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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 9/15/2025 has been entered.
Response to Amendment
In the amendment dated 9/15/25, the following has occurred: Claims 1 and 20 were amended; Claims 8-9 were cancelled.
Claims 1-7 and 10-20 are pending. This communication is a Non-Final Rejection in response to the "Amendment" and "Remarks" filed on 9/15/25.
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 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 considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. 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.
Claims 1-7 and 10-20 are rejected under 35 U.S.C. §103 as being unpatentable over CN 103779544 A (“CN ’544”) in view of US 2018/0269475 A1 (“US ’475”).
As to Claim 1:
CN ’544 discloses:
a negative active material for a rechargeable lithium battery, as CN ’544 teaches a porous silicon/carbon composite material used as a negative electrode active material for a lithium-ion battery (Abstract; [0011], [0029]–[0031]);
a core comprising porous silicon, as porous silicon is produced by thermal decomposition of magnesium silicide followed by acid treatment, yielding a porous silicon structure ([0011], [0029]; Fig. 1);
a carbon layer on a surface of the core, as an organic carbon source is decomposed during heat treatment to form a carbon layer coating the surface of the porous silicon ([0020]–[0024]; Fig. 2); and
the porous silicon comprises pores having a size of about 100 nm, as SEM characterization describes the porous silicon as having a pore size of about 100 nm ([0040]).
However, CN ’544 does not disclose that the negative active material comprises about 1 wt% to about 12 wt% of magnesium based on 100 wt% of the total weight of the negative active material, because CN ’544 teaches that magnesium derived from magnesium silicide is oxidized and removed during acid etching and thus is not retained in the final porous silicon/carbon composite ([0017]–[0019]).
US ’475 discloses silicon-based negative active materials that retain magnesium in the final material, specifically teaching magnesium-containing compounds such as magnesium silicate (e.g., MgSiO₃, Mg₂SiO₄) incorporated in silicon-based negative electrode active materials ([0022], [0027]–[0030]). US ’475 further discloses that magnesium may be present in an amount that overlaps the claimed range of about 1 wt% to about 12 wt% based on the silicon-based negative active material ([0022]). Thus, US ’475 teaches the retention of magnesium in a silicon-based negative active material in the claimed wt% range, supplying the limitation not disclosed by CN ’544.
CN ’544 and US ’475 are analogous arts because both references are directed to silicon-based negative active materials for rechargeable lithium batteries and address common technical problems associated with silicon anodes, including structural stability, cycle life, and electrochemical performance.
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to modify the porous silicon/carbon composite negative active material of CN ’544 to retain magnesium in an amount of about 1 wt% to about 12 wt%, as taught by US ’475, in order to improve structural stability and electrochemical performance of the silicon-based negative active material, while maintaining the porous silicon structure, carbon coating, and pore size disclosed by CN ’544.
As to Claim 2:
CN ’544 does not disclose that magnesium is present in the final negative active material in an amount of about 1 wt% to about 10 wt% based on 100 wt% of the total weight of the negative active material, because CN ’544 teaches that magnesium derived from magnesium silicide is oxidized and removed during acid etching and therefore is not retained in the final porous silicon/carbon composite ([0017]–[0019]).
US ’475 discloses silicon-based negative active materials in which magnesium is retained, specifically teaching magnesium-containing compounds such as magnesium silicate (e.g., MgSiO₃, Mg₂SiO₄) incorporated in silicon-based negative electrode active materials ([0022], [0027]–[0030]). US ’475 further discloses magnesium contents in ranges that overlap about 1 wt% to about 10 wt% of the negative active material, thereby teaching the specific magnesium content.
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to modify the porous silicon/carbon negative active material of CN ’544 to retain magnesium in an amount of about 1 wt% to about 10 wt%, as taught by US ’475, in order to improve the stability and cycling performance of the silicon-based negative active material, while maintaining the porous silicon structure and carbon coating disclosed by CN ’544.
As to Claim 3:
CN ’544 does not disclose that magnesium is present in the final negative active material in an amount of about 3 wt% to about 10 wt% based on 100 wt% of the total weight of the negative active material, because CN ’544 teaches that magnesium derived from magnesium silicide is oxidized and removed during acid etching and therefore is not retained in the final porous silicon/carbon composite ([0017]–[0019]).
