Prosecution Insights
Last updated: April 18, 2026
Application No. 17/685,751

Composite Separator and Electrochemical Device Using the Same

Final Rejection §103
Filed
Mar 03, 2022
Examiner
GARCIA, BETHANY CLAIRE
Art Unit
1721
Tech Center
1700 — Chemical & Materials Engineering
Assignee
SK Ie Technology Co. Ltd.
OA Round
4 (Final)
65%
Grant Probability
Moderate
5-6
OA Rounds
3y 5m
To Grant
99%
With Interview

Examiner Intelligence

Grants 65% of resolved cases
65%
Career Allow Rate
55 granted / 85 resolved
At TC average
Strong +36% interview lift
Without
With
+36.4%
Interview Lift
resolved cases with interview
Typical timeline
3y 5m
Avg Prosecution
43 currently pending
Career history
128
Total Applications
across all art units

Statute-Specific Performance

§103
55.5%
+15.5% vs TC avg
§102
19.8%
-20.2% vs TC avg
§112
22.4%
-17.6% vs TC avg
Black line = Tech Center average estimate • Based on career data from 85 resolved cases

Office Action

§103
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 . Response to Arguments Applicant's reply filed 2/10/2026 includes an amendments to the instant specifications and claims, as well as arguments corresponding to the new limitation in Claim 1. Applicant’s amendments to the specification are accepted. These amendments resolve the objection to the specification set forth in the previous action. Applicant’s amendments to the claims resolve all claim objections and 35 USC 112(b) rejections set forth in the previous action. Examiner notes addition of the inorganic particle identifier “C” brings clarity to the scope of the claimed invention, with a minor claim objection (see below). Applicant's arguments filed 2/10/2026 regarding Claim 1 has been fully considered and are persuasive. Examiner agrees the primary reference (Kim) does not teach or disclose the inorganic particle (C) of amended Claim 1. After an updated search and consideration, the claimed invention remains obvious, but under new grounds. See underlined portion of this action for updates to the rejection. Claim Objections Claim 1 is objected to because of the following informality: Claim 1 has been amended to include a group of inorganic particles “(C).” The elements Ag, Au, Cu, Al, and Si for (C) are listed twice (see lines 14 and 15 of amended Claim 1). Please remove one of the recitations of Ag, Au, Cu, Al, and Si for (C) in Claim 1. Appropriate correction is required. 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 1, 5-7, 9, 10, 12, 19, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Kim et al., US 20190288261 A1, and further in view of Xiao et al., US 20190229318 A. Regarding Claim 1, Kim discloses a composite separator (separator 100 [0017-0020, 0071], Fig. 2) comprising: a porous substrate (a) (separator substrate 110 having open-type pores 111 formed therein [0071], Fig. 2), wherein the porous substrate (a) is formed of one or more selected from the group consisting of high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultra-high molecular weight polyethylene, polypropylene, and copolymers thereof (HDPE, LDPE, LLDPE, UHMWPE, PP [0036]); a first multi-dimensional heterogeneous material-containing composite layer (b) that is stacked on one or both surfaces of the porous substrate (a) (first coating portions 120 are coated on the upper surface and the lower surface of a separator substrate 110 [0071, 0056], Fig. 2); and an inorganic particle layer (c) formed on the first multi-dimensional heterogeneous material-containing composite layer (b) (the second coating portions 130 are coated on the entireties of the outer surfaces of the first coating portions 120 [0072], the first coating portion and the second coating portion are provided separately [0027, 0057]; Fig. 2), wherein the inorganic particle layer (c) comprises inorganic particles (C) (material for preventing the generation of hydrofluoric acid, SiO2 [0029]) and an organic binder (PVdF-HFP [0057]), and does not comprise a one-dimensional inorganic material (B) (see inorganic particle layer composition [0028-0030, 0057]; layer 130 does not comprise any of the “inorganic particles (b)” listed in [0034]), wherein the first multi-dimensional heterogeneous material-containing composite layer (b) comprises inorganic particles (A) (inorganic particles (a) [0031-0032]) and the one-dimensional inorganic material (B) (inorganic particles (b) [0033]). PNG media_image1.png 182 458 media_image1.png Greyscale Kim – Fig. 2 The composite separator structure of Claim 1 