Prosecution Insights
Last updated: April 19, 2026
Application No. 17/919,126

LITHIUM-SULFUR SECONDARY BATTERY COMPRISING CYCLIC CARBONATE-CONTAINING ELECTROLYTE

Final Rejection §103
Filed
Oct 14, 2022
Examiner
KYLE, MADISON LEIGH
Art Unit
1722
Tech Center
1700 — Chemical & Materials Engineering
Assignee
LG Energy Solution, Ltd.
OA Round
2 (Final)
50%
Grant Probability
Moderate
3-4
OA Rounds
3y 6m
To Grant
-7%
With Interview

Examiner Intelligence

Grants 50% of resolved cases
50%
Career Allow Rate
4 granted / 8 resolved
-15.0% vs TC avg
Minimal -57% lift
Without
With
+-57.1%
Interview Lift
resolved cases with interview
Typical timeline
3y 6m
Avg Prosecution
53 currently pending
Career history
61
Total Applications
across all art units

Statute-Specific Performance

§103
56.2%
+16.2% vs TC avg
§102
20.1%
-19.9% vs TC avg
§112
21.3%
-18.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 8 resolved cases

Office Action

§103
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 . Status of Claims Claims 1, 4, and 6-11 are currently pending; Claims 2-3 and 5 are canceled; Claims 1, 4-5, and 11 are currently amended. Status of Objections and Rejections Pending Since the Office Action of 07/15/2025 The objection of claim 8 is withdrawn in view of Applicant’s amendment; The 103 rejections of claims 1-11 are withdrawn and replaced with 103 rejections of Park in view of Guo and Park in view of Guo and Cooke. Response to Arguments Applicant's arguments filed 09/24/2025 have been fully considered but they are not persuasive. In regards to the criticality of the range of sub-1,000 ppm range, the Examiner respectfully disagrees. Only 1 example is given that shows the difference of a higher range from the claimed range for fluoroethylene carbonate (example 1 and comparative example 2) and vinylene carbonate (example 2 and comparative example 10), and only 1 example is given that shows the difference of a lower value than the claimed range for fluoroethylene carbonate (example 1 and comparative example 1) and vinylene carbonate (example 2 and comparative example 9). This is not sufficient evidence for criticality. Whether the unexpected results are the result of unexpectedly improved results or a property not taught by the prior art, the "objective evidence of nonobviousness must be commensurate in scope with the claims which the evidence is offered to support." In other words, the showing of unexpected results must be reviewed to see if the results occur over the entire claimed range. In re Clemens, 622 F.2d 1029, 1036, 206 USPQ 289, 296 (CCPA 1980). See also In re Peterson, 315 F.3d 1325, 1329-31, 65 USPQ2d 1379, 1382-85 (Fed. Cir. 2003) (data showing improved alloy strength with the addition of 2% rhenium did not evidence unexpected results for the entire claimed range of about 1-3% rhenium); In re Grasselli, 713 F.2d 731, 741, 218 USPQ 769, 777 (Fed. Cir. 1983) (Claims were directed to certain catalysts containing an alkali metal. Evidence presented to rebut an obviousness rejection compared catalysts containing sodium with the prior art. The court held this evidence insufficient to rebut the prima facie case because experiments limited to sodium were not commensurate in scope with the claims.). In regards to the Applicant’s argument concerning the lack of factual support for the weight percentage of the fluorinated linear ether based on a total weight of the non-aqueous solvent is optimizable (see Remarks, pgs. 7-8), the Examiner respectfully disagrees. A person of ordinary skill in the art would be able to find the densities of the solvent components of the liquid electrolyte such as to arrive at a reasonable weight percentage. Further, there is motivation to optimize the volumetric ratio of the solvent components of Park such as to achieve the target effects of suppressing gas generation (Park [0053]) without declining battery properties ([0038]) such as to reasonably arrive at the claimed weight range of the fluorinated linear ether based on a total weight of the non-aqueous solvent. In regards to Applicant’s argument concerning criticality of the claimed weight range of the fluorinated linear ether based on a total weight of the non-aqueous solvent, the Examiner respectfully disagrees. There is insufficient support in the instant specification for criticality based on paragraph [0038]. There is insufficient evidence showing how the claimed weight range improves the performance of the battery in comparison to when the weight range is outside the claimed range. The evidence relied upon should establish "that the differences in results are in fact unexpected and unobvious and of both statistical and practical significance." Ex parte Gelles, 22 USPQ2d 1318, 1319 (Bd. Pat. App. & Inter. 