DETAILED ACTION
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 4/17/26 has been entered.
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.
Claim(s) 1, 3-9 and 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Park et al. (“Dendrite-Suppressed Lithium Plating from a Liquid Electrolyte via Wetting of Li3N”, Adv. Energy Mater., 1700732, 2017, pp 1-7).
Park et al. disclose structure for use as a Lithium anode in a battery formed by depositing Li3N powder onto a layer of Li metal (claim 8) followed by roll-pressing the two (see first two paragraphs of the Results and Discussion section) forming a powder bed (see Figure 1). The reference is silent with regard to the thickness of the Li3N layer.
However, the reference teaches that the Li3N layer is formed by depositing particles on the surface of a Li layer and then removing excess powder in order to form a uniformly covered surface (see Figure 1 and results and discussion section, first paragraph). Thus, it would have been obvious and within the level of ordinary skill in the art prior to the effective filing date of the invention to determine an optimal thickness for the Li3N in order to uniformly cover the Li layer. Determination of an optimal value of a result effective variable would have required routine optimization in the absence of evidence of criticality associated with the claimed thickness range.
With regard to claim 3, Park et al. do not specifically disclose a “sprinkling” process for applying the powder to the Li metal layer. However, the reference does teach that the Li3N layer is formed via application of a powder to form a surface as shown in Figure 1 wherein the Li3N is scattered on the Li layer. This application of powder reads on the claimed “sprinkling” step.
With regard to claim 4, Park et al. disclose that the Li3N powder and Li metal layer are “roll-pressed.” Thus, the layers would necessarily be under pressure between rolling plates during pressing.
With regard to claim 5, Park et al. does not specifically disclose what material is used for the rolling plates of the roll-press machine used therein. However, it would have been obvious to one of ordinary skill in the art to choose from any conventionally known roll-press machine in the electrode art including those with metal or polymer plates.
With regard to claims 6-7, Park et al. disclose a roll-press step in forming a lithium anode material but do not specifically disclose the temperature or force used during the process. It is noted that the claimed temperature range includes room temperature. It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to carry out the roll-press step taught by Park et al. at room temperature in the absence of a specific teaching of heating the surface. Furthermore, it would have been obvious to one of ordinary skill in the art to determine the optimal force and temperature conditions required for roll-pressing the two layers together in order to achieve optimal adhesion and density of the Li3N particles to the Li metal surface.
With regard to claim 9, the reference requires that the manufactured lithium metal negative electrode is “suitable for use as a lithium-sulfur battery.” This limitation does not impart and additional process, structure or composition to the method of claim 1. Thus, the limitation has been interpreted to be an intended use. The method taught by Park et al. is substantially the same as claimed and therefore, would be considered to be capable of meeting the intended use of claim 9 even though the reference does not specifically mention this use.
With regard to claim 20, Park does not disclose the presence of a binder in the Li3N powder bed. Instead, the reference discloses only the presence of Li3N powder (see Experimental section on p. 6).
Claim(s) 2 and 19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Park et al. (“Dendrite-Suppressed Lithium Plating from a Liquid Electrolyte via Wetting of Li3N”, Adv. Energy Mater., 1700732, 2017, pp 1-7) in view of Baloch et al. (“Variations on Li3N protective coating using ex-site and in-site techniques for Li0 in sulphur batteries”, Energy Storage Materials, 9 (2017) 141-149).
Park et al. disclose all of the features of claim 1, as set forth above, but fail to disclose the size of the Li3N particles used therein.
Baloch et al. discloses an ex situ technique for forming a Li3N protective layer on a Li metal layer for an anode. The reference teaches pressing Li3N powder to form a porous Li3N layer on a Li metal film (see Scheme I(i) on p 142). The reference also teaches that the porosity of the powder layer can allow for the passage of polysulfides towards the Li metal layer in a LiS system (see p 144, second paragraph in right column). Thus, determination of the appropriate particle size would have been obvious in order to optimize the porosity of the resultant particle layer taught by Park et al. and thereby control exposure of the Li metal surface to undesired surface reactions.
Response to Arguments
Applicant's arguments filed 4/17/26 have been fully considered but they are not persuasive. Applicant argues that the prior art of record fails to teach or suggest the newly claimed limitation requiring a thickness of 0.1-5 micron. Applicant cites the inventive example 2 in the specification having a powder bed thickness of 5 micron as having higher capacity and better capacity retention as compared to the comparative examples.
This argument is not persuasive because Applicant’s comparative examples do not represent the closest prior art to Park. Therefore, an evaluation of unexpected results associated with the claimed thickness range is not possible. More specifically, it is noted that the comparative example 2 lacks the presence of a Li3N layer entirely and thus, does not represent Park which includes a Li3N layer. Comparative example 4 includes a Li3N layer with a thickness of 5 µm (i.e., not outside the claimed range) but also includes a polymer binder which is not present in the Park reference. There is no comparative data showing that a Li3N layer having a thickness outside of the claimed range is unexpectedly different than the thickness of 5 µm shown in Examples 1 and 2. Nor is there data to show that values as low as 0.1 µm would show an unexpected improvement compared to thicknesses below the claimed range.
It is the Examiner’s contention that it would have been obvious to optimize the thickness of the Li3N powder bed taught by Park et al. in order to achieve uniform coverage of the Li layer in the absence of a showing of unexpected results associated with the claimed thickness range.
With regard to Applicant’s arguments that the claimed thickness range is critical, it has been held that arguments presented by the applicant cannot take the place of evidence in the record. In re Schulze, 346 F.2d 600, 602, 145 USPQ 716, 718 (CCPA 1965) and In re De Blauwe, 736 F.2d 699, 705, 222 USPQ 191, 196 (Fed. Cir. 1984).
With regard to Applicant’s arguments regarding the newly presented claims 19 and 20, claim 19 is met for the reasons set forth in paragraph 4, above. Claim 20 is met by Park because the reference does not include a binder in their Li3N powder layer, as noted in paragraph 3, above.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to HOLLY RICKMAN whose telephone number is (571)272-1514. The examiner can normally be reached Mon, Tues, Thurs, 9am-3pm EST.
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/Holly Rickman/Primary Examiner, Art Unit 1785
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