Preparation method of honeycomb structure silicon-cobalt tetraoxide composite

Abstract

The invention discloses a preparation method of a silicon-cobaltosic oxide compound with a honeycomb structure. The method comprises the following steps: preparing silicon with the particle sizes of 10-80nm and a cobalt salt solution with the concentration of 2.5-5g / L; dispersing the prepared silicon into the cobalt salt solution at the mass ratio of (1:4,000) to (1:7,000), and stirring the silicon for 5-15 hours to form a turbid liquid; carrying out heat preservation on the prepared turbid liquid in an airtight condition for 5-25 hours, carrying out hydrothermal reaction, and setting the hydrothermal reaction temperature to be 60-160 DEG G; filtering the turbid liquid after hydrothermal reaction, and collecting a dry sediment; washing the obtained sediment and then carrying out drying treatment at 60-100DEG C; and burning the dried sediment in an inert gas atmosphere, setting the burning temperature to be 300-800 DEG C and setting the burning time to be 2-12 hours, so as to prepare the silicon-cobaltosic oxide compound with the honeycomb structure.

Description

technical field [0001] The invention relates to a lithium ion battery negative electrode material, in particular to a negative electrode material based on tricobalt tetroxide and a preparation method thereof. Background technique [0002] Lithium-ion batteries are widely used in electronic products such as mobile phones and computers. In recent years, the industry is also trying to use lithium-ion batteries as the power source of electric vehicles. Lithium-ion batteries include positive electrodes, negative electrodes, electrolytes, and separators. The improvement of lithium-ion battery performance mainly depends on the performance of lithium intercalation and extraction electrode materials. In commercial applications, the technology of graphite-based carbon anode materials is relatively mature, but its specific capacity is low (theoretical specific capacity is about 372mAh / g). The existing negative electrode materials are increasingly unable to meet the requirements. [...

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Problems solved by technology

But on the other hand, the initial charge and discharge of cobalt trioxide electrode material is very irreversible, and the capacity decays severely after multiple cycles, which seriously hinders its practical application in lithium-ion batteries.

[0007] Such as Yoon Hwa, Won-Sik Kim et al. disclose a kind of silicon-cobalt tetraoxide core-shell composite material in "Physical Chemistry Journal, Series C" (The Journal ofPhysical Chemistry C, 2013,117,7013-7017), but its The preparation process is obviously different from the method of the present invention, so the composites produced are also different (mainly in the structure and morphology of the composites), specifically: no dispersant is used in the preparation method developed by Yoon Hwa et al., and the composite The content of silicon in the compound is relatively large, so what is formed is not the structure of honeycomb-shaped cobalt tetroxide coated nano-silicon, but the structure of needle / rod-shaped cobalt tetroxide growing from the surface of silicon, so the structural stability and conductivity of the composite are poor.

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