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Fuel Cell (Reaction Mechanisms (Alkaline electrolyte, By product, Acid…

- - - - Advantages
        
        Quick start up
        
        No corrosion liquid involved
        
        Low temperature operation
        
        Allows compact cells due to thin membrane-electrode assemblies
      - Uses a polymeric electrolyte
      - Known as polymer electrolyte membrane
      - Proton-conducting polymer forms the heart of each cell
      - Electrodes usually made of porous carbon with catalytic platinum
      - Cathode : positive electrode
        
        Conducts electrons back from external circuit to catalyst
        
        Can recombine with hydrogen ions and oxygen to form water
        
        Has channel etched into it that distribute oxygen to surface of catalyst
      - Anode : negative electrodes
        
        so they can be used in an external circuit
        
        Has channel etched into it that disperse hydrogen gas equally over surface of catalyst
        
        Conducts electrons that are freed from hydrogen molecules
      - Electrolyte
        
        proton exchange membrane
        
        Only conduct positively charged ions
        
        Membrane blocks electrons
      - Catalyst
        
        Facilitates reaction of hydrogen and oxygen
        
        usually made of platinum powder very thinly coated onto carbon paper or cloth
    - - Electrolyte
        
        liquid phosphoric acid
      - At anode
        
        Hydrogen splits into 2 hydrogen ions
        
        2e pass through external circuit to cathode
      - At cathode
        
        H+e+O -> H2O
    - - Lower specific mass and volume
      - Higher energy density
      - Adaptable to automotive / smaller power units
      - Higher dynamic in power output
      - Faster operational behaviour
  - - - Not limited to use pure hydrogen as fuel
      - Can use gaseous / gasified hydrocarbond
      - Can be equipped with facilities for internal reforming of the fuel gas
      - High temperature -> thermally slow -> slow in load changes -> suitable for stationary applications in the field of energy conversion