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 .
Status of Claims
Applicant’s amendment and arguments, filed 07/28/25, have been fully considered. Claim(s) 1, 11, and 22 is/are amended; claim(s) 2–8, 10, and 12–18 stand(s) as originally or previously presented; claim(s) 9 and 19–21 is/are canceled; and claim 23 is added without entering new matter. Examiner affirms that the original disclosure provides adequate support for the amendment.
Upon considering said amendment and arguments, the previous 35 U.S.C. 103 rejection set forth in the Office Action mailed 04/29/2025 has/have been withdrawn. Applicant’s amendment necessitated the new grounds of rejection below.
Claim Objections
It is recommended that Applicant amend claim 11 as follows: in line 12, “the silicon oxide … includes a lithium silicate” should seemingly read “the silicon oxide … includes [[a]] the lithium silicate” to denote proper antecedence from claim 1’s recitation of the lithium silicate. Appropriate correction is required.
Claim Rejections - 35 USC § 103
The text forming the basis for the rejection under 35 U.S.C. 103 may be found in a prior Office Action.
Claim(s) 1, 2, 5–8, 10, 16–18, and 22 is/are rejected under 35 U.S.C. 103 as being unpatentable over Yang et al. (US 20160079591 A1) (Yang) in view of Park et al. (KR 20140085822 A) (Park), Hirose et al. (US 20190229332 A1) (Hirose), and Kang et al. (US 20140205907 A1, from 04/29/25 PTO-892) (Kang).
Regarding claims 1, 2, 6, 16, 17, and 22, Yang discloses a lithium secondary battery (e.g., ¶ 0001) comprising a negative electrode active material (Abstract) comprising a core (interior of coating, FIG. 1) comprising a silicon oxide (SiOx, 0 < x ≤ 2) (SiO, e.g., FIG. 1 and ¶ 0006; see also SiOx with varying oxidation states in Table 1) containing a lithium compound (Li2O embedded into SiO, e.g., ¶ 0005 and 0007); and a shell (carbon coating, FIG. 1) comprising amorphous carbon (carbon source of, e.g., pitch, i.e., amorphous carbon, ¶ 0062), positioned on, surrounding, and directly contacting the core (FIG. 1); wherein the silicon oxide comprises a lithium silicate of Li4SiO4 in at least a part of the silicon oxide (phase formed after lithiating SiO—and, thus, it is submitted, would necessarily be in at least part of SiO—e.g., ¶ 0003 and 0007).
Yang further discloses a D50, i.e., average particle size, of the SiOx (with embedded nano-Si) of ≤ 10.0 μm (¶ 0010) but fails to explicitly disclose 5–10 μm.
Yang is analogous prior art to the claimed invention because they pertain to the same field of endeavor, namely negative electrode material.
In incorporating the SiOx with an average particle size ≤ 10 μm, this range overlaps the recited 5–10 μm such that one skilled in the art could routinely select within the overlap with a reasonable expectation of forming a successful, appropriately sized active material (MPEP 2144.05 (I)).
Yang further discloses that the shell has an average thickness of ~ 8 nm (note general preference of 6~10 nm thickness and, thus, average of ~ 8 nm, ¶ 0042; see also, e.g., average thickness of 5 nm in Ex. 5, ¶ 0080), which falls within 0.1–10 nm (claim 1) and 0.1 nm to less than 10 nm (claim 22).
Yang further discloses the desire to limit SiOx’s volume expansion (e.g., ¶ 0003), as well as the ability to include other materials within the core (FIG. 1’s nano-Si), but fails to explicitly disclose that the core comprises a graphitic material with an average particle size of 3–15 μm.
Park, in teaching a core-shell anode active material (Title, FIG. 1), teaches that the core includes flake—i.e., natural—graphite particles 12 (first carbon particles) mixed with active particles 11 of, e.g., SiOx (FIG. 1, ¶ 0043 and 0058). Park teaches that the first carbon particles, i.e., graphite, improve the active material’s conductivity while assisting in uniformly dispersing the active particles (¶ 0061), which improves cycle life (¶ 0070). Park further teaches that the flake graphite’s average diameter is preferably 2–7 μm because this range allows pores with appropriate porosity to form in the core, improving buffering for active-material volume expansion and improving cycle life as the active particles are uniformly dispersed (¶ 0070).
