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
Applicant’s amendment and arguments filed 03/03/2026 have been fully considered. Claim(s) 6,21 and 25 is/are amended; claim(s) 9, 10 remain withdrawn; claims 26 and 27 are new; and claim(s) 8, 17-20, 22 has/have been canceled. Examiner affirms that the original disclosure provides adequate support for the amendment.
Upon considering said amendment and arguments, the previous rejections under 35 U.S.C. 103 set forth in the Office action mailed 12/03/2026 has/have been withdrawn. Applicant’s amendment necessitated the new grounds of rejection below.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 6-7,11-16,21,23-24 and 26-27 are rejected under 35 U.S.C. 103 as being unpatentable over Fan et al. (CN-109742323-A; see attached machine translation) in view of Florida International University (Diffusion in Solids; hereinafter “Florida”).
Regarding claims 6, 7, 21, Fan discloses a method of preparing an electrode assembly for an electrochemical cell that cycles lithium ions ([0002]) comprising heating a precursor electrode assembly (“lithium-plated copper foil”) comprising a current collector (101) and lithium metal film (103, “metallic lithium transition layer”) disposed on one or more surfaces of the current collector ([0071], FIG. 4), thus reading on limitations of claims 6, 21.
The heating causes lithium atoms from a lithium metal film to diffuse into a current collector to form a solid solution interface that chemically binds the current collector and the lithium metal film ([0075]) as claimed in claim 21.
Fan discloses a suitable heat treatment temperature range of 25-180 °C ([0064]), this temperature range being less than a melting point of lithium (180.5 °C), thus reading on claim 6 and overlapping with the scope of claims 7 and 21 reciting temperature ranges of 120-180 °C encompassed within Fan’s temperature range.
Furthermore, Fan notes that element diffusion at the solid solution interface improves the bonding strength of the electrode assembly (Fan [0064]). It is known in the art that the diffusion coefficient of solids increases with temperature (see Florida pp. 8 slide 2), such that a skilled artisan seeking to increase the diffusion speed would consider increasing the heat treatment temperature beyond 25 °C for this purpose. On the other hand, the maximum temperature of Fan’s method is necessarily limited to below the melting point of lithium, 180 °C (Fan [0064]).
As such, in seeking to provide a desired rate of diffusion in Fan’s method of preparing an electrode assembly without melting the lithium in the assembly, it would be obvious for one having ordinary skill in the art to select within the temperature ranges of 120-180 °C claimed in claims 7 and 21 encompassed within Fan’s treatment temperature range of 25-180 °C according to Fan’s disclosure and physical considerations known in the art (see Florida) with a reasonable expectation of successfully diffusing elements at the solid solution interface to improve the bonding strength (MPEP 2144.05 I).
Fan further discloses this temperature is maintained for 0.1 hours (i.e., 6 minutes) to 48 hours to allow element diffusion in the electrode assembly ([0064]), this range encompassing the ranges of 20 minutes to 3 hours claimed in claim 6 and 20 minutes to 2 hours claimed in claim 21 such that a skilled artisan would have routinely selected within the claimed ranges with a reasonable expectation of successfully preparing Fan’s electrode assembly (MPEP 2144.05 I).
Additionally, Fan’s heat treatment improves the bonding strength of the electrode assembly through causing element diffusion at the solid solution interface ([0064]). As such, at least some minimum duration (e.g., at least 6 minutes) would be necessary to allow a suitable amount of element diffusion to form or strengthen the solid solution interface. At the same time, it would be apparent to one of ordinary skill in the art that maintaining the temperature for an excessively long period of time (e.g., for 48 hours) would unnecessarily delay processing of the electrode assembly.
As such, in seeking to balance improving the bonding strength and conductivity between layers without excessively increasing the manufacturing time of the electrode assembly, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to optimize the temperature maintenance time within a range of 6 minutes to 48 hours according to considerations disclosed by Fan and apparent to one of ordinary skill in the art; encompassing the claimed ranges of 20 minutes to 3 hours claimed in claim 6 and 20 minutes to 2 hours claimed in claim 21 such that a skilled artisan would have selected within the encompassed range through routine optimization with a reasonable expectation of success, being within the suitable range of treatment durations disclosed by Fan (MPEP 2144.05 II).
