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CN-121983573-A - Manganese-based Prussian white material, preparation method and application

CN121983573ACN 121983573 ACN121983573 ACN 121983573ACN-121983573-A

Abstract

The invention provides a manganese-based Prussian white material, a preparation method and application thereof, which belong to the technical field of electrode materials, wherein the general formula of the manganese-based Prussian white material is Na n‑z A z Mn 1‑x M x [Fe(CN) 6 ] y , M is at least one of Fe, ni, cu, zn, co, A is K and Mg, n is 1.7< 2, x is more than or equal to 0.4 and less than or equal to 0.6, y is more than or equal to 0.9 and less than or equal to 1, z is more than or equal to 0.02 and less than or equal to 0.1, and the manganese-based Prussian white material has a rhombic phase structure. Sodium sulfate and sodium citrate are used as synthesis additives, the proportion of the sodium sulfate and the sodium citrate is optimized, the sodium content is improved, crystal defects and crystal water are reduced, the Na-site and Mn-site elements are doped, the structural stability in the charge and discharge process is maintained, and the removal of crystal water is promoted by Joule heat treatment, so that the optimization balance of capacity, multiplying power performance and cycle performance is realized.

Inventors

  • Sun dongzhou
  • HE WENQI
  • WEI JIWU
  • ZHANG LIN
  • HAN FEIFEI

Assignees

  • 鞍山辉虹颜料科技有限公司

Dates

Publication Date
20260505
Application Date
20260407

Claims (8)

  1. 1. The manganese-based Prussian white material is characterized by having a general formula of Na n-z A z Mn 1-x M x [Fe(CN) 6 ] y , wherein M is at least one of Fe, ni, cu, zn, co, A is K and Mg, wherein x is more than or equal to 1.7 and less than or equal to 2, x is more than or equal to 0.4 and less than or equal to 0.6, y is more than or equal to 0.9 and less than or equal to 1, z is more than or equal to 0.02 and less than or equal to 0.1, and the manganese-based Prussian white material has a rhombic phase structure.
  2. 2. The manganese-based Prussian white material according to claim 1, wherein the molar ratio of Mg to K in the manganese-based Prussian white material is 1.5-2.5:1.
  3. 3. A method for preparing a manganese-based doped Prussian white material based on any one of claims 1-2, comprising the steps of: S1, mixing sodium ferrocyanide with deionized water to obtain a solution I; s2, mixing soluble divalent manganese salt and soluble divalent M salt with deionized water, and adding sodium sulfate, sodium citrate, potassium salt and magnesium salt to obtain a solution II; S3, mixing the solution I and the solution II, performing coprecipitation reaction to obtain a suspension, and aging, separating and drying to obtain the manganese-base doped Prussian white material; And S4, performing Joule heat treatment and vacuum heat treatment on the manganese-doped Prussian white material to obtain the manganese-doped Prussian white material with the rhombic phase structure.
  4. 4. The method for preparing the manganese-based Prussian white material according to claim 3, wherein in the step S1, the concentration of the solution I is 0.1-0.5 mol/L.
  5. 5. The method for preparing the manganese-based Prussian white material is characterized in that in the step S2, the divalent manganese salt in the solution II is manganese nitrate, manganese sulfate or manganese chloride, the divalent M salt is nitrate, sulfate or chloride, and the total concentration of the divalent manganese salt and the divalent M salt is 0.1-0.5mol/L.
  6. 6. The preparation method of the manganese-based Prussian white material is characterized in that in the step S2, the ratio of the molar amount of sodium sulfate to the molar amount of sodium ferrocyanide is 2-3:1, the ratio of the molar amount of sodium citrate to the molar amount of sodium ferrocyanide is 4-6:1, the potassium salt is potassium nitrate, potassium sulfate or potassium chloride, the potassium salt is 0.05-0.3:1 of the molar amount of sodium ferrocyanide according to the molar amount of potassium ions, the magnesium salt is magnesium nitrate, magnesium sulfate or magnesium chloride, and the magnesium salt is 0.1-0.4:1 of the molar amount of sodium ferrocyanide according to the molar amount of magnesium ions.
  7. 7. The method for preparing the manganese-based Prussian white material according to claim 3, wherein in the step S3, the coprecipitation reaction temperature is 40-80 ℃, the aging temperature is 40-80 ℃ and the aging time is 2-20 hours, and the aged product is further subjected to separation and drying treatment.
  8. 8. Use of a manganese-based Prussian white material according to any one of claims 1-2 in a sodium ion battery.

