1. A redox fuel cell comprising:
an anode region comprising an anode and a cathode region comprising a cathode, said regions being separated by an ion selective polymer electrolyte membrane;
a fuel passage through which fuel is supplied to the anode region of the cell;
an oxidant inlet that supplies an oxidant to the cathode region of the cell;
an electrical circuit between the anode and the cathode; and
a catholyte solution comprising at least one non-volatile catholyte component 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, the catholyte solution further comprising a complexed multidentate N-donor ligand as at least one of said redox mediator and as a redox catalyst catalysing the regeneration of the said mediator, the multi-dentate N-donor ligand comprises at least one heterocyclic substituent selected from pyrrole, imidazole, 1,2,3-triazole, 1,2,4-triazole, pyrazole, pyridazine, pyrimidine, pyrazine, indole, tetrazole, quinoline, isoquinoline and from alkyl, alkenyl, aryl, cycloalkyl, alkaryl, alkenaryl, aralkyl, aralkenyl groups substituted with one or more of the aforesaid heterocyclic groups.
2. A redox fuel cell according to claim 1 wherein the multidentate N-donor ligand comprises a non-polymeric molecule containing up to 8 nitrogen atoms capable of coordinating to a transition metal centre.
3. A redox fuel cell according to claim 2 wherein the ligand may coordinate through each or any of the nitrogen atoms.
4. A redox fuel cell according to claim 2 wherein the multidentate N-donor ligand comprises from three to six nitrogen atoms capable of coordinating to a transition metal centre.
5. A redox fuel cell according to claim 4 wherein the N-donor ligand comprises from four to six nitrogen atoms capable of coordinating to a transition metal centre.
6. A redox fuel cell according to claim 5 wherein the N-donor ligand comprises five or six nitrogen atoms capable of coordinating to a transition metal centre.
7. A redox fuel cell according to claim 1 wherein the heterocyclic substituent comprises one or more substituent functional groups thereon, at any position or positions on the ring.
8. A redox fuel cell according to claim 7 wherein the substituent group is selected from alkyl, aryl, alkenyl, alkynyl, amine, protonated amine, quaternary amine, sulfate, sulfonate, sulfonic acid, phosphate, phosphonate, phosphonic acid, carboxylate, carboxylic acid, halides and combinations of two or more thereof on the same or on different positions on the ring.
9. A redox fuel cell according to claim 8 wherein each substituent group is spaced from the heterocyclic substituent by one or more spacer elements.
10. A redox fuel cell according to claim 9 wherein the or each spacer element is selected from straight or branched chain alkyl, alkenyl, aryl, cycloalkyl, alkaryl, aralkyl, aralkenyl and combinations of two or more thereof.
11. A redox fuel cell according to claim 1 wherein the N-donor ligand comprises the structure:
wherein X, Y and Z are optionally substituted N-containing heterocycles, at least one of which is selected from pyrrole, imidazole, 1,2,3-triazole, 1,2,4-triazole, pyrazole, pyridazine, pyrimidine, pyrazine, indole, tetrazole, quinoline, isoquinoline and from alkyl, alkenyl, aryl, cycloalkyl, alkaryl, alkenaryl, aralkyl, aralkenyl groups substituted with one or more of the aforesaid cyclic groups;
wherein A, B and C are spacer elements independently selected from straight or branched chain alkyl, alkenyl, aryl, cycloalkyl, alkaryl, aralkyl or aralkenyl and
wherein a, b and c can independently be any integer from 0 to 5.
12. A redox fuel cell according to claim 11 wherein a, b and c are independently any integer from 1 to 3.
13. A redox fuel cell according to claim 11 wherein one or more of A, B and C are independently substituted with one or more substituent functional groups at any position or positions on the ring.
14. A redox fuel cell according to claim 13 wherein the or each substituent group is independently selected from alkyl, aryl, alkenyl, alkynyl, amine, protonated amine, quaternary amine, sulfate, sulfonate, sulfonate, sulfonic acid, sulfonic acid, phosphate, phosphonate, phosphonic acid, carboxylate, carboxylic acid andor halides.
15. A redox fuel cell according to claim 11 wherein the N-donor ligand is selected from:
16. A redox fuel cell according to claim 1 wherein the N-donor ligand comprises the structure:
wherein R1 to R5 are independently any group or atom, with from two to five R1 to R5 comprising organic groups containing an N donor atom, with from one to five, of those N donor atoms belonging to one or more optionally substituted heterocycles, at least one of which is selected from pyrrole, imidazole, 1,2,3-triazole, 1,2,4-triazole, pyrazole, pyridazine, pyrimidine, pyrazine, indole, tetrazole, quinoline, isoquinoline and from alkyl, alkenyl, aryl, cycloalkyl, alkaryl, alkenaryl, aralkyl, aralkenyl groups substituted with one or more of the aforesaid cyclic groups.
17. A redox fuel cell according to claim 16 wherein any one or more of R1 to R5 is substituted with one or more substituent functional groups at any position or positions on the ring.
