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 .
Summary
Applicant’s arguments and claim amendments submitted December 3, 2025 have been entered into the file. Currently, claim 2 is canceled and claims 1 and 8 are amended, resulting in claims 1 and 3-11 pending for examination.
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.
Claims 1 and 9 are rejected under 35 U.S.C. 103 as being unpatentable over Wu (Wu, F. et al. Ionic liquid-based electrolyte with binary lithium salts for high performance lithium-sulfur batteries. Journal of Power Sources. 296, 10-17 (2015)) in view of Chen (US 2006/0210883 A1) and USDOE (US Department of Energy. Optimizing lithium-sulfur battery electrolytes for long life. May 24, 2018).
Regarding claim 1, Wu teaches a lithium-sulfur secondary battery (Li-S electrochemical cell, pg. 11 right column) comprising a positive electrode (cathode, pg. 11 right column), a negative electrode (lithium foil anode, pg. 11 right column), a separator (Celgard 2300 separator, pg. 11 right column), and an electrolyte containing lithium difluoro(oxalato)borate (Table 1 No. 6, LiODFB).
Wu Example No. 6 (Wu Table 1) teaches the amount of LiODFB being 11.5 ppm based on a total weight of the electrolyte (calculations shown below).
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Wu further teaches LiODFB amounts up to 29 ppm (Wu Table 1, calculations shown below).
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Wu does not teach the amount of LiODFB being within the range of 50 ppm or more and less than 1,000 ppm.
Wu further teaches that LiODFB forms the solid-electrolyte interphase (SEI) which protects the Li anode from lithium dendrites (Wu abstract). Wu teaches that “LiODFB can promote the SEI layer formation through reductive reactions, and the SEI layer prevents the shuttle effect and protects the Li anode in Li-S batteries” (Wu pg. 15 right column first paragraph).
Chen teaches non-aqueous electrolytes for secondary batteries (Chen title, abstract) and that electrode stabilizing additives such as lithium difluoro(oxalato)borate (Li[BF2(C2O4)], Chen [30]) that form a passivation film on the surface of the negative electrode “are typically present at a concentration of from about 0.001 to about 8 wt%” (Chen [31], 0.001 wt% x 10,000 = 10 ppm, 8 wt% x 10,000 = 80,000 ppm).
USDOE teaches that high salt concentrations in lithium-sulfur battery electrolytes can reduce ion mobility and result in insufficient ionic conductivity and that the salt/solvent ratio affects diffusion rates in the electrolyte (USDEO last paragraph).
Since Wu teaches that low concentrations of LiODFB are suitable, Wu and Chen both teach the use of LiODFB in electrolytes and that LiODFB forms a passivation layer on the anode of a rechargeable battery, Chen teaches that a concentration of 0.001 to about 8 wt% is suitable for passivation film forming additives, and USDOE teaches that the salt concentration impacts ion mobility and diffusion in the electrolyte, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to tune the amount of LiODFB added in the electrolyte of Wu, including amounts of 0.001 to about 8 wt% as taught by Chen, in order to obtain a lithium-sulfur battery with suitable performance characteristics and ion conductivity for a desired battery application.
The additive ppm (wt%) range of Chen substantially overlaps the claimed range in the instant claim 1. It has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by the prior art. See MPEP 2144.05 (I). 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 selected from the overlapping portion of the range taught by Chen, because overlapping ranges have been held to establish prima facie obviousness.
Regarding claim 9, Wu in view of Chen and USDOE teaches all features of claim 1, as described above. Wu further teaches the positive electrode (cathode) comprising a positive electrode active material that is a sulfur-carbon composite (MWCNT/S composite, pg. 11 right column).
Claims 7-8 are rejected under 35 U.S.C. 103 as being unpatentable over Wu in view of Chen and USDOE, as applied to instant claim 1 above, and in further view of Kang (Kang, N. Cathode porosity is a missing key parameter to optimize lithium-sulfur battery energy density. Nature Communications. 10, 4597 (2019)).
Regarding claim 7, Wu in view of Chen and USDOE teaches all features of claim 1, as described above. Wu further teaches the positive electrode comprising a positive elector active material layer (cathode mixture slurry spread on aluminum foil current collector, Wu pg. 11 right column). Wu is silent regarding the porosity of the positive electrode active material layer.
