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A kind of spherical graphene/fepo4 composite material and preparation method thereof

A spherical graphite and composite material technology, applied in the field of lithium ion batteries, can solve the problems of inability to guarantee the integrity of graphene coating, limited improvement in material properties, etc. Effect

Active Publication Date: 2018-06-22
ENERGY RES INST OF SHANDONG ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, there are many literatures on graphene-coated lithium iron phosphate, but most of them are coated with graphene on the surface of lithium iron phosphate during the generation process, which cannot guarantee the integrity of graphene coating, and affects the material performance. limited improvement

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Get 3g graphene and ultrasonically disperse evenly in the reactor, weigh the Fe(NO 3 ) 3 9H 2 O and H 3 PO 4 Prepare a 0.2mol / L mixed acid solution and continuously input it into the above reaction kettle, control the reaction temperature at 60°C, adjust the pH of the solution to 2 with 0.5mol / L dilute ammonia water, control the stirring intensity at 200r / s, and obtain a yellow color after 5 hours of reaction Emulsion i.e. primary grown graphene / FePO 4 2H 2 O, the concentrated primary grown graphene / FePO 4 2H 2 O is uniformly dispersed in the reaction kettle, and the above-mentioned mixed acid solution and lye containing iron salt and phosphorus compound are flowed into the above-mentioned reaction kettle and adjusted to pH = 2, and the precipitate is filtered and washed after stirring for 5 hours. and dried to obtain secondary grown spherical graphene / FePO 4 2H 2 O. The precursor powder was heat-treated at 500 °C for 10 h under an inert atmosphere to obtain s...

Embodiment 2

[0028] Take 3g of graphene and ultrasonically disperse it uniformly in the reactor, and weigh the equimolar FeSO 4 with H 3 PO 4 Prepare a 0.4mol / L mixed acid solution and continuously input it into the above reaction kettle, control the reaction temperature at 60°C, adjust the pH of the solution to 3 with 1.0mol / L dilute ammonia water, control the stirring intensity at 200r / s, and obtain a yellow color after 5 hours of reaction Emulsion i.e. primary grown graphene / FePO 4 2H 2 O, the concentrated primary grown graphene / FePO 4 2H 2 O is uniformly dispersed in the reaction kettle, and the above-mentioned mixed acid solution and lye containing iron salt and phosphorus-containing compound are flowed into the above-mentioned reaction kettle and adjusted to pH=3, and after stirring and reacting for 5 hours, the precipitate is suction filtered, Secondarily grown spherical graphene / FePO after washing and drying 4 2H 2 O. The precursor powder was heat-treated at 500 °C for 10 h...

Embodiment 3

[0031] Get 5g of graphene ultrasonic vibration and evenly disperse in the reactor, weigh the Fe(NO 3 ) 3 9H 2 O and H 3 PO 4 Prepare a 0.4mol / L mixed acid solution and continuously input it into the above reaction kettle, control the reaction temperature at 60°C, adjust the pH of the solution to 2 with 1.0mol / L dilute ammonia water, control the stirring intensity at 200r / s, and obtain a yellow color after 5 hours of reaction Emulsion i.e. primary grown graphene / FePO 4 2H 2 O, the concentrated primary grown graphene / FePO 4 2H 2 O is uniformly dispersed in the reaction kettle, and the above-mentioned mixed acid solution and lye containing iron salt and phosphorus compound are flowed into the above-mentioned reaction kettle and adjusted to pH=2, and the precipitate is filtered by suction after stirring for 5 hours. Secondarily grown spherical graphene / FePO after washing and drying 4 2H 2 O. The precursor powder was heat-treated at 600 °C for 10 h under an inert atmosphe...

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Abstract

The invention discloses a spherical graphene / FePO4 composite and a preparing method thereof. The preparing method includes the following steps of (1) preparing an aqueous solution of ferric salt and a phosphorous compound; 2, adding the aqueous solution and an alkaline solution into a reactor kettle in a parallel-flow mode, keeping the pH being 2-4 and the temperature being 20-90 DEG C, and obtaining primary-growth graphene / FePO4.2H2O; 3, concentrating and dispersing the prepared primary-growth graphene / FePO4.2H2O into the reaction kettle, repeating operation in the step 2, and obtaining a secondary-growth spherical graphene / FePO4.2H2O composite through suction filtration, washing and drying; 4, sintering the prepared secondary-growth graphene / FePO4.2H2O composite under inert gas to obtain the spherical graphene / FePO4 composite. According to the spherical graphene / FePO4 composite and the preparing method, graphene is directly introduced into preparing of FePO4, and particles of the prepared spherical graphene / FePO4 composite are regular in shape, even in granularity and high in tap density. The whole preparing technology is rapid and convenient to operate, and the spherical graphene / FePO4 composite and the preparing method are of great application significance in preparing of a graphene / lithium iron phosphate composite.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, in particular to a spherical graphene / FePO 4 The composite material and its preparation method are used as the precursor of the lithium iron phosphate cathode material of the lithium ion battery. Background technique [0002] Olivine-structured lithium iron phosphate (LiFePO 4 ) because of its wide source of raw materials, low cost, environmental friendliness and high theoretical specific capacity (170mAh·g -1 ), good thermal stability and cycle performance, and many other advantages, it is one of the most promising cathode materials for lithium-ion batteries. But due to its inherent crystal structure, LiFePO 4 have very low electronic conductivity and Li + Diffusion coefficient leads to its poor high-current discharge performance, which restricts its wide application. Currently improved LiFePO 4 Conductivity studies mainly focus on two aspects of carbon coating and metal ion ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/58H01M4/62H01M10/0525
CPCH01M4/5825H01M4/625H01M10/0525Y02E60/10
Inventor 秦显忠杨改高剑蔡飞鹏蒋波王波谭春晖
Owner ENERGY RES INST OF SHANDONG ACAD OF SCI