Actuators using double-layer charging of high surface area materials
First Claim
1. An actuator comprising:
- at least one ionically conducting and electronically insulating electrolyte; and
at least two electronically conducting electrodes separated by said at least one electrolyte, at least one electrode of said at least two electronically conducting electrodes being a porous solid with a skeletal density in gm/cm3 of ρ
having an accessible gravimetric surface area of at least 150 ρ
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1 m2/gm and an accessible gravimetric capacitance of at least 5 ρ
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1 F/gm and having pores containing an electrolyte that is ionically conducting, the at least one electrode undergoing a response that provides, in whole or in part, an actuator output upon non-faradaic charge injection responsive to application of an electrical voltage between said at least two electronically conducting electrodes.
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Accused Products
Abstract
Actuators are described that operate as a result of double-layer charge injection in electrodes having very high gravimetric surface areas and gravimetric capacitances. The actuator output of the actuators may be a mechanical displacement that can be used to accomplish mechanical work. As a result of the non-faradaic process and the actuator materials utilized, such as carbon nanotubes, the actuators have improved work capacity, power density, cycle life, and force generation capabilities. Other benefits include low voltage operation and high temperature performance. The actuators also convert a mechanical energy input to an electrical energy output. The actuators may be used to control either thermal, electrical or fluid transport or cause either the switching, phase shift, or attenuation of electromagnetic radiation.
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Citations
77 Claims
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1. An actuator comprising:
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at least one ionically conducting and electronically insulating electrolyte; and
at least two electronically conducting electrodes separated by said at least one electrolyte, at least one electrode of said at least two electronically conducting electrodes being a porous solid with a skeletal density in gm/cm3 of ρ
having an accessible gravimetric surface area of at least 150 ρ
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1 m2/gm and an accessible gravimetric capacitance of at least 5 ρ
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1 F/gm and having pores containing an electrolyte that is ionically conducting,the at least one electrode undergoing a response that provides, in whole or in part, an actuator output upon non-faradaic charge injection responsive to application of an electrical voltage between said at least two electronically conducting electrodes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
(a) crystallizing spheres of a first material into a porous first structure having three-dimensional periodicity and voids between the spheres;
(b) infiltrating the porous first structure with a second material to form a composite structure of the first and second materials; and
(c) removing the first material from the composite structure to form a porous second structure comprising the second material.
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9. The actuator of claim 8, wherein the second material is either comprised of graphite or a precursor to graphite.
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10. The actuator of claim 2, wherein the at least one electrode is part of either an optical switch in an electroptical circuit, an electrochromic element on a display, or an electrically switchable window.
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11. The actuator of claim 3, wherein the at least one electrode is one part of a fluid control valve, wherein valve operation results from an electrically controlled change in surface energy of the at least one electrode that is in a form of either a pipe or a sheet.
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12. The actuator of claim 1, wherein the at least one electrode comprises a form of carbon.
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13. The actuator of claim 12, wherein the form of carbon comprises either single-wall, multi-wall, or scroll carbon nanotubes.
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14. The actuator of claim 12, wherein the at least one electrode is in the form of a sheet comprising single-wall carbon nanotubes.
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15. The actuator of claim 12, wherein the form of carbon comprises separated sheets of graphite dispersed in a solid electrolyte and percolated in the solid electrolyte.
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16. The actuator of claim 1, wherein one or more of said at least two electronically conducting electrodes comprises a conducting organic polymer.
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17. The actuator of claim 1, wherein two electrodes of said at least two electronically conducting electrodes are electrolyte filled porous solids that (a) undergo an actuator response upon non-faradaic charge injection and (b) have an accessible gravimetric surface area of at least 150 ρ
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1 m2/gm and an accessible gravimetric capacitance of at least 5 ρ
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1 F/g.
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18. The actuator of claim 2, that is an electromechanical actuator providing mechanical displacement capable of accomplishing mechanical work in response to application of the electrical voltage between said at least two electronically conducting electrodes.
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19. The actuator of claim 18, wherein the at least one electrode is a sheet comprised of carbon single-wall nanotubes, wherein an in-plane Young'"'"'s modulus of the sheet is at least 0.5 GPa.
