Graphite, silicon and lithium metal anodes
Where the next big energy-density gains are coming from.
You'll learn
- Explain graphite, silicon and lithium metal anodes at engineering level
- Read the numbers that define the behaviour
- Apply the idea to a real pack
Overview
The cathode gets the headlines, but the anode is where the current generation of improvements is happening — mostly by adding silicon.
In depth
Why silicon is hard
Silicon stores roughly ten times more lithium per gram than graphite, but it swells by up to 300% when it does. That swelling cracks particles and tears the protective SEI layer, consuming lithium and electrolyte on every cycle.
| Anode | Specific capacity | Swelling | Status |
|---|---|---|---|
| Graphite | 372 mAh/g | ~10% | Mainstream |
| Silicon-graphite blend | 450–650 mAh/g | 20–40% | In production |
| Silicon-dominant | 1,500+ mAh/g | 100–300% | Early production |
| Lithium metal | 3,860 mAh/g | n/a (plating) | Development |
Activity
Anode vocabulary
1/3
Key takeaways
Remember this
- Graphite is the reliable default; silicon adds energy at the cost of swelling.
- The SEI layer is both essential and a source of ageing.
- Lithium metal anodes need solid electrolytes to be practical.
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