SOLUTION-PHASE ELECTRODEPOSITION OF ARTIFICIAL SOLID ELECTROLYTE INTERPHASE (SEI) LAYERS ON BATTERY ELECTRODES

Abstract

Methods, systems, and related aspects for solution -phase electrodeposition of artificial solid- electrolyte interphase (SEI) layers coated onto battery electrodes. In certain aspects, such a method comprises: (a) providing the battery electrode onto a conveyance apparatus; (b) transferring, by the conveyance apparatus, the battery electrode to an electrodeposition chamber containing a liquid solution comprising a first reagent and an electrolyte; exposing the battery electrode to the liquid solution; and applying a voltage or current to the battery electrode relative to a counter electrode exposed to the liquid solution for a predetermined amount of time, thereby yielding a coated battery electrode comprising the artificial SEI.

Claims

1. A method for electrodepositing an artificial solid-electrolyte interphase (“SEI”) coating onto the surface of a battery electrode to produce a coated battery electrode, the method comprising: (a) providing the battery electrode onto a conveyance apparatus; (b) transferring, by the conveyance apparatus, the battery electrode to an electrodeposition chamber containing a liquid solution comprising an at least first reagent; (c) exposing the battery electrode to the liquid solution in the electrodeposition chamber; and (d) applying a voltage or current to the battery electrode relative to a counter electrode exposed to the liquid solution for a predetermined amount of time, thereby yielding the coated. battery electrode comprising the artificial SEI coating.

2. The method of claim 1, wherein: the artificial SEI coating has a thickness from about 0.5 nm to 100 μm, the battery electrode in (a) has a thickness of 100 nm to 1,000 μm, the battery electrode in (a) has pores ranging in size of 0.1 nm to 100 μm, and the battery electrode in (a) has a film porosity of 1-99%,

3-5. (canceled)

6. The method of any of the preceding claims claim 1, wherein the battery electrode in (a) is composed of graphite, Si, Sn, Ge, Al, P, Zn, Ga, As, Cd, In, Sb, Pb, Bi, SiO, SnO.sub.2, a Si-graphite composite, a Sn-graphite composite or lithium metal.

7. The method of claim 1, wherein the battery electrode in (a) is composed of LiNi.sub.xMn.sub.yCo.sub.zO.sub.2, LiNi.sub.xCo.sub.yAl.sub.zO.sub.2, LiMn.sub.xNi.sub.yO.sub.z, LiMnO.sub.2, LiFePO.sub.4, LiMnPO.sub.4, LiNiPO.sub.4, LiCoPO.sub.4, LiV.sub.2O.sub.5, sulfur or LiCoO.sub.2 where x, y and z are stoichiometric coefficients.

8. The method of claim 1, wherein the conveyance apparatus comprises a series of rollers for guiding the battery electrode into the electrodeposition chamber.

9. (canceled)

10. The method of claim 1, wherein the battery electrode is composed of an active material that is deposited on a continuous substrate.

11-14. (canceled)

15. The method of claim 10, wherein the substrate is made up of an organic material selected from the group consisting of polyimide, polyethylene, polyether ether ketone (PEEK), polyester, and polyethylene napthalate (PEN).

16. The method of claim 10, wherein the substrate is made up of a metal comprising at least one of copper, aluminum, or stainless steel.

17. (canceled)

18. (canceled)

19. The method of claim 1, further comprising: rinsing the coated battery electrode post-deposition with a rinsing solution comprising at least a solvent; and exposing the coated battery electrode to a thermal treatment in the presence of an ambient gas mixture, wherein the ambient gas mixture comprises at least one of O.sub.2, ozone, N.sub.2, or Ar.

20. (canceled)

21. (canceled)

22. The method of claim 19, wherein the coated battery electrode is heated to temperatures up to 300 degrees Celsius.

23. The method of claim 1, further comprising exposing the coated battery electrode to a thermal treatment in the presence of gases or a plasma prior to artificial SEI coating via electrodeposition, wherein the plasma comprises at least one of oxygen, argon, hydrogen, or nitrogen.

