Prosecution Insights
Last updated: April 18, 2026
Application No. 17/918,104

LITHIUM-SULFUR SECONDARY BATTERY COMPRISING ELECTROLYTE CONTAINING S-O-BASED CYCLIC COMPOUND

Non-Final OA §103
Filed
Oct 10, 2022
Examiner
ARMSTRONG, KAREN JOYCE
Art Unit
1726
Tech Center
1700 — Chemical & Materials Engineering
Assignee
LG Energy Solution, Ltd.
OA Round
3 (Non-Final)
79%
Grant Probability
Favorable
3-4
OA Rounds
3y 5m
To Grant
91%
With Interview

Examiner Intelligence

Grants 79% — above average
79%
Career Allow Rate
15 granted / 19 resolved
+13.9% vs TC avg
Moderate +12% lift
Without
With
+11.9%
Interview Lift
resolved cases with interview
Typical timeline
3y 5m
Avg Prosecution
58 currently pending
Career history
77
Total Applications
across all art units

Statute-Specific Performance

§101
1.2%
-38.8% vs TC avg
§103
59.1%
+19.1% vs TC avg
§102
25.7%
-14.3% vs TC avg
§112
12.2%
-27.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 19 resolved cases

Office Action

§103
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 The amendment filed on 08/19/2025 does not place the application in condition for allowance. The rejection of claims 1, 4, and 6-11 under U.S.C 103 is maintained The cancellation of claims 2, 3, and 5 is acknowledged. Response to Arguments Regarding the rejection of claims 1, 2, 3, and 5 (now all present in newly amended claim 1) the applicant argues Youn alone does not teach the combined limitations and there are unexpected and superior results in Examples 1-4 and Comparative Examples 1-32. The examiner respectfully disagrees with the assertion there are unexpected and superior results and points out applicant has not specified which results in particular are material or how they are unexpected or superior. Arguments of counsel cannot take the place of factually supported objective evidence. See, e.g., In re Huang, 100 F.3d 135, 139-40, 40 USPQ2d 1685, 1689 (Fed. Cir. 1996); In re De Blauwe, 736 F.2d 699, 705, 222 USPQ 191, 196 (Fed. Cir. 1984). After review of the identified results, the examiner found this data provided is not commensurate in scope with the claimed invention. To establish unexpected results over a claimed range, applicants should compare a sufficient number of tests both inside and outside the claimed range to show the criticality of the claimed range. In re Hill, 284 F.2d 955, 128 USPQ 197 (CCPA 1960). For example, there is only a single fluorinated linear ether tested(1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether i.e. TTE) at a single percentage (70 vol. %) while claim 1 comprises any fluorinated linear ether at concentrations from 50-99 wt%. There are also only a very limited number of concentrations of the S-O based cyclic compounds included in the identified examples (0 ppm, 500 ppm and 5000 ppm) while a range of “greater than 0 and less than 1000 ppm” is claimed, which limits identification of unexpected and superior results. Finally, 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). MPEP §716.02(d). Applicant’s arguments with respect to Claim 1 have been considered but are moot because they address the amended Claim 1 and not the original Claim 1, see the rejection of newly amended claim 1 below. 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. Claims 1, 4, 6-11 are rejected under 35 U.S.C. 103 as being unpatentable over Youn et. al. (KR20190062969A, reference made to attached English translation), in view of Harada (WO2020090986A1, cited in IDS dated 11/30/23, reference made to English translation) and further in view of Nakajima (JP2019046759, cited in IDS dated 11/30/23, reference made to English translation). Regarding claims 1 and 4, Youn discloses a lithium-sulfur secondary battery comprising: a positive electrode (i.e. slurry coated in Al foil), a negative electrode, a separator; and an electrolyte (¶[0143]), but does not disclose a specific example wherein the electrolyte contains a S—O-based cyclic compound, and the S—O-based cyclic compound is ethylene sulfite, 1,3-propane sultone, 1,3-propene sultone, ethylene sulfate, or a combination thereof. Youn does disclose propene sultone may be chosen from a list of additives (¶[0112]). One of ordinary skill in the art would recognize modifying the electrolyte by adding propene sultone would to improve the high-temperature storage characteristics (¶[0112]). Therefore it would have been obvious to one of ordinary skill in the art to have added the propene sultone to the electrolyte to improve high-temperature storage characteristics.. Youn also discloses wherein the electrolyte