CN-116924369-B - Preparation method and application of battery-grade ferric hydrogen phosphate

Abstract

The invention provides a preparation method of battery-grade ferric hydrogen phosphate, which comprises the steps of adding a hydrogen peroxide solution and an ammonium dihydrogen phosphate solution into a ferrous sulfate solution for oxidation reaction to obtain a first intermediate solution, adding ammonia water into the first intermediate solution for pH value adjustment and aging reaction to obtain a second intermediate solution, and carrying out filter pressing and water washing on the second intermediate solution to obtain the battery-grade ferric hydrogen phosphate. The battery grade ferric hydrogen phosphate prepared by the preparation method provided by the invention has the characteristics of high purity, low sulfur and low impurity, and can be further used for preparing battery grade anhydrous ferric hydrogen phosphate and sodium ion positive electrode materials, so that better electrochemical performance can be obtained. Meanwhile, the preparation method has simple process flow and is suitable for large-scale industrial production. The invention also comprises a sodium ion battery using the sodium ion positive electrode material.

Inventors

• HE YA
• SUN JIE
• WEI YIHUA
• ZHANG YI
• HE JIANHAO
• HE ZHONGLIN

Assignees

• 湖北融通高科先进材料集团股份有限公司

Dates

Publication Date

20260512

Application Date

20230831

Claims (10)

1. 1. A method for preparing battery grade ferric hydrogen phosphate, the method comprising: S10, adding a hydrogen peroxide solution and an ammonium dihydrogen phosphate solution into a ferrous sulfate solution according to a certain proportion to perform oxidation reaction to obtain a first intermediate solution, wherein the molar ratio of the hydrogen peroxide to the ferrous sulfate in the ferrous sulfate solution is 0.5-1, and the molar ratio of the ammonium dihydrogen phosphate in the ammonium dihydrogen phosphate solution to the ferrous sulfate in the ferrous sulfate is 1.3-1.8; S20, adding ammonia water with a certain proportion into the first intermediate liquid to adjust the pH value and perform an aging reaction to obtain a second intermediate liquid; And S30, performing filter pressing and water washing on the second intermediate liquid to obtain the battery grade ferric hydrogen phosphate Fe 3 (HPO 4 ) 4 ·4H 2 O.
2. 2. The method for preparing battery-grade ferric hydrogen phosphate according to claim 1, wherein the dropping speed of the hydrogen peroxide solution is 50-80 mL/min, and/or the dropping speed of the monoammonium phosphate solution is 80-120 mL/min, and/or the oxidation reaction time is 1h, and/or the aging reaction time is 1 h-3 h.
3. 3. The method for preparing battery grade ferric hydrogen phosphate according to claim 1, wherein the mass fraction of the ammonium dihydrogen phosphate solution is 10% -25%.
4. 4. The method for preparing battery grade ferric hydrogen phosphate according to claim 1, wherein the pH value of the second intermediate solution is 1.8-3.0.
5. 5. A battery grade ferric hydrogen phosphate, characterized in that the battery grade ferric hydrogen phosphate is prepared according to the preparation method of any one of claims 1-4.
6. 6. The battery grade anhydrous ferric hydrogen phosphate is characterized in that the battery grade anhydrous ferric hydrogen phosphate is prepared by the following steps of flash evaporation drying, sintering, crushing and packaging the battery grade ferric hydrogen phosphate according to claim 5.
7. 7. The battery grade anhydrous ferric phosphate according to claim 6, wherein in the method for preparing the battery grade anhydrous ferric phosphate, the sintering is performed at 400-500 ℃ for 2 hours.
8. 8. The sodium ion positive electrode material is characterized by being prepared by mixing sodium carbonate and the battery-grade anhydrous ferric hydrogen phosphate according to the claim 6 or 7 according to a certain proportion, performing wet grinding, spray drying and sintering to obtain intermediate powder, and performing jet milling on the intermediate powder to obtain the Na 4 Fe 3 ((PO 4 ) 2 P 2 O 7 ) sodium ion positive electrode material.
9. 9. The sodium ion positive electrode material according to claim 8, wherein in the preparation method of the sodium ion positive electrode material, the molar ratio of the sodium carbonate to the battery-grade anhydrous ferric hydrogen phosphate is 2:1.
10. 10. A sodium ion battery, characterized in that it comprises a sodium ion positive electrode material according to claim 8 or 9.

