Particle-based silicon electrodes for energy storage devices
Electrodes, energy storage devices using such electrodes, and associated methods are disclosed. In an example, an electrode for use in an energy storage device can comprise porous disks comprising a porous material, the porous disks having a plurality of channels and a surface, the plurality of channels opening to the surface; and a structural material encapsulating the porous disks; where the structural material provides structural stability to the electrode during use.
1. An electrode for use in an energy storage device comprising:
porous disks comprising a porous material, the porous disks having a plurality of channels and a surface, the plurality of channels opening to the surface, wherein the porous disks comprise multi-layered carbon-silicon with a carbon core; and
a structural material encapsulating the porous disks with a void space around the porous disks;
wherein the structural material provides structural stability to the electrode during use.
2. The electrode of claim 1 , wherein the porous disks have a thickness and have at least one dimension selected from length, width, or radius that is twice (2×) the thickness.
3. The electrode of claim 1 , further comprising an ion containing electrolyte, wherein the ion has a higher diffusion rate in the structural material than in the porous material.
4. The electrode of claim 3 , wherein the higher diffusion rate in the structural material is an order of magnitude higher than the diffusion rate in the porous material.
5. The electrode of claim 3 , wherein the ion containing electrolyte comprises a lithium salt including lithium hexafluorophosphate (LiPF 6 ), lithium hexafluoroarsenate monohydrate (LiAsF 6 ), lithium perchlorate (LiClO 4 ), lithium tetrafluoroborate (LiBF 4 ), lithium triflate (LiCF 3 SO 3 ), or mixtures thereof.
6. The electrode of claim 1 , wherein the structural materials have a specific charge storage capacity of from about 5% to about 50% of the specific capacity of the porous material.
7. The electrode of claim 1 , wherein the structural material is a carbon-based material.
8. The electrode of claim 7 , wherein the carbon-based material is selected from the group consisting of graphite, graphene, nanotubes, activated carbon, aerogels, and mixtures thereof.
9. The electrode of claim 1 , wherein the structural material is selected from the group consisting of germanium, tin, silicon carbide, titanium dioxide, and mixtures thereof.
10. The electrode of claim 1 , wherein the porous material is selected from the group of silicon, tin, germanium, SiGe, Si alloys, and titanium dioxide.
11. The electrode of claim 1 , wherein the porous material is silicon.
12. The electrode of claim 1 , further comprising a solid layer coated on the porous disks.
13. The electrode of claim 1 , wherein the porous particles have a porosity ranging from about 25% to about 80%.
14. An energy storage device comprising:
a first electrode comprising porous disks and an ion containing electrolyte, the porous disks embedded in a structural material with a void space around the porous disks, the porous disks comprising a porous material and having plurality of channels and a surface, the plurality of channels opening to the surface, wherein the porous disks comprise multi-layered carbon-silicon with a carbon core;
wherein the ion has a higher diffusion rate in the structural material than in the porous material.
15. The energy storage device of claim 14 , wherein the porous material is silicon.
16. The energy storage device of claim 14 , wherein the structural material is a carbon-based material selected from the group consisting of graphite, graphene, nanotubes, activated carbon, aerogels, and mixtures thereof.
17. The energy storage device of claim 14 , further comprising a second electrode wherein the first electrode is an anode.
18. A method of manufacturing an energy storage device, comprising:
providing a plurality of porous disks, the porous disks comprising a porous material, the porous material having a plurality of channels opening to a surface of the porous material, wherein the porous disks comprise multi-layered carbon-silicon with a carbon core;
embedding the porous disks within a structural material forming embedded porous disks with a void space around the porous disks;
diffusing an ion from an ion containing electrolyte into the porous material through the structural material;
wherein the embedded porous disks and a structural material form a first electrode and wherein the ion has a higher diffusion rate in the structural material than in the porous material.
19. The method of claim 18 , further comprising etching a material using an acidic solution to provide the porous material.
20. The method of claim 18 , wherein the porous material is selected from the group consisting of silicon, tin, germanium, SiGe, Si alloys, titanium dioxide, and mixtures thereof; and the structural material is selected from the group consisting of carbon, germanium, tin, silicon carbide, titanium oxide, and mixtures thereof.
21. The method of claim 18 , further comprising forming a solid layer on the surface of the porous material.
22. The method of claim 18 , wherein providing includes forming the porous disks by increasing porosity in discrete layers of a block of the porous material and subsequently breaking the discrete layers to form individual porous disks.