18. A redox fuel cell according to claim 17 wherein the or each substituent groups is independently selected from straight or branched chain alkyl, aryl, alkenyl, alkynyl, amine, protonated amine, quaternary amine, sulfate, sulfonate, sulfonic acid, phosphate, phosphonate, phosphonic acid, carboxylate, carboxylic acid, and halides and combinations of two or more thereof.
19. A redox fuel cell according to claim 17 wherein each substituent group is spaced from the heterocycle by any number of suitable spacer elements.
20. A redox fuel cell according to claim 19 wherein the or each spacer element is independently selected from optionally substituted straight or branched chain, alkyl, alkenyl, aryl, cycloalkyl, alkaryl, aralkyl, aralkenyl or combinations of two or more thereof.
21. A redox fuel cell according to claim 16 wherein the N-donor ligand is selected from:
22. A redox fuel cell according to claim 1 wherein the N-donor ligand has the structure:
wherein n is any integer from 1 to 10; and
wherein one to four of R1 to R4 are organic groups containing an N donor atom, with at least one, and up to four, of those N-donor atoms belonging to an optionally substituted heterocycle, at least one of which is selected from pyrrole, imidazole, 1,2,3-triazole, 1,2,4-triazole, pyrazole, pyridazine, pyrimidine, pyrazine, indole, tetrazole, quinoline, isoquinoline and from alkyl, alkenyl, aryl, cycloalkyl, alkaryl, alkenaryl, aralkyl, aralkenyl groups substituted with one or more of the aforesaid cyclic groups;
and wherein R1-R4 can be the same or different.
23. A redox fuel cell according to claim 22 wherein the heterocycle contains any number of substituent functional groups at any position or positions on the ring.
24. A redox fuel cell according to claim 23 wherein the or each substituent group is independently selected from straight or branched chain alkyl, aryl, alkenyl, alkynyl, amine, protonated amine, quaternary amine, sulfate, sulfonate, sulfonic acid, phosphate, phosphonate, phosphonic acid, carboxylate, carboxylic acid, halides and combinations of one or more thereof.
25. A redox fuel cell according to claim 24 wherein each substituent group is spaced from the heterocycle by any number of suitable spacer elements.
26. A redox fuel cell according to claim 25 wherein the or each spacer element is independently selected from optionally substituted straight or branched chain alkyl, alkenyl, aryl, cycloalkyl, alkaryl, aralkyl or aralkenyl.
27. A redox fuel cell according to claim 22 wherein the N-donor ligand is selected from:
28. A fuel cell according to claim 1 wherein the catholyte solution comprises the complexed multidentate N-donor ligand as said redox mediator, and as said redox catalyst.
29. A fuel cell according to claim 1 wherein the catholyte solution comprises a redox mediator and the complexed multidentate N-donor ligand as redox catalyst.
30. A fuel cell according to claim 1 wherein the catholyte solution comprises the complexed multidentate N-donor ligand as redox mediator and a further material as redox catalyst.
31. A fuel cell according to claim 1 wherein in operation thereof the oxidant is reduced in the catholyte solution by the redox catalyst.
32. A fuel cell according to claim 31 wherein the resulting oxidised redox catalyst is effective at least partially to oxidise the mediator to regenerate the mediator after its reduction at the cathode.
33. A fuel cell according to any one of claim 1 wherein the catholyte solution is an aqueous solution.
34. A fuel cell according to claim 1 wherein the complexed multidentate N-donor ligand comprises a transition metal complex of the multidentate N-donor ligand.
35. A fuel cell according to claim 34 wherein the multidentate N-donor ligand comprises one or more N-donor atoms which do not coordinate with the transition metal.
36. A fuel cell according to claim 1 wherein the ion selective polymer electrolyte membrane is a cation selective membrane which is selective in favour of protons versus other cations.
37. A fuel cell according to claim 36 wherein the catholyte is acidic.
38. A fuel cell according to claim 1 wherein the ion selective polymer electrolyte membrane is an anion selective membrane.
39. A fuel cell according to claim 38 wherein the catholyte is alkaline.
40. A fuel cell according to claim 1 wherein the ion selective polymer electrolyte membrane is a bimembrane
41. A fuel cell according to claim 1 wherein the redox mediator comprises a modified ferrocene species.
42. A catholyte for use in a fuel cell according to claim 1, the catholyte comprising a redox mediator and a redox catalyst, a multidentate N-donor ligand complex being provided in the catholyte as the said redox mediator andor as the said redox catalyst.
43. A method of operating a proton exchange membrane fuel cell comprising the steps of:
forming H+ ions at an anode situated adjacent to a proton exchange membrane;
supplying the catholyte of claim 42 with its redox mediator in an oxidised state and its redox catalyst in a reduced state to a cathode situated oppositely adjacent to the proton exchange membrane; and
allowing the mediator to become reduced upon contact with the cathode concomitantly with H+ ions passing through the membrane to balance charge.
44. The redox fuel cell according to claim 16, wherein from three to five of the R1 to R5 groups comprise organic groups containing an N donor atom, and three to five of those N donor atoms belong to one or more of said optionally substituted heterocycles.
