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 01/09/26, have been fully considered. Claim(s) 1, 6, 7, and 9 is/are amended; claim(s) 5, 8, and 10 stand(s) as originally or previously presented; and claim(s) 2–4 is/are canceled; no new matter has been added. Examiner affirms that the original disclosure provides adequate support for the amendment.
Upon considering said amendment and arguments, the previous claim objections as well as 35 U.S.C. 102 rejections over Pei and Chen, set forth in the Office Action mailed 10/09/25, has/have been withdrawn. However, the previous 103 rejection over Chen has/have been maintained and altered as necessitated by Applicant’s amendment, as set forth below. Additionally, Applicant’s amendment necessitated the new grounds of rejection below over Forbert in view of Chen.
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, 5, 6, 9, and 10 is/are rejected under 35 U.S.C. 103 as being unpatentable over Chen et al. (WO 2022057919 A1; citations to English equivalent US 20230223534 A1) (Chen).
Regarding claims 1 and 10, Chen discloses a lithium secondary battery (lithium manganese iron phosphate (LMFP) battery, e.g., ¶ 0049, 0057–0059), comprising a cathode and an anode facing the cathode (facing neg. and pos. electrodes, respectively, e.g., ¶ 0057–0059), the cathode comprising a cathode active material (LMFP, e.g., Ex. 6 of Table 1), comprising first lithium metal phosphate particles having a shape of a secondary particle formed by aggregation of primary particles (aggregated LFP Particle 1 of Ex. 6, Table 1), the first lithium metal phosphate particles having an average particle diameter (D50) of 8 μm (Id.), falling within 5–10 μm.
Chen further discloses single-crystal-like LMFP Particles 4 and 5 (Id.), which, in being composed of 1–5 primary particles with few internal grain boundaries (¶ 0004), read on the instant second and third single particles, respectively, based on the instant specification’s ¶ 0043. Chen discloses a D50 ratio of Particle 1:4:5 of 1:0.15:0.12 in Ex. 6 (see also Abstract for this relation), respectively yielding instant second and third D50 values of 1.2 μm and 0.96 μm, which respectively fall within 1–3 μm and less than 1 μm.
Chen further discloses that the mass ratio between the first, fourth, and fifth LMFP particles—instant first–third materials, respectively—may be 100:0.5:0.3 (¶ 0026) yet, while not appearing necessarily limited to this precise range to achieve the desired electrode besides clearly desiring a vast majority of the first material (note Chen’s disclosing no technical preference for this range), fails to explicitly disclose the recited 50–70 wt% first material, 20–40 wt% second material, and 10–30 wt% third material.
Chen further discloses, however, that different morphology and D50 values of the LMFP affect the path length for Li+ diffusion, Mn dissolution, and cycle stability (¶ 0018), disclosing that the aggregated first LMFP includes small-sized primary particles, which afford a short path for Li+ diffusion (as well as increase capacity, ¶ 0004), but the many grain boundaries increase the Li ion’s energy barrier (¶ 0018). Meanwhile, the single-crystal fourth and fifth LMFP (2nd/3rd) have fewer grain boundaries and, thus, a small diffusion energy barrier (as well as decrease Mn dissolution, which otherwise degrades cycle performance, ¶ 0004) but include a large primary particle size and, thus, a long path for Li+ diffusion (¶ 0018).
Considering that Chen is analogous prior art to the claimed invention because they pertain to the same field of endeavor, namely lithium-metal-phosphate cathode active material, to balance suitable Li+ diffusion into/out of each particle with proper Mn dissolution and cycle stability, it would have been obvious to reach the instant ratio by routinely optimizing the weight ratios of the first, second, and third lithium metal phosphate particles (MPEP 2144.05 (II)).
Regarding claim 5, Chen discloses the cathode active material for a lithium secondary battery according to claim 1, wherein the primary particles have an average particle diameter of 200 nm (Ex. 6, Table 1), falling within 10–500 nm.
