Layered amorphous silicon as negative electrodes in lithium-ion batteries

Chemical delithiation is used to prepare bulk quantities of amorphous silicon powder from lithium-silicon compounds. The amorphous silicon materials formed are air and water stable and are found to have layered structures. When cycled in Li-ion half cells, coatings containing layered amorphous silicon are found to have significantly lower volume expansion during lithiation and improved cycling characteristics compared to that of bulk crystalline Si. We suggest chemical delithiation as a convenient method to synthesize bulk quantities of Si powders containing self-organized void spaces that can accommodate volume expansion during lithiation.