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 .
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 12/23/2025 has been entered.
Response to Amendment
This is a non-final Office action in response to Applicant’s remarks and amendments filed on 12/23/2025. Claim 1 is amended. Claims 1 – 7 and 10 – 13 are pending in the current Office action.
The 35 U.S.C. 103 rejection set forth in the previous Office action is withdrawn. A new grounds of rejection, utilizing Sugimori’s taught silicon-containing material content range, is established below.
Response to Arguments
Applicant's arguments filed 12/23/2025 have been fully considered but they are not persuasive. Specifically, applicant argues that, per Table 4, the instant invention shows the most excellent capacity retention results with the SiO content in the second negative electrode active material layer is between 9 and 12 wt% (Refer to Examples 8 – 9).
Examiner acknowledges that, per Table 4, Examples 8 and 9, which have a content of SiO 12 wt% and 9 wt%, respectively, show a high capacity retention rate; however, the Examiner respectfully notes that that the such a content of SiO only appears critical when the negative electrode active material further includes artificial graphite, the SiO content in the lower active material layer is 0 wt% and 3 wt% respectively {i.e. narrower than claimed range of W2 > 2*W1}, the upper active material layer has a specific surface area (B2) of 1.65 m2/g, the lower active material layer has a specific surface area (B1) of 18 m2/g, and the ratio of the specific surface area of the first (B2-1) and second active materials (B2-2) included in the upper layer (B2-2/B2-1) is 0.72 (Refer to Table 4), and as claim 1 allows for any selection of first and second negative electrode active material, a broader ratio of SiO content in the first and second layer, and any selection of specific surface area for the first active material, second active material, upper {i.e. second} active material layer, and lower {i.e. first} active material layer, it is unclear that the instant W2 range would be critical across such a broad selection of active material, surface areas, and/or SiO content ratios. Accordingly, the examiner respectfully submits that applicant’s showing of criticality/unexpected results corresponds to a scope that is narrower than the scope of the claimed invention, and, as MPEP 716.02(d) requires unexpected results to be commensurate with the claimed scope, applicant’s argument of unexpected results is unpersuasive.
The examiner further notes based on Example 1, that the inclusion of SiO is not seemingly necessary to obtain a comparable capacity retention rate {i.e. without SiO achieves capacity retention of 93% which is higher than Examples 8 and 9}, and that based at least the results shown in Tables 1 – 2, that the specific surface areas of the first and second active material layers and the specific surface area of the first and second active materials included in the second active material layer also appear to have an effect on the capacity retention. Therefore, based on the working examples of the instant specification, there appears to be other factors that are at least partially responsible for the unexpected results {i.e. superior capacity results}, and there are no limitations addressing these factors {i.e. such as the specific surface area ratio of the layers or active materials} in the independent claim which further renders the claimed invention incommensurate in scope with applicant’s showing of unexpected/ superior results.
In response to applicant's argument that, in Sugimori, increasing the SiO content in the surface layer from 5 wt% to 7.5 wt% does not increase the direct-current internal resistance (DCIR), the fact that the inventor has recognized another advantage which would flow naturally from following the suggestion of the prior art cannot be the basis for patentability when the differences would otherwise be obvious. See Ex parte Obiaya, 227 USPQ 58, 60 (Bd. Pat. App. & Inter. 1985).
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.
Claim(s) 1 – 7, 10 – 11 and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Sugimori (US PG Pub. 2016/0351892 A1) in view of Chung (WO2019088672A1, US PG Pub. 2020/0185719 A1 used as English translation), Soma (JP2017062911A), and Thomas-Aleya (US PG Pub. 2012/0328942 A1). {Examiner Note: All prior art was cited in previous Office action mailed 09/04/2025}.
Regarding Claim 1, Sugimori discloses a negative electrode for a secondary battery (Fig. 1 and 3, 14; [0015 – 0016];[0021]), comprising: a current collector (Fig. 1, 14a; [0021]); a first negative electrode active material layer formed on the current collector and containing a first active material (Fig. 1, 14b; [0021 – 0022]); and a second negative electrode active material layer formed on the first negative electrode active material containing a second active material (Fig. 1, 14c; [0021 – 0022]), wherein the first and second negative electrode active material layers further include a silicon oxide-based active material represented by the formula SiOx, wherein 0 < x < 2 ([0028];[0030]).
