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 . If status of the application as subject to 35 U.S.C. 102 and 103 is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
Status of Claims
Claims 1-4, 6-7, 9-15, 17, & 19-20 are pending in the application. Claims 9-15, 17, & 19-20 are withdrawn. Claims 1-4 & 6-7 are presently examined. Claims 1-8 were rejected in the 6/5/2026 office action.
Response to Amendment / Arguments
The 9/3/2026 amendment, in response to the 6/5/2026 office action, has been entered. Applicant’s claim amendments overcame the 35 U.S.C. 112(b) rejections. Applicant's arguments, regarding the 35 U.S.C. 103 rejections, have been fully considered but they are not persuasive.
Applicant argues:
“In particular, the Kim reference fails to teach or suggest performing a heat treatment, nor does it teach or suggest core crystallinity (FWHM) or the prevention of particle agglomeration.” Remarks p. 8.
In the prior office action, Examiner acknowledged that Kim fails to teach FWHM, but that Uesugi teaches a heat treatment resulting in the claimed FWHM. The claims don’t recite core crystallinity or prevention of particle agglomeration, so there is no requirement for the prior art to teach these.
Applicant argues:
“In addition, the Uesugi reference aims to suppress hydrogen sulfide gas generation and fails to teach or suggest a lithium-metal-oxide coating, core crystallinity, or particle agglomeration control.” Remarks p. 8.
It is unclear how Applicant’s argument, that “the Uesugi reference aims to suppress hydrogen sulfide gas generation” overcomes the 35 U.S.C. 103 rejection. Kim teaches the lithium-metal-oxide coating, so there is no need for the secondary reference (Usegui) to teach this. The claims don’t recite core crystallinity or particle agglomeration control, so there is no requirement for the prior art to teach these.
Applicant argues:
“In addition, as disclosed in paragraphs [0018] and [0039] of the Uesugi reference, the heat treatment in the Uesugi reference is explicitly designed to form a ‘non-argyrodite-type crystal structure’ (i.e., crystallization) on the coating layer. Therefore, the Uesugi reference explicitly teaches away from maintaining the surface coating layer in an amorphous state as recited in amended claim 1. Accordingly, one of ordinary skill in the art would have no motivation or reason to apply the heat treatment conditions of the Uesugi reference to the Kim reference.”
Examiner disagrees. Uesugi is directed to a sulfide-based solid electrolyte for maintaining lithium ion conductivity (abstract). Uesugi teaches heating a sulfide-based solid electrolyte at 100 °C to 300 °C (claim 7). It would have been obvious, to one of ordinary skill in the art, to apply this single concept, and to heat Kim’s solid electrolyte, as part of maintaining lithium ion conductivity in an electrolyte. There is no need for the secondary reference to teach all claim 1 limitations.
Furthermore, Uesugi’s teaching of a crystalline lithium compound (paragraphs 18 & 39) does not teach away from an amorphous lithium compound. Uesugi fails to state that an amorphous lithium compound is detrimental or undesirable.
Applicant argues:
“Finally, the claimed subject matter would not have been obvious, because the claimed solid electrolyte provides a surprising and unexpected improvement in properties. In particular, as described in paragraphs [0041], [0046], and [0050] of the present specification, the claimed solid electrolyte achieves a unique synergistic effect: the specific heat treatment increases the crystallinity of the core (FWHM) while keeping the surface oxide layer in an amorphous state, which successfully suppresses particle agglomeration and realizes a highly uniform particle size distribution (1 <(D90-D10)/D50≤5).” Remarks p. 9.
Examiner disagrees that Applicant has demonstrated unexpected results. Applicant failed to present experimental evidence of improved properties for the claimed limitations. Here are these limitations (in quotation marks) compared to these properties outside of these ranges:
“a full width at half maximum of a main peak is less than or equal to 0.160” compared to > 0.160;
“the lithium-metal-oxide is amorphous” compared to crystalline; and
“(D90-D10)/D50… is greater than 1 and less than or equal to 5” compared to ≤1 or >5.
