DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Amendment
Applicant’s amendments filed October 13, 2025 have been entered. Claims 1, 7-8, 11, and 14 have been amended; support for the amendments can be found in the cancelled claims and at least in paragraph [0044] of the Instant Specification. Claims 20-30 are new; support for the new claims can be found at least in paragraphs [0056] and [0058] of the Instant Specification. Claims 4-6, 9-10 and 15-19 are cancelled. Claims 1-3, 7-8, 11-14, and 20-30 remain pending and have been examined on their merits in this office action.
Applicant has cancelled claim 5; therefore, the previous 112(b) rejection has been withdrawn.
Response to Arguments
Applicant’s arguments filed October 13, 2025 have been fully considered but are considered moot in view of the new grounds of rejection below in view of Applicant’s amendments to the independent claim 1.
Claim Objections
Claim 8 is objected to because of the following informalities: “dimethylbenze” should read “dimethyl benzene” (see Instant Specification paragraph [0044]). Appropriate correction is required.
Claims 24 and 25 are objected to because of the following informalities: “azetropic” should read “azeotropic.” Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 7-8, 21-22, and 25 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 7 recites the limitation "the distillate.” There is insufficient antecedent basis for this limitation in the claim.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-2, 7-8, and 21-28 are rejected under 35 U.S.C. 103 as being unpatentable over Liu et al. (CN 110436424 A), hereinafter referred to as Liu, in view of Malone et al. (“Reactive Distillation” (2000)), hereinafter referred to as Malone.
Regarding claim 1, Liu teaches a method for preparing lithium bis(fluorosulfonyl)imide (see e.g., Abstract). Liu ‘424 teaches a lithium source, such as LiOH, Li2CO3, or a mixture thereof, bis(fluorosulfonyl)imide, and solvent are mixed (see e.g., paragraph [0036]), and water is generated from the reaction (“reacting hydrogen bis(fluorosulfonyl)imide (HFSI) with a lithium salt selected from lithium hydroxide (LiOH), lithium carbonate (Li2CO-3), and combinations thereof, in a first solvent to produce a composition comprising the first solvent, lithium bis(fluorosulfonyl)imide (LiFSI) and water”) (see e.g., paragraph [0082]). Liu ‘424 teaches the solvent is a hydrophobic polar aprotic solvent or a solvent that can form an azeotrope with water (see e.g., paragraph [0037]) because when the solvent used is one that forms an azeotrope with water, the water generated during the reaction of the lithium source and bis(fluorosulfonyl)imide is miscible with the solvent, diluting and dispersing it (see e.g., paragraph [0084]).
Liu teaches in order to further reduce the moisture content in the lithium bis(fluorosulfonyl)imide, a step that involves dissolving, filtering, and drying the obtained crude lithium bis(fluorosulfonyl)imide in a hydrophobic polar aprotic solvent to obtain lithium bis(fluorosulfonyl)imide (“distilling the composition to separate at least some of the first solvent and water as an overhead distillate from the lithium bis(fluorosulfonyl)imide (LiFSI), wherein a bottom comprises lithium bis(fluorosulfonyl)imide (LiFSI)”) (see e.g., paragraph [0085]). Liu does not explicitly teach the step involves distilling via azeotropic distillation.
However, Malone teaches a known technique of reactive distillations, such as azeotropic distillation, to improve separation of the azeotrope (see e.g., Introduction) and carry out the reaction simultaneously with distillation that cannot be achieved by carrying out these steps sequentially (see e.g., Step 1: Feasibility and Alternatives).
Therefore, because Liu teaches the selection of a solvent that can form an azeotrope with water, it would have been obvious before the effective filing date of the claimed invention that one of ordinary skill would modify the step of Liu to include the known technique of azeotropic distillation, as taught by Malone, to separate the solvent, lithium bis(fluorosulfonyl)imide (LiFSI), and water, in order to improve separation (see e.g., Malone Introduction) of the purification step to remove moisture and obtain a high quality lithium bis(fluorosulfonyl)imide (see e.g., Liu paragraph [0006]).
Regarding claim 2, Liu, as modified by Malone, teaches the instantly claimed invention of claim 1, as previously described.
Liu teaches the lithium source includes LiOH (“wherein the lithium salt comprises lithium hydroxide (LiOH)”) (see e.g., paragraph [0041]).
Regarding claim 7, Liu, as modified by Malone, teaches the instantly claimed invention of claim 1, as previously described.
Liu teaches a purification step after the lithium bis(fluorosulfonyl)imide has been dried in which the dried lithium bis(fluorosulfonyl)imide is dissolved, filtered, and dried in a hydrophobic polar aprotic solvent such as xylene (see e.g., paragraph [0083]) to effectively reduce the moisture content of the final obtained lithium bis(fluorosulfonyl)imide (“further comprising adding a second solvent to the distillate, and separating, at least some of the second solvent and water from the lithium bis(fluorosulfonyl)imide (LiFSI) to produce a second distillate comprising lithium bis(fluorosulfonyl)imide (LiFSI)”) (see e.g., paragraph [0085]).
