NOVELTY - Fuel cell system (10) comprises: an anode compartment (12) comprising ammonia borane derivatives (I) as fuel; a cathode compartment (14) comprising an oxidant; and a separator (20) interposed between the cathode and the anode compartments, where at least one of the anode or the cathode comprises a catalyst layer (50) comprising a non-noble metal and/or a nonmetallic substance.    USE - The fuel cell system is useful: in a power plant and a portable power source; for powering vehicles and electricity-consuming devices (all claimed) e.g. pager and notebook computer; and e.g. as a component in a power source in e.g. a spacecraft.    ADVANTAGE - The fuel cell system: exhibits an open circuit potential higher than 2 volts and a power output of greater than or equal to 1 watt; exhibits fast kinetic level; has high stability; is cost-effective; consists of relatively simple catalysts; and exhibits improved performance.    DETAILED DESCRIPTION - Fuel cell system comprises: an anode compartment comprising ammonia borane derivatives of formula (R1R2R3N-BR4R5R6) (I) as fuel; a cathode compartment comprising an oxidant; and a separator interposed between the cathode and the anode compartments, where at least one of the anode or the cathode comprises a catalyst layer comprising a non-noble metal and/or a nonmetallic substance. INDEPENDENT CLAIMS are also included for:    (1) a method of operating the fuel cell system comprising contacting the anode compartment with an anode electrolyte solution comprising (I) or their salts, hydrates or solvates and, at the same time, contacting the cathode compartment with a cathode electrolyte solution comprising the oxidant, and electrochemically reacting (I) and the oxidant;    (2) a method of producing electrical energy comprising electrochemically reacting (I) or their salts, hydrates or solvates and the oxidant, where (I) is contacted with the anode compartment and the oxidant is contacted with the cathode compartment;    (3) a process of producing an electrode having a catalyst layer comprising copper nanoparticles comprising: contacting an electrode having a catalyst layer comprising copper with a solution containing a copper salt and base to obtain a layer of the copper salt on the electrode; and contacting the electrode having the layer with phosphinic acid or its salt;    (4) a power plant comprising the fuel cell system;    (5) a vehicle fueled by the fuel cell system; and    (6) a portable power source comprising the fuel cell system.    R1-R6 = H (preferred), alkyl, alkenyl, alkynyl, heteroalicyclic, alkoxy or amine.    Provided that at least one of R4-R6 is H.    DESCRIPTION OF DRAWING(S) - The figure is a schematic illustration of the fuel cell system.    Fuel cell system (10)    Anode compartment (12)    Cathode compartment (14)    Separator (20)    Catalyst layer (50)