1992) (Mere conclusions in appellants’ brief that the claimed polymer had an unexpectedly increased impact strength "are not entitled to the weight of conclusions accompanying the evidence, either in the specification or in a declaration."); Ex parte C, 27 USPQ2d 1492 (Bd. Pat. App. & Inter. 1992) (Applicant alleged unexpected results with regard to the claimed soybean plant, however there was no basis for judging the practical significance of data with regard to maturity date, flowering date, flower color, or height of the plant.). See also In re Nolan, 553 F.2d 1261, 1267, 193 USPQ 641, 645 (CCPA 1977) and In re Eli Lilly, 902 F.2d 943, 14 USPQ2d 1741 (Fed. Cir. 1990). Applicant’s arguments with respect to newly amended claim 1 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument in regards to Park and Noh being incompatible electrolyte systems (Remarks pg. 6). Claim Rejections - 35 USC § 103 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. Claims 1, 4, 6 and 9-11 are rejected under 35 U.S.C. 103 as being unpatentable over Park et al. (US-20180301739-A1), hereinafter Park, in view of Guo et al. (CN-110416597-A), hereinafter Guo, as cited in the IDS. Regarding claim 1, Park teaches a lithium-sulfur secondary battery ([0010]-[0011]) comprising a positive electrode, a negative electrode, a separator ([0066]), and an electrolyte ([0010]-[0011]), the electrolyte further comprises a non-aqueous solvent and a lithium salt ([0012]), and the non-aqueous solvent contains a fluorinated linear ether ([0016]). Park does not explicitly teach that the non-aqueous solvent comprises 50 wt.% to 99 wt.% of the fluorinated linear ether based on a total weight of the non-aqueous solvent. However, the weight percent of the fluorinated linear ether based on a total weight of the non-aqueous solvent is optimizable. Park does teach that the volume ratio of the cyclic ether and the linear ether is from 5:95 to 95:5 ([0053]). Given such a range, it would have been obvious to someone of ordinary skill in the art, before the effective filing date of the claimed invention, to optimize the weight percent of the fluorinated linear ether based on a total weight of the non-aqueous solvent within the given volume ratio such that the non-aqueous solvent comprises 50 wt.% to 99 wt.% of the fluorinated linear ether based on a total weight of the non-aqueous solvent. Doing so allows for target effects to be obtained of suppressing gas generation ([0053]), such that swelling is improved ([0024]). [W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). Park fails to teach that the electrolyte contains a cyclic carbonate, and the cyclic carbonate is fluoroethylene carbonate, vinylene carbonate, or a combination thereof, wherein an amount of the cyclic carbonate in the electrolyte is more than 0 ppm and less than 1,000 ppm based on the total weight of the electrolyte. Guo is considered analogous to the claimed invention because they are in the same field of lithium sulfur batteries ([0002]). Guo teaches that the electrolyte contains a cyclic carbonate, and the cyclic carbonate is fluoroethylene carbonate, vinylene carbonate, or a combination thereof ([0028] vinylene carbonate or fluoroethylene carbonate), wherein an amount of the cyclic carbonate in the electrolyte is more than 0 ppm and less than 1,000 ppm based on the total weight of the electrolyte ([0028] 0 to 10 mass percent). In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). Therefore, it would have been obvious to someone of ordinary skill in the art, before the effective filing date of the claimed invention, to have modified Park to further include a cyclic carbonate additive in the claimed amount. Doing so would improve the performance of the lithium sulfur battery through SEI film formation (Guo [0028]). Regarding claim 4, modified Park teaches all of the limitations of claim 1. Park also teaches that the fluorinated linear ether is selected from the group consisting of 1,1,2,2-tetrafluoroethyl 2,2,3,3- tetrafluoropropyl ether, 1,1,2,2-tetrafluoroethyl 2,2,2- trifluoroethyl ether, bis(fluoromethyl) ether, bis(2,2,2-trifluoroethyl) ether, propyl 1,1,2,2- tetrafluoroethyl ether, isopropyl 1,1,2,2-tetrafluoroethyl ether, 1,1,2,2-tetrafluoroethyl isobutyl ether, 1,1,2,3,3,3- hexafluoropropyl ethyl ether, 