Direct liquid fuel cell having ammonia borane, hydrazine, derivatives thereof or/and mixtures thereof as fuel

A fuel cell system comprising an anode compartment which comprises an anode having a copper catalyst layer, a cathode configured as an air cathode and a separator interposed between said anode and said cathode, operable by an amine-derived fuel and oxygen (or air) is disclosed. Further disclosed are fuel cell systems comprising an anode compartment which comprises an anode having a copper catalyst layer, a cathode and a separator interposed between said anode and said cathode, which are operable by a mixture of two types of amine-derived compounds (e.g., ammonia borane, hydrazine and derivatives thereof). Also disclosed are methods of producing electric energy by, and electric-consuming devices containing and operable by, the disclosed fuel cell systems.