comprises “an inorganic particle layer (c),” and therefore is not required to meet the following limitations of Claim 1: “a second multi-dimensional heterogeneous material-containing composite layer (d) formed on the first multi-dimensional heterogeneous material-containing composite layer (b),” “the second multi-dimensional heterogeneous material-containing composite layer (d) comprises inorganic particles (A) and a one-dimensional inorganic material (B),” and “an amount of the one-dimensional inorganic material (B) in the first multi-dimensional heterogeneous material-containing composite layer (b) is different from an amount of the one-dimensional inorganic material (B) in the second multi- dimensional heterogeneous material-containing composite layer (d).” Kim does not disclose the inorganic particle (C) is one or more of the claimed particles (C) required by Claim 1. However, this limitation is taught by Xiao. Xiao teaches a porous separator coating may comprise hydrofluoric acid (HF)-scavenging zeolite particles (porous separator 16 and crystalline aluminosilicate zeolite [0060-0090], Fig. 2). Xiao teaches the lattice spacing within the zeolite structure can be customized by varying the SiO2:Al2O3 ratio, and also teaches a SiO2:Al2O3 ratio less than 10 is preferred for increasing the HF scavenging capabilities of the separator ([0065-0070]). While the primary reference Kim does not disclose any mechanical or thermal benefits of the inorganic particle SiO2 as the inorganic particle (C), Xiao teaches in addition to being a HF scavenger, the zeolite particles can improve the mechanical properties and thermal stability of the separator ([0075]). Xiao, like Kim, teaches the HF is produced when an electrolyte comprising LiPF6 is used in a lithium-ion cell (See Xiao, [0074] and Kim, [0059]). Before the effective filing date of the present invention, it would have been obvious to a person of ordinary skill in the art to replace the inorganic particle of Kim (SiO2) with the aluminosilicate zeolite particle of Xiao, in the inorganic particle layer (c) of Kim, as Xiao teaches a zeolite particle comprising SiO2 and Al2O3 will function as a HF scavenger, and also improve the mechanical properties and thermal stability of the separator. Regarding Claim 5, modified Kim discloses all limitations set forth above. The composite separator of modified Kim comprises “an inorganic particle layer (c),” and is not required to meet the following limitation: “the amount of the one-dimensional inorganic material (B) in the second multi-dimensional heterogeneous material-containing composite layer (d) is larger than the amount of the first multi-dimensional heterogeneous material-containing composite layer (b).” Regarding Claim 6, modified Kim discloses all limitations set forth above. The composite separator of modified Kim comprises “an inorganic particle layer (c),” and is not required to meet the following limitation: “the amount of the one-dimensional inorganic material (B) in the second multi- dimensional heterogeneous material-containing composite layer (d) is smaller than the amount of the first multi-dimensional heterogeneous material-containing composite layer (b).” Regarding Claim 7, modified Kim discloses all limitations set forth above. Modified Kim discloses the inorganic particles (A) of the second multi-dimensional heterogeneous material-containing composite layer (d) comprises one or two or more selected from a metal oxide, a metal nitride, a metal carbide, a metal carbonate, a metal hydrate, and a metal carbonitride (Kim, metal oxide and metal carbide [0033], metal nitride [0034]). The composite separator of modified Kim comprises “an inorganic particle layer (c),” and is not required to meet the following limitation: “the inorganic particles (A) of the second multi-dimensional heterogeneous material-containing composite layer (d) comprises one or two or more selected from a metal oxide, a metal nitride, a metal carbide, a metal carbonate, a metal hydrate, and a metal carbonitride.” Regarding Claim 9, modified Kim discloses all limitations set forth above. Modified Kim discloses the first multi-dimensional heterogeneous material-containing composite layer (b) further contains an organic binder (Kim, [0035]). Regarding Claim 10, modified Kim discloses all limitations set forth above. The composite separator of modified Kim comprises “an inorganic particle layer (c),” and is not required to meet the following limitation: “the second