The Electrochemistry of Amorphous Si-B Thin Film Electrodes in Li Cells

Abstract

Abstract Si1-xBx thin films of 0.071 ≤ x ≤ 0.950 have been synthesized using combinational sputtering. All Si1-xBx film compositions had a highly amorphous structure consisting of amorphous Si and B phases, as characterized by X-ray diffraction. In Li cells, it was found that all of the Si is active and the B is inactive with lithium. Otherwise, the Si1-xBx films have similar characteristics as pure Si film electrodes in Li cells, except with reduced capacity due to the added B. However, shifts in the voltage curves appear when the B content is increased that may be induced by stress-voltage coupling between the active Si and the inactive B phases.