Kang teaches that the porosity of a sulfur-carbon composite cathode greatly impacts lithium-sulfur battery performance (Kang pg. 3 right column last paragraph) and porosity “plays a significant role in overall cell design because it determines the electrolyte quantity in the cell” (Kang pg. 7 left column). Kang further teaches that “the pore size and structure play an important role in the electrochemical performance of Li-S batteries due to the Li-PS dissolution associated redox shuttle reactions” (Kang pg. 2 left column last paragraph). Kang teaches that “electrodes with the porosity of 50-60% are suggested for a practical high-energy Li-S cell design” (Kang pg. 7 right column).
Since Kang teaches that cathode porosity can be tuned to improve performance of lithium sulfur batteries and that porosity values between 50% and 60% are suggested, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to tune the porosity of the positive electrode active material layer of Wu, including porosity values between 50% and 60% as taught by Kang, in order to obtain a cathode with suitable electrochemical performance for a desired battery application.
Regarding claim 8, Wu in view of Chen and USDOE teaches all features of claim 1, as described above. Wu is silent regarding the loading amount of the positive active material of the positive electrode (mAh/cm2).
Kang teaches that the electrolyte/solvent (E/S) ratio is affected by loading amount (areal capacity, mAh/cm2) and porosity of a positive electrode and that tuning the E/S ratio is a known method for optimizing battery performance (Kang pg. 7 left column).
Since Kang teaches that the loading amount of a positive electrode can impact battery performance, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to tune the loading amount of Wu, including amounts between 3.0 and 10.0 mAh/cm2, in order to obtain a battery with suitable performance for a desired battery application and achieve a desired E/S ratio.
Claims 3-6 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Wu in view of Chen and USDOE, as applied to instant claim 1 above, and in further view of Lu (Lu, H. et al. The enhanced performance of lithium sulfur battery with ionic liquid-based electrolyte mixed with fluorinated ether. Ionics. 25,2685-2691. Published online December 11, 2018).
Regarding claims 3-5, Wu in view of Chen and USDOE teaches all features of claim 1, as described above. Wu further teaches the electrolyte further comprising a non-aqueous solvent (Wu Table 1 No. 6, Pyr1,201 TFSI/TEGDME) and a lithium salt (LiTFSI, Wu Table 1 No. 6). Wu does not teach the non-aqueous solvent containing a fluorinated linear ether.
Lu teaches electrolytes for lithium sulfur batteries containing an ionic liquid, as taught in Wu, and further containing a fluorinated ether (Lu abstract), wherein the fluorinated ether is 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE, Lu abstract). Lu teaches that the fluorinated ether promotes ion conduction in the electrolyte, modifies and stabilizes the SEI on Li metal, reduces charge transfer impedance, and restricts dissolution and shuttle of polysulfides (Lu abstract), thus resulting in “high reversible capacity, good cycle, and rate capability” (Lu abstract).
Lu further teaches that TEGDME is an ether widely used in lithium sulfur batteries but suffers from low cycle efficiency due to polysulfide dissolution (Lu pg. 2685 right column).
Lu further teaches that fabricating a lithium sulfur cell wherein TTE comprises 50 wt% of the non-aqueous solvent results in improved and desirable battery performance (Lu conclusions, ET50 electrolyte Table 1).
Since Wu and Lu both teach electrolytes for lithium sulfur batteries containing ionic liquid and Lu teaches that the addition of a fluorinated ether (TTE) can improve lithium sulfur battery performance and that 50 wt% TTE is suitable, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to add TTE to the electrolyte of Wu, wherein the non-aqueous electrolyte comprises 50 wt% TTE based on a total weight of the non-aqueous solvent, in order to improve ion conduction and SEI stability, reduce charge transfer impedance, and restrict dissolution and shuttle of polysulfides.
Regarding claim 6, Wu in view of Chen, USDOE, and Lu teaches all features of claims 1 and 3, as described above. Wu further teaches the lithium salt being LiN(CF3SO2)2 (LiTFSI, Wu Table 1 No. 6).
Regarding claim 11, Wu in view of Chen, USDOE, and Lu teaches all features of claims 1 and 3, as described above. Wu further teaches the non-aqueous solvent further comprising a non-fluorinated ether (TEGDME, Wu Table 1 No. 6).
Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over Wu in view of Chen and USDOE, as applied to instant claim 1 above, and in further view of Kang and Li (Li, G. et al. Three-dimensional porous carbon composites containing high sulfur nanoparticle content for high-performance lithium-sulfur batteries. Nature Communications. 7, 10601 (2016)).