Park is analogous prior art to the claimed invention because they pertain to the same field of endeavor, namely negative electrode material.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to incorporate Park’s flake/natural graphite into Yang’s core with the reasonable expectation of improving the active material’s conductivity while assisting in uniformly dispersing the active particles, as taught by Park. It would have been further obvious to incorporate the graphite with an average particle diameter of 2–7 μm, as taught by Park, and optimize within this range and the overlap—i.e., 3–7 μm for claim 1 and 2–7 μm for claim 22—to achieve optimal pore formation for volume-expansion buffering and active-material dispersion, as taught by Park (MPEP 2144.05 (II)).
As noted above, Yang discloses that the lithium silicate comprises Li4SiO4 for improved cycling performance (¶ 0003) but fails to explicitly disclose that the silicate also comprises at least one of Li2SiO3 and Li2Si2O5.
Hirose, in teaching a negative active material containing a silicon compound particle (Abstract), teaches that the compound particle contains a Li compound of at least one of Li2Si2O5, Li2SiO3, and Li4SiO4 (¶ 0080), teaching that the battery properties such as irreversible-capacity generation are further improved when the compound particle contains at least two of the silicates (¶ 0080, 0081).
Hirose is analogous prior art to the claimed invention because they pertain to the same field of endeavor, namely Si-based negative active material.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to additionally incorporate Li2Si2O5 and/or Li2SiO3 alongside Yang’s Li4SiO4, as taught by Hirose, with the reasonable expectation of further improving the battery’s properties, as taught by Hirose. Further, one skilled in the art would have reasonably expected that combining at least two of the silicates would achieve a successful silicate phase and contribute to an overall successful active material (see, e.g., MPEP 2144.06 (I)).
Although Yang is silent to the weight ratio of Li4SiO4 and, thus, fails to explicitly disclose the recited ≤ 10 parts by weight Li4SiO4 with respect to 100 parts by weight of the silicon oxide, Yang discloses that silicon oxides such as SiO provide long cycle life and low cost (¶ 0002) while further disclosing controlling the content of Li4SiO4 to maximize SiO’s volume buffering at a controllable capacity cost (¶ 0007). To balance these effects, then, it would have been obvious to routinely optimize the Li4SiO4:silicon oxide weight ratio (MPEP 2144.05 (II)).
Modified Yang further discloses that 90~99% of the reductant’s oxidation product—e.g., Li2O, i.e., the lithium compound—is ultimately removed (Yang, ¶ 0058), further disclosing controlling the content of Li2O and Li4SiO4 to maximize volume buffering at a controllable capacity cost (Yang, ¶ 0007), but fails to explicitly disclose the recited A/B (lithium wt%/lithium silicate wt%) of 0.020 or more.
The skilled artisan, however, in conforming to Yang’s 90~99% oxidation-product removal—and, thus, lithium removal—would recognize that a compromise necessarily exists between the Li2O and Li4SiO4’s volume-expansion buffering and the oxidation product’s removal. To balance such buffering while still conforming to Yang’s embodiment, then, it would have been obvious to routinely optimize the recited A/B ratio (MPEP 2144.05 (II)).
Additionally or alternatively, Kang, in teaching a negative active material including a silicon-based composite including lithium silicate (Title, ¶ 0011, 0012, 0027), teaches a lithium content of 2–15 parts by weight based on 100 parts by weight of the silicon oxide (¶ 0024)—which appears to fall well within or at least significantly overlap the recited A/B of ≥ 0.020 lithium:lithium silicate even when accounting for small mass differences between the (bulk) silicon oxide and the lithium silicate. Importantly, Kang teaches that < 2 parts by weight may fail to improve initial efficiency, while > 15 parts by weight may form unwanted lithium silicate from excessive lithium (¶ 0024).
Kang is analogous prior art to the claimed invention because they pertain to the same field of endeavor, namely Si-based negative active material.
To balance improving the active material’s initial efficiency with preventing unwanted lithium silicate’s forming from excessive lithium—all while accounting for Li4SiO4’s volume-expansion buffering—it would have been obvious to routinely optimize the recited A/B, as suggested by Kang (MPEP 2144.05 (II)).
It is submitted that the above disclosure further reads on the following:
(claims 2 and 17) the lithium compound is Li2O (Yang, ¶ 0007);
(claim 6) the graphitic material is natural graphite (Park’s flake/natural graphite).
