NOVELTY - Electrochemical method for releasing hydrogen from at least one hydride or hydroxide based on metal cation, comprises (a) arranging two electrically conductive electrodes spaced apart in facing relationship and in contact with an electrolyte suitable for ion conduction of at least one metal cation, where the electrodes comprise a condensed powder mixture that comprises the hydride or hydroxide based on metal cation, and (b) applying a suitable electric potential difference between electrodes to accelerate hydrogen release reaction at the electrodes.    USE - The electrochemical method is useful for releasing hydrogen from at least one hydride or hydroxide based on metal cation.    ADVANTAGE - The method: releases hydrogen at low temperature; and makes use of metal hydrides that have high gravimetric storage density.    DETAILED DESCRIPTION - Electrochemical method for releasing hydrogen from at least one hydride or hydroxide based on metal cation, comprises (a) arranging two electrically conductive electrodes spaced apart in facing relationship and in contact with an electrolyte suitable for ion conduction of at least one metal cation, where the electrodes comprise a condensed powder mixture that comprises the hydride or hydroxide based on metal cation, which is intimately mixed with an electrically conductive material, and (b) applying a suitable electric potential difference between electrodes to accelerate hydrogen release reaction at the electrodes. INDEPENDENT CLAIMS are also included for:    (1) storing hydrogen, comprising applying suitable electric potential difference between the spaced apart first- and second electrodes, where the electrodes comprise hydride-forming composition, and contacting the first- and second electrodes with the electrolyte, where electrodes and the electrolyte are in hydrogen atmosphere; and    (2) a cell (10) for releasing and storing hydrogen, comprising two spaced apart opposing electrodes that are arranged for connecting with an external electrical source suitable for producing electric potential difference between the electrodes, where (i) the electrodes are kept separated by a porous electrically non-conductive spacer, and (ii) each electrode is in contact with a flowable non-aqueous ion conductor suitable for transporting selected ion species.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic representation of the cell for electrochemical production of hydrogen with electrodes and a hydrogen sensor.    Cell (10)    Electrolyte (12)    Container (14)    Electrode (16)    Hydrogen sensor (24)