24. (canceled)

25. (canceled)

26. The method of claim 1, wherein: the liquid solution comprises an electrolyte, the electrolyte comprises a solvent and a salt the solvent comprises an organic solvent, an ionic liquid water, or a mixture of these, and the salt comprises a lithium-containing; compound.

27. (canceled)

28. The method of claim 26, wherein the lithium-containing compound is LiClO.sub.4.

29. (canceled)

30. The method of claim 26, wherein the electrolyte comprises a solvent and artificial SEI forming reactants.

31. The method of claim 1, wherein artificial SEI coating comprises a compound selected from one of the following groups: (a) binary oxides of type A.sub.xO.sub.y, where A is an alkali metal, alkali-earth metal, transition metal, semi metal or metalloid and x and y are stoichiometric coefficients; (b) ternary oxides of type A.sub.xB.sub.yO.sub.z, where A and B are any combination of alkali metal, alkali-earth metal, transition metal, semimetal or metalloid and x, y and z are stoichiometric coefficients: (c) quaternary oxides of type A.sub.wB.sub.xC.sub.yO.sub.z where A, B and C are any combination of alkali metal, alkali-earth metal, transition metal, semimetal or metalloid and w, x, y and z are stoichiometric coefficients; (d) binary halides of type A.sub.xB.sub.y, where A is an alkali metal, alkali-earth metal, transition metal, semimetal or metalloid, B is a halogen and x and y are stoichiometric coefficients; (e) ternary halides of type A.sub.xB.sub.yC.sub.z, where A and B are any combination of alkali metal, alkali-earth metal, transition metal, semimetal or metalloid, C is a halogen and x, y and z are stoichiometric coefficients; (f) quaternary halides of type A.sub.wB.sub.xC.sub.yD.sub.z, where A, B and C are any combination of alkali metal, alkali-earth metal, transition metal, semimetal or metalloid, D is a halogen and w, x, y and z are stoichiometric coefficients; (g) binary nitrides of type A.sub.xN.sub.y, where A is an alkali metal, alkali-earth metal, transition metal, semimetal or metalloid and x and y are stoichiometric coefficients; (h) ternary nitrides of type A.sub.xB.sub.yN.sub.z, where A and B are any combination of alkali metal, alkali-earth metal, transition metal, semimetal or metalloid and x, y and z are stoichiometric coefficients; (i) quaternary nitrides of type A.sub.wB.sub.xC.sub.yN.sub.z, where A, B and C are any combination of alkali metal, alkali-earth metal, transition metal, semimetal or metalloid and w, x, y and z are stoichiometric coefficients: (j) binary chalcogenides of type A.sub.xB.sub.y, where A is an alkali metal, alkali-earth metal, transition metal, semimetal or metalloid, B is a chalcogen and x and y are stoichiometric coefficients, (k) ternary chalcogenides of type A.sub.xB.sub.yC.sub.z, where A and B are any combination of alkali metal, alkali-earth metal, transition metal, semimetal or metalloid, C is a chalcogen and x, v and z are stoichiometric coefficients; (l) quaternary chalcogenides of type A.sub.wB.sub.xC.sub.yD.sub.z, where A, B and C are any combination of alkali metal, alkali-earth metal, transition metal, semimetal or metalloid, B is a chalcogen and w, x, y and z are stoichiometric coefficients; (m) binary carbides of type A.sub.xC.sub.y, where A is an alkali metal, alkali-earth metal, transition metal, semimetal or metalloid and x and y are stoichiometric coefficients; (n) binary oxyhalides of type A.sub.xB.sub.yO.sub.z, where A is an alkali metal, alkali-earth metal, transition metal, semimetal or metalloid, B is a halogen and x, y and z are stoichiometric coefficients; (o) binary arsenides of type A.sub.xAs.sub.y, where A is an alkali metal, alkali-earth metal, transition metal, semimetal or metalloid and x and y are stoichiometric coefficients; (p) ternary- arsenides of type A.sub.xB.sub.yAs.sub.z, where A and B are any combination of alkali metal, alkali-earth metal, transition metal, semimetal or metalloid and x, y and z are stoichiometric coefficients: (q) quaternary arsenides of type A.sub.wB.sub.xC.sub.yAs.sub.z, where A, B and C are any combination of alkali metal, alkali-earth metal, transition metal, semimetal or metalloid and w, x, y and z are stoichiometric coefficients; (r) binary phosphates of type A.sub.x(PO.sub.4).sub.y, where A is an alkali metal, alkali-earth metal, transition metal, semimetal or metalloid and x and y are stoichiometric coefficients; (s) ternary phosphates of type A.sub.xB.sub.y(PO.sub.4).sub.z, where A and B are any combination of alkali metal, alkali-earth metal, transition metal, semimetal or metalloid and x, y and z are stoichiometric coefficients; (t) quaternary phosphates of type A.sub.wB.sub.xC.sub.y(PO.sub.4).sub.z, where A, B and C are any combination of alkali metal, alkali-earth metal, transition metal, semimetal or metalloid and w, x, y and z are stoichiometric coefficients; and (u) metals of type M where M is an alkali metal, alkali-earth metal, transition metal, semimetal or metalloid.

