous Prussian blue matrix with a water-resistant dispersant solution.

[0026] Prussian blue-based cathode materials are prepared by filtering and drying the Prussian blue dispersion slurry.

[0027] In an optional embodiment of the present invention, the water-resistant dispersant is selected from at least one of polyacrylic acid type dispersants, polyacrylate type dispersants, and polyacrylic acid derivative type dispersants; wherein, polyacrylate is selected from at least one of potassium polyacrylate, amine polyacrylate, and sodium polyacrylate, and polyacrylic acid derivative is selected from at least one of polyacrylates, polyacrylonitrile, and polyacrylamide.

[0028] It should be noted that polyacrylate-based dispersants ionize in water to form high-molecular-weight anions and many small-molecular-weight ions (such as sodium ions, potassium ions, and ammonium ions). These high-molecular-weight anions adsorb onto the surface of the dispersed particles, forming a stable diffusion layer of charged ions, i.e., an electrical double layer. Because ions with the same charge repel each other, electrostatic repulsion is formed, which effectively prevents particle flocculation in the aqueous medium, thereby achieving the purpose of dispersion. Polyacrylic acid derivative dispersants, after dissolving, can adsorb onto the surface of the dispersed particles, forming a macromolecular film when the dispersion slurry dries, giving the material excellent water resistance.

[0029] It should be noted that water-resistant dispersants can effectively improve the dispersibility of Prussian blue matrix in liquids, inhibit its aggregation, and improve the viscosity stability of the slurry, thereby forming a stable suspension or emulsion and preventing the Prussian blue matrix from settling or agglomerating, thus improving the uniformity and stability of the material. Furthermore, the addition of water-resistant dispersants can reduce interfacial tension and increase the solubility of active substances, thereby improving the utilization rate of Prussian blue.

[0030] It should be noted that the solvents used to dissolve water-resistant dispersants may vary. The appropriate solvent system should be selected based on the specific type of water-resistant dispersant, and is not limited to solvents such as water and alcohols.

[0031] In an optional embodiment of the present invention, the mass concentration of the water-resistant dispersant solution is 0.5%-2%. Specifically, the mass concentration is reasonably adjusted according to the type and amount of raw materials actually used, and is selected from any one of 0.5%, 0.6%, 0.7%, 1%, 1.5%, and 1.8%, or other values ​​within the range of 0.5%-2%.

[0032] It should be noted that if the concentration of the water-resistant dispersant is too high, it will increase the viscosity of the slurry, causing the originally dispersed particles to re-agglomerate and form flocculation, thus increasing the viscosity of the slurry, reducing its fluidity, and consequently affecting the overall performance of the battery. If the concentration of the water-resistant dispersant is too low, it will cause the dispersant to migrate and redistribute on the Pluton matrix during drying, weakening its improving effect.

[0033] In an optional embodiment of the present invention, the preparation process of Prussian blue dispersion slurry further includes heating and stirring the mixed solution, wherein the heating temperature is 10℃-90℃, preferably 20℃-60℃.

[0034] It should be noted that appropriate heating can help promote the dissolution of water-resistant dispersants and the rapid dispersion of Prussian blue matrix particles. The temperature should be adjusted reasonably according to the actual amount of material being processed.

[0035] In an optional embodiment of the present invention, the obtained Prussian blue dispersion slurry is filtered. The filtration method is selected reasonably according to actual needs, such as reduced pressure filtration, vacuum filtration, etc.

[0036] In optional embodiments of the present invention, the drying method is selected from any one of blower drying, vacuum drying, and drying under a specific atmosphere; wherein, the specific atmosphere refers to an inert atmosphere and / or a reducing atmosphere.

[0037] Blower air drying typically employs a continuous drying method, which uses heated air as the heating source. Through forced ventilation and heating, the moisture on the surface of the material is evaporated, thus achieving the purpose of drying.

[0038] Vacuum drying typically employs intermittent drying, utilizing an environment where the vacuum level is lower than atmospheric pressure to allow moisture to evaporate at low temperatures, thus achieving the purpose of drying.

[0039] Inert and / or reducing atmospheres are protective atmospheres that can effectively inhibit oxidation and structural damage of Prussian blue during the drying process.

[0040] In an optional embodiment of the present invention, the drying temperature is 80℃-250℃ and the drying time is 1h-32h.

[0041] It should be noted that while high temperatures can accelerate the evaporation of moisture, excessively high temperatures can cause the surface of the material to harden too quickly, hindering the diffusion of internal moisture and thus reducing drying efficiency. Maintaining a high-temperature environment requires more energy consumption, which not only increases production costs but may also have a negative impact on the environment. In addition, excessively high drying temperatures may cause the product to scorch or deteriorate, such as through oxidation or browning.

