Porous Silicon Structure and Secondary Battery Including the Same

Hollow Silicon Microsphere Multilayer Array Anode Fabricated via Polymer Template Electroplating

This technology creates hollow, multilayered porous silicon arrays by electroplating silicon microspheres onto a polymer template and subsequently removing the template. This structure mitigates the volumetric expansion stress that occurs during lithium charge and discharge cycles while maximizing the reaction surface area.

While silicon anode materials offer extremely high theoretical capacity, they suffer from excessive volumetric expansion—up to 4.12 times—during charge and discharge, leading to structural cracking and collapse. This results in shortened cycle life and the disruption of electron transport pathways within the electrode.

This technology involves self-assembling polymer microspheres to create a template, coating them with silicon via electroplating, and removing the polymer through heat treatment to produce a hollow, porous silicon microsphere structure. If necessary, conductivity can be enhanced by applying carbon, metal, or non-metal inorganic conductive materials via atomic layer deposition (ALD). Applicable to high-capacity silicon anodes for long-range electric vehicle cells or thin-film micro-batteries, the internal void space acts as a buffer for expansion, preventing the electrode structure from easily collapsing even after repeated charging.

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Key Features:

• A porous silicon structure used as an anode active material, comprising an array of densely packed, multilayered hollow silicon microspheres.
• Silicon microspheres that share internal void spaces through contact and possess a specific surface area ranging from 1 m²/g to 100 m²/g.
• A step of forming a multilayer spherical polymer layer by self-assembling polymer microspheres on an electrode.
• A step of coating a silicon film onto the spherical polymer layer via electroplating using the electrode as a working electrode, followed by removing the polymer through heat treatment.

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