Method for preparing micro-expansion graphite material by mixture of scale graphite and microcrystal graphite

Abstract

The invention discloses a method for preparing a micro-expansion graphite material by a mixture of scale graphite and microcrystal graphite. Microcrystal graphite and scale graphite are taken as the raw materials to be subjected to ball milling; next, the ball milled mixture is put into a muffle furnace to be calcined and activated in an inert atmosphere; next, the activated mixed material is subjected to chemical intercalation treatment to obtain expandable mixed graphite; and the expandable mixed graphite is put into a graphite expansion furnace to be expanded at a temperature of 400-500 DEGC to obtain the micro-expansion graphite. The micro-expansion graphite prepared in the invention is of a structure with flocculent microcrystal graphite clamped between the scale graphite sheet layers, so that inter-electron conduction can be better facilitated, and the material is more suitable for being used as the lithium ion electrode material; and the charging and discharging capacity of theformed and expanded micro-expansion graphite material is improved and the cycle performance and rate discharging performance are improved.

Description

technical field [0001] The invention belongs to the technical field of material preparation, and more specifically relates to a method for preparing micro-expanded graphite material by mixing flake graphite and microcrystalline graphite. 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] Micro-expanded graphite, as a kind of extremely low-cost graphite intercalation compound (GIC), is considered to be It is a class of anode materials with great potential that can be applied to lithium-ion batteries on a large scale. [0004] At th...

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Problems solved by technology

[0004] At the same time, the raw materials used in the current technology of using natural graphite as raw material to prepare micro-expanded graphite materials are generally crystalline large flake graphite. Although flake graphite has good collective orientation, it needs poor orientation and good uniformity in the application of battery materials. Microcrystalline graphite particles are fine, the aggregates have poor orientation and good homogeneity, and microcrystalline graphite can replace flake graphite as a raw material for preparing expanded graphite with better electrical properties, charging efficiency, battery stability and cycle performance. Greatly improved, but the capacitance is reduced, and the expansion effect of microcrystalline graphite is not good at the same time, which hinders the application of expanded microcrystalline graphite as a negative electrode material for lithium ion electrodes

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