multi-dimensional heterogeneous material-containing composite layer (d) further contains an organic binder.” Regarding Claim 12, modified Kim discloses all limitations set forth above. The composite separator of modified Kim comprises “an inorganic particle layer (c),” and is not required to meet the following limitation: “the second multi-dimensional heterogeneous material-containing composite layer (d) comprises an amount of the one-dimensional inorganic material (B) of 30 to 99.99 wt% with respect to 100 wt% of a total amount of the one-dimensional inorganic material B and the organic binder.” Regarding Claim 19, modified Kim discloses all limitations set forth above. Modified Kim discloses the separator may be used in an electrochemical device (Kim, secondary battery [0037]) that further comprises a cathode (Kim, [0038-0043]), an anode (Kim, [0044-0046]), and an electrolyte solution (Kim, [0018, 0059-0060]). Regarding Claim 20, modified Kim discloses all limitations set forth above. Modified Kim discloses the electrochemical device is a lithium secondary battery (Kim, secondary battery with lithium ion conductivity [0018, 0037, 0081], LiPF6 electrolyte [0059]). Claims 8, 11, 13-15, and 21 are rejected under 35 U.S.C. 103 as being unpatentable over modified Kim as applied to the claims above, and further in view of Hu et al., CN 105529425 B. Regarding Claim 8, modified Kim discloses all limitations set forth above. Modified Kim does not disclose “the first multi-dimensional heterogeneous material-containing composite layer (b) comprises an amount of the one-dimensional inorganic material (B) of 0.1 to 50 wt%, and an amount of the inorganic particles (A) of 50 to 99.9 wt%.” However, this limitation is taught by Hu. Hu teaches when a separator coating comprises an inorganic particle (inorganic ceramic powder, Al2O3 [0031-0034]), adding a one-dimensional inorganic material to the coating will change the structure of the coating, which will increase the strength, puncture resistance, thermal stability, and air permeability of the separator (one-dimensional nanomaterial, TiO2 nanorods [0029-0035, 0110]). Hu teaches the coating composition has 0.1 to 50 wt% of the one-dimensional inorganic material (11 wt% TiO2 nanorods; see Examiner’s Table 1 for calculations of slurry in Example 1 [0055]), and 50 to 99.9 wt% of the inorganic particles (84 wt% Al2O3 [0055]). Examiner notes the combination of Al2O3 and TiO2 is permitted by Kim’s first coating layer (inorganic particles (a) and (b) [0032-0033]). Before the effective filing date of the present invention, it would have been obvious to a person of ordinary skill in the art to replace modified Kim’s first coating layer with the coating layer of Hu, which comprises 0.1 to 50 wt% of the one-dimensional inorganic material (11 wt% TiO2 nanorods) and 50 to 99.9 wt% of the inorganic particles (84 wt% Al2O3), as Hu teaches the combination will increase the strength, puncture resistance, thermal stability, and air permeability of the composite separator. Example 1 Parts by weight wt % Al2O3 100 84% TiO2 Nanorods 11 9% PA 5.55 5% PEG 1.11 1% PVA 1.11 1% Total 118.77 100% Hu – Example 1 – All components PNG media_image2.png 422 1028 media_image2.png Greyscale Composite Separator of Modified Kim Regarding Claim 11, modified Kim discloses all limitations set forth above. Modified Kim does not disclose “the first multi-dimensional heterogeneous material-containing composite layer (b) comprises an amount of the one-dimensional inorganic material (B) of 30 to 99.99 wt% with respect to 100 wt% of a total amount of the one-dimensional inorganic material (B) and the organic binder.” However, this limitation is also taught by Hu. Hu teaches a separator coating comprises an inorganic particle ([0031-0034]), a one-dimensional inorganic material ([0029-0035]), and a binder ([0037-0039]). Hu teaches adding the binder increases cross-linking capabilities between the two inorganic materials, and also increases adhesiveness of the coating layer ([0037-0039]). Hu’s Example 1 uses an organic binder (polyacrylate emulsion “PA”), and TiO2 nanorods as the one-dimensional organic material (see Examiner’s calculation of the claimed weight percentages; PA is the binder/adhesive [0037-0039, 0047], PVA and PEG are dispersants and are not included in the calculation [0040]). Example 1 shows an amount of the one-dimensional inorganic material is 66 wt% with respect to 100 wt% of a total amount of the one-dimensional inorganic material