A preparation method for improving the cycle performance of a manganese-based prussian white material

Abstract

The application discloses a preparation method for improving the cycle performance of a manganese-based Prussian white material, and relates to the technical field of batteries.The method comprises the following steps: step 1: dissolving manganese chloride tetrahydrate, cesium chloride and sodium tungstate dihydrate in deionized water, then adding sodium citrate, stirring, and adding a sodium hydroxide solution dropwise to obtain a manganese salt mixed solution; step 2: adding sodium ferrocyanide decahydrate to deionized water, stirring, and obtaining a sodium ferrocyanide solution; step 3: adding the sodium ferrocyanide solution to the manganese salt mixed solution dropwise, stirring, and obtaining a suspension; and step 4: performing a hydrothermal synthesis reaction on the suspension, and obtaining the manganese-based Prussian white material through centrifugation and drying after cooling.The manganese-based Prussian white material prepared by the method can be applied to sodium batteries, can effectively relieve internal stress in the cycle process, can improve the electron transfer rate, can maintain the structural stability in the cycle process, and can effectively improve the cycle performance of the battery.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically a method for preparing manganese-based Prussian white materials with improved cycle performance. Background Technology

[0002] In recent years, driven by the global electrification trend, various industries have become heavily reliant on lithium batteries. However, lithium is a scarce mineral with low global reserves and uneven distribution, making its price prone to drastic fluctuations. Therefore, sodium batteries are considered an important supplement to lithium batteries and an alternative in some application scenarios. Sodium-ion batteries, in particular, do not rely on lithium ore resources, their raw material sourcing is not limited by region or production capacity, and their manufacturing process is highly compatible with existing lithium battery production lines, enabling rapid mass production. Furthermore, the cathode material in sodium batteries directly determines the battery's cycle stability; therefore, optimizing the structure of cathode materials has become a key research focus in the industry.

[0003] Manganese-based Prussian white, as a cathode material for sodium-ion batteries, possesses advantages such as a three-dimensional open lattice structure, high theoretical specific capacity, and low preparation cost. However, pure-phase materials suffer from defects such as Mn dissolution and loss, structural collapse, and low electronic conductivity, resulting in poor cycle performance and failing to meet practical application requirements. Therefore, there is an urgent need for a simple, scalable preparation method that can significantly improve the material's cycle performance.

[0004] In summary, providing a preparation method to improve the cycling performance of manganese-based Prussian white materials is of great significance in order to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing manganese-based Prussian white materials with improved cycle performance, so as to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A method for preparing manganese-based Prussian white materials with improved cycling performance includes the following steps: Step 1: Dissolve cesium chloride, manganese chloride tetrahydrate, and sodium tungstate dihydrate in deionized water, then add sodium citrate, stir, and add sodium hydroxide solution dropwise to obtain a mixed manganese salt solution; Step 2: Add sodium ferrocyanide decahydrate to deionized water and stir to obtain a sodium ferrocyanide solution; Step 3: Add sodium ferrocyanide solution dropwise to the manganese salt mixture and stir to obtain a suspension; Step 4: The suspension is subjected to a hydrothermal synthesis reaction, cooled, centrifuged, and dried to obtain manganese-based Prussian white material; In step 1, the molar ratio of cesium chloride to manganese chloride tetrahydrate is 1:(30~55), and the molar ratio of sodium tungstate dihydrate to manganese chloride tetrahydrate is 1:(50~75).

[0007] Further, in step 1, the molar ratio of cesium chloride to manganese chloride tetrahydrate is 1:(40~45), and the molar ratio of sodium tungstate dihydrate to manganese chloride tetrahydrate is 1:(65~70).

[0008] Furthermore, the molar ratio of sodium ferrocyanide decahydrate to manganese chloride tetrahydrate is (0.8~1.2):(1.8~2.2).

[0009] Furthermore, the hydrothermal synthesis reaction is carried out at a temperature of 150-170°C for 12-16 hours.

