Amorphous silicon anode for lithium-ion rechargeable batteries

Amorphous silicon is investigated as a negative electrode (anode) material for lithium-ion batteries. A thin (500 Å) film of amorphous silicon is cycled versus a lithium electrode. A maximum discharge capacity of 4 Ah g−1 is observed by cycling over a voltage window of 0–3 V, but capacity fading is rapid after 20 cycles. This capacity fading can be overcome, to more than 400 cycles, by changing the lower voltage limit to 0.2 V. In this situation, the discharge capacity is about 400 mAh g−1.