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 .
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 06/26/26 has been entered.
Status of Claims
Applicant’s amendment and arguments, filed 06/26/26, have been fully considered. Claim(s) 1 is/are amended; claim(s) 5–10 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 35 U.S.C. 103 rejection over Chen as well as over Forbert in view of Chen has/have been maintained and altered as necessitated by Applicant’s amendment, as set forth below.
Claim Objections
Claim 9 is objected to for the following informality: in line 3, “metal phosphate particles comprise a carbon coating formed on respective surfaces thereof” should read “metal phosphate particles comprise a carbon coating formed on respective surfaces thereof” (i.e., the underline should be omitted) because this amendment was made in the claim set filed 01/09/26, so the status of claim 9 in the 06/26/26 claim set would be “Previously Presented”, as noted. Examiner notes that the retained underline of “respective” seems inadvertent, and the response otherwise appears to be a bona fide reply and, thus, appears complete.
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. 1 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. 1, Table 1), the first lithium metal phosphate particles having an average particle diameter (D50) of 4.5 μm (Id.), which, although narrowly outside 5–10 μm, is so close that the skilled artisan would have expected substantially similar performance (MPEP 2144.05 (I)).
Specifically, Chen never attributes poorer performance to this value (i.e., it is part of an inventive example), and there appears to be no criticality specifically to < 5 μm first particles based on the data of record. Thus, absent demonstrated criticality isolated to < 5 μm first particles, Chen’s value appears merely an obvious variant of the instant range.
Chen further discloses single-crystal-like LMFP Particles 3 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 1:3:5 of 1:0.23:0.16 in Ex. 1 (see also Abstract for this relation), respectively yielding instant second and third D50 values of 1.04 μm and 0.72 μm, which respectively fall within 1–3 μm and 0.1–0.8 μm.
Chen further discloses that the mass ratio between the first, third, and fifth LMFP particles—instant first–third materials, respectively—may be 100:2.5:0.3 (¶ 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 particles, 20–40 wt% second particles, and 10–30 wt% third particles based on a total weight of the first through third lithium metal phosphate particles.
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 third 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).
To balance suitable energy required for reaction kinetics with path length for Li+ diffusion, 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. 1, 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 third 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, 5, and 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 a) 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 b) 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 c) 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, further falling within claim 5’s 10–500 nm). Such small-particle D50 of 0.1~0.5 μm satisfies a third D50 of 0.1–0.8 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 and 1–3 μm, respectively.
Chen teaches an analogous 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. 1). Chen exemplifies a largest D50 of 4.5 μm in the largest aggregated particles, a D50 of 1.04 μm in the largest single-crystal particles, and a D50 of 0.72 μm in the smallest single-crystal particles (e.g., Ex. 1 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).
To balance high compaction density, capacity, and cycle stability, it would have been obvious to arrive at a first D50 of 5–10 μm and a second D50 of 1–3 μm by selecting a larger value of D50 from Forbert’s micro-aggregates’ broader range as the first D50 and a smaller value from within Forbert’s range as the second D50, 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).
Although Forbert fails to explicitly disclose 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, to balance the above effects, 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)).
Regarding claims 6 and 9, modified Forbert discloses the cathode active material for a lithium secondary battery according to claim 1, wherein 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).
Regarding claims 7 and 8, modified Forbert discloses the cathode active material for a lithium secondary battery according to claim 1, wherein 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 Chen and Forbert have been fully considered but are unpersuasive.
Applicant argues that Chen’s particles’ mass ratios are outside the respectively recited ranges. Examiner agrees but respectfully reiterates that Chen’s mass ratio in ¶ 0026 is exemplary and, thus, appears non-limiting besides clearly suggesting Chen’s desire for vast majority first/largest particles. Instead, the rejection is based on the concept that the skilled artisan would have been motivated to arrive at each recited range by controlling the particle 1:3:5 (instant 1:2:3) ratio to balance the effects of the particles (i.e., shortened ion diffusion paths but more grain boundaries and, thus, higher energy barrier in the primary particles of the first particles versus longer ion diffusion paths but lower energy barrier due to fewer grain boundaries in the progressively smaller, single-crystal second and third particles).