As a result of Fan’s heating process, lithium atoms from the lithium metal film (“metal transition layer”) diffuse into the current collector during the heating forming a solid solution interface (“metal solid solution”) chemically binding the current collector and the lithium metal film (“lithium-containing film layer”) to form the electrode assembly ([0063-0064], [0075]), reading on limitations of claim 6, the lithium metal film chemically bound by the solid solution interface defining the electrode assembly (“composite lithium metal anode”) ([0075]), reading on limitations of claim 21.
Regarding claims 11, 23, 26-27, modified Fan discloses the method of claims 6, 21, wherein the lithium metal film (“metal transition layer”) has a suitable thickness within a range of at least 0.01 µm (10 nm) to provide a sufficient effect of the lithium metal film and at most 20 µm to avoid introducing too much inactive material due to excessive thickness ([0047]).
As such, in seeking to balance the above considerations, it would be obvious for one having ordinary skill in the art to optimize the thickness of the lithium metal film within a range of 10 nm to 20 µm according to Fan’s disclosure, overlapping with portions of the claimed range of 1-110 nm in claims 11 and 23, and encompassing the claimed range of 30-110 nm in claims 26-27, such that a skilled artisan would have selected within the overlapping portion or encompassed range through routine optimization under Fan’s disclosure. Such an optimization would be made with a reasonable expectation of success, as this range is within Fan’s disclosed suitable thickness range (MPEP 2144.05 II).
Regarding claim 12, modified Fan discloses the method of claim 11, wherein the method further comprises preparing the electrode assembly by disposing the ultrathin lithium metal film (“metal transition layer”) onto the one or more surfaces of the current collector using means of electrochemical deposition (i.e., electrodeposition), this method being disclosed within a list of suitable deposition methods including physical vapor deposition, chemical vapor deposition, mechanical laying, or melt coating ([0048]).
As a skilled artisan must select at least some method of depositing the ultrathin lithium metal film onto one or more surfaces of the current collector, where electrodeposition is one of a finite set of identified, predictable solutions within the ambit of one of ordinary skill in the art, it would be obvious for one having ordinary skill in the art to routinely explore the selection of an electrodeposition process as a method of depositing modified Fan’s ultrathin lithium metal film with a reasonable expectation of success (MPEP 2143 I. E).
Regarding claims 13, 14, modified Fan discloses the method of claim 11, wherein the average thickness is a first average thickness, and the ultrathin lithium metal film (103 “metallic lithium transition layer”) is a first lithium metal film ([0071]), thus reading on claim 13.
Fan’s method further comprises, prior to the heating process, layering a second lithium metal film (102, “lithium foil”) onto the ultrathin lithium metal film (103) of the current collector ([0073], FIG. 4). The heating process then forms solid solutions at contact points (i.e., interfaces) between the current collector, ultrathin lithium metal film, and second lithium metal film ([0063], [0075]), such that the solid solution interface is only present after the heating.
In other words, after the heating process forms the solid solution interface from the first lithium metal film, Fan’s second lithium metal film becomes disposed onto the solid solution interface, this reading on the scope of claim 13.
Modified Fan’s second lithium metal film further comprises a second average thickness of preferably 1-50 µm ([0063]), which is greater than the first average thickness (10-110 nm; see discussion of claim 11) thus reading on claim 13, and which falls within and reads on the claimed range of 1-100 µm in claim 14.
Regarding claims 15, 24, modified Fan discloses the method of claims 6, 23. A specific embodiment of Fan’s method uses an 8 µm thick current collector ([0071]), thereby rendering obvious or disclosing with sufficient specificity a collector thickness of 8 µm which is within the claimed range of 5-80 µm.
Fan further discloses that diffusion zones (i.e., solid solution interfaces) suitably between 0-5 µm thick are formed in layers of the electrode assembly including the current collector ([0063]), corresponding to a range of 0%-62.5% of the depth of the average thickness of this current collector, which encompasses the ranges of 0.05%-1.5% claimed in claims 15 and 24 such that a skilled artisan would have routinely selected within the claimed ranges with a reasonable expectation of successfully preparing Fan’s electrode assembly (MPEP 2144.05 I).
Additionally, Fan attributes solid solution interface formation to strengthening the precursor electrode assembly ([0063]), such that a skilled artisan would seek to form at least some amount (i.e., <0 µm) of solid solution interface.