[0042] If the drying temperature is too low, the drying time will be prolonged, increasing energy consumption and production costs. Furthermore, excessively low temperatures may result in poor product morphology, such as uneven particle size or agglomeration, which affects the product's appearance and quality, reducing its market competitiveness. In addition, materials dried at low temperatures tend to have a higher moisture content, increasing the risk of gas generation in the product.

[0043] In other optional embodiments of the present invention, the drying temperature and time can be reasonably set according to the actual amount of raw materials being processed.

[0044] In an optional embodiment of the present invention, the Prussian blue matrix (also referred to as Prussian blue matrix) is a washing material used in the synthesis of Prussian blue material, and its composition is selected from pure iron-type Prussian blue (Na2Fe[Fe(CN)6]) and iron-manganese mixed-type Prussian blue (Na2Fe... x Mn 1-xThe Prussian blue is either [Fe(CN)6] or pure manganese Prussian blue (Na2Mn[Fe(CN)6]), the Prussian blue matrix has a water content of 10%-30%, and the Prussian blue cathode material is Prussian blue powder modified by the post-processing method of this invention.

[0045] In an optional embodiment of the present invention, the Prussian blue cathode material has a reabsorption rate of less than 1000 ppm / h at a dew point of -30°C, a 24-hour reabsorption amount of less than 10000 ppm, an electrical performance deviation of ≤1.5% from that before treatment, and a tap density of 0.7 g / cc-1.2 g / cc.

[0046] The tap density directly affects the volumetric energy density and electrochemical performance of a material. Tap density refers to the mass per unit volume of powder after it has been vibrated and compacted under specified conditions. It is an important indicator for evaluating active materials, especially in sodium-ion batteries, where a high tap density means a large mass of active material per unit volume, resulting in a high volumetric capacity.

[0047] Electrical performance specifically refers to capacity performance, rate performance, and cycle performance.

[0048] The reabsorption rate and amount of moisture by Pluronic acid in high dew point environments affect its water properties, surface structure, and phase structure. High moisture reabsorption makes the resulting battery cells prone to gas generation, deteriorating cycle performance and posing safety risks. Simultaneously, Pluronic acid's hygroscopic properties lead to poor dispersibility and reduced tapping, worsening the electrode processing performance and thus altering the material's conductivity and stability. A rapid moisture reabsorption rate results in a narrow processing time window.

[0049] This invention utilizes a water-resistant dispersant to modify the surface of Prussian blue, significantly reducing the reabsorption rate and amount of moisture by Prussian blue in high dew point environments, while the electrical properties remain unaffected. The resulting Prussian blue-based cathode material exhibits good dispersibility and improved tap density, which is beneficial for subsequent homogenization and the production of high-voltage solid electrode sheets, making it widely applicable.

[0050] Secondly, embodiments of the present invention provide a positive electrode sheet comprising the Prussian blue-type positive electrode material as described above.

[0051] Thirdly, embodiments of the present invention provide a secondary battery comprising a positive electrode as described above.

[0052] Fourthly, embodiments of the present invention provide an electrical device comprising a secondary battery as described above.

[0053] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0054] Example 1

[0055] This embodiment provides a post-processing method for Prussian blue-based cathode materials, which includes the following steps:

[0056] S1: Dissolve the water-resistant dispersant ammonium polyacrylate in water to prepare a water-resistant dispersant solution with a mass concentration of 0.5%.

[0057] S2: A water-containing Prussian blue matrix with the composition Na2Fe 0.5 Mn 0.5 [Fe(CN)6] was added to the water-resistant dispersant solution prepared by S1 and mixed to obtain a Prussian blue dispersion slurry with a solid content of 30%.

[0058] It should be noted that the mixing process involves stirring and heating simultaneously at a temperature of 50°C.

[0059] S3: Filter the Prussian blue dispersion slurry prepared in S2 to obtain a filter cake.

[0060] S4: The filter cake is dried in a vacuum oven to obtain Prussian blue cathode material, wherein the drying temperature is 180℃ and the time is 5h.

[0061] Example 2

[0062] This embodiment provides a post-processing method for Prussian blue-type cathode materials, which differs from Embodiment 1 only in that:

[0063] S1: The water-resistant dispersant is polyacrylic acid.

[0064] Example 3

[0065] This embodiment provides a post-processing method for Prussian blue-type cathode materials, which differs from Embodiment 1 only in that:

[0066] S1: The water-resistant dispersant is polyacrylate, and the solvent is ethyl acetate.

[0067] Example 4

[0068] This embodiment provides a post-processing method for Prussian blue-type cathode materials, which differs from Embodiment 1 only in that:

[0069] S1: The mass concentration of the water-resistant dispersant solution is 0.1%.