Sugimori teaches including a larger amount of silicon-containing material placed in the surface-side region rather than the current collector-side region. In working examples 5 – 6, Sugimori discloses including a content of silicon oxide-based active material in the second active material layer {i.e. surface-side sub layer 14c} that is three times greater than the content of silicon oxide-based active material in the first active material layer {i.e. collector-side sub layer 14b} (Table 1; [0068 – 0069];0071 – 0071]); therefore, Sugimori further discloses an electrode embodiment wherein the silicon oxide-based active materials in the first and second negative electrode active material layers is expressed by W2 = 3W1, which satisfies the Relational Equation 1: W2 > 2*W1, where W1 is a content of the silicon oxide-based active material in the first negative electrode active material layer and W2 is a content of the silicon oxide-based active material in the second negative electrode active material layer. Furthermore, in the embodiment of example 5 – 6, W1 is 2.5 wt%, which satisfies the claimed range of W1 > 0.
However, in examples 5 – 6, W2 is 7.5 wt% (Refer to Examples 5 – 6 in Table 1); therefore, Sugimori does not explicitly disclose wherein the silicon-based active material in the second negative electrode active material layer satisfies 9 ≤ W2 ≤ 12 wt%.
Generally Sugimori teaches having a larger amount of silicon-containing material in the surface side region of the electrode {i.e. sub-layer 14c} than the current-collector side region of the electrode {i.e. sub-layer 14b} ([0033]). Sugimori further teaches having, in each negative electrode active material layer, the content of silicon-containing most preferably 1 to 20% by mass with respect to the total amount of negative electrode active material ([0032]). Sugimori further teaches that increasing the amount of silicon-containing material increases the influence of the expansion and contraction of the silicon-containing material and that decreases in the amount of silicon-containing active material decrease the increase capacity effect of the material ([0032]).
It would have been obvious to one with ordinary skill in the art, before the effective filing date of the claimed invention, to modify the content of the silicon-oxide based material in the second negative electrode active material of Sugimori’s example to be within the overlapping portion of Sugimori’s taught range and the claimed range, and thus obtain a negative electrode with active material layers having silicon-oxide bases oxide contents that satisfy the claimed relationship of 9 ≤ W2 ≤ 12 wt% to optimize the capacity of the battery while also minimizing the influence of the expansion and contraction of the silicon-containing material and achieving a higher content of silicon-containing active material in the surface side region of the electrode, with a reasonable expectation of success and without undue experimentation [MPEP 2144.05(II)]. Furthermore, by having a W2 within the claimed range, modified Sugimori, as established above, would still satisfy W2 > 2*W1.
The active material layers of Examples 5 – 6 further include graphite powder as the primary active material ([0068 – 0069];[0071 – 0072]).
Sugimori does not disclose the specific surface area of the active material in the embodiments, and therefore modifies Sugimori does not explicitly disclose the second active material being a bimodal active material comprising active materials having different specific surface area.
Soma teaches a negative electrode active material including a first negative electrode active material layer on the collector and a second active material layer on the first negative electrode active material layer ([0014 – 0016]). The active material of both layers is taught by Soma to include primarily graphite, with the second active material further including low-crystalline carbon active material ([0018 – 0019]). Soma’s electrode configuration is taught to provide an electrode with high capacity and improved high-rate charge acceptance as well as cycle life performance ([0014]). The upper layer, by including the low-crystalline carbon, specifically improves the efficiency of the insertion and release of lithium ions that allows for high-rate discharge ([0018]). Soma additionally teaches that the electrode layers can further include silicon oxide active material ([0024]).
