JP2003515888A - Method and apparatus for producing a lithium-based cathode - Google Patents

Abstract

SUMMARY A method is provided for making a layer of a lithiated material, wherein a mixture of Li (acac) and Co (acac) ₃ is dissolved in an aqueous solvent to form a solution. The solution is deposited by atomizing, passing the atomized solution through a heated gas stream to vaporize the solution, and directing the vaporized solution onto a substrate.

Description

Detailed Description of the Invention

[0001]

[Industrial application field (technical field)]

The present invention relates generally to thin film batteries, and more particularly to the manufacture of lithium cathodes for thin film rechargeable lithium ion batteries.

[0002]

BACKGROUND OF THE INVENTION (Background of the Invention)

Today's conventional canister-type (can-type) batteries contain toxic substances such as cadmium, mercury, lead and acid electrolytes. These chemicals are currently faced with governmental regulations or prohibitions as manufacturing materials, thus limiting their use as battery components. Another problem associated with these battery materials is that the amount of energy stored and delivered is proportional to the size and weight of the active ingredients used therein. Large batteries, such as those found in automobiles, produce large amounts of current, but have a very low energy density (watt hour / liter) and specific energy (watt hour / gram). Therefore, they require long charging times, which makes them impractical for many applications.

To meet the demand for higher energy densities and specific energies, the battery industry has moved toward producing lithium-based batteries. The battery industry has mainly focused on liquid and polymer electrolyte systems. However, these systems have inherent safety issues due to the volatility of the electrolyte solvent. Further, this type of battery has a relatively high ratio of inactive substance components such as a current collector (current collector), a separator and a substrate as compared with active energy storage substances used for an anode (anode) and a cathode (cathode). have. Moreover, their relatively high internal impedance results in a low rate capability (watts / kilogram),
This makes them impractical for many applications.

Thin film lithium batteries are constructed as having a stacked form of film starting with an inert ceramic substrate on which the cathode current collector and cathode are mounted. A solid state electrolyte is deposited on the cathode, an anode is deposited on the electrolyte, and an anode current collector is mounted on the anode. A protective coating is typically applied to the entire cell. This type of lithium battery is described in
5,569,520 and 5,597,660, the disclosures of which are specifically incorporated herein. However, the lithiated cathode material of these batteries has a (003) alignment of the lithium cell, as shown in Figure 1, which results in high internal cell resistance and large capacity loss.

Thin film batteries have also been made by forming active cathode materials through chemical vapor deposition techniques. In the past, chemical vapor deposition cathodes have been manufactured in extremely low pressure environments in the 1-100 Torr range. This extremely low pressure environment requirement significantly increases manufacturing costs and greatly reduces the likelihood of producing a commercially viable product as a result of its control difficulties. Furthermore, this type of chemical vapor deposition is typically carried out by heating the precursor solution to cause vaporization of the solution into the vapor phase, so that it is carried away to the deposition site through a stream of non-reactive gas such as argon. Can be Heating the precursor over a long period of time can result in decomposition of the solution and therefore go wrong. Furthermore, the high temperature and low pressure of this system necessitate thorough heating of the transport line carrying the solution in order to prevent the evaporated solution from condensing between the heating and vapor deposition locations, and thus further production. Increase the cost and complexity involved in

[0006] Recently, it has been discovered that annealing lithiated cathode materials on a substrate under the proper conditions results in cells with significantly enhanced performance because the annealing causes crystallization of the lithiated material. . This crystallized material is Li
And alternating planes containing Co ions have a hexagonal layered structure separated by layers that are tightly packed with oxygen. A LiCoO ₂ film deposited on an alumina substrate by magnetron sputtering and crystallized by annealing at 700 ° C. has a layer of oxygen, cobalt and lithium as illustrated by the (101) plane shown in FIG. Has been found to exhibit a highly preferred orientation or texture (texture) oriented substantially perpendicular to the substrate. This orientation is preferred because the lithium planes are aligned parallel to the direction of current flow, thus providing high lithium ion diffusion through the cathode. It is believed that this preferred orientation is formed because the extreme heating during annealing produces a large volumetric strain energy that is oriented substantially parallel to the underlying rigid substrate surface. As crystals are formed, they naturally grow in the direction of least energy strain, thus the annealing process and the resulting volumetric strain energy promote crystal growth in a direction substantially perpendicular to the underlying substrate surface. That direction is also the preferred orientation for diffusion of ions through the crystal.

