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Preparation method of lithium iron phosphate coated with lithium iron oxide

A technology of coating lithium iron phosphate and lithium ferrite, which is applied in the direction of electrical components, electrochemical generators, battery electrodes, etc., can solve the problems of poor conductivity and low compaction density of lithium iron phosphate, and achieve high compaction density, The effect of low cost and high capacity

Active Publication Date: 2019-06-28
SICHUAN LOMON PHOSPHORUS CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, the biggest disadvantage of lithium iron phosphate is its poor conductivity, so the conventional treatment method is to coat carbon, but after coating carbon, the compaction density of lithium iron phosphate will be low, so there is an urgent need for iron phosphate with higher compaction density and high capacity Lithium material

Method used

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  • Preparation method of lithium iron phosphate coated with lithium iron oxide
  • Preparation method of lithium iron phosphate coated with lithium iron oxide
  • Preparation method of lithium iron phosphate coated with lithium iron oxide

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Embodiment 1

[0034] A preparation method for lithium iron phosphate coated lithium iron phosphate, comprising the following steps:

[0035] Add ferrous sulfate solution, lithium hydroxide solution, ammonium monohydrogen phosphate solution, and titanyl sulfate solution together into the high-pressure reactor, and under stirring conditions, hydrothermal reaction is carried out. The hydrothermal reaction temperature is 285°C and the pressure is 0.45MPa. The reaction was carried out for 5.5 hours, then the pressure was released and cooled, and the slurry was poured out; the concentrations of ferrous sulfate solution, lithium hydroxide solution, ammonium monohydrogen phosphate solution, and titanyl sulfate solution were 1.8mol / L, 1.5mol / L, 2.5mol / L and 0.8mol / L, ferrous sulfate and lithium hydroxide are battery grade, ammonium monohydrogen phosphate is food grade, titanyl sulfate is reagent pure, ferrous sulfate, lithium hydroxide, ammonium monohydrogen phosphate and The molar ratio of titanyl ...

Embodiment 2

[0050] A preparation method for lithium iron phosphate coated lithium iron phosphate, comprising the following steps:

[0051] (1) Add ferrous sulfate solution, lithium hydroxide solution, ammonium monohydrogen phosphate solution, and titanyl sulfate solution together into the autoclave, and conduct hydrothermal reaction under stirring conditions. The hydrothermal reaction temperature is 280°C and the pressure React at 0.5MPa for 6h, then release the pressure and cool, and pour out the slurry;

[0052] (2) Add the slurry obtained in step (1) into a dispersant, stir for 20 minutes, and use it as a bottom liquid, then prepare ferric chloride solution, ammonium bicarbonate solution and lithium hydroxide solution, and mix ferric chloride solution, ammonium bicarbonate solution and lithium hydroxide solution were added to the bottom solution in parallel, the pH of the feeding process was maintained at 7.5, the temperature was 50°C, and the feeding time was 3 hours. The lithium con...

Embodiment 3

[0063] A preparation method for lithium iron phosphate coated lithium iron phosphate, comprising the following steps:

[0064] (1) Add ferrous sulfate solution, lithium hydroxide solution, ammonium monohydrogen phosphate solution, and titanyl sulfate solution together into the autoclave, and perform hydrothermal reaction under stirring conditions. The hydrothermal reaction temperature is 295°C and the pressure React at 0.5MPa for 5.5h, then release the pressure and cool, and pour out the slurry;

[0065] (2) Add the slurry obtained in step (1) into a dispersant, stir for 25 minutes, and use it as the bottom liquid, then prepare ferric chloride solution, ammonium bicarbonate solution and lithium hydroxide solution, and under stirring conditions, ferric chloride Solution, ammonium bicarbonate solution and lithium hydroxide solution were added to the bottom solution in parallel, the pH of the feeding process was maintained at 7.3, the temperature was 50°C, and the feeding time wa...

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Abstract

The invention discloses a preparation method of lithium iron phosphate coated with lithium ferrite. According to the method, the ferrous sulfate solution, the lithium hydroxide solution, the ammoniumdihydrogen phosphate solution and the titanyl sulfate solution are added into a high-pressure reaction kettle together, and then the hydrothermal reaction is carried out to obtain the slurry. A dispersing agent is added into the slurry, and a ferric chloride solution, an ammonium bicarbonate solution and a lithium hydroxide solution are merged and added into a base solution in a parallel flow manner. After the adding of above materials, the carbon dioxide is introduced and then the filtering is carried out. Obtained filter residues are heated and washed with pure water. A precursor is obtainedthrough drying and screening the residues and removing iron in the residues. The obtained precursor is calcined in an inert atmosphere, and the calcined material is subjected to smashing, screening and iron removing through the air flow to obtain lithium iron phosphate coated with lithium iron oxide. The method is simple and low in cost. The amorphous titanium-doped lithium iron phosphate is prepared through the hydrothermal method. After that, lithium iron phosphate coated with lithium iron oxide is obtained through precipitation. Finally, the lithium iron phosphate coated with lithium ironoxide is obtained through calcination. The obtained lithium iron phosphate is high in capacity and high in compaction density.

Description

technical field [0001] The invention relates to a preparation method of lithium iron phosphate coated with lithium iron phosphate, belonging to the technical field of lithium battery cathode materials. Background technique [0002] Lithium iron phosphate is a new lithium ion battery electrode material. It is characterized by large discharge capacity, low price, non-toxicity, and no environmental pollution. Countries around the world are successively realizing industrialized production. However, its tap density is low, which affects the capacitance. The main production method is high-temperature solid-phase synthesis, and the product index is relatively stable. The performance of lithium-ion batteries mainly depends on the positive and negative electrode materials. Lithium iron phosphate as the positive electrode material of lithium-ion batteries has only appeared in recent years. The domestic development of large-capacity lithium iron phosphate batteries was in July 2005....

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/58H01M4/62H01M10/0525
CPCY02E60/10
Inventor 王柯娜
Owner SICHUAN LOMON PHOSPHORUS CHEM
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