Preparation method of black phosphorus-based graphite composite lithium ion battery negative electrode material

Abstract

The invention discloses a preparation method of a black phosphorus-based graphite composite lithium ion battery negative electrode material. The preparation method comprises the following steps: (1) putting black phosphorus into a cell crusher for ultrasonic stripping; (2) adding a carbon material into the mixed solution obtained in the step (1), transferring into a reaction kettle, carrying out solvothermal reaction, and drying and sieving a reaction product after the reaction is completed, so as to obtain carbon-coated black phosphorus powder; and (3) mixing and stirring the carbon-coated black phosphorus powder obtained in the step (2) and artificial graphite in an organic solvent, and simultaneously performing ultrasonic dispersion, drying, iron removal and screening to obtain the black phosphorus-based graphite composite lithium ion battery negative electrode material. According to the black phosphorus-based graphite composite lithium ion battery negative electrode material prepared by the invention, the defect of short cycle life of the material is overcome, the irreversible capacity is reduced, and the charge-discharge efficiency is improved.

Description

technical field [0001] The invention belongs to the field of lithium-ion battery materials, and in particular relates to a preparation method of a black phosphorus-based graphite composite lithium-ion battery negative electrode material. Background technique [0002] Lithium-ion batteries are a clean and renewable resource. Compared with traditional lead-acid, nickel-hydrogen, and nickel-cadmium batteries, lithium-ion batteries have the advantages of environmental friendliness, high energy density, and long cycle life. With the development of power vehicles, the requirements for the energy density of lithium-ion batteries are also getting higher and higher. The Ministry of Industry and Information Technology of the People's Republic of China requires that the energy density of lithium-ion batteries in my country will reach 300wH / kg by 2020. However, traditional graphite materials are difficult to achieve this goal as anode materials for lithium-ion batteries. The theoretica...

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Problems solved by technology

However, the pure black phosphorus material itself also has defects. For example, it will produce up to 200% volume expansion during charging and discharging, resulting in a particularly poor cycle life, and at the same time, the charging and discharging efficiency is too low. These also limit the use of black phosphorus in lithium-ion batteries. The technical bottleneck of medium batch

In theory, combining black phosphorus with other materials can improve the performance of the battery to a certain extent, but the traditional technology uses ball milling to combine black phosphorus with other materials, and the composite structure formed is unstable. During the charging and discharging process, the black phosphorus The expansion of phosphorus materials leads to the destruction of its surface structure and the shedding of coating materials, which leads to unstable electrical conductivity and poor cycle performance.

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