[Characterization of Thin-Film Rechargeable Lithium Batteries]
With Lithium Cobalt Oxide Cathodes) (the Journal of The Electrochemica
l Society, Vol. 143, No. 10) ", B. Wang, JB Bates, F
.X. As reported by Hart, BC Sales, Sales, RA Tool (Zuhr), JD Robertson, in the past, the annealing temperature of 600 ° C or less has caused the lithium material to have a microstructure. Did not change significantly, so the lithium orientation remained amorphous. This amorphous state limits diffusion of lithium ions through the oxygen and cobalt layers, thus resulting in high internal cell resistance and large capacity loss.

Therefore, in order to anneal the lithiated cathode material to the most efficient orientation, the cathode had to be bonded to a rigid substrate and had to be heated to near 700 ° C. for long periods of time.

Another problem associated with chemical vapor deposition of lithium-based cathodes is associated with solvents used in combination with precursor materials such as lithium-, cobalt-, magnesium-, nickel- or iron-based materials. It was a thing. Typically such solvents are extremely volatile and create fire and explosion hazards at elevated temperatures.

Therefore, a cathode for use in a high performance rechargeable thin film battery without the need for an ultra low pressure system, without the annealing of the cathode and without the use of volatile solvents is provided. It turns out that there is still a need for a method of manufacture. Therefore, the main purpose of the present invention is to provide the same.

[0011]

[Means for Solving the Problems (Summary of Invention)]

In a preferred form of the invention, a method of producing a layer of LiCoO ₂ comprises preparing a lithium-based solution (a solution containing a substance containing a lithium component) and spraying the lithium-based solution. To form a mist that heats the gas stream and entrains the atomized lithium-based solution mist into the heated gas stream so that the mist of the lithium-based solution is heated to the gaseous state. And depositing the vapor on the substrate.

[0012]

[Example (Detailed Description)]

Referring now to the drawings, there is shown a cell 10 of a rechargeable thin film lithium battery made according to a method using the principles of the present invention in a preferred embodiment (FIG. 4).
. The cell 10 of the battery has an aluminum cathode current collector (aluminum cathode current collector) 11 sandwiched between two cathodes 12. The cathode 12 is made of a lithium intercalation compound (lithium insertion compound) or a lithium metal oxide such as LiCoO ₂ , LiMgO ₂ , LiNiO ₂ , LiFeO ₂ . Each cathode 12 has a solid state electrolyte 13 formed thereon. The electrolyte 13 is preferably made of lithium phosphorous oxynitride (Li _x PO _y N _z ). Further, each electrolyte 13 has an anode 14 deposited thereon. The anode 14 is preferably silicon-tin oxynitride (Si) when used in a lithium-ion battery.
TON) or other suitable material such as lithium metal, zinc nitride or tin nitride. Finally, an anode current collector 16 (15?), Preferably made of copper or nickel, contacts both anodes 14 and substantially houses the cathode collector 11, cathode 12, electrolyte 13 and anode 14 therein. ing.

The method of the present invention will use the vapor deposition apparatus shown in FIG. The device comprises a holding tank 20 connected to an ultrasonic generator 21. The holding tank 20 has an air inlet 22 connected to an air pump 23 and an outlet pipe 24, the outlet pipe 24 extending to an injection pipe 25 having a nozzle 27 at one end. The injection tube 25 is connected to a heating element 28.
The nozzle 27 faces a heater block 29 located adjacent to the nozzle 27.

