Separators for three-dimensional batteries

1. An electrode structure comprising a population of electrodes comprising an electrode active material layer and a population of counter-electrodes comprising a counter-electrode active material layer wherein

the population of electrodes is arranged in alternating sequence with the population of counter-electrodes along a first direction,

each member of the electrode population has a bottom, a top, a length L E , a width W E , a height H E , and a longitudinal axis A E extending from the bottom to the top of each such member and in a direction that is transverse to the first direction, the length L E of each member of the electrode population being measured in the direction of its longitudinal axis A E , the width W E of each member of the electrode population being measured in the first direction, and the height H E of each member of the electrode population being measured in a direction that is perpendicular to the longitudinal axis A E of each such member and the first direction, the ratio of L E to each of W E and H E of each member of the electrode population being at least 5:1, respectively, the ratio of H E to W E for each member of the electrode population being between 0.4:1 and 1000:1, respectively,

the longitudinal axis A E of each member of the population of electrodes is surrounded by an electrically insulating separator layer comprising a microporous separator material, such that the microporous separator material of the electrically insulating separator layer surrounds all surfaces of the member about the longitudinal axis A E , and

the microporous separator material comprises a particulate material and a binder, and has a void fraction of at least 20 vol %.

2. The electrode structure of claim 1 wherein between members of the electrode population and members of the counter-electrode population the microporous separator material constitutes at least 70 vol % of the electrically insulating separator material layer.

3. The electrode structure of claim 1 wherein the microporous separator material surrounds the longitudinal axis A E of each member of electrode population.

4. The electrode structure of claim 1 wherein the microporous separator material surrounds the longitudinal axis A E of each member of electrode population for at least 70% of the length L E of each member of the electrode population.

5. The electrode structure of claim 1 wherein the microporous separator material surrounds the longitudinal axis A E of each member of electrode population and the top of each member of the electrode population.

6. The electrode structure of claim 1 wherein the electrically insulating separator layer comprises the microporous separator material and a second electrically insulating material.

7. The electrode structure of claim 1 wherein each of the electrode and counter-electrode populations comprise at least 50 members.

8. The electrode structure of claim 1 wherein L E has a value in the range of about 10 mm and about 250 mm,

W E has a value in the range of about 0.01 mm and 2.5 mm, and

H E has a value in the range of about 0.05 mm to about 10 mm.

9. The electrode structure of claim 1 wherein the ratio of L E to each of W E and H E for each member of the electrode population is at least 10:1, respectively.

10. The electrode structure of claim 1 wherein a cross-section of each member of the electrode population has a perimeter P E and the ratio of L E to P E for each member of the electrode population is at least 1.25:1, respectively.

11. The electrode structure of claim 1 wherein each member of the counter-electrode population comprises a bottom, a top, a length L CE , a width W CE , a height H CE , and a longitudinal axis A CE extending from the bottom to the top of each such member and in a direction that is transverse to the first direction, the length L CE of each member of the electrode population being measured in the direction of its longitudinal axis A CE , the width W CE of each member of the electrode population being measured in the first direction, and the height H CE of each member of the electrode population being measured in a direction that is perpendicular to the longitudinal axis A CE of each such member and the first direction, the ratio of L CE to each of W CE and H CE of each member of the electrode population being at least 5:1, respectively, the ratio of H CE to W CE for each member of the electrode population being between 0.4:1 and 1000:1, respectively.

12. The electrode structure of claim 11 wherein L CE has a value in the range of about 10 mm and about 250 mm,

W CE has a value in the range of about 0.01 mm and 2.5 mm, and

H CE has a value in the range of about 0.05 mm to about 10 mm.

13. The electrode structure of claim 11 wherein the ratio of L CE to each of W CE and H CE for each member of the electrode population is at least 10:1, respectively.

14. The electrode structure of claim 1 wherein a cross-section of each member of the counter-electrode population has a perimeter P CE and the ratio of L CE to P CE for each member of the counter-electrode population is at least 1.25:1, respectively.

15. The electrode structure of claim 1 wherein each member of the population of electrodes further comprises an electrode backbone.

16. The electrode structure of claim 15 wherein for each member of the population of electrodes, the electrode current collector layer comprises an ionically permeable conductor material and is located between the electrode active material and the microporous separator material and the electrode active material is between the electrode current collector layer and the electrode backbone.