US ’475 discloses silicon-based negative active materials in which magnesium is retained, specifically teaching magnesium-containing compounds such as magnesium silicate (e.g., MgSiO₃, Mg₂SiO₄) incorporated in silicon-based negative electrode active materials ([0022], [0027]–[0030]). US ’475 further discloses magnesium contents in ranges that overlap the claimed range of about 3 wt% to about 10 wt%, thereby teaching the specific magnesium concentration.
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to modify the porous silicon/carbon negative active material of CN ’544 to retain magnesium in an amount of about 3 wt% to about 10 wt%, as taught by US ’475, as a matter of routine optimization of magnesium content to improve the stability and cycling performance of the silicon-based negative active material, while maintaining the porous silicon structure and carbon coating disclosed by CN ’544.
As to Claim 4:
CN ’544 does not disclose that magnesium is comprised in the negative active material as a MgSiO₃ compound, because CN ’544 teaches that magnesium derived from magnesium silicide is oxidized and removed during acid etching and therefore is not retained in the final porous silicon/carbon composite ([0017]–[0019]).
US ’475 discloses silicon-based negative active materials in which magnesium is retained as magnesium silicate, explicitly teaching magnesium-containing compounds such as MgSiO₃ incorporated in silicon-based negative electrode active materials to improve stability and electrochemical performance ([0022], [0027]–[0030]). Thus, US ’475 teaches the specific form of magnesium.
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to modify the porous silicon/carbon negative active material of CN ’544 to retain magnesium in the form of MgSiO₃, as taught by US ’475, in order to improve the stability and cycling performance of the silicon-based negative active material, while maintaining the porous silicon structure and carbon coating disclosed by CN ’544.
As to Claim 5:
CN ’544 does not explicitly disclose that the carbon layer comprises amorphous carbon, as CN ’544 describes formation of a carbon layer from thermal decomposition of an organic carbon source without expressly characterizing the carbon as amorphous ([0020]–[0024]).
US ’475 discloses silicon-based negative active materials having a carbon coating comprising amorphous carbon, expressly teaching that the carbon layer formed on silicon-based negative electrode materials may be amorphous carbon to improve conductivity and structural stability ([0024], [0027], [0031]). Thus, US ’475 teaches the specific carbon form.
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to modify the porous silicon/carbon negative active material of CN ’544 such that the carbon layer comprises amorphous carbon, as taught by US ’475, in order to improve electrical conductivity and cycling performance of the silicon-based negative active material, while maintaining the porous silicon structure and carbon coating disclosed by CN ’544.
As to Claim 6:
CN ’544 does not disclose that the amorphous carbon comprises soft carbon, hard carbon, or combinations thereof, as CN ’544 describes formation of a carbon layer from thermal decomposition of an organic carbon source without specifying whether the resulting amorphous carbon is soft carbon, hard carbon, or a combination thereof ([0020]–[0024]).
US ’475 discloses silicon-based negative active materials having carbon coatings comprising amorphous carbon, and expressly teaches that such amorphous carbon coatings may comprise soft carbon, hard carbon, or combinations thereof to improve conductivity and mechanical stability of silicon-based negative electrode materials ([0024], [0027], [0031]). Thus, US ’475 teaches the specific carbon types.
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to modify the porous silicon/carbon negative active material of CN ’544 such that the amorphous carbon layer comprises soft carbon, hard carbon, or combinations thereof, as taught by US ’475, as a matter of routine design choice to optimize electrical conductivity and cycling stability of the silicon-based negative active material, while maintaining the porous silicon structure and carbon coating disclosed by CN ’544.
As to Claim 7:
CN ’544 does not disclose that the carbon layer is present in an amount of about 5 wt% to about 45 wt% based on 100 wt% of the total amount of the negative active material, as CN ’544 describes formation of a carbon layer from an organic carbon source without specifying the carbon content in terms of wt% relative to the total negative active material ([0020]–[0024]).
