Preparation method of carbon/graphite composite anode material

Abstract

The invention relates to a preparation method of a carbon/graphite composite anode material. The carbon/graphite composite anode material is prepared from the following raw materials with following grain sizes and weight percent: 1.5%-2.5% of carbon black, 5%-8% of natural graphite with the grain size being not greater than 1mm, 25%-30% of calcined petrol coke powder with the grain size being not greater than 0.075mm, 15%-20% of calcined petroleum coke with the grain size being 1-4mm, 10%-15% of electrically calcined anthracite with the grain size being 4-10mm, 5%-10% of electrically calcined anthracite with the grain size being 10-16mm, 5%-15% of calcined pitch coke with the grain size being 10-16mm, 18%-20% of coal pitch, and short carbon fibers, the weight of which is 1%-3% of the total weight of the aforementioned raw materials. The carbon/graphite composite material is prepared by the following steps: burdening, mixing kneading, roasting, graphitizing, crushing and balling. By combination of respective advantages of carbon materials and graphite materials as the anode materials, the prepared composite material has the characteristics of high first capacity, high first charge and discharge efficiency, electrolyte solvent resistance, isotropy and the like.

Description

Technical field [0001] The invention relates to a method for preparing a carbon / graphite composite negative electrode material, and belongs to the technical field of lithium ion batteries. Background technique [0002] Since Sony Energy Technology of Japan took the lead in successfully developing lithium-ion batteries using carbon anodes in the early 1990s, lithium-ion batteries have rapidly occupied the civilian secondary battery market at an average annual rate of 15% and have become the first choice for portable electronic devices. power supply. The rapid development of lithium-ion batteries is mainly due to the contribution of electrode materials, especially the progress of anode materials. Lithium-ion battery anode materials are required to have the following characteristics: ①The lowest possible electrode potential; ②High ion diffusivity in the solid structure of the negative electrode; ③High reversibility of deintercalation; ④Good electrical conductivity and thermodynamic...

AI Technical Summary

Problems solved by technology

The solid electrolyte membrane is formed by the interaction of electrolyte, negative electrode material and lithium ions, and irreversibly consumes lithium ions, which is a major factor in the formation of irreversible capacity; the second is that during the process of lithium ion intercalation, the electrolyte is easy to co-embed with it In the process of moving out, the electrolyte is reduced, and the gas products generated cause the graphite flakes to peel off. Especially in the electrolyte containing PC, the graphite flakes fall off to form a new interface, leading to the formation of further SEI and the increase of irreversible capacity. At the same time, the cycle Decreased stability

As anode materials for lithium-ion batteries, carbon materials still have disadvantages such as low charge-discharge capacity, large irreversible loss in the first cycle, co-intercalation of solvent molecules, and high preparation costs. These are also key issues that need to be solved in current research on lithium-ion batteries.

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