Graphene-coated lithium iron phosphate composite material and preparation method thereof

A technology of graphene-coated lithium iron phosphate and composite materials, which is applied in the field of graphene-coated lithium iron phosphate composite materials and its preparation, can solve the problems of shortened diffusion distance, high preparation cost, increased specific surface of nanoparticles, etc. Improve rate performance and its low temperature performance, excellent dispersion characteristics, and improve production efficiency
CN112694078APending Publication Date: 2021-04-23SHAANXI COAL & CHEM TECH INST
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
SHAANXI COAL & CHEM TECH INST
Publication Date
2021-04-23

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Abstract

The invention discloses a graphene-coated lithium iron phosphate composite material and a preparation method thereof, and belongs to the technical field of lithium ion batteries. The preparation method comprises the following steps: coating graphene oxide and lithium iron phosphate by adopting spray drying or evaporation drying to prepare a graphene-coated lithium iron phosphate solid, and carrying out heat treatment on the obtained graphene-coated lithium iron phosphate solid to prepare a graphene-coated lithium iron phosphate composite material, wherein the ratio of the sheet diameter of the graphene oxide to the D50 of the lithium iron phosphate is 0.05-40. According to the preparation method, the specific surface area of the obtained graphene-coated lithium iron phosphate composite material is effectively controlled by controlling the matching of the sheet diameter of graphene oxide and the particle size of lithium iron phosphate, and the processability of the coated material is greatly improved. Meanwhile, the resistivity of the prepared graphene-coated lithium iron phosphate composite material is reduced, and the charge-discharge performance of the material under high multiplying power can be improved.
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Description

technical field

[0001] The invention belongs to the technical field of lithium ion batteries, and relates to a graphene-coated lithium iron phosphate composite material and a preparation method thereof. Background technique

[0002] The olivine-type lithium iron phosphate belongs to the orthorhombic crystal system, because Li + The one-dimensional diffusion mechanism and PO 4 The hindering effect of the tetrahedron, resulting in Li + In its diffusion rate and electronic conductivity are extremely low. This intrinsic defect greatly limits its application in the high-magnification and low-temperature markets. Therefore, effectively overcoming these two obstacles will greatly promote the electrochemical performance of LFP.

[0003] Carbon coating and particle nanosizing are currently the most widely used and convenient modification methods in the industry. Good carbon coating can provide an effective electronically conductive network for electrode materials; particle nanos...

Claims

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