Regarding claims 5 and 18, modified Yang discloses the negative electrode active material according to claim 1.
As noted in claim 1, modified Yang further discloses a carbon shell that may be pitch-based and, thus, amorphous (Yang, ¶ 0042), as well as the ability to include other materials within the core (per Yang’s FIG. 1’s nano-Si and Park’s graphite) but fails to explicitly disclose that the core further comprises amorphous carbon, and the amorphous carbon included in the shell is the same material as the amorphous carbon included in the core.
Park further teaches including a first amorphous carbon 13 in the core and a second amorphous carbon 17 in the shell (FIG. 1, ¶ 0043), where each amorphous carbon may be sourced from the same material such as pitch (¶ 0093, 0094). Park teaches that the first amorphous carbon strengthens bonding between the first carbon particles, i.e., graphite, and active particles and increases the core’s filling density (¶ 0075), which increases the electrode’s volumetric capacity (¶ 0080).
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to further incorporate a pitch-based amorphous carbon into Yang’s core—so that the shell and core’s amorphous carbons would be the same—as taught by Park, with the reasonable expectation of strengthening bonding between the graphite and active particles while improving the electrode’s volumetric capacity by increasing the core’s filling density, as taught by Park.
Regarding claim 7, modified Yang discloses the negative electrode active material according to claim 1.
Modified Yang further discloses a weight ratio of the carbon coating to SiOx/Si of preferably 12.5~20% (Yang, ¶ 0063)—and, thus, a total weight percentage of the SiOx/Si of 83.3~88.9%—but fails to explicitly disclose that the SiOx itself accounts for 5–50 wt% based on 100 wt% of the core-shell composite.
Yang further discloses, however, that the SiOx, specifically SiO, provides long cycle life at low cost (¶ 0002), while increasing the ratio of silicon in the lower oxidation states—e.g., Si0, i.e., elemental Si—improves cycle stability and obtains larger irreversible capacity (¶ 0095 and Table 1). To balance these effects, then—all while accounting for Park’s graphite’s enhancing conductivity and active-material dispersibility—it would have been obvious to routinely optimize the SiOx content with respect to the total weight of the composite (MPEP 2144.05 (II)).
Alternatively, Park further teaches including the active particles, i.e., SiOx, at preferably 5–40 wt% of the core because this range increases reversible capacity while facilitating volume-expansion buffering (¶ 0060).
It would have been obvious to the skilled artisan to incorporate the SiOx particles at 5–40 wt% of the core—which appears to at least significantly overlap the recited 5–50 wt% of the composite because the nanometer shell would contribute relatively little weight content—as taught by Park, and routinely optimize within this range and the apparent overlap to balance higher reversible capacity with proper volume-expansion buffering, as taught by Park (MPEP 2144.05 (II)).
Regarding claim 8, modified Yang discloses the negative electrode active material according to claim 1 but is silent to the graphite’s wt% and, thus, fails to explicitly disclose that the graphitic material comprises 30–80 wt% based on 100 wt% of the core-shell composite.
Modified Yang further discloses, however—as noted in claim 1—that the graphite enhances conductivity and active-material dispersibility. Yang further discloses that the SiOx, specifically SiO, provides long cycle life at low cost (¶ 0002), while increasing the ratio of silicon in the lower oxidation states—e.g., Si0, i.e., elemental Si—within the composite improves cycle stability and achieves higher reversible capacity (¶ 0095 and Table 1). To balance these effects, then, it would have been obvious to routinely optimize the graphite’s content with respect to the total weight of the composite (MPEP 2144.05 (II)).
Alternatively, Park further teaches including the first carbon particles, i.e., graphite, at preferably 10–70 wt% of the core because this range allows pores with appropriate porosity to form, improving volume-expansion buffering (¶ 0074), as discussed in claim 1.
It would have been obvious to the skilled artisan to incorporate the SiOx particles at 10–70 wt% of the core—which reasonably significantly overlaps the recited 30–80 wt% of the composite because the nanometer shell would contribute relatively little weight content—as taught by Park, and routinely optimize within this range and the apparent overlap to achieve optimal pore formation for volume-expansion buffering, as taught by Park (MPEP 2144.05 (II)).
Regarding claim 10, modified Yang discloses the negative electrode active material according to claim 1, wherein the core-shell composite is comprised at 100 wt% of the negative electrode active material (per Yang’s examples, ¶ 0073–0080, the composite constitutes 100 wt% of the negative active material), which falls within 50 wt% or more.