The battery cell 10 is preferably manufactured by the following method. Li (TMHD), commonly called lithium (2,2,6,6-tetramethyl-3,5-heptadionate), i.e. Li (C ₁₁ H ₁₉ O ₂ ).
And Co (acac) ₃ , commonly referred to as cobalt (III) acetylacetonate,
That is, a mixture with Co (C ₅ H ₇ O ₂ ) ₃ was dissolved in an organic solvent, for example, a mixture of diglyme (diethylene glycol dimethyl ether), toluene and HTMHD to form a solution, which was kept in the holding tank 20. An ultrasonic generator 21 or any other conventional atomizer produces a mist stream of solution. The mist has a droplet size distribution between 5 and 20 microns, with a preferred droplet size of approximately 5 μM. The mist droplets are carried through the outlet tube 24 to the ejection tube 25 due to the force of the pressurized air introduced from the air pump 23 through the air inlet 22 into the holding tank. The air flow at the air inlet is pressurized between 1-2 psi.

The injection tube 25 is heated to approximately 200 ° C. so that the mist droplets passing through the injection tube 25 are vaporized. This vapor is then directed onto a substrate located approximately 1.5-2 inches (3.81-5.08 cm) from the end of the nozzle. This substrate is heated to approximately 400 by the underlying heating block 29.
Heat to ℃. As the vapor approaches and contacts the heated substrate, Li (TMH
D) and Co (acac) ₃ react with O ₂ in the surrounding air, forming a layer of LiCoO ₂ on the surface of the substrate and the generation of volatile organic gases, the latter being evacuated. It has been discovered that the resulting LiCoO ₂ layer is produced as crystals having a preferred orientation along the (101) plane as shown in FIG. The substrate can then be flipped over to apply the layer on the opposite side.

The following examples are given for illustrative purposes only and are not meant to be a limitation of the invention.

0.25 g of Li (TMHD) and 0.5 g of Co (acac) ₃ were added to diglyme, toluene and HTMHD.
A solution was made by mixing into an organic solvent having a volume of 53 mL consisting of a mixture of. This mixture contained 40 mL diglyme, 10 mL toluene and 3 mL HTMHD. This solution offers important advantages as it can be handled in air without any adverse effects. Atomized solution at a rate of 2 liters per minute
Through a 1/4 inch (0.64 cm) inner diameter outlet tube 24 and through an approximately 2 inch (5.08 cm) long injection tube heated to 200 ° C. to achieve complete vaporization of the mist. The resulting vapor was directed from nozzle 27 onto a SiO ₂ substrate located approximately 1.5 inches (3.81 cm).

The resulting LiCoO ₂ layer has three concentric distinct regions: a central first region R1 having a dark green glowing appearance, a first region having a dark green appearance It appears to have a second region R2 surrounding R1 and a third region R3 surrounding a second region R2 having a light green appearance. This non-uniformity is believed to be due to the injection regimen used in the experiment.

Referring now to FIGS. 6-8, SEM (scanning electron microscope) photographs of the first, second and third regions, respectively, are shown. 6 and 8 show that the first and third regions of the layer are approximately
It is shown to be extremely smooth with a very uniform texture eye size of 100 nm. This smoothness and textured mesh size provide an unprecedented cathode structure never before achieved by conventional vapor deposition methods. This layer does not show any signs of cracking or flaking.

As shown in FIG. 12, the X-ray diffraction patterns of all three regions show a high degree of good texture in the (101) plane. It should be appreciated that the peaks associated with the LiCoO ₂ phase are sharp, indicating that this phase has good crystallinity. This figure also approximates to be associated with an amorphous SiO ₂ substrate.
It also shows a broad peak at 22 °.