[0010] Furthermore, the sodium hydroxide solution is used to adjust the pH of the manganese salt mixture to 7-8.

[0011] A method for preparing manganese-based Prussian white materials with improved cycle performance.

[0012] Compared with the prior art, the beneficial effects achieved by the present invention are: This application uses a hydrothermal synthesis method to prepare Cs. + W 6+ Co-doped Mn-based Prussian white sodium cathode material, i.e., modified Mn-PW. Cs + Prioritize occupying Na + Lattice sites, on the one hand, large radius Cs + Effectively expanding the overall crystal lattice framework not only effectively buffers Na + The cell volume deformation during the insertion / extraction process alleviates lattice stress, preventing microcracks from forming during cycling and further causing structural collapse; simultaneously, it can broaden the Na... + Migration channel aperture, reducing Na + The diffusion barrier enhances electrochemical performance; on the other hand, the +1 valence Cs + Doping introduces additional positive charge, causing some Mn to... 3+ Restored to Mn 2+ Effectively reduces Mn in the crystal lattice 3+ The ratio reduces Mn at the source. 3+ Disproportionation and dissolution; simultaneously, some Cs + The electrolyte accumulates on the material surface, forming a more stable CEI film that prevents direct contact between the electrolyte and the active lattice, further suppressing electrolyte side reactions and Mn dissolution. Meanwhile, a small amount of W... 6+ The introduction of Mn can replace some of the active Mn sites in the lattice, inducing more Mn to maintain the overall electroneutrality of the system. 3+ Restored to Mn 2+ This suppresses the Jahn-Teller distortion at its source; furthermore, W 6+Doping can tune the electronic structure of the crystal lattice, creating localized electronic conduction pathways within it, reducing resistance, and increasing the electron transfer rate. Therefore, through Cs... + and W 6+ The dual doping can improve the defects of traditional Mn-PW in terms of structural stability, interface optimization and transport synergy, thereby enhancing the cycling performance of the material. Detailed Implementation

[0013] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] It should be noted that the following quantities are by weight. There are no special restrictions on the manufacturers of the raw materials involved in this invention. Exemplary examples include: all raw materials in the following embodiments are commercially available.

[0015] Example 1: A method for preparing manganese-based Prussian white materials with improved cycling performance, specifically including the following steps: Step 1: Dissolve cesium chloride, manganese chloride tetrahydrate, and sodium tungstate dihydrate in 100 parts of deionized water, then add sodium citrate, stir, and add sodium hydroxide solution dropwise to adjust the pH to 7.5 to obtain a manganese salt mixed solution; Step 2: Add sodium ferrocyanide decahydrate to 100 parts of deionized water and stir to obtain a sodium ferrocyanide solution; Step 3: Add sodium ferrocyanide solution dropwise to the manganese salt mixture and stir to obtain a suspension; Step 4: Transfer the suspension to a high-pressure reactor, seal it, and place it in a drying oven. Perform a hydrothermal synthesis reaction at 160°C for 14 hours. After the reaction is complete, allow it to cool naturally, centrifuge it, and then dry it at 60°C for 12 hours to obtain manganese-based Prussian white material.

[0016] In this embodiment 1, the molar ratio of cesium chloride to manganese chloride tetrahydrate is 1:43, the molar ratio of sodium tungstate dihydrate to manganese chloride tetrahydrate is 1:63, and the molar ratio of sodium ferrocyanide decahydrate to manganese chloride tetrahydrate is 1:2.

