Prosecution Insights
Last updated: April 19, 2026
Application No. 18/278,866

METHOD OF PRODUCING LITHIUM SULFIDE

Non-Final OA §102§103§DP
Filed
Aug 25, 2023
Examiner
FIGUEROA, JOHN J
Art Unit
1763
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Mitsubishi Materials Corporation
OA Round
1 (Non-Final)
83%
Grant Probability
Favorable
1-2
OA Rounds
2y 11m
To Grant
92%
With Interview

Examiner Intelligence

Grants 83% — above average
83%
Career Allow Rate
902 granted / 1087 resolved
+18.0% vs TC avg
Moderate +9% lift
Without
With
+8.7%
Interview Lift
resolved cases with interview
Typical timeline
2y 11m
Avg Prosecution
24 currently pending
Career history
1111
Total Applications
across all art units

Statute-Specific Performance

§101
0.6%
-39.4% vs TC avg
§103
36.6%
-3.4% vs TC avg
§102
31.9%
-8.1% vs TC avg
§112
13.8%
-26.2% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1087 resolved cases

Office Action

§102 §103 §DP
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 . Priority Applicant's claim of priority under 35 U.S.C. 371 as a national stage entry of PCT/JP2022/009417 filed March 4, 2022, which claims priority to Japanese Application No. JP2021-035650 filed March 5, 2021, hereby acknowledged. Double Patenting The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969). A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP §§ 706.02(l)(1) - 706.02(l)(3) for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b). The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA /25, or PTO/AIA /26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/process/file/efs/guidance/eTD-info-I.jsp. Claims 1-4 are provisionally rejected on the ground of non-statutory double patenting as unpatentable over claims 1-5 of U.S. Serial No. 17/911,543 (‘543 app) published May 4, 2023. The claims of the ‘543 app have been amended during prosecution on May 5, 2025. The claims at issue are not identical in that the claims of the ‘543 app further limits the lithium sulfate raw material reactant to possessing a specified weight loss property and molar ratio, and wherein the reducing agent contains carbon. However, the two sets of claims are not patentably distinct from each other because they are both drawn to a method of producing lithium sulfide from lithium sulfate (reactant), wherein the method includes a step of heating the lithium sulfate reactant within a specified temperature range, and wherein the of lithium sulfate and a reducing agent are fed into a furnace where they are heated at specified temperature ranges, for example, between 750°C and 950°C, to obtain lithium sulfide. Thus, claims 1-4 are unpatentable over the claims of the ‘543 app. Claim Rejections - 35 USC § 102 The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action: A person shall be entitled to a patent unless – (a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale or otherwise available to the public before the effective filing date of the claimed invention. (a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention. 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. Claims 1-4 are rejected under 35 U.S.C. §103 and unpatentable over by Inamura (US 2023/0343996 A1 to Inamura et al., published October 26, 2023). This reference has an effective filing date of July 9, 2020 due to a claim of foreign priority. Inamura discloses a method for producing lithium sulfide possessing high purity from a raw material containing lithium and sulfur (e.g., lithium sulfate), wherein the method includes: combining/heating the raw material with a reductant containing a carbon element to obtain an intermediate; followed by a subsequent reducing of the intermediate using a reducing gas to obtain lithium sulfide; and wherein the first step can be performed at a temperature of from 700°C. to 850°C (abstract; [0008] to [0017]; [0019] to [0021]; claims 1, 4-7 and 11 of Inamura). Inamura further discloses that the pressure of the reducing gas in the reaction system can be atmospheric, or may be below/above atmospheric pressure, wherein usually satisfactory results are obtained by circulating the reducing gas in the reaction system under atmospheric pressure ([0045]; [0053]). Although Inamura may not expressly disclose examples of its method of producing lithium sulfite performed under the reduced pressure conditions recited in present independent claim 1 (0.05 MPa or less), however, it would have been within the purview of one skilled in the art at the time of filing of the presently claimed invention to optimize the temperature/pressure conditions of the reaction of the raw material/lithium sulfate with the reducing agent to obtain a preferred yield of the lithium sulfite compound. These temperature/pressure conditions can thus be arrived by routine optimization of these variables. See, In re Aller, 220 F.2d 454, 456 (CCPA 1955) ("where 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" (citations omitted)); Pfizer, Inc. v. Apotex, Inc., 480 F.3d 1348, 1368 (Fed. Cir. 2007) ("discovery of an optimum value of a result effective variable is ordinarily within the skill of the art" and thus usually obvious (citation omitted)). See MPEP §2144.05 II A. Thus, in the absence of substantive data/evidence of secondary considerations to the contrary, the present claims are unpatentable over Inamura. . Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Any inquiry concerning this communication or earlier communications from the examiner should be directed to JOHN J FIGUEROA whose telephone number is (571)272-8916. The examiner can normally be reached on 8:30 am -6:00 pm. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, JOSEPH DEL SOLE can be reached on 571-272-1130. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. 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. Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see http://pair-direct.uspto.gov. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /JOHN J FIGUEROA/Primary Examiner, Art Unit 1763 January 26, 2026
Read full office action

Prosecution Timeline

Aug 25, 2023
Application Filed
Jan 26, 2026
Non-Final Rejection — §102, §103, §DP (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

1-2
Expected OA Rounds
83%
Grant Probability
92%
With Interview (+8.7%)
2y 11m
Median Time to Grant
Low
PTA Risk
Based on 1087 resolved cases by this examiner. Grant probability derived from career allow rate.

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