Experimental based evidence of the superiority of the claimed ranges is needed to prove unexpected results.
Applicant argues:
“These features that flow from the claimed subject matter have not been shown to be taught, realized, or appreciated by the cited references.” Remarks p. 9.
MPEP 2144(IV) provides the law for this issue:
“The reason or motivation to modify the reference may often suggest what the inventor has done, but for a different purpose or to solve a different problem. It is not necessary that the prior art suggest the combination to achieve the same advantage or result discovered by applicant.”
Thus, there is no requirement that the prior art describe the present inventors’ discoveries of how the claimed solid electrolyte is beneficial. The prior art teaches the claimed solid electrolyte, and this is sufficient to reject the claims under 35 U.S.C. 103, even if the prior art failed to demonstrate the benefits discovered by the present inventors. A granted patent claim protects the claimed structure, but not the mental process used to conceive of that claimed structure.
Applicant argues:
“The outstanding Office action contends that the Kim reference teaches a solid electrolyte including 0.31 wt% to 46 wt% of a lithium metal oxide. Even assuming, arguendo, that the math is correct, which is not conceded, the claimed subject matter would not have been obvious, because the drastically narrower range of the instant claims provides a surprising and unexpected improvement in properties, relative to the significantly broader range from the Kim reference.” Remarks p. 9.
Examiner disagrees that Applicant has demonstrated unexpected results. See the discussion above regarding unexpected results.
Applicant argues:
“First, it is noted that the Kim reference completely fails to recognize any significance in the amount of lithium metal oxide included in the solid electrolyte. Accordingly, the beneficial properties that flow from the claimed subject matter are necessarily surprising and unexpected.” Remarks p. 9.
Whether or not the “beneficial properties that flow from the claimed subject matter” are unexpected is irrelevant. As discussed above, “It is not necessary that the prior art suggest the combination to achieve the same advantage or result discovered by applicant.” MPEP 2144(IV). See also the discussion above regarding evidence needed to overcome a 35 U.S.C. 103 rejection based on unexpected results.
Applicant argues:
“Second, the instant application provides clear evidence of the surprising and unexpected improvements in properties. Specifically, when the content of lithium-metal-oxide is the claimed range, the solid electrolyte may exhibit an appropriate particle size distribution without particle aggregation while realizing high ion conductivity. In particular, if the content of lithium-metaloxide satisfies the range of 0.01 wt% to 0.8 wt%, based on 100 wt% of the solid electrolyte, the surface of the sulfide-based solid electrolyte particles may be evenly coated with lithium-metaloxide. Accordingly, the ion conductivity and moisture stability of the solid electrolyte may be further improved, and the efficiency and cycle-life characteristics of the battery may be further
improved.” Remarks p. 10.
As discussed above, Applicant failed to present experimental evidence of improved properties inside of the claimed ranges compared to these properties outside of these ranges. Thus, Applicant failed to demonstrate unexpected results.
Applicant argues:
“Furthermore, nothing in any of the cited references would lead one of ordinary skill in the art to modify the teachings thereof to arrive at the claimed solid electrolyte” Remarks p. 10.
Examiner disagrees. For every combination of primary reference with a secondary reference, in the prior office action and in this office action, Examiner provided a motivation for the combination.
Regarding claim 7, Applicant argues:
“However, as may be seen in paragraph [0011] of the Maeyama reference, reproduced below in its entirety, increasing the energy density is explicitly a result of increasing the blend ratio of an active material in an electrode, and there is absolutely no indication that a D50 particle diameter of a solid electrolyte has any effect on the energy density, much less that a specific D50 particle diameter thereof would increase the energy density, as is contended in the outstanding Office action.” Remarks p. 12-13.
Examiner agrees that Maeyama doesn’t explicitly state that the increased energy density is a result of the D50 values. Patents frequently present an overall benefit, then teach the features of the invention, without stating which features cause the benefit. One of ordinary skill in the art, seeking increased energy density, would consult Maeyama and would learn Maeyama’s D50 values. It would then have been obvious to apply this teaching of Maeyama to Kim.