Claim(s) 3 and 4 is/are rejected under 35 U.S.C. 103 as being unpatentable over Yang et al. (US 20160079591 A1) (Yang) in view of Park et al. (KR 20140085822 A) (Park), Hirose et al. (US 20190229332 A1) (Hirose), and Kang et al. (US 20140205907 A1) (Kang), as applied to claim 1, taken alone or further in view of Kizaki (US 20120085974 A1).
Regarding claims 3 and 4, modified Yang discloses the negative electrode active material according to claim 1 but is silent to the recited Raman peaks.
However, because modified Yang discloses a substantially similar core-shell material compared to the instant disclosure (as seen throughout claims), the skilled artisan would have reasonably expected modified Yang’s silicon oxide’s maximal Raman peaks to exist at wavenumbers falling within or at least overlapping the recited 460–500 cm-1 (claim 3) and 500–530 cm-1 (claim 4), per MPEP 2112.01 (I). Such overlap would render the recited ranges obvious such that one skilled in the art could routinely select within the overlap with a reasonable expectation of forming a successful active material (MPEP 2144.05 (I)).
Alternatively, the instant specification notes that peaks at 461–471 cm-1 indicate insignificant nanocrystalline Si phase formation, whereas peaks at ≥ 500 cm-1 promote such phase formation (¶ 00175, Table 3). Importantly, Yang further discloses that SiOx, specifically SiO, provides long cycle life at low cost (¶ 0002), while increasing the ratio of silicon in the lower oxidation states—e.g., Si0, i.e., elemental Si (which is embedded into the SiOx, per Yang’s FIG. 1)—improves cycle stability and obtains larger irreversible capacity (0095 and Table 1). To balance these effects, then, it would have been obvious to routinely optimize the nano-Si content relative to the total SiOx/Si content—and, thus, necessarily control the Raman peaks (MPEP 2144.05 (II)).
Further alternatively, Kizaki, in teaching a silicon oxide negative electrode material (Title), teaches that the silicon oxide displays maximal peaks at 420 ± 5 cm-1, 490 ± 10 cm-1, and 520 ± 5 cm-1 (peaks A, B, and C, respectively, ¶ 0027 and FIG. 2). Kizaki teaches that silicon oxide with A/B > 0.5 and C/B < 2.0 exhibits excellent cycle characteristics compared to silicon oxide not satisfying these ranges (¶ 0027).
Kizaki is analogous prior art to the claimed invention because they pertain to the same field of endeavor, namely negative electrode material.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to control Yang’s SiOx’s Raman peaks to satisfy Kizaki’s relations—and, thus, display maximal Raman peaks within each recited range—with the reasonable expectation of affording the SiOx excellent cycle characteristics, as taught by Kizaki.
Claim(s) 11–15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Yang et al. (US 20160079591 A1) (Yang) in view of Park et al. (KR 20140085822 A) (Park), Hirose et al. (US 20190229332 A1) (Hirose), and Kang et al. (US 20140205907 A1) (Kang), as applied to claim 1, further in view of Yayamoto et al. (US 20140234705 A1) (Yayamoto).
Regarding claims 11–13 and 15, modified Yang discloses a method of preparing the negative electrode active material according to claim 1 (Yang, e.g., ¶ 0045–0049 and examples of ¶ 0073–0080), the method comprising step a) preparing the silicon oxide containing the lithium compound (milling SiO with metal reductant of, e.g., Li, ¶ 0047 and 0056), wherein the silicon oxide includes [the] lithium silicate of Li4SiO4 as well as Li2SiO3 and/or Li2Si2O5 in at least part of the silicon oxide (Yang’s Li4SiO4 plus Hirose’s Li2SiO3 and/or Li2Si2O5, as discussed in claim 1). Additionally, with respect to the recited Li4SiO4:silicon oxide weight ratio, such appears routinely optimizable to balance Li4SiO4 and silicon oxide’s effects, as further discussed in claim 1.
Modified Yang further discloses step b) compounding the silicon oxide containing the lithium compound, the graphitic material, and a carbon precursor of the amorphous carbon to prepare a core-shell composite precursor (note coating—and, thus, reasonably “compounding”—carbon precursor such as pitch, i.e., amorphous carbon onto SiOx (milled with reductant of, e.g., Li to form the “lithium compound” in Yang, ¶ 0047), Yang, ¶ 0062; note that the SiOx would also reasonably be compounded with Park’s graphite when milling with the reductant to incorporate the graphite into the core).