[0017] Example 2: A method for preparing manganese-based Prussian white materials with improved cycling performance, specifically including the following steps: Step 1: Dissolve cesium chloride, manganese chloride tetrahydrate, and sodium tungstate dihydrate in 100 parts of deionized water, then add sodium citrate, stir, and add sodium hydroxide solution dropwise to adjust the pH to 7.5 to obtain a manganese salt mixed solution; Step 2: Add sodium ferrocyanide decahydrate to 100 parts of deionized water and stir to obtain a sodium ferrocyanide solution; Step 3: Add sodium ferrocyanide solution dropwise to the manganese salt mixture and stir to obtain a suspension; Step 4: Transfer the suspension to a high-pressure reactor, seal it, and place it in a drying oven. Perform a hydrothermal synthesis reaction at 160°C for 14 hours. After the reaction is complete, allow it to cool naturally, centrifuge it, and then dry it at 60°C for 12 hours to obtain manganese-based Prussian white material.

[0018] In this embodiment 2, the molar ratio of cesium chloride to manganese chloride tetrahydrate is 1:33, the molar ratio of sodium tungstate dihydrate to manganese chloride tetrahydrate is 1:63, and the molar ratio of sodium ferrocyanide decahydrate to manganese chloride tetrahydrate is 1:2.

[0019] Example 3: A method for preparing manganese-based Prussian white materials with improved cycling performance, specifically including the following steps: Step 1: Dissolve cesium chloride, manganese chloride tetrahydrate, and sodium tungstate dihydrate in 100 parts of deionized water, then add sodium citrate, stir, and add sodium hydroxide solution dropwise to adjust the pH to 7.5 to obtain a manganese salt mixed solution; Step 2: Add sodium ferrocyanide decahydrate to 100 parts of deionized water and stir to obtain a sodium ferrocyanide solution; Step 3: Add sodium ferrocyanide solution dropwise to the manganese salt mixture and stir to obtain a suspension; Step 4: Transfer the suspension to a high-pressure reactor, seal it, and place it in a drying oven. Perform a hydrothermal synthesis reaction at 160°C for 14 hours. After the reaction is complete, allow it to cool naturally, centrifuge it, and then dry it at 60°C for 12 hours to obtain manganese-based Prussian white material.

[0020] In this embodiment 3, the molar ratio of cesium chloride to manganese chloride tetrahydrate is 1:38, the molar ratio of sodium tungstate dihydrate to manganese chloride tetrahydrate is 1:63, and the molar ratio of sodium ferrocyanide decahydrate to manganese chloride tetrahydrate is 1:2.

[0021] Example 4: A method for preparing manganese-based Prussian white materials with improved cycling performance, specifically including the following steps: Step 1: Dissolve cesium chloride, manganese chloride tetrahydrate, and sodium tungstate dihydrate in 100 parts of deionized water, then add sodium citrate, stir, and add sodium hydroxide solution dropwise to adjust the pH to 7.5 to obtain a manganese salt mixed solution; Step 2: Add sodium ferrocyanide decahydrate to 100 parts of deionized water and stir to obtain a sodium ferrocyanide solution; Step 3: Add sodium ferrocyanide solution dropwise to the manganese salt mixture and stir to obtain a suspension; Step 4: Transfer the suspension to a high-pressure reactor, seal it, and place it in a drying oven. Perform a hydrothermal synthesis reaction at 160°C for 14 hours. After the reaction is complete, allow it to cool naturally, centrifuge it, and then dry it at 60°C for 12 hours to obtain manganese-based Prussian white material.

[0022] In this embodiment 4, the molar ratio of cesium chloride to manganese chloride tetrahydrate is 1:48, the molar ratio of sodium tungstate dihydrate to manganese chloride tetrahydrate is 1:63, and the molar ratio of sodium ferrocyanide decahydrate to manganese chloride tetrahydrate is 1:2.

