A kind of preparation method of lithium iron phosphate positive electrode material of lithium ion battery

A technology for lithium-ion batteries and lithium iron phosphate, which is applied in the field of preparation of lithium-ion battery materials, can solve problems such as uneven dispersion of conductive agents and affect the conductivity of positive active materials, achieve excellent conductivity, improve utilization efficiency, and increase accumulation effect of density

Inactive Publication Date: 2011-12-28
IRICO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, when using the solid-phase method, it is difficult to mix various solid components fully, so the various components in the obtained lithium iron phosphate positive electrode active material, especially the conductive agent, are not uniformly dispersed, which directly affects the conductivity of the positive electrode active material.

Method used

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  • A kind of preparation method of lithium iron phosphate positive electrode material of lithium ion battery
  • A kind of preparation method of lithium iron phosphate positive electrode material of lithium ion battery
  • A kind of preparation method of lithium iron phosphate positive electrode material of lithium ion battery

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Effect test

Embodiment 1

[0029] 1) Preparation of nanoscale lithium iron phosphate primary particles:

[0030] According to the molar ratio of P:Fe:Li=1:1:3, weigh ammonium phosphate, ferrous acetate, and lithium fluoride, dissolve them in water respectively, use magnetic stirring to fully dissolve the raw materials, and then pour the three solutions into the reactor Internal mixing, then use mechanical stirring (rotating speed is 300 rpm) to make the three solutions fully mixed to form a mixed solution; add ethylene glycol to the mixed solution to improve the reaction temperature of the mixed solution, the volume of the ethylene glycol and the mixed solution The volume ratio of the solution is 2: 3, and the pH of the mixed solution is adjusted to be 6.5-8.6. When the temperature of the mixed solution reaches 110-130° C., the reactor is sealed, and nitrogen gas is introduced therein. When a stable precipitate is formed at the bottom of the mixed solution, Separating the precipitate to obtain nanoscale...

Embodiment 2

[0038] 1) Preparation of nanoscale lithium iron phosphate primary particles:

[0039] According to the molar ratio of P:Fe:Li=1:1:3, weigh ammonium dihydrogen phosphate, iron nitrate, and lithium hydroxide, dissolve them in water respectively, use magnetic stirring to fully dissolve the raw materials, and then pour the three solutions into the reaction Mix in the container, then use mechanical stirring (rotating speed is 500 rev / min) to make three kinds of solutions fully mix, form mixed solution; Add ethylene glycol in mixed solution, improve the reaction temperature of mixed solution, the volume of described ethylene glycol The volume ratio to the mixed solution is 2:3, adjust the pH of the mixed solution to 6.8-8.2, when the temperature of the mixed solution reaches 115-125°C, seal the reactor, and then feed nitrogen into it, when the bottom of the mixed solution forms a stable During the precipitation, the precipitate is separated to obtain the primary particle of nano-sca...

Embodiment 3

[0047] 1) Preparation of nanoscale lithium iron phosphate primary particles:

[0048] According to the molar ratio of P:Fe:Li=1:1:3, weigh lithium dihydrogen phosphate, iron hydroxide, and lithium carbonate, dissolve them in water respectively, use magnetic stirring to fully dissolve the raw materials, and then pour the three solutions into the reaction Mix in the container, then use mechanical stirring (rotating speed is 400 rpm) to make the three solutions fully mix to form a mixed solution; add ethylene glycol in the mixed solution to improve the reaction temperature of the mixed solution, the volume of the ethylene glycol is the same as The volume ratio of the mixed solution is 2: 3, and the pH of the adjusted mixed solution is 7.0-7.5. When the temperature of the mixed solution reaches 120° C., the reactor is sealed, and then feeds nitrogen therein. When a stable precipitate is formed at the bottom of the mixed solution, Separating the precipitate to obtain nanoscale lith...

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Abstract

The invention discloses a preparation method of lithium iron phosphate, a positive electrode material of a lithium ion battery, comprising the following steps: 1) preparing nanoscale primary particles of lithium iron phosphate: weighing according to the molar ratio of P:Fe:Li=1:1:3 Phosphate, iron salt, lithium salt, using the co-precipitation method to prepare nano-scale lithium iron phosphate primary particles; 2) drying and carbon coating: dry the primary lithium iron phosphate particles prepared in step 1) and add graphene powder , ball milling to obtain secondary particles; 3) sintering of the lithium iron phosphate precursor: roasting the secondary particles obtained in step 2) from ball milling to obtain lithium iron phosphate, a cathode material for lithium ion batteries. In the present invention, graphene is added for carbon coating, which can greatly improve the electrical conductivity of the lithium iron phosphate material, and facilitate the entry and exit of electrons on the surface of the material particles; an extremely thin coating layer is formed on the surface of the material, which greatly improves the packing density of the material and makes phosphoric acid Iron-lithium particles can be stacked more orderly, greatly improving the ability of Li+ and electrons to enter and exit.

Description

technical field [0001] The invention relates to a preparation method of a lithium ion battery material, in particular to a preparation method of lithium iron phosphate, a cathode material of a lithium ion battery. Background technique [0002] Since the late 1990s, olivine-type LiFePO 4 The study of cathode materials has attracted the attention of many researchers. Lithium iron phosphate has high theoretical capacity (170mAh / g), high working voltage (voltage platform around 3.5V), appropriate mass density (3.64g / cm 3 ), small self-discharge, LiFePO at low current density 4 Li in + Almost 100% intercalation / deintercalation, long cycle life, good cycle performance, no memory effect, low price, good thermal stability, and environmental friendliness are expected to become a new generation of lithium-ion battery cathode materials. [0003] Lithium-ion batteries are widely used in various electronic devices, such as notebook computers, mobile batteries, digital cameras, portab...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/62H01M4/58
CPCY02E60/12Y02E60/10
Inventor 刘石磊
Owner IRICO
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