SOLID OXIDE MEMBRANE PROCESS FOR SOLAR GRADE SILICON PRODUCTION DIRECTLY FROM SILICON DIOXIDE

Solar grade silicon (SoG-Si), at a small fraction of its current cost, can be produced by employing the Solid Oxide Membrane (SOM) electrolysis process. The SOM electrolyzer consists of a cathode immersed in a molten fluoride flux with dissolved silicon dioxide (SiO2) on one side of an oxygen-ion-conducting stabilized zirconia membrane. On the other side of the membrane, a nickel yttria-stabilized zirconia coating acts as an anode. The SOM electrolyzer is operated by applying an electrical potential between the electrodes. Upon exceeding the dissociation potential of SiO2, silicon metal is deposited on the cathode and the oxygen ions from the melt are transported through the membrane and are oxidized at the anode. This investigation reports flux performance and preliminary experiments that have been undertaken towards the goal of SoG-Si production.