WO2025076294A1

WO2025076294A1 - Controlled quenching of lithium from non-aqueous bath

Info

Publication number: WO2025076294A1
Application number: PCT/US2024/049887
Authority: WO
Inventors: Balaji Ganapathy; Nilesh Chimanrao Bagul; Bahubali S. UPADHYE; Visweswaren Sivaramakrishnan
Original assignee: Applied Materials Inc
Current assignee: Applied Materials Inc
Priority date: 2023-10-06
Filing date: 2024-10-04
Publication date: 2025-04-10
Anticipated expiration: 2026-04-06

Abstract

A method of lithium metal removal is disclosed. The method includes mixing a quenching agent with a non-aqueous bath; submerging a lithium coated component in the non-aqueous bath; and forming a lithium salt. In another embodiment, a method of lithium metal removal is disclosed. The method includes submerging a lithium coated component in a non-aqueous bath; mixing a quenching agent with the non- aqueous bath; and forming a lithium salt. In yet another embodiment, a method of lithium metal removal is disclosed. The method includes mixing a first quenching agent with a non-aqueous bath; reacting a first lithium coated component with the first quenching agent in the non-aqueous bath; forming a first lithium salt; mixing a second quenching agent with the non-aqueous bath; reacting a second lithium coated component with the second quenching agent in the non-aqueous bath; and forming a second lithium salt.

Description

CONTROLLED QUENCHING OF LITHIUM FROM NON-AQUEOUS BATH

BACKGROUND

Field

[0001] Embodiments of the present disclosure generally relate to methods for removing lithium deposits from a lithium deposition system. More particularly, the present disclosure relates to removing lithium from a lithium deposition system using a non-aqueous bath.

Description of the Related Art

[0002] Processing of flexible substrates, such as plastic films or foils and battery components, is in high demand in the packaging industry, semiconductor industries and other industries. Processing may include coating of a flexible substrate with a material, such as a metal. The economical production of these coatings is frequently limited by the thickness uniformity necessary for the product, the reactivity of the coating material, the cost of the coating materials, and the deposition rate of the coating materials. The most demanding applications generally entail that the deposition occur in a vacuum chamber for precise control of the coating thickness and the optimum optical or other material properties. The high capital cost of vacuum coating equipment necessitates high availability and high throughput of coated area for large-scale commercial applications. The coated area per unit time is typically proportional to the coated substrate width and the vacuum deposition rate of the coating material. High availability offsets high capital cost and facilitates economically viable commercial manufacturing.

[0003] A process that can utilize a large vacuum chamber has tremendous economic advantages. Vacuum coating chambers, substrate treating and handling equipment, and pumping capacity increase in cost less than linearly with chamber size; therefore, the most economical process for a fixed deposition rate and coating design will utilize the largest width and length substrate available. A larger substrate can generally be fabricated into discrete parts after the coating process is complete. In the case of products manufactured from a continuous web, the web is slit or sheet cut to either a final product dimension or a narrower web suitable for the subsequent manufacturing operations. [0004] One flexible substrate coating technique used is resistive or electron beam thermal evaporation. Thermal evaporation readily takes place when a source material is heated in an evaporation source assembly within a vacuum chamber. Above a minimum temperature, there is a sufficient vapor flux from the evaporation source assembly for material condensation on a cooler substrate. The ratio of material condensation on a cooler substrate versus the evaporation source assembly itself can be difficult to control and can lead to parasitic deposition on various chamber components. In the case of manufacturing metallic lithium coated foils and films, parasitic lithium deposits internal and adjacent to the evaporation source assembly can adversely affect the yield and quality of subsequently deposited lithium films. Coating large substrates necessitates using large chamber components wider than the substrate. Some components are impractical to frequently remove for ex-situ cleaning and are thus manually cleaned in-situ, which can be hazardous due to confined space combustible metal handling. Further, some aqueous solutions typically used to wet clean chamber components can produce undesirable corrosive neutralization byproducts, such as lithium hydroxide, which can damage chamber components. Further, some aqueous solutions can contaminate battery grade (high purity) lithium contained in the source charge resulting in source assembly thermal drift due to the formation of higher melting point lithium oxide. In addition, lithium oxide particles formed and liberated during hazardous manual preventative maintenance can nucleate coating defects on the lithium coated web which can adversely impact energy storage device safety and cycle life.