32. The method of claim 1, wherein a plurality of unique artificial SEI is grown sequentially via electrodeposition as a stack on the surface of the battery electrode by repeating (a)-(d).

33. (canceled)

34. The method of claim 1, wherein the predetermined amount of time is at least 5 seconds, 10 seconds, 30 seconds, 1 minute, 2, minutes, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25, minutes, 30 minutes, 45 minutes, or 1 hour.

35. The method of claim 34, wherein the predetermined amount of time is selected to allow for a solid-precipitating reaction to occur on the surface of the battery electrode.

36. The method of claim 1, wherein the battery electrode in (a) is a fully-formed battery electrode.

37. (canceled)

38. A solution-phase electrodeposition system for generating an artificial SEI onto the surface of a battery electrode, the system comprising: a conveyance apparatus for conveying the battery electrode to an electrodeposition chamber containing a liquid solution comprising at least a first reagent and an electrolyte: a counter electrode contained within the electrodeposition chamber that is exposed to the liquid solution, and an electrical source for producing voltage or current required for generating the artificial SEI, wherein the electrical source is in contact with the battery electrode and the counter electrode.

39. (canceled)

40. The system of claim 38, comprising a thermal chamber and a reference electrode contained within the electrodeposition chamber that is exposed to the liquid solution, and wherein the conveyance apparatus is a roll-to-roll apparatus.

41-43. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0054] FIG. 1 is an illustration of a battery electrode coated with an artificial SEI in accordance with the present disclosure.

[0055] FIG. 2 is a schematic drawing of an embodiment for coating an artificial SEI onto the surface of a battery electrode via electrodeposition in accordance with the disclosure.

[0056] FIG. 3 is a schematic drawing of an embodiment for coating an artificial SEI onto the surface of a battery electrode via electrodeposition using a reference electrode in accordance with the disclosure.

[0057] FIG. 4 is a schematic drawing of an embodiment for coating an artificial SEI onto the surface of a battery electrode via electrodeposition using multiple chambers in accordance with the disclosure.

DETAILED DESCRIPTION

[0058] The present disclosure provides liquid/solution-phase electrodeposition methods and systems for forming artificial solid-electrolyte interphase (“SEI”) coatings on electrodes. To date, techniques for forming conformal coatings of thin films (<10 micrometer (μm) thickness) on substrates such as lithium-ion battery electrodes, which possess a microstructure comprising a high degree of porosity, tortuosity and/or large number of high aspect ratio features (i.e., “non-planar” microstructure) are either ineffective (“line of sight” limitation of physical vapor deposition) or are costly and time-consuming (traditional Atomic Layer Deposition (ALD)). Embodiments of the present disclosure achieve a cost-effective means for forming uniform, conformal layers on non-planar microstructures.