US ’475 discloses silicon-based negative active materials having a carbon coating and expressly teaches that the carbon coating may be present in an amount that overlaps about 5 wt% to about 45 wt% of the total silicon-based negative active material in order to improve conductivity and structural stability ([0022], [0024], [0031]). Thus, US ’475 teaches the specific carbon-content range.
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to modify the porous silicon/carbon negative active material of CN ’544 such that the carbon layer is present in an amount of about 5 wt% to about 45 wt%, as taught by US ’475, as a matter of routine optimization to balance electrical conductivity and mechanical stability of the silicon-based negative active material, while maintaining the porous silicon structure and carbon coating disclosed by CN ’544.
As to Claim 10:
CN ’544 further discloses that the negative active material is prepared by heat-treating magnesium silicide to obtain a treated product ([0015]–[0016]); etching the heat-treated product to remove magnesium-containing phases and form porous silicon ([0017]–[0019]); mixing the porous silicon with a carbon source to form a mixture ([0020]–[0022]); and heat-treating the mixture to carbonize the carbon source and form a carbon layer on the porous silicon ([0022]–[0024]).
However, CN ’544 does not disclose that the carbon precursor used in the mixing step is an amorphous carbon precursor, nor does CN ’544 explicitly disclose that the resulting carbon layer is derived from an amorphous carbon precursor.
US ’475 discloses silicon-based negative active materials prepared using amorphous carbon precursors, and expressly teaches mixing silicon-based materials with amorphous carbon precursors followed by heat treatment to form amorphous carbon coatings on silicon-based negative electrode active materials ([0024], [0027], [0031]). Thus, US ’475 teaches the use of an amorphous carbon precursor in a preparation process corresponding to the step not disclosed by CN ’544.
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to modify the preparation method of the porous silicon/carbon negative active material of CN ’544 by using an amorphous carbon precursor during the mixing step, as taught by US ’475, and subsequently heat-treating the mixture, in order to form an amorphous carbon layer on the porous silicon and thereby improve conductivity and cycling performance of the silicon-based negative active material, while maintaining the remaining preparation steps disclosed by CN ’544.
As to Claim 11:
CN ’544 does not disclose that the primary heat-treating of magnesium silicide is performed under an air atmosphere, as CN ’544 is silent with respect to the specific atmosphere (e.g., air, inert gas, or vacuum) used during the primary heat-treating step ([0015]–[0016]).
US ’475 discloses processing silicon-based negative active material precursors under oxidizing atmospheres, including air, during heat-treatment steps to promote controlled oxidation or formation of magnesium-containing silicon compounds in silicon-based negative electrode materials ([0021], [0026]). Thus, US ’475 teaches performing heat-treatment steps of silicon-based precursor materials under an air atmosphere, supplying the limitation not disclosed by CN ’544.
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to perform the primary heat-treating of magnesium silicide in CN ’544 under an air atmosphere, as taught by US ’475, as a routine process modification to control oxidation behavior and material properties during formation of porous silicon, while maintaining the remaining preparation steps disclosed by CN ’544.
As to Claim 12:
CN ’544 does not disclose that the primary heat-treating is performed at about 600°C to about 700°C for about 5 hours to about 30 hours, as CN ’544 does not specify the temperature range or duration for the primary heat-treating step ([0015]–[0016]).
US ’475 discloses heat-treating silicon-based precursor materials used for negative active materials at temperatures overlapping about 600°C to about 700°C and for durations extending for several hours to tens of hours, in order to promote controlled oxidation, phase formation, and improved material stability ([0021], [0026]). Thus, US ’475 teaches temperature and time conditions that overlap the claimed range of about 600°C to about 700°C for about 5 hours to about 30 hours, supplying the processing parameters not disclosed by CN ’544.
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to perform the primary heat-treating step of magnesium silicide in CN ’544 at about 600°C to about 700°C for about 5 hours to about 30 hours, as taught by US ’475, as a matter of routine optimization of heat-treatment conditions to control material formation and properties, while maintaining the remaining preparation steps disclosed by CN ’544.
As to Claim 13:
CN ’544 further discloses that the etching step is performed using an acid, as the heat-treated product is subjected to acid etching to remove magnesium-containing phases and thereby form porous silicon ([0017]–[0019]).
