The lithiation/delithiation structures starting from the crystalline phases are different from those starting from the amorphous phases, especially at the initial stage. then becomes a-LixSi, as reported by Ogata et al. . Moreover, the voltage curve in Figure shows that there is also a voltage plateau during delithiation starting from c-Li3.75Si, indicating that c-Li15Si4 coexists another phase in this two-phase region. The a-Li1.84Si is the other endmember of this two-phase region as shown in Figure and. The voltage of the more stable c-Li15Si4 phase is higher than that of other amorphous phases in the Li content range of about 1.84<x<3.75, which corresponds to the contribution of the latent heat of the phase transformation.