Electrochemical systems with electronically conductive layers

Patent metadata

Field	Value
Publication number	US-9379368-B2
Application number	US-201313738835-A
Country	US
Kind code	B2
Filing date	Jan 10, 2013
Priority date	Jul 11, 2011
Publication date	Jun 28, 2016
Grant date	Jun 28, 2016

Abstract

Provided are electrochemical systems with electronically and ionically conductive layers that have electronic, mechanical and chemical properties useful for a variety of applications including electrochemical storage and conversion. State of the art electrochemical cells are made with electronically non-conductive separators between the opposite electrodes as the natural choice to prevent any electronic path between the opposite electrodes. Herein, electronically conductive layers are introduced between an electrode and the separator without producing any direct electronic path between the opposite electrodes. Embodiments provide structural, physical and electrostatic attributes useful for managing and controlling dendrite formation and for improving the cycle life and rate capability of electrochemical cells including silicon anode based batteries, air cathode based batteries, redox flow batteries, solid electrolyte based systems, fuel cells, flow batteries and semisolid batteries. Disclosed electronically and ionically conductive layers include multilayer, porous geometries supporting excellent ion transport properties, providing a barrier to prevent dendrite initiated mechanical failure, shorting or thermal runaway, or providing improved electrode conductivity and improved electric field uniformity. Disclosed electronically and ionically conductive layers between the separator and an electrode include metals, metal alloys, a carbon materials, semiconductors, electronically conductive polymers, electronically conductive ceramics and any combination of these.

First claim

I claim:

1. An electrochemical cell comprising:
a positive electrode;
a negative electrode;
an ionically conductive and electronically insulating separator positioned between said positive electrode and said negative electrode;
a first electronically and ionically conductive layer positioned between said positive electrode and said separator and in electrical contact with said positive electrode or positioned between said negative electrode and said separator and in electrical contact with said negative electrode wherein said first electronically and ionically conductive layer comprises a porous, perforated or foam material having a porosity greater than or equal to 30%, has a thickness selected from the range of 10 nm to 100 μm, and comprises a metal, a metal alloy, a carbon material, a semiconductor, or any combination of these; and
one or more electrolytes positioned between said positive electrode and said negative electrode; wherein said one or more electrolytes are capable of conducting charge carriers; wherein said first electronically and ionically conductive layer provides an electronic conductivity greater than or equal to 1 S/cm and provides an ionic resistance less than or equal to 10 Ω·cm 2 .

2. The electrochemical cell of claim 1 , wherein said first electronically and ionically conductive layer comprises a metallic or alloy mesh, a metallic or alloy perforated layer, a metal or alloy coating, or a carbon coating.

3. The electrochemical cell of claim 1 , wherein said first electronically and ionically conductive layer comprises a thin film structure deposited on at least one external surface of said separator, said positive electrode or said negative electrode or a coating coated on at least one external surface of said separator, said positive electrode or said negative electrode.

4. The electrochemical cell of claim 1 , wherein at least a portion of said first electronically and ionically conductive layer is positioned within an active material of said positive electrode or within an active material of said negative electrode; wherein said portion of said first electronically and ionically conductive layer that is positioned within said active material of said positive electrode or said active material of said negative electrode is not in physical contact with said separator, or wherein said portion of said first electronically and ionically conductive layer that is positioned within said active material of said positive electrode or said active material of said negative electrode is in physical contact with a current collector of said positive electrode or a current collector of said negative electrode, or wherein said portion of said first electronically and ionically conductive layer that is positioned within said active material of said positive electrode or said active material of said negative electrode is not in physical contact with a said current collector of said positive electrode or a said current collector of said negative electrode.

5. The electrochemical cell of claim 4 , wherein said portion of said first electronically and ionically conductive layer that is positioned within said active material of said positive electrode or said active material of said negative electrode is provided within said active material of said positive electrode or said active material of said negative by a method selected from the group consisting of wet processing, dry processing, mechanical pressing, thermal deposition, coating and any combination of these.