Modified Yang further discloses that there are various carbon-coating methods in the art, including CVD and pyrolysis (¶ 0062), yet, while not appearing limited to these methods to achieve the desired coating, fails to explicitly disclose 1) that the compounding in step b) comprises dry mixing with a shear stress and a centrifugal force applied, where the carbon precursor is introduced in the middle of the dry mixing. Additionally, modified Yang fails to explicitly disclose 2) step c) heat-treating the core-shell composite precursor to prepare the core-shell composite.
Regarding 1), Yayamoto, in teaching a negative electrode active material (Title), teaches coating carbon on SiOx via CVD or mechanofusion (¶ 0047).
Yayamoto is analogous prior art to the claimed invention because they pertain to the same field of endeavor, namely negative electrode material.
As Yang appears to afford no technical preference to CVD coating and Yayamoto recognizes CVD and mechanofusion as equivalent C-coating methods, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to routinely substitute Yang’s CVD with Yayamoto’s mechanofusion with a reasonable expectation of successfully coating the active material (MPEP 2143 (B.) and 2144.06 (II)).
Thus, modified Yang would disclose that the compounding in step b) comprises dry mixing with a shear stress and a centrifugal force applied (Yayamoto’s mechanofusion—which would seemingly be dry mixing because Yang dries the SiOx/Si before C-coating in ¶ 0060 and examples—which, in being substantially similar to the instant spec.’s mechanofusion treatment (e.g., ¶ 0075), would necessarily exert centrifugal force and shear stress (MPEP 2112.01 (I)).
Modified Yang is silent to the time at which the carbon precursor is introduced in step b) and, thus, fails to specify introducing in the middle of dry mixing.
The instant specification, however, broadly defines “middle” as 10–90% of cumulative time (¶ 0076). One skilled in the art would appreciate that adding the precursor too early would necessarily disrupt the coating process and, thus, coating quality, whereas introducing too late would necessarily slow production. To balance these effects, then, it would have been obvious to routinely optimize the point at which the carbon precursor is introduced (MPEP 2144.05 (II)).
Regarding 2), Park further teaches a heat treatment after ball-milling the core-shell composite (e.g., ¶ 0092, 0121 and 0122), where heating occurs at preferably 800–1500°C in an inert atmosphere (¶ 0096, 0097). Park teaches that heating within this range allows the active particles to exhibit excellent reactivity with lithium, and the amorphous-carbon precursor may be sufficiently carbonized, improving cycle life (¶ 0096).
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to heat modified Yang’s composite precursor at 800–1500°C in an inert atmosphere after milling, as taught by Park, with the reasonable expectation of improving cycle life by allowing the active particles to exhibit excellent reactivity with lithium and enabling the amorphous-carbon precursor to be sufficiently carbonized, as taught by Park.
It is submitted that the above disclosure further reads on the following:
(claim 12) wherein the compounding in step b) is performed by a mechanochemical treatment (mechanofusion, per Yayamoto);
(claim 13) wherein step c) is performed under an inert atmosphere (see inert gases in Park, ¶ 0097);
(claim 15) wherein the lithium compound is Li2O (Yang, e.g., ¶ 0007; see also, e.g., ¶ 0058).
Regarding claim 14, modified Yang discloses the method of preparing the negative electrode active material according to claim 11, wherein step a) is mixing and heat-treating a silicon compound and a lithium precursor (milling SiO and reductant such as Li, i.e., a lithium precursor, followed by drying at 50~100°C in Yang, ¶ 0060 and examples; note that the broadest reasonable interpretation of “heat-treating” appears to include the elevated drying temperature absent additional recitation or special definition).
Claim(s) 23 is/are rejected under 35 U.S.C. 103 as being unpatentable over Shin et al. (JP 2014199753 A) (Shin) in view of Park et al. (KR 20140085822 A) (Park) and Kang et al. (US 20140205907 A1) (Kang).
Regarding claim 23, Shin discloses a negative electrode active material for a lithium secondary battery (e.g., Abstract), the negative electrode active material comprising a core-shell composite (silicon compound core particles plus carbon coating, e.g., Abstract and ¶ 0046) comprising
a core comprising a silicon oxide (SiOx, 0 < x ≤ 2) (preferably SiO, e.g., ¶ 0036; see also Ex. 1, ¶ 0144).