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20. The actuator of claim 18, wherein an electrical energy is generated as an output from said at least two electronically conducting electrodes responsive to one or more time varying mechanical strains on the at least one electrode.
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21. The actuator of claim 2, wherein said at least two electronically conducting electrodes each comprise a porous thermoelectric having a thermoelectric coefficient that is electrically switched by substantially non-faradaic charge injection.
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22. The actuator of claim 1, wherein said at least two electronically conducting electrodes comprise a working electrode and a counter electrode, the working and counter electrodes and said at least one electrolyte being interpenetrating elements in a single composite structure.
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23. The actuator of claim 1, comprising the at least one electrode that operates non-faradaically and a counter electrode that operates faradaically.
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24. The actuator of claim 23, wherein the at least one electrode is predominately surface coated with ions during actuation and the counter electrode is a solid electrode that is predominately infiltrated with ions that insert therein during actuation.
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25. The actuator of claim 1, wherein above 25% of pore volume of the at least one electrode that is either two-dimensionally accessible or three-dimensionally accessible by the electrolyte that is ionically conducting has an effective radius of above 20 Å
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26. The actuator of claim 1, wherein an electrical energy is chemically or photochemically generated using said at least two electronically conducting electrodes as one of battery electrodes, fuel cell electrodes, and electrodes of a photo-rechargeable battery.
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27. The actuator of claim 26, wherein said at least two electronically conducting electrodes are electrodes of a photo-rechargeable battery, one of said at least two electronically conducting electrodes being a transition metal chalcogenide.
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28. The actuator of claim 26, wherein said at least two electronically conducting electrodes are battery electrodes, wherein one of said at least two electronically conducting electrodes is comprised of lithium and another of said at least two electronically conducting electrodes that provides the actuator response is comprised of carbon nanofibers, the electrolyte that is ionically conducting and electronically insulating being comprised of a lithium salt and either thionyl chloride (SOCl2) or SO2.
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29. The actuator of claim 28, wherein the actuator response is mechanical displacement.
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30. An electromechanical actuator comprising:
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at least one ionically conducting and electronically insulating electrolyte; and
at least two electronically conducting electrodes separated by said at least one electrolyte, at least one electrode of said at least two electronically conducting electrodes being a porous solid having an accessible gravimetric surface area of at least 150 m2/gm and an accessible gravimetric capacitance of at least 5 F/gm, having a mechanical modulus of at least 0.5 GPa and having pores containing an electrolyte that is ionically conducting, the at least one electrode undergoing a dimensional change that provides, in whole or in part, an actuator output upon non-faradaic charge injection responsive to application of an electrical voltage between said at least two electronically conducting electrodes. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67)
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68. A mechanical actuator for converting chemical energy to electrical energy and converting the electrical energy to a mechanical displacement, comprising:
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first and second electrodes that are electronically conductive and contain a catalyst for oxidation or reduction, said first and second electrodes being porous and filled with an electrolyte, at least one electrode of said first and second electrodes having a gravimetric surface area of at least 150 m2/gm and undergoing a dimensional change responsive to non-faradaic charging;
an electrolyte separating said first and second electrodes, said separating electrolyte being substantially gas impermeable, ionically conductive, and electronically insulating;
means for contacting said first electrode with a first reactant that is oxidizable; and
means for separately contacting said second electrode with a second reactant that is reducible, the at least one electrode being mechanically displaced responsive to at least one of controlling flow of said first and second reactants to said first and second electrodes and electrically connecting said first and second electrodes either directly or indirectly. - View Dependent Claims (69, 70, 71, 72, 73)
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74. An electromechanical microactuator comprising:
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a first electrode that is electronically conducting and having a thickness in a narrowest dimension of less than 10 nm, a gravimetric surface area of at least 150 m2/gm, and a capacitance of at least 5 F/gm;
a second electrode that is electronically conducting serving as a counter electrode to said first electrode; and
an electronically insulating electrolyte providing an ionically conducting path between said first and second electrodes, said first electrode being mechanically displaced responsive to application of a voltage between said first and second electrodes. - View Dependent Claims (75, 76, 77)
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Specification