As to Claim 14:
CN ’544 further discloses that the etching step is performed by using an acid, as the heat-treated product is subjected to acid etching to remove magnesium-containing phases and thereby form porous silicon ([0017]–[0019]).
However, CN ’544 does not disclose that the acid used in the etching step is hydrochloric acid, as CN ’544 does not specify the particular acid species employed during the etching process.
US ’475 discloses silicon-based negative active materials and corresponding preparation methods that include chemical treatment of silicon-based precursors using mineral acids, and teaches that hydrochloric acid is a conventional and suitable acid for removing metal-containing phases and modifying silicon-based materials during processing ([0021], [0026]). Thus, US ’475 teaches the use of hydrochloric acid for an acid-treatment step corresponding to the limitation not disclosed by CN ’544.
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to perform the acid-etching step of the preparation method disclosed in CN ’544 using hydrochloric acid, as taught by US ’475, as a routine and predictable choice among known mineral acids for removing magnesium-containing phases, while maintaining the remaining preparation steps disclosed by CN ’544.
As to Claim 15:
CN ’544 does not disclose that the mixing ratio of the porous silicon and the amorphous carbon precursor is about 95:5 to about 55:45 by weight, as CN ’544 does not specify any quantitative weight ratio between the porous silicon and the carbon precursor used in the mixing step ([0020]–[0022]).
US ’475 discloses silicon-based negative active materials prepared using carbon precursors and expressly teaches that the amount of carbon (derived from an amorphous carbon precursor) may be selected within ranges that overlap about 5 wt% to about 45 wt% of the total negative active material to optimize conductivity and mechanical stability ([0022], [0024], [0031]). These disclosed carbon contents correspond to a porous silicon to carbon precursor weight ratio overlapping about 95:5 to about 55:45, thereby teaching the specific mixing-ratio limitation.
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to modify the preparation method of CN ’544 by selecting a mixing ratio of porous silicon to amorphous carbon precursor of about 95:5 to about 55:45 by weight, as taught by US ’475, as a matter of routine optimization to balance electrical conductivity and structural stability of the silicon-based negative active material, while maintaining the remaining preparation steps disclosed by CN ’544.
As to Claim 16:
CN ’544 does not disclose that the secondary heat-treating is performed at about 800°C to about 1200°C, as CN ’544 does not specify the temperature range for the secondary heat-treating step ([0022]–[0024]).
US ’475 discloses silicon-based negative active materials and corresponding preparation methods in which carbon coatings are formed by heat treatment at elevated temperatures, and expressly teaches performing carbonization or coating heat-treatment steps at temperatures overlapping about 800°C to about 1200°C to improve electrical conductivity and structural stability of silicon-based negative electrode materials ([0024], [0027], [0031]). Thus, US ’475 teaches the specific secondary heat-treating temperature range.
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to perform the secondary heat-treating step of the preparation method disclosed in CN ’544 at about 800°C to about 1200°C, as taught by US ’475, as a matter of routine optimization of carbonization conditions to obtain a stable carbon-coated porous silicon negative active material, while maintaining the remaining preparation steps disclosed by CN ’544.
As to Claim 17:
CN ’544 further discloses a rechargeable lithium battery comprising a negative electrode including a porous silicon/carbon composite negative active material, a positive electrode including a positive active material, and a non-aqueous electrolyte (Abstract; [0029]–[0031]). CN ’544 thus teaches a lithium-ion secondary battery having a negative electrode, a positive electrode with a positive active material, and a non-aqueous electrolyte.
As to Claim 18:
CN ’544 further discloses that the negative electrode includes a porous silicon/carbon composite as the negative active material ([0011], [0029]), thereby teaching a negative electrode including a silicon-based negative active material corresponding to the first negative active material.
However, CN ’544 does not disclose that the negative electrode further comprises crystalline carbon as a second negative active material, as CN ’544 does not expressly teach combining the silicon-based negative active material with a separate crystalline carbon (e.g., graphite) negative active material in the negative electrode.
