NOVELTY - Electrolytic cell (2) (I) comprises: a containment vessel configured to contain an electrolyte; at least one electrode (4) configured to be in fluid communication with the electrolyte and in electrical communication with a power supply for producing a first gas and a second gas via electrolysis of the electrolyte; a separator (10) configured to be in fluid communication with the electrolyte and to separate the first gas from the second gas; a first gas collection region in the containment vessel; and a second gas collection region substantially concentric with the first gas collection vessel.    USE - The electrolytic cells are useful for reversible separated production of pressurized hydrogen and oxygen.    ADVANTAGE - The electrolytic cells: tolerate impurities and products during operation; provide more efficient mass transport including rapid ion replenishment processes and deliveries to desired electrodes, thus assuring greater electrical efficiency, more rapid dissociation and greater separation efficiency along with prevention of undesirable side reactions, and increasing the rate and efficiency of ion production and delivery to electrodes which increases the efficiency and current limit per electrode area; allow off-peak electricity which is quickly and efficiently converted into hydrogen and oxygen; are free from harmful fouling even when utilizing electrolytes such as wastewater, commercial process water, wood-ash water, sea water, fly-ash water, canal and ditch water, or anaerobic digester liquor.    DETAILED DESCRIPTION - Electrolytic cell (2) (I) comprises: a containment vessel configured to contain an electrolyte; at least one electrode (4) configured to be in fluid communication with the electrolyte and in electrical communication with a power supply for producing a first gas and a second gas via electrolysis of the electrolyte; a separator (10) configured to be in fluid communication with the electrolyte and to separate the first gas from the second gas; a first gas collection region in the containment vessel; and a second gas collection region in the containment vessel and substantially concentric with the first gas collection vessel. The first gas collection region is arranged to receive the first gas. The second gas collection region is arranged to receive the second gas. At least one of the first and second gas collection regions has an internal volume that is at least partially conical in shape and configured to distribute pressure in the containment vessel produced by the first gas and the second gas. INDEPENDENT CLAIMS are also included for:    (1) an electrolytic cell (II), comprising the containment vessel, the electrode, a separator configured to be in fluid communication with the electrolyte, and an insulator (24) having a conical shape configured to define a first volume in the containment vessel and a second volume in the containment vessel separated from the first volume, where the first volume is arranged to receive the first gas, the second volume is arranged to receive the second gas, and the first and second volumes are configured to distribute pressure in the containment vessel produced by the first gas and the second gas;    (2) a method (m1) for operating an electrolytic cell, comprising: providing an electrolytic cell; performing electrolysis in the electrolytic cell, where a first gas is produced in a first region in the electrolytic cell and a second gas is produced in a second region in the electrolytic cell during the electrolysis, and the first gas is at least partially confined by a conically shaped surface within the first region; providing a gas collection vessel distinct from the electrolytic cell and in fluid communication with the electrolytic cell; capturing the first gas in the first gas collection vessel prior to substantial expansion of the first gas; expanding the first gas; and capturing work generated from the expansion of the first gas; and    (3) a method (m2) for operating an electrolytic cell, comprising: providing an electrolytic cell; performing electrolysis in the electrolytic cell, where a gas is produced in the electrolytic cell during the electrolysis; and providing a gas collection vessel distinct from the electrolytic cell and in fluid communication with the electrolytic cell via a gas collection path in the electrolytic cell, where the gas collection path is isolated from but extends through a separate gas collection region in the electrolytic cell, and at least a portion of the gas collection path is confined to a volume defined by a conically shaped surface within the electrolytic cell.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of the electrolytic cell.    Electrolytic cell (2)    Electrodes (4, 8)    Separator (10)    Insulator (24)    Catalytic filter (48)