Shin further discloses that the silicon oxide includes a continuous lithium silicate phase (e.g., Abstract, ¶ 0030), which may include other compounds such as LiOH (¶ 0034), but Shin fails to explicitly disclose an embodiment of such.
Shin is analogous prior art to the claimed invention because they pertain to the same field of endeavor, namely Si-based negative active material.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to routinely incorporate lithium hydroxide into Shin’s lithium silicate phase—and, thus, achieve a silicon oxide containing a lithium compound of LiOH—with a reasonable expectation of forming a successful silicon oxide and lithium silicate phase (MPEP 2143 (A.) and 2144.06 (I)).
As seen above, Shin allows other materials to be present within the core, as well as desires to mitigate electrode volume expansion (e.g., ¶ 0038, 0047), but fails to explicitly disclose a graphitic material with an average particle size of 3–15 μm in the core.
Park, in teaching a core-shell anode active material (Title, FIG. 1), teaches that the core includes flake—i.e., natural—graphite particles 12 (first carbon particles) mixed with active particles 11 of, e.g., SiOx (FIG. 1, ¶ 0043 and 0058). Park teaches that the first carbon particles, i.e., graphite, improve the active material’s conductivity while assisting in uniformly dispersing the active particles (¶ 0061), which improves cycle life (¶ 0070). Park further teaches that the flake graphite’s average diameter is preferably 2–7 μm because this range allows pores with appropriate porosity to form in the core, improving buffering for active-material volume expansion and improving cycle life as the active particles are uniformly dispersed (¶ 0070).
Park is analogous prior art to the claimed invention because they pertain to the same field of endeavor, namely negative electrode material.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to incorporate Park’s flake/natural graphite into Shin’s core with the reasonable expectation of improving the active material’s conductivity while assisting in uniformly dispersing the active particles, as taught by Park. It would have been further obvious to incorporate the graphite with an average particle diameter of 2–7 μm, as taught by Park, and optimize within this range and the overlap to achieve optimal pore formation for volume-expansion buffering and active-material dispersion, as taught by Park (MPEP 2144.05 (II)).
Regarding the silicon oxide’s average particle size, Shin discloses an overall active-particle average size of preferably 0.2–20 μm (¶ 0049), which appears to be the approximate size of the silicon oxide particles as the main component in the “core”. Shin discloses that, within this range, specific surface area becomes large enough to preserve battery capacity while preventing battery characteristics from deteriorating and minimizing the risk of the electrode’s peeling off the current collector (¶ 0049).
Although Shin fails to explicitly embody an average size of 5–10 μm silicon oxide, to balance the above effects, it would have been obvious to routinely optimize the silicon oxide’s average particle size, including within the overlap (MPEP 2144.05 (II)).
Arguendo, however, if Shin’s active material’s size did not reference the silicon oxide’s average size, Park further teaches that the average diameter of the SiOx active particles in the core may be 1 nm to 5 μm because this range affords excellent active-particle dispersibility, increases reversible capacity, and suppresses volume expansion to improve cycle life (¶ 0058, 0059).
To balance active-particle dispersibility, increasing reversible capacity, and suppressing volume expansion, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to incorporate Shin’s silicon oxide particles with an average size of 1 nm to 5 μm and routinely optimize within this range and the overlap, as taught by Park (MPEP 2144.05 (II)).
Shin further discloses a shell positioned on, surrounding, and directly contacting the core (carbon surface coating, e.g., ¶ 0046 and Ex. 1).
Shin further discloses that the surface coating may use carbon materials such as amorphous graphite because such amorphous carbon experiences relatively small volume expansion, allowing it to mitigate the entire electrode’s volume expansion while being less susceptible to deterioration from crystal-grain boundaries and defects (¶ 0047), but Shin fails to explicitly disclose an embodiment of such amorphous carbon.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to routinely incorporate amorphous carbon as Shin’s shell with a reasonable expectation of forming a successful coating for mitigating the electrode’s volume expansion without deteriorating due to defects, as taught by Shin (e.g., MPEP 2143 (A.)).
