Silicon Oxide-Based Composite Anode Active Material for Lithium Secondary Batteries and Manufacturing Method Thereof

High-Efficiency SiOx Anode Material Formed with Homogeneous Magnesium Silicate Using Alkali Halide Additives

This technology is a silicon oxide composite anode active material that suppresses magnesium gas leakage by adding alkali metal halide compounds during the reaction between silicon oxide and magnesium hydride. It forms homogeneous magnesium silicate and minimizes the content of magnesium oxide (MgO), an electrochemical insulator, through a washing process.

Conventional manufacturing processes for magnesium-silicon oxide composites have faced issues with low reaction homogeneity due to the evaporation or leakage of magnesium gas. Additionally, the generated magnesium oxide acts as an insulator, limiting electrochemical performance and initial efficiency.

This technology uses an alkali metal halide compound (MX) as a reaction additive to prevent magnesium gas leakage and includes a washing step with distilled water or an acidic aqueous solution after heat treatment to reduce residual MgO. The surface is coated with carbon material to enhance electrochemical stability. Applicable to silicon-mixed anodes for smartphones and electric vehicles, it secures higher capacity than graphite while reducing initial cycle coulombic efficiency loss.

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Key Features:

• Anode active material containing magnesium silicate represented by MgxSiOy, crystalline silicon, and 0.05 to 1 wt% of alkali metal elements
• Silicon oxide-based composite where the Mg2SiO4 peak is detected as larger than the MgO peak in X-ray diffraction patterns
• Step of preparing a mixed powder by mixing silicon monoxide, magnesium hydride, and an alkali metal halide compound
• Step of washing the heat-treated mixed powder with distilled water or an acidic aqueous solution, followed by filtration and drying

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