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High-electric-conductivity lithium iron phosphate material and preparation method thereof

A lithium iron phosphate, high conductivity technology, applied in circuits, electrical components, battery electrodes, etc., can solve the problems of poor conductivity of lithium iron phosphate materials, and achieve the effect of improving conductivity and improving rate performance.

Inactive Publication Date: 2019-02-01
TIANJIN XIANZHONG SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0011] The technical problem to be solved by the present invention is to provide a high-conductivity lithium iron phosphate material and its preparation method, through the compounding of various conductive materials and mechanisms, effectively solve the problem of poor conductivity of lithium iron phosphate materials

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  • High-electric-conductivity lithium iron phosphate material and preparation method thereof
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preparation example Construction

[0024] The preparation method of the high conductivity lithium iron phosphate material of the present invention comprises the following steps:

[0025] (1) Fully mix lithium iron phosphate with graphene slurry, vapor-phase grown carbon fiber VGCF or carbon nanotubes, and precursors containing noble metals in an aqueous solution, and then dry them by casting or spraying;

[0026] (2) The dried material is sintered at a high temperature for 4-24 hours in a nitrogen atmosphere at 400-900° C. to obtain a high-conductivity lithium iron phosphate material.

[0027] The added amount of graphene is 0.01%-2% of the mass of lithium iron phosphate.

[0028] The added amount of the vapor-phase grown carbon fiber VGCF or carbon nanotube is 0.1%-5% of the mass of lithium iron phosphate.

[0029] The precursor containing noble metal is a material that is cracked and subsequently sintered to obtain a high-conductivity elemental metal, and the amount added is 0.01%-1% of the mass of lithium i...

Embodiment 1

[0035] ⑴ 100g lithium iron phosphate material (particle size D 50 =2.1 μm) and 20g graphene slurry (graphene content is 10wt%), vapor phase grown carbon fiber (VGCF) 0.1g, platinum chloric acid (H 2 PtCl 6 ·6H 2 (0) 0.01g, add 100g of purified water, fully mix in liquid state, then dry into solid state at 120°C by casting method;

[0036] (2) The dried material is sintered at a high temperature for 24 hours under nitrogen atmosphere at 400° C. to obtain a lithium iron phosphate material.

[0037] The sintered material is subsequently crushed into finished products.

[0038] The electrical conductivity of the lithium iron phosphate material treated by the method is increased from the original 0.02S / cm to 1.1S / cm. Made a capacity type 18650 battery (3.2V / 1500mAh), under 3C rate discharge, the median voltage increased from 3.054V to 3.068V, an increase of 14mV. The maximum discharge rate is increased from 5C to 10C. It can be seen that the discharge rate of the battery syst...

Embodiment 2

[0040] ⑴ 1000Kg lithium iron phosphate material (particle size D 50 =1.9 μm) and 2Kg graphene slurry (graphene content is 5wt%), vapor phase grown carbon fiber (VGCF) 50Kg, silver nitrate (AgNO 3 ) 10Kg, add 2000Kg of purified water, fully mix in liquid state, and then dry into solid state at 200°C by spraying method;

[0041] (2) The dried material was sintered at a high temperature for 4 hours in a nitrogen atmosphere at 900° C. to obtain a lithium iron phosphate material.

[0042] The sintered material is subsequently crushed into finished products.

[0043] The electrical conductivity of the lithium iron phosphate material treated by the method is increased from the original 0.01S / cm to 1S / cm.

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Abstract

The invention discloses a high-electric-conductivity lithium iron phosphate material and a preparation method thereof. The method includes: (1) fully mixing lithium iron phosphate with graphene slurry, vapor-phase growth carbon fibers (VGCF) or carbon nanotubes, and a precursor comprising noble metals in a water solution and performing tape-casting drying or spray drying; (2) performing high-temperature sintering to the dried material at 400-900 DEG C for 4-24 h in a nitrogen atmosphere to obtain the high-electric-conductivity lithium iron phosphate material. The composition method comprehensively considers the high electric conductivity of the graphene, bridging effect of carbon fibers and extremely high conductivity of the noble metals, so that the inherent conductivity of the lithium iron phosphate material reaches the order of 1 S / cm, which can greatly reduce the abutment resistance between particles in a cathode material; therefore, the internal resistance of the battery is greatly reduced, and high-rate discharge performance of the lithium iron phosphate battery system is further greatly improved.

Description

technical field [0001] The invention relates to the field of preparation of cathode materials for lithium ion batteries, in particular to a high-conductivity lithium iron phosphate material and a preparation method thereof. Background technique [0002] Lithium iron phosphate (LiFePO 4 ) is a cathode material widely used in the current society. Due to its excellent safety, it is considered to be the preferred cathode material for electric vehicles in the future. However, due to the low conductivity of the lithium iron phosphate material (the bulk conductivity of the material is only 10 -9 S / cm), the magnification performance is not good, and the application is limited. [0003] How to improve the electrical conductivity of lithium iron phosphate materials has been a subject of constant concern in the scientific and industrial circles. At present, the general technology is to add glucose to lithium iron phosphate, form cracked carbon after high-temperature calcination, and...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/58H01M4/62H01M10/0525
CPCH01M4/362H01M4/5825H01M4/625H01M4/626H01M10/0525Y02E60/10
Inventor 郅晓科纪继坤
Owner TIANJIN XIANZHONG SCI & TECH