Microstructured electrode structures

1. A structure for use in an energy storage device, the structure comprising a population of anode structures having a height, H A , of at least 50 micrometers measured in a direction orthogonal to a reference plane, each member of the population comprising a microstructured anodically active material layer having a front surface, a back surface, a thickness, T, measured from the front surface to the back surface, and a void volume fraction of at least 0.1, the front and back surfaces being substantially perpendicular to the reference plane, the thickness, T, being at least 1 micrometer and measured in a direction parallel to the reference plane, the microstructured anodically active material layers comprising a fibrous or a porous anodically active material oriented such that (i) anodically active material fibers comprised by the microstructured material layers are attached to the back surface of the layers and predominantly have central axes that are substantially parallel to the reference plane at the point of attachment of the fibers to the back surfaces of the microstructured anodically active material layers, and (ii) the pores of porous anodically active material comprised by the microstructured material layers predominantly have major axes that are substantially parallel to the reference plane wherein the lineal distance, D L , between at least two members of the population, measured in a direction parallel to the reference plane, is greater than the maximum value of H A for the population.

2. The structure of claim 1 wherein each member of the population comprises aluminum, tin, silicon or an alloy thereof.

3. The structure of claim 1 wherein each member of the population comprises nanowires of silicon or an alloy thereof, or porous silicon or an alloy thereof.

4. The structure of claim 1 wherein each member of the population comprises silicon or an alloy thereof and has a thickness of about 1 to about 100 micrometers.

5. The structure of claim 1 wherein for each member of the population H A is greater than T.

6. The structure of claim 1 wherein the microstructured anodically active material layer of each member of the population comprises porous silicon or an alloy thereof, has a void volume fraction of at least 0.1 but less than 0.8, and a thickness of about 1 to about 200 micrometers.

7. The structure of claim 1 wherein the each member of the population is supported by a backbone having an electrical conductivity of less than 10 Siemens/cm.

8. The structure of claim 1 wherein the maximum value of H A for the population is less than 5,000 micrometers.

9. The structure of claim 1 wherein the microstructured anodically active material layer of each member of the population comprises nanowires of silicon or an alloy thereof, or porous silicon or an alloy thereof, has a void volume fraction of at least 0.1 but less than 0.8, a thickness of about 1 to about 200 micrometers, and is supported by a backbone having an electrical conductivity of less than 10 Siemens/cm, and the maximum value of H A for the population is less than 5,000 micrometers.

10. The structure of claim 1 wherein the microstructured anodically active material layer of each member of the population comprises nanowires of silicon or an alloy thereof, or porous silicon or an alloy thereof, has a void volume fraction of at least 0.1 but less than 0.8, a thickness of about 1 to about 200 micrometers, and is supported by a backbone having an electrical conductivity of less than 1 Siemens/cm, and the maximum value of H A for the population is less than 1,000 micrometers.

11. The structure of claim 1 wherein the population comprises at least 20 members.

12. An electrochemical stack for use in an energy storage device, the electrochemical stack comprising, in a stacked arrangement, cathode structures, separator layers and a population of anode structures having a height, H A , of at least 50 micrometers measured in a direction orthogonal to a reference plane, the separator layers being disposed between the anode structures and the cathode structures, the direction of stacking of the cathode structures, the separator layers, and the anode structures being parallel to the reference plane, each member of the population of anode structures comprising a microstructured anodically active material layer having a front surface, a back surface, a thickness, T, measured from the front surface to the back surface, and a void volume fraction of at least 0.1, the front and back surfaces being substantially perpendicular to the reference plane, the thickness, T, being at least 1 micrometer and measured in a direction parallel to the reference plane, the microstructured anodically active material layers comprising a fibrous or a porous anodically active material oriented such that (i) anodically active material fibers comprised by the microstructured material layers are attached to the back surface of the layers and predominantly have central axes that are substantially parallel to the reference plane at the point of attachment of the fibers to the back surfaces of the microstructured anodically active material layers, and (ii) the pores of porous anodically active material comprised by the microstructured material layers predominantly have major axes that are substantially parallel to the reference plane wherein the lineal distance, D L , between at least two members of the population, measured in a direction parallel to the reference plane, is greater than the maximum value of H A for the population.