Applicant argues:
“As noted above, claim 7 recites, inter alia, "an average particle diameter (D50) of the solid electrolyte is 0.1 μm to 5.0 μm." The sulfide-based solid electrolyte particles having this particle size range can effectively penetrate between positive electrode active materials, and have excellent contact with the positive electrode active material and connectivity between solid electrolyte particles.6 These features flow from the presently claimed subject matter and are neither realized nor appreciated by the cited references.” Remarks p. 14.
As discussed above, “It is not necessary that the prior art suggest the combination to achieve the same advantage or result discovered by applicant.” MPEP 2144(IV).
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:
Determining the scope and contents of the prior art.
Ascertaining the differences between the prior art and the claims at issue.
Resolving the level of ordinary skill in the pertinent art.
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.
The claims are in bold font, the prior art is in parentheses.
Claims 1-4 are rejected under 35 U.S.C. 103 as being unpatentable over US20160322666A1 (Kim) in view of US20190312304A1 (Uesugi), US20200203757A1 (Park), and US20230299335A1 (Kitamura).
Kim teaches the following claim 1 limitations:
A solid electrolyte (abstract), comprising:
sulfide-based solid electrolyte particles (abstract: sulfide-based compound. paragraph 37 & figure 2: sulfide core 10); and
lithium-metal-oxide on surfaces of the sulfide-based solid electrolyte particles (Abstract: “an oxide-based lithium ion conductor on a sulfide-based compound”. Paragraph 13 lists specific oxide-based lithium ion conductor compounds. Paragraph 37 & figure 2: coating 30)
Claim 1 also states:
wherein in an X-ray diffraction analysis of the solid electrolyte, a full width at half maximum of a main peak is less than or equal to about 0.160
Kim fails to teach this analysis of the solid electrolyte.
The present specification and Uesugi provide additional guidance. The present specification teaches heating the solid electrolyte (paragraphs 21, 24-25, 28, 34, & 38-40). It is Examiner’s understanding that heating the solid electrolyte is the method Applicant uses to achieve the ≤ 0.160 full width half maximum x-ray diffraction value.
Uesugi is directed to a sulfide-based solid electrolyte for maintaining lithium ion conductivity (abstract). Uesugi teaches heating a sulfide-based solid electrolyte at 100 °C to 300 °C (claim 7). It would have been obvious, to one of ordinary skill in the art, before the effective filing date of the invention, to heat Kim’s solid electrolyte, as taught by Uesugi, as part of an electrolyte with maintained lithium ion conductivity.
Claim 1 also states:
the lithium-metal-oxide is amorphous
Kim teaches that the oxide-based lithium ion conductor can be Li2WO4 (paragraph 13). Kim, however, fails to teach whether Li2WO4 is crystalline or amorphous.
Park teaches that Li2WO4 inorganic solid electrolyte material can be amorphous (paragraph 97). Park is directed to a lithium secondary battery with improved energy efficiency (paragraphs 6 & 8-10). It would have been obvious, to one of ordinary skill in the art, before the effective filing date of the invention, for Kim’s Li2WO4 to be amorphous, as taught by Park, as part of a battery with improved energy efficiency.
Kim fails to teach the following limitation of claim 1, which is taught by Kitamura:
a value of (D90-D10)/D50 in a particle size distribution for the solid electrolyte is greater than about 1 and less than or equal to about 5 (Table 1: D10=1.18 μm, D50=2.67 μm, D90=5.53 μm. (5.53-1.18)/2.67=1.63)
Kitamura is directed to a sulfide solid electrolyte with sulfide solid electrolyte having a small oil absorption amount (abstract). It would have been obvious, to one of ordinary skill in the art, before the effective filing date of the invention, for Kim’s sulfide core 10 to have D10=1.18 μm, D50=2.67 μm, & D90=5.53 μm, as taught by Kitamura (Table 1), as part of a sulfide solid electrolyte with a small oil absorption amount (abstract).
