DETAILED ACTION
Claim Rejections - 35 USC § 112
The rejection of claim 7 under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, is withdrawn in view of Applicant’s amendment
Claim Rejections - 35 USC § 102
The rejection of claim(s) 1, 3-4, and 8-9 under 35 U.S.C. 102a1 as being anticipated by Park et al. (“Dendrite-Suppressed Lithium Plating from a Liquid Electrolyte via Wetting of Li3N”, Adv. Energy Mater., 1700732, 2017, pp 1-7) is withdrawn in view of Applicant’s amendments.
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 and 3-9 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 purpose of the Li3N layer is protect the Li surface and suppress dendrite growth (See paragraph at top left on p. 2). 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 necessary in order to optimize dendrite prevention. Determination of an optimal range 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.
Claim(s) 2 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 8/15/25 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 0.1-100 micron. Applicant cites the inventive example in the specification having a powder bed thickness of 5 micron as having higher capacity and better capacity retention as compared to
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 optimal prevention of dendrite formation. The example Applicant points to in the specification has been considered but does not provide evidence of non-obviousness. A single data point is not sufficient to establish the presence of an unexpected result across the breadth of the claimed range. Furthermore, it does not appear that the comparative examples are representative of the closest prior art to Park et al. because none of the comparative examples include an Li3N powder layer as taught by Park et al.
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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/Holly Rickman/Primary Examiner, Art Unit 1785
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