Template electrode structures for depositing active materials
Provided are examples of electrochemically active electrode materials, electrodes using such materials, and methods of manufacturing such electrodes. Electrochemically active electrode materials may include a high surface area template containing a metal silicide and a layer of high capacity active material deposited over the template. The template may serve as a mechanical support for the active material and/or an electrical conductor between the active material and, for example, a substrate. Due to the high surface area of the template, even a thin layer of the active material can provide sufficient active material loading and corresponding battery capacity. As such, a thickness of the layer may be maintained below the fracture threshold of the active material used and preserve its structural integrity during battery cycling.
1. An electrochemically active electrode material for use in a lithium ion cell, the electrochemically active electrode material comprising:
a nanostructured template comprising a metal silicide, the nanostructured template comprising nanowires rooted to a substrate, the nanowires comprising substrate-rooted ends and free ends;
a layer of a non-silicide electrochemically active material coating the nanowires, the non-silicide electrochemically active material having a theoretical lithiation capacity of at least about 500 mAh/g, wherein the layer of the non-silicide electrochemically active material is at least twice as thick at the free ends than at the substrate-rooted ends of the nanowires.
2. The electrochemically active electrode material of claim 1 , wherein the metal silicide is selected from a group consisting of nickel silicide, cobalt silicide, copper silicide, silver silicide, chromium silicide, titanium silicide, aluminum silicide, zinc silicide, and iron silicide.
3. The electrochemically active electrode material of claim 1 , wherein the non-silicide electrochemically active material is selected from the group consisting of crystalline silicon, amorphous silicon, silicon oxides, silicon oxy-nitrides, tin-containing material, and germanium-containing material.
4. The electrochemically active electrode material of claim 1 , further comprising a shell formed over the layer of the non-silicide electrochemically active material.
5. The electrochemically active electrode material of claim 4 , wherein the shell comprises one or more materials selected from the group consisting of carbon, copper, a polymer, a sulfide, lithium phosphorous oxynitride (LIPON), a metal oxide, and a fluorine containing compound.
6. The electrochemically active electrode material of claim 1 , wherein the substrate comprises a base, the base being substantially free of the metal of the metal silicide.
7. The electrochemically active material of claim 6 , wherein the substrate further comprises a layer of the metal of the metal silicide.
8. An electrochemically active electrode material for use in a lithium ion cell, the electrochemically active electrode material comprising:
a nanostructured template comprising a metal silicide; and
a non-silicide electrochemically active material shell coating the nanostructured template, the electrochemically active material having a theoretical lithiation capacity of at least about 500 mAh/g,
wherein the nanostructured template comprises nanowires rooted to a substrate, the nanowires having substrate-rooted ends and free-ends, wherein the metal silicide of the nanowires have a higher concentration of metal at the substrate-rooted ends than at the free-ends of the nanowires.
9. The electrochemically active electrode material of claim 8 , wherein the metal silicide is selected from a group consisting of nickel silicide, cobalt silicide, copper silicide, silver silicide, chromium silicide, titanium silicide, aluminum silicide, zinc silicide, and iron silicide.
10. The electrochemically active electrode material of claim 8 , wherein the electrochemically active material is selected from the group consisting of crystalline silicon, amorphous silicon, silicon oxides, silicon oxy-nitrides, tin-containing material, and germanium-containing material.
11. The electrochemically active electrode material of claim 8 , wherein the non-silicide electrochemically active material shell is disjoined at the substrate to form a plurality of disjoined electrochemically active material shells.
12. The electrochemically active electrode material of claim 8 , further comprising a second shell formed over the non-silicide electrochemically active material shell.
13. The electrochemically active electrode material of claim 12 , wherein the second shell comprises one or more materials selected from the group consisting of carbon, copper, a polymer, a sulfide, lithium phosphorous oxynitride (LIPON), a metal oxide, and a fluorine containing compound.