Regarding claims 6 and 9, Chen discloses the cathode active material for a lithium secondary battery according to claim 1, wherein the first lithium metal phosphate further comprise a carbon coating formed on a surface of the secondary particle (carbon cladding atop first (aggregated) LMFP particle, e.g., ¶ 0027; in being externally coated, such would reasonably form on a surface of the secondary particle), and the second lithium metal phosphate particles and the third lithium metal phosphate particles comprise a carbon coating formed on surfaces thereof (per ¶ 0027, the carbon cladding may also be applied to the fourth and fifth (2nd/3rd) LMFP particles).
Claim(s) 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over Chen et al. (WO 2022057919 A1; citations to English equivalent US 20230223534 A1) (Chen), as applied to claim 1, as evidenced by Zhao (Lithium Manganese Iron Phosphate (LMFP) Batteries Receiving Renewed Attention In China ― Expected to Be Installed Mainly in Middle-Class EVs).
Regarding claim 7, Chen discloses the cathode active material for a lithium secondary battery according to claim 1, wherein the first, second, and third lithium metal phosphate particles have an olivine structure (as evidenced by Zhao, first ¶ of p. 2, LMFP is olivine) and are represented by the recited Chemical Formula 1, where a = x = y = 1, M = Fe and Mn, and z = 0 (LiMn0.65Fe0.35PO4, Chen’s ¶ 0052).
Claim(s) 1 and 5–10 is/are rejected under 35 U.S.C. 103 as being unpatentable over Forbert et al. (WO 2022208049 A1) (Forbert) in view of Chen et al. (WO 2022057919 A1; citations to English equivalent US 20230223534 A1) (Chen).
Regarding claims 1 and 5–10, Forbert discloses a lithium secondary battery (e.g., top of p. 1 and exs.) comprising a cathode and an anode facing the cathode (necessarily for ion intercalation, as in p. 17, line 35, and p. 18, lines 4–6), the cathode comprising a cathode active material (lithium iron phosphate (LFP) composition, e.g., p. 2, lines 13–15, and Ex. 1, pp. 19–21).
Forbert discloses that the active material includes secondary particles (carbon-coated particles of micro-agglomerated LFP comprising agglomerates of primary particles, e.g., p. 2, lines 13–17, p. 7, lines 16–18, and Ex. 1, pp. 19 and 20) and single particles (carbon-coated particles of powder LFP (Id.), which, per p. 7, lines 20 and 21, may be in the form of essentially primary particle and, thus, unaggregated “single particles”), where the micro-agglomerated LFP may further include a plurality of primary/unaggregated particles (p. 7, lines 16–18). Thus, the micro-agglomerates would correspond to the “first lithium metal phosphate particles”; the primary particles included with the micro-agglomerates would correspond to the “second lithium metal phosphate particles”; and the primary particles in the powder LFP would correspond to the “third lithium metal phosphate particles”.
Forbert discloses that the micro-agglomerates/plurality of primary particles (i.e., first and second particles) typically have a D50 of 0.8~7 μm, while the powder particles (third particles) typically have a smaller D50 of 0.1~0.5 μm (p. 7, lines 23–33). Such small-particle D50 of 0.1~0.5 μm satisfies a third D50 < 1 μm.
Forbert further desires denser cathodes with improved gravimetric capacity (e.g., p. 1, lines 15–17), though Forbert fails to specify first and second D50s of 5–10 μm 1–3 μm, respectively.
Chen teaches a cathode active material including first–fifth lithium metal phosphate particles including aggregated, secondary particles with larger D50s and single-crystal particles with smaller D50s (e.g., Abstract, Ex. 6). Chen exemplifies a largest D50 of 8 μm in the largest aggregated particles, a D50 of 1.84 μm in the largest single-crystal particles, and a D50 of 0.96 μm in the smallest single-crystal particles (e.g., Ex. 6 based on particle-size ratios of Particles 1, 3, and 5, respectively). Chen teaches that using this combination of differently sized particles achieves an active material with high compaction density, high capacity, and high cycle stability (¶ 0005).
Chen and Forbert are analogous prior art to the claimed invention because they pertain to the same field of endeavor, namely LMP 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 select first and second D50s of the first and second lithium metal phosphate particles of 8 μm and 1.84 μm, respectively (falling within 5–10 μm and 1–3 μm, respectively), as suggested by Forbert’s broader range and more explicitly taught by Chen, with the reasonable expectation of achieving high compaction density, capacity, and cycle stability, as taught by Chen and desired by Forbert.
