Preparation method of nanometer iron oxide particle/expanded microcrystalline graphite composite material used for lithium ion batteries

Abstract

The invention discloses a preparation method of a nanometer iron oxide particle / expanded microcrystalline graphite composite material used for lithium ion batteries. The preparation method comprises the following steps: taking microcrystalline graphite as a raw material, and carrying out first chemical intercalation treatment and high temperature expansion to obtain primary expanded microcrystalline graphite; then taking the primary expanded microcrystalline graphite and ferrocene as raw materials, then carrying out mixing ball-milling by taking the primary expanded microcrystalline graphite and ferrocene as raw materials, and then carrying out second expansion to obtain the nanometer iron oxide particle / expanded microcrystalline graphite composite material. A twice high temperature expansion method is creatively combined, the prepared composite material is tightly combined, nanometer iron oxide particles are uniformly dispersed on the surface of expanded microcrystalline graphite, thelithium storage capacity is relatively high, and the circulation and rate capacity are excellent.

Description

technical field [0001] The invention belongs to the technical field of material preparation, and more specifically relates to a method for preparing a nano-iron oxide particle / expanded microcrystalline graphite composite material for lithium-ion batteries. Background technique [0002] Due to the advantages of high output voltage and energy density, good cycle stability, and environmental friendliness, lithium-ion batteries have occupied most of the consumer electronics market as a power source for various electronic products. In recent years, with the The rapid replacement of products and the continuous development of the electric vehicle market require lithium-ion batteries to have lighter weight, smaller volume and higher power density. [0003] Expanded graphite, as a kind of extremely low-cost graphite intercalation compound (GIC), is considered to be a A class of highly potential carrier materials that can be applied to the negative electrode of lithium-ion batteries ...

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Problems solved by technology

[0004] Most of the current preparation of nanoparticle / expanded graphite composites involves a solution process, and the structure of expanded graphite will change significantly after the solution impregnation-drying process, which affects the performance of its carrier properties, while some reported non-solution Preparation methods such as high-energy ball milling and dry mixing can only achieve physical combination, and it is difficult to ensure the close combination and uniform distribution of nanoparticles and expanded graphite.

[0005] At the same time, the raw material used in the technology of preparing expanded graphite materials from natural graphite is generally crystalline large flake graphite. Although the collective orientation of flake graphite is good, it needs poor orientation and good uniformity in the application of battery materials. Graphite material, microcrystalline graphite particles are small, the aggregate orientation is poor, and the homogeneity is good. Microcrystalline graphite can replace flake graphite as a raw material for preparing expanded graphite with better electrical properties. Although the charging specific capacity is slightly lower, the charging efficiency and battery Stability and cycle performance can be greatly improved, but because the expansion effect of microcrystalline graphite is not good, the electrical properties of the composite material of expanded microcrystalline graphite and nanoparticles are greatly reduced. The prior art uses expanded microcrystalline graphite to prepare nanoparticles / Expanded graphite composite materials have not achieved their due excellent electrical properties. How to improve the expansion effect of microcrystalline graphite and the composite effect of expanded microcrystalline graphite and nanoparticle materials are urgent research issues.

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