Abstract: The present invention relates to a redox fuel cell comprising an anode and a cathode separated by an ion selective polymer electrolyte membrane; means for supplying a fuel to the anode region of the cell; means for supplying an oxidant to the cathode region of the cell; means for providing an electrical circuit between the anode and the cathode; a non-volatile catholyte solution flowing in fluid communication with the cathode, the catholyte solution comprising a polyoxometallate redox couple being at least partially reduced at the cathode in operation of the cell, and at least partially re-generated by reaction with the oxidant in a regeneration zone after such reduction at the cathode, the catholyte solution further comprising one or more vanadium species that result from the speciation of the polyoxometallate at an elevated temperature and/or pressure, wherein the polyoxometallate is represented by the formula: Xa[ZbMcOd] wherein X is selected from hydrogen, alkali metals, alkaline earth metals, ammonium,

Abstract: This invention provides a redox fuel cell comprising an anode and a cathode separated by an ion selective polymer electrolyte membrane; means for supplying a fuel to the anode region of the cell; means for supplying an oxidant to the cathode region of the cell; means for providing an electrical circuit between the anode and the cathode; a non-volatile catholyte solution flowing in fluid communication with the cathode, the catholyte solution comprising a polyoxometallate redox couple being at least partially reduced at the cathode in operation of the cell, and at least partially re-generated by reaction with the oxidant after such reduction at the cathode, the catholyte solution further comprising vanadium species that result from the speciation of the polyoxometallate at an elevated temperature and/or pressure.

Abstract: A fuel cell system is provided having a plurality of fuel cells combined to form a fuel cell stack. The fuel cell system is characterized in that at least one fuel cell is a redox flow fuel cell having an electrode assembly, which electrode assembly has a proton-permeable separator, which separator is arranged between an anode region and a cathode region. The redox flow fuel cell has a regenerator spatially separated from the electrode assembly, and a water-forming reaction of the redox flow fuel cell occurs in the regenerator. The redox flow fuel cell also has at least one oxidation-fluid delivery unit for feeding oxidation fluid into the regenerator in order to perform the water-forming reaction in the regenerator of the redox flow fuel cell. The redox flow fuel cell also has a pumping circuit, comprising a pumping device and a pumping line, for transporting an electrochemical storage system through the cathode region or the anode region of the redox flow fuel cell and through the regenerator.

Abstract: The present invention relates to a redox fuel cell comprising an anode and a cathode separated by an ion selective polymer electrolyte membrane; means for supplying a fuel to the anode region of the cell; means for supplying an oxidant to the cathode region of the cell; means for providing an electrical circuit between the anode and the cathode; a non-volatile catholyte solution flowing in fluid communication with the cathode, the catholyte solution comprising a polyoxometallate redox couple being at least partially reduced at the cathode in operation of the cell, and at least partially re-generated by reaction with the oxidant in a regeneration zone after such reduction at the cathode, the catholyte solution further comprising one or more vanadium species that result from the speciation of the polyoxometallate at an elevated temperature and/or pressure, wherein the polyoxometallate is represented by the formula: Xa[ZbMcOd] wherein X is selected from hydrogen, alkali metals, alkaline earth metals, ammonium

Abstract: The invention concerns the use as a redox a catalyst and/or mediator in a fuel cell catholyte solution of the compound of Formula (I) wherein: X is selected from hydrogen and from various functional groups; R1-8 are independently selected from hydrogen and various functional groups; wherein R1 and X and/or R5 and X may together form an optionally substituted ring structure; wherein R1 and R2 and/or R2 and R3 and/or R3 and R4 and/or R4 and R8 and/or R8 and R7 and/or R7 and R6 and/or R6 and R5 may together form an optionally substituted ring structure; wherein (L) indicates the optional presence of a linking bond or group between the two neighboring aromatic rings of the structure, and when present may form an optionally substituted ring structure with one or both of R4 and R8; and wherein at least one substituent group of the structure is a charge-modifying substituent.

Abstract: The present invention provides a redox battery comprising a polyoxometallate as at least one redox couple. Preferably, the redox battery comprises two electrodes separated by an ion exchange membrane or other separator; means for supplying a first redox couple to the first electrode region of the cell; means for supplying a second redox couple to the second electrode region of the cell, the potential of the first redox couple being higher than that of the second redox couple, and at least the higher potential redox couple comprising polyoxometallate.