[0059] The method refers generally to a liquid-phase electrodeposition process for the deposition of artificial SEI layers. These thin films may be used to coat the surfaces of components of electrochemical devices such as batteries. In particular, for batteries, such as lithium ion batteries, applications that may benefit with the coatings described herein may include high-voltage cathodes, fast charging, silicon-containing anodes, cheaper electrolytes, and nanostructured electrodes. Thus, in some embodiments, the artificial SEI thin films may be coated onto an electrode of a battery, such as a cathode or anode.

[0060] The methods and systems provided herein relate to generating an “artificial SEI” layer in batteries that are more resistant to dissolution than current SEIs, have sufficient adhesion to the material or component to be coated with adequate mechanical stability, are reasonably electrically resistive to prevent electrolyte breakdown while being conductive of ions (as in the case of batteries, for example lithium ions), and are substantially devoid of any particle-to-particle internal resistance.

[0061] An example of an embodiment of a coated battery electrode in accordance with the present disclosure is shown in FIG. 1. A coated battery electrode, 100, comprises bound electrode constituent active material particles, 102, that are coated with the artificial SEI, 103. The artificial SEI, 103, may be between 0.5 nm to 100 μm thick. The electrode constituent particles, 102, are situated on top of a substrate, 101. In this embodiment, the electrode constituent active material particles, 102, and the substrate, 101, yield a pre-formed electrode.

[0062] In some embodiments, an electrode comprises a porous coating of an active material on top of a substrate, such as a foil or a sheet. In some embodiments, the battery electrode comprises graphite, Si, Sn, Ge, Al, P, Zn, Ga, As, Cd, In, Sb, Pb, Bi, SiO, SnO.sub.2, a Si-graphite composite, a Sn-graphite composite or lithium metal. In some cases, the battery electrode comprises LiNi.sub.xMn.sub.yCo.sub.xO.sub.2, LiNi.sub.xCo.sub.yAl.sub.zO.sub.2, LiMn.sub.xNi.sub.yO.sub.z, LiMnO.sub.2, LiFePO.sub.4, LiMnPO.sub.4, LiNiPO.sub.4, LiCoPO.sub.4, LiV.sub.2O.sub.5, sulfur or LiCoO.sub.2 where x, y and z are stoichiometric coefficients.

[0063] In certain embodiments, the substrate may be a continuous substrate, typically in the form of a foil or sheet. A “continuous substrate” as used herein refers to a substrate that possesses an aspect ratio of at least 10:1 between its two largest dimensions, and is sufficiently flexible so as to be wound onto itself in the form of a roll. It may be made up of various materials, including but not limited to metal, such as copper, aluminum, or stainless steel, or an organic material, such as polyimide, polyethylene, polyether ether ketone (PEEK), or polyester, polyethylene napthalate (PEN).

[0064] A simple schematic for an embodiment of the method in accordance with the disclosure is shown in FIG. 2. While the embodiment of FIG. 2 is related to a method for coating an artificial SEI onto the surface of a battery electrode, this description is only representative of a component to be deposited using the methods and systems provided herein and is not to be construed as being limited in any way. Referring to FIG. 2, a battery electrode, for example, may be exposed to a fluid in an electrodeposition chamber or tank. The chamber or tank further comprises one or more counter electrodes. Multiple counter electrodes may be employed to improve uniformity of electric field between counter electrodes and battery electrode. Typically, the battery electrode is polarized oppositely relative to counter electrode. The battery and counter electrodes may be polarized positively or negatively relative to each other depending on whether species in tank is anionic or cationic. When both cationic and anionic species are present in the chamber or tank, relative polarity between the battery and counter electrodes may be swept from positive to negative and back again, as in a typical cyclic voltammograrn, to sequentially react cationic and anionic species in order to precipitate artificial SET on the battery electrode surface. In some embodiments, both cationic and anionic components of the resulting artificial SET may deposit and react to form the artificial SET at or near the same voltage or current versus a counter electrode; such a process is said to occur potentiostatically or galvanostatically, respectively. In some embodiments, the electrodeposition chamber or tank may further comprise a reference electrode, as shown in FIG. 3. Reference electrodes may be employed in order to individually define the voltage of either the battery electrode or the counter electrode against an electrochemically non-participating electrode.