The LiCoO ₂ sample layer was then annealed at 650 ° C. for 30 minutes. Comparison of the pre-annealed sample and the post-annealed sample shows little difference. 9-11 show the first, second and third regions of the sample after annealing, respectively. It should be noted that the crystal structure in the (101) plane remains very similar to that shown by comparison with FIG. 13 in FIG. Therefore, the annealing process does not provide a significant benefit to the cathode layer.

Of particular importance is the appearance of cracks in the sample after the annealing step, as shown on the far right in FIG. This type of cracking of the cathode material is a problem that the Applicant is trying to avoid as it causes cathode degradation which can render the cell ineffective.

Therefore, it should be understood that the present invention results in the formation of LiCoO ₂ layers with the growth of proper (101) plane crystals. Moreover, the present invention achieves this result without the need for annealing the LiCoO ₂ layer to achieve proper (101) plane crystal growth. Finally, this is achieved using chemical vapor deposition at ambient conditions.

Once the cathode layer is complete, the remaining battery parts, such as electrolyte 13, anode 14,
Anode collector 16 can be applied. The electrolyte and anode can be applied using any conventional means, such as sputtering, chemical vapor deposition, spray pyrolysis, laser abrasion, ion beam evaporation (vapor deposition) and the like.

The length of the injection tube 25, the flow rate through the injection tube, and the heating of the injection tube are all variables that must be adjusted to achieve proper evaporation of mist droplets through the injection tube, That is, the heat input must match the boiling point of the solvent. The injection tube can be heated by any conventional means, such as microwave irradiation, heating lamps, resistance coils and the like. Also, any conventional device can be used to atomize or atomize the solution. The method of the present invention also includes a method of spraying the solution in the form of a mist. The fog morphology described above is then passed through a heating zone to evaporate the fog before it reaches the substrate by the heating element 28, as illustrated in FIG.

Also, different lithium and cobalt compounds or chelate compounds can be used in the process of the invention, preferably vaporized at 300 ° C. or below. However, the compounds mentioned offer the important advantage that they can be handled in air.

Finally, it should be understood that it is preferred that only the first region R1 is used as the cathode of the cell. It is believed that through suitable placement of multiple nozzles, the dimensions of the first region R1 can be optimized while the second and third regions R2 and R3 are minimized or eliminated altogether.

Referring now to FIGS. 14, 15 and 16, a second method of making a lithium layer in another preferred form of the invention is described. This method of the present invention uses the chemical vapor deposition apparatus 40 shown in FIG. The apparatus 40 includes a copper heating chamber 42 having a heating element 43 therein, the heating element 43 preferably being made of nichrome or other suitable resistive heating wire such as platinum. Also, the copper heating chamber 42 has a temperature probe 44 for monitoring the temperature therein. Heating element 43
Is connected to a variable transformer 46 which controls the power to the resistance heating element 43 and thus the heat in the heating chamber. The heating chamber 42 is in fluid communication with a pressurized tank 47 via a tube 48. Pressurized tank 47 contains a supply of compressed inert gas such as nitrogen or argon. The heating chamber 42 is also in fluid communication via a tube 51 with a supply of precursor solution contained within a non-reactive storage container 50 made of polyethylene or the like. The storage container 50 contains an ultrasonic generator 52, which atomizes the solution as described above. The storage container 50 is also in fluid communication via line 55 with a supply of compressed inert gas in a pressure tank 47. Tubes 48 and 53 are metering valves 54 that control the flow of gas through each tube.
have. A nozzle 55 is associated with the heating chamber 42 for directing a stream of heated gas stream entrained with the precursor onto the adjacent substrate 56. The nozzle is preferably made of ceramic and has an opening of approximately 1 mm. As best shown in FIG. 15, the nozzle 55 is connected to the tube 51 and has an internal passage shape that creates a Venturi effect that helps the precursor to be withdrawn from the tube, providing uniform heating gas flow and precursor flow. Results in mixing. The substrate can also include a temperature probe to monitor the temperature of the gas during deposition.

