TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The metal in the oxygen-reduction enhancing compound is chosen from magnesium, aluminum, manganese, gallium and zinc.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The oxygen-reduction enhancing compound comprises metal-containing additive, metal and/or water, organic molecule containing additive, protic organic molecule containing additive, and other additive. The other additive is chosen from triflic acid, benzonitrile, acetophenone, methanesulfonic acid, hydronium triflate, pyridazinium triflate, acetic acid, pyridinium triflate, 1,2-dimethyl imidazolium triflate, N,N-diethyl-N-methylammonium triflate, 2,2,2-trifluoroethanol, 2-butyl-1,1,3,3-tetramethylguanidinium triflate and water. The ionic liquid comprises aprotic ionic liquid including cation having strongly bonding proton(s), preferably triethylammonium methanesulfonate, 1-methyl-3-octylimidazolium tetrachlorogallate, diethylmethylammonium triflate, and 1-butyl-3-methylimidazolium bis(trifluoromethane)sulfonamide. The oxygen reduction half-reaction involves a transfer of at least two electrons per oxygen molecule. The air electrode comprises polytetrafluoroethylene. The fuel electrode is porous. The low-temperature ionic liquid is hydrophobic and/or aprotic, and contains room-temperature ionic liquid. The anion in the ionic liquid is chosen from tetrachloroaluminate, bis(trifluoromethylsulfonyl)imide, methylsulfonate, nitrate, and acetate. The cation in the ionic liquid is chosen from imidazolium, sulfonium, pyrrolidinium, pyridinium, triethylammonium, diethylmethylammonium, dimethylethylammonium, ethylammonium, ( alpha )-picolinium, 1,8-bis(dimethylamino)naphthalene, 2,6-di-tert-butylpyridine, quaternized ammonium and phosphonium. The fuel electrode further comprises liquid-impermeable backing which is impermeable to air. The air electrode comprises a catalyst. The catalyst is chosen from manganese oxide, nickel, pyrolyzed cobalt, porphyrin-based catalyst, activated carbon, perovskite, spinel, silver, platinum, and/or their mixtures. The air electrode is gas permeable. The ionic liquid comprises protic ionic liquid containing cation having reversible proton(s), with dissociation constant of 16 or less (preferably, 14 or less). The ratio of concentration of protic ionic liquid with respect to aprotic ionic liquid is 1:1. Preferred Property: The low-temperature ionic liquid has vapor pressure of more than its melting point to less than 1 mm mercury at 20 degrees C.