Prosecution Insights
Last updated: April 19, 2026
Application No. 18/128,869

SILICA-COATED SULFUR-CARBON COMPOSITE AND LITHIUM-SULFUR BATTERY COMPRISING THE SAME

Non-Final OA §102§103
Filed
Mar 30, 2023
Examiner
LUSTGRAAF, BENJAMIN T
Art Unit
1727
Tech Center
1700 — Chemical & Materials Engineering
Assignee
LG Energy Solution, Ltd.
OA Round
1 (Non-Final)
65%
Grant Probability
Favorable
1-2
OA Rounds
3y 6m
To Grant
84%
With Interview

Examiner Intelligence

Grants 65% — above average
65%
Career Allow Rate
15 granted / 23 resolved
At TC average
Strong +19% interview lift
Without
With
+18.9%
Interview Lift
resolved cases with interview
Typical timeline
3y 6m
Avg Prosecution
37 currently pending
Career history
60
Total Applications
across all art units

Statute-Specific Performance

§103
55.5%
+15.5% vs TC avg
§102
23.6%
-16.4% vs TC avg
§112
16.1%
-23.9% vs TC avg
Black line = Tech Center average estimate • Based on career data from 23 resolved cases

Office Action

§102 §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 . Election/Restrictions Applicant’s election without traverse of Group I, claims 1-20 in the reply filed on 12/03/2025 is acknowledged. Claims 21-23 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 12/03/2025. Claim Rejections - 35 USC § 102 The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action: A person shall be entitled to a patent unless – (a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention. Claims 1, 4, 13, and 17-19 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Fan et al. (CN 105006553 A). Regarding claim 1, Fan discloses a silica-coated sulfur-carbon composite (paragraphs 0007, 0019, 0041), comprising: a sulfur-carbon composite; and silica particles coated on at least a portion of a surface of the sulfur-carbon composite (paragraph 0041, figure 3). Regarding claim 4, Fan discloses the limitations of claim 1. Fan further discloses that the silica particles are represented by Formula 1: [SiO2]p[SiO(OH)2]1-p, wherein 0<p≤1 (paragraphs 0019, 0041, silicon dioxide (SiO2), equivalent to the claimed formula when p=1). Regarding claim 13, Fan discloses a method for manufacturing a silica-coated sulfur-carbon composite, comprising: coating silica particles on at least a portion of a surface of a sulfur-carbon composite (paragraphs 0007, 0019, 0041, figure 3). Regarding claim 17, Fan discloses the limitations of claim 1. Fan further discloses a positive electrode active material comprising the silica-coated sulfur-carbon composite (paragraphs 0007, 0021, 0041). Regarding claim 18, Fan discloses the limitations of claim 1. Fan further discloses an electrode comprising the silica-coated sulfur-carbon composite (paragraph 0041). Regarding claim 19, Fan discloses the limitations of claim 1. Fan further discloses a lithium-sulfur battery, comprising: a positive electrode comprising the silica-coated sulfur-carbon composite; a negative electrode comprising a negative electrode active material; and an electrolyte solution (paragraphs 0004, 0041). 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. Claims 7, 16, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Fan et al. (CN 105006553 A). Regarding claims 7 and 16, Fan discloses the limitations of claim 1. Fan further discloses that a weight ratio of the sulfur-carbon composite and the silica particles in 99.9:0.1 to 80:20 (paragraph 0020, 50-90% sulfur, 5-20% carbon, 5-30% oxide which may be silicon dioxide, overlapping the claimed range). 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, 191USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). See also MPEP 2144.05. Regarding claim 20, Fan discloses the limitations of claim 1. Fan further discloses that the silica-coated sulfur-carbon composite comprises less than 10 parts by weight of silica particles based on 100 parts by weight of the silica-coated sulfur-carbon composite (paragraph 0020, 5-30% oxide which may be silicon dioxide, overlapping the claimed range). 