A kind of 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: (1) placing the black phosphorus in a cell crusher for ultrasonic peeling; (2) adding the black phosphorus to the mixed solution after step (1) The carbon material is transferred into a reactor for solvothermal reaction, and after the reaction is completed, the reaction product is dried and sieved to obtain carbon-coated black phosphorus powder; (3) the carbon-coated black phosphorus powder obtained in step (2) is mixed with artificial The graphite is mixed and stirred in an organic solvent, and at the same time, ultrasonically dispersed, dried, iron-removed, and screened to obtain a black phosphorus-based graphite composite lithium ion battery negative electrode material. The black phosphorus-based graphite composite lithium ion battery negative electrode material prepared by the invention solves the disadvantages of poor material cycle life, reduces irreversible capacity, and increases charging and discharging efficiency.

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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