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 II, a silicon anode in the reply filed on 08/20/2025 is acknowledged.
Claims 1-9 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected Group I, a silicon material, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 08/20/2025.
Information Disclosure Statement
The information disclosure statement filed 08/05/2024 fails to comply with the provisions of 37 CFR 1.97, 1.98 and MPEP § 609 because a signature and date is missing on page 4. It has been placed in the application file, but the information referred to therein has not been considered as to the merits. Applicant is advised that the date of any re-submission of any item of information contained in this information disclosure statement or the submission of any missing element(s) will be the date of submission for purposes of determining compliance with the requirements based on the time of filing the statement, including all certification requirements for statements under 37 CFR 1.97(e). See MPEP § 609.05(a).
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 10, 13 are rejected under 35 U.S.C. 103 as being unpatentable over Bogart et al. US20200099043A1.
Regarding claim 10, Bogart discloses a silicon anode (abstract) comprising:
a plurality of silicon particles (“silicon nanoparticles”);
a coating (“conductive pyrolytic carbon matrix”) in which the plurality of silicon particles are dispersed ([0016], [0101]), thereby surrounding each silicon particle of the plurality of silicon particles,
wherein the coating maintains a connection with the silicon nanoparticles during volumetric expansion during charging and discharging ([0101]) and thus accommodates a volumetric expansion of the plurality of silicon particles during lithiation or delithiation.
Bogart does not explicitly indicate a thickness of the coating as being between 1 and 100 nm; however, Bogart indicates that a ratio of carbon to silicon in the coated particles, i.e., a ratio of the carbon-based coating weight to silicon particle weight, is preferably within a range of 0.3 to 0.45 ([0077]), and further discloses a diameter of the silicon particles is at least 30 nm to prevent an excessive surface area from interfering with bonding the silicon particles to the coating and decreasing the silicon lithiation capacity ([0126]), while less than 500 nm to prevent difficulties in packing silicon particles and requiring an excessive amount of coating ([0126]). Increasing the size of a coated particle while maintaining a ratio of carbon-based coating to silicon increases a corresponding thickness of the coating ([0126]); as such, in seeking to balance limiting surface area in the silicon particles to prevent coating interference while also maintaining the packing ability of the particles to avoid excessive amounts of coating as disclosed by Bogart, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to optimize a silicon particle diameter between 30-500 nm (MPEP 2144.05 II), and in doing so, one would also optimize a coating thickness.
While Bogart does not explicitly indicate a thickness of the coating, given that a weight of the coating is slightly less than half that of the silicon particles ([0077]) and the particles have a diameter of 30-500 nm ([0126]), one having ordinary skill in the art would reasonably utilize at least a portion of the claimed range of thickness between 1 to 100 nm on a similar scale to the 30-500 nm particles.
Bogart further discloses the silicon anode comprises a coating configured to promote a stable SEI layer ([0068]), and comprises a conductive additive in electrical contact with the plurality of silicon particles ([0157]).
Regarding claim 13, modified Bogart discloses the silicon anode of Claim 10, wherein the coating is further configured to hinder oxidation or corrosion of the plurality of silicon particles ([0023]).
Claims 11 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Bogart (US20200099043A1) as applied to claim 10, further as evidenced by or in view of NPL Huang et al. “Evolution of the Solid−Electrolyte Interphase on Carbonaceous Anodes Visualized by Atomic-Resolution Cryogenic Electron Microscopy” (copy provided; see IDS)
Regarding claims 11 and 12, modified Bogart discloses the silicon anode of Claim 10. Bogart discloses the silicon anode has a coating configured to form a stable SEI layer on a carbon surface ([0068]), including a reduced BET surface area to minimize SEI formation during the first charge charge-discharge cycle ([0136]), but does not explicitly indicate a thickness of the SEI layer as being at most 150 nm thick.
Huang, directed to SEI formation on a carbon surface being a carbonaceous negative electrode (Huang, abstract), notes that competing reactions during the first cycle cause the formation of either a desirable compact SEI layer or an undesirable extended SEI layer (Huang pp. 5145 col. 2 paragraph 4, FIG. 5). Huang further teaches that selecting or modifying electrode surfaces to favor compact SEI reactions improves battery lifetime (pp. 5146 col. 1 paragraph 1), noting that early growth of the extended SEI expands quickly even after only the first cycle (pp. 5143 col. 1 paragraph 1, pp. 5146 col. 1 paragraph 1).