13. The electrochemical stack of claim 12 wherein the population comprises at least 20 members.

14. The electrochemical stack of claim 12 wherein each member of the population comprises nanowires of silicon or an alloy thereof, or porous silicon or an alloy thereof.

15. The electrochemical stack of claim 12 wherein each member of the population comprises silicon or an alloy thereof and has a thickness of about 1 to about 100 micrometers.

16. The electrochemical stack of claim 12 wherein for each member of the population H A is greater than T.

17. The electrochemical stack of claim 12 wherein each member of the population comprises porous silicon or an alloy thereof, has a void volume fraction of at least 0.1 but less than 0.8, and a thickness of about 1 to about 200 micrometers.

18. The electrochemical stack of claim 12 wherein each member of the population comprises nanowires of silicon or an alloy thereof, or porous silicon or an alloy thereof, has a void volume fraction of at least 0.1 but less than 0.8, a thickness of about 1 to about 200 micrometers, and is supported by a backbone and the maximum value of H A for the population is less than 5,000 micrometers.

19. The electrochemical stack of claim 12 wherein each member of the population comprises nanowires of silicon or an alloy thereof, or porous silicon or an alloy thereof, has a void volume fraction of at least 0.1 but less than 0.8, a thickness of about 1 to about 200 micrometers, and is supported by a backbone having an electrical conductivity of less than 10 Siemens/cm, and the maximum value of H A for the population is less than 1,000 micrometers.

20. The electrochemical stack of claim 12 wherein the anode structures comprise an anode current collector, the cathode structures comprise a cathode current collector, and the anode current collector or the cathode current collector comprises an ionically permeable conductor layer.

21. The electrochemical stack of claim 12 wherein the anode structures comprise an anode current collector layer and the anode current collector layer is disposed between and is in direct contact with an anodically active material layer and a separator layer.

22. The electrochemical stack of claim 21 wherein each member of the population comprises nanowires of silicon or an alloy thereof, or porous silicon or an alloy thereof, has a void volume fraction of at least 0.1 but less than 0.8, a thickness of about 1 to about 200 micrometers, and is supported by a backbone and the maximum value of H A for the population is less than 5,000 micrometers.

23. The electrochemical stack of claim 12 wherein the cathode structures comprise a cathode current collector layer and the cathode current collector layer is disposed between and is in direct contact with a cathodically active material layer and a separator layer.

24. An energy storage device comprising carrier ions, a non-aqueous electrolyte and an electrochemical stack, the carrier ions being lithium, sodium or potassium ions, the electrochemical stack comprising, in a stacked arrangement, cathode structures, separator layers and a population of anode structures having a height, H A , of at least 50 micrometers measured in a direction orthogonal to a reference plane, the separator layers being disposed between the anode structures and the cathode structures, the direction of stacking of the cathode structures, the separator layers, and the anode structures being parallel to the reference plane, each member of the population of anode structures comprising a microstructured anodically active material layer having a front surface, a back surface, a thickness, T, measured from the front surface to the back surface, and a void volume fraction of at least 0.1, the front and back surfaces being substantially perpendicular to the reference plane, the thickness, T, being at least 1 micrometer and measured in a direction parallel to the reference plane, the microstructured anodically active material layers comprising a fibrous or a porous anodically active material oriented such that (i) anodically active material fibers comprised by the microstructured material layers are attached to the back surface of the layers and predominantly have central axes that are substantially parallel to the reference plane at the point of attachment of the fibers to the back surfaces of the microstructured anodically active material layers, and (ii) the pores of porous anodically active material comprised by the microstructured material layers predominantly have major axes that are substantially parallel to the reference plane wherein the lineal distance, D L , between at least two members of the population, measured in a direction parallel to the reference plane, is greater than the maximum value of H A for the population.

