Electrode structure for electrochemical cell
The present invention relates to the use of porous structures comprising electrode active materials, which can be used as electrodes in electrochemical cells. In certain embodiments, the electrodes described herein can comprise a first porous support structure (e.g., a plurality of particles, which can be porous in certain cases) in which electrode active material is at least partially contained. The first porous support structure can be, in some embodiments, at least partially contained within the pores of a second porous support structure (e.g., an agglomeration of elongated fibers, a porous web formed by sintered particles, etc.) containing pores that are larger than the components of the first porous support structure.
1. An electrode for use in an electrochemical cell comprising:
an assembly of electrically conductive elongated fibers wherein the elongated fibers comprise a metal, a polymer, and/or a glass;
an assembly of porous particles comprising carbon at least partially contained within the assembly of electrically conductive elongated fibers; and
an electrode active material comprising sulfur, wherein at least about 30 wt % of the electrode active material lies within pores of the porous particles.
2. The electrode of claim 1 , wherein the elongated fibers are at least partially coated with an electrically conductive material.
3. The electrode of claim 1 , wherein the electrode active material comprises elemental sulfur.
4. The electrode of claim 1 , wherein the electrode active material comprises particles having an average maximum cross-sectional dimension of between about 0.1 microns and about 10 microns.
5. The electrode of claim 1 , wherein the elongated fibers have an aspect ratio of at least about 3:1.
6. The electrode of claim 1 , wherein the elongated fibers have an aspect ratio of at least about 5:1.
7. The electrode of claim 1 , wherein the elongated fibers have an aspect ratio of at least about 10:1.
8. The electrode of claim 1 , wherein the assembly of electrically conductive elongated fibers forms a porous support structure in which at least about 50% of the total pore volume is defined by pores having cross-sectional diameters of at least about 10 micrometers.
9. The electrode of claim 1 , wherein the assembly of porous particles comprising carbon defines a porous support structure in which at least about 50% of the total pore volume is defined by pores having cross-sectional diameters of between about 0.1 micrometers and about 10 micrometers.
10. The electrode of claim 1 , wherein at least about 50% of a total pore volume within the electrode, in the absence of the electrode active material, is defined by pores having cross-sectional diameters of between about 0.1 micrometers and about 10 micrometers.
11. The electrode of claim 1 , wherein the assembly of electrically conductive elongated fibers forms a cohesive structure that can be bent, moved, or otherwise manipulated without falling apart.
12. An electrochemical cell comprising the electrode of claim 1 .
13. The electrochemical cell of claim 12 , wherein the electrochemical cell is a rechargeable electrochemical cell.
14. The electrochemical cell of claim 13 , wherein the electrochemical cell comprises a lithium-sulfur electrochemical cell.