Microcrystal graphite anode material and preparation method thereof, and lithium ion battery

Abstract

The present invention discloses a microcrystal graphite anode material and a preparation method thereof, and a lithium ion battery. The method comprises the steps of: performing pre-treatment of a microcrystal graphite raw ore to obtain a microcrystal graphite crude product; performing acid pickling and washing with water for the microcrystal graphite crude product until the PH of the rinsing solution is not less than 4 to obtain a first precursor; performing ball-milling mixing and briquetting of the first precursor and a binder and a catalyst to obtain a second precursor; in an inert atmosphere, performing pre-sintering and graphitization of the second precursor to obtain a third precursor; performing pulverization, nodularizing and classification of the third precursor to obtain a fourth precursor; performing hot mixing of the fourth precursor and a carbon source to obtain a fifth precursor; and in the inert atmosphere, performing sintering and screening for the fifth precursor to obtain a microcrystal graphite anode material. The method reduces the cost, improves the environmental friendliness, is high in operability and can perform mass production, and the obtained microcrystal graphite anode material is high in capacity, high in charge-discharge efficiency at first time and good in isotropy.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a microcrystalline graphite negative electrode material, a preparation method, and a lithium ion battery. Background technique [0002] Natural microcrystalline graphite, also known as cryptocrystalline graphite, amorphous graphite or earthy graphite, is composed of many tiny graphite crystals in structure, and has a high degree of graphitization, but has a high content of mineral impurities. Although it is used as a negative electrode material for lithium-ion batteries, it has Good cycle performance, but there are disadvantages such as low first Coulombic efficiency and low reversible capacity. Therefore, current commercial lithium-ion batteries generally use natural flake graphite or artificial graphite as negative electrode materials. Natural microcrystalline graphite has a wide range of sources, and the reserves in my country are huge. Compared with natural flak...

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Problems solved by technology

[0003] At present, although the first coulombic efficiency and reversible capacity of the microcrystalline graphite negative electrode material can be improved by modifying the microcrystalline graphite raw ore, the inventors have found that the capacity of the microcrystalline graphite negative electrode material prepared by the current method is still low. And the performance fluctuates greatly, still needs to be improved, and preparation method also needs to be improved, and in current preparation method usually needs to carry out multiple pickling purification to microcrystalline graphite raw ore, in order to obtain high carbon, neutral (the mass content of carbon is in 99 %, pH around 7) of microcrystalline graphite, the above-mentioned pickling and purification process is complex, with more procedures, greater energy consumption, and greater output of three wastes, resulting in higher production costs and poor environmental friendliness, which affects the microcrystalline Application and Development of Graphite Anode Materials

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