17. The electrode structure of claim 16 wherein for each member of the population of electrodes, the electrode current collector layer has an electrical conductance and an ionic conductance for carrier ions and the ratio of the electrical conductance of the electrode current collector layer to the ionic conductance of the electrode current collector layer for carrier ions is at least 1,000:1, respectively, when there is an applied current to store energy in the electrode structure or an applied load to discharge the electrode structure.

18. The electrode structure of claim 16 wherein the electrode current collector layer and the electrode active material layer have an electrical conductance and the ratio of the electrical conductance of the electrode current collector layer to the electrical conductance of the electrode active material layer is at least 100:1, respectively, for each member of the population of electrodes.

19. The electrode structure of claim 1 wherein each member of the population of electrodes further comprises a supplemental electrode current collector layer having a length that is at least 60% of the length L E-C of the electrode current collector layer comprised by each such member and a conductance that is at least 200% of the conductance of the electrode current collector layer comprised by each such member.

20. The electrode structure electrode of claim 1 wherein the electrode structure further comprises an electrode substrate having a surface to which each member of the electrode population is directly attached.

21. The electrode structure of claim 1 wherein the electrode structure further comprises an electrode substrate having a surface to which each member of the electrode population is directly attached and a counter-electrode substrate having a surface to which each member of the counter-electrode population is attached, the electrode substrate surface and the counter-electrode substrate surface being opposing surfaces that are substantially parallel to the first direction.

22. The electrode structure of claim 1 wherein the population of electrodes is a population of negative electrodes, the population of counter-electrodes is a population of positive electrodes, the electrode active material layer is a negative electrode active material layer and the electrode current conductor layer is a negative electrode current conductor layer.

23. The electrode structure of claim 22 wherein the negative electrode active material layer comprises carbon, aluminum, tin, silicon or an alloy thereof.

24. The electrode structure of claim 22 wherein the negative electrode active material layer comprises nanowires of silicon or an alloy thereof, or porous silicon or an alloy thereof.

25. The electrode structure of claim 1 wherein the population of electrodes is a population of negative electrodes, the population of counter-electrodes is a population of positive electrodes, each member of the population of negative electrodes comprises a negative electrode active material layer and a negative electrode current conductor layer, each member of the population of negative electrodes has a bottom, a top, a length L NE , a width W NE and a height H NE , the length L NE being measured from the bottom to the top of each such negative electrode, the width W NE and the height H NE being measured in directions that are perpendicular to each other and to the direction of measurement of the length L NE , the ratio of L NE to each of W NE and H NE being at least 5:1, respectively, the ratio of H NE to W NE being between 0.4:1 and 1000:1, the negative electrode current collector layer of each member of the population having a length L NC that is measured in the same direction as and is at least 50% of L NE .

26. The electrode structure of claim 1 wherein the population of electrodes is a population of positive electrodes, the population of counter-electrodes is a population of negative electrodes, each member of the population of positive electrodes comprises a positive electrode active material layer and a positive electrode current conductor layer, each member of the population of positive electrodes has a bottom, a top, a length L PE , a width W PE and a height H PE , the length L PE being measured from the bottom to the top of each such positive electrode, the width W PE and the height H PE being measured in directions that are perpendicular to each other and to the direction of measurement of the length L PE , the ratio of L PE to each of W PE and H PE being at least 5:1, respectively, the ratio of H PE to W PE being between 0.4:1 and 1000:1, respectively, the positive electrode current collector layer of each member of the positive population having a length Lpc that is measured in the same direction as and is at least 50% of L PE .

27. An electrode stack, the stack comprising at least two electrode structures, each of the electrode structures comprising an electrode structure of claim 1 .

28. The electrode stack of claim 27 wherein the electrode structures are stacked vertically whereby the populations of positive and negative electrodes comprised by a first electrode structure in the electrode stack lie in a different plane than the populations of positive and negative electrodes comprised by a second electrode structure in the electrode stack.

29. The electrode stack of claim 27 wherein the electrode structures are arranged horizontally whereby the populations of positive and negative electrodes comprised by a first electrode structure in the electrode stack lie in substantially the same plane as the populations of positive and negative electrodes comprised by a second electrode structure in the electrode stack.

30. A secondary battery comprising a battery enclosure, a non-aqueous electrolyte and an electrode structure of claim 1 .