and the organic binder. Before the effective filing date of the present invention, it would have been obvious to a person of ordinary skill in the art to have an amount of the one-dimensional inorganic material (B) be 30 to 99.99 wt% with respect to 100 wt% of a total amount of the one-dimensional inorganic material (B) and the organic binder, in the composite separator of Kim, as Hu teaches the binder adds adhesiveness to the separator coating, and shows a preferred example within the claimed range. Example 1 Parts by weight wt % TiO2 Nanorods 11 66% PA (binder) 5.55 34% Total 16.55 100% Hu – Example 1 – One-dimensional inorganic material and binder only Regarding Claim 13, modified Kim discloses all limitations set forth above. Modified Kim discloses all limitations set forth above. Kim does not disclose “the one-dimensional inorganic material (B) has a diameter of 1 nm to 100 nm and a length of 0.01 μm to 100 μm.” However, this limitation is also taught by Hu. Hu teaches a separator coating comprising a one-dimensional inorganic material ([0029-0036]), wherein the material has a diameter of 1 to 100 nm (5 nm to 800 nm [0028]; Example 1: 40 nm to 200 nm [0055]) and a length of 0.01 to 100 μm (500 nm to 50 μm [0028]; Example 1: 0.5 μm to 10 μm [0055]). Hu teaches the one-dimensional inorganic material combines with an inorganic material (small-particle ceramic [0032]) to create a network-like structure in the coating, which acts as a supporting framework and further improves the tensile strength, puncture resistance, and other mechanical properties and thermal stability of the separator ([0032]). Before the effective filing date of the present invention, it would have been obvious to a person of ordinary skill in the art to replace the one-dimensional inorganic material (B) of modified Kim with the one-dimensional inorganic material (B) of Hu, as Hu teaches a one-dimensional inorganic material within the claimed range creates a network-like structure that brings numerous benefits to a composite separator. Regarding Claim 14, modified Kim discloses all limitations set forth above. Modified Kim discloses the one-dimensional inorganic material (B) is a nanowire or a nanofiber (Hu, nanowires, nanorods, fibers [0035]) formed of one or two or more selected from a metal, carbon, a metal oxide, a metal nitride, a metal carbide, a metal carbonate, a metal hydrate, and a metal carbonitride (Hu, TiO2 nanorods [0035-0036]). Regarding Claim 15, modified Kim discloses all limitations set forth above. Modified Kim discloses the one-dimensional inorganic material (B) is one or two or more selected from boehmite, Ga2O3, SiC, SiC2, quartz, NiSi, Ag, Au, Cu, Ag-Ni, ZnS, Al2O3, TiO2, CeO2, MgO, NiO, Y2O3, CaO, SrTiO3, SnO2, ZnO, and ZrO2 (Hu, TiO2 nanorods [0035-0036]). Regarding Claim 21, modified Kim discloses all limitations set forth above. Modified Kim does not disclose “the inorganic particles (A) of the first multi-dimensional heterogeneous material-containing composite layer (b) have an average particle diameter of 0.001 μm to 20 μm.” However, Hu teaches a preferred particle size of inorganic particles in a separator layer. Hu teaches when a separator coating comprises an inorganic particle (inorganic ceramic powder, Al2O3 [0031-0034]), and a one-dimensional inorganic material (one-dimensional nanomaterial, TiO2 nanorods [0029-0035, 0110]), the coating will contribute to an increased strength, puncture resistance, thermal stability, and air permeability of the separator ([0029-0035, 0110]). Hu teaches the inorganic particle has a size of 0.005 μm to 0.250 μm, which makes the particle easy to disperse, and achieves a separator with a uniform porosity and coating thickness (5-250 nm [0027-0032]). Before the effective filing date of the present invention, it would have been obvious to a person of ordinary skill in the art to have the inorganic particles (A) have an average diameter within the 0.001 μm to 20 μm range, in the composite separator of Kim, as Hu teaches the inorganic particle should be small in order to make the particle easy to disperse, as well as achieve a separator with a uniform porosity and coating thickness. The composite separator of modified Kim comprises “an inorganic particle layer (c),” and is not required to meet the limitation “inorganic particles (A) of the second multi-dimensional heterogeneous material-containing composite layer (d) have an average particle diameter of 0.001 μm to 20 μm.” Claims 17 and 18 are rejected