Shin further discloses that the silicon oxide includes a lithium silicate for improving ion diffusivity and initial (dis)charge efficiency (¶ 0029), further exemplifying Li2SiO3, Li2Si2O5, and Li4Si4O4, where Li4Si4O4 is preferably the main component (¶ 0031, 0032), but fails to explicitly embody at least one of Li2SiO3 and Li2Si2O5 alongside Li4Si4O4.
It would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to routinely incorporate at least one of Li2SiO3 and Li2Si2O5 alongside Shin’s Li4Si4O4 with a reasonable expectation of forming a successful silicate phase to improve ion diffusivity and initial (dis)charge efficiency, as taught by Shin (e.g., MPEP 2143 (A.) and 2144.06 (I)).
Regarding the shell’s thickness, although Shin is silent to the value of such, as discussed above, Shin discloses that the amorphous carbon mitigates electrode volume expansion (¶ 0047), so the shell must necessarily be thick enough to exert this effect. The skilled artisan, meanwhile, would understand that the bulk of ion (de)intercalation would necessarily occur in the SiOx-based core as the active material, meaning that a too thick shell would necessarily impede electron and ion diffusion into and out of the core. To balance these effects, then, it would have been obvious to routinely optimize the shell’s average thickness (MPEP 2144.05 (II)).
Nonetheless, Kang, in teaching a negative active material with Si coated with carbon (Abstract), teaches a coating thickness ~ 5 nm (¶ 0022).
Kang is analogous prior art to the claimed invention because they pertain to the same field of endeavor, namely Si-based negative active material.
It would have been obvious to one of ordinary skill in the art, before the claimed invention's effective filing date, that Shin's shell must necessarily be incorporated with some thickness, and, as demonstrated by Kang, the skilled artisan would find it obvious to employ an average thickness of ~ 5 nm as a suitable dimension.
Regarding the Li4SiO4’s constituting ≤ 10 parts by weight with respect to 100 parts by weight of the silicon oxide, although Shin fails to explicitly articulate this ratio, Shin further discloses that the ratio of lithium silicate (of which Li4SiO4 is the main component) to silicon oxide is preferably 5–35 mol% (¶ 0040), which, even when accounting for small differences between mass and molar content, appears to encompass or significantly overlap the recited ≤ 10 parts by weight. More importantly, though, Shin discloses that Li4SiO4 is particularly chemically stable and particularly improves ion diffusion within the active material (¶ 0032), while silicon oxide provides high capacity and stable cycling (e.g., ¶ 0004, 0036). To balance these effects, then, it would have been obvious to routinely optimize the Li4SiO4:silicon oxide ratio (MPEP 2144.05 (II)).
Shin further aims to improve initial efficiency (e.g., ¶ 0004, 0017) but is silent to the lithium content relative the lithium silicate and, thus, fails to explicitly disclose the recited A/B of ≥ 0.020.
Kang further teaches that the SiOx active material is bound to lithium in the form of lithium silicate (¶ 0027), teaching 2–15 parts by weight lithium relative to 100 parts by weight of the coated SiOx (¶ 0024), a range that appears to encompass or significantly overlap the recited ≥ 0.020 even when accounting for small differences in mass content between SiOx and lithium silicate. Kang teaches that < 2 parts may fail to improve initial efficiency, while > 15 parts may form an unwanted amount of silicate from excessive lithium (¶ 0024). Moreover, as discussed above, Shin discloses that the lithium silicate improves ion diffusion in the active material while improving initial (dis)charge efficiency (¶ 0030).
To balance improving initial efficiency with preventing forming an unwanted amount of silicate—all while accounting for lithium silicate’s technical effects—it would have been obvious to routinely optimize the lithium:lithium silicate ratio, as suggested by Kang (MPEP 2144.05 (II)).
Response to Arguments
Applicant’s arguments with respect to claim(s) 1, 11, 22, and 23 have been fully considered. Applicant’s amendment overcame the previous 35 U.S.C. 103 rejection—which, as noted above, has been withdrawn—and necessitated the new grounds of rejection citing the new references Hirose and Kang. Examiner respectfully disagrees with Applicant’s arguments relevant to the still-applied Yang and Park references as follows:
Applicant argues that because Yang’s Li4SiO4 forms by lithiating the completed active material versus through pre-lithiation, the skilled artisan cannot recognize Applicant’s improved slurry stability and life characteristics by preventing a residual lithium compound’s elution, further arguing that the artisan would also fail to realize this advantage in consulting Park because Park is also not directed toward pre-lithiation. Examiner respectfully argues that such arguments are incommensurate with the independent claims, which merely require at least one of Li2SiO3 and Li2Si2O5 and, optionally, Li4SiO4 in the core’s silicon oxide. Regardless of whether these silicate phases form via pre-lithiation, as Yang discloses Li4SiO4 in the core, while Hirose motivates including at least two forms of Li2SiO3, Li2Si2O5, and Li4SiO4 for further improved battery characteristics, such appears to constitute proper prima facie obviousness in incorporating Li2SiO3 and/or Li2Si2O5 alongside Li4SiO4 in Yang’s core. Thus, this argument is unpersuasive.
