NOVELTY - An integrated hybrid electrochemical device comprises a first set of electrodes in a housing which, in the charged state, comprises a nickel oxyhydroxide electrode, and a dissociable metal-hydride electrode; a second set of electrodes within the housing comprising a hydrogen-gas diffusion electrode and an oxygen/air gas-diffusion electrode; and an alkali metal hydroxide electrolyte common to all of the electrodes.    USE - As e.g. battery, fuel cell, electrolyzer.    ADVANTAGE - The hybrid electrochemical device of the invention has the ability to achieve a higher output voltage than the fuel cell alone at lower current densities and high battery electrode state of charge. It can provide in-situ local charging (chemically and electrochemically) of the battery electrodes.    DETAILED DESCRIPTION - An integrated hybrid electrochemical device comprises housing (2); a first set of electrodes (4) in the housing which, in the charged state, comprises a nickel oxyhydroxide (NiOOH) electrode (20), and a dissociable metal-hydride electrode (14); a second set of electrodes (6) within the housing comprising a hydrogen-gas diffusion electrode (16) and an oxygen/air gas-diffusion electrode (22); an alkali metal hydroxide electrolyte common to all of the electrodes; an oxygen/air plenum (10) confronting the oxygen/air gas-diffusion electrode for supplying air to the air oxygen/gas-diffusion electrode; and a hydrogen plenum (8) confronting the hydrogen gas-diffusion electrode for supplying hydrogen to the hydrogen gas-diffusion electrode.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic side view of a hybrid electrochemical device of the invention.    Housing (2)    First set of electrodes (4)    Second set of electrodes (6)    Hydrogen plenum (8)    Oxygen/air plenum (10)    Electrolyte compartment (12)    Metal-hydride electrode (14)    Hydrogen-gas diffusion electrode (16)    Current collector (18, 24)    NiOOH electrode (20)    Oxygen/air gas-diffusion electrode (22)    Hydrogen inlet (25)    Hydrogen outlet (26)    Nonconductive frame (27)    Oxygen/air inlet (28)    Oxygen/air outlet (30)    Electrolyte compartment inlet (32)    Electrolyte compartment outlet (34)    Electrically conductive terminal tabs (36, 38)