A kind of graphite negative electrode material and preparation method thereof

Abstract

The invention discloses a graphite cathode material and a preparation method thereof and belongs to the field of batteries. The preparation method includes: combining one or more of petroleum coke, asphalt coke and resistance materials into a raw material, adding a graphitization catalyst, graphene and binder into the raw material, and mixing and kneading; performing rolling treatment on the material obtained after the mixing and kneading, performing primary crushing on the rolled material, and performing compression; performing primary calcining on the compressed material; impregnating molten asphalt into the material after the primary calcining, and performing secondary calcining; performing secondary crushing on the calcined material, and performing shaping and balling; performing graphitization treatment on the material after the shaping and balling. The graphite cathode material is good in liquid absorption performance, low in expansion after battery charging, good in cycle performance, high in gram capacity and low in production cost.

Description

technical field [0001] The invention relates to the field of batteries, in particular to a graphite negative electrode material and a preparation method thereof. Background technique [0002] At present, graphite is mainly used as the raw material for lithium-ion battery anode materials, which are divided into three categories: artificial graphite, natural graphite and the combination of the two. The main production processes of natural graphite anode materials are natural graphite spheroidization, natural graphite chemical purification or high-temperature purification, and natural graphite surface coating modification. Conventional primary particle artificial graphite anode materials generally use petroleum coke, pitch coke, needle coke calcined coke as raw materials, and are produced by crushing, graphitization, mixing and screening processes. Secondary granular lithium-ion battery anode materials generally use petroleum coke and needle coke raw coke as raw materials, cru...

AI Technical Summary

Problems solved by technology

The production process of mesocarbon microspheres is complicated, the environment pressure is high, and the production cost is high

[0003] Although the natural graphite negative electrode material has a high gram capacity and a high compaction density, the natural graphite negative electrode material has poor liquid absorption performance, large expansion of the negative electrode material after the battery is charged, and poor cycle performance.

These shortcomings lead to the fact that natural graphite anode materials can only be used in the production of conventional 3C lithium-ion batteries, and are not suitable for the production of soft packs and high-voltage polymer lithium-ion batteries, let alone the production of power lithium-ion batteries.

[0004] Conventional primary particle artificial graphite anode materials have low gram capacity, low compaction density, and poor liquid absorption performance, but the cycle performance is better than natural graphite. It is suitable for the production of low-end 3C and power lithium-ion batteries. Not suitable for the production of high-voltage polymer lithium-ion batteries, and cannot meet the needs of high-end lithium-ion batteries

[0005] Secondary granular lithium-ion battery anode materials have the characteristics of high gram capacity, high compaction density, good liquid absorption performance, and low expansion coefficient. They are currently widely used in the production of high-end 3C lithium-ion batteries and power lithium-ion batteries. The current cost of this type of negative electrode material is relatively high, and the production process is relatively complicated. If the process of this type of negative electrode material is not handled properly, the secondary particles will easily break into primary particles during the charging and discharging process of the battery, resulting in capacity loss and a sharp decrease in cycle life.

[0006] The mesophase carbon microsphere negative electrode material has a spherical shape and the material is relatively stable, so this type of negative electrode material has excellent cycle performance and good rate performance, but its gram capacity is low, the compaction density is low, and the cost is high. The material is only used in the production of lithium-ion batteries that do not require high capacity but require high cycle and rate performance, such as the production of aircraft models, electric tools and some automotive lithium-ion batteries

Images