25. The energy storage device of claim 24 wherein the carrier ions are lithium ions.

26. The energy storage device of claim 24 wherein the population comprises at least 20 members.

27. The energy storage device of claim 24 wherein each member of the population comprises silicon or an alloy thereof and has a thickness of about 1 to about 100 micrometers.

28. The energy storage device of claim 24 wherein for each member of the population H A is greater than T.

29. The energy storage device of claim 24 wherein each member of the population comprises nanowires of silicon or an alloy thereof, or porous silicon or an alloy thereof.

30. The energy storage device of claim 24 wherein each member of the population comprises porous silicon or an alloy thereof, has a void volume fraction of at least 0.1 but less than 0.8, and a thickness of about 1 to about 200 micrometers.

31. The energy storage device of claim 24 wherein each member of the population comprises nanowires of silicon or an alloy thereof, or porous silicon or an alloy thereof, has a void volume fraction of at least 0.1 but less than 0.8, a thickness of about 1 to about 200 micrometers, and is supported by a backbone and the maximum value of H A for the population is less than 5,000 micrometers.

32. The energy storage device of claim 24 wherein each member of the population comprises nanowires of silicon or an alloy thereof, or porous silicon or an alloy thereof, has a void volume fraction of at least 0.1 but less than 0.8, a thickness of about 1 to about 200 micrometers, and is supported by a backbone having an electrical conductivity of less than 10 Siemens/cm, and the maximum value of H A for the population is less than 1,000 micrometers.

33. The energy storage device of claim 24 wherein the anode structures comprise an anode current collector, the cathode structures comprise a cathode current collector, and the anode current collector or the cathode current collector comprises an ionically permeable conductor layer.

34. The energy storage device of claim 24 wherein the anode structures comprise an anode current collector layer and the anode current collector layer is disposed between and is in direct contact with an anodically active material layer and a separator layer.

35. The energy storage device of claim 34 wherein each member of the population comprises nanowires of silicon or an alloy thereof, or porous silicon or an alloy thereof, has a void volume fraction of at least 0.1 but less than 0.8, a thickness of about 1 to about 200 micrometers, and is supported by a backbone and the maximum value of H A for the population is less than 5,000 micrometers.

36. A secondary battery comprising carrier ions, a non-aqueous electrolyte and at least two electrochemical stacks, the carrier ions being lithium, sodium or potassium ions, each of the electrochemical stacks comprising, in a stacked arrangement, cathode structures, separator layers and a population of anode structures having a height, H A , of at least 50 micrometers measured in a direction orthogonal to a reference plane, the separator layers being disposed between the anode structures and the cathode structures, the direction of stacking of the cathode structures, the separator layers, and the anode structures within each such electrochemical stack being parallel to the reference plane, each member of the population of anode structures comprising a microstructured anodically active material layer having a front surface, a back surface, a thickness, T, measured from the front surface to the back surface, and a void volume fraction of at least 0.1, the front and back surfaces being substantially perpendicular to the reference plane, the thickness, T, being at least 1 micrometer and measured in a direction parallel to the reference plane, the microstructured anodically active material layers comprising a fibrous or a porous anodically active material oriented such that (i) anodically active material fibers comprised by the microstructured material layers are attached to the back surface of the layers and predominantly have central axes that are substantially parallel to the reference plane at the point of attachment of the fibers to the back surfaces of the microstructured anodically active material layers, and (ii) the pores of porous anodically active material comprised by the microstructured material layers predominantly have major axes that are substantially parallel to the reference plane wherein the electrochemical stacks are stacked relative to each other in a direction that is orthogonal to the reference plane.

37. The secondary battery of claim 36 wherein the carrier ions are lithium ions.

38. The secondary battery of claim 36 wherein the population comprises at least 20 members.

39. The secondary battery of claim 36 wherein each member of the population comprises nanowires of silicon or an alloy thereof, or porous silicon or an alloy thereof.

40. The secondary battery of claim 36 wherein each member of the population comprises silicon or an alloy thereof and has a thickness of about 1 to about 100 micrometers.

