TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The second porous region is in direct contact with the anode major surface. The cell further comprises an external case or enclosure having at least one sidewall permeable to air or molecular oxygen-containing gas for harnessing molecular oxygen which is ultimately electro-reduced on the surface of the electron transfer medium during cell discharge. The first porous region is positioned in the cell nearby to the molecular oxygen-permeable sidewall, and is in contiguous gas phase communication with the ambient air or molecular oxygen-containing gas. The first and second porous regions are discrete porous body layers. The difference between the porous structures of the first and second regions is at least one of pore composition, pore size distribution, and solid material from which the porous region is composed. The difference in porous structure is at least based on a difference in pore size distribution. The difference in pore size distribution is tailored to cause, via capillary forces, the liquid electrolyte to preferentially fill all the pores in the second porous region and only a portion of the pores in the first porous region, where the liquid electrolyte completely fills the second region total pore volume and only partially fills the first region total pore volume, with the remaining first region pore volume filled with air or molecular oxygen-containing gas. The second region pore size distribution is defined by micropores and/or mesopores, and the first region pore size distribution is defined by a combination of macropores and mesopores. The mesopores in the second region are smaller than the mesopores in the first region. In the metal oxygen battery cell all the pores in the second region have pore radii smaller than the pore radii of the smallest pores in the first region. The amount of liquid electrolyte in the architecture is greater than the cumulative pore volume of all the mesopores in the first region and all the micropores and mesopores in the second region, but is insufficient to fill the entire architecture so that the largest pores in the first region are gas filled. The second region pore size distribution is defined by micropores and/or mesopores, and the first region pore size distribution is defined solely by macropores. The first region comprises pores of relatively large and small pore radii and the majority of the second region pore volume is defined by pores of relatively intermediate size, where the radii of the intermediate sized pores is between those of the large and small pores in the first region. The pore size distribution of the first porous region is multimodal, having at least a primary and a secondary modalities, and the pore size distribution of the second region is unimodal. The first and second regions are defined by discrete solid porous body layers, where a first solid porous body layer serves as the electron transfer region and a second solid porous body layer serves as a passive region. Preferred Method: The intermediate pores of the second region and the small pores of the first region are completely filled with the liquid electrolyte and only a portion, if any, of the large pores of the first region are filled with the liquid electrolyte, and the remaining large pores are gas filled, thus providing fast oxygen diffusion channels into the depth of the architecture.