[0005] Thus, there is a need for methods for removing unwanted parasitic lithium deposits from chamber components.

SUMMARY

[0006] In one embodiment, a method of lithium metal removal is disclosed. The method includes mixing a quenching agent with a non-aqueous bath to form a nonaqueous quenching bath. A lithium coated component is submerged in the nonaqueous quenching bath to form a lithium salt and remove a lithium metal from the lithium coated component.

[0007] In another embodiment, a method of lithium metal removal is disclosed. The method includes submerging a lithium coated component in a non-aqueous bath. A quenching agent is mixed with the non-aqueous bath to form a non-aqueous quenching bath to form a lithium salt and remove a lithium metal from the lithium coated component.

[0008] In yet another embodiment, a method of lithium metal removal is disclosed. The method includes mixing a first quenching agent with a non-aqueous bath to form a first non-aqueous quenching bath. A first lithium coated component reacts with the first quenching agent in the non-aqueous quenching bath to form a first lithium salt and remove a lithium metal from the first lithium coated component. A second quenching agent is mixed with the first non-aqueous bath to form a second nonaqueous quenching bath. A second lithium coated component reacts with the second quenching agent in the second non-aqueous quenching bath to form a second lithium salt and remove the lithium metal from the second lithium coated component.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of its scope, and may admit to other equally effective embodiments.

[0010] Figure 1 illustrates a flow diagram of a first method of lithium metal removal, according to embodiments.

[0011] Figure 2A-2D illustrates a schematic flow diagram of the first method of lithium metal removal, according to embodiments.

[0012] Figure 3 illustrates a flow diagram of the second method of lithium metal removal, according to embodiments.

[0013] Figure 4A-4D illustrates a schematic flow diagram of the second method of lithium metal removal, according to embodiments.

[0014] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

DETAILED DESCRIPTION

[0015] Embodiments of the present invention generally relate to a system and method for removing lithium deposits from a lithium deposition system. More particularly, the present disclosure relates to removing lithium from a lithium deposition system using a non-aqueous bath.

[0016] Parasitic metallic lithium deposition on chamber components can adversely affect uniform lithium deposition yield and quality in a roll-to-roll deposition system. For example, unwanted parasitic lithium deposition on chamber components can react with moisture outgassing from the flexible web substrate and can induce chamber component emissivity drift due to metallic lithium oxide formation. Radiation heat transfer from thermal evaporators to a drum-cooled web increases due to unwanted parasitic lithium deposition on chamber components such as the deposition source, the radiation shield, and the edge mask. The unwanted parasitic lithium depositions react with moisture and form high emissivity lithium oxide coatings. It is difficult to measure and to compensate for a change in the ratio of radiation versus condensation energy received by the substrate over long coating campaigns between turnarounds. Reducing radiation energy is generally preferred to avoid exceeding the substrate thermal budget, for example, to avoid melting the web, while maximizing deposition rate. However, for some applications, at lower lithium deposition rates and slightly elevated substrate temperatures, it useful to produce metallic lithium coatings characterized by fine lithium crystals, and thus it is necessary to prevent radiation energy drift. On rare occasions, web defects or recipe errors cause the web to tear and lithium to condense directly on the cooling drum. Some cooling drums have fine features for providing a high and uniform gap pressure for high heat transfer between the web and substrate. It is useful to remove metallic lithium from these fine features on the drum surface without risk of fouling or corrosion.

