Preparation method for shell-core type carbon-coated metal sulfide nano-composite particles and application of particles

Abstract

The invention provides a preparation method for shell-core type carbon-coated metal sulfide nano-composite particles. The obtained composite particles as a lithium ion battery negative electrode material are applied to the field of lithium ion batteries. The method comprises the steps: adding a certain proportion of carbon source-containing substances and inert gases into an automatic control direct-current arc metal nano-powder production device, and evaporating a metal raw material to obtain a carbon-coated metal nanoparticle precursor; and then mixing the precursor with sulfur powder, putting a mixture into a high-pressure sealed reaction kettle to perform heat treatment to obtain carbon-coated metal sulfide nano-composite particles, and making a lithium ion electrode plate by taking a carbon-coated iron sulfide nano-composite material as an active substance. The method has the advantages that low-temperature sulfuration is performed by taking in-situ synthesized carbon-coated iron and tin nanoparticles as precursors to obtain carbon-coated iron sulfide and tin sulfide nano-composite particles; the lithium insertion / extraction capacity density and the cycle stability are relatively high; the raw material cost is low; a process is simple; the large-scale preparation can be realized; and the industrial production requirements are met.

Description

technical field [0001] The invention belongs to the field of nanomaterial preparation technology and application, and relates to a method for preparing a core-shell type carbon-coated metal sulfide nanocomposite particle. The nanocomposite particle is used as a lithium ion battery negative electrode material in the field of lithium ion batteries. 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. Althoug...

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Problems solved by technology

In this method, one or more metal salts (ammonium heptamolybdate and ferric nitrate, etc.) are dissolved in a mixed solution of water and ethanol, and an inert nanowire template and a sulfur-containing salt or sulfur are added and then put into a reaction kettle. After heating, cooling, centrifuging, washing, and drying, the carbon composite metal sulfide material obtained by heat treatment under nitrogen protection, although the material obtained by this method has high cycle stability, but the material preparation cycle is longer and energy consumption is greater , the preparation process is more complex and still needs to be further improved

[0005] Usually for pure FeS 2 In terms of materials, although it has a high lithium storage capacity, as a negative electrode active material, during the charge-discharge cycle of lithium-ion batteries, the repeated deintercalation of lithium will easily cause the volume expansion of the electrode to gradually pulverize and fail, and the electrochemical performance of the electrode will be reduced. Deterioration, reduced capacity

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