TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Component: The metal-gas cell further includes electrolyte disposed in the soft pocket member. The electrolyte is saturated with zinc oxide at a concentration of 20-50, preferably 35-40 g/L. The semi-permeable membrane is disposed in the sub-assembly to allow gases to flow out from the upper portion of the soft pocket through the sub-assembly. The semi-permeable membrane is permeable to gases but impermeable to liquids. The edges of the metal anode are rounded to avoid dropping metal powder (68). The metal anode comprises electrically conductive support structure (62) with a metal anode material. The support structure has lower and upper portions. The metal-gas battery further includes internal metal-gas cells sandwiched between first and second outermost metal-gas cells, eight elbow tubes respectively located at four corners of the two separators, metal-gas cells, positive battery terminal electrically connected to the two air cathodes of the first outermost zinc-air cell, and negative battery terminal electrically connected to the zinc anode of the second outermost zinc-air cell. The upper portion of the metal anode in each of the internal metal-gas cells is electrically connected to gas cathodes of an adjoining metal-gas cell through anode conductor. The metal anode is hung firmly in the soft pocket through a hook when the first and second retaining structures are in the first retaining structure position. The hook is attached to the first retaining structure. The one end of each elbow tube is located in the gap between each pair of the separator and gas cathode. The other end of each elbow tube passes through a hole (152) on each separator and hole on each wall of the soft pocket. The metal-gas cells are electrically connected in series. The two gas cathodes are electrically connected through pair of metal contacts extended upward above the top opening of the soft pocket.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Material: The electrolyte is an aqueous solution containing a compound from potassium hydroxide, sodium hydroxide, or sodium chloride.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Material: The electrolyte is an aqueous solution containing a compound from potassium hydroxide, sodium hydroxide, or sodium chloride.    TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The two groups of threads are made of plastic, alkaline-resistant material, polypropylene, or nylon. The semipermeable membrane is made of polytetrafluoroethylene (PTFE). The soft pocket is made of thermoplastic rubber or thermoplastic elastomer. It is from polypropylene, neoprene, ethylene propylene diene monomer, butyl rubber, ethylene propylene copolymer, or chlorosulfonated polyethylene.