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, 191USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). See also MPEP 2144.05. Claims 3 and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Fan et al. (CN 105006553 A) in view of Lai (US 20150061598 A1). Regarding claim 3, Fan discloses the limitations of claim 1. Fan is silent regarding wherein an average particle size (D50) of the silica particles is 10 nm to 50 nm. Lai discloses a lithium-sulfur cell comprising mesoporous silica particles which may be incorporated into a coating onto the surface of an article of the battery, wherein the article may be the positive electrode which may comprise a carbon-sulfur composite (Lai paragraph 0017). Lai further discloses that the average particle size of the particles included in the coating is about 5 to 2000 nanometers (Lai paragraph 0055, overlapping the claimed range). The reference teaches that the particles prevent sulfur loss and capacity degradation (Lai paragraphs 0034-0035). Lai and Fan are analogous because they both disclose lithium-sulfur cells with carbon-sulfur composites. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the coating disclosed by Fan to include particles of the size disclosed by Lai for the purpose of preventing sulfur loss and capacity degradation. Regarding claim 15, Fan discloses the limitations of claim 13. Fan is silent regarding wherein the coating step comprises mixing the sulfur-carbon composite with the silica particles in solid state. Lai discloses a lithium-sulfur cell comprising mesoporous silica particles which may be incorporated into a coating onto the surface of an article of the battery, wherein the article may be the positive electrode which may comprise a carbon-sulfur composite (Lai paragraph 0017). Lai further discloses that the particles are produced as a solid silica product and may be combined with a carbon-sulfur composite including elemental sulfur and carbon powder (paragraphs 0057, 0068, equivalent to mixing in a solid state as all components combined are solids). The reference teaches that the particles prevent sulfur loss and capacity degradation when included in an article such as the carbon-sulfur composite (Lai paragraphs 0034-0035). Lai and Fan are analogous because they both disclose lithium-sulfur cells with carbon-sulfur composites. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the composite disclosed by Fan to include the solid particles mixed with the composite as disclosed by Lai for the purpose of preventing sulfur loss and capacity degradation. Claims 5-6 are rejected under 35 U.S.C. 103 as being unpatentable over Fan et al. (CN 105006553 A) in view of Lloyd (US 20230387397 A1). Regarding claim 5, Fan discloses the limitations of claim 1. Fan is silent regarding wherein a coating thickness of the silica particles on the at least a portion of the surface of the silica- coated sulfur-carbon composite is 20 nm to 5 pm. Lloyd discloses a carbon-sulfur composite for a lithium-sulfur battery comprising a layer covering the exterior surface of the particles, wherein the coating layer may be silicon oxide (Lloyd paragraphs 0009, 0041-0043). Lloyd further discloses that the coating layer has a thickness of less than for example 25 nm to reach the desired area specific lithium ionic resistance (Lloyd paragraphs 0040, overlapping the claimed range). The reference teaches that the coating thickness prevents pin-holes and provides a high proportion of active component mass (Lloyd paragraph 0052). Lloyd and Fan are analogous because they both disclose lithium-sulfur batteries with silica-coated carbon-sulfur composites. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the coating disclosed by Fan to have the thickness disclosed by Lloyd for the purpose of reaching the desired area specific lithium ionic resistance, preventing pin-holes, and providing a high proportion of active material mass. Regarding claim 6, Fan discloses the limitations of claim 1. Fan does not explicitly disclose that the silica-coated sulfur-carbon composite satisfies formula 2. However, Fan does disclose that the composite comprises by mass 50-90% sulfur, 5-20% carbon, and 5-30% oxide which may be silicon dioxide (paragraph 0020). Lloyd discloses a carbon-sulfur composite for a lithium-sulfur battery comprising a layer covering the exterior surface of the particles, wherein the coating layer may be silicon oxide (Lloyd paragraphs 0009, 0041-0043). Lloyd further discloses that the coating layer may cover at least 90% of the surface area of the composite or up to the entire surface of the particles (Lloyd paragraph 0047). The