[0023] Example 5: A method for preparing manganese-based Prussian white materials with improved cycling performance, specifically including the following steps: Step 1: Dissolve cesium chloride, manganese chloride tetrahydrate, and sodium tungstate dihydrate in 100 parts of deionized water, then add sodium citrate, stir, and add sodium hydroxide solution dropwise to adjust the pH to 7.5 to obtain a manganese salt mixed solution; Step 2: Add sodium ferrocyanide decahydrate to 100 parts of deionized water and stir to obtain a sodium ferrocyanide solution; Step 3: Add sodium ferrocyanide solution dropwise to the manganese salt mixture and stir to obtain a suspension; Step 4: Transfer the suspension to a high-pressure reactor, seal it, and place it in a drying oven. Perform a hydrothermal synthesis reaction at 160°C for 14 hours. After the reaction is complete, allow it to cool naturally, centrifuge it, and then dry it at 60°C for 12 hours to obtain manganese-based Prussian white material.

[0024] In this embodiment 5, the molar ratio of cesium chloride to manganese chloride tetrahydrate is 1:53, the molar ratio of sodium tungstate dihydrate to manganese chloride tetrahydrate is 1:63, and the molar ratio of sodium ferrocyanide decahydrate to manganese chloride tetrahydrate is 1:2.

[0025] Example 6: A method for preparing manganese-based Prussian white materials with improved cycling performance, specifically including the following steps: Step 1: Dissolve cesium chloride, manganese chloride tetrahydrate, and sodium tungstate dihydrate in 100 parts of deionized water, then add sodium citrate, stir, and add sodium hydroxide solution dropwise to adjust the pH to 7.5 to obtain a manganese salt mixed solution; Step 2: Add sodium ferrocyanide decahydrate to 100 parts of deionized water and stir to obtain a sodium ferrocyanide solution; Step 3: Add sodium ferrocyanide solution dropwise to the manganese salt mixture and stir to obtain a suspension; Step 4: Transfer the suspension to a high-pressure reactor, seal it, and place it in a drying oven. Perform a hydrothermal synthesis reaction at 160°C for 14 hours. After the reaction is complete, allow it to cool naturally, centrifuge it, and then dry it at 60°C for 12 hours to obtain manganese-based Prussian white material.

[0026] In this embodiment 6, the molar ratio of cesium chloride to manganese chloride tetrahydrate is 1:43, the molar ratio of sodium tungstate dihydrate to manganese chloride tetrahydrate is 1:53, and the molar ratio of sodium ferrocyanide decahydrate to manganese chloride tetrahydrate is 1:2.

[0027] Example 7: A method for preparing manganese-based Prussian white materials with improved cycling performance, specifically including the following steps: Step 1: Dissolve cesium chloride, manganese chloride tetrahydrate, and sodium tungstate dihydrate in 100 parts of deionized water, then add sodium citrate, stir, and add sodium hydroxide solution dropwise to adjust the pH to 7.5 to obtain a manganese salt mixed solution; Step 2: Add sodium ferrocyanide decahydrate to 100 parts of deionized water and stir to obtain a sodium ferrocyanide solution; Step 3: Add sodium ferrocyanide solution dropwise to the manganese salt mixture and stir to obtain a suspension; Step 4: Transfer the suspension to a high-pressure reactor, seal it, and place it in a drying oven. Perform a hydrothermal synthesis reaction at 160°C for 14 hours. After the reaction is complete, allow it to cool naturally, centrifuge it, and then dry it at 60°C for 12 hours to obtain manganese-based Prussian white material.

[0028] In this embodiment 7, the molar ratio of cesium chloride to manganese chloride tetrahydrate is 1:43, the molar ratio of sodium tungstate dihydrate to manganese chloride tetrahydrate is 1:58, and the molar ratio of sodium ferrocyanide decahydrate to manganese chloride tetrahydrate is 1:2.