[0065] The liquid solution comprises at least a first reagent. The first reagent may comprise any compound or element that is able to be electrodeposited on the surface of a lithium-ion battery electrode. In certain embodiments, the first reagent is a metalorganic compound. Examples of such metalorganics include, but are not limited to, aluminum tri-sec butoxide, titanium ethoxide, niobium ethoxide, trimethyl aluminum, and zirconium tert-butoxide. In another embodiment, the first reagent comprises an aqueous solution comprising an ionic compound. Examples include, but are not limited to, zinc acetate, cadmium chloride, zinc chloride, zirconium chloride, selenium oxide and zinc sulfate. In some embodiments, the first solution may vary in pH. In some embodiments, the liquid solution may be a solution including ionic compounds of both cationic and anionic precursors that react to form a solid film (the artificial SEI); in this case the film growth is limited by the kinetics of the film-forming reaction. In some embodiments, the liquid solution may be a solution including both metalorganic and oxidizing precursors that react to form a solid film; in this case the film growth is limited by the kinetics of the film-forming reaction.

[0066] In certain embodiments, the kinetics of the electrodeposition artificial SEI-forming reaction is controlled galvanostatically by limiting the electrical current passing between the battery electrode substrate, counter electrode and electrolyte. In certain embodiments, the kinetics of the electrodeposition artificial SEI-forming reaction is controlled potentiostatically by holding the voltage of the battery electrode substrate, relative to the counter electrode, constant at some pre-determined value.

[0067] In certain embodiments, the liquid solution may also comprise a solvent that is used to dissolve or complex the first reagent. Preferred solvents include organic solvents, such as an alcohol, for example, isopropyl alcohol or ethanol, alcohol derivatives such as 2-methoxyethanol, slightly less polar organic solvents such as pyridine or tetrahydrofuran (THF), nonpolar organic solvents such as hexane and toluene, water, or an ionic liquid comprising ions including, but not limited to, methylimidazolium and pyridinium.

[0068] The electrode is exposed to the liquid solution for a sufficient time (a “residence time”) so as to allow the first reagent(s) to permeate throughout an electrode's porous network, followed by electrodeposition onto an electrode surface in order to generate a continuous layer. Examples of process variables that may influence the electrodeposition process include solution and electrode temperature, residence time, reagent concentration, pH, voltage and current.

[0069] The battery electrode is exposed to a voltage or current in the liquid solution for a predetermined amount of time for the solid-precipitating reaction to occur. In some embodiments, the predetermined amount of time may be at least 5 seconds, 10 seconds, 30 seconds, 1 minute, 2, minutes, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25, minutes, 30 minutes, 45 minutes, 1 hour, or more.

[0070] In one embodiment, the liquid solution is contained within a reaction chamber. The reaction chamber must be a device large enough to accommodate receiving the electrode and to contain the amount of liquid solution to be used in electrodeposition reaction. In some embodiments, the system or method may comprise multiple electrodeposition reaction chambers. Such devices that may be used as the reaction chamber include, but are not limited to, tanks, baths, trays, beakers, or the like.

[0071] In other embodiments, the compound formed as part of the artificial SEI may comprise Transition Metal Dichalcogenides (TMDs). Typical examples of this class of materials follow the general chemical formula MX.sub.2, where M is a transition metal such as Mo, W, Ti, etc., and X is either S or Se.

