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: 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: 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 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 N-donor ligand as a redox catalyst catalyzing the regeneration of the mediator the multi-dentate N-donor ligand comprising at least one heterocyclic substituent selected from pyrrole, imidazole, 1,2,3-triazole, 1,2,4-triazole, pyrazole, pyridazine, pyrimidine, pyrazine, indole, tetrazole, quinoline, i

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 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: 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 N-donor ligand as a redox catalyst catalysing the regeneration of the mediator the multi-dentate N-donor ligand comprising at least one heterocyclic substituent selected from pyrrole, imidazole, 1,2,3-triazole, 1,2,4-triazole, pyrazole, pyridazine, pyrimidine, pyrazine, indole, tetrazole, quinoline, i

Abstract: 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 catholyte solution comprising a modified ferrocene species comprising at least one bridging unit between the cyclopentadienyl rings, the modified ferrocene species 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.

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.