Prosecution Insights
Last updated: April 19, 2026
Application No. 18/117,904

Prelithiated And Methods For Prelithiating An Energy Storage Device

Non-Final OA §103
Filed
Mar 06, 2023
Examiner
BARCENA, CARLOS
Art Unit
1723
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Enevate Corporation
OA Round
5 (Non-Final)
80%
Grant Probability
Favorable
5-6
OA Rounds
2y 10m
To Grant
93%
With Interview

Examiner Intelligence

Grants 80% — above average
80%
Career Allow Rate
883 granted / 1101 resolved
+15.2% vs TC avg
Moderate +12% lift
Without
With
+12.5%
Interview Lift
resolved cases with interview
Typical timeline
2y 10m
Avg Prosecution
38 currently pending
Career history
1139
Total Applications
across all art units

Statute-Specific Performance

§101
0.5%
-39.5% vs TC avg
§103
44.4%
+4.4% vs TC avg
§102
27.4%
-12.6% vs TC avg
§112
19.7%
-20.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1101 resolved cases

Office Action

§103
DETAILED ACTION In view of the Notice of Appeal filed on 02/09/2026, PROSECUTION IS HEREBY REOPENED. A new ground of rejection set forth below. To avoid abandonment of the application, appellant must exercise one of the following two options: (1) file a reply under 37 CFR 1.111 (if this Office action is non-final) or a reply under 37 CFR 1.113 (if this Office action is final); or, (2) initiate a new appeal by filing a notice of appeal under 37 CFR 41.31 followed by an appeal brief under 37 CFR 41.37. The previously paid notice of appeal fee and appeal brief fee can be applied to the new appeal. If, however, the appeal fees set forth in 37 CFR 41.20 have been increased since they were previously paid, then appellant must pay the difference between the increased fees and the amount previously paid. A Supervisory Patent Examiner (SPE) has approved of reopening prosecution by signing below: /TONG GUO/ Supervisory Patent Examiner, Art Unit 1723 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. 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 1-7, 16, and 18-24 are rejected under 35 U.S.C. 103 as being unpatentable over Sasaki et al. (US 5,556,721) in view of Stefan et al. (US 2012/0045670). Regarding claims 16, Sasaki teaches a nonaqueous electrode secondary battery comprising: a negative electrode with an active material represented by the formula LixSi, where x satisfies 0 ≤ x ≤ 5 (abstract); and wherein the prelithiation is from two kinds of methods (col. 4, line 54-col. 5, line 25). The starting material is silicon, “a delithiated silicon active material” since lithium (excess lithium) may be added. The absorption of lithium ions into silicon by the electrochemical reaction can be performed in the battery after assembly of the battery, or inside, or outside the battery during production (col. 5, line 27-30). Values of 0 ≤ x ≤ 5 would overlap Applicant’s claimed range of between 0% to about 30%. More specifically, Sasaki teaches a second method wherein using an electrochemical reaction between the silicon containing lithium and lithium or a material containing lithium, lithium ions are further absorbed by the silicon containing lithium (col. 4, line 67-col. 5, line 5). There is a given method (2) where the lithium or alloy of lithium conducts self-discharge, and lithium is electrochemically absorbed into the silicon of the substrate (col. 5, lines 54-57). This reads on the prelithiation of the silicon material performed before a first discharge of Si-based electrode and/or before a first formation cycle of the energy storage device. Moreover, Sasaki’s methods described in (1) and (3) also read on this claim limitation (col. 5, lines 27-64). However, Sasaki does not expressly teach the silicon active material is prelithiated to a level between 0% to about 30%. Stefan, directed to electrochemical cells containing high-capacity active material, teaches the additional lithium provided corresponds to between about 5% and 50% of the negative active material's theoretical capacity or, more specifically, to between about 5% and 25% of that capacity (para 0055; 0059). See MPEP 2144.05: Similar and Overlapping Range. It would have been obvious to one of ordinary skill in the art before the effective filing date to prelithiate to these levels in order to compensate for the irreversible lithium loss which may be determined experimentally (para 0059). Regarding claims 18-23, Sasaki teaches LixSi, where x satisfies 0 ≤ x ≤ 5 (abstract). See MPEP 2144.05. Regarding claims 7 and 24, an SEI layer is inherently present in the battery after at least the first cycle. Regarding claims 1-6, Sasaki teaches negative electrode 3 including LixSi, where x satisfies 0 ≤ x ≤ 5 (abstract), which would overlaps Applicant’s claimed range prelithiation level. Sasaki further teaches positive electrode 5, separator 4, and an electrolyte (Fig. 1; col. 11, lines 3-32). The absorption of lithium ions into silicon by the electrochemical reaction can be performed in the battery after assembly of the battery, or inside, or outside the battery during production (col. 5, line 27-30). More specifically, Sasaki teaches a second method wherein using an electrochemical reaction between the silicon containing lithium and lithium or a material containing lithium, lithium ions are further absorbed by the silicon containing lithium (col. 4, line 67-col. 5, line 5). There is a given method where the lithium or alloy of lithium conducts self-discharge, and lithium is electrochemically absorbed into the silicon of the substrate (col. 5, lines 54-57). This reads on the prelithiation of the silicon material performed before a first discharge of Si-based electrode and/or before a first formation cycle of the energy storage device. However, Sasaki does not expressly teach the silicon active material is prelithiated to a level between 0% to about 30%. Stefan, directed to electrochemical cells containing high-capacity active material, teaches the additional lithium provided corresponds to between about 5% and 50% of