A porous SiO2 contacting electrode was prepared by winding a Mo wire around a porous SiO2 pellet. X-ray diffraction and scanning electron microscopy (SEM) results confirmed that SiO2 is reduced to Si at 1.00 and 1.20 V (vs Ca2+/Ca) in molten CaCl2 at 1123 K and that the reduction rate is faster at more negative potential. A comparison on the basis of the amount of SiO2 reduced in 5 min reveals that the reduction rate for a dense SiO2 plate is faster than that for a porous SiO2 pellet. However, reduction is greatly accelerated by mixing Si into the SiO2 as a conductive additive. At a Si content of 10 wt %, the reduction rate at 1.00 V exceeds that for the dense SiO2 plate. SEM observations show that the morphology of the Si produced changes from columnar to plate-like by combining the sides of Si columns with the addition of Si. Copyright 2005 The Electrochemical Society.