45. The redox fuel cell according to claim 22, wherein n is any integer from 1 to 5.
46. The redox fuel cell according to claim 22, wherein n is any integer from 1 to 3.
47. The redox fuel cell according to claim 22, wherein n is any integer from 1 to 3
48. The redox fuel cell according to claim 22, wherein two to four of R1 to R4 are organic groups containing an N donor atom from three to four of those N-donor atoms belonging to said optionally substituted heterocycle.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A positioning system for a disc stack array, comprising:
a clamp including an axial catch, the clamp configured to bear against the disc stack array and to align substantially along an axis of the disc stack array; and
a retaining arrangement for engaging the axial catch, wherein the retaining arrangement includes one or more radially movable members that engage and secure the axial catch in an engagement position and disengage the axial catch in a disengagement position.
2. The positioning system according to claim 1, the retaining arrangement further including:
a spindle hub;
a screw having a first threaded portion threadably engaging the threads in interior of the spindle hub; the screw further having a second threaded portion, a first surface, a second surface, and a cam portion;
a nut threadably engaging the second threaded portion of the screw, the nut having a plurality of ports each having an outer opening, at least two of the ports each housing a ball, the balls being the radially moveable member(s); and
wherein the balls are housed between the first surface of the screw and the outer opening of the port within which each ball is housed when the axial catch is in the engagement position and the balls are housed between the second surface of the screw and the outer opening of the port within which each ball is housed when the axial catch is in the disengagement position.
3. The positioning system according to claim 1, the retaining arrangement further including:
a spindle hub;
a plunger disposed in the interior of the spindle hub, the plunger having a plurality of ports, disposed adjacent a collar having a first and a second surface, at least two of the ports each housing a ball, the balls being the radially moveable member(s); and
wherein each of the balls is housed between the first surface of the collar and its port when the axial catch is in the engagement position and ball is housed between the second surface of the collar and its port when the axial catch is in the disengagement position.
4. The positioning system according to claim 1 wherein the radially movable member(s) are housed in ports spaced at 60 degree intervals around the retaining arrangement.
5. The positioning system of claim 1, wherein the retaining arrangement includes six ports spaced at 60 degree intervals and further includes balls housed within alternating ones of the six ports, the balls being the radially moveable member(s).
6. The positioning system of claim 1, wherein the radially moveable members move farther from the axis to enter the engagement position and move closer to the axis to enter the disengagement position.
7. A releasable, rotatable disc positioning system comprising:
a spindle hub;
a disc stack on the spindle hub, the disc stack including at least one disc;
a disc clamp including an axial catch; and
a retaining arrangement for engaging the axial catch, wherein the retaining arrangement includes a plurality of radially movable members that engage and secure the axial catch in an engagement position and disengage the axial catch in a disengagement position.
8. The disc positioning system according to claim 7, wherein the retaining arrangement further comprises:
a screw having a first threaded portion threadably engaging several threads on an interior of the spindle hub; the screw further having a second threaded portion, a first surface, a second surface, and a cam portion; and
a nut threadably engaging the second threaded portion of the screw, the nut having a plurality of ports each having an outer opening, and at least two of the ports each housing a ball, the balls being the radially moveable members;
wherein each of the balls is housed between the first surface of the screw and the outer opening of the port within which each of the balls is housed when the axial catch is in the engagement position and each of the balls is housed between the second surface of the screw and the outer opening of the port within which each of the balls is housed when the axial catch is in the disengagement position.
9. The disc positioning system according to claim 7, the retaining arrangement further including:
a plunger disposed in the interior of the spindle hub, the plunger having a plurality of ports, wherein the ports are disposed adjacent a collar having a first and a second surface, at least two of the ports each housing a ball, the balls being the radially moveable members; and
wherein the balls are housed between the first surface of the collar and the port when the axial catch is in the engagement position and wherein the balls are housed between the second surface of the collar and the port when the axial catch is in the disengagement position.
10. The disc positioning system according to claim 7 wherein the radially movable members are each housed in a respective port, the ports being distributed around the retaining arrangement.
11. The disc positioning system according to claim 7 wherein the retaining arrangement includes a greater number of the ports than of the radially movable members.
12. The disc positioning system according to claim 7 wherein the radially moveable members move outwardly towards the spindle hub to enter the engagement position and move inwardly away from the spindle hub to enter the disengagement position.
13. A disc clamp arrangement comprising:
a disc clamp having an axial catch for securing an information storage disc on a spindle hub in a disc drive; and
retaining means for removably securing the disc clamp with the spindle hub.
14. The disc clamp assembly of claim 13 wherein the retaining means are disposed within an interior of the spindle hub.
15. The disc clamp assembly of claim 13 wherein the retaining means consists of an axial catch and a plurality of balls engaging the axial catch to removably secure the disc clamp to the spindle hub.
16. The disc clamp assembly of claim 13 wherein the retaining means includes a plurality of circumferentially distributed ports each for housing a respective radially movable member.
17. The disc clamp assembly of claim 13 wherein the ports are spaced at regular intervals around the spindle hub.
18. The disc clamp assembly of claim 13 wherein the retaining means includes radially moveable members move outwardly towards the spindle hub to enter an engagement position and move inwardly away from the spindle hub to enter the disengagement position.