Silicon/carbon anode composite for lithium-ion batteries, manufacturing method thereof, and lithium-ion battery comprising the same

Anti-detachment anode composite featuring silicon nanoparticles coated with polymers and bonded to graphite via mechanofusion

This technology is an anode composite where silicon nanoparticle surfaces are pre-coated with a 1–5 nm layer of polymer or pitch, then physically and chemically bonded to a carbon substrate, such as graphite, using a mechanofusion process.

Silicon-based anode active materials suffer from significant volume expansion during charge and discharge cycles, leading to pulverization. This causes the material to detach from the current collector and lose contact between active particles, resulting in degraded battery performance. Furthermore, differences in surface energy between silicon and graphite have historically made uniform surface coating difficult through simple mixing.

This technology involves milling silicon particles with a polymer (such as PAN) or pitch solution to create a 1–5 nm adhesive layer on the nanoparticle surface, followed by physical and chemical bonding to the carbon substrate using mechanofusion equipment at 1,000–5,000 rpm. This prevents silicon detachment and ensures structural stability of the composite. Applicable to lithium-ion batteries for EVs and energy storage systems using graphite-silicon anodes, this technology maintains long cycle life by preventing silicon from separating from the graphite despite repeated expansion.

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Key Features:

• Carbon substrate selected from artificial graphite, natural graphite, carbon black, or graphene, onto which silicon nanoparticles are bonded
• Silicon nanoparticles with an average particle size of 10–800 nm, surface-coated with a 1–5 nm layer of polymer or pitch
• Coating polymer, such as polyacrylonitrile, used in a weight ratio of 1:0.005 to 0.3 relative to the silicon nanoparticles
• Step of performing mechanofusion at 1,000–5,000 rpm for 10–60 minutes to physically and chemically bond silicon nanoparticles to the carbon substrate surface

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This invention was developed with support from the BrainLink project for the development of tandem systems for eco-friendly carbon-free hydrogen production and large-area device demonstration, funded by the Ministry of Science and ICT.

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