Abstract: This invention provides a redox fuel cell comprising an anode and a cathode separated by an ion selective polymer electrolyte membrane; means for supplying a fuel to the anode region of the cell; means for supplying an oxidant to the cathode region of the cell; means for providing an electrical circuit between the anode and the cathode; a non-volatile catholyte solution flowing in fluid communication with the cathode, the catholyte solution comprising a polyoxometallate redox couple being at least partially reduced at the cathode in operation of the cell, and at least partially re-generated by reaction with the oxidant after such reduction at the cathode, the catholyte solution further comprising vanadium species that result from the speciation of the polyoxometallate at an elevated temperature and/or pressure.

Abstract: This invention provides a redox fuel cell comprising an anode and a cathode separated by an ion selective polymer electrolyte membrane; means for supplying a fuel to the anode region of the cell; means for supplying an oxidant to the cathode region of the cell; means for providing an electrical circuit between the anode and the cathode; a non-volatile catholyte solution flowing fluid communication with the cathode, the catholyte solution comprising a polyoxometallate redox couple being at least partially reduced at the cathode in operation of the cell, and at least partially re-generated by reaction with the oxidant after such reduction at the cathode, the catholyte solution comprising at least one counterion for the polyoxometallate redox couple wherein the at least one counterion comprises one or more divalent ions.

Abstract: This invention provides a redox fuel cell comprising an anode and a cathode separated by an ion selective polymer electrolyte membrane; means for supplying a fuel to the anode region of the cell; means for supplying an oxidant to the cathode region of the cell; means for providing an electrical circuit between the anode and the cathode; a non-volatile catholyte solution flowing fluid communication with the cathode, the catholyte solution comprising a polyoxometallate redox couple being at least partially reduced at the cathode in operation of the cell, and at least partially re-generated by reaction with the oxidant after such reduction at the cathode, the catholyte solution comprising at least about 0.075M of the said polyoxometallate.

Abstract: The invention provides a fuel cell comprising an anode in an anode region of the cell and a cathode in a cathode region of the cell, the anode being separated from the cathode by an ion selective polymer electrolyte membrane, the anode region of the cell being supplied in use thereof with an alcoholic fuel, the cathode region of the cell being supplied in use thereof with an oxidant, the cell being provided with means for generating an electrical circuit between the anode and the cathode and with a non-volatile redox couple in solution in flowing fluid communication with the cathode in the cathode region of the cell, the redox couple being at least partially reduced at the cathode in operation of the cell, and at least partially re-generated by reaction with the oxidant after such reduction at the cathode, the redox couple and/or the concentration of the redox couple in the catholyte solution being selected so that the current density generated by the cell in operation is substantially unaffected by the cross

Abstract: This invention provides a redox fuel cell comprising an anode and a cathode separated by an ion selective polymer electrolyte membrane; means for supplying a fuel to the anode region of the cell; means for supplying an oxidant to the cathode region of the cell; means for providing an electrical circuit between the anode and the cathode; a non-volatile catholyte solution flowing in fluid communication with the cathode, the catholyte solution comprising a redox mediator which is at least partially reduced at the cathode in operation of the cell, and at least partially regenerated by, optionally indirect, reaction with the oxidant after such reduction at the cathode, and a transition metal complex of a multidentate macrocyclic N-donor ligand as a redox catalyst catalysing the regeneration of the mediator.

Abstract: The present invention concerns a fuel cell comprising a cathode in a cathode region of the cell and an anode in an anode region of the cell, the cathode being separated from the anode by an ion selective polymer electrolyte membrane, the cathode region of the cell being supplied in use thereof with an oxidant and a liquid low molecular weight fuel wherein at least some of the liquid low molecular weight fuel in use crosses the polymer electrolyte membrane to supply the anode region of the cell with liquid low molecular weight fuel, the cell being provided with means for generating an electrical circuit between the cathode and the anode.

Abstract: An electrolytic cell comprising an anode in an anode region and a cathode in a cathode region, the anode region and the cathode regions separated by an ion selective polymer electrolyte membrane; an anolyte in flowing fluid communication with the anode, the anolyte comprising water and a redox mediator couple which is at least partially oxidised at the anode in operation of the cell and at least partially reduced by reaction with water after such oxidation at the anode.