Applicant further argues that because neither Yang nor Park is directed toward pre-lithiation, the recited A/B ratio reflecting lithium content in the composite is unobtainable. Examiner respectfully disagrees and, as discussed above, reiterates that Yang discloses that 90~99% of the reductant’s oxidation product—e.g., Li2O, i.e., the lithium compound—is ultimately removed (¶ 0058), further disclosing controlling the content of Li2O and Li4SiO4 to maximize volume buffering at a controllable capacity cost (Yang, ¶ 0007). The skilled artisan, then, in conforming to Yang’s 90~99% oxidation-product removal—and, thus, lithium removal—would recognize that a compromise necessarily exists between the Li2O and Li4SiO4’s volume-expansion buffering and the oxidation product’s removal. To balance such buffering while still conforming to Yang’s embodiment, then, the A/B ratio appears optimizable.
Additionally or alternatively, as outlined above, Kang teaches a lithium content of 2–15 parts by weight based on 100 parts by weight of silicon oxide (¶ 0024)—which appears to fall well within or at least significantly overlap the recited A/B of ≥ 0.020 lithium:lithium silicate even when accounting for small mass differences between the (bulk) silicon oxide and the formed lithium silicate. Importantly, Kang teaches that < 2 parts by weight may not improve the initial efficiency, while > 15 parts by weight may form unwanted lithium silicate from excessive lithium (¶ 0024).
Thus, Examiner respectfully submits that the skilled artisan would be motivated to control the lithium content relative to the lithium silicate content based on MPEP 2144.05 (II), absent demonstrated criticality to the A/B ratio. Though the prior art may not explicitly recognize Applicant’s prevention of lithium elution based on A/B, per MPEP 2145 (II), Applicant’s recognizing an advantage that would flow naturally from following the suggestion of the prior art cannot be the basis for patentability when the differences would otherwise be obvious.
Nonetheless, in considering whether the A/B ratio is potentially unexpected and superior to the prior art, Examiner respectfully observes that only one comparative example tests outside the recited A/B of ≥ 0.020 (Comp. Ex. 3 (Table 4) with A/B of 0.01), although Comp. Ex. 3’s battery characteristics were not further evaluated, and, thus, this sample’s performance is incomparable to Applicant’s working examples. Per MPEP 716.02(d), to establish unexpected results over a claimed range, Applicant should compare a sufficient number of tests both inside and outside the claimed range to show criticality across the range. Thus, as the performance effect of an A/B below 0.020 is indeterminable based on the data of record, it is unclear that an A/B ≥ 0.020 is truly critical, unexpected, and unobtainable by the prior art, rendering this argument unpersuasive.
Moreover, even if the A/B ≥ 0.020 were critical, Examiner respectfully notes that such results appear incommensurate with the independent claims. The scope of each of claims 1 and 22 is drawn to a negative active material, whereas Applicant’s adhesive strength stems from incorporating the active material into a negative electrode slurry coated onto a current collector (instant spec., ¶ 0116, 0135). Additionally, Applicant’s interfacial resistance stems from incorporating the above electrode into a lithium half-cell (as seen in current and voltage through electrode in instant spec., ¶ 0118/0130). Further, as Applicant acknowledges, the A/B suppresses electrolytic side reactions during (dis)charge (Remarks, p. 10; see instant spec., ¶ 0007 and 0200), an effect that can only occur after assembling the active material into a negative electrode that is incorporated into a battery. As MPEP 716.02(d) requires unexpected results to be commensurate with the claimed scope, this argument is further unpersuasive.
Regarding new claim 23, see the necessitated new grounds of rejection above.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/J.S.M./Examiner, Art Unit 1751
/JONATHAN G LEONG/Supervisory Patent Examiner, Art Unit 1751 8/26/2025
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