further contains a non-aqueous solvent (i.e. methyltetrahydrofuran and ethylene glycol ethyl methyl ether) and a lithium salt (i.e. LiFSI) (¶[0143]). Youn does not disclose wherein the S—O-based cyclic compound is contained in the electrolyte in an amount of more than 0 ppm and less than 1,000 ppm based on the total weight of the electrolyte or wherein the non-aqueous solvent comprises a fluorinated linear ether in an amount of 50 wt. % to 99 wt. % based on the total weight of the non-aqueous solvent. Harada, related to lithium sulfur batteries, teaches a non-aqueous electrolyte which may contain additives including ethylene sulfite, propane sultone, propene sultone, and ethylene sulfate in a content ratio of preferably 0.01% (100 ppm) by mass or more preferably 0.1% (1000 ppm) by mass(¶[0127]). One of ordinary skill in the art would have recognized adding the propene sultone of Youn in the amount taught by Harada it would improve the capacity retention performance or charge/discharge cycle performance after high-temperature storage, and to improve safety. Therefore it would have been obvious to one of ordinary skill in the art to add 0.01-0.1 wt.% of propene sultone to the electrolyte of Youn to improve performance and safety. Nakajima, related to a lithium-sulfur secondary battery, teaches fluorinated linear ethers 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether(HFE) and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoropropyl ether (TFEE) (¶[0079], Table 1, see examples 1-4) at 1:12 and 1:20 mole ratios of tetraethylene glycol dimethyl ether : fluorinated linear ether. One of ordinary skill in the art would have recognized the fluorinated linear ether of Nakajima in the electrolyte solvent of Youn would provide increased capacity density (¶[0014]). Therefore, it would have been obvious to one of ordinary skill in the art to have used the fluorinated linear ether of Nakajima in the electrolyte solvent of Youn to provide increased capacity density 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). MPEP §2144.05. Regarding claim 6, modified Youn discloses a lithium-sulfur secondary battery according to claim 3, LiFSI (i.e. LiN(FSO2)2, ¶[0143]) as Experimental Example 1 and Youn further discloses LiSCN LiCl, LiBr, LiI, LiPF6, LiSbF6, LiAsF6, LiCF3SO3, LiCF3CO2, LiClO4, LiAlCl4, Li LiN (CF 3 SO 2) 3, LiN (FSO 2) 2, Lithium perchlorate as alternative lithium salt options. Regarding claim 7, modified Youn discloses a lithium-sulfur secondary battery according to claim 1, wherein the positive electrode comprises a positive electrode active material layer, and the positive electrode active material layer has a porosity of 62% (¶[0123]). Regarding claim 8, modified Youn discloses a lithium-sulfur secondary battery according to claim 1, wherein the positive electrode has a loading amount of a positive electrode active material of 5.5 mAh/cm2 (¶[0122]). Regarding claim 9 and 10, modified Youn discloses a lithium-sulfur secondary battery according to claim 1, wherein the sulfur-carbon composite on the positive electrode comprises 70 wt. % of sulfur based on the total weight of the sulfur-carbon composite (¶0121]). Regarding claim 11, modified Youn discloses a lithium-sulfur secondary battery according to claim 3, wherein the non-aqueous solvent further comprises a non-fluorinated linear ether (ethylene glycol ethyl methyl ether) and a cyclic ether (i.e. methyltetrahydrofuran) (¶0143]). Conclusion THIS ACTION IS MADE FINAL. 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 KAREN J. ARMSTRONG whose telephone number is (703)756-1243. The examiner can normally be reached Monday-Friday 10 am-6 pm EST. 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, Jeffrey Barton can be reached at (571) 272-1307. 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. /K.J.A./Examiner, Art Unit 1726 /JEFFREY T BARTON/Supervisory Patent Examiner, Art Unit 1726 10 October 2025
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Prosecution Timeline

Oct 10, 2022
Application Filed
May 15, 2025
Non-Final Rejection — §103
Aug 19, 2025
Response Filed
Oct 10, 2025
Final Rejection — §103
Jan 15, 2026
Request for Continued Examination
Jan 20, 2026
Response after Non-Final Action
Apr 09, 2026
Non-Final Rejection — §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
79%
Grant Probability
91%
With Interview (+11.9%)
3y 5m
Median Time to Grant
High
PTA Risk
Based on 19 resolved cases by this examiner. Grant probability derived from career allow rate.

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