[0029] Example 8: A method for preparing manganese-based Prussian white materials with improved cycling performance, specifically including the following steps: Step 1: Dissolve cesium chloride, manganese chloride tetrahydrate, and sodium tungstate dihydrate in 100 parts of deionized water, then add sodium citrate, stir, and add sodium hydroxide solution dropwise to adjust the pH to 7.5 to obtain a manganese salt mixed solution; Step 2: Add sodium ferrocyanide decahydrate to 100 parts of deionized water and stir to obtain a sodium ferrocyanide solution; Step 3: Add sodium ferrocyanide solution dropwise to the manganese salt mixture and stir to obtain a suspension; Step 4: Transfer the suspension to a high-pressure reactor, seal it, and place it in a drying oven. Perform a hydrothermal synthesis reaction at 160°C for 14 hours. After the reaction is complete, allow it to cool naturally, centrifuge it, and then dry it at 60°C for 12 hours to obtain manganese-based Prussian white material.

[0030] In this embodiment 8, the molar ratio of cesium chloride to manganese chloride tetrahydrate is 1:43, the molar ratio of sodium tungstate dihydrate to manganese chloride tetrahydrate is 1:68, and the molar ratio of sodium ferrocyanide decahydrate to manganese chloride tetrahydrate is 1:2.

[0031] Example 9: A method for preparing manganese-based Prussian white materials with improved cycling performance, specifically including the following steps: Step 1: Dissolve cesium chloride, manganese chloride tetrahydrate, and sodium tungstate dihydrate in 100 parts of deionized water, then add sodium citrate, stir, and add sodium hydroxide solution dropwise to adjust the pH to 7.5 to obtain a manganese salt mixed solution; Step 2: Add sodium ferrocyanide decahydrate to 100 parts of deionized water and stir to obtain a sodium ferrocyanide solution; Step 3: Add sodium ferrocyanide solution dropwise to the manganese salt mixture and stir to obtain a suspension; Step 4: Transfer the suspension to a high-pressure reactor, seal it, and place it in a drying oven. Perform a hydrothermal synthesis reaction at 160°C for 14 hours. After the reaction is complete, allow it to cool naturally, centrifuge it, and then dry it at 60°C for 12 hours to obtain manganese-based Prussian white material.

[0032] In this embodiment 9, the molar ratio of cesium chloride to manganese chloride tetrahydrate is 1:43, the molar ratio of sodium tungstate dihydrate to manganese chloride tetrahydrate is 1:73, and the molar ratio of sodium ferrocyanide decahydrate to manganese chloride tetrahydrate is 1:2.

[0033] Comparative Example 1: Based on Example 1, the difference between Comparative Example 1 and Example 1 is that cesium chloride is not introduced in step 1 to prepare manganese-based Prussian white material; specifically, the following steps are included: Step 1: Dissolve manganese chloride tetrahydrate and sodium tungstate dihydrate in 100 parts of deionized water, then add sodium citrate, stir, and add sodium hydroxide solution dropwise to adjust the pH to 7.5 to obtain a manganese salt mixed solution; Step 2: Add sodium ferrocyanide decahydrate to 100 parts of deionized water and stir to obtain a sodium ferrocyanide solution; Step 3: Add sodium ferrocyanide solution dropwise to the manganese salt mixture and stir to obtain a suspension; Step 4: Transfer the suspension to a high-pressure reactor, seal it, and place it in a drying oven. Perform a hydrothermal synthesis reaction at 160°C for 14 hours. After the reaction is complete, allow it to cool naturally, centrifuge it, and then dry it at 60°C for 12 hours to obtain manganese-based Prussian white material.

[0034] In Comparative Example 1, the molar ratio of sodium tungstate dihydrate to manganese chloride tetrahydrate is 1:63, and the molar ratio of sodium ferrocyanide decahydrate to manganese chloride tetrahydrate is 1:2.