Bogart, which discloses surface selection and modification to stabilize SEI formation (Bogart [0068]) and to minimize SEI growth during the first cycle ([0136]), evidenced by Huang as resulting in formation of a compact SEI (Huang pp. 5145 col. 2 paragraph 4, pp. 5146 col. 1 paragraph 1), thus inherently discloses (claim 12) a silicon anode wherein the SEI layer is compact; Huang further discloses that the compact SEI layer has a thickness of 5 nm (pp. 5144 col. 1 paragraph 3-col. 2 paragraph 1) which falls within the claimed maximum of (claim 11) 150 nm or less.
Assuming arguendo that Applicant proves that Bogart’s silicon anode does not necessarily or inherently form a SEI layer having a thickness of 150nm or less or of forming a compact SEI layer, in seeking to improve the lifetime of Bogart’s battery it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to modify a surface of Bogart’s silicon anode in order to form a compact SEI having a thickness of 5 nm as taught by Huang; such a modification would be made with a reasonable expectation of success as Bogart envisions the selection and modification of the silicon anode surface to stabilize SEI formation (Bogart [0068]).
Claim 15 is rejected under 35 U.S.C. 103 as being unpatentable over Bogart (US20200099043A1) as applied to claim 10, further as evidenced by Fukuoka et al. JP6394498B2 (see attached machine translation)
Regarding claim 15, modified Bogart discloses the silicon anode of Claim 10. Bogart further discloses an experimental example wherein the silicon anode has a carbon coating layer grown using CVD of ethylene gas at 900 °C ([0199]), but does not explicitly indicate that this coating layer comprises graphite.
Fukuoka, directed to formation of a graphite coating using a CVD treatment (Fukuoka [0008]), discloses that the reaction to form a graphite coating through CVD takes place at a temperature of 700 to 1200 °C ([0020-0021]) using hydrocarbons such as ethylene ([0022]).
As such, Bogart’s experimental example involving CVD of ethylene gas at 900 °C would inherently form a coating comprising graphite grown using a CVD process; see MPEP 2112 III.
Bogart further discloses the use of carbon black as the conductive additive (Bogart [0070]).
Claims 16-18 are rejected under 35 U.S.C. 103 as being unpatentable over Bogart (US20200099043A1) as applied to claim 10, further as evidenced by NPL Quiang et al. “Mechanochemical Synthesis of Advanced Materials for All-Solid-State Battery (ASSB) Applications: A Review” (copy provided; see IDS).
Regarding claim 16, modified Bogart discloses the silicon anode of Claim 10. While Bogart does not explicitly disclose a silicon content of the silicon particles, Bogart discloses the silicon particle starting material preferably comprises at least 99% silicon by weight ([0045]). Furthermore, in manufacturing the silicon anode, Bogart takes precautions to avoid contact of the silicon nanoparticles with oxygen or water to prevent formation of an oxide layer on the silicon particles ([0059-0062]); while the finished silicon anode contains some oxygen or nitrogen, the oxygen or nitrogen is disposed at an interface as a bridging atom between the silicon particle surface and the coating ([0023], [0038]) instead of in the form of oxidation of the silicon particles.
Thus, Bogart’s silicon anode comprising precursor silicon particles initially having at least 99% silicon by mass prevented from oxidation during processing would maintain at least 99% silicon by mass in the finished product (MPEP 2112 III).
While Bogart does not explicitly disclose the silicon particle as being nonporous, Bogart does not disclose the use of a porous silicon particle starting material ([0045-0049]) or any apparent processes such as chemical etching that would add a porosity to the silicon particles ([0052-0068]); Bogart further indicates a desirability of minimizing a porosity of the composite particles containing the plurality of silicon particles and coatings ([0130-0131]); as such, Bogart’s silicon particles are understood to be nonporous.
While Bogart does not explicitly disclose the silicon particle as being spheroidal, Bogart utilizes a wet ball milling process of the silicon starting material to produce the plurality of silicon particles ([0052], [0176]). As evidenced by Quiang, the use of wet ball milling to reduce the size of silicon particles generates rounded particles (Quiang pp. 20 paragraph 4-pp. 21 paragraph 1), Bogart’s rounded silicon particles produced through wet ball milling being broadly and reasonably interpreted as spheroidal silicon particles.
Regarding claims 17 and 18, modified Bogart discloses the silicon anode of Claim 16, wherein the silicon particle comprises a characteristic size, understood as a radius (Instant specification, [0029]) of a secondary structure formed by a plurality of particles ([0029], FIG. 2A) such as Bogart’s composite particle formed from a plurality of the coated silicon particles (Bogart [0022]).
