DETAILED ACTION
Introductory Notes
Any paragraph citation of the instant is in reference to the U.S. published patent application.
Claim Rejections - 35 USC § 102
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1-7, 10-11, and 13-15 are rejected under 35 U.S.C. 102(a)(2) as being anticipated by TOYAMA (US 20220115656 A1).
Regarding claim 1, TOYAMA discloses a positive electrode active material (“a positive electrode active material” [0001]) including a lithium composite oxide comprising at least nickel, cobalt, and a doping metal (claim 1, formula 1 which is a “lithium transition metal complex oxide” and includes nickel, cobalt, and X which “represents at least one metallic element” reading on doping metal) having a layered structure capable of intercalation/deintercalation of lithium (“lithium ions are intercalated between these layers and occupy lithium sites, and, during discharge, the lithium ions are deintercalated” [0029]),
the lithium composite oxide includes secondary particles, which are aggregates in which a plurality of primary particles are aggregated and a grain boundary is formed between adjacent primary particles (as depicted in Fig. 3(a) as well as “secondary particles formed by aggregation of a plurality of primary particles” [0014]),
and the secondary particles comprise primary particles exhibiting a concentration gradient in which the concentration of the doping metal has a negative slope from the grain boundary between the primary particles toward the center portion of the primary particle (“an atomic concentration D1 of X at a depth of 1 nm from an interface between the primary particles and an atomic concentration D2 of X at a central part of the primary particle satisfy D1>D2” [0014]),
wherein a first concentration gradient section having a negative slope and a second concentration gradient section having a positive slope are present in the concentration of the doping metal from a surface portion of the secondary particles toward a center portion of the secondary particles (as depicted in Figs 3(a) and 3(b) as well as Fig. 5 and discussed in at least paragraph [0014] referenced previously, the secondary particle is an aggregation of primary particles and each primary particle has a gradient decreasing from surface to center and then increasing from center to surface as a conceptual line is drawn through the primary particle; therefore the secondary particle will have multiple decreasing and increasing slopes when considering a path from secondary particle surface to secondary particle center because such a path consists of multiple primary particles),
and wherein when the radius of the secondary particles is R, the first concentration gradient section and the second concentration gradient section are limited to being present within a depth of 0 to 0.2R from the surface portion of the secondary particles.
The claim is being interpreted such that the first and second gradients, notably not ALL gradients, are limited to the depth given. Support for this interpretation can be found in paragraphs [0088-0092] of the instant which includes statements such as “repeatedly present at least twice or more from the surface portion of the secondary particle toward the center portion of the secondary particle” [0091] that indicate repetition with only the first two gradients being limited to 0.2R as discussed in [0092].
TOTAMA discloses “average particle diameter of the primary particles in the positive electrode active material is preferably 0.05 μm or more and 2 μm or less … and still more preferably 1.0 μm or less” [0048] as well as “the average particle diameter of the secondary particles in the positive electrode active material is, for example, preferably 3 μm or more and 50 μm or less” [0048]. Therefore, TOYAMA discloses a wide range of combinations of primary and secondary particles in which there is an entirety of a primary particle within a depth of 0.2R of the secondary particle. As such, the first and second gradient sections are present within 0.2R. Furthermore Example 1 in [0140-0141] provides average primary particle diameter of “less than 0.2 μm” [0140] and “a granulated substance having an average particle diameter of 3 μm or more and 50 μm or less” [0141] and therefore there are examples of secondary particles with at least a primary particle within 0.2R.
Regarding claim 2, TOYAMA discloses the primary particles are represented by the following Chemical Formula 1 (claim 1, formula 1 reads on instant chemical formula 1 including limitations toward the amounts of each component, as shown in the comparison below; furthermore TOYAMA discloses example 5 where “the mole fractions of the raw materials (Li:Ni:Co:Mn:Ti) reached 1.03:0.90:0.03:0.05:0.02” [0145]).
