TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Cell: The pump comprises a deformable diaphragm and a switch to control the deformation of the diaphragm. The electrode for oxygen reduction comprises an active layer having a catalyst and a backing layer oriented away from the first chamber through which gas can diffuse. The electrode for evolution of molecular oxygen comprises an active layer having a catalyst and a backing layer oriented away from the second chamber through which gas can diffuse. The electrode for evolution of molecular oxygen is accessible from the interior of the second chamber. The first check valve inhibits flow from chamber 2 to chamber 1 and the second check valve inhibits flow from chamber 1 to chamber 2. The two chambers are in contact with a central current collector (122). The central current collector is a non-porous barrier between the two chambers. The pump comprises a deformable diaphragm within the first or second chamber and a control system to expand or contract the expansion chamber. The first or second chamber may comprise a passive expansion chamber. A first separator is located between the electrode for reduction of molecular oxygen and the interior of the first chamber. A second separator is located between the electrode for evolution of molecular oxygen and the interior of the second chamber.Preferred Parameter: The fuel cell has a self-contained volume of less than 1 L.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The fuel cell composition comprises an elemental metal of zinc, or oxidized zinc. The backing layer of the electrode for oxygen reduction includes carbon particles. The active layer of the electrode for evolution is free of amorphous carbon particles. It has an electrical conductor comprising graphitic carbon, powdered elemental metal, or a conductive metal composition. The central current collector comprises an elemental metal.    TECHNOLOGY FOCUS - METALLURGY - Preferred Component: The elemental metal of the fuel cell composition can be zinc alloy. The central current collector may comprise metal alloy.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The fuel cell composition comprises an aqueous base.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The fuel cell composition comprises an elemental metal of zinc, or oxidized zinc. The backing layer of the electrode for oxygen reduction includes carbon particles. The active layer of the electrode for evolution is free of amorphous carbon particles. It has an electrical conductor comprising graphitic carbon, powdered elemental metal, or a conductive metal composition. The central current collector comprises an elemental metal.    TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The active layer of the electrode for oxygen reduction includes an ion conducting polymer within a polymer matrix. The fuel cell composition includes a viscosity modifying agent of cellulose derivative. The two separators (116, 118) comprise a porous polymer.