Method for preparing silicon-carbon anode material for lithium ion battery

Abstract

A method for preparing a silicon-carbon anode material for a lithium ion battery belongs to the field of lithium ion batteries. The method comprises the following steps of: 1) adding SiO2 powder to anaqueous solution of sucrose for stirring and mixing, evaporating the solution to dryness, and drying the solid; 2) grinding the sucrose coated with SiO2, heating to 300-1100 degrees centigrade for sucrose cracking, and then grinding, tableting, and sintering; 3) wrapping the obtained carbon-coated SiO2 tablet with foamed nickel, attaching the fine molybdenum wire to the metal molybdenum wire as acathode, connecting the graphite rod and the stainless steel wire as an anode, and regarding the silver-silver chloride electrode as a reference electrode; 4) after heating CaCl2 to melt, inserting the cathode, the anode and the reference electrode into the molten salt, applying a voltage of 1.5 to 3.0V between the cathode and the anode, electrolyzing the constant cell pressure for 10 to 15 hours, taking the cathode after electrolysis out from the molten salt for cooling, cleaning and drying, so as to obtain a silicon-carbon anode material for a lithium ion battery. The method may be made into a silicon-carbon anode material for a lithium ion battery with excellent performance, and is environmentally friendly, low in cost and simple in operation.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a method for preparing silicon-carbon negative electrode materials for lithium ion batteries. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, long service life, and no memory effect. They have become the most widely used secondary batteries and still have broad development space. The positive and negative electrode materials of lithium-ion batteries are the key materials that determine their performance. The current commercial lithium-ion battery anode material is mesocarbon microspheres (MCMB), which are made of carbon-based material graphite, and its theoretical capacity is low (372mAh / g). The theoretical capacity of silicon is as high as 4200mAh / g, the discharge voltage is low, and the safety performance is good. These advantages make silicon expected to replace carbon as the negative electrode material of the next generatio...

AI Technical Summary

Problems solved by technology

However, silicon has a large volume effect in the process of lithium intercalation and desorption during charge and discharge, which causes it to be stripped from the conductive medium current collector, resulting in poor cycle performance and low Coulombic efficiency.

In addition, silicon itself does not have good conductivity