A high capacity adsorbent may be used for enriching oxygen concentration in an air stream. Such a high capacity adsorbent may be from about 2 to about 3 times lighter relative to the currently available technology. Furthermore, the high capacity adsorbent is readily capable of regeneration after deactivation by water vapor. Unlike current available immobilization technology in which clay binder was used to bind 13X zeolite and additional 10% organic binder was used to immobilize beads, the adsorbents of the present invention may be made using just an organic binder, thereby reducing pore spoilage caused by the clay binder. Further unlike conventional adsorbents, which may use sodium as its cation, the adsorbent of the present invention uses a lithium cation, thereby resulting in enhanced nitrogen adsorption performance.