Bogart further provides an experimental example of a composite particle comprising an average diameter D50 of 6 µm (pp. 14, Table 3 Example 5, [0176-0181], [0121]), the diameter of 6 µm equivalent to a characteristic size (a radius) of 3 µm within the claimed ranges of (claim 17) 0.3-10 µm and (claim 18) 3 µm ± 500nm.
Claims 14 and 19-20 are rejected under 35 U.S.C. 103 as being unpatentable over Bogart (US20200099043A1) as applied to claim 10, further in view of Lee et al. US20180006294A1.
Regarding claim 14, modified Bogart discloses the silicon anode of Claim 10. Bogart further discloses that the coating is able to maintain a robust connection between the silicon particles throughout expansion and contraction during charging and discharging ([0101]), which would necessitate some degree of elasticity in the coating in order to repeatedly follow the expansion without breaking.
Assuming arguendo that Applicant proves modified Bogart’s coating is not elastic, it would be obvious to provide an elastic polymer layer on the surface of modified Bogart’s coating which would provide the coating with elasticity as taught by Lee; see below.
Lee, directed to permeable polymer-based membranes for silicon particles (Lee [0013-0014]), teaches the use of a coating of flexible polymer able to expand and contract with minimal mechanical failure, i.e., elasticity, ([0096]) which may be applied to a silicon anode comprising composites of silicon particles with a carbon coating ([0108]). Advantageously, a SEI formed on the polymer coating having improved mechanical resilience is less likely to break and reform during cycling ([0092]); the cyclized polyacrylonitrile polymer coating further provides conductivity ([0096] [0111]) and improves the cycling performance and allows for increased mass loading of silicon material ([0109]).
As such, in seeking to form the SEI on a mechanically resilient surface to prevent breakage and reformation of the SEI during cycling and improve the conductivity of a surface of modified Bogart’s silicon anode, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to modify Bogart’s carbonaceous coating to also include a coating of elastic polymer as taught by Lee. Such a modification would be made with a reasonable expectation of success as Bogart envisions providing the carbonaceous coating surrounding the coated silicon particles to improve these properties and because Lee teaches a suitability of providing the elastic polymer coating on a silicon and carbon composite such as the composite disclosed by modified Bogart; see MPEP 2144.07. One having ordinary skill in the art would further have appreciated the benefits of the polymer in improving the cycling performance and mass loading of silicon material as taught by Lee.
Regarding claims 19-20, modified Bogart discloses the silicon anode of claim 10. While Bogart recognizes the problem of an inability of a SEI formed on a surface of a silicon particle to accommodate the expansion and contraction of the silicon leading to ([0005]), and envisions the use of an additional layer in the coating to provide a surface for SEI formation and improve the surface conductivity ([0068]), Bogart does not explicitly disclose the use of a coating comprising a polymer comprising at least one of the polymers recited in claim 19 or a cyclized polymer for this purpose.
Lee, directed to permeable polymer-based membranes for silicon particles (Lee [0013-0014]), teaches the use of a cyclized polyacrylonitrile polymer coating ([0096]) which may be applied to a silicon anode comprising composites of silicon particles with a carbon coating ([0108]). Advantageously, a SEI formed on the polymer coating having improved mechanical resilience is less likely to break and reform during cycling ([0092]); the cyclized polyacrylonitrile polymer coating further provides conductivity ([0096] [0111]) and improves the cycling performance and allows for increased mass loading of silicon material ([0109]).
As such, in seeking to form the SEI on a mechanically resilient surface to prevent breakage and reformation of the SEI during cycling and improve the conductivity of a surface of modified Bogart’s silicon anode, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to modify Bogart’s carbonaceous coating to include a coating of cyclized polyacrylonitrile as taught by Lee. Such a modification would be made with a reasonable expectation of success as Bogart envisions providing the carbonaceous coating surrounding the coated silicon particles to improve these properties and because Lee teaches a suitability of providing the cyclized polyacrylonitrile polymer coating on a silicon and carbon composite such as the composite disclosed by modified Bogart; see MPEP 2144.07. One having ordinary skill in the art would further have appreciated the benefits of the polymer in improving the cycling performance and mass loading of silicon material as taught by Lee.
Conclusion
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/E.C./Examiner, Art Unit 1751
/JONATHAN G LEONG/Supervisory Patent Examiner, Art Unit 1751 9/29/2025