Figure 3

(a) Charge/discharge curves of Li21Si5(0.2–2 μm) measured at 50 mA g−1. (b) The change of delithiation (open symbol) and lithiation (solid symbol) capacities of Li-Si samples (at 50 mA g−1) and reference Si (10 mA g−1), together with coulombic efficiencies (small solid symbol). Capacity is based on the mass of an active material (Li21Si5 or Si) included in a working electrode.