[0072] Multiple sequential or repeated steps of the same process can be performed with the same or different solutions. Solutions may be separated (as in first solution, second solution, etc.) to avoid cross-contamination, for instance, or to prevent homogenous nucleation when a heterogeneous film-forming reaction is preferred. An embodiment comprises the use of multiple electrodeposition chambers or tanks used in sequence is shown in FIG. 4, where the battery electrode is passed from one chamber or tank to the next by a conveyance apparatus (shown in the figure as a roll-to-roll system).

[0073] It is to be understood that the various steps of the methods disclosed herein may be carried out by a system. The system may include a conveyance apparatus, reaction and/or rinsing chambers, filtration devices, a thermal chamber, a computer to control and/or automate the system, an electrical source for producing the voltage or current needed to carry out the electrodeposition, and monitoring devices, such as ion-selective electrodes or float sensors. The conveyance apparatus is preferably automated and, in some embodiments, comprises a series of rollers, such as tensioning rollers, positioned in such a manner as to guide or direct the electrode into and out of the chambers. In this way, the system can provide for a continuous liquid electrodeposition process for coating an artificial SEI thin film onto the surface of an electrode.

EXAMPLES

Example 1: Deposition of ZnO

[0074] A lithium-ion battery electrode is conveyed into an electrodeposition chamber, where it is submerged in an aqueous solution containing 0.1M Zn(NO.sub.3).sub.2. A Pt wire counter electrode is also submerged in the solution. The temperature of the solution is adjusted to be 70 degrees Celsius. A ZnO artificial SEI is electrodeposited onto the lithium-ion battery electrode from the aforementioned precursor, galvanostatically, by maintaining a constant current of −7 mA/cm.sup.2 between the battery electrode and counter electrode. The current is also pulsed on and off at a rate of once every 0.02 seconds.

Example 2: Deposition of Al metal

[0075] A lithium-ion battery electrode is conveyed into an electrodeposition chamber, wherein it is submerged in a solution of AlCl.sub.3 in DMSO. A Pt wire counter electrode is also submerged in the solution. The temperature of the solution is adjusted to be 130 degrees Celsius. An Al metal artificial SEI is electrodeposited onto the lithium-ion battery electrode from the aforementioned precursor, galvanostatically, by maintaining a constant current of −5 mA/cm.sup.2 between the battery electrode and counter electrode. After deposition of the Al metal film, the electrode may be thermally treated in an oxygen plasma in order to convert the metal to amorphous aluminum oxide.

Example 3: Deposition of CdSe

[0076] A lithium-ion battery electrode is conveyed into an electrodeposition chamber, wherein it is submerged in an aqueous solution containing SeO.sub.2, CdSO.sub.4 and sulfuric acid. A Pt wire counter electrode is also submerged in the solution. The pH of the resulting solution is adjusted to be approximately 3. The temperature of the solution is adjusted to be 60 degrees Celsius. A CdSe artificial SEI is electrodeposited onto the lithium-ion battery electrode from the aforementioned precursors, galvanostatically, by maintaining a constant current of −1.5 mA/cm.sup.2 between the battery electrode and counter electrode.

[0077] It should be understood from the foregoing that, while particular implementations have been illustrated and described, various modifications can be made thereto and are contemplated herein. It is also not intended that the present disclosure be limited by the specific examples provided within the specification. While certain embodiments have been described with reference to the aforementioned specification, the descriptions and illustrations of the preferable embodiments herein are not meant to be construed in a limiting sense. Furthermore, it shall be understood that all aspects of the present disclosure are not limited to the specific depictions, configurations or relative proportions set forth herein which depend upon a variety of conditions and variables. Various modifications in form and detail of the embodiments will be apparent to a person skilled in the art. It is therefore contemplated that the present disclosure shall also cover any such modifications, variations and equivalents.