[0035] Comparative Example 2: Based on Example 1, the difference between Comparative Example 2 and Example 1 is that sodium tungstate dihydrate is not introduced in step 1 to prepare manganese-based Prussian white material; specifically, the following steps are included: Step 1: Dissolve cesium chloride and manganese chloride tetrahydrate in 100 parts of deionized water, then add sodium citrate, stir, and add sodium hydroxide solution dropwise to adjust the pH to 7.5 to obtain a manganese salt mixed solution; Step 2: Add sodium ferrocyanide decahydrate to 100 parts of deionized water and stir to obtain a sodium ferrocyanide solution; Step 3: Add sodium ferrocyanide solution dropwise to the manganese salt mixture and stir to obtain a suspension; Step 4: Transfer the suspension to a high-pressure reactor, seal it, and place it in a drying oven. Perform a hydrothermal synthesis reaction at 160°C for 14 hours. After the reaction is complete, allow it to cool naturally, centrifuge it, and then dry it at 60°C for 12 hours to obtain manganese-based Prussian white material.

[0036] In Comparative Example 2, the molar ratio of cesium chloride to manganese chloride tetrahydrate is 1:43, and the molar ratio of sodium ferrocyanide decahydrate to manganese chloride tetrahydrate is 1:2.

[0037] Comparative Example 3: Based on Example 1, the difference between Comparative Example 3 and Example 1 is that: conventional manganese-based Prussian white material is used; specifically, the following steps are included: Step 1: Dissolve manganese chloride tetrahydrate in 100 parts of deionized water, then add sodium citrate, stir, and add sodium hydroxide solution dropwise to adjust the pH to 7.5 to obtain a manganese salt mixed solution; Step 2: Add sodium ferrocyanide decahydrate to 100 parts of deionized water and stir to obtain a sodium ferrocyanide solution; Step 3: Add sodium ferrocyanide solution dropwise to the manganese salt mixture and stir to obtain a suspension; Step 4: Transfer the suspension to a high-pressure reactor, seal it, and place it in a drying oven. Perform a hydrothermal synthesis reaction at 160°C for 14 hours. After the reaction is complete, allow it to cool naturally, centrifuge it, and then dry it at 60°C for 12 hours to obtain the traditional manganese-based Prussian white material.

[0038] In this Comparative Example 3, the molar ratio of sodium ferrocyanide decahydrate to manganese chloride tetrahydrate is 1:2.

[0039] Comparative Example 4: Based on Example 1, the difference between Comparative Example 4 and Example 1 is that in step 1, the molar ratio of cesium chloride and manganese chloride tetrahydrate is 5:43 to prepare manganese-based Prussian white material; the specific steps are as follows: Step 1: Dissolve cesium chloride, manganese chloride tetrahydrate, and sodium tungstate dihydrate in 100 parts of deionized water, then add sodium citrate, stir, and add sodium hydroxide solution dropwise to adjust the pH to 7.5 to obtain a manganese salt mixed solution; Step 2: Add sodium ferrocyanide decahydrate to 100 parts of deionized water and stir to obtain a sodium ferrocyanide solution; Step 3: Add sodium ferrocyanide solution dropwise to the manganese salt mixture and stir to obtain a suspension; Step 4: Transfer the suspension to a high-pressure reactor, seal it, and place it in a drying oven. Perform a hydrothermal synthesis reaction at 160°C for 14 hours. After the reaction is complete, allow it to cool naturally, centrifuge it, and then dry it at 60°C for 12 hours to obtain manganese-based Prussian white material.

[0040] In Comparative Example 4, the molar ratio of cesium chloride to manganese chloride tetrahydrate is 5:43, the molar ratio of sodium tungstate dihydrate to manganese chloride tetrahydrate is 1:63, and the molar ratio of sodium ferrocyanide decahydrate to manganese chloride tetrahydrate is 1:2.