Instant
TOYAMA
PNG
media_image1.png
530
1093
media_image1.png
Greyscale
PNG
media_image2.png
383
1122
media_image2.png
Greyscale
Regarding claim 3, TOYAMA discloses concentrations (mol%) of Ni, Co, M1, M2 and M3 in the primary particles represented by Chemical Formula 1 satisfy Equation 2 (“Co proportion is set to 6% or less” [0016]; furthermore TOYAMA discloses example 5 where “the mole fractions of the raw materials (Li:Ni:Co:Mn:Ti) reached 1.03:0.90:0.03:0.05:0.02” [0145] providing an example with Co ratio of 3).
Regarding claim 4, TOYAMA discloses the secondary particles comprise the primary particles exhibiting a concentration gradient in which at least one concentration selected from M2 and M3 decreases from the grain boundary between the primary particles toward the center portion of the primary particles (“an atomic concentration D1 of X at a depth of 1 nm from an interface between the primary particles and an atomic concentration D2 of X at a central part of the primary particle satisfy D1>D2” [0014] wherein X reads on at least one of M2 and M3).
Regarding claim 6, TOYAMA discloses the first concentration gradient section and the second concentration gradient section are repeatedly present at least twice within a depth of 0 to 0.2R from the surface portion of the secondary particles.
As depicted in Figs 3(a) and 3(b) as well as Fig. 5 and discussed in at least paragraph [0014] referenced previously, the secondary particle is an aggregation of primary particles and each primary particle has a gradient decreasing from surface to center and then increasing from center to surface as a conceptual line is drawn through the primary particle; therefore the secondary particle will have multiple decreasing and increasing slopes when considering a path from secondary particle surface to secondary particle center because such a path consists of multiple primary particles.
TOTAMA discloses “average particle diameter of the primary particles in the positive electrode active material is preferably 0.05 μm or more and 2 μm or less … and still more preferably 1.0 μm or less” [0048] as well as “the average particle diameter of the secondary particles in the positive electrode active material is, for example, preferably 3 μm or more and 50 μm or less” [0048]. Therefore, TOYAMA discloses a wide range of combinations of primary and secondary particles in which there are two primary particles within a depth of 0.2R of the secondary particle. As such, the first and second gradient sections are repeatedly present at least twice. Furthermore Example 1 in [0140-0141] provides average primary particle diameter of “less than 0.2 μm” [0140] and “a granulated substance having an average particle diameter of 3 μm or more and 50 μm or less” [0141] and therefore there are examples of secondary particles with at least two primary particles and therefore two reptations within 0.2R.
Regarding claim 7, TOYAMA discloses a concentration maintenance section in which the absolute value of concentration change amount of the doping metal is less than 2 at% is present between the first concentration gradient section and the second concentration gradient section (as shown in Fig. 5 where outside the concentration changes at the interface, the concentrations are maintained and as shown in the table of Fig. 5 the Ti is below 2 at%).
Regarding claim 10, TOYAMA discloses the primary particle has an average particle diameter of 0.1 µm to 10.0 µm (“0.05 μm or more and 2 μm or less” [0048]).
Regarding claim 11, TOYAMA discloses when the average particle diameter of the primary particle is r, the concentration gradient in the primary particle is present within a depth of 0 to 0.2r from the grain boundary between the adjacent primary particles (as shown in Fig. 5 the gradient is present within 5 nm or less of the interface where 5nm is less than the claimed 20% of the primary particle diameter of “0.05 μm or more and 2 μm or less” [0048]).
Regarding claims 14 and 15, TOYAMA discloses a positive electrode including the positive electrode active material of claim 1; and a lithium secondary battery using the positive electrode of claim 14 (Claim 8 states “A lithium ion secondary battery comprising: a positive electrode containing the positive electrode active material for lithium ion secondary battery according to claim 1”).
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 12 is rejected under 35 U.S.C. 103 as being unpatentable over TOYAMA.
Regarding claim 12, TOYAMA discloses the secondary particles have an average particle diameter of 3 µm to 20 µm (“3 μm or more and 50 μm or less” [0048]) and it would have been obvious to one of ordinary skill in the art at the time of filing to select a portion of the disclosed range because selection of overlapping portion of ranges has been held to be a prima facie case of obviousness, see MPEP § 2144.05 (I)).
Claims 8 and 9 are rejected under 35 U.S.C. 103 as being unpatentable over TOYAMA in view of CHOI (US 20200062613 A1).
Regarding claims 8 and 9, TOYAMA discloses that the “