Description

Preparation method and application of battery-grade ferric hydrogen phosphate Technical Field The invention relates to the technical field of batteries, in particular to a preparation method and application of battery-grade ferric hydrogen phosphate. Background As a representative secondary battery with the highest comprehensive performance, commercialization of a lithium ion battery can be traced back to the 90 th century, and research on the lithium ion battery has been conducted for many years to have a mature battery technology route. However, lithium ion batteries are difficult to support in the current growing energy storage market, limited by the abundance of lithium element crust. The working principle of the sodium ion battery is similar to that of a lithium ion battery, the sodium salt reserves are rich, the exploitation is simple, and the method has more advantages in the large-scale application direction in the subsequent energy storage field. The sodium ion battery mainly comprises a positive electrode, a negative electrode, electrolyte, a diaphragm and accessory parts. The positive and negative electrode materials are key to influence the performance of the sodium ion battery system, and the positive electrode materials are particularly prominent. The positive electrode materials of sodium ion batteries are classified into three main categories, namely transition metal oxides, prussian white/blue and polyanions. The positive electrode material of the polyanionic sodium ion battery has the advantages of stable structure and small volume change during charge and discharge. Among the positive electrode materials of polyanionic sodium ion batteries, iron-based sodium batteries have the advantages of lowest cost and no toxicity, wherein sodium iron pyrophosphate (Na 4Fe3(PO4)2P2O7) is the positive electrode material with the most potential in iron-based sodium electricity, and has the advantages of low cost, environmental friendliness, high theoretical capacity (129 mAh/g), excellent cycle performance and low volume expansion (about 4%). At present, aiming at the preparation process of ferric sodium phosphate, mainly iron phosphate is prepared as a raw material, and in the existing common preparation process, more realization means are available for preparing the iron phosphate. Experiments show that the ferric phosphate is used as a raw material to prepare the ferric sodium pyrophosphate has more advantages, but no mature process means is found aiming at the preparation of the ferric phosphate, and the technology still belongs to a relative blank stage in the industry. Disclosure of Invention In view of the above, the present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the invention provides a preparation method and application of battery-grade ferric hydrogen phosphate. The preparation method provided by the invention can be used for preparing the low-sulfur low-impurity battery-level ferric hydrogen phosphate, and further can be used for preparing the low-impurity ferric hydrogen phosphate and sodium ion positive electrode material, so that the utilization rate of the battery material can be improved. Meanwhile, the preparation method has simple process flow and is suitable for large-scale industrial production. To this end, in a first aspect, an embodiment of the present invention provides a method for preparing battery-grade ferric hydrogen phosphate, where the method includes: s10, adding a hydrogen peroxide solution and an ammonium dihydrogen phosphate solution into a ferrous sulfate solution according to a certain proportion to perform an oxidation reaction to obtain a first intermediate solution; S20, adding ammonia water with a certain proportion into the first intermediate liquid to adjust the pH value and perform an aging reaction to obtain a second intermediate liquid; and S30, performing filter pressing and water washing on the second intermediate liquid to obtain the battery-grade ferric hydrogen phosphate. Preferably, the dropping speed of the hydrogen peroxide solution is 50 mL/min-80 mL/min, and/or the dropping speed of the monoammonium phosphate solution is 80 mL/min-120 mL/min, and/or the oxidation reaction time is 1h, and/or the aging reaction time is 1 h-3 h. Preferably, the molar ratio of the hydrogen peroxide to the ferrous sulfate in the ferrous sulfate solution is 0.5-1. Preferably, the mass fraction of the monoammonium phosphate solution is 10% -25%. Preferably, the molar ratio of the ammonium dihydrogen phosphate in the ammonium dihydrogen phosphate solution to the ferrous sulfate in the ferrous sulfate is 1.3-1.8. Preferably, the pH value of the intermediate liquid is 1.8-3.0. In a second aspect, an embodiment of the present invention further provides a battery grade ferric hydrogen phosphate, which is prepared by the preparation method provided in the first aspect. In a third aspect, the embodiment of the inventi