Liu does not explicitly teach this purification step occurs via an azeotropic distillation. However, Malone teaches a known technique of reactive distillations, such as azeotropic distillation, to improve separation of the azeotrope (see e.g., Introduction) and carry out the reaction simultaneously with distillation that cannot be achieved by carrying out these steps sequentially (see e.g., Step 1: Feasibility and Alternatives).
Therefore, because Liu teaches the selection of a solvent that can form an azeotrope with water, it would have been obvious before the effective filing date of the claimed invention that one of ordinary skill would modify the purification step of Liu to include the known technique of azeotropic distillation, as taught by Malone, to separate the hydrophobic polar aprotic solvent, lithium bis(fluorosulfonyl)imide (LiFSI), and water, in order to improve separation (see e.g., Malone Introduction) of the purification step to remove moisture and obtain a high quality lithium bis(fluorosulfonyl)imide (see e.g., Liu paragraph [0006]).
Regarding claim 8, Liu, as modified by Malone, teaches the instantly claimed invention of claim 7, as previously described.
As previously described in claim 7, Liu teaches the hydrophobic polar aprotic solvent is selected from a group consisting of xylene (“wherein the second solvent comprises at least one solvent selected from xylenes, toluene, ethylbenzene, dimethyl benzene, and mesitylene”) (see e.g., paragraph [0083]).
Regarding claim 21, Liu, as modified by Malone, teaches the instantly claimed invention of claim 8, as previously described.
As previously described in claim 8, Liu teaches the hydrophobic polar aprotic solvent is selected from a group consisting of xylene (“where the second solvent comprises xylenes”) (see e.g., paragraph [0083])
Regarding claim 22, Liu, as modified by Malone, teaches the instantly claimed invention of claim 7, as previously described.
As previously described in claim 7, the hydrophobic polar aprotic solvent such as xylene is utilized in order to separate the water from xylene (see e.g., paragraph [0083]) and the lithium bis(fluorosulfonyl)imide (LiFSI) and would, therefore, have a separation between a xylene-rich phase and the rest (“where an overhead containing xylene is separated into a xylene-rich phase, and the xylene rich phase is recycled to a distillation column”).
Regarding claim 23, Liu, as modified by Malone, teaches the instantly claimed invention of claim 1, as previously described.
Liu teaches the lithium source includes Li2CO3 (“where the lithium salt comprises lithium carbonate (Li2CO3)”) (see e.g., paragraph [0041]).
Regarding claim 24, Liu, as modified by Malone, teaches the instantly claimed invention of claim 1, as previously described.
Liu teaches the step is performed at reduced pressure of 650 Pa (6.5 mbar) (“wherein the azeotropic distillation is conducted at a pressure from 5 mbar to 60 mbar”) (see e.g., paragraph [0119]).
Regarding claim 25, Liu, as modified by Malone, teaches the instantly claimed invention of claim 7, as previously described.
Liu teaches the purification step is performed at reduced pressure of 650 Pa (6.5 mbar (“wherein the second azeotropic distillation is conducted at a pressure from 5 mbar to 60 mbar”) (see e.g., paragraph [0119]).
Regarding claim 26, Liu, as modified by Malone, teaches the instantly claimed invention of claim 1, as previously described.
Liu teaches the moisture content was measured to be 5 ppm (“wherein a water content of the lithium bis(fluorosulfonyl)imide (LiFSI) product is 100 ppm or less”) (see e.g., paragraph [0129]).
Regarding claim 27, Liu, as modified by Malone, teaches the instantly claimed invention of claim 1, as previously described.
Liu teaches the moisture content was measured to be 5 ppm (“wherein a water content of the lithium bis(fluorosulfonyl)imide (LiFSI) product is 50 ppm or less”) (see e.g., paragraph [0129]).
Regarding claim 28, Liu, as modified by Malone, teaches the instantly claimed invention of claim 1, as previously described.
Liu teaches the moisture content was measured to be 5 ppm (“wherein a water content of the lithium bis(fluorosulfonyl)imide (LiFSI) product is 10 ppm or less”) (see e.g., paragraph [0129]).
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Liu et al. (CN 110436424 A) in view of Malone et al. (“Reactive Distillation” (2000)), and further in view of Iwasaki et al. (WO 2017169874 A1), hereinafter referred to as Iwasaki.,
Regarding claim 3, Liu, as modified by Malone, teaches the instantly claimed invention of claim 1, as previously described.
Liu, as modified by Malone, does not explicitly teach a hydrophobic polar aprotic solvent or a solvent that can form an azeotrope with water comprises diethyl carbonate.