Regarding the weight ratios of 50–70 wt% first particles, 20–40 wt% second particles, and 10–30 wt% third particles based on a total weight of the first through third particles, Forbert generally discloses that the mixture of micro-agglomerates and powder particles affords higher electrode density and capacity than ones consisting of aggregates or powders (Tables 2 and 3 and p. 23, lines 5–9). Further, Chen teaches that different morphology and D50 values of the lithium metal phosphates affect the path length for Li+ diffusion and cycle stability (¶ 0018), where the aggregates small-sized primary particles—as in Forbert’s micro-aggregates of primary particles/first particles—which afford a short path for Li+ diffusion (as well as increase capacity, ¶ 0004), but the many grain boundaries increase the Li ion’s energy barrier (¶ 0018). Meanwhile, Chen teaches that the progressively smaller single-crystal particles (instant 2nd/3rd) have fewer grain boundaries and, thus, a small diffusion energy barrier but include a large primary particle size and, thus, a long path for Li+ diffusion (¶ 0018). To balance these effects, then, it would have been obvious to arrive at the recited first:second:third ratio by routinely optimizing the weight ratios of each set of phosphate particles (MPEP 2144.05 (II)).
It is submitted that the above disclosure further reads on the following:
(claim 5) the primary particles have an average particle diameter of 0.1~0.5 μm (Forbert, p. 7, lines 25 and 26), i.e., 100~500 nm, falling within 10 nm–500 nm;
(claims 6 and 9) at least one of the first lithium metal phosphate particles further comprises a carbon coating formed between the primary particles or on a surface of the secondary particle, and the second lithium metal phosphate particles and the third lithium metal phosphate particles comprise a carbon coating formed on respective surfaces thereof (by C-coating each set of particles—and, thus, necessarily between primary particles and/or on surface of secondary particle—as in Forbert’s p. 7, lines 16 and 20);
(claims 7 and 8) each of the first–third lithium metal phosphate particles has an olivine structure (Forbert, p. 1, line 10) and is represented by Chemical Formula 1, where a = x = y = 1, z = 0, and M is Fe, wherein the first–third lithium metal phosphate particles include LiFePO4 (LFP, i.e., LiFePO4, in Forbert’s Ex. 1, pp. 19 and 20).
Response to Arguments
Applicant’s arguments, with respect to claim 1, against Pei and Chen have been fully considered. Although arguments against Pei are persuasive based on the amendment, Examiner respectfully disagrees with the arguments against Chen (and ones applicable to Forbert) as follows:
Applicant argues that Chen’s particle-quantity ratio teaches away from the instant ranges. Examiner respectfully notes that the above rejection does not cite this ratio because such would not necessarily reflect the mass ratio given the particles’ varying sizes, rendering this argument—and auxiliary arguments based on this rationale—unpersuasive. Rather, as previously explained, Chen discloses an exemplary mass ratio (¶ 0020) but provides no technical significance to this range and, thus, does not appear strictly limited to such—besides clearly desiring a vast majority of the first active material—to achieve the desired energy density (see MPEP 2123 (II), where exemplary/alternative embodiments do not teach away without discrediting the solution).
More generally, Chen details that different morphology and D50 values affect the path length for Li+ diffusion, Mn dissolution, and cycle stability (¶ 0018), where the aggregated first LMFP includes small-sized primary particles, which afford a short path for Li+ diffusion (as well as increase capacity, ¶ 0004), but the many grain boundaries increase the Li ion’s energy barrier (¶ 0018). Meanwhile, the single-crystal fourth and fifth LMFP (2nd/3rd) have fewer grain boundaries and, thus, a small diffusion energy barrier (as well as decrease Mn dissolution, which otherwise degrades cycle performance, ¶ 0004) but include a large primary particle size and, thus, a long path for Li+ diffusion (¶ 0018). Absent demonstrated criticality, then, the skilled artisan would have routinely reached the instant ratios by optimizing the first:second:third ratio to balance these factors.
