Methods of reducing occurrences of short circuits and/or lithium plating in batteries

1. A method of forming an electrode, the method comprising:

providing a current collector;

forming a safety layer on the current collector, the safety layer configured to reduce exposure of the current collector to an opposing electrode; and

forming an electrochemically active material film on the safety layer such that the safety layer extends over an area of the current collector that the electrochemically active material film extends over and beyond, and

pyrolyzing the electrochemically active material film to form a carbon phase that holds the film together.

2. The method of claim 1 , comprising adhering the electrochemically active material film to the current collector using the safety layer.

3. The method of claim 1 , wherein the electrochemically active material film comprises an anode film, and wherein the safety layer is configured to reduce exposure of the current collector to lithium deposition in a lithium ion battery.

4. The method of claim 1 , wherein the safety layer is in a substantially solid state.

5. The method of claim 1 , wherein the electrochemically active material film comprises silicon.

6. The method of claim 5 , wherein the electrochemically active material film comprises silicon at more than 30% by weight of the film.

7. The method of claim 6 , wherein the electrochemically active material film comprises silicon at more than 50% by weight of the film.

8. The method of claim 7 , wherein the electrochemically active material film comprises silicon at less than 90% by weight of the film.

9. The method of claim 1 , wherein the electrochemically active material film comprises a monolithic self-supporting film.

10. The method of claim 1 , wherein the electrochemically active material film comprises porosity that is substantially free of material forming the safety layer.

11. The method of claim 1 , wherein portions of the electrochemically active material film penetrate the safety layer and come in direct contact with the current collector.

12. The method of claim 1 , wherein the safety layer in the aggregate is substantially electrically nonconductive.

13. The method of claim 1 , wherein the safety layer is a substantially uniform layer.

14. The method of claim 1 , wherein the safety layer comprises a polymer.

15. The method of claim 14 , wherein the polymer comprises polyamideimide, polyvinylidene fluoride, or polyacrylic acid.

16. A method of forming an electrode, the method comprising:

providing a current collector;

forming a safety layer on the current collector, the safety layer configured to reduce exposure of the current collector to an opposing electrode; and

forming an electrochemically active material film on the safety layer, wherein the safety layer extends over an area of the current collector that the electrochemically active material film extends over and beyond, and wherein the electrochemically active material film comprises:

a carbon phase that holds the film together; and

silicon particles distributed within the carbon phase.

17. The method of claim 16 , comprising adhering the electrochemically active material film to the current collector using the safety layer.

18. The method of claim 16 , wherein the electrochemically active material film comprises an anode film, and wherein the safety layer is configured to reduce exposure of the current collector to lithium deposition in a lithium ion battery.

19. The method of claim 16 , wherein the safety layer is in a substantially solid state.

20. The method of claim 16 , wherein the electrochemically active material film comprises silicon.

21. The method of claim 20 , wherein the electrochemically active material film comprises silicon at more than 30% by weight of the film.

22. The method of claim 21 , wherein the electrochemically active material film comprises silicon at more than 50% by weight of the film.

23. The method of claim 22 , wherein the electrochemically active material film comprises silicon at less than 90% by weight of the film.

24. The method of claim 16 , wherein the electrochemically active material film comprises a monolithic self-supporting film.

25. The method of claim 16 , wherein the carbon phase comprises hard carbon.

26. The method of claim 16 , wherein the electrochemically active material film comprises porosity that is substantially free of material forming the safety layer.

27. The method of claim 16 , wherein portions of the electrochemically active material film penetrate the safety layer and come in direct contact with the current collector.

28. The method of claim 16 , wherein the safety layer in the aggregate is substantially electrically nonconductive.

29. The method of claim 16 , wherein the safety layer is a substantially uniform layer.

30. The method of claim 16 , wherein the safety layer comprises a polymer.

31. The method of claim 30 , wherein the polymer comprises polyamideimide, polyvinylidene fluoride, or polyacrylic acid.

32. A method of forming an electrode, the method comprising:

providing a current collector;

forming a safety layer on the current collector that is configured to reduce exposure of the current collector to an opposing electrode; and

forming an electrochemically active material film on the safety layer, wherein:

the safety layer extends over an area of the current collector that the electrochemically active material film extends over and beyond;

the electrochemically active material film comprises a carbon phase that holds the film together; and

the carbon phase comprises hard carbon.

33. The method of claim 32 , comprising adhering the electrochemically active material film to the current collector using the safety layer.

34. The method of claim 32 , wherein the electrochemically active material film comprises an anode film, and wherein the safety layer is configured to reduce exposure of the current collector to lithium deposition in a lithium ion battery.

