Solid-state electrochemical cells based on oxygen-ion conduction (pure ionic or mixed ionic/electronic conductors) allow, selective transport of oxygen (oxygen-ion conducting materials) in the form of ionic flux at high temperatures, Thus these systems can act as filters for molecular oxygen and can be used for both generation or removal of oxygen selectively. The usage of such devices are numerous including production of high purity oxygen for medical applications, aqua-culture and combustion processes; control of oxygen partial pressure in industrial environments; production of power and chemicals; and removal of oxygen from enclosures and gas streams. In this paper, a brief overview of the technology has been given and Various membrane materials for construction of such devices have been discussed.