[0070] Example 5

[0071] This embodiment provides a post-processing method for Prussian blue-type cathode materials, which differs from Embodiment 1 only in that:

[0072] S1: The mass concentration of the water-resistant dispersant solution is 5%.

[0073] Example 6

[0074] This embodiment provides a post-processing method for Prussian blue-type cathode materials, which differs from Embodiment 1 only in that:

[0075] S2: The heating temperature is 20℃.

[0076] Example 7

[0077] This embodiment provides a post-processing method for Prussian blue-type cathode materials, which differs from Embodiment 1 only in that:

[0078] S2: The aqueous Prussian blue matrix is ​​composed of Na2Fe[Fe(CN)6].

[0079] Comparative Example 1

[0080] This comparative example provides a Prussian blue-based cathode material. The raw material is raw washing material. The Prussian blue-based cathode material is obtained by directly drying the aqueous Prussian blue matrix without performing the post-processing operation in Example 1. The details are as follows:

[0081] Take a water-containing Prussian blue matrix with the composition Na2Fe 0.5 Mn 0.5 [Fe(CN)6] was dried in a vacuum oven to obtain Prussian blue cathode material, wherein the drying temperature was 180℃ and the drying time was 5h.

[0082] Comparative Example 2

[0083] This comparative example provides a Prussian blue-based cathode material, aiming to obtain a Prussian blue-based cathode material with lower water content, without performing the post-processing operations described in Example 1. Its only difference from Comparative Example 1 is:

[0084] The drying temperature is 200℃ and the time is 5 hours.

[0085] Comparative Example 3

[0086] This comparative example provides a post-processing method for Prussian blue-based cathode materials, aiming to obtain Prussian blue-based cathode materials with improved dispersion. Its difference from Example 1 lies only in:

[0087] S1: Ethanol is used as the dispersant solution.

[0088] Experimental Example 1

[0089] This experiment investigated the reabsorption of Prussian blue-based cathode materials prepared in Examples 1-7 and Comparative Examples 1-3. A Karl Fischer moisture analyzer was used for the testing, and the method was as follows: After drying, the material was taken at a dew point of -30°C, and the moisture content at 0 hours was measured using a Karl Fischer moisture analyzer. The dried material was then exposed to an environment with a dew point of -30°C, and the moisture content was measured at 4 hours and 24 hours of exposure. The hourly reabsorption rate was calculated using the 4-hour reabsorption rate. The relevant results are shown in Table 1.

[0090] Table 1. Reabsorption data at a dew point of -30℃.

[0091]

[0092]

[0093] Table 1 shows that the Prussian blue cathode material modified by the post-processing method of this invention exhibits a significant reduction in both the reabsorption rate and amount of moisture in an environment with a dew point of -30°C. Specifically, Comparative Example 1 showed a reabsorption amount 6.75 times that of Example 1 after 4 hours and 4.70 times after 24 hours. Furthermore, the data from Comparative Examples 1 and 2 indicate that the higher the drying temperature within a reasonable range, the greater the reabsorption amount and the faster the reabsorption rate within the same timeframe.

[0094] Experimental Example 2

[0095] This experiment tested the electrical properties of the Prussian blue cathode materials prepared in Examples 1-7 and Comparative Examples 1-3. The test method is as follows: The discharge capacity, rate and cycle are evaluated using a button cell with sodium sheet as negative electrode. Specifically: (1) Prussian blue positive electrode material, conductive carbon black and binder PVDF are weighed in a mass ratio of 7:2:1, and NMP solvent is added and mixed evenly to obtain positive electrode slurry. The positive electrode slurry is coated on aluminum foil and dried to obtain positive electrode sheet; (2) The battery is packed in a 2032 battery case, with sodium sheet as negative electrode and fiber separator (model Whatman Grade GF / D) used. The electrolyte is 1mol / L NaPF6 (EC:PC=1:1, 5% FEC); (3) The battery is left to stand for 12 hours. The rated capacity is set to 150mA / g to determine the current density. The capacity is tested by setting a 0.1C charge and discharge program, the rate is tested by setting a 10C charge and discharge program, and the cycle is tested by setting a 2C charge and discharge program. The voltage range is 2.0V-4.0V.

[0096] The 0.1C capacity deviation of Examples 1-7 and Comparative Example 1 was used as the electrical performance deviation, and the relevant results are shown in Table 2.

[0097] Table 2 Electrical performance test results

[0098]

[0099] The data in Table 2 show that the capacity deviation of Examples 1-7 and Comparative Examples 1-3 is ≤1.5%. The binding rate and cycling data indicate that the electrical performance of the Prussian blue cathode material modified by the post-processing method of this invention is unaffected. It should be noted that the electrical performance test results in Example 7 are all higher than those in Examples 1-6, mainly due to the change in material composition.

