Various embodiments of the present invention are direct to nanoscale, reconfigurable, two-terminal memristor devices. In one aspect, a device (400) includes an active region (402) for controlling the flow of charge carriers between a first electrode (104) and a second electrode (106). The active region is disposed between the first electrode and the second electrode and includes a storage material. Excess mobile oxygen ions formed within the active region are stored in the storage material by applying a first voltage.