[0017] Maintaining the source assembly temperature over time may require increasing the heater power over time due to evaporator source charge lithium oxide contamination. Further, parasitic deposition of lithium reduces roll-to-roll uniformity due to edge mask-and-web baffle fouling with metallic lithium, which further causes pump conductance decrease and lithium vapor plume instability, resulting in within roll transverse thickness nonuniformity. Manual removal of unwanted parasitic lithium deposits is not only hazardous but also increases chamber turnaround duration, which in turn increases the cost of ownership of the tool. For example, manual cleaning of evaporator parts can lead to lithium metal fires and necessitates complex fire protection systems that may be avoided if manual cleaning operations were automated within the isolated vacuum system. Further, conventional aqueous cleaning methods produce hazardous waste, which is costly to dispose of and in turn increases operating costs.

[0018] In one or more implementations, which can be combined with other implementations, the systems and methods herein enable high throughput and high efficiency cleaning to reduce metallic lithium via a non-aqueous bath. Economical lithium reclaim from the leaching solution is also included. In addition, one or more embodiments described provide for the precipitation of commercially valuable lithium salts.

[0019] Figure 1 is a flow diagram of the method 100 of lithium metal removal. Figures 2A-2E illustrates a schematic flow diagram of a non-aqueous bath 201 during the method 100. At operation 102, as shown in Figure 2A and Figure 2B, a quenching agent is mixed with a non-aqueous bath 201 to form a non-aqueous quenching bath 202. The non-aqueous bath 201 may be a paraffin bath. The quenching agent may be water, ethylene glycol, a hydroxystearic acid (e.g., 12-hydroxystearic acid), a fatty acid, a Bronstead acid, a stearic acid, a palmitic acid, or other materials having active hydrogen. The non-aqueous bath 201 is non-reactive with the lithium metal. The non-aqueous bath 201 reduces the likelihood of hazardous reactions during the lithium metal removal method 100 due to the non-reactivity of paraffin with lithium metal.

[0020] At operation 104, as shown in Figure 2C and 2D, a lithium coated component 203 is submerged in the non-aqueous quenching bath 202 to remove a lithium metal from the lithium coated component 203 and form a lithium salt 204. The lithium coated component 203 includes a base component 206 and the lithium metal. The lithium metal is coating the base component 206. The lithium salt 204 is precipitated from a reaction between the lithium coating and the quenching agent. The amount of quenching agent that is mixed with the non-aqueous bath 201 may be adjusted to control the reaction between the quenching agent and a lithium metal. The ratio of quenching agent to lithium metal to be quenched is about 1 :1 to about 1 :10. The reaction enables the removal of a lithium metal from the lithium coated component 203 through controlled use of the quenching agent. The quenching agent enables a controlled reaction with the highly reactive lithium metal, thereby controlling the hydrogen release and heat evolution of the lithium metal removal method 100. The lithium salt 204 includes lithium hydroxide, lithium alkoxides, lithium chloride, lithium phosphates, lithium sulfates, lithium stearates, lithium palmitates, and other similar salts. The reaction between the lithium coating and the quenching agent removes the lithium coating from the base component 206. The base component 206 may include a cooling drum or other components of a lithium coating deposition chamber.

[0021] At operation 106, the lithium salt 204 is collected. The lithium salt 204 forms a sludge at the bottom of the non-aqueous quenching bath 202. The lithium salt 204 may be collected using a sludge hopper, a chain scrapper, or other suitable mechanism. The quenching agent may increase the life span of the non-aqueous bath 201 , e.g., the method 100 may be repeated to remove the lithium coating from additional lithium coated components 203 using the same non-aqueous bath 201 . By forming a sludge of lithium salt 204 through the reaction between the lithium metal and the quenching agent in the non-aqueous quenching bath 202, the non-aqueous quenching bath does not become over-saturated. Thus, the non-aqueous quenching bath can be reused