1H,1H,2'H,3H-decafluorodipropyl ether, 1H,1H,2'H-perfluorodipropyl ether, and combinations thereof ([0016]). Regarding claim 6, modified Park teaches all of the limitations of claim 1. Park also teaches that the lithium salt is selected from the group consisting of LiN(FSO2)2, LiSCN, LiN(CN)2, LiN(CF3SO2)2, LiN(CF3CF2SO2)2, LiPF6, LiF, LiCl, LiBr, LiI, LiNO3, LiClO4, LiAlO4, LiAlCl4, LiSbF6, LiAsF6, LiBF2C2O4, LiBC4O8, Li(CF3)2PF4, Li(CF3)3PF3, Li(CF3)4PF2, Li(CF3)5PF, Li(CF3)6P, LiCF3SO3, LiC4F9SO3, LiCF3CF2SO3, LiCF3CF2(CF3)2CO, Li(CF3SO2)2CH, LiCF3(CF2)7SO3, LiCF3CO2, LiCH3CO2, and combinations thereof ([0020]). Regarding claim 9, modified Park teaches all of the limitations of claim 1. Park also teaches that the positive electrode comprises a positive electrode active material, and the positive electrode active material is a sulfur-carbon composite ([0070]). Regarding claim 10, modified Park teaches all of the limitations of claim 9. Park also teaches that the sulfur-carbon composite comprises 60 wt.% to 90 wt.% of sulfur based on a total weight of the sulfur-carbon composite ([0094] 65% by weight of sulfur). Regarding claim 11, modified Park teaches all of the limitations of claim 1. Park also teaches that the non-aqueous solvent further comprises a non- fluorinated linear ether, a cyclic ether, a polyether or a mixture thereof ([0012] the non-aqueous solvent includes a cyclic ether). Claims 7-8 are rejected under 35 U.S.C. 103 as being unpatentable over Park in view of Guo as applied to claim 1 above, and further in view of Cooke et al. (US-20220293925-A1), hereinafter Cooke. Regarding claim 7, modified Park teaches all of the limitations of claim 1. Park also teaches that the positive electrode comprises a positive electrode active material layer ([0073]). Park fails to teach that the positive electrode active material layer has a porosity of 30% or more and less than 70%. However, this range of porosity for lithium-sulfur cathodes is common in the art. Cooke is considered analogous to the claimed invention because they are in the same field of lithium sulfur batteries ([0001]). Cooke discloses that lithium-sulfur cells contain cathodes with a high porosity typically falling in the range of 60-80% to allow for standard electrolytes to penetrate the cathode and allow high sulfur utilization in the cathode ([0003]). Therefore, it would be obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have further defined the porous positive electrode of Park to have porosity in the typical range for lithium sulfur batteries as disclosed by Cooke in order to facilitate electrolyte penetration in the cathode, effective mass transport in the electrolyte, and high sulfur utilization throughout the cathode (Cooke [0003]). Regarding claim 8, modified Park teaches all of the limitations of claim 7. Park also teaches that a loading amount of the positive electrode active material of the positive electrode is 3.0 mAh/cm2 to 10.0 mAh/cm2 ([0094] loading amount of 5 mAh/cm2). Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure: US 20190123385 A1 teaches an embodiment with essentially no vinylene carbonate, meaning preferably less than 0.1 wt% of vinylene carbonate, in an electrolyte composition ([0079]) for a lithium sulfur battery ([0094]). EP 1063719 A1 teaches a nonaqueous electrolytic solution with vinylene carbonate greater than 1 ppm and less than 100 ppm ([0027]). 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 MADISON L KYLE whose telephone number is (571)272-0164. The examiner can normally be reached Monday - Friday 9 AM - 5 PM ET. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Niki Bakhtiari can be reached at (571) 272-3433. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /M.L.K./Examiner, Art Unit 1722 /NIKI BAKHTIARI/Supervisory Patent Examiner, Art Unit 1722
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Prosecution Timeline

Oct 14, 2022
Application Filed
Jul 11, 2025
Non-Final Rejection — §103
Sep 24, 2025
Response Filed
Jan 06, 2026
Final Rejection — §103
Apr 01, 2026
Request for Continued Examination
Apr 05, 2026
Response after Non-Final Action

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Study what changed to get past this examiner. Based on 4 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
50%
Grant Probability
-7%
With Interview (-57.1%)
3y 6m
Median Time to Grant
Moderate
PTA Risk
Based on 8 resolved cases by this examiner. Grant probability derived from career allow rate.

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