Lithium iron phosphate-based composite positive electrode material as well as preparation method and application thereof

Abstract

The invention discloses a lithium iron phosphate-based composite positive electrode material. The lithium iron phosphate-based positive electrode material comprises lithium iron phosphate and graphene, wherein a thin film made of the grapheme uniformly wraps a lithium iron phosphate nanocrystal, the lithium iron phosphate is obtained by converting a lithium iron phosphate precursor, and the lithium iron phosphate precursor and the graphene are simultaneously synthesized through one-time reaction. The preparation method of the composite positive electrode material comprises the following steps: mixing a lithium source, an iron source and phosphate according to a stoichiometric ratio, adding nanoscale flake graphite and the like, carrying out high-energy ball milling so as to obtain the precursor, heating the obtained precursor in an inoxidizability atmosphere, and carrying out heat preservation, thus obtaining the lithium iron phosphate-based composite positive electrode material disclosed by the invention. The lithium iron phosphate-based composite positive electrode material disclosed by the invention can be applied as the lithium battery positive electrode material. The first specific discharge capacity of the lithium battery at the 2C rate can reach above 163mAh g<-1>, and after the battery cycles 1000 times at the 2C rate, the retention rate of the specific capacity of the battery is greater than 95%.

Description

technical field [0001] The invention belongs to the field of lithium ion secondary battery materials, and in particular relates to a lithium iron phosphate lithium battery composite positive electrode material and a preparation method and application thereof. Background technique [0002] The consumption of fossil energy and environmental pollution have promoted the development and utilization of clean secondary energy. Lithium-ion batteries have attracted much attention because of their high energy density, high cycle performance and high safety performance. Lithium iron phosphate with olivine structure is considered as an ideal cathode material for electric vehicles because of its low cost, good reliability of lithium intercalation and thermal stability, etc., but its poor electronic conductivity makes its rate performance limited. limit. [0003] Graphene has good electronic conductivity, large specific surface area, good mechanical properties, and contributes to lithium...

AI Technical Summary

Problems solved by technology

Due to the complex and cumbersome process of synthesizing graphene, the process of preparing composite materials is long and inefficient

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