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CN-121974321-A - Carbon-titanium synergistic coated ferric sodium phosphate and preparation method thereof

CN121974321ACN 121974321 ACN121974321 ACN 121974321ACN-121974321-A

Abstract

The invention relates to carbon-titanium synergistic coated ferric sodium pyrophosphate and a preparation method thereof, belonging to the technical field of sodium ion batteries. The preparation method comprises the following steps of S1, uniformly mixing ferric phosphate, a sodium source, a carbon source and deionized water, coarse grinding, fine grinding and spray drying to obtain a composite precursor, and S2, sequentially carrying out rotary kiln pre-sintering, CVD (chemical vapor deposition) furnace carbon-titanium coating and rotary kiln sintering on the composite precursor to obtain the carbon-titanium synergistic coated ferric sodium phosphate. The continuous production is realized by uniformly heating the material body and fully rolling and contacting the material through the rotary kiln, the production efficiency and the yield are obviously improved, the density and the performance consistency of the sintered material are enhanced, the carbon-titanium cooperative coating is finished through the CVD vapor deposition technology, the uniformity of the coating layer is effectively enhanced, the carbon coating quality is improved, and the electrochemical performance of the material is comprehensively optimized.

Inventors

  • LI CHENWEI
  • LI LIANGJI
  • HAN PENG
  • QIAO SHAOHUA

Assignees

  • 无锡钠科能源科技有限公司

Dates

Publication Date
20260505
Application Date
20260130

Claims (10)

  1. 1. The preparation method of the carbon-titanium synergistic coated sodium ferric pyrophosphate is characterized by comprising the following steps of: s1, uniformly mixing ferric phosphate, a sodium source, a carbon source and deionized water, and carrying out coarse grinding, fine grinding and spray drying to obtain a composite precursor; s2, sequentially performing rotary kiln pre-sintering, carbon-titanium coating of a CVD (chemical vapor deposition) vapor deposition furnace and rotary kiln sintering on the composite precursor in S1 to obtain the sodium ferric pyrophosphate with the carbon-titanium synergistic coating.
  2. 2. The method for preparing carbon-titanium co-coated sodium iron pyrophosphate according to claim 1, characterized in that in S1, the sodium source is selected from sodium carbonate and/or sodium dihydrogen phosphate; And/or the carbon source is selected from one or more of glucose, sucrose, citric acid and polyethylene glycol; and/or the mass ratio of the ferric phosphate to the sodium source to the carbon source to the water is 1 (0.12-0.18): 0.06-0.1): 2.5-3.
  3. 3. The method for preparing carbon-titanium co-coated sodium iron phosphate according to claim 1, wherein in S1, the technological parameters of the coarse grinding are that the grinding medium is zirconia beads with the diameter of 0.4-0.5 μm, the frequency is 42-48 Hz, and the particle size D50 of the material after the coarse grinding is 3.8-4.4 μm.
  4. 4. The method for preparing carbon-titanium co-coated sodium iron phosphate according to claim 1, wherein in S1, the technological parameters of the fine grinding are that the grinding medium is zirconia beads with the diameter of 0.2-0.3 μm, the frequency is 42-48 Hz, and the particle size D50 of the fine ground material is 0.18-0.22 μm.
  5. 5. The method for preparing carbon-titanium co-coated sodium iron phosphate according to claim 1, wherein in S1, the spray drying process parameters are that the air inlet temperature is 240-250 ℃, the air outlet temperature is 95-105 ℃, the frequency is 48-52 Hz, and the particle size D50 of the spray dried material is 5-25 μm.
  6. 6. The method for preparing carbon-titanium co-coated sodium iron phosphate according to claim 1, wherein in S2, the pre-sintering is carried out in a protective atmosphere with a flow rate of 0.8-1.2L/min, heating to 340-360 ℃ at a rate of 4.8-5.2 ℃ and maintaining for 1.5-2.5 h, continuously heating to 390-410 ℃ and discharging.
  7. 7. The method for producing carbon-titanium co-coated sodium iron phosphate pyrophosphate according to claim 1, wherein in S2, said carbon-titanium coating is carried out by introducing a carbon source at a flow rate of 0.35m 3 /h-0.65m 3 /h, a titanium source at 0.12m 3 /h-0.33m 3 /h and a carrier gas at 0.8m 3 /h-1.7m 3 /h at 400 ℃ to 450 ℃ and 0.28MPa to 0.32 MPa.
  8. 8. The method for preparing carbon-titanium co-coated sodium iron pyrophosphate according to claim 7, wherein said carbon source is selected from acetylene and/or glycerol; And/or the titanium source is selected from isopropyl titanate and/or diisopropyl di (acetylacetonate) titanate; and/or, the carrier gas is nitrogen.
  9. 9. The method for preparing carbon-titanium co-coated sodium iron phosphate according to claim 1, wherein in S2, the sintering is performed by heating to 540-560 ℃ at a rate of 4.8-5.2 ℃ under a protective atmosphere with a flow rate of 0.8-1.2L/min, maintaining the temperature for 8-9 h, cooling, and discharging.
  10. 10. Carbon-titanium co-coated sodium iron pyrophosphate prepared by the method of any one of claims 1-9.