The battery cells are preferably made with the device 40 just described in the following manner. A metering valve 54 connected to tube 48 is opened to allow an inert gas flow to flow from pressure tank 47 to heating chamber 42, where heating element 43 causes heating element 43 to pass through the heating chamber. Raise the temperature to approximately 600 ° C. Similarly, the metering valve 54 of the tube 53 is opened so that the inert gas pressurized thereby flows through the tube 53 into the storage container 50.

A mixture of lithium acetylacetonate and cobalt (III) acetylacetonate, which is dissolved in an aqueous solvent to form a solution and is held in the storage container 50, is an ultrasonic generator 5
Although atomized by the actuation of 2, the ultrasonic generator 52 can again be any other type of conventional atomizer that atomizes a portion of the solution into a mist. Ultrasonic generator
The precursor fog droplets created by 52 are delivered into a preheated inert gas stream at a rate in the range of 5 to 50 mL / hour. The mist droplets of precursor are carried through tube 51 to heating chamber nozzle 55 by the force of the pressurized inert gas entering storage container 50.

Upon entering the heating chamber 42 downstream of the heating element 43, the precursor droplets are flash vaporized where the vapor is entrained in the heated gas stream. The precursor droplets are further reacted in contact with the heated gas stream. This helps chemically activate the precursor to allow subsequent deposition on the substrate. This stream is then directed to the substrate by nozzle 55, which is located approximately 0.28 inches (0.71 cm) from nozzle 55, where the vaporized precursors arrive at substrate 56 and decompose into mixed oxides. To be done. The substrate 56 is heated to approximately 350 ° C. In this case the mixed oxide is lithium cobalt oxide and it is believed that the deposition rate of lithium cobalt oxide is approximately 0.5 micron / hour.

Referring now to FIG. 15, there is shown a photocopy of a lithium cobalt oxide layer produced on a alumina ceramic substrate by the method previously described. This layer contains 150 mL deionized water, 0.09 g lithium (acac) and 0.3 g cobalt (acac) ₃
Was made using a solution consisting of The inert gas was released from pressure tank 47 at 30 psi and substrate 56 was heated to approximately 350 ° C. As illustrated in FIG. 15, the resulting layer contains triangular / pyramidal crystals, forming a nearly favorable crystal growth, reducing the need for layer annealing.

Referring now to FIG. 17, an apparatus similar to that shown in FIG. 14 is shown except that the pressure tank 47 is not in fluid communication with the storage container 50. Here, the precursor is drawn through tube 51 through the force of Venturi only.

It should be understood that a similar device could be devised as without the Venturi nozzle, or a spray nozzle could be used to deliver droplets into the heating chamber downstream of the heating element 43. .

The term aqueous solvent, as used herein, is intended to include predominantly water-based solvents, and thus may include other additional substances such as organic solvents. It should also be understood that the method just described can be accomplished without external heating of the substrate.

What we see here is a good discharge produced without an ultra-low pressure environment and without a non-reactive gas environment, but containing a good crystallographic arrangement without the need for subsequent annealing. A high rate capability battery cathode is provided here. It should of course be understood that many modifications may be made to the particular preferred embodiments described herein without departing from the spirit and scope of the invention as set forth in the following claims. is there.

[Brief description of drawings]

FIG. 1 is a schematic representation of a lithium intercalation compound oriented along the (003) plane.

FIG. 2 is a schematic diagram of a lithium intercalation compound oriented along the preferred (101) plane.

FIG. 3 is a plan view of a thin film lithium battery illustrating the principles of the present invention in a preferred embodiment.

[Figure 4]   FIG. 4 is a cross-sectional view of the thin film lithium battery of FIG. 3 taken along the plane 4-4.

FIG. 5 is a schematic diagram of an apparatus used to deposit on the cathode of the thin film lithium battery of FIG.

FIG. 6 is a photocopy showing a first region of a cathode layer deposited according to the method of the preferred embodiment.

