Electrochemical methods, devices, and structures

• US 20080157713A1
• Filed: 04/26/2007
• Published: 07/03/2008
• Est. Priority Date: 06/14/2004
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Chiang, Yet-Ming, Chin, Timothy E., Song, Kyungyeol, Hall, Steven R., Baetz, Georg, Kuri, Fernando Tubilla
• Granted Patent: US 7,994,686 B2
• Time in Patent Office: Days
• US Class Current: 320/103
• CPC Class Codes: F03G 7/005 Electro-chemical actuators; Actuators having a material for absorbing or desorbing gas, e.g. a metal hydride; Actuators using the difference in osmotic pressure between fluids; Actuators with elements stretchable when contacted with liquid rich in ions, with UV light, with a salt solution
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 2010/4292 Aspects relating to capacity ratio of electrodes/electrolyte or anode/cathode
• CPC Class Codes: H01M 4/485 of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy H01M4/505, H01M4/525 take precedence
• CPC Class Codes: H01M 4/505 of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: H01M 50/409 Separators, membranes or diaphragms characterised by the material
• CPC Class Codes: H01M 6/30 Deferred-action cells
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The present invention generally provides devices and methods involving electrochemical actuation. The devices may comprise at least one component capable of exhibiting a volumetric or dimensional change upon application of a voltage. In some cases, the volumetric or dimensional change may produce mechanical work. Some embodiments of the invention may provide devices capable of exhibiting high actuation rates and supporting high amounts of stress (e.g., in tensile and/or compressive loading). In some embodiments, the present invention may provide morphing structures that may be useful in applications such as airfoils.

Claims

1. An article, comprising:

at least one electrochemical cell comprising an anode, a cathode, and an intercalation species, wherein the electrochemical cell undergoes a volumetric or dimensional change upon the application of a voltage or current; and

a structure including at least one portion constructed and arranged to be displaced from a first orientation to a second orientation so as to impart a different fluid dynamic property to the structure by the volumetric or dimensional change of the at least one electrochemical cell.

2. An article as in claim 1, wherein the structure is an airfoil.

3. An article as in claim 1, wherein the structure is a hull.

4. An article as in claim 1, wherein the structure is a fuselage.

5. An article as in claim 1, wherein the structure is a hydrofoil.

6. An article as in claim 1, wherein the fluid dynamic property is an aerodynamic property.

7. An article as in claim 1, wherein the at least one portion is displaced by a hinge.

8. An article as in claim 1, wherein the at least one portion is not displaced by a hinge.

9. An article as in claim 1, the at least one portion is displaced without movement of immediately adjacent macroscopic portions of the structure relative to one another.

10. A method, comprising:

operating an electrochemical cell comprising a negative electrode, a positive electrode, a nonaqueous electrolyte, and lithium as an intercalation species,

wherein the positive electrode has an average equilibrium potential with respect to metallic lithium over the state of charge of its use that is less than about +4V, and the negative electrode has an average equilibrium potential with respect to metallic lithium over the state of charge of its use that is greater than about +0.2V,

wherein the electrochemical cell is in operative relationship with a component that can be displaced from a first orientation to a second orientation, and

wherein operation of the electrochemical cell causes a volumetric or dimensional change of the electrochemical cell.

11. A method as in claim 10, wherein the positive electrode has an average equilibrium potential of less than about +3.5V, and the negative electrode has an average equilibrium potential of greater than about +0.5V.

12. A method as in claim 10, wherein the positive electrode has an average equilibrium potential of less than about +3.5V, and the negative electrode has an average equilibrium potential of greater than about +1.0V.

13. A method as in claim 10, wherein the positive electrode has an average equilibrium potential of less than about +3.5V, and the negative electrode has an average equilibrium potential of greater than about +1.5V.

14. A method as in claim 10, wherein the positive electrode has an average equilibrium potential of less than about +3.0V, and the negative electrode has an average equilibrium potential of greater than about +0.5V.

15. A method as in claim 10, further comprising applying a voltage of less than about 10V to the electrochemical cell and, from the volumetric or dimensional change of the electrochemical cell, displacing the component from the first orientation to the second orientation.

16. A method as in claim 15, comprising applying a voltage of less than about 7.5V to the electrochemical cell and, from the volumetric or dimensional change of the electrochemical cell, displacing the component from a first orientation to a second orientation.

17. A method as in claim 15, comprising applying a voltage of less than about 5V to the electrochemical cell and, from the volumetric or dimensional change of the electrochemical cell, displacing the component from a first orientation to a second orientation.

18. A method as in claim 15, comprising applying a voltage of less than about 4V to the electrochemical cell and, from the volumetric or dimensional change of the electrochemical cell, displacing the component from a first orientation to a second orientation.

19. A method as in claim 10, wherein the component is a portion of an airfoil.

20. A method as in claim 10, wherein the component is a portion of a hull.

21. A method as in claim 10, wherein the component is a portion of a fuselage.

22. A method as in claim 10, wherein the component is a portion of a hydrofoil.

23. A method as in claim 10, wherein displacement comprises movement by a hinge.

24. A method as in claim 10, wherein displacement does not comprise movement by a hinge.

25. A method as in claim 10, wherein displacing the component from a first orientation to a second orientation occurs without movement of immediately adjacent macroscopic portions of the component relative to one another.

26. An article, comprising:

a first and a second electrochemical cell configured in an antagonistic arrangement relative to one another, such that discharge of the first cell results in charging of the second cell, and discharge of the second cell results in charging of the first cell; and

a component constructed and arranged to be displaced from a first orientation to a second orientation by charge and/or discharge of at least one of the first and second electrochemical cells.

27. An article method as in claim 26, wherein the component is a portion of an airfoil.

28. An article as in claim 26, wherein the component is a portion of a hull.

29. An article as in claim 26, wherein the component is a portion of a fuselage.

30. An article as in claim 26, wherein the component is a portion of a hydrofoil.

31. An article, comprising:

an electrochemical cell comprising an anode comprised of a first material and a cathode comprised of a second material, wherein the anode and cathode are constructed and arranged such that during a cycle in which one of the electrodes expands at least 1% by volume, the other electrode does not substantially contract; and

a component constructed and arranged to be displaced from a first orientation to a second orientation by charge and/or discharge of the electrochemical cell.

32. An article as in claim 31, wherein the electrochemical cell is operated at a cathode potential of less than 4 V with respect to the potential of metallic lithium.

33. An article as in claim 31, wherein the electrochemical cell is operated at an anode potential of greater than 0.5 V with respect to the potential of metallic lithium

34. An article as in claim 31, wherein the first material comprises Li_xTiO₂ of a spinel structure or any alloy or doped composition thereof.

35. An article as in claim 31, wherein the second material comprises Li_xTiS₂ or Li_xTaS₂, or any alloy or doped composition thereof.

36. An article as in claim 31, wherein the second material comprises LiMPO₄, where M is one or more first-row transition metals, or any alloy or doped composition thereof.

37. An inorganic structure constructed and arranged to be actuated during use from a first orientation to a second orientation providing different aerodynamic effects in the first and second orientations, wherein the structure is actuated by an electrochemical actuator without movement of immediately adjacent macroscopic components of the structure relative to one another.

38. An inorganic structure as in claim 37, wherein the structure is an airfoil.

39. An inorganic structure as in claim 37, wherein the structure is a hull or fuselage.