US ’475 discloses silicon-based negative electrodes that include a silicon-based negative active material in combination with crystalline carbon, such as graphite, as a second negative active material, in order to improve conductivity, structural stability, and cycle life of lithium-ion batteries ([0032]–[0034]). Thus, US ’475 teaches the specific use of crystalline carbon as a second negative active material in a negative electrode containing a silicon-based first negative active material.
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to modify the rechargeable lithium battery of CN ’544 such that the negative electrode further comprises crystalline carbon as a second negative active material, as taught by US ’475, in order to improve conductivity and cycling stability of the silicon-based negative electrode, while maintaining the overall battery structure disclosed by CN ’544.
As to Claim 19:
CN ’544 further discloses that the negative electrode includes a silicon-based negative active material (porous silicon with a carbon layer) ([0011], [0029]). Thus, CN ’544 teaches a rechargeable lithium battery having a negative electrode comprising a first negative active material corresponding to a silicon-based active material.
However, CN ’544 does not disclose that the negative electrode further comprises crystalline carbon as a second negative active material in a specific mixing ratio relative to the first negative active material, nor does CN ’544 disclose a mixing ratio of about 1:99 to about 40:60 by weight between a silicon-based active material and crystalline carbon ([0030]).
US ’475 discloses negative electrodes for rechargeable lithium batteries in which a silicon-based negative active material is combined with crystalline carbon (e.g., graphite) as a second negative active material, and further teaches that the silicon-based active material may be present in minor to moderate amounts relative to the crystalline carbon, with disclosed ranges overlapping about 1 wt% to about 40 wt% silicon-based active material and about 60 wt% to about 99 wt% crystalline carbon ([0032]–[0036]). These disclosed ranges correspond to the claimed mixing ratio of about 1:99 to about 40:60 by weight between the first and second negative active materials.
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to modify the rechargeable lithium battery of CN ’544 such that the negative electrode comprises a mixture of a first silicon-based negative active material and a second crystalline carbon negative active material at a mixing ratio of about 1:99 to about 40:60 by weight, as taught by US ’475, as a matter of routine optimization to improve electrochemical performance and cycle life, while maintaining the overall battery structure disclosed by CN ’544.
As to Claim 20:
CN ’544 discloses a negative active material for a rechargeable lithium battery comprising a porous silicon core and a carbon layer formed on the surface of the porous silicon by mixing porous silicon with a carbon precursor followed by secondary heat treatment (Abstract; [0011], [0020]–[0024]). CN ’544 thus teaches a negative active material having a porous silicon core and a carbon layer, corresponding to the negative active material recited in claim 1, from which claim 20 depends.
However, CN ’544 does not disclose that magnesium is comprised in the negative active material as a MgSiO₃ compound, nor does CN ’544 disclose that the carbon layer is included in an amount of about 5 wt% to about 45 wt% based on the total amount of the negative active material, as CN ’544 does not specify retention of magnesium compounds after etching or a quantitative amount of the carbon layer ([0017]–[0019], [0022]–[0024]).
US ’475 discloses silicon-based negative active materials that include magnesium silicate compounds, such as MgSiO₃, incorporated in silicon-based active materials to improve structural stability and electrochemical performance ([0027]–[0030]). US ’475 further teaches that the amount of carbon in silicon-based negative active materials may be selected within ranges overlapping about 5 wt% to about 45 wt%, thereby teaching the claimed carbon-layer amount ([0022], [0024], [0031]).
It would have been obvious to a person skilled in the art before the effective filing date of the instant application to modify the negative active material of CN ’544 to include magnesium in the form of a MgSiO₃ compound and to select a carbon layer amount of about 5 wt% to about 45%, as taught by US ’475, as a matter of routine compositional optimization to improve stability and electrochemical performance of the silicon-based negative active material, while maintaining the porous silicon/carbon structure disclosed by CN ’544.
Response to Arguments
Applicant’s arguments with respect to claims 1-7 and 10-20 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JIMMY K VO whose telephone number is (571)272-3242. The examiner can normally be reached Monday - Friday, 8 am to 6 pm EST.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Tiffany Legette can be reached at (571) 270-7078. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/JIMMY VO/
Primary Examiner
Art Unit 1723
/JIMMY VO/Primary Examiner, Art Unit 1723