Regarding claim 10, Wu in view of Chen and USDOE teaches all features of claims 1 and 9, as described above. Wu further teaches the sulfur-carbon composite comprising 50 wt% sulfur based on a total weight of the sulfur-carbon composite (Wu pg. 11 right column, S content of 50 wt%) and that the composite material is made using a melt-diffusion process. Wu does not teach the sulfur-carbon composite comprising 60 wt% to 90 wt% sulfur.
Kang teaches a cathode for a lithium-sulfur battery comprising a sulfur-carbon composite (Ketjen Black/sulfur, Kang pg. 7 right column) formed by a melt-diffusion process, as used by Wu, wherein the sulfur-carbon composite comprises 80 wt% sulfur (Kang pg. 7 right column paragraph 3). Kang teaches that forming sulfur-carbon composites wherein sulfur infiltrates a carbon matrix is a known approach that can improve sulfur utilization and cycle stability and “can be easily scaled up to suppress diffusion of Li-PS and improve the transport of electrolyte” (Kang pg. 2 left column).
Li teaches the sulfur content in sulfur-carbon composites used for lithium-sulfur batteries should be tuned in order to achieve suitable specific capacity, cycling life, and sulfur utilization (Li pg. 2 left column). Li teaches that a sulfur content that is too high can result in larger sulfur particles that reduce the rate of sulfur utilization due to the long diffusion path for electrons and lithium ions, while a sulfur content that is too low results in reduced overall volumetric capacity and energy density of the cathode (Li pg. 2 left column).
Since Kang teaches that a sulfur content of 80 wt% is suitable and Li teaches that it is known to optimize sulfur content in cathode materials for lithium-sulfur batteries, 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 sulfur content in the sulfur-carbon composite of Wu, including sulfur contents between 60 wt% and 90 wt%, in order to obtain a positive electrode with suitable specific capacity, cycling life, and sulfur utilization for a desired battery application.
Response to Arguments
Response – Claim Rejections 35 USC § 112
The rejection of claim 8 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 is overcome due to applicant’s amendment to claim 8 in the response received December 3, 2025. This rejection of claim 8 is withdrawn.
Response – Claim Rejections 35 USC § 102 and 103
The rejections of claims 1 and 9 under 35 U.S.C. 102(a)(1) as being anticipated by Wu are overcome by applicant’s amendments to claim 1 in the response received December 3, 2025.
Applicant’s arguments filed December 3, 2025 have been fully considered and are not persuasive.
On pages 6-7 of the response, applicant appears to allege that the teachings of Chen regarding the wt% of LiODFB are not pertinent due to Chen disclosing LiODFB being used in a lithium metal oxide battery instead of a lithium-sulfur battery. On page 6 of the response, applicant states “the instant specification discloses that cycle performance of a lithium-sulfur secondary battery is improved when the claimed borate-based lithium salt is added to the electrolyte thereof, but the same advantageous effects would not be obtained with a general lithium secondary battery using lithium metal oxide as a positive electrode active material, which corresponds to the battery of Chen”.
These arguments are not persuasive. Chen provides a general teaching of a concentration range of LiODFB suitable for use in rechargeable batteries, Wu teaches that low LiODFB concentrations are suitable, and both Wu and Chen teach that LiODFB is used in rechargeable battery electrolytes and forms a passivation film that protects the anode, as described above for instant claim 1. Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to tune the amount of LiODFB according to the range disclosed by Chen, and in further view of the teaching of USDOE that the salt concentration impacts ion mobility and diffusion in a lithium-sulfur battery electrolyte, in order to obtain an electrolyte with suitable performance for a desired battery application.
On page 7 of the response, applicant states that “USDOE merely recites “lithium salt” but remains completely silent with respect to a borate-based lithium salt and an amount thereof”.
In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
USDOE provides a general teaching that high salt concentrations in lithium-sulfur battery electrolytes can reduce ion mobility and result in insufficient ionic conductivity and that the salt/solvent ratio affects diffusion rates in the electrolyte (USDEO last paragraph). Therefore, the USDOE reference provides motivation for tuning salt amounts in lithium-sulfur batteries in order to achieve sufficient ionic conductivity.
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.
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Zhang (US 2018/0076485 A1): appears to disclose fluorinated ether compounds for lithium-sulfur battery electrolytes (abstract) and an electrolyte containing LiTFSI, a fluorinated ether, and a non-fluorinated ether ([43]).
O’Neill (US 2015/0214577 A1): appears to disclose an electrolyte containing a fluorinated ether and lithium difluoro(oxalato)borate (Table 1, ID# 37 and 41).
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/J.S.C./Examiner, Art Unit 1789
/MARLA D MCCONNELL/Supervisory Patent Examiner, Art Unit 1789