Preparation method and application of micro/nano structured LiFePO4 compound

A technology of micro-nano structure and function, applied in structural parts, chemical instruments and methods, phosphorus compounds, etc., can solve problems such as hindering free diffusion of ions, difficult coating process operation, low electronic conductivity, etc., and achieve good follow-up processing performance. , low price, high gram capacity

Inactive Publication Date: 2011-06-08
ZHENGZHOU BAK BATTERY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
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Problems solved by technology

Since the bond energy of the P-O bond is very large, PO 4 The tetrahedron is inert in the process of deintercalating lithium and can play a structural support role and is very stable, so LiFePO 4 It has good high temperature resistance and overcharge resistance; at the same time, it is precisely because of the adjacent FeO 6 The octahedrons are connected by common vertices, which hinders the Li + The free diffusion of ions eventually leads to lower electronic conductivity (Thackeray, M., Lithium-ion batteries: An unexpected conductor. Nat Mater 2002, 1, (2), 81-82.)
[0004] In recent years, the conductivity of the material has been improved by adding an organic carbon source for carbon coating during the preparation of the lithium iron phosphate material, but at the same time, the primary crystallization size of the material will be nanoscale.
The nanoscale is really helpful to the material's gram capacity, but it also brings great problems to the battery production and subsequent processes, mainly because the coating process is difficult to operate

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  • Preparation method and application of micro/nano structured LiFePO4 compound
  • Preparation method and application of micro/nano structured LiFePO4 compound
  • Preparation method and application of micro/nano structured LiFePO4 compound

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[0035] The preparation method of the invention is simple and easy, and the materials used are cheap and convenient for large-scale production. Prepared LiFePO 4 It has high purity and micro-nano structure, and has good electrochemical performance. When used as a cathode material for lithium-ion batteries, due to its structural characteristics of nano-scale primary crystal grains agglomerated to form micron-scale particles, on the one hand, it retains the advantages of high gram capacity of nano-scale materials, and on the other hand, micron-scale particles are convenient Subsequent coating operations.

[0036]The present invention will be further described in detail below through specific embodiments in conjunction with the accompanying drawings.

Embodiment 1

[0038] Fe:Li:PO 4 = The ratio of 1:1.05:1 is respectively called ferrous oxalate and LiOH·H 2 O, and NH 4 h 2 PO 4 After mixing evenly, add a small amount of Li which has the effect of molten salt 2 CO 3 , adding an appropriate amount of water to make a slurry, and then roasting under an argon atmosphere to obtain a lithium-ion cathode material - high-purity LiFePO 4 Compound; Li added above 2 CO 3 for LiFePO 4 1% of the product mass, the calcination temperature is 650°C, and the calcination time is 10 hours, then LiFePO with high-purity micro-nano structure can be obtained 4 compound.

Embodiment 2

[0040] Fe:Li:PO 4 = The ratio of 1:1.05:1 is respectively called ferrous oxalate and Li 2 CO 3 , and NH 4 h 2 PO 4 After mixing evenly, add a small amount of TiO with molten salt effect 2 , adding an appropriate amount of water to make a slurry, and then roasting under an argon atmosphere to obtain a lithium-ion cathode material - high-purity LiFePO 4 compound; the TiO added above 2 for LiFePO 4 3% of the product mass, the calcination temperature is 800°C, and the calcination time is 5 hours, the LiFePO with high-purity micro-nano structure can be obtained 4 compound.

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Abstract

The invention discloses a preparation method of micro/nano structured LiFePO4 compound and the method comprises: mixing Li source, divalent iron source, phosphate, and compound(s) with molten salt effects and calcinating the mixture in an inert atmosphere at a temperature of 550 to 850 DEG C, wherein the compound(s) with molten salt effects can change into molten compound(s) at a calcination temperature. The invention also discloses the applications of the LiFePO4 compound prepared by the above preparation method and the applications of the LiFePO4 compound as lithium ion battery cathode materials. The preparation method of the present invention is simple in operation and can be used to produce products with good electrochemical performance; and moreover the materials required are of low price, therefore the method is convenient for large scale production.

Description

technical field [0001] The present invention relates to a preparation method of a compound, the obtained compound and its application, in particular to a LiFePO with micro-nano structure 4 The preparation method of the compound, the prepared micro-nano structure LiFePO 4 Compounds and their applications as cathode materials for lithium-ion batteries. Background technique [0002] Lithium-ion secondary batteries are widely used in many fields such as mobile phones, notebook computers and portable electronic devices due to their long cycle life, stable discharge voltage, large specific capacity and no memory effect. In recent years, with the development of hybrid electric vehicles and secondary battery electric vehicles, higher requirements have been placed on the capacity and quality of rechargeable batteries. [0003] LiFePO 4 It is an existing compound in nature, and it is expected to become a new generation of lithium-ion battery cathode material because of its stable s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/45H01M4/58
CPCY02E60/12Y02E60/10
Inventor 相江峰
Owner ZHENGZHOU BAK BATTERY CO LTD
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