However, Iwasaki teaches a manufacturing method for a bis(halogenated sulfonyl)imide acid metal salt (see e.g., Abstract). Iwasaki teaches the step of mixing bis (halogenated sulfonyl) imide and alkali metal salt in an organic solvent such as diethyl carbonate (“wherein the first solvent comprises diethyl carbonate”) (see e.g., paragraph [0045]) in order to increase the yield of high quality lithium bis (halogenated sulfonyl) imide (see e.g., paragraph [0051]).
Therefore, it would have been obvious before the effective filing date of the claimed invention that one of ordinary skill would modify the solvent that can form an azeotrope with water of Liu, as modified by Malone, to be diethyl carbonate, as taught by Iwasaki, on order to increase the yield of high quality lithium bis (halogenated sulfonyl) imide (see e.g., paragraph [0051]).
Claims 11, 14, 20, and 29-30 are rejected under 35 U.S.C. 103 as being unpatentable over Liu et al. (CN 110436424 A) in view of Malone et al. (“Reactive Distillation” (2000)), and further in view of Liu et al. (CN 109734061 A), hereinafter referred to as Liu ‘061.
Regarding claim 11, Liu, as modified by Malone, teaches the instantly claimed invention of claim 1, as previously described.
Liu, as modified by Malone, does not explicitly teach further comprising, after the distilling step, adding a drying solvent to dry the lithium bis(fluorosulfonyl)imide (LiFSI), wherein the drying solvent comprises dichloromethane (DCM).
However, Liu ‘061 teaches a method for preparing lithium bis(fluorosulfonyl)imide (LiFSI) (“a process to produce lithium bis(fluorosulfonyl)imide (LiFSI)”) (see e.g., paragraph [0014]). Liu ‘061 teaches the method comprises mixing and reacting bis(fluorosulfonyl)imide with an alkaline lithium source, such as LiOH, Li2CO3, or mixtures thereof, in a non-aqueous solvent that can form an azeotrope with water to produce lithium bis(flourosulfonyl)imide, the non-aqueous solvent, and water (see e.g., paragraphs [0016] and [0019]). Liu ‘061 teaches the solid lithium bis(fluorosulfonly)imide can be further purified by dissolving it in an aprotic solvent such as dichloromethane (“further comprising, after the distilling step, adding a drying solvent to dry the lithium bis(fluorosulfonyl)imide (LiFSI), wherein the drying solvent comprises dichloromethane (DCM)”) (see e.g., paragraph [0083]).
Therefore, it would have been obvious before the effective filing date of the claimed invention that one of ordinary skill would modify the process of Liu, as modified by Malone, to add an aprotic solvent such as dichloromethane to the solid lithium bis(fluorosulfonly)imide product, as taught by Liu ‘061, in order to further purify the lithium bis(fluorosulfonly)imide (see e.g., paragraph [0083]).
Regarding claim 14, Liu, as modified by Malone and Liu ‘061, teaches the instantly claimed invention of claim 11, as previously described.
Liu teaches the moisture content was measured to be 5 ppm (“wherein a water content of the lithium bis(fluorosulfonyl)imide (LiFSI) product is 180 ppm or less”) (see e.g., paragraph [0129]).
Regarding claim 20, Liu, as modified by Malone, teaches the instantly claimed invention of claim 1, as previously described.
Liu, as modified by Malone, does not explicitly teach further comprising drying the lithium bis(fluorosulfonyl)imide (LiFSI) with a halogenated hydrocarbon solvent, to produce a lithium bis(fluorosulfonyl)imide (LiFSI) product.
However, Liu ‘061 teaches the solid lithium bis(fluorosulfonly)imide can be further purified by dissolving it in an aprotic solvent such as dichloromethane (“further comprising, after the distilling step, adding a drying solvent to dry the lithium bis(fluorosulfonyl)imide (LiFSI), wherein the drying solvent comprises dichloromethane (DCM)”) (see e.g., paragraph [0083]).
Therefore, it would have been obvious before the effective filing date of the claimed invention that one of ordinary skill would modify the process of Liu, as modified by Malone, to add an aprotic solvent such as dichloromethane to the solid lithium bis(fluorosulfonly)imide product, as taught by Liu ‘061, in order to further purify the lithium bis(fluorosulfonly)imide (see e.g., paragraph [0083]).
Regarding claim 29, Liu, as modified by Malone, teaches the instantly claimed invention of claim 1, as previously described.
Liu, as modified by Malone, does not explicitly teach wherein a chloride ion content of the lithium bis(fluorosulfonyl)imide (LiFSI) product is 5 ppm or less.