reference teaches that ensuring a high percentage of the particles are coated maximizes benefits such as preventing dissolution of active material and degradation of the electrolyte (Lloyd paragraph 0052). Lloyd and Fan are analogous because they both disclose lithium-sulfur batteries with silica-coated carbon-sulfur composites. Considering a composition within the range disclosed by Fan of for example, 10 mass % of silica and 90 mass% of carbon and sulfur composite along with a coating area of silica particles of 95% as disclosed by Lloyd, Formula 2 is satisfied as follows: 10 m a s s % / ( 10 m a s s % + 90 m a s s % ) [ 95 % a r e a / 100 %   t o t a l   a r e a ] = 0.105 ,     0.0001 ≤ 0.105 ≤ 0.2 It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the coating disclosed by Fan to include the coating area disclosed by Lloyd in order to satisfy the claimed formula. Doing so would prevent degradation of the electrolyte. Regarding claim 8, Fan discloses the limitations of claim 1. Fan is silent regarding wherein an average particle size (D50) of the sulfur-carbon composite is 20 µm to 50 µm. Lloyd discloses a carbon-sulfur composite for a lithium-sulfur battery comprising a layer covering the exterior surface of the particles, wherein the coating layer may be silicon oxide (Lloyd paragraphs 0009, 0041-0043). Lloyd further discloses that the final particle size of the composite may be up to 50 µm or from 15 to 30 µm, substantially overlapping the claimed range (Lloyd paragraph 0028). The reference teaches that reduction to the final particle size may enable a more homogenous and dense electrode (Lloyd paragraph 0023). Lloyd and Fan are analogous because they both disclose lithium-sulfur batteries with silica-coated carbon-sulfur composites. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the composite disclosed by Fan to have the particle size disclosed by Lloyd. Doing so would provide a more homogenous and dense electrode. Regarding claim 9, Fan discloses the limitations of claim 1. Fan further discloses that sulfur is supported on the carbon material (paragraph 0041). Fan does not specifically disclose wherein the sulfur-carbon composite comprises a porous carbon material comprising a plurality of pores; and a sulfur-containing compound supported on at least a portion of inner and outer surfaces of the plurality of pores of the porous carbon material. Lloyd discloses a carbon-sulfur composite for a lithium-sulfur battery comprising a layer covering the exterior surface of the particles, wherein the coating layer may be silicon oxide (Lloyd paragraphs 0009, 0041-0043). Lloyd further discloses that the carbon-sulfur composite is formed of sulfur domains within a porous carbon host material. The sulfur material fills pores within the carbon material and may fill all pores within the carbon host structures (Lloyd paragraphs 0016, 0024). The reference teaches that this structure provides a high component of active mass (Lloyd paragraphs 0016, 0024). Lloyd and Fan are analogous because they both disclose lithium-sulfur batteries with silica-coated carbon-sulfur composites. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the composite disclosed by Fan to include the porous structure disclosed by Lloyd. Doing so would provide a high proportion of active mass. Regarding claim 10, modified Fan discloses the limitations of claim 9. Fan is silent regarding wherein an average diameter of the plurality of pores of the porous carbon material is 1 nm to 200 nm. Lloyd discloses a carbon-sulfur composite for a lithium-sulfur battery comprising a layer covering the exterior surface of the particles, wherein the coating layer may be silicon oxide (Lloyd paragraphs 0009, 0041-0043). Lloyd further discloses that the porous carbon may have an average pore diameter of less than 10nm, and preferably 1-3nm (Lloyd paragraph 0018). The reference teaches that the disclosed pore diameter may be beneficial in trapping sulfur within the pore structure (Lloyd paragraph 0051). Lloyd and Fan are analogous because they both disclose lithium-sulfur batteries with silica-coated carbon-sulfur composites. