Electrochemical systems with at least one electronically and ionically conductive layer
Electrochemical systems with electronically and ionically conductive layers have electronic, mechanical and chemical properties useful for a variety of applications including electrochemical storage and conversion. Electronically and ionically conductive layers may be introduced between an electrode and the separator. 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 and may 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. An electronically and ionically conductive layer may provide electronic conductivity greater than or equal to 1 S/cm and ionic resistance less than or equal to 10 Ωcm 2 .
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 an electronically conductive polymer or an electronically conductive ceramic; 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 Ωcm 2 .
2. The electrochemical cell of claim 1 , wherein said first electronically and ionically conductive layer comprises a porous layer, a perforated layer, or a mesh.
3. The electrochemical cell of claim 1 , wherein said first electronically and ionically conductive layer conducts ions via transport of said charge carriers of said electrolyte through one or more apertures or pores in said first electronically and ionically conductive layer.
4. The electrochemical cell of claim 1 , wherein said first electronically and ionically conductive layer has a porosity greater than or equal to 30%.
5. The electrochemical cell of claim 1 , wherein said first electronically and ionically conductive layer has a porosity selected from the range of 30% to 90%.
6. The electrochemical cell of claim 1 , wherein said first electronically and ionically conductive layer has a thickness less than or equal to 100 μm.
7. The electrochemical cell of claim 1 , wherein said first electronically and ionically conductive layer has a thickness selected from the range of 10 nm to 100 μm.
8. The electrochemical cell of claim 1 , wherein said first electronically and ionically conductive layer comprises a thin film structure or coating.
9. The electrochemical cell of claim 8 , wherein said thin film structure or coating is deposited on at least one external surface of said positive electrode.
10. The electrochemical cell of claim 8 , wherein said thin film structure or coating is deposited on at least one external surface of said negative electrode.
11. The electrochemical cell of claim 8 , wherein said thin film structure or coating is deposited on at least one external surface of said separator.
12. The electrochemical cell of claim 1 , wherein said first electronically and ionically conductive layer is provided in physical contact with said separator.
13. 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.
14. 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.
15. The electrochemical cell of claim 14 , 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.
16. The electrochemical cell of claim 14 , 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.
17. The electrochemical cell of claim 1 , wherein said first electronically and ionically conductive layer comprises poly(fluorene), polyphenylene, polypyrene, polyazulene, polynaphthalene, poly(acetylene), poly(p-phenylene vinylene), poly(pyrrole), polycarbazole, polyindole, polyazepine, polyaniline, poly(thiophene), poly(3,4-ethylenedioxythiophene), poly(p-phenylene sulfide), polyfluorene-based conducting polymer, polyacrylonitrile, poly(9,9-dioctylfluorene-co-fluorenone), poly(9,9-dioctylefluorene-co-fluorenone-co-methylbenzoic ester), polythiophene, polypyrrole, poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) [(ferocenyl)amidopropyl]pyrrole, pyrrole, polypyrrole, polyaniline, polythiophene, polyfuran, Na 2 PO 2 N, or polyvinyl chloride or doped compositions thereof.
18. The electrochemical cell of claim 1 , wherein said first electronically and ionically conductive layer comprises indium tin oxide, lanthanum-doped strontium titanate, or yttrium-doped strontium titanate.
19. The electrochemical cell of claim 1 , 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.
20. 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.
21. 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.
22. 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.
23. 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.
24. 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, or an electrochemical capacitor.
25. The electrochemical cell of claim 1 , wherein said electrochemical cell comprises 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 or a lead acid battery.