Method and apparatus for energy efficient electrochemical production of hydride gases

An electrochemical apparatus for generation of hydride gas, comprising:

• an electrochemical reactor having a pressure vessel having an interior containing a cathode, an anode, and an electrolyte, wherein the cathode includes a first amount of an electrically conductive precursor material that is reducible to form the hydride gas;
• wherein the conductive precursor material is in particulate form, and wherein the cathode includes a packed bed of particles of the conductive precursor material;
• and
• wherein (i) a bottom of the packed bed is spaced from and faces a top surface of the anode, the electrolyte contacts and spans between the bottom of the packed bed and the top surface of the anode, the reactor is configured to conduct current through the electrolyte between the bottom of the packed bed and the top surface of the anode, and the bottom of the packed bed and the top surface of the anode together form an electrochemical reaction cross-section area of the reactor, and (ii) the packed bed and anode are arranged such that at least 80% by weight of the particles of the packed bed can be consumed during generation of the hydride gas by the apparatus without changing the electrochemical reaction cross-section area of the reactor.