Applicant further argues that the above statement is too general to derive the instant mass ratios but is “merely a known technical common sense in the field” (Remarks, p. 10). Examiner agrees that such appears logical to one of ordinary skill in the art, and, thus, Examiner respectfully submits that such supports the case of obviousness. MPEP 2144.05 (II) clarifies that, absent demonstrated criticality, where the general conditions of a claim are disclosed, it is not inventive to discover the optimum ranges by routine experimentation. Here, Chen discloses the general conditions—larger, secondary particles alongside progressively smaller, single-crystal particles (with D50s corresponding to claim 1’s respective first–third particles)—and motivates the skilled artisan to routinely experiment to arrive at the instant mass ratios to achieve optimal compaction density, capacity, and cycle stability. Further, Examiner reiterates the response to the alleged criticality of the mass ratios below. Thus, the argument that Chen’s disclosure is too general is unpersuasive.
Applicant further argues that Chen only focuses on increasing capacity and energy density, not stability and capacity retention, whereas the instant mass ratios are designed to enhance capacity retention in harsh environments. Examiner respectfully disagrees because Chen explicitly tailors the D50s to reduce Mn dissolution and improve cycle stability (e.g., ¶ 0018). Moreover, even if Chen had not acknowledged cycle stability, Applicant’s recognizing another advantage that would flow naturally from following the prior art’s suggestions cannot be the basis for patentability when the differences would be otherwise obvious (MPEP 2145 (II)). Here, Chen recognizes not only cycle stability but also compaction density and capacity as other benefits of employing the varyingly sized particles, making this argument unpersuasive.
Applicant further argues that Chen’s particles’ sizes fail to correspond to the instant ranges. Examiner respectfully disagrees because, in contrast to the argument, Examiner now cites Chen’s Ex. 1, where the only size slightly outside is the first particles’ D50 of 4.5 μm versus 5–10 μm. However, as established above, Chen never attributes weaker performance to this value, and the evidence of record does not seem to support criticality isolated to < 5 μm first particles. Thus, this argument is unpersuasive.
Applicant further argues that claim 1’s active material achieves unexpectedly superior results. Examiner first echoes 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.
Applicant specifies that instant Ex. 7, with 1:2:3 mass ratio of 75:20:5, exhibits poorer capacity retention than Ex. 2, with ratio 70:20:10. Examiner respectfully submits that such does not prove criticality to the third mass range of 10–30 mass%. Rather, 1) such is one value within the broader range, and it is unclear that criticality extends across the range (see MPEP 716.02(d)). Although other examples test outside 10–30 wt% third particles (e.g., Ex. 9, with ratio 45:20:35, or Comp. Exs. 2 and 3, with ratios 0:100:0 and 100:0:0, respectively), such vary particle contents outside their respective ranges, making it unclear that the poorer performance is solely attributable to the third mass range of 10–30%.
Further, 2) even if the third mass range were considered critical, Examiner respectfully submits that such is only critical at certain values of the other variables much narrower than claim 1’s ranges. For example, taking Ex. 2 as one of the best performances, the 10% third particles only appear “critical” alongside first particles of 70 wt% and second particles of 20 wt%, whereas claim 1 allows 50–70 wt% first particles and 20–40 wt% second particles. Because unexpected results must be commensurate with the claimed scope (MPEP 716.02(d)), this argument is further unpersuasive.
Further assuming, arguendo, that the results were unexpected and superior, the results further 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
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/J.S.M./Examiner, Art Unit 1751
/JONATHAN G LEONG/Supervisory Patent Examiner, Art Unit 1751 8/17/2026
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