Preparation method and application of shell-core carbon-coated metal phosphide nanometer composite particle

Abstract

The invention provides a preparation method of a shell-core carbon-coated metal phosphide nanometer composite particle. The obtained composite particle is used as a lithium ion battery negative electrode material to be applied to the field of a lithium ion battery. The preparation method comprises the steps of adding a certain proportion of a substance containing a carbon source and inert gas into automatic control DC arc metal nanometer powder production equipment, and evaporating a metal raw material to obtain a carbon-coated metal nanometer particle precursor; mixing and placing the precursor and red phosphorus powder in a high-pressure sealing reaction kettle for thermal treatment to obtain a carbon-coated metal phosphide nanometer composite material; and fabricating a lithium ion electrode plate by taking the carbon-coated nickel phosphide nanometer composite material as an active substance. The preparation method has the advantages that the carbon-coated nickel nanometer particle synthesized in an in-situ way is used as the precursor, the carbon-coated nickel phosphide nanometer composite particle is obtained by low-temperature phosphorization, and the composite particle has relatively high intercalation / de-intercalation lithium capacity density and cycle stability, is low in raw material cost and simple in process, can be prepared on a large scale and is suitable for industrial production.

Description

technical field [0001] The invention belongs to the field of nanomaterial preparation technology and application, and relates to a preparation method of a core-shell type carbon-coated metal phosphide nanocomposite particle and its application in the field of lithium ion batteries as a lithium ion battery negative electrode material. Background technique [0002] Lithium-ion batteries (also known as lithium-ion secondary batteries or lithium-ion batteries) have the advantages of light weight, high energy density, high voltage, small size, good cycle performance, and no memory effect. They are considered to be the most promising applications in the 21st century. One of the energy sources, and is widely used in transportation, communications and renewable energy sectors. At present, graphite is widely used as the negative electrode material of commercial lithium-ion batteries due to its advantages of long cycle time, large amount of existence and low cost. Although carbon mate...

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Problems solved by technology

In this method, red phosphorus powder and metal powder are mixed in proportion and put into a ball mill tank, ball milled in a hydrogen or argon atmosphere for 10-50 hours, and the ball mill product is pre-baked at 400-1000°C for 5-30 hours in the same atmosphere, and finally Secondary roasting at 100-600°C for 5-30 hours under a hydrogen or argon atmosphere, the material obtained by this method has a long preparation cycle, high energy consumption, and a complicated preparation process, which still needs further improvement

[0005] Generally, for pure metal phosphide materials, although they have high lithium storage capacity, as negative electrode active materials, during the charge and discharge cycle of lithium ion batteries, the repeated lithium deintercalation tends to cause the electrode volume expansion to gradually pulverize and fail. The electrochemical performance of the electrode is deteriorated and the capacity is reduced

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