However, Liu ‘061 teaches the impurity of Cl of the different embodiments of lithium bis(fluorosulfonyl)imide is 2 ppm, 5 ppm, and 1 ppm (“wherein a chloride ion content of the lithium bis(fluorosulfonyl)imide (LiFSI) product is 5 ppm or less”) (see e.g., paragraphs [0111], [0015], [0117]). Liu teaches the impurity content of Cl in the lithium bis(fluorosulfonyl)imide meets the chloride ion content requirements of lithium salts for lithium batteries (see e.g., paragraph [0006]).
Therefore, it would have been obvious before the effective filing date of the claimed invention that one of ordinary skill would modify the chloride content of the lithium bis(fluorosulfonyl)imide of Liu, as modified by Malone, to be 2 ppm, 5 ppm, and 1 ppm, as taught by Liu ‘061, in order to meet the chloride ion content requirements of lithium salts for lithium batteries (see e.g., paragraph [0006]).
Regarding claim 30, Liu, as modified by Malone, teaches the instantly claimed invention of claim 1, as previously described.
Liu, as modified by Malone, does not explicitly teach wherein a chloride ion content of the lithium bis(fluorosulfonyl)imide (LiFSI) product is 1 ppm or less.
Liu ‘061 teaches the impurity of Cl of lithium bis(fluorosulfonyl)imide is 1 ppm (“wherein a chloride ion content of the lithium bis(fluorosulfonyl)imide (LiFSI) product is 1 ppm or less”) (see e.g., paragraph [0117]). Liu teaches the impurity content of Cl in the lithium bis(fluorosulfonyl)imide meets the chloride ion content requirements of lithium salts for lithium batteries (see e.g., paragraph [0006]).
Therefore, it would have been obvious before the effective filing date of the claimed invention that one of ordinary skill would modify the chloride content of the lithium bis(fluorosulfonyl)imide of Liu, as modified by Malone, to be 1 ppm, as taught by Liu ‘061, in order to meet the chloride ion content requirements of lithium salts for lithium batteries (see e.g., paragraph [0006]).
Claims 12-13 are rejected under 35 U.S.C. 103 as being unpatentable over Liu et al. (CN 110436424 A) in view of Malone et al. (“Reactive Distillation” (2000)) and Liu et al. (CN 109734061 A), and further in view of Zhao et al. (Published U.S. Patent Application US 2020/0148633 A1), hereinafter referred to as Zhao.
Regarding claim 12, Liu, as modified by Liu and Liu ‘061, teaches the instantly claimed invention of claim 11, as previously described.
Liu, as modified by Liu and Liu ‘061, does not explicitly teach wherein the weight/weight (w/w) ratio of lithium bis(fluorosulfonyl)imide (LiFSI) to dichloromethane (DCM) is 1:1 to 1:4.
However, Zhao teaches a method for preparing lithium bis(fluorosulfonyl)imide (LiFSI) (“a process to produce lithium bis(fluorosulfonyl)imide (LiFSI)”) (see e.g., Abstract). Zhao teaches adding a polar or nonpolar solvent to a resulting concentrated supernatant in order to reduce the difficulty of product separation and purification, and improve the reaction yield and product purity (see e.g., paragraph [0024]). Zhao teaches an addition amount of the polar or nonpolar solvent is 1-5 times that of the solid lithium bis(fluorosulfonyl)imide by weight (“wherein the weight/weight (w/w) ratio of lithium bis(fluorosulfonyl)imide (LiFSI) to dichloromethane (DCM) is 1:1 to 1:4”) (see e.g., paragraph [0022]).
Therefore, it would have been obvious before the effective filing date of the claimed invention that one of ordinary skill would modify the ratio of LiFSI to DCM of Liu, as modified by Malone and Liu ‘061, to be 1 ppm, as taught by Zhao, in order to reduce the difficulty of product separation and purification, and improve the reaction yield and product purity (see e.g., paragraph [0024]).
It has been held in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art,” and because weight ratio of the lithium bis(fluorosulfonyl)imide to the solvent is 1:1 to 1:5 overlaps with the recited range, a “prima facie” case of obviousness exists (see MPEP 2144.05(l)).
Regarding claim 13, Liu, as modified by Malone, Liu ‘061, and Zhao, teaches the instantly claimed invention of claim 12, as previously described.
As previously described in claim 12, Zhao teaches an addition amount of the polar or nonpolar solvent is 1-5 times that of the solid lithium bis(fluorosulfonyl)imide by weight (“wherein the weight/weight (w/w) ratio of lithium bis(fluorosulfonyl)imide (LiFSI) to dichloromethane (DCM) is 1:2”) (see e.g., paragraph [0022]).
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Katherine N Higgins whose telephone number is (703)756-1196. The examiner can normally be reached Mondays - Thursdays 7:30-4:30 EST, Fridays 7:30 - 11:30 EST.
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/KATHERINE N HIGGINS/Examiner, Art Unit 1728
/MATTHEW T MARTIN/Supervisory Patent Examiner, Art Unit 1728