Cyclic utilization method for using graphite fine powder as negative pole material of lithium-ion batteries

Abstract

The invention provides a cyclic utilization method for using graphite fine powder as a negative pole material of lithium-ion batteries. The method comprises the following steps: (A) taking tailing generated from a lithium battery graphite negative pole material production process as a raw material, adding a bonding agent and a pore forming agent, kneading to granulate at certain temperature, then, rolling or pressing, and charring at high temperature; (B) over-crushing the charred material, reshaping, balling, so as to obtain spherical or elliptical graphite powder meeting the requirements on a grain diameter range, carrying out high-temperature graphitization, and meanwhile, adding the tailing, which is re-collected during crushing / balling, to the step (A) for recycling as the raw material; (C) carrying out grain size adjustment on balled powder, and filling gaps among grains. According to the method provided by the invention, the process is safe and controllable, the cyclic utilization of low-value graphite tailing is realized, and the prepared negative pole material is good in performance and shows good cycling, multiplying power charging / discharging and low-temperature properties.

Description

technical field [0001] The invention belongs to the field of energy, and relates to a method for negative electrode materials, in particular to a method of using ultrafine graphite powder produced in the production process of graphite negative electrode materials—"tailing" as raw material, which is recycled and reused as lithium A method for an anode material of an ion battery. Background technique [0002] With the development of the automobile industry, the depletion of non-renewable fossil fuels such as oil and natural gas has attracted increasing attention, and air pollution and room temperature effects have also become global problems. In order to solve energy problems and achieve low-carbon environmental protection, based on the current level of energy technology development, electric vehicle technology has gradually become the focus of global economic development. The United States, Japan, Germany, China and other countries have successively restricted the use of fuel...

AI Technical Summary

Problems solved by technology

However, the affinity between resin materials and graphite is poor, so the carbon materials obtained by pyrolysis and graphite are not firmly bonded, and the yield of carbon materials obtained by pyrolysis of resin is low, brittle, and the volatile content in the process of resin pyrolysis is high. , the specific surface area is high, the cohesive force of the resin is strong, it is easy to cause the coated particles to stick together, and the coating layer is easily damaged when crushed after heat treatment. At the same time, during the heat treatment process of the resin, there are too many small molecules in the resin , in the overflow process, it will cause too many voids on the surface of the coated material, resulting in an excessively large specific surface area of ​​the coated graphite, resulting in an excessively large initial irreversible capacity

[0006] The above problems affect the cycle efficiency, cycle stability and compressibility of graphite electrodes of resin-coated graphite materials.

However, when pitch, petroleum tar, coal tar or their mixtures are used to coat graphite, the specific surface area of ​​pitch pyrolytic carbon is smaller than that of resin pyrolytic carbon coated graphite, and the affinity with graphite is better, and the structure is firmer. During the heating process, it will be deformed due to melting. If the amount is too much, it will easily cause the mutual bonding of the coated graphite particles. If the amount is too small, it will easily cause uneven coating, and it will easily expand during the heating process, which will affect the electrical properties of graphite.

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