NOVELTY - A passive potassium-air battery has an insulating cover sheet and stainless steel housing having negative electrode, partitioning membrane (I), an electrolyte, partitioning membrane (II), and positive electrode. The catalytic composite positive electrode is obtained by mixing manganese dioxide, isopropyl alcohol and water, forming slurry, spraying manganese dioxide slurry to foil web surface, vacuum-drying, and carrying out carbon paper pressing. Electrolyte contains potassium bis(trifluoromethylsulfonylimide) as solute and 1-ethyl-3-butyl-hexafluorophosphate ionic liquid as solvent.    USE - Passive potassium-air battery (claimed).    ADVANTAGE - The passive potassium-air battery has simple structure, excellent cycle performance and high energy density, and suppressed negative electrode corrosion and pore clogging.    DETAILED DESCRIPTION - A passive potassium-air battery has a stainless steel housing and an insulating cover sheet formed on the upper surface of the stainless steel housing. The stainless steel housing has a negative electrode, partitioning membrane (I), an electrolyte, a partitioning membrane (II), and a positive electrode. The negative electrode is hydrophobic foam potassium negative electrode. High-purity graphite having particle size of 100 nm to 1 mu m, is dispersed in deionized water, to obtain 10-20% colloidal solution of conductive paste. Polyurethane foam is ultrasonically dispersed to obtained conductive paste at room temperature for 120-180 minutes, and power of 600-800 W is supplied. The resultant material is placed in a vacuum oven, dried at 50-70 degrees C for 30 minutes, placed in a muffle furnace, and cured at 110-130 degrees C for 3-5 hours to obtain conductive plastic-polyurethane foam material. 100-300 g/L Potassium sulfate, 10-50 g/L potassium chloride and 20-30 g/L boric acid are dissolved in deionized water in electrodeposition bath, and pH is adjusted to 4.5-5. The obtained conductive plastic-polyurethane foam material is placed in electrodeposition bath, and current of 200 mA to 2 A, is supplied for 30-60 minutes at 50-70 degrees C. The resultant material is oxidized in a tube furnace at 50-55 degrees C for 60-120 minutes, and hydrogen is supplied and reduction sintering is carried out at 45-50 degrees C for 30-60 minutes to obtain potassium foam material. The obtained potassium foam material is immersed in 4-6 %mass polytetrafluoroethylene emulsion at room temperature for 30-60 minutes, and vacuum-dried at 40-50 degrees C for 3-5 hours, to obtain hydrophobic foam potassium negative electrode. The catalytic composite positive electrode is obtained by mixing manganese dioxide, isopropyl alcohol and water, forming slurry containing manganese dioxide and isopropyl alcohol ratio of 1:18-1:20, spraying manganese dioxide slurry to foil web surface, vacuum-drying at 120-135 degrees C for 60-120 minutes, and carrying out carbon paper pressing. Electrolyte contains potassium bis(trifluoromethylsulfonylimide) as solute and 1-ethyl-3-butyl-hexafluorophosphate ionic liquid as solvent, in the ratio of 1:8-1:10.