NOVELTY - The cell (1) has a providing unit for providing an electrical circuit between an anode and a cathode (3). Non-volatile cathode solution flows in fluid communication with the cathode and comprises polyoxometallate redox partially reduced at the cathode in operation of the cell and partially regenerated by reaction with oxidant in a regeneration zone after reduction at the cathode. The catholyte solution comprises vanadium species that result from speciation of the polyoxometallate at elevated temperature and pressure, where the polyoxometallate is represented by predetermined formula.    USE - Redox fuel cell for automotive and portable electronics/industries.    ADVANTAGE - The cell is efficient, in expensive to manufacture and assemble, small in construction, found practical, commercial utility in automotive and portable electronics, uses in expensive and environmentally friendly materials, yields adequate and sufficiently maintainable current densities and cell potentials and operates at low temperature, and does not produce unwanted by-products and poflutants and noxious materials.    DETAILED DESCRIPTION - The predetermined formula utilizes element-Xa selected from a group consisting of hydrogen, alkali metals, alkaline earth metals, ammonium and transition metal ions, element-Z is selected from group consisting of Boron, Phosphorus, Sulfur, Arsenic, Silicon, Germanium, nickel, Rhodium, Tin, aluminum, copper, indium, bromium, Fluorine, Iron, cobalt, chromium, zinc, hydrogen, Tellurium, manganese and Selenium and element-M selected from a group consisting a vanadium, Molybdenum, Tungsten, Niobium, Tantalum, Manganese, iron, cobalt, chromium, nickel, zinc, Rhodium, Ruthenium, Titanium, aluminum, gallium and indium.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a cathode compartment of a fuel cell.    Redox fuel cell (1)    Polymer electrolyte membrane (2)    Cathode (3)    Oxidant inlet of cathode gas reaction chamber (4)    Cathode gas reaction chamber (5)    Exhaust (6)    Catholyte resevoir (7)    Cathode inlet channel (8)    Cathode outlet channel (9)