Preparation method of graphitized carbon negative electrode material

Abstract

The invention provides a preparation method of a graphitized carbon negative electrode material. The preparation method comprises the following steps: 1) calcining fatty acid in a nitrogen atmosphere at the temperature of 600-800 DEG C for 6-8h and cooling, so as to obtain amorphous carbon; 2) calcining the amorphous carbon in a nitrogen atmosphere at the temperature of 2,500-2,800 DEG C for 4-6h and cooling, so as to obtain graphitized carbon; 3) dispersing the graphitized carbon and a certain amount of nitrogenous polymers into anhydrous ethanol, uniformly mixing the mixture, atomizing to form balls and collecting precursors with a cyclone separator; 4) carbonizing the precursors in a nitrogen atmosphere at the temperature of 800-1,000 DEG C for 2-4h and cooling, so as to obtain porous graphitized carbon; 5) dispersing the porous graphitized carbon and a certain amount of sucrose into deionized water, uniformly mixing the mixture and performing air blast drying on the mixture at the temperature of 120-150 DEG C; carbonizing the mixture in a nitrogen atmosphere at the temperature of 800-1,000 DEG C for 2-3h and cooling, so as to obtain N-doped carbon-coated porous graphitized carbon.

Description

[0001] 【Technical field】 [0002] The invention relates to the technical field of lithium ion batteries, in particular to a method for preparing a graphitized carbon negative electrode material. [0003] 【Background technique】 [0004] Carbon / graphite materials have high theoretical specific energy, are cheap and easy to obtain, and have mature preparation processes, so they are widely used as anode materials for lithium-ion batteries. However, the carbon / graphite negative electrode has the following defects: (1) The first charge will form a solid electrolyte film (SEI) on the surface of the carbon particles, resulting in a loss of battery capacity, and the amount of SEI film formation increases with the increase in the number of charge-discharge cycles, while the internal impedance of the battery (2) During high-rate fast charging, lithium coatings are easily formed on the surface of carbon particles, and even lithium dendrites are formed to cause battery safety problems, and ...

AI Technical Summary

Problems solved by technology

However, the carbon / graphite negative electrode has the following defects: (1) The first charge will form a solid electrolyte film (SEI) on the surface of the carbon particles, resulting in a loss of battery capacity, and the amount of SEI film formation increases with the increase in the number of charge-discharge cycles, while the internal impedance of the battery (2) During high-rate fast charging, lithium coatings are easily formed on the surface of carbon particles, and even lithium dendrites are formed to cause battery safety problems, and due to the presence of SEI films on the surface of carbon particles, the The high resistance to electron movement and lithium ion diffusion causes the temperature of the battery to rise too fast, and it is easy to approach or exceed the melting temperature of the battery separator, resulting in poor operation, and the performance of resistance to extreme temperatures and abuse needs to be improved; (3) The actual use of lithium-ion batteries is not Constant temperature process, after repeated charge and discharge cycles under variable temperature conditions, the expansion or contraction of the host electrode structure caused by the insertion or deintercalation of guest lithium ions will gradually damage the electrode structure, which has a great impact on the long-term cycle stability and life of the battery

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