Abstract: The invention concerns the use as a redox a catalyst and/or mediator in a fuel cell catholyte solution of the compound of Formula (I) wherein: X is selected from hydrogen and from various functional groups; R1-8 are independently selected from hydrogen and various functional groups; wherein R1 and X and/or R5 and X may together form an optionally substituted ring structure; wherein R1 and R2 and/or R2 and R3 and/or R3 and R4 and/or R4 and R8 and/or R8 and R7 and/or R7 and R6 and/or R6 and R5 may together form an optionally substituted ring structure; wherein (L) indicates the optional presence of a linking bond or group between the two neighbouring aromatic rings of the structure, and when present may form an optionally substituted ring structure with one or both of R4 and R8; and wherein at least one substituent group of the structure is a charge-modifying substituent.

Abstract: A redox fuel cell comprising a catholyte solution comprising at least one non-volatile catholyte component, the catholyte solution comprising a redox mediator couple; and a regeneration zone separate from the membrane electrode assemblies of the fuel cell, the means for supplying an oxidant to the fuel cell being adapted to supply the oxidant to the regeneration zone, the volume of catholyte solution in the regeneration zone being from about 25% to about 90% of the total combined volume of catholyte solution in the regeneration zone and the cathode chambers of the fuel cell.

Abstract: The present invention concerns a fuel cell comprising a cathode in a cathode region of the cell and an anode in an anode region of the cell, the cathode being separated from the anode by an ion selective polymer electrolyte membrane, the cathode region of the cell being supplied in use thereof with an oxidant and a liquid low molecular weight fuel wherein at least some of the liquid low molecular weight fuel in use crosses the polymer electrolyte membrane to supply the anode region of the cell with liquid low molecular weight fuel, the cell being provided with means for generating an electrical circuit between the cathode and the anode.

Abstract: This invention provides a redox fuel cell comprising an anode and a cathode separated by an ion selective polymer electrolyte membrane; means for supplying a fuel to the anode region of the cell; means for supplying an oxidant to the cathode region of the cell; means for providing an electrical circuit between the anode and the cathode; a non-volatile catholyte solution flowing in fluid communication with the cathode, the catholyte solution comprising a redox mediator which is at least partially reduced at the cathode in operation of the cell, and at least partially regenerated by, optionally indirect, reaction with the oxidant after such reduction at the cathode, and a transition metal complex of a multidentate macrocyclic N-donor ligand as a redox catalyst catalysing the regeneration of the mediator.

Abstract: This invention provides a redox fuel cell comprising an anode and a cathode separated by an ion selective polymer electrolyte membrane; means for supplying a fuel to the anode region of the cell; means for supplying an oxidant to the cathode region of the cell; means for providing an electrical circuit between the anode and the cathode; a non-volatile catholyte solution flowing fluid communication with the cathode, the catholyte solution comprising a polyoxometallate redox couple being at least partially reduced at the cathode in operation of the cell, and at least partially re-generated by reaction with the oxidant after such reduction at the cathode, the catholyte solution comprising at least one counterion for the polyoxometallate redox couple wherein the at least one counterion comprises one or more divalent ions.

Abstract: The invention provides a fuel cell comprising an anode in an anode region of the cell and a cathode in a cathode region of the cell, the anode being separated from the cathode by an ion selective polymer electrolyte membrane, the anode region of the cell being supplied in use thereof with an alcoholic fuel, the cathode region of the cell being supplied in use thereof with an oxidant, the cell being provided with means for generating an electrical circuit between the anode and the cathode and with a non-volatile redox couple in solution in flowing fluid communication with the cathode in the cathode region of the cell, the redox couple being at least partially reduced at the cathode in operation of the cell, and at least partially re-generated by reaction with the oxidant after such reduction at the cathode, the redox couple and/or the concentration of the redox couple in the catholyte solution being selected so that the current density generated by the cell in operation is substantially unaffected by the cross

Abstract: This invention provides a redox fuel cell comprising an anode and a cathode separated by an ion selective polymer electrolyte membrane; means for supplying a fuel to the anode region of the cell; means for supplying an oxidant to the cathode region of the cell; means for providing an electrical circuit between the anode and the cathode; a non-volatile catholyte solution flowing fluid communication with the cathode, the catholyte solution comprising a polyoxometallate redox couple being at least partially reduced at the cathode in operation of the cell, and at least partially re-generated by reaction with the oxidant after such reduction at the cathode, the catholyte solution comprising at least about 0.075M of the said polyoxometallate.