the negative active material's theoretical capacity or, more specifically, to between about 5% and 25% of that capacity (para 0055; 0059). See MPEP 2144.05: Similar and Overlapping Range. It would have been obvious to one of ordinary skill in the art before the effective filing date to prelithiate to these levels in order to compensate for the irreversible lithium loss which may be determined experimentally (para 0059). Claims 8-10, 17, 25-30 are rejected under 35 U.S.C. 103 as being unpatentable over Sasaki et al. (US 5,556,721) in view of Stefan et al. (US 2012/0045670) as applied to claims 1 and 16 above, and in further view of Howard et al. (US 2006/0093916). Regarding claims 8, 9, 17, and 25-29, Sasaki does not teach the electrolyte comprises at least some of the excess lithium. Howard, directed to a lithium-ion battery, teaches electrochemically active lithium may be added through a chemical or electrochemical process including the addition of butyl lithium (lithium source) in the electrolyte (para 0056). The electrochemically active lithium may be added through a chemical or electrochemical process; in another exemplary embodiment, the process may be an electrolytic process (para 0056) reading on the prelithiation of the silicon material performed before a first discharge of Si-based electrode and/or before a first formation cycle of the energy storage device. It would have been obvious to one of ordinary skill in the art before the effective filing date to use a different method to lithiate silicon to achieve the same. Regarding claims 10 and 30, Sasaki and Howard do not expressly teach amounts of the lithium additive. However, the amount of lithium additive is viewed as a result-effective variable where the amount of a strong lithiating agent such as metallic lithium or butyl lithium can be used to achieve the correct lithium stoichiometry. Claims 11 and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Sasaki et al. (US 5,556,721) in view of Stefan et al. (US 2012/0045670) as applied to claim 1 above, and in further view of Huang et al. (US 2007/0099084). Regarding claim 11, Sasaki does not teach a Si-dominant electrode. Huang, directed to a high-capacity electrode including an anode composite of LixSi (para 0028), teaches a silicon-based anode (para 0025). It would have been obvious to one of ordinary skill in the art before the effective filing date to have a Si-dominant electrode which result in high capacity after many cycles and good and stable electrical properties (para 0026-0027). Regarding claim 14, Huang teaches fluoroethylene carbonates (FEC) were included in cells (para 0029). It would have been obvious to one of ordinary skill in the art before the effective filing date to further include FEC which enhances the stability of the solid/electrolyte interface layer, and thus enhance the cycle life of the resultant battery (para 0029). Claim 12 and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Sasaki et al. (US 5,556,721) in view of Stefan et al. (US 2012/0045670) as applied to claim 1 above, and in further view of Park et al. (US 2011/0177393). Regarding claim 12, Sasaki does not teach a self-supporting composite material film. Park, directed to a composite material, teaches a self-supported composite structure (para 0033). It would have been obvious to one of ordinary skill in the art before the effective filing date to have a self-supported structure where the need for a metal foil current collector is eliminated or minimized (para 0033). Regarding claim 13, Park further teaches greater than 0% and less than about 90% by weight silicon particles, and greater than 0% and less than about 90% by weight of one or more types of carbon phases (abstract). Claim 15 is rejected under 35 U.S.C. 103 as being unpatentable over Sasaki et al. (US 5,556,721) in view of Stefan et al. (US 2012/0045670) and Huang et al. (US 2007/0099084), as applied to claim 14 above, in further in view of Lin et al. (Chem. Commun., 2012, 48, 7268–7270). Regarding claim 15, Sasaki, Stefan, and Huang do not further teach an electrolyte substantially free of non-fluorine containing cyclic carbonates. Lin, directed to high performance silicon nanoparticle anode in fluoroethylene carbonate-based electrolyte for Li-ion batteries, teaches 1 M LiPF6 in FEC/DMC (p. 7269, top left column; Fig. 1). It would have been obvious to one of ordinary skill in the art before the effective filing date to exclude non-fluorine containing cyclic carbonates since the capacity retention after cycling was significantly improved compared to electrodes cycled in a traditional ethylene carbonate (EC)-based electrolyte (abstract). Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to CARLOS BARCENA whose telephone number is (571)270-5780. The examiner can normally be reached Monday-Thursday 8-5 pm. 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, Tong Guo can be reached at (571)272-3066. 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. /CARLOS BARCENA/Primary Examiner, Art Unit 1723
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Prosecution Timeline

Mar 06, 2023
Application Filed
Sep 22, 2024
Non-Final Rejection — §103
Dec 23, 2024
Response Filed
Jan 16, 2025
Final Rejection — §103
Mar 07, 2025
Request for Continued Examination
Mar 10, 2025
Response after Non-Final Action
Mar 23, 2025
Non-Final Rejection — §103
Jun 27, 2025
Response Filed
Jul 02, 2025
Final Rejection — §103
Oct 07, 2025
Notice of Allowance
Oct 07, 2025
Response after Non-Final Action
Oct 30, 2025
Response after Non-Final Action
Feb 09, 2026
Response after Non-Final Action
Mar 01, 2026
Response after Non-Final Action
Mar 12, 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

5-6
Expected OA Rounds
80%
Grant Probability
93%
With Interview (+12.5%)
2y 10m
Median Time to Grant
High
PTA Risk
Based on 1101 resolved cases by this examiner. Grant probability derived from career allow rate.

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