On the other hand, it is known in the art according to Fick’s First Law that the rate of diffusion (i.e., diffusion flux J) is proportional to
J
=
-
D
d
C
d
x
, where concentration gradient dC/dx is the difference in concentration C across distance x, and increasing the diffusion distance x (i.e., the thickness of the solid solution interface where diffusion takes place) reduces the rate of diffusion (Florida, pp. 5-6). Consequently, a skilled artisan would consider reducing the desired solid solution interface thickness (x) from Fan’s maximum value of 5 µm to improve manufacturing efficiency by improving the rate of lithium diffusion during heat treatment.
As such, in seeking to balance sufficiently forming Fan’s solid solution interface and improving the manufacturing efficiency, it would be obvious for one having ordinary skill in the art to optimize the solid solution interface within a range of 0-5 µm according to Fan’s disclosure and Florida’s teaching. In doing so, the artisan would utilize 0%-62.5% of the depth of the average thickness of this current collector, encompassing the ranges of 0.05%-1.5% claimed in claims 15 and 24 such that a skilled artisan would have selected within the encompassed range through routine optimization with a reasonable expectation of success (MPEP 2144.05 II).
Regarding claim 16, modified fan discloses the method of claim 6 wherein the current collector comprises copper (“copper foil roll 101”, [0071]).
Claim 25 is rejected under 35 U.S.C. 103 as being unpatentable over Fan (CN-109742323-A) and Florida as applied to claim 21, further in view of Iwama et al. (US-20080220338-A1; cited in 12/03/2025 Office action).
Regarding claim 25, modified Fan discloses the method of claim 21, where the method further comprises removing the electrode assembly comprising the current collector and lithium metal film after heat treatment to form the solid solution interface ([0075]), which would inherently result in cooling the current collector and the lithium metal film from the heat treatment temperature to an ambient (cooling) temperature. While this inherent cooling step would necessarily comprise at least some measure of cooling speed, Fan fails to numerically indicate a rate of cooling.
Iwama is related in the art as a method of preparing an electrode assembly for an electrochemical cell that cycles lithium ions (Iwama [0010]) where a precursor electrode assembly is analogously heated to cause constituents of the current collector and active material film to diffuse into each other, which Iwama similarly recognizes as advantageous to strengthen adhesion in the electrode assembly ([0020], [0039]). However, Iwama simultaneously teaches a desirability the formation of excessive amounts of alloys at the solid solution interface during heat treatment, which lowers the cycle characteristics ([0140]); to prevent this effect, Iwama teaches rapidly cooling the precursor electrode assembly after heat treatment where an embodiment is cooled at 500 °C/min (8.3 °C/s) ([0123], [0140]).
As such, in seeking to avoid excessive alloying from forming in modified Fan’s electrode assembly and to preserve cycle characteristics, it would be obvious for one having ordinary skill in the art to select a cooling rate of 8.3 °C/s after heat treatment as taught and exemplified by Iwama, this rate being within the claimed range of 5-50 °C/s. Such a modification would be made with a reasonable expectation of success, as Fan and Iwama are directed to analogous methods of heat treating an electrode assembly, and as modified Fan’s method necessarily comprises at least some measure of cooling speed for optimization.
Response to Arguments
Claim 25 has been amended in the claims filed 03/03/2026 to resolve a typographic error (“lithium metal film”); as such, the objection to this claim in the Office action filed 12/03/2025 is withdrawn.
Applicant’s arguments with respect to rejection of claim(s) 6, 21, and the corresponding dependent claims as unpatentable under 35 U.S.C. 103 in over previously cited prior art Tuoriniemi et al., THERMAL CONTACT TO LITHIUM METAL, Dai et al., U.S. Pub. No. 2019/03 12255, Iwama et al. U.S. Pub. No. 2008/0220338, Roozeboom et al., U.S. Pub. No. 2025/0336976, an as evidenced by Rupp et al. LITHIUM DIFFUSION IN COPPER 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.
Withdrawal of the previous ground of rejection has been necessitated by Applicant’s amendment filed 03/03/2026.
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.
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/E.C./Examiner, Art Unit 1751
/JONATHAN G LEONG/Supervisory Patent Examiner, Art Unit 1751 4/13/2026
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