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Preparation method of composite carbon-coated nanoscale lithium iron phosphate of three-dimensional network structure

A technology of network structure and lithium iron phosphate, applied in structural parts, electrical components, electrochemical generators, etc., can solve the problems of low temperature performance and poor rate performance, and achieve the effect of improving low temperature performance, high tap density and low cost

Active Publication Date: 2019-06-07
沈阳国科金能科技有限公司 +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] In view of the shortcomings of the current low-temperature performance and poor rate performance of lithium iron phosphate, the purpose of the present invention is to provide a preparation method for nano-scale lithium iron phosphate coated with a three-dimensional network structure composite carbon with excellent low-temperature performance and high-rate performance, so as to solve the problems of the prior art. Low-temperature performance and poor rate performance of lithium iron phosphate cathode materials for medium-sized lithium-ion batteries

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  • Preparation method of composite carbon-coated nanoscale lithium iron phosphate of three-dimensional network structure
  • Preparation method of composite carbon-coated nanoscale lithium iron phosphate of three-dimensional network structure
  • Preparation method of composite carbon-coated nanoscale lithium iron phosphate of three-dimensional network structure

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Embodiment 1

[0039] In this embodiment, the preparation method of lithium iron phosphate to improve low-temperature performance is as follows:

[0040](1) Weigh 18684.5g of ferric phosphate dihydrate, 7396.8g of lithium carbonate, 350g of food grade glucose, 350g of PEG1500 (polyethylene glycol), 159.7g of titanium dioxide, 180g of superconducting carbon black, 350g of graphene oxide, and 45L of deionized water . First add deionized water to the stainless steel kettle, then add lithium carbonate, iron phosphate dihydrate, food grade glucose, polyethylene glycol, titanium dioxide, stir and disperse in a ball mill for 3 hours, and then pass through a sand mill to refine it for 1 hour , adding superconducting carbon black and graphene oxide, and continuously ball milling and stirring in a ball mill for 1 hour to obtain a yellow-green precursor slurry, and the measured particle size of the slurry is D50=250nm. The precursor slurry was dried at a temperature of 120° C. for 10 h, and the obtain...

Embodiment 2

[0045] In this embodiment, the preparation method of lithium iron phosphate to improve low-temperature performance is as follows:

[0046] (1) Take by weighing iron powder 5473g, phosphoric acid (concentration 85wt%) 11528.7g, lithium hydroxide 2398.7g, food grade glucose 350g, PEG1500 (polyethylene glycol) 350g, titanium dioxide 159.7g, superconducting carbon black 180g, graphite oxide Alkene 350g, deionized water 45L. First add deionized water to the stainless steel kettle, then add lithium hydroxide, iron powder, phosphoric acid, food-grade glucose, polyethylene glycol, titanium dioxide, stir and disperse in a ball mill for 3 hours, and then pass through a sand mill to refine it for 1 After 1 hour, add superconducting carbon black and graphene oxide, and continue ball milling and stirring in a ball mill for 1 hour to obtain a yellow-green precursor slurry. The measured particle size of the slurry is D50=250nm. The precursor slurry was dried at a temperature of 120° C. for ...

Embodiment 3

[0050] In this embodiment, the preparation method of lithium iron phosphate to improve low-temperature performance is as follows:

[0051] (1) Weigh 5473g of iron powder, 11528.7g of phosphoric acid (concentration 85wt%), 2398.7g of lithium hydroxide, 300g of citric acid, 400g of PEG1500 (polyethylene glycol), 159.7g of titanium dioxide, 200g of superconducting carbon black, graphene oxide 400g, 45L deionized water. First add deionized water to the stainless steel kettle, then add lithium hydroxide, iron powder, phosphoric acid, citric acid, polyethylene glycol, titanium dioxide, stir and disperse in a ball mill for 3 hours, and then pass through a sand mill to refine it for 1 hour , adding superconducting carbon black and graphene oxide, and continuously ball milling and stirring in a ball mill for 1 hour to obtain a yellow-green precursor slurry, and the measured particle size of the slurry is D50=250nm. The precursor slurry was dried at a temperature of 120° C. for 10 h, a...

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Abstract

The invention relates to the field of lithium ion battery positive electrode materials, in particular to a preparation method of composite carbon-coated nanoscale lithium iron phosphate of a three-dimensional network structure. The method comprises the steps: based on a traditional lithium iron phosphate carbon coating process, performing ball-milling, mixing and dispersing of a lithium source, aniron source, a phosphorus source, a traditional carbon source, a metal ion dopant and dispersion solution; performing sanding refinement; adding superconductive carbon black and graphene oxide to themixed solution; performing drying after ball-milling and dispersion; performing high-temperature sintering of the dried product under the reducing atmosphere; performing cooling to obtain a graphene-containing precursor A; performing mixing and ball-milling of the precursor A, a carbon nano tube and superconducting carbon black to obtain a precursor B, and carrying out secondary high-temperaturesintering and crushing of the precursor B in a shielding gas environment to obtain the target lithium iron phosphate. By improving the carbon coating process, reducing the particle size of primary particles, enhancing the conductivity and the like, the method enables the prepared lithium iron phosphate serving as the positive electrode material of the lithium battery to have the excellent low-temperature performance and rate capability.

Description

technical field [0001] The invention relates to the field of positive electrode materials for lithium-ion batteries, in particular to a method for preparing nanoscale lithium iron phosphate coated with composite carbon with a three-dimensional network structure and excellent low-temperature performance and rate performance. Background technique [0002] In 1997, Goodenough's research group reported for the first time that the lithium-ion cathode material LiFePO 4 , its theoretical specific capacity is 170mAh / g. And LiFePO 4 With good cycle performance, it is currently the main lithium battery cathode material used in power batteries. In addition, the material also has a stable voltage platform, cheap and abundant raw materials, environmental friendliness, and low toxicity. [0003] LiFePO 4 It is an orthorhombic olivine structure, belonging to the Pmnb space group, and its lattice constant is LiFePO 4 Its crystal structure can still remain stable at 400°C, greatly impro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/58H01M4/587H01M10/0525
CPCY02E60/10
Inventor 庞晓晨唐昌平陈海涛曹贺杨林吴敏杰
Owner 沈阳国科金能科技有限公司