Silicon anode

A lithium-ion battery anode that uses silicon, alone or blended with graphite, to store far more lithium than graphite alone.

• The anode holds lithium while the battery is charged; silicon can store nearly ten times more per gram than graphite (about 3,600 vs 372 mAh/g).
• Silicon expands by up to about 300% as it absorbs lithium, cracking particles and consuming lithium in fresh side reactions each cycle.
• Fixes use nanoscale or porous silicon-carbon particles with room to swell; most cells today blend in only a few percent silicon.
• Higher-silicon anodes from firms like Sila and Group14 are entering phones and early EVs, promising roughly 20–40% more energy.