FIG. 7 is a photocopy showing a second region of the cathode layer deposited according to the method of the preferred embodiment.

FIG. 8 is a photocopy showing a third region of the cathode layer deposited according to the method of the preferred embodiment.

FIG. 9 is a photocopy showing a first region of a cathode layer after annealing according to the method of the preferred embodiment.

FIG. 10 is a photocopy showing a second region of a cathode layer after annealing according to a preferred embodiment method.

FIG. 11 is a photocopy showing a third region after annealing of a cathode layer deposited according to the method of the preferred embodiment.

FIG. 12 is a graph of an X-ray diffraction pattern of a cathode layer deposited according to the method of the preferred embodiment.

FIG. 13 is a graph of an X-ray diffraction pattern after annealing of a cathode layer deposited according to the method of the preferred embodiment.

14 is a schematic diagram of an apparatus used to attach to the cathode of the thin film lithium battery of FIG.

FIG. 15   FIG. 15 is a sectional view of the nozzle of the apparatus shown in FIG.

FIG. 16 is a photocopy showing a cathode layer deposited according to another embodiment.

FIG. 17 is a schematic diagram of an apparatus used to deposit another preferred embodiment cathode.

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE, TR), OA (BF , BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, G M, KE, LS, MW, MZ, SD, SL, SZ, TZ , UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, B Z, CA, CH, CN, CR, CU, CZ, DE, DK , DM, DZ, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, J P, KE, KG, KP, KR, KZ, LC, LK, LR , LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NO, NZ, PL, PT, R O, RU, SD, SE, SG, SI, SK, SL, TJ , TM, TR, TT, TZ, UA, UG, US, UZ, VN, YU, ZA, ZW (72) Inventor Erbil, Ahmet             United States 30318 Georgia             Atlanta Frances Street D             NW 1180 F term (reference) 5H029 AJ14 AK03 AL11 AM12 BJ04                       BJ12 CJ02 CJ22 CJ28 CJ30                       DJ17 HJ05 HJ14                 5H050 AA19 BA17 CA08 CB12 FA02                       FA18 GA02 GA22 GA27 GA29                       HA05 HA14

Claims (49)