With regard to claim 2, modified Kim teaches the limitations of claim 1 as discussed above. Kim also teaches the following limitation of claim 2:
the lithium-metal-oxide includes one or more of… W… (paragraph 13: “the oxide-based lithium ion conductor may comprise… Li2WO4”)
With regard to claims 3-4, modified Kim teaches the limitations of claim 1 as discussed above. Claims 3-4 state:
Claim 3
a content of the lithium-metal-oxide is about 0.01 wt% to about 3 wt%, based on 100 wt% of the solid electrolyte
Claim 4
a content of the lithium-metal-oxide is about 0.01 wt% to about 0.8 wt%, based on 100 wt% of the solid electrolyte
Kim teaches the following:
The oxide-based lithium ion conductor [claimed lithium-metal-oxide] can have 0.1 nm to 500 nm thickness (paragraph 11); and can be Li2WO4 (paragraph 13), which has density1 = 4.30 g/cm3.
The sulfide core [claimed sulfide-based solid electrolyte particles] can have diameter = 500 nm to 10 μm (paragraph 10); and can be Li6PS5Cl (paragraph 12), which has density2 = 1.64 g/cm3.
Based on the above information, Kim’s oxide-based lithium ion conductor is 0.31 wt% to 46 wt% of the solid electrolyte. Therefore, Kim’s 0.31 wt% to 46 wt% range overlaps the 0.01 wt% to 3 wt% (claim 3) and the 0.01 wt% to 0.8 wt% (claim 4) ranges. MPEP 2144.05 (II)(A) provides the law for this issue:
“In the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976)”
Given that Kim’s range is similar to and overlaps the claimed ranges, and further given the fact that no criticality is disclosed for the claimed ranges, the ranges in claims 3-4 are obvious variants of Kim’s range.
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over US20160322666A1 (Kim) in view of US20190312304A1 (Uesugi), as applied to claim 1, and further in view of US20220263122A1 (Nakayama). Kim fails to teach the following limitation of claim 6, which is taught by Nakayama:
the sulfide-based solid electrolyte particles include an argyrodite-type sulfide (paragraph 40)
Nakayama teaches argyrodite-type sulfide solid electrolyte for improved ion conductivity (paragraph 40). It would have been obvious, to one of ordinary skill in the art, before the effective filing date of the invention, for Kim’s sulfide core to include argyrodite-type sulfide, as taught by Nakayama, for improved ion conductivity.
Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over US20160322666A1 (Kim) in view of US20190312304A1 (Uesugi), as applied to claim 1, and further in view of US20210043918A1 (Maeyama). Kim fails to teach the following limitation of claim 7, which is taught by Maeyama:
an average particle diameter (D50) of the solid electrolyte is about 0.1 μm to about 5.0 μm (paragraph 231: D50=0.8 μm)
Maeyama is directed to increased solid-state battery energy density (paragraph 11). The solid electrolyte can be sulfide-based (paragraph 45) with sulfide-based particles having D50=0.8 μm (paragraph 231). It would have been obvious, to one of ordinary skill in the art, before the effective filing date of the invention, for Kim’s sulfide core 10 to have D50=0.8 μm, as taught by Maeyama, as part of a battery with increased energy density.
Conclusion
THIS ACTION IS MADE FINAL. 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 extension fee 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 date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ROBERT WEST whose telephone number is 703-756-1363 and email address is Robert.West@uspto.gov. The examiner can normally be reached Monday-Friday 10 am - 7 pm ET.
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, Allison Bourke can be reached at 303-297-4684.
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.
/R.G.W./Examiner, Art Unit 1721
/ALLISON BOURKE/Supervisory Patent Examiner, Art Unit 1721
1 https://next-gen.materialsproject.org/materials/mp-18902
2 https://next-gen.materialsproject.org/materials/mp-985592
Prosecution Insights