Method for manufacturing porous silicon from steel slag, porous silicon manufactured by said method, and lithium-ion batteries using the same

Method for Manufacturing Porous Silicon via Acid Leaching of Steel Slag and Magnesium Thermal Reduction

This technology involves acid leaching of steel slag, a byproduct of steel manufacturing, to form porous silicon oxide, followed by magnesium (Mg) thermal reduction in the presence of a heat absorber (such as NaCl) to produce porous silicon with controlled nanostructures.

Conventional silicon anode materials suffer from structural collapse due to volume expansion during charging and discharging. Furthermore, synthesizing nanostructured silicon has historically been cost-ineffective due to the need for expensive raw materials (like silane), complex multi-step processes, and costly templates.

By leaching steel slag with a 1–5M acid solution to remove impurities and mixing it with a heat absorber (1.5–10 times the mass) to prevent nanostructure collapse caused by localized heat during the Mg thermal reduction process, this technology enhances the value-added potential of resource recycling and circular economy applications.

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Key Features:

• Acid leaching step: Preparing steel slag and leaching it in an acid solution 10 to 50 times the mass of the slag at 20 to 80°C.
• Heating step: Heating the acid-leached steel slag to produce porous silicon oxide.
• Thermal reduction step: Processing the porous silicon oxide using magnesium thermal reduction in the presence of a heat absorber.
• Configuration for manufacturing nanostructured porous silicon by recycling steel slag, a byproduct of steel production.

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