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the composite disclosed by Fan to include the pore diameter disclosed by Lloyd. Doing so would be beneficial in trapping sulfur within the pore structure. Regarding claim 11, modified Fan discloses the limitations of claim 9. Fan further discloses that the sulfur-containing compound comprises at least one of inorganic sulfur of chemical formula S8 (paragraph 0035, elemental sulfur, equivalent to S8). Regarding claim 12, modified Fan discloses the limitations of claim 9. Fan further discloses that a weight ratio of the porous carbon material and the sulfur-containing compound is 1:9 to 5:5 (paragraph 0020, 50-90% sulfur, 5-20% carbon, 5-30% oxide which may be silicon dioxide, substantially overlapping the claimed range). Regarding claim 14, Fan discloses the limitations of claim 13. Fan further discloses before the coating step: manufacturing the sulfur-carbon composite comprising mixing a sulfur-containing compound with a carbon material (paragraphs 009-0012). Fan is silent regarding the carbon material being porous. Lloyd discloses a carbon-sulfur composite for a lithium-sulfur battery comprising a layer covering the exterior surface of the particles, wherein the coating layer may be silicon oxide (Lloyd paragraphs 0009, 0041-0043). Lloyd further discloses that the carbon-sulfur composite is formed of sulfur domains within a porous carbon host material. The sulfur material is mixed with the porous carbon (Lloyd paragraph 0024). The reference teaches that this structure provides a high component of active mass (Lloyd paragraphs 0016, 0024). Lloyd and Fan are analogous because they both disclose lithium-sulfur batteries with silica-coated carbon-sulfur composites. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the composite disclosed by Fan to include the porous carbon disclosed by Lloyd. Doing so would provide a high proportion of active mass. Claims 2 is rejected under 35 U.S.C. 103 as being unpatentable over Fan et al. (CN 105006553 A) in view of Lai (US 20150061598 A1) and Lloyd (US 20230387397 A1). Regarding claim 2, Fan discloses the limitations of claim 1. Fan is silent regarding wherein an angle of repose of the silica-coated sulfur-carbon composite is equal to or less than 32°. It is deemed that the claimed angle of repose is an inherent characteristic and/or property of the specifically disclosed positive active material. In this respect, MPEP 2112 sets forth the following: Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). When the PTO shows a sound basis for believing that the products of the applicant and the prior art are the same, the applicant has the burden of showing that they are not. In re Spada, 911 F.2d 705, 709, 15 USPQ2d 1655, 1658 (Fed. Cir. 1990). “Products of identical chemical composition cannot have mutually exclusive properties.” A chemical composition and its properties are inseparable. Therefore, if the prior art teaches the identical chemical structure, the properties applicant discloses and/or claims are necessarily present. In re Spada, 911 F.2d 705, 709, 15 USPQ2d 1655, 1658 (Fed. Cir. 1990). In this case, the cited prior art teaches the claimed silica-coated carbon-sulfur composite, the silica particle size, the silica coating thickness, and the wight ratios of the claimed components. Therefore, considering the disclosed composite comprises substantially identical structure and particle size to the claimed configuration, the claimed angle of repose would necessarily be present and therefore the inherent property is rendered obvious in view of the prior art. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to BENJAMIN T LUSTGRAAF whose telephone number is (571)272-0165. The examiner can normally be reached Monday - Friday 8:30 am - 6:00 pm. 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, Barbara Gilliam can be reached at 571-272-1330. 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. /B.T.L./Examiner, Art Unit 1727 /BARBARA L GILLIAM/Supervisory Patent Examiner, Art Unit 1727
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Prosecution Timeline

Mar 30, 2023
Application Filed
Feb 18, 2026
Non-Final Rejection — §102, §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
65%
Grant Probability
84%
With Interview (+18.9%)
3y 6m
Median Time to Grant
Low
PTA Risk
Based on 23 resolved cases by this examiner. Grant probability derived from career allow rate.

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