Anode Precursor Supply Chain — Graphitization, Carbonization and CVD Equipment
From Raw Materials to Anode Powder
Silicon-carbon anode material is not a single product but a family of composites assembled through a multi-step process chain. Each step requires specialized capital equipment, most of which is designed, built, and operated in China. Understanding the equipment bottlenecks explains why anode capacity takes 18–24 months to add and why China controls over 90% of global production.
The process chain runs: metallurgical silicon → nano-Si or SiOx precursor → carbon precursor (pitch or polymer) → mixing and granulation → carbonization/graphitization → CVD carbon coating → classification and surface treatment → finished anode powder.
Key Equipment Categories
| Equipment | Function | Leading suppliers | Capex intensity |
|---|---|---|---|
| Graphitization furnace (Acheson / LWG) | Convert carbon precursor to graphite structure, 2,800–3,000 °C | Fangda Carbon, local OEMs | High |
| Rotary carbonization furnace | Pyrolyze organic precursor to hard or soft carbon, 600–1,200 °C | Domestic OEMs (Guangdong, Hunan) | Medium |
| CVD reactor (fluidized bed or rotary) | Deposit carbon coating from CH₄/C₂H₂ on Si-containing core | Developed in-house by producers | Medium–High |
| Jet mill / air classifier | Achieve D50 5–10 µm with tight PSD | Alpine, local OEMs | Medium |
| Carbon coating drum | Surface oxidation passivation after CVD | Standard equipment | Low |
China Regional Concentration
Guangdong (especially Shenzhen and Dongguan), Hunan (Chenzhou, Changsha), and Zhejiang (Lanxi, Jinhua) are the three main production clusters. Guangdong leads in finished anode output (BTR, Shanshan large facilities). Hunan has strong graphitization and carbonization capacity. Zhejiang, anchored by Lanxi Zhide (兰溪致德新能源材料), is emerging as the CVD silicon-carbon specialty hub — benefiting from local silicon metal supply chains and lower power costs than Guangdong.
Power cost is the dominant operating variable: graphitization at 3,000 °C is energy-intensive, and CVD carbon coating requires sustained high temperatures. Producers in hydropower-rich regions (Sichuan, Yunnan, and parts of Zhejiang) have structural cost advantages.
Supply Chain Risk Points
Silane gas (SiH₄) for CVD is a single-source vulnerability for many producers who purchase from external gas companies. Lanxi Zhide's self-produced SiH₄ eliminates this dependency. Graphitization furnace lead times of 12–18 months create capacity addition lags. Pitch precursor quality (softening point, QI content) directly impacts final anode carbon layer structure.