Chung teaches a negative electrode active material containing a first and second graphite material which are each at least one selected from natural graphite, artificial graphite, kish graphite, graphitized carbon fibers, graphitized mesocarbon microbeads and amorphous carbon that have different specific surface areas ([0039];[0056];[[0059]). The first particles, which are present in an amount of 50 – 99 wt% based on 100% of the negative electrode active material and have a specific surface area ranging 0.01 – 1.0 m2/g ([0017 – 0018]). The second particles are taught to have a specific surface area ranging from 0.05 – 2.6 m2/g ([0020]). Chung further teaches that, when the active materials have a specific surface area outside of the taught range, an increase in side reaction with the electrolyte occurs ([0057]). Overall, Chung’s active material is taught to provide a negative electrode with improved high-rate and quick charging characteristics ([0024]).
Since Sugimori teaches using graphite as the primary active material of their double-layer electrode embodiments ([0068 – 0069];[0071 – 0072]), and Soma teaches that, in a graphite-based double layer negative electrode it is beneficial to further include an additional, lower-crystalline carbon in the second active material layer ([0018]), it would have been obvious to one with ordinary skill in the art, before the effective filing date of the claimed invention, to use Chung’s taught active material as the graphite active material of Sugimori’s second active material layer, and thus obtain the claimed bimodal second active material layer, with a reasonable expectation of success that in obtaining a negative electrode with the benefits of improved high rate discharge and quick charging characteristics.
Modified Sugimori does not explicitly disclose a specific surface area (B2) of the second active material being larger than a specific surface area (B1) of the first active material.
Thomas-Aleya teaches forming, in negative electrodes with multiple active material layers, a particle specific surface area gradient where the surface area change, stepwise, with each layer ([0096];[0104];[0106]). Particularly Thomas-Aleya teaches having the back layer of the electrode {i.e. layer on the collector/first active material layer} include particles with a lower specific surface area and the front layer of the electrode {i.e. upper layer nearest to separator} include particles with a higher specific surface area ([0104 – 0106];[0108]). The change in specific surface area provides low resistances and high rate characteristics while minimizing side reactions and capacity losses ([0110 – 0111]). Thomas-Aleya further teaches that the active materials of such negative electrodes can include graphitic material ([0145]).
It would have been obvious to one with ordinary skill in the art, before the effective filing date of the claimed invention, to control the specific surface areas of Sugimori’s first and second active material layers to have a stepwise specific surface area change, where the first layer {i.e. lower layer} has a smaller particle specific surface area than the second layer {i.e. upper layer}, as taught by Thomas-Aleya, and thus form the claimed active material layers, with a reasonable expectation of success in achieving a negative electrode with the benefits of minimized side reactions and capacity loss as well as low resistance and high rate characteristics.
As established above, modified Sugimoto’s second active material layer includes two different carbon active materials and the materials have different specific surface areas. The first material, the main graphite material, has a specific surface area larger than the second material. One with ordinary skill in the art would recognize that, because modified Sugimori’s second active material layer contains two materials with different specific surface areas, the specific surface area (B2) of the second active material of modified Sugimori is necessarily an average specific surface area of the active material (2-1-th active material) having a large specific surface area and the active material (2-2-th active material) having a small specific surface area. One with ordinary skill in the art would further recognize that by being an active material mixture, modified Sugimori’s second active material is, like the claimed second active material, a homogeneous mixture including the 2-1-th active material and 2-2-th active material.
In addition, since modified Sugimori provides the claimed structure necessary to obtain the specific surface area in the manner claimed by the applicant {i.e. a mixed active material layer with two active materials having different specific surface areas}, the specific surface area of modified Sugimori’s second active material layer necessarily has the capability of being obtained by adjusting the specific surface area of the 2-1-th active material, the specific surface area of the 2-2-th active material, and a mixing weight ratio between the 2-1-th active material and the 2-2-th active material.
{Examiner Note: The applicant’s recitation: -- and the specific surface area (B2) of the second active material is obtained by adjusting the specific surface area of the 2-1-th active material, the specific surface area of the 2-2-th active material, and a mixing weight ratio between the 2-1-th active material and the 2-2-th active material – is a product-by-process claim limitation that is not limited to the manipulations of the recited steps, only the structure implied by the steps}.