[Claims] 1. (a) preparing a lithium-based solution, (b) spraying the lithium-based solution to form a mist, (c) heating a gas stream, (d) Entraining an atomized lithium-based solution in the preheated gas stream to heat a mist of the lithium-based solution to a vapor state, and (e) depositing the vapor on a substrate. A method of manufacturing a lithium intercalation material cathode layer of a thin film battery, the method including: 2. The method of claim 1 wherein the gas stream is heated to a temperature to cause chemical activation of the lithium-based solution. 3.   The method of claim 1, further comprising (f) heating the substrate. 4.   The method of claim 1, wherein the vapor is deposited through a nozzle. 5. The method of claim 1, wherein the lithium-based solution is a lithium compound and a cobalt compound dissolved in an aqueous solvent. 6.   The method of claim 5, wherein the lithium compound is Li (acac). 7. The method of claim 5, wherein the cobalt compound is Co (acac) ₃ . 8. The method of claim 1, wherein the fog has a droplet size distribution between 5 and 20 microns. 9. The method of claim 1 wherein the gas stream comprises or comprises an inert gas. 10.   The method of claim 9, wherein the stream of inert gas comprises hydrogen. 11.   10. The method of claim 9, wherein the stream of inert gas comprises argon. 12. A solution having (a) a mixture of Li (acac) and Co (acac) ₃ dissolved in an aqueous solvent is prepared, and (b) the solution is treated to form a mist. Of the lithium metal oxide comprising: (c) entraining the mist in a stream of preheated gas sufficient to cause vaporization of the mist, and (d) depositing the vapor on a substrate. How to make layers. 13.   13. The method of claim 12, further comprising (e) heating the substrate. 14. The method of claim 13, wherein the fog has a droplet size distribution between 5 and 20 microns. 15. The method according to claim 12, wherein the gas stream consists of or comprises an inert gas. 16.   16. The method of claim 15, wherein the inert gas is hydrogen. 17.   16. The method of claim 15, wherein the inert gas is argon. 18. A solution is prepared comprising (a) a mixture of a lithium-based compound and a cobalt-based compound dissolved in a solvent, and (b) treating the solution to produce a fog. Forming a lithium metal oxide comprising: (c) entraining the mist in a stream of heated gas sufficient to cause vaporization of the mist, and (d) depositing the vapor on a substrate. How to build layers. 19.   19. The method of claim 18, wherein the solvent is an aqueous solvent. 20. The method according to claim 18, wherein the gas stream consists of or comprises an inert gas. 21.   21. The method of claim 20, wherein the inert gas is hydrogen. 22.   21. The method of claim 20, wherein the inert gas is argon. 23.   21. The method of claim 20, wherein the inert gas is argon. 24. Means for generating a gas flow, heating means for heating the gas flow generated by the means for generating a gas flow, holding means for holding a precursor solution supplied, said precursor solution Precursor delivery means for delivering the precursor solution from the holding means to the gas stream downstream of the heating means, comprising atomization means for atomizing
And a means for directing the gas stream containing the heated precursor solution onto a substrate. 25. The apparatus of claim 24, wherein the precursor delivery means comprises a supply of pressurized gas in fluid communication with the holding means. 26. The means for generating the gas stream comprises a supply of pressurized inert gas.
The device according to. 27. (a) preparing a lithium based solution; (b) spraying the lithium based solution to form a mist; (c) atomizing the lithium based solution. A method of making a lithium intercalation material cathode layer of a thin film battery comprising heating to a vapor state and (d) depositing the vapor on a substrate. 28.   28. The method of claim 27, further comprising (e) heating the substrate. 29.   28. The method of claim 27, wherein the vapor is deposited through a nozzle. 30.   30. The method of claim 29, wherein the mist is vaporized before passing through the nozzle. 31.   30. The method of claim 29, wherein the mist is vaporized after passing through the nozzle. 32. The method of claim 27, wherein the lithium-based solution is a lithium compound and a cobalt compound dissolved in an organic solvent. 33.   33. The method of claim 32, wherein the lithium compound is Li (TMHD). 34. The method of claim 32, wherein the cobalt compound is Co (acac) ₃ . 35.   33. The method of claim 32, wherein the organic solvent comprises diglyme. 36.   33. The method of claim 32, wherein the organic solvent comprises toluene. 37.   33. The method of claim 32, wherein the organic solvent comprises HTMHD. 38. The method of claim 32, wherein the organic solvent is a mixture of diglyme, toluene and HTMHD. 39. The method of claim 27, wherein the fog has a droplet size distribution between 5 and 20 microns. 40. Preparing (a) a solution having a mixture of Li (TMHD) and Co (acac) ₃ dissolved in an organic solvent, and (b) treating the solution to form a mist. , (C) heating the mist of the solution to a vapor state, and (d) depositing the vapor on a substrate. 41.   41. The method of claim 40, further comprising (e) heating the substrate. 42.   41. The method of claim 40, wherein the vapor is deposited through a nozzle. 43.   41. The method of claim 40, wherein the mist is vaporized before passing through the nozzle. 44.   41. The method of claim 40, wherein the mist is vaporized after passing through the nozzle. 45.   41. The method of claim 40, wherein the organic solvent comprises diglyme. 46.   41. The method of claim 40, wherein the organic solvent comprises toluene. 47.   41. The method of claim 40, wherein the organic solvent comprises HTMHD. 48. The method of claim 40, wherein the organic solvent is a mixture of diglyme, toluene and HTMHD. 49. The method of claim 40, wherein the fog has a droplet size distribution between 5 and 20 microns.