Density modulated thin film electrodes, methods of making same, and applications of same

Patent metadata

Field	Value
Publication number	US-2016226065-A1
Application number	US-201615010628-A
Country	US
Kind code	A1
Filing date	Jan 29, 2016
Priority date	Jan 29, 2015
Publication date	Aug 4, 2016
Grant date	—

Abstract

Density modulated thin film electrodes, methods of making the same, and applications of the same. The density modulated thin film electrode includes a substrate formed of a current collecting material, and a thin film formed of an electrode material on the substrate. The thin film has a first surface and an opposite, second surface, and a density that is changed with a distance defined from the first surface to a plane in the thin film, the plane being parallel to the first surface. The method includes depositing the electrode material on the substrate to form the thin film, where, during deposition of the electrode material, a pressure of an operating gas is controlled and changed to a predetermined pressure value according to a deposited thickness of the electrode material, so as to make the density of the thin film changed with the distance.

First claim

What is claimed is:

1 . A thin film of an electrode material, comprising:
at least one layer formed of the electrode material, having a first surface and an opposite, second surface, and a density that is changed with a distance defined from the first surface to a plane in the at least one layer, the plane being parallel to the first surface, wherein the distance has a maximal value corresponding to a thickness of the at least one layer defined between the first and second surfaces.

2 . The thin film of claim 1 , wherein the electrode material comprises silicon (Si), carbon (C), graphite, titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), iron (Fe), nickel (Ni), copper (Cu), germanium (Ge), silicon-carbon composite/compound, tin (Sn), tin-cobalt alloy, lithium titanate (LTO, Li 4 Ti 5 O 12 ), cobalt oxide (CoO 2 ), nickel oxide (NiO 2 ), manganese oxide (MnO 2 ), titanium sulfide (TiS 2 , TiS 3 ), Li x FePO 4 , or the like.

3 . The thin film of claim 1 , wherein the density is gradually changed from a lowest density at one of the first and second surfaces to a highest density at the other of the first and second surfaces.

4 . The thin film of claim 1 , wherein the density is changed in the form of one or multiple periods of a sine wave function of the distance, or in the form of a rectangular function of the distance.

5 . The thin film of claim 1 , wherein the at least one layer of the electrode material comprises multiple layers of the electrode material formed such that layers having lower densities and layers having higher densities are alternately stacked to one another.

6 . A method for fabricating the thin film of the electrode material of claim 1 , comprising:
during deposition of the electrode material, controlling and changing a pressure of an operating gas to a predetermined pressure value according to a deposited thickness of the electrode material, so as to form the at least one layer of the electrode material having the density changed with the distance.

7 . The method of claim 6 , wherein the electrode material comprises silicon (Si), carbon (C), graphite, titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), iron (Fe), nickel (Ni), copper (Cu), germanium (Ge), silicon-carbon composite/compound, tin (Sn), tin-cobalt alloy, lithium titanate (LTO, Li 4 Ti 5 O 12 ), cobalt oxide (CoO 2 ), nickel oxide (NiO 2 ), manganese oxide (MnO 2 ), titanium sulfide (TiS 2 , TiS 3 ), Li x FePO 4 , or the like.

8 . The method of claim 6 , wherein the deposition of the electrode material is performed with a physical vapor deposition (PVD) comprising a sputter deposition, a thermal evaporation, an electron-beam evaporation, a cathodic arc deposition, a pulsed laser deposition (PLD), or the like.

9 . The method of claim 6 , wherein the operating gas comprises an inert gas or a reactive gas.

10 . An electrode usable for a battery, comprising:
a substrate formed of a current collecting material; and at least one layer formed of an electrode material on the substrate, the at least one layer having a first surface and an opposite, second surface, and a density that is changed with a distance defined from the first surface to a plane in the at least one layer, the plane being parallel to the first surface, wherein the distance has a maximal value corresponding to a thickness of the at least one layer defined between the first and second surfaces.

11 . The electrode of claim 10 , wherein the electrode material comprises silicon (Si), carbon (C), graphite, titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), iron (Fe), nickel (Ni), copper (Cu), germanium (Ge), silicon-carbon composite/compound, tin (Sn), tin-cobalt alloy, lithium titanate (LTO, Li 4 Ti 5 O 12 ), cobalt oxide (CoO 2 ), nickel oxide (NiO 2 ), manganese oxide (MnO 2 ), titanium sulfide (TiS 2 , TiS 3 ), Li x FePO 4 , or the like.

12 . The electrode of claim 10 , wherein the substrate comprises nanorod arrays formed of the current collecting material, such that the first surface of the at least one layer of the electrode material is substantially adhered to the substrate through the nanorod arrays.

13 . The electrode of claim 10 , wherein the current collecting material comprises copper (Cu), nickel (Ni), aluminum (Al), or the like.

14 . The electrode of claim 10 , further comprising an adhesion and compliant layer formed between the substrate and the at least one layer.

15 . The electrode of claim 14 , wherein the adhesion and compliant layer comprises nanorod arrays.

16 . The electrode of claim 14 , wherein the adhesion and compliant layer is formed of chromium (Cr), titanium (Ti), nickel (Ni), tantalum (Ta), molybdenum (Mo), tungsten (W), or the like.

17 . The electrode of claim 14 , wherein the adhesion and compliant layer is a graded composite layer of the current collecting material and the electrode material, formed by co-depositing the current collecting material and the electrode material with varying compositions as a function of thickness of the graded composite layer, wherein the graded composite layer has a first surface being substantially adhered to the substrate and an opposite, second surface being substantially adhered to the first surface of the at least one layer of the electrode material, and wherein ratio of the current collecting material to the electrode material of the graded composite layer is gradually changed from 100:0 at the first surface of the graded composite layer to 0:100 at the second surface of the graded composite layer by controlling their relative deposition rates.

18 . The electrode of claim 10 , wherein the density of the at least one layer of the electrode material is gradually changed from a lowest density at one of the first and second surfaces to a highest density at the other of the first and second surfaces.

19 . The electrode of claim 18 , further comprising a capping layer having a density higher than the lowest density, formed on the second surface of the at least one layer of the electrode material, when the density of the at least one layer of the electrode material at the second surface has the lowest density.

20 . The electrode of claim 10 , wherein the density of the at least one layer of the electrode material is changed in the form of one or multiple periods of a sine wave function of the distance, or in the form of a rectangular function of the distance.

21 . The electrode of claim 10 , wherein the at least one layer of the electrode material comprises multiple layers of the electrode material formed such that layers having lower densities and layers having higher densities are alternately stacked to one another.

22 . A method for fabricating the electrode of claim 11 , comprising:
providing the substrate formed of a current collecting material; and depositing the electrode material on the substrate to form the at least one layer, wherein, during deposition of the electrode material, a pressure of an operating gas is controlled and changed to a predetermined pressure value according to a deposited thickness of the electrode material, so that the at least one layer of the electrode material has the density changed with the distance.

23 . The method of claim 22 , wherein the electrode material comprises silicon (Si), carbon (C), graphite, titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), iron (Fe), nickel (Ni), copper (Cu), germanium

Assignees

• Univ Arkansas

Inventors

• Karabacak Tansel
• Demirkan Muhammed Taha

Classifications

• H01M4/387

  Tin or alloys based on tin · CPC title

• H01M4/386 Primary

  Silicon or alloys based on silicon · CPC title

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• H01M4/0426

  Sputtering · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title