Description

Manganese-based Prussian white material, preparation method and application Technical Field The invention belongs to the technical field of electrode materials, and particularly relates to a manganese-based Prussian white material, a preparation method and application thereof. Background In the field of sodium ion battery cathode materials, manganese-based Prussian white materials are widely studied due to an open frame structure, high operating voltage and high specific capacity. However, in the electrochemical cycle process of the existing manganese-based Prussian white material, manganese ions in the material can undergo valence state change, wherein a Jahn-Teller effect exists in the generated trivalent manganese ions Mn 3+, and the effect can cause Mn 3+ to be easy to generate lattice distortion in the charge-discharge process, so that a crystal frame is collapsed, and the capacity of the electrode material is rapidly attenuated and the cycle life is shortened. In addition, manganese-based Prussian white materials are generally synthesized in an aqueous environment, and crystal water is generated in the environment, and the existence of the crystal water can prevent rapid transmission of sodium ions, and the crystal water can be removed only by high-temperature and long-time heat treatment, but is easy to cause material decomposition due to high-temperature and long-time baking, and toxic HCN is generated, so that the structural stability is further reduced. Therefore, there is a need for a manganese-based Prussian white material capable of achieving high structural stability, low crystal water content, and high sodium ion conductivity. Disclosure of Invention Based on the technical problems, the invention aims to provide a manganese-based Prussian white material, a preparation method and application thereof, wherein sodium sulfate and sodium citrate are used as synthesis additives, the proportion of the materials is optimized, the sodium content is improved, crystal defects and crystal water are reduced, the Na-site and Mn-site elements are doped, the structural stability in the charging and discharging processes is maintained, and the removal of crystal water is promoted by Joule heat treatment, so that the optimization balance of capacity, multiplying power performance and cycle performance is realized. The specific technical scheme is as follows: The general formula of the manganese-based Prussian white doped material is Na n-zAzMn1-xMx[Fe(CN)6]y, wherein M is at least one of Fe, ni, cu, zn, co, A is K and Mg, x is more than or equal to 1.7 and less than or equal to 2, x is more than or equal to 0.4 and less than or equal to 0.6, y is more than or equal to 0.9 and less than or equal to 1, z is more than or equal to 0.02 and less than or equal to 0.1, and the manganese-based Prussian white doped material has a rhombic phase structure. In addition, the manganese-based Prussian white doped material in the technical scheme provided by the invention can also have the following additional technical characteristics: in the technical scheme, in the manganese-based Prussian white material, the molar ratio of Mg to K is 1.5-2.5:1. A preparation method of a manganese-based Prussian white material comprises the following steps: S1, mixing sodium ferrocyanide with deionized water to obtain a solution I; s2, mixing soluble divalent manganese salt and soluble divalent M salt with deionized water, and adding sodium sulfate, sodium citrate, potassium salt and magnesium salt to obtain a solution II; S3, mixing the solution I and the solution II, performing coprecipitation reaction to obtain a suspension, and aging, separating and drying to obtain the manganese-base doped Prussian white material; And S4, performing Joule heat treatment and vacuum heat treatment on the manganese-doped Prussian white material to obtain the manganese-doped Prussian white material with the rhombic phase structure. In the technical scheme, in the step S1, the concentration of the solution I is 0.1-0.5 mol/L. In the technical scheme, in the step S2, the divalent manganese salt in the solution II is manganese nitrate, manganese sulfate or manganese chloride, the divalent M salt is nitrate, sulfate or chloride, and the total concentration of the divalent manganese salt and the divalent M salt is 0.1-0.5mol/L. In the technical scheme, in the step S2, the ratio of the molar quantity of sodium sulfate to the molar quantity of sodium ferrocyanide is 2-3:1, the ratio of the molar quantity of sodium citrate to the molar quantity of sodium ferrocyanide is 4-6:1, the potassium salt is potassium nitrate, potassium sulfate or potassium chloride, the potassium salt is 0.05-0.3:1 of the molar quantity of sodium ferrocyanide according to the molar quantity of potassium ions, the magnesium salt is magnesium nitrate, magnesium sulfate or magnesium chloride, and the magnesium salt is 0.1-0.4:1 of the molar quantity of sodium ferrocyanide according to the mo