An apparatus for separating oxygen from a gas mixture includes an oxide layer having ion transport channels therein, which facilitate the migration of oxygen ions from a first side to a second side of the layer. Molecular oxygen is decomposed into oxygen ions at the first side, whereas oxygen ions recombine into molecular oxygen at the second side. A first chamber into which a gas mixture (e.g., air) is admitted is located on the first side of the oxide layer. A second chamber receives oxygen from the oxide layer, and is located on the second side of the oxide layer; the second chamber has a polarizable medium that is in contact with the oxide layer. A gate electrode in contact with the polarizable medium applies an electric field to the second side of the oxide layer, thereby driving oxygen ions across the oxide layer.