[0022] The method 100 may be repeated to perform lithium metal removal from one or more additional lithium coated components 203. The quenching agent may be changed during the removal of lithium metal from a single lithium coated component 203, or between lithium coated components 203, in order to produce the desired lithium salt 204. The amount of lithium salt 204 produced may be controlled by adjusting the amount of quenching agent mixed with the non-aqueous bath 201. In addition, the formation of the lithium salt 204 may increase the life span of the nonaqueous bath 201 , e.g., the method 100 may be repeated to remove the lithium coating from additional lithium coated components 203 using the same non-aqueous bath 201 . [0023] Figure 3 illustrates a flow diagram of the method 300 of lithium metal removal. Figures 4A-4E illustrates a schematic flow diagram of a non-aqueous bath 401 during the method 300. At operation 302, as shown in Figure 4A and Figure 4B, a lithium coated component 403 is submerged in a non-aqueous bath 401. The nonaqueous bath 401 includes a paraffin bath. The lithium coated component 403 includes a base component 406 and the lithium metal. The lithium metal is coating the base component 406. The non-aqueous bath 401 is non-reactive with the lithium metal.

[0024] At operation 304, as shown in Figure 4C and Figure 4D, a quenching agent is mixed with the non-aqueous bath 401 to form a non-aqueous quenching bath 402 to remove a lithium metal from the lithium coated component 403 and form a lithium salt 404. The lithium salt 404 is precipitated from a reaction between the lithium coating and the quenching agent. The amount of quenching agent that is mixed with the non-aqueous bath 401 may be adjusted to control the reaction between the quenching agent and a lithium metal. The ratio of quenching agent to lithium metal to be quenched is about 1 : 1 to about 1 :10. The reaction enables the removal of a lithium metal from the lithium coated component 403 through controlled use of the quenching agent. The quenching agent enables a controlled reaction with the highly reactive lithium metal, thereby controlling the hydrogen release and heat evolution of the lithium metal removal method 300. The lithium salt 404 includes lithium hydroxide, lithium alkoxides, lithium chloride, lithium phosphates, lithium sulfates, lithium stearates, lithium palmitates, and other similar salts. The reaction between the lithium coating and the quenching agent removes the lithium coating from the base component 406. The base component 406 may include a cooling drum or other components of a lithium coating deposition chamber.

[0025] The quenching agent may be water, ethylene glycol, a hydroxystearic acid (e.g., 12-hydroxystearic acid), a fatty acid, a Bronstead acid, a stearic acid, a palmitic acid, or other materials having active hydrogen. The amount of quenching agent that is mixed with the paraffin bath may be adjusted to control the reaction between the quenching agent and the lithium metal. The non-aqueous bath 401 reduces the likelihood of hazardous reactions during the lithium metal removal method 300 due to the non-reactivity of paraffin with lithium metal. [0026] At operation 306, the lithium salt 404 is collected. The lithium salt 204 forms a sludge at the bottom of the non-aqueous quenching bath 202. The lithium salt 204 may be collected using a sludge hopper, a chain scrapper, or other suitable mechanism.

[0027] The method 300 may be repeated to perform lithium metal removal from one or more additional lithium coated components 403. The quenching agent may be changed during the removal of lithium metal from a single lithium coated component 403, or between lithium coated components 403, in order to produce the desired lithium salt 404. The amount of lithium salt 404 produced may be controlled by adjusting the amount of quenching agent mixed with the non-aqueous bath 401. In addition, the formation of the lithium salt 404 may increase the life span of the nonaqueous bath 401 , e.g., the method 300 may be repeated to remove the lithium coating from additional lithium coated components 403 using the same non-aqueous bath 401 .

[0028] In summary, a method of removing lithium metal from lithium coated components is disclosed. The method enables the removal of lithium metal through controlled use of a non-aqueous bath. The non-aqueous bath includes a paraffin bath and a quenching agent. The quenching agent is added to a paraffin bath to form a quenching agent paraffin bath either before or after a lithium coated component is placed into the non-aqueous bath. The quenching agent is a material that enables a controlled reaction of the highly reactive lithium metal. The quenching agent reacts with a lithium coated component in a paraffin bath to form a lithium salt. The use of a paraffin bath reduces the likelihood of hazardous reactions during the lithium removal process due to the non-reactivity of paraffin with lithium metal. The lithium salt can be collected.