Regarding Claims 2 – 3, modified Sugimori discloses all limitations as set forth above. As established above, modified Sugimori’s second active material layer includes two active materials with different specific surface areas. The 2-1-th active material particles have a specific surface area ranging from 0.05 – 2.6 m2/g and the 2-2-th particles have a specific surface area ranging from 0.01 – 1.9 m2/g (Chung: [0056]). Based on the taught ranges, one with ordinary skill in the art would recognize that modified Sugimori’s second active material would necessarily provide a specific surface area ratio {i.e. specific surface area of 2-2-th active material: 2-1-th active material} that overlaps/encompasses the claimed ranges of 30 to 90% (Claim 2) and 40 to 90% (Claim 3).
Chung teaches that when active materials have a specific surface area outside of the taught ranges an increase in side reactions with the electrolyte occurs ([0057]). Overall, Chung’s active material is taught to provide a negative electrode with improved high-rate and quick charging characteristics ([0024]).
Thomas-Aleya teaches that higher specific surface area particles have lower volumetric charge transfer resistance and/or better charge transfer resistance per unit of specific surface area while lower specific surface area particles provide higher specific charge transfer resistance ([0110]). Thomas-Aleya further teaches that, while it is desirable to increase the overall specific surface area of an electrode active material to achieve low-resistance and high-rate characteristics, increases in particle specific surface areas can also lead to increased side reactions that cause losses in capacity and reduced battery safety ([0111]).
Selection of specific surface areas for 2-1-th and 2-2-th active material that provide a ratio within the claimed range would have been obvious to one with ordinary skill in the art to optimize the effects {i.e. low resistance and high rate characteristics vs. increases in side reactions} caused by the larger specific surface area and smaller specific surface area particles within the active material, with a reasonable expectation of success and without undue experimentation [MPEP 2144.05(II)].
Regarding Claims 4 – 5, modified Sugimori discloses all limitations as set forth above. As established above, modified Sugimori’s first active material layer has a specific surface area smaller than the second active material layer. The first active material has a specific surface area ranging from 0.02 – 4 m2/g ([Thomas-Aleya: [0108]). The second active material would have an average specific surface area, based on the taught composition and specific surface area ranges, of ≈ 0.042 – 2.76 m2/g (Chung: [0055 – 0056]). With such specific surface area ranges for the first and second active materials, one with ordinary skill in the art would recognize that modified Sugimori would necessarily provide a specific surface area ratio {i.e. specific surface area of the first active material : second active material material} that overlaps/encompasses the claimed ranges 20 – 95% (Claim 4) and 40 – 95% (Claim 5).
Thomas-Aleya teaches that higher specific surface area particles have lower volumetric charge transfer resistance and/or better charge transfer resistance per unit of specific surface area while lower specific surface area particles result in higher specific charge transfer resistance ([0110]). Thomas-Aleya further teaches that, while it is desirable to increase the overall specific surface area of an electrode active material to achieve low-resistance and high-rate characteristics, increases in particles specific surface areas can also lead to increased side reactions that cause losses in capacity and reduced battery safety ([0111]).
Selection of specific surface areas for the first and second active materials that provide a ratio within the claimed range would have been obvious to one with ordinary skill in the art, before the effective filing date of the claimed invention, to optimize the effects {i.e. low resistance and high rate characteristics vs. increases in side reactions} caused by the larger specific surface area material layer and smaller specific surface area material layer, with a reasonable expectation of success and without undue experimentation [MPEP 2144.05(II)].
Regarding Claims 6 – 7, modified Sugimori discloses all limitations as set forth above. Sugimori teaches using graphite as the main active material of the first and second active material layers ([0068 – 0069];[0071 – 0072]). Sugimori generally teaches using, as the graphite, natural graphite, non-graphitizable carbon, and artificial graphite ([0032]).
Modified Sugimori does not particularly disclose in the embodiments wherein the first and second active materials are artificial graphite (Claims 6 and 7).
Thomas-Aleya teaches that a graphitized natural or synthetic material can serve as negative active materials ([0145]). Synthetic graphite is further taught by Thomas-Aleya to be suitable for active material layers that are included on {i.e. first active material layer} and away from the collector {i.e. second active material layer} ([0024 – 0025]).
Since Sugimori already teaches from a finite list of graphite materials using artificial graphite, it would have been obvious to one with ordinary skill in the art to specifically have the active material be artificial graphite, with a reasonable expectation of success that such a selection would be a suitable graphite active material for the negative electrode embodiments in Sugimori.