under 35 U.S.C. 103 as being unpatentable over modified Kim as applied to Claim 1 above, and further in view of Yoo et al., US 20150140404 A1. Regarding Claim 17, modified Kim discloses all limitations set forth above. Modified Kim discloses a polyolefin-based porous separator having a thickness ranging from about 5 μm to about 30 μm is typical for a lithium ion secondary battery (Kim, [0004]), but Kim does not disclose thickness of the composite separator is “5 µm to 100 µm” as claimed. However, this limitation is taught by Yoo. Yoo teaches a porous polyolefin-based separator is preferably 1 µm to 30 μm (porous substrate [0022-0025]; within Kim’s cited range), and is coated in a mixture of organic and inorganic particles (organic/inorganic complex [0026-0030, 0083]). Yoo teaches the porous substrate including the organic/inorganic coating has a thickness range of 0.1 µm to 50 µm ([0043]). Yoo teaches when the composite separator has a thickness less than 0.1 µm, the separator cannot adequately be filled with the liquid electrolyte, when the composite separator is thicker than 50 µm, there will likely be mechanical problems with the separator ([0043]). Before the effective filing date of the present invention, it would have been obvious to a person of ordinary skill in the art to optimize the thickness of the composite separator of modified Kim, and would have been motivated to do so, as Yoo teaches a separator too thin will not allow the separator to be filled with enough liquid electrolyte, but a separator too thick will lead to mechanical problems. Yoo’s thickness range (0.1 µm to 50 µm) is within the claimed range (5 µm to 100 µm). Regarding Claim 18, modified Kim discloses all limitations set forth above. Although modified Kim teaches the composite separator has pores (Kim, separator substrate 110 has open-type pores 111 formed therein [0071]), and a polyolefin-based porous separator having a thickness ranging from about 5 μm to about 30 μm is typical for a lithium ion secondary battery (Kim, [0004]), modified Kim does not teach “a pore size of the porous substrate is 0.001 μm to 10 μm, and a porosity of the porous substrate is 5% to 95%.” However, these limitations are taught by Yoo. Yoo teaches a porous polyolefin-based separator is preferably 1 to 30 μm (porous substrate [0022-0025]; within modified Kim’s cited range), and is coated in a mixture of organic and inorganic particles (organic/inorganic complex [0026-0030, 0083]). Yoo teaches the porous substrate has a pore diameter in a range of 0.01 μm to 50 μm, and a porosity range of 10% to 90% ([0025]). Yoo also teaches pore sizes and porosity should be optimized, as too small of a pore size/too low level of porosity will not allow the separator to be filled with the liquid electrolyte, but a pore size/level of porosity too large will lead to mechanical problems with the separator ([0043]). Before the effective filing date of the present invention, it would have been obvious to a person of ordinary skill in the art to optimize the pore size and porosity of the porous substrate, in the composite separator of modified Kim, and would have been motivated to do so, as Yoo teaches too small of a pore size/too low level of porosity will not allow the separator to be filled with the liquid electrolyte, but a pore size/level of porosity too large will lead to mechanical problems with the separator. Yoo’s pore size and porosity ranges overlap with the claimed ranges. 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. Any inquiry concerning this communication or earlier communications from the examiner should be directed to BETHANY C GARCIA whose telephone number is (571)272-2475. The examiner can normally be reached Mon-Fri, 0800 - 1730 MT. 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. 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. /BETHANY C GARCIA/Examiner, Art Unit 1721 /ALLISON BOURKE/Supervisory Patent Examiner, Art Unit 1721
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Prosecution Timeline

Mar 03, 2022
Application Filed
Oct 10, 2024
Non-Final Rejection — §103
Jan 14, 2025
Response Filed
Mar 14, 2025
Final Rejection — §103
Jun 18, 2025
Request for Continued Examination
Jun 25, 2025
Response after Non-Final Action
Nov 07, 2025
Non-Final Rejection — §103
Feb 10, 2026
Response Filed
Mar 30, 2026
Final Rejection — §103 (current)

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Expected OA Rounds
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