[0029] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

What is claimed is:

1 . A method of lithium metal removal, comprising: mixing a quenching agent with a non-aqueous bath to form a non-aqueous quenching bath; submerging a lithium coated component in the non-aqueous quenching bath to remove a lithium metal from the lithium coated component and form a lithium salt, wherein the lithium coated component includes a base component and the lithium metal coating the base component; and collecting the lithium salt.

2. The method of claim 1 , wherein the non-aqueous bath is a paraffin bath.

3. The method of claim 1 , wherein the lithium salt may be collected using a sludge hopper or a chain scrapper.

4. The method of claim 1 , wherein a ratio of quenching agent to lithium metal is about 1 :1 to about 1 :10.

5. The method of claim 1 , wherein the lithium salt includes lithium hydroxide, lithium alkoxides, lithium chloride, lithium phosphates, lithium sulfates, lithium stearates, or lithium palmitates.

6. The method of claim 1 , wherein the quenching agent comprises water, ethylene glycol, a hydroxystearic acid, a fatty acid, a Bronstead acid, a stearic acid, a palmitic acid, or other materials having an active hydrogen.

7. The method of claim 1 , wherein the mixing and submerging of the lithium coated component is repeated for one or more lithium coated components.

8. A method of lithium metal removal, comprising: submerging a lithium coated component in a non-aqueous bath; mixing a quenching agent with the non-aqueous bath to form a non-aqueous quenching bath to remove a lithium metal from the lithium coated component and form a lithium salt; and collecting the lithium salt.

9. The method of claim 8, wherein the non-aqueous bath is a paraffin bath.

10. The method of claim 8, wherein a ratio of quenching agent to lithium metal is about 1 :1 to about 1 :10.

11 . The method of claim 8, wherein the lithium salt may be collected using a sludge hopper or a chain scrapper.

12. The method of claim 8, wherein the lithium salt includes lithium hydroxide, lithium alkoxides, lithium chloride, lithium phosphates, lithium sulfates, lithium stearates, or lithium palmitates.

13. The method of claim 8, wherein the quenching agent comprises water, ethylene glycol, a hydroxystearic acid, a fatty acid, a Bronstead acid, a stearic acid, a palmitic acid, or other materials having an active hydrogen.

14. The method of claim 8, wherein the submerging and mixing of the lithium coated component is repeated for one or more lithium coated components.

15. A method of lithium metal removal, comprising: mixing a first quenching agent with a non-aqueous bath to form a first nonaqueous quenching bath; reacting a first lithium coated component with the first quenching agent in the first non-aqueous quenching bath to form a first lithium salt and remove a lithium metal from the first lithium coated component; mixing a second quenching agent with the first non-aqueous quenching bath to form a second non-aqueous quenching bath, wherein the second quenching agent is different from the first quenching agent; and reacting a second lithium coated component with the second quenching agent in the second non-aqueous quenching bath to form a second lithium salt and remove the lithium metal from the second lithium coated component.

16. The method of claim 15, further comprising collecting the first lithium salt prior to mixing the second quenching agent.

17. The method of claim 16, wherein collecting the first lithium salt is performed using a sludge hopper or a chain scrapper.

18. The method of claim 16, wherein a ratio of quenching agent to lithium metal is about 1 :1 to about 1 :10.

19. The method of claim 15, wherein the first quenching agent and the second quenching agent comprise water, ethylene glycol, a hydroxystearic acid, a fatty acid, a Bronstead acid, a stearic acid, a palmitic acid, or other materials having an active hydrogen.

20. The method of claim 15 wherein the first lithium salt or the second lithium salt includes lithium hydroxide, lithium alkoxides, lithium chloride, lithium phosphates, lithium sulfates, lithium stearates, or lithium palmitates.