41. The secondary battery of claim 36 wherein for each member of the population H A is greater than T.

42. The secondary battery of claim 36 wherein each member of the population comprises porous silicon or an alloy thereof, has a void volume fraction of at least 0.1 but less than 0.8, and a thickness of about 1 to about 200 micrometers.

43. The secondary battery of claim 36 wherein each member of the population comprises nanowires of silicon or an alloy thereof, or porous silicon or an alloy thereof, has a void volume fraction of at least 0.1 but less than 0.8, a thickness of about 1 to about 200 micrometers, and is supported by a backbone and the maximum value of H A for the population is less than 5,000 micrometers.

44. The secondary battery of claim 36 wherein each member of the population comprises nanowires of silicon or an alloy thereof, or porous silicon or an alloy thereof, has a void volume fraction of at least 0.1 but less than 0.8, a thickness of about 1 to about 200 micrometers, and is supported by a backbone having an electrical conductivity of less than 10 Siemens/cm, and the maximum value of H A for the population is less than 1,000 micrometers.

45. The secondary battery of claim 36 wherein the anode structures comprise an anode current collector, the cathode structures comprise a cathode current collector, and the anode current collector or the cathode current collector comprises an ionically permeable conductor layer.

46. The secondary battery of claim 36 wherein the anode structures comprise an anode current collector layer and the anode current collector layer is disposed between and is in direct contact with an anodically active material layer and a separator layer.

47. The secondary battery of claim 36 wherein each member of the population comprises nanowires of silicon or an alloy thereof, or porous silicon or an alloy thereof, has a void volume fraction of at least 0.1 but less than 0.8, a thickness of about 1 to about 200 micrometers, and is supported by a backbone and the maximum value of H A for the population is less than 5,000 micrometers.

48. The structure of claim 1 wherein the microstructured anodically active material layers comprise mesoporous silicon or an alloy thereof, macroporous silicon or an alloy thereof or a combination of mesoporous and macroporous silicon or an alloy thereof, and the microstructured anodically active material layers have a thickness of about 2 to about 75 micrometers.

49. The structure of claim 1 wherein the lineal distance, D L , between at least two members of the population, measured in a direction parallel to the reference plane, is greater than the maximum value of H A for the population by a factor of at least 10.

50. The structure of claim 1 wherein the population comprises at least 50 members.

51. The structure of claim 1 wherein the anode structures are non-laminated and are supported by a base having a surface that is parallel to the reference plane, and the anode structures, cathode structures and separators have a surface area that exceeds the geometrical footprint of the supporting surface of the base by a factor of at least 2.

52. The structure of claim 1 wherein each of the anode structures comprise an anode backbone having a thickness of about 5 to about 50 micrometers, measured in the same direction as thickness T, and a height of about 50 to about 5,000 micrometers measured in the same direction as height H A .

53. The energy storage device of claim 24 wherein the microstructured anodically active material layers comprise mesoporous silicon or an alloy thereof, macroporous silicon or an alloy thereof or a combination of mesoporous and macroporous silicon or an alloy thereof, and the microstructured anodically active material layers have a thickness of about 2 to about 75 micrometers.

54. The energy storage device of claim 24 wherein the lineal distance, D L , between at least two members of the population, measured in a direction parallel to the reference plane, is greater than the maximum value of H A for the population by a factor of at least 10.

55. The energy storage device of claim 24 wherein the population comprises at least 50 members.

56. The energy storage device of claim 24 wherein the anode structures, cathode structures and separators are non-laminated and are supported by a base having a surface that is parallel to the reference plane, and the anode structures, cathode structures and separators have a surface area that exceeds the geometrical footprint of the supporting surface of the base by a factor of at least 2.

57. The energy storage device of claim 24 wherein each of the anode structures comprises an anode backbone having a thickness of about 5 to about 50 micrometers, measured in the same direction as thickness T, and a height of about 50 to about 5,000 micrometers measured in the same direction as height H A .