Description

Carbon-titanium synergistic coated ferric sodium phosphate and preparation method thereof Technical Field The invention belongs to the technical field of sodium ion batteries, and particularly relates to carbon-titanium co-coated ferric sodium pyrophosphate and a preparation method thereof. Background The ferric sodium phosphate (NFPP) serving as a novel sodium ion battery anode material has the remarkable advantages of high theoretical capacity, good reversibility of sodium ion deintercalation, low raw material cost, environmental friendliness and the like, and has wide application prospect in the field of large-scale energy storage. But the performance of the material is still optimized by modification means such as carbon coating, element doping and the like. The carbon coating can effectively improve the electronic conductivity of the material, inhibit particle agglomeration and relieve volume expansion, and the element doping can further improve the electrochemical cycling stability and the rate capability of the material by regulating and controlling the crystal structure of NFPP material, reducing the diffusion energy barrier of sodium ions, however, the traditional primary carbon coating has the defects of uneven thickness of the coating layer, weak binding force with a matrix and the like, and is difficult to fully exert the modification effect. Meanwhile, in the preparation process of NFPP materials, when carbon sources are added for mixing and element doping in front end grinding, the carbon sources and doping agents are easy to disperse unevenly and agglomerate to influence the uniformity of subsequent reactions, and the traditional roller kiln needs to use graphite sagger for feeding, so that material indexes are greatly fluctuated due to inconsistent material reactions at different positions in the sintering process, and meanwhile, the productivity is limited due to the limitation of the sagger loading amount of the materials. Based on the problems existing in the modification and preparation process of NFPP materials, the prior art improves the materials, but has the defects that the prior art improves the materials, the patent CN118197468A discloses a preparation method of a high-stability ferric sodium pyrophosphate positive electrode material, the method sequentially carries out primary low-temperature sintering, carbon coating and secondary high-temperature sintering through a sol-gel method, wherein the carbon coating adopts solid-phase carbon sources such as glucose, sucrose and the like for mixed coating, the crystallinity of the materials and the combination stability of a carbon layer are improved by means of secondary high-temperature sintering, and meanwhile, particle growth is inhibited, so that the stability of the circulating structure of the materials is enhanced, but the method has the problems of complex process, long preparation period and higher industrialization cost, and lacks continuous sintering equipment, the production efficiency is lower, the patent CN119029783A discloses a modified ferric sodium pyrophosphate positive electrode material and the preparation method thereof, adopts the technological processes of precursor coprecipitation, primary calcination, lithium-titanium codoping and secondary calcination, and improves the diffusion rate of sodium ions through lattice parameters of the lithium-titanium codoped materials, and the primary calcination is used for removing crystal water and impurity in the precursor, the secondary calcination is used for optimizing the crystal structure, and the whole production process is also low in the condition that the solid-phase doping efficiency is required to be increased, and the whole production process is also complicated, and has the complicated and has the disadvantages. In summary, the prior art still fails to effectively solve the problems of poor material performance, uneven material dispersion, inconsistent sintering reaction, limited productivity, low industrialization efficiency and high cost of NFPP in the preparation process, so that a continuous process is developed to realize the connection of presintering-carbon-titanium collaborative coating-high-temperature sintering, improve the uniformity of the material, strengthen the carbon coating quality and reduce the mass production cost, and the continuous process is a key direction for promoting the industrialized development of NFPP materials. Disclosure of Invention In order to solve the technical problems, the invention provides the carbon-titanium co-coated ferric sodium phosphate and the preparation method thereof, which adopts a rotary kiln to perform pre-sintering and sintering, realizes continuous production by means of the characteristics of uniform heating of a material body and sufficient rolling contact of materials, not only remarkably improves the production efficiency and yield, but also enhances the density and performance consistency of the sinter