Preparation method of three-layer carbon-coated composite lithium iron phosphate cathode material

A technology of lithium iron phosphate and cathode material, applied in battery electrodes, electrical components, electrochemical generators, etc., can solve the problems of difficulty in Li+ insertion and extraction, low diffusion rate, etc., achieve uniform and dense coating effect, and improve electrical conductivity. , the effect of improving electrical conductivity

Active Publication Date: 2019-06-21
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

Nanoization is an effective solution to improve electrical performance. Due to the low diffusion rate of Li+ in lithium iron phosphate solids, LiFePO 4 The size of the particle radius has a great influence on the electrode capacity. The larger the particle radius, the longer the diffusion distance of Li+ in the solid phase, and the more difficult it is for Li+ to intercalate and deintercalate. LiFePO 4 The capacity to play is more limited

Method used

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  • Preparation method of three-layer carbon-coated composite lithium iron phosphate cathode material
  • Preparation method of three-layer carbon-coated composite lithium iron phosphate cathode material
  • Preparation method of three-layer carbon-coated composite lithium iron phosphate cathode material

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Embodiment 1

[0049] Such as figure 1 As shown, the manufacturing process of the three-layer carbon-coated composite lithium iron phosphate cathode material in this embodiment is as follows:

[0050] Take by weighing 7200g anhydrous ferric phosphate (FePO 4 ), 1818g lithium carbonate (Li 2 CO 3 ), 400g glucose, 60g polyvinylpyrrolidone (PVP). Add 10000ml of deionized water to the stirring mill, under stirring, add FePO 4 and Li 2 CO 3 Disperse for 30min. Continue to slowly add glucose and PVP, and obtain a slurry after dispersing for 30 minutes. The above slurry was transferred into a sand mill, and the precursor slurry with an average particle size of 350 nm was obtained by sand grinding in the sand mill. The precursor slurry was transported to the spray dryer, the inlet temperature was set to 240°C, and the outlet temperature was set to 100°C to obtain the precursor powder. Place the precursor powder in a sintering furnace protected by high-purity nitrogen (volume purity 99.999%)...

Embodiment 2

[0060] Such as figure 1 As shown, the manufacturing process of the three-layer carbon-coated composite lithium iron phosphate cathode material in this embodiment is as follows:

[0061] Take by weighing 7200g anhydrous ferric phosphate (FePO 4 ), 1818g lithium carbonate (Li 2 CO 3 ), 15g superconducting carbon black, 60g polyvinylpyrrolidone (PVP). Add 10000ml of pure water to the stirring mill, and add FePO 4 and Li 2 CO 3 Disperse for 30min. Continue to slowly add superconducting carbon black and PVP, and obtain a slurry after dispersing for 30 minutes. The above slurry was transferred into a sand mill, and the precursor slurry with an average particle size of 350 nm was obtained by sand grinding in the sand mill. The precursor slurry was transported to the spray dryer, the inlet temperature was set to 240°C, and the outlet temperature was set to 100°C to obtain the precursor powder. Place the precursor powder in a sintering furnace protected by high-purity nitrogen...

Embodiment 3

[0066] Such as figure 1 As shown, the manufacturing process of the three-layer carbon-coated composite lithium iron phosphate cathode material in this embodiment is as follows:

[0067] Take by weighing 7200g anhydrous ferric phosphate (FePO 4 ), 1818g lithium carbonate (Li 2 CO 3 ), 30gPEG, 60g polyvinylpyrrolidone (PVP). Add 10000ml of pure water to the stirring mill, and add FePO 4 and Li 2 CO 3Disperse for 30min. Continue to slowly add PEG and PVP and disperse for 30 minutes to obtain a slurry. The above slurry was transferred into a sand mill, and the precursor slurry with an average particle size of 350 nm was obtained by sand grinding in the sand mill. The precursor slurry was transported to the spray dryer, the inlet temperature was set to 240°C, and the outlet temperature was set to 100°C to obtain the precursor powder. Place the precursor powder in a sintering furnace protected by high-purity nitrogen (volume purity 99.999%), heat up to 400°C at a rate of 5°...

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Abstract

The invention belongs to the technical field of the lithium ion battery cathode material, specifically a preparation method of a three-layer carbon-coated composite lithium iron phosphate cathode material. The method comprises the following steps: stirring and pre-dispersing ferro-phosphorous source, a lithium source, organic carbon source and dispersing agent in pure water, sanding through a sanding machine to obtain a precursor slurry; performing spray-drying pelleting to obtain spherical precursor powder; placing the precursor powder in a sintering furnace with protection atmosphere to perform low-temperature sintering, and cooling to room temperature; dispersing the sintered product, super-conducting carbon black, and dispersing agent in the pure water, and then performing sanding, spraying pelleting and sintering; and finally adding polyethylene glycol, the dispersing agent and the deionized water, firstly dispersing and sanding to prepare slurry, and then performing spraying pelleting, sintering and crushing to obtain the finished product. Three carbon sources are used for coating to prepare the lithium iron phosphate cathode material; compared with the single carbon source coating on the traditional lithium iron phosphate material, the coating of three carbon sources can greatly improve the own conducting performance of the material.

Description

technical field [0001] The invention belongs to the technical field of lithium ion battery cathode materials, in particular to a preparation method of a three-layer carbon-coated composite lithium iron phosphate cathode material. Background technique [0002] Since the advent of lithium-ion batteries in the early 1990s, they have been recognized as the most promising power and energy storage batteries due to their high energy density and good cycle performance. According to the comparative study of the American Advanced Battery Consortium, lithium-ion batteries are the secondary battery system that can best meet the medium and long-term development goals of electric vehicles so far. As a key component of lithium-ion batteries, positive electrode materials are key factors that determine battery safety, capacity, and price. Traditional positive electrode materials such as lithium manganese oxide, lithium cobalt oxide, and lithium nickel oxide, etc., are subject to cost, safety...

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 曹贺唐昌平胡广剑庞晓晨杨林陈海涛
Owner 沈阳国科金能科技有限公司
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