An In Situ X-Ray Diffraction Study of the Reaction of Li with Crystalline Si

The electrochemical reaction of lithium with a crystalline Si composite electrode at room temperature was investigated using in situ X-ray diffraction (XRD) techniques. The study confirmed that crystalline Si becomes amorphous during the first lithiation. The range of the coexistence region between crystalline Si and amorphous lithiated Si is . The highly lithiated amorphous phase was found to crystallize into rapidly at about (vs ) and this phase exists over a relatively narrow range of capacity. During delithiation, the phase coexists with amorphous with . Once all the phase disappears, the amorphous phase persists as the remaining Li is extracted. The formation of the phase can be avoided if the potential…

• DU
  Dalhousie University