Applicant then asserts that claim 1’s active material achieves unexpectedly superior results. Examiner first notes that Chen’s positive electrode’s compaction density is 2.7–2.86 g/cc (Table 2), and Forbert’s is, e.g., 2.60 g/cc (Table 2, Ex. 1), both of which appear substantially similar to instant Table 1’s; thus, it appears that at least the instant density results would have been expected from the prior art. Nonetheless, Applicant alleges that Exs. 5, 6, and 9, with first-particle content < 50 wt%, as well as Ex. 7, with third-particle content < 10%, exhibit poorer results relative to other examples.
Examiner respectfully notes that in Ex. 5, both the first and second particles are outside their respective ratios, and in Exs. 7 and 9, both the first and third particles are outside their respective ratios. Thus, it is unclear if each example’s poorer performance is due to only one set of particles’ being outside its respective ratio or the combination of sets of particles’ being outside, and, thus, it is unclear that each of the instant ratios is truly critical.
Though Examiner agrees that Exs. 6 and 8 vary only one set of particles outside its respective ratio and exhibit poorer performance relative to, e.g., Exs. 1–4, such only respectively test the first and second particles below their respective ranges. As criticality demonstrations require testing both within and outside the range (MPEP 716.02(c))—and, thus, above and below the range—it remains unclear that the three ratios together are critical.
Arguendo, if each range were purported to not be individually critical but rely on a synergistic effect, then it appears that claim 1’s ranges are broader than Table 1’s data. For instance, taking Exs. 1–4 and 10 as the better-performing examples, it seems that such performance occurs when the third particles are limited to 10–20 wt%.
Further assuming, arguendo, that the results were unexpected and superior, the results appear incommensurate with claim 1 at least as follows:
Claim 1 allows any type of LMP particles, whereas the spec. embodies LiaMxPyO4+z, where M may be Fe, Co, Ni, Mn, Ti, and/or V (¶ 0047–0050), further detailing that an auxiliary dopant such as Al may be added to enhance the material’s chemical stability and capacity/power (¶ 0052, 0053); it is unclear if such results would occur using any LMP particles.
Each of the instant first–third particles may include a carbon coating to improve electrical conductivity and power (¶ 0039/0040, 0046; see also Ex. 1, ¶ 0086); it is unclear if such results would occur without any carbon coating given that claim 1 permits no coating.
Claim 1 permits any diameter of the primary particles forming the first LMP secondary particles, whereas the spec. embodies 10–500 nm for easily aggregating Li+ into the secondary particles while reducing the moving distance (¶ 0038); it is unclear if such results would occur for primary particles with diameter, e.g., 700 nm.
Claim 1 is to a cathode active material, whereas the capacity-retention and low-temperature-capacity results stem from incorporating the active material into a cathode incorporated into a lithium battery alongside an anode and a separator-permeated electrolyte (e.g., ¶ 0092–0096, 0108–0112).
Further, as the results are capacity-based, the skilled artisan would recognize that factors like the anode active material would affect the capacity (e.g., Si/SiOx anodes are well known to exhibit much higher capacity than graphite).
Along these lines, claim 1 (or 10) would allow any concentration of active material in either electrode, which would further dictate capacity. It is unclear if substantially similar results would occur at, e.g., 70% active material in each electrode as at 95%.
Similarly, claim 1 (or 10) would allow any concentration of conductive material and binder in either electrode (see, e.g., spec.’s ¶ 0092). As these components do not contribute to the redox reaction but affect the relative active-material content, it is unclear if substantially similar results would occur if the conductive material and binder each constituted, e.g., 10 wt% or 1 ppb.
Thus, per MPEP 716.02(d), this argument is further unpersuasive.
Conclusion
The cited art made of record but not relied upon is considered pertinent to Applicant’s disclosure:
US 20250309263 A1: positive electrode active material including three types of lithium iron phosphate (LFP) particles with first, second, and third diameters, with respective quantity ratios similar to the instant disclosure’s, though the particles are all (unaggregated) primary particles whose average sizes are out of range of claim 1’s respective D50s.
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 3/23/2026