[0100] Experimental Example 3

[0101] This experiment tested the tap density of the Prussian blue cathode materials prepared in Examples 1-7 and Comparative Examples 1-3. The testing instrument was a tap density meter, and the testing method is detailed in GB / T 5162-2021, "Determination of Tap Density of Metal Powders". The relevant results are shown in Table 3.

[0102] Table 3 Tap density data

[0103] sample Tap density (g / cc) Example 1 0.81 Example 2 0.76 Example 3 0.83 Example 4 0.74 Example 5 0.70 Example 6 0.69 Example 7 0.67 Comparative Example 1 0.60 Comparative Example 2 0.58 Comparative Example 3 0.65

[0104] The data in Table 3 show that the tap density of the Prussian blue cathode material modified by the post-processing method of this invention is improved. The tap density of Comparative Example 3 is also higher than that of Comparative Example 1. This is because ethanol has a lower surface tension, which allows it to displace moisture from the surface of the Prussian blue matrix particles, thereby reducing capillary forces, decreasing the aggregation of the Prussian blue matrix, and improving tap density. However, compared to Comparative Example 1, the reabsorption of moisture in Comparative Example 3 was not improved.

[0105] In summary, the post-processing method for Prussian blue cathode materials provided in this embodiment of the invention has the following characteristics:

[0106] (1) By modifying the surface of PBL with a water-resistant dispersant, the reabsorption rate and amount of water of PBL under high dew point environment were significantly reduced, while the electrical properties were not affected.

[0107] (2) Prussian blue cathode materials have good dispersibility and improved tap density, which is beneficial for subsequent homogenization and the preparation of high-pressure solid electrode sheets.

[0108] (3) The post-processing method requires less modification to the existing process route and has low input cost;

[0109] Furthermore, the Prussian blue cathode material prepared by the post-processing method of this invention has wide applicability and can be used to prepare cathode sheets, secondary batteries and electrical devices.

[0110] The above are merely preferred embodiments of the present invention and are not intended to limit the present 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 post-processing method for Prussian blue-based cathode materials, characterized in that, The post-processing method includes the following steps: The water-resistant dispersant is dissolved to prepare a water-resistant dispersant solution with a mass concentration of 0.1%-5%; A water-containing Prussian blue matrix is ​​mixed with the water-resistant dispersant solution to prepare a Prussian blue dispersion slurry with a solid content of 10%-50%. The Prussian blue dispersion slurry was filtered and dried to obtain a Prussian blue-based cathode material.

2. The post-processing method according to claim 1, characterized in that, The Prussian blue matrix is ​​selected from any one of pure iron-type Prussian blue, iron-manganese mixed-type Prussian blue, and pure manganese-type Prussian blue; preferably, iron-manganese mixed-type Prussian blue. Preferably, the water-resistant dispersant is selected from at least one of polyacrylic acid type dispersants, polyacrylate type dispersants, and polyacrylic acid derivative type dispersants; wherein the polyacrylate type dispersant is selected from at least one of potassium polyacrylate, polyacrylamide, and sodium polyacrylate, and the polyacrylic acid derivative is selected from at least one of polyacrylates, polyacrylonitrile, and polyacrylamide.

3. The post-processing method according to claim 1, characterized in that, The mass concentration of the water-resistant dispersant solution is 0.5%-2%.

4. The post-processing method according to claim 1, characterized in that, The preparation of the Prussian blue dispersion slurry also includes heating and stirring the mixed solution, wherein the heating temperature is 10℃-90℃, preferably 20℃-60℃.

5. The post-processing method according to claim 1, characterized in that, The drying method is selected from any one of blower drying, vacuum drying, and drying under a specific atmosphere; wherein, the specific atmosphere refers to an inert atmosphere and / or a reducing atmosphere.

6. The post-processing method according to claim 1, characterized in that, The drying temperature is 80℃-250℃, and the time is 1h-32h.

7. The post-processing method according to claim 1, characterized in that, The Prussian blue-based cathode material exhibits a reabsorption rate of less than 1000 ppm / h at a dew point of -30℃, a 24-hour reabsorption amount of less than 10000 ppm, an electrical performance deviation of ≤1.5% from that before treatment, and a tap density of 0.7 g / cc - 1.2 g / cc.

8. A positive electrode sheet, characterized in that, It includes the Prussian blue-type cathode material as described in any one of claims 1-7.

9. A secondary battery, characterized in that, It includes the positive electrode as described in claim 8.

10. An electrical device, characterized in that, It includes the secondary battery as described in claim 9.

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