Regarding Claims 10 – 11, modified Sugimori discloses all limitations as set forth above. Sugimori further discloses wherein the first and second active material layers further comprise a binder, and the binder is a water soluble binder (Claim 10) and further wherein the binder comprises styrene-butadiene rubber, that is, in both active material layers in the example embodiments, Sugimori discloses the binder for the active material including styrene-butadiene rubber ([0068 – 0069];[0071 – 0072]), which is a water soluble binder material exemplified by the applicant (Instant Specification: [0040]).
Regarding Claim 13, modified Sugimori discloses all limitations as set forth above. Sugimori further discloses a secondary battery comprising: a positive electrode (Fig. 3, 13; [0044];[0061]); a separator interposed between the negative electrode and the positive electrode (Fig. 3, 15; [0049];[0061]); and an electrolyte ([0046 – 0048];[0061]).
Claim(s) 12 is rejected under 35 U.S.C. 103 as being unpatentable over Sugimori (US PG Pub. 2016/0351892 A1) in view of Chung (WO2019088672A1, US PG Pub. 2020/0185719 A1 used as English translation), Soma (JP2017062911A) and Thomas-Aleya (US PG Pub. 2012/0328942 A1), as applied to claim 1 above, and further in view of Lee (US PG. Pub. 2019/007740 A1 – cited in previous Office action mailed 09/04/2025). {Examiner Note: For the rejection of claim 12, the examiner has interpreted “wherein the negative electrode has a rolling density of 1.65 to 1.85 g/cc” to mean that the average rolling density of the negative electrode ranges from 1.65 to 1.85 g/cc.}
Regarding Claim 12, modified Sugimori discloses all limitations as set forth above. Sugimori teaches performing rolling, after applying and drying the active material layers, to manufacture their negative electrode and obtain a desired thickness ([0054 – 0056]).
Modified Sugimori does not disclose the rolling density of the negative electrode being 1.65 to 1.85 g/cc.
Lee teaches a multilayered negative electrode including a first negative electrode active material layer {i.e. layer on the collector} and a second negative electrode active material layer {i.e. layer on top of the first layer} ([0013 – 0014]). The negative electrode active materials utilized by Lee include carbon-based materials such as graphite ([0042]). Lee further teaches applying the active material layers with densities that provide an average electrode density of 1.2 g/cc or more ([0016];[0018]). When the average electrode density falls below 1.2 g/cc, Lee teaches that the adhesion, capacity maintenance rate, and output characteristics of the electrode decreases ([0019]). An average electrode density excessively above 1.2 g/cc {i.e. The highest average density Lee teaches is 1.85 g/cc, which is based on the additional ranges they include for the first and second active material layers in [0014]} indicates that one or both layers of active material have a density that is excessively high. Lee teaches the when the densities of the layers are too high the particle strength of the layers are too low and result in an overall reduction in electrolyte impregnability and ion diffusion for the electrode ([0017]). {Examiner Note: The densities taught by Lee are the densities after the active material layers are dried and rolled (Refer the preparation method disclosed in Lee’s example in [0083]; therefore, the examiner is interpreting the density taught by Lee to be the same as the claimed “rolling density”.}
It would have been obvious to one with ordinary skill in the art, before the effective filing date of the claimed invention, to have controlled modified Sugimori’s active material layers to have, after rolling, densities that provide an average rolling density of 1.22 g/cc or more, as taught by Lee, with a reasonable expectation of success in obtaining active material layers with high adhesion and increased output characteristics.
Selection of rolling densities that provide an average rolling density within the claimed range would have been obvious to one with ordinary skill in the art, before the effective filing date of the claimed invention, to achieve optimal adhesion, particle strength, and output characteristics for the electrode without reducing the electrolyte impregnability and ion diffusion capability of the electrode, with a reasonable expectation of success and without undue experimentation [MPEP 2144.05(II)].
Conclusion
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/A.Y.O./Examiner, Art Unit 1751
/JONATHAN G LEONG/Supervisory Patent Examiner, Art Unit 1751 3/3/2026