[0041] Comparative Example 5: Based on Example 1, the difference between Comparative Example 5 and Example 1 is that in step 1, the molar ratio of sodium tungstate dihydrate to manganese chloride tetrahydrate is 5:63 to prepare manganese-based Prussian white material; the specific steps are as follows: Step 1: Dissolve cesium chloride, manganese chloride tetrahydrate, and sodium tungstate dihydrate in 100 parts of deionized water, then add sodium citrate, stir, and add sodium hydroxide solution dropwise to adjust the pH to 7.5 to obtain a manganese salt mixed solution; Step 2: Add sodium ferrocyanide decahydrate to 100 parts of deionized water and stir to obtain a sodium ferrocyanide solution; Step 3: Add sodium ferrocyanide solution dropwise to the manganese salt mixture and stir to obtain a suspension; Step 4: Transfer the suspension to a high-pressure reactor, seal it, and place it in a drying oven. Perform a hydrothermal synthesis reaction at 160°C for 14 hours. After the reaction is complete, allow it to cool naturally, centrifuge it, and then dry it at 60°C for 12 hours to obtain manganese-based Prussian white material.

[0042] In Comparative Example 5, the molar ratio of cesium chloride to manganese chloride tetrahydrate is 1:43, the molar ratio of sodium tungstate dihydrate to manganese chloride tetrahydrate is 5:63, and the molar ratio of sodium ferrocyanide decahydrate to manganese chloride tetrahydrate is 1:2.

[0043] Comparative Example 6: Based on Example 1, the difference between Comparative Example 6 and Example 1 is that in steps 1 and 2, ethylene glycol is used instead of deionized water as the solvent to prepare manganese-based Prussian white material; the specific steps are as follows: Step 1: Dissolve cesium chloride, manganese chloride tetrahydrate, and sodium tungstate dihydrate in 100 parts of ethylene glycol, then add sodium citrate, stir, and add sodium hydroxide solution dropwise to adjust the pH to 7.5 to obtain a manganese salt mixed solution; Step 2: Add sodium ferrocyanide decahydrate to 100 parts of ethylene glycol and stir to obtain a sodium ferrocyanide solution; Step 3: Add sodium ferrocyanide solution dropwise to the manganese salt mixture and stir to obtain a suspension; Step 4: Transfer the suspension to a high-pressure reactor, seal it, and place it in a drying oven. Perform a hydrothermal synthesis reaction at 160°C for 14 hours. After the reaction is complete, allow it to cool naturally, centrifuge it, and then dry it at 60°C for 12 hours to obtain manganese-based Prussian white material.

[0044] In Comparative Example 6, the molar ratio of cesium chloride to manganese chloride tetrahydrate is 1:43, the molar ratio of sodium tungstate dihydrate to manganese chloride tetrahydrate is 1:63, and the molar ratio of sodium ferrocyanide decahydrate to manganese chloride tetrahydrate is 1:2.

[0045] Performance testing: The manganese-based Prussian white material prepared in the examples and comparative examples was used as the positive electrode active material to assemble button cells, and the electrical performance was tested. Preparation of positive electrode slurry: The positive electrode active material is the manganese-based Prussian white material obtained in step 1, the binder is PVDF, and the conductive agent is Super P. The positive electrode active material, binder, and conductive agent are mixed in a mass ratio of 8:1:1. After being mixed evenly, the mixture is coated on a 12μm aluminum foil and vacuum dried at 140℃ for 1h.

[0046] Assembly of button batteries: The button cell battery casing is model 2032, the separator is 20μm, and the positive electrode is a uniformly coated positive electrode. In a glove box filled with argon gas, the button cell battery is assembled in the following order: battery casing - placing the positive electrode - adding electrolyte - placing the separator - adding electrolyte - placing the sodium plate - placing the spacer / spring - battery casing.

[0047] Test of cyclic charge-discharge performance: The button cell batteries were charged and discharged at a current of 0.2C using a button cell charge / discharge tester, with a voltage range of 2.5~3.8V. Cycle performance was tested for 10, 30, and 50 cycles. The test results are shown in the table below.

[0048] Conclusion: As can be seen from the data in the table above, in Examples 1-9, manganese-based Prussian white materials were modified by co-doping with cesium chloride and sodium tungstate dihydrate. Under the same preparation process and electrochemical testing conditions, the long-cycle capacity retention of materials with different doping ratios showed significant differences. Among them, the doping ratio used in Example 1 prepared the modified material with the best cycle stability.

