Last updated: 2026-01
Material Identity
- Chemical name: Carbon-coated silicon monoxide
- Composite description: silicon monoxide with carbon surface coating
- Base formula: SiOx / C (x typically between 1 and 2, composition-dependent)
- CAS numbers: silicon monoxide (18820-29-6); carbon coating is non-stoichiometric
- Physical form: composite particulate powder
- What it is not: not pure silicon, not graphite, not a metallic alloy anode
Activation & Trigger Conditions
- Trigger: electrochemical lithiation and delithiation
- Energy domain: electrochemical potential and solid-state diffusion
- Absent trigger: no lithium insertion without electrochemical cycling
- Insufficient condition: poor carbon coverage leads to unstable interfaces
- Excess condition: deep lithiation can amplify volume expansion and interfacial stress
Functional Role
- Provides higher lithium storage capacity than graphite-based anodes
- Carbon layer supports electronic conductivity
- Carbon coating partially buffers silicon monoxide volume changes
- Contributes to composite anode structural integrity
Application Windows
- Compatible systems: lithium-ion battery anodes
- Loading range: formulation-dependent; typically blended with graphite or other carbons
- Processing notes: slurry dispersion, binder selection, and coating quality affect performance
Limitations & Failure Modes
- Large volume change → particle stress and cracking → capacity fade
- Unstable solid–electrolyte interphase → continuous electrolyte consumption → low initial efficiency
- Non-uniform carbon coating → uneven current distribution → localized degradation
Alternatives & Trade-offs
- Graphite: lower capacity but higher structural stability
- Pure silicon: higher theoretical capacity but more severe volume expansion
- Silicon–carbon composites: improved buffering with added formulation complexity
When to Use
- When higher energy density than graphite is required
- When partial mitigation of silicon volume expansion is acceptable
- When composite anode formulations are feasible
- When processing control can manage interfacial stability
FAQ
Is SiOx/C equivalent to pure silicon anodes?
No. Silicon monoxide and carbon coatings change lithiation behavior and reduce, but do not eliminate, expansion effects.
Does the carbon coating prevent all degradation?
No. It improves conductivity and buffering but cannot fully suppress mechanical and interfacial degradation.
Why do different grades behave differently?
Differences arise from SiOx composition, carbon type and thickness, particle size, and processing history.
Data
No generic numerical values are provided. Capacity, efficiency, and cycle behavior are grade- and formulation-specific and must be verified experimentally.
Sources
General battery materials literature on silicon monoxide and silicon–carbon composite anodes; supplier-specific technical documentation where available.