35. The method of claim 32 , wherein the safety layer is in a substantially solid state.

36. The method of claim 32 , wherein the electrochemically active material film comprises silicon.

37. The method of claim 36 , wherein the electrochemically active material film comprises silicon at more than 30% by weight of the film.

38. The method of claim 37 , wherein the electrochemically active material film comprises silicon at more than 50% by weight of the film.

39. The method of claim 38 , wherein the electrochemically active material film comprises silicon at less than 90% by weight of the film.

40. The method of claim 32 , wherein the electrochemically active material film comprises a monolithic self-supporting film.

41. The method of claim 32 , wherein the electrochemically active material film comprises porosity that is substantially free of material forming the safety layer.

42. The method of claim 32 , wherein portions of the electrochemically active material film penetrate the safety layer and come in direct contact with the current collector.

43. The method of claim 32 , wherein the safety layer in the aggregate is substantially electrically nonconductive.

44. The method of claim 32 , wherein the safety layer is a substantially uniform layer.

45. The method of claim 32 , wherein the safety layer comprises a polymer.

46. The method of claim 45 , wherein the polymer comprises polyamideimide, polyvinylidene fluoride, or polyacrylic acid.

47. A method of forming an electrode, the method comprising:

providing a current collector;

forming a safety layer on the current collector that is configured to reduce exposure of the current collector to an opposing electrode; and

forming an electrochemically active material film on the safety layer, wherein:

the safety layer extends over an area of the current collector that the electrochemically active material film extends over and beyond; and

the electrochemically active material film comprises porosity that is substantially free of material forming the safety layer.

48. The method of claim 47 , comprising adhering the electrochemically active material film to the current collector using the safety layer.

49. The method of claim 47 , wherein the electrochemically active material film comprises an anode film, and wherein the safety layer is configured to reduce exposure of the current collector to lithium deposition in a lithium ion battery.

50. The method of claim 47 , wherein the safety layer is in a substantially solid state.

51. The method of claim 47 , wherein the electrochemically active material film comprises silicon.

52. The method of claim 51 , wherein the electrochemically active material film comprises silicon at more than 30% by weight of the film.

53. The method of claim 52 , wherein the electrochemically active material film comprises silicon at more than 50% by weight of the film.

54. The method of claim 53 , wherein the electrochemically active material film comprises silicon at less than 90% by weight of the film.

55. The method of claim 47 , wherein the electrochemically active material film comprises a monolithic self-supporting film.

56. The method of claim 47 , wherein portions of the electrochemically active material film penetrate the safety layer and come in direct contact with the current collector.

57. The method of claim 47 , wherein the safety layer in the aggregate is substantially electrically nonconductive.

58. The method of claim 47 , wherein the safety layer is a substantially uniform layer.

59. The method of claim 47 , wherein the safety layer comprises a polymer.

60. The method of claim 59 , wherein the polymer comprises polyamideimide, polyvinylidene fluoride, or polyacrylic acid.

61. A method of forming an electrode, the method comprising:

providing a current collector;

forming a safety layer on the current collector that is configured to reduce exposure of the current collector to an opposing electrode; and

forming an electrochemically active material film on the safety layer, wherein:

the safety layer extends over an area of the current collector that the electrochemically active material film extends over and beyond; and

the safety layer in the aggregate is substantially electrically nonconductive.

62. The method of claim 61 , comprising adhering the electrochemically active material film to the current collector using the safety layer.

63. The method of claim 61 , wherein the electrochemically active material film comprises an anode film, and wherein the safety layer is configured to reduce exposure of the current collector to lithium deposition in a lithium ion battery.

64. The method of claim 61 , wherein the safety layer is in a substantially solid state.

65. The method of claim 61 , wherein the electrochemically active material film comprises silicon.

66. The method of claim 65 , wherein the electrochemically active material film comprises silicon at more than 30% by weight of the film.

67. The method of claim 66 , wherein the electrochemically active material film comprises silicon at more than 50% by weight of the film.

68. The method of claim 67 , wherein the electrochemically active material film comprises silicon at less than 90% by weight of the film.

69. The method of claim 61 , wherein the electrochemically active material film comprises a monolithic self-supporting film.

70. The method of claim 61 , wherein portions of the electrochemically active material film penetrate the safety layer and come in direct contact with the current collector.

71. The method of claim 61 , wherein the safety layer is a substantially uniform layer.

72. The method of claim 61 , wherein the safety layer comprises a polymer.

73. The method of claim 72 , wherein the polymer comprises polyamideimide, polyvinylidene fluoride, or polyacrylic acid.