[0049] Comparing the data from Example 1 and Comparative Examples 1-6, it can be seen that Comparative Example 1 only introduces Cs. + It can only suppress lattice distortion, but cannot solve the problem of insufficient framework bonding strength. Metal ion dissolution still occurs in the later stages of cycling, and the performance drops to 72.8% after 50 cycles; Comparative Example 2 only introduces W 6+It can only strengthen the framework, but lacks the support of large-radius cations. Lattice distortion during cycling still leads to framework cracking, and the performance drops to 66.9% after 50 cycles. Comparative Example 3 uses undoped traditional materials, which have neither distortion suppression nor framework strengthening. During cycling, Mn dissolution and structural collapse occur simultaneously, and the performance further drops to 57.1% after 50 cycles. Comparative Example 4 has excessive Cs. + It will occupy part of Na + The insertion site reduces the number of active sites, leading to a decrease in stability; Comparative Example 5: Excess W 6+ This can lead to excessive local lattice stress, generating new defects and accelerating structural degradation. In Comparative Example 6, ethylene glycol was used as a solvent to prepare manganese-based Prussian white material. Since ethylene glycol has a boiling point of 197°C during preparation, the ethylene glycol remaining in the active material will undergo electrolyte side reactions in the 2.5~3.8V voltage range during battery cycling, leading to cycle deterioration. In summary, this invention utilizes Cs... + With W 6+ The synergistic effect of dual doping simultaneously solves the problems of lattice distortion and framework dissolution during the cycling process of manganese-based Prussian white materials, achieving a significant improvement in cycling stability. Furthermore, by limiting the doping ratio and hydrothermal process parameters, a stable modified system is formed, which significantly improves cycling performance.

[0050] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing manganese-based Prussian white materials with improved cycling performance, characterized in that: Includes the following steps: Step 1: Dissolve cesium chloride, manganese chloride tetrahydrate, and sodium tungstate dihydrate in deionized water, then add sodium citrate, stir, and add sodium hydroxide solution dropwise to obtain a mixed manganese salt solution; Step 2: Add sodium ferrocyanide decahydrate to deionized water and stir to obtain a sodium ferrocyanide solution; Step 3: Add sodium ferrocyanide solution dropwise to the manganese salt mixture and stir to obtain a suspension; Step 4: The suspension is subjected to a hydrothermal synthesis reaction, cooled, centrifuged, and dried to obtain manganese-based Prussian white material; In step 1, the molar ratio of cesium chloride to manganese chloride tetrahydrate is 1:(30~55), and the molar ratio of sodium tungstate dihydrate to manganese chloride tetrahydrate is 1:(50~75).

2. The preparation method for improving the cycling performance of manganese-based Prussian white materials according to claim 1, characterized in that: In step 1, the molar ratio of cesium chloride to manganese chloride tetrahydrate is 1:(40~45); the molar ratio of sodium tungstate dihydrate to manganese chloride tetrahydrate is 1:(65~70).

3. The preparation method for improving the cycling performance of manganese-based Prussian white materials according to claim 1, characterized in that: The molar ratio of sodium ferrocyanide decahydrate to manganese chloride tetrahydrate is (0.8~1.2):(1.8~2.2).

4. The preparation method for improving the cycling performance of manganese-based Prussian white materials according to claim 1, characterized in that: The hydrothermal synthesis reaction is carried out at a temperature of 150-170°C for 12-16 hours.

5. The preparation method for improving the cycling performance of manganese-based Prussian white materials according to claim 1, characterized in that: The sodium hydroxide solution is used to adjust the pH of the manganese salt mixture to 7-8.

6. The manganese-based Prussian white material prepared by the method for improving the cycling performance of manganese-based Prussian white material according to any one of claims 1 to 5.

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