6. The electrochemical cell of claim 1 , wherein said first electronically and ionically conductive layer is provided in physical contact with said separator.

7. The electrochemical cell of claim 1 , wherein said first electronically and ionically conductive layer is in physical contact with said positive electrode or said negative electrode.

8. The electrochemical cell of claim 1 , wherein said first electronically and ionically conductive layer provides an added path for electron transfer between said positive electrode and a positive electrode current collector or an added path for electron transfer between said negative electrode and a negative electrode current collector or wherein said first electronically and ionically conductive layer increases an electronic conductivity of at least a portion of said negative electrode or said positive electrode.

9. The electrochemical cell of claim 1 , further comprising a second electronically and ionically conductive layer; wherein said first electronically and ionically conductive layer is positioned in electrical contact with said positive electrode and wherein said second electronically and ionically conductive layer is positioned in electrical contact with said negative electrode, and wherein said first and second electronically and ionically conductive layers are not in physical or electrical contact with each other.

10. The electrochemical cell of claim 1 , wherein said first electronically and ionically conductive layer provides a homogeneous electric field adjacent to and within said positive electrode or said negative electrode, thereby providing uniform ion deposition into said positive electrode or said negative electrode; or wherein said first electronically and ionically conductive layer prevents dendrite growth on or from said positive electrode or said negative electrode.

11. The electrochemical cell of claim 1 , wherein said separator comprises a microporous layer comprising a polymer, polyethylene, polypropylene, polyethylene terephthalate, poly(4,4′-oxydiphenylene-pyromellitimide), polytetrofluoroethylene, glass separator, nonwoven separator, woven separator, a polymer electrolyte, a solid electrolyte, a gel electrolyte, C 7 HF 13 O 5 S.C 2 F 4 Nafion, ZrO 2 , polyvinylidene difluoride, polyethylene oxide, poly(methyl methacrylate), Li 2+2x Zn 1−x GeO, Na 1+x Zr 2 Si x P 3−x O 12 , 0<x<3, Li 2 PO 2 N, Na 2 PO 2 N, or any combination of these.

12. The electrochemical cell of claim 1 , wherein said separator comprises a coating coated on at least one external surface of said first electronically and ionically conductive layer, at least one surface of said positive electrode or at least one surface of said negative electrode or wherein said separator comprises a thin film deposited on at least one external surface of said first electronically and ionically conductive layer, at least one surface of said positive electrode or at least one surface of said negative electrode.

13. The electrochemical cell of claim 1 , wherein said first electronically and ionically conductive layer is a coating on said separator; and wherein said separator has a total thickness less than or equal to 500 μm.

14. The electrochemical cell of claim 1 , wherein said first electronically and ionically conductive layer comprises an external current collector pole; or wherein said first electronically and ionically conductive layer reduces one of said positive electrode and said negative electrode; or wherein said external current collector pole oxidizes one of said positive electrode and said negative electrode.

15. The electrochemical cell of claim 1 , wherein said electrochemical cell comprises a secondary battery, a primary battery, a flow battery, a semi-solid battery, a fuel cell, an electrochemical capacitor, a lead acid battery, a lithium ion battery, a lithium metal battery, a zinc battery, a lithium-air battery, a zinc-air battery, an aluminum-air battery, an iron-air battery, a lithium-water battery, a silicon based battery, a sodium battery, a magnesium battery, a sodium ion battery, a magnesium ion battery, an alkaline battery o

Assignees

• California Inst Of Techn

Inventors

• Roumi Farshid

Classifications

• H01M50/431

  Inorganic material · CPC title

• H01M50/449 Primary

  having a layered structure · CPC title

• H01M50/494

  Tensile strength · CPC title

• H01M50/457

  comprising three or more layers · CPC title

• H01M50/491

  Porosity · CPC title