Preparation method for core-shell type carbon-coated iron nitride nano-composite particles and application of core-shell type carbon-coated iron nitride nano-composite particles

Abstract

The invention discloses a preparation method for core-shell type carbon-coated iron nitride nano-composite particles and the application of the core-shell type carbon-coated iron nitride nano-composite particles, and belongs to the field of nano-material preparation technologies and application. The method is characterized by comprising the following steps of: automatically controlling direct current arc hydrogen plasma equipment to evaporate bulk iron raw materials, and simultaneously introducing methane and argon according to a certain proportion to obtain carbon-coated iron nano-particle precursors; and performing nitriding thermal treatment on the precursors in the ammonia atmosphere of 400 DEG C for 3 to 4 hours to obtain the carbon-coated iron nitride nano-composite particles. A lithium ion battery cathode prepared from the carbon-coated iron nitride nano-composite particles which serve as active substances has the first reversible specific capacity of 550mAh / g and high cycle stability. The method and the application have the advantages that: the carbon-coated iron nitride nano-composite particles prepared by the low-temperature nitriding of the in-situ synthesized carbon-coated iron nano-particle precursors have high lithium intercalation / de-intercalation capacity density and cycle stability; the raw materials are low in cost; a process is simple; the carbon-coated iron nitride nano-composite particles can be prepared in large scale; and industrial production requirements are met.

Description

technical field [0001] The invention belongs to the field of nanometer material preparation technology and application. It is a preparation process of core-shell carbon-coated iron nitride nanocomposite particles, and its application as a negative electrode material for lithium-ion batteries. In particular, carbon-coated iron nanoparticles synthesized in situ are used as precursors, and carbon-coated iron nitride nanocomposite particles are obtained through a low-temperature controlled nitriding process, which improves the intercalation / delithiation capacity and cycle stability. Background technique [0002] Lithium-ion batteries (also known as lithium-ion secondary batteries or lithium-ion batteries) have the advantages of high voltage, small size, light weight, high energy density, 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. Commercial lithium-ion battery anode mat...

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Problems solved by technology

In this method, one or more metal-organic compounds (Ti(OC 2 h 5 ) 4 and VO(OC 2 h 5 ) 3 ) was dissolved in absolute ethanol, and then added mesoporous carbon nitride for decompression treatment, after suction filtration and drying, the carbon composite titanium vanadium nitride material obtained by heat treatment under the protection of nitrogen, the material obtained by this method was irreversible for the first time The capacity is very high, the material preparation cycle is relatively long, and carbon and nitride are only ordinary composites, without forming a core-shell carbon coating structure, which cannot reflect the advantages of carbon materials in cycle performance

[0005] Usually for pure Fe 3 As far as N materials are concerned, although they have a high lithium storage capacity, in the process of charging and discharging as a lithium-ion battery, the repeated deintercalation of lithium tends to make the electrode volume expand and gradually pulverize and fail, which makes the cycle performance of the electrode worse.

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