A kind of spherical micronano iron phosphate/carbon composite material and preparation method thereof

A carbon composite material, micro-nano technology, applied in the field of lithium-ion batteries, can solve the problems of inconspicuous material modification, immaturity, uncontrollable mixing degree of reaction raw materials, etc.

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

AI Technical Summary

Problems solved by technology

[0003] Spherical lithium iron phosphate micro-nanostructure materials meet the design requirements of high energy density and high rate performance lithium-ion batteries, but most of the existing technologies directly use iron salts, phosphates, and carbon materials as raw materials to prepare lithium iron phosphate. On the one hand, the mixing degree of the reaction raw materials is uncontrollable, on the other hand, the prepared LiFePO 4 Cathode materials are not spherical
Most of the existing carbon coating technology is to add carbon source when the raw materials are mixed. Although the process is simple, it cannot guarantee the complete carbon coating of the material, and it is usually a carbon coating, which has no obvious effect on material modification.
Currently, the FePO 4 The production process is relatively rare and immature

Method used

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  • A kind of spherical micronano iron phosphate/carbon composite material and preparation method thereof
  • A kind of spherical micronano iron phosphate/carbon composite material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Weigh an equimolar amount of Fe(NO 3 ) 3 9H 2 O and H 3 PO 4 Prepare a 0.2mol / L mixed acid solution, measure a certain amount of ammonia water and dilute it to 0.5mol / L, and input the two in parallel and continuously into the crystallization reactor, the reaction temperature is 50°C, adjust and maintain the pH of the reaction system at about 2, The stirring intensity is 200r / s, and the reaction solution is naturally overflowed and discharged after the reactor is filled. After stirring and reacting for 10 hours, FePO is obtained after centrifugation, washing and drying. 4 ·xH 2 O powder. The precursor powder was heat-treated at 500 °C for 10 h to obtain nano-FePO 4 Precursor, nano-LiFePO prepared by carbothermal reduction method 4 / C cathode material. Weigh 12g of FePO 4 Precursor, 2.982g of Li 2 CO 3 Add 2.5g of sucrose and 5ml of deionized water to mix well, place in a tube furnace, feed high-purity nitrogen at 700°C for 16h, and obtain nano-LiFePO through h...

Embodiment 2

[0028] Weigh an equimolar amount of Fe(NO 3 ) 3 9H 2 O and H 3 PO 4 Make 0.2mol / L mixed acid solution, weigh FePO 4 After the polyacrylamide with a theoretical mass of 0.5wt% is dissolved in the acid solution, measure a certain amount of ammonia water and dilute it to 0.5mol / L, and input the two in parallel and continuously into the controlled crystallization reactor. The reaction temperature is 50°C, adjust and maintain the temperature of the reaction system. The pH is around 2, the stirring intensity is controlled to 200r / s, the reaction solution is naturally overflowed and discharged after the reactor is filled, and after stirring for 10 hours, it is centrifuged, washed and dried to obtain 0.5wt% PAM-FePO 4 ·xH 2 O powder. The precursor powder was heat-treated at 500 °C for 10 h to obtain PAM-FePO 4 Precursor, prepare the nanometer LiFePO that adopts PAM modification by the method for embodiment 1 4 / C cathode material. Such as figure 1 Shown, the obtained PAM-FeP...

Embodiment 3

[0030] Weigh an equimolar amount of Fe(NO 3 )3 9H 2 O and H 3 PO 4 Make 0.2mol / L mixed acid solution, weigh FePO 4 After the soluble starch with a theoretical mass of 0.5wt% is dissolved in the acid solution, measure a certain amount of ammonia water and dilute it to 0.5mol / L, and input the two in parallel and continuously into the controlled crystallization reactor. The reaction temperature is 50°C, and the pH of the reaction system is adjusted and maintained. At about 2, the stirring intensity is controlled to 200r / s, and the reaction solution is naturally overflowed and discharged after the reactor is filled. After stirring for 1 hour, it is centrifuged, washed and dried to obtain 0.5wt% soluble starch-FePO 4 ·xH 2 O powder. The precursor powder was heat-treated at 600 °C for 10 h to obtain spherical micro-nano FePO 4 Precursor, according to the method of embodiment 1, prepare the micronano LiFePO that adopts soluble starch modification 4 / C cathode material. Such a...

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PUM

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Abstract

The invention discloses a spherical micro-nano ferric phosphate / carbon composite material and a preparation method thereof. The preparation method comprises the following steps: (1) preparing aqueous solution of ferric salt and a phosphorous compound, wherein the mole ratio of the ferric element to the phosphorus element is (0.9-1.2): 1, and the solution concentration is 0.2-5 mol / L; (2) dispersing a high polymer material binder in the solution in the step (1), wherein the dosage of the high polymer material binder is 0.5-90 wt / % of the ferric salt; (3) adding the solution prepared in the step (2) into a reaction still, continuously adding alkali solution to ensure that the pH in the reaction still is kept in 2-4, and reacting at a temperature of 20-90DEG C for 1-60 hours to obtain a crystal water-containing spherical micro-nano ferric phosphate / carbon composite material; and (4) under an inert atmosphere, roasting the spherical micro-nano ferric phosphate / carbon composite material prepared in the step (3) at a temperature of 300-800DEG C for 3-12 hours, and cooling to obtain the product. According to the preparation method, the coating of carbon materials is realized, and a crucial role is played in subsequently preparing high-density high-performance lithium ion battery LiFePO4 anode materials.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, in particular to a spherical micro-nano iron phosphate / carbon composite material and a preparation method thereof. Background technique [0002] Iron phosphate (FePO 4 ) is a monoclinic crystal with a white or off-white powder appearance. It was originally widely used in fields such as agriculture, ceramic glass, steel and surface passivation. Subsequent studies have found that FePO 4 There are also applications in the fields of oxidative dehydrogenation catalysis, ion exchange, and electrochemical performance. In the application of electrochemical field, FePO 4 Can be used as LiFePO for the preparation of lithium-ion batteries 4 The skeleton material of the positive electrode material. Studies have shown that using FePO 4 Preparation of LiFePO as a precursor 4 The positive electrode material has the following advantages: (1) FePO 4 With a fixed Fe / P ratio, it is easier to ob...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/58H01M4/583H01M4/139H01M10/0525
CPCH01M4/139H01M4/366H01M4/5825H01M4/583H01M10/0525Y02E60/10
Inventor 杨改秦显忠高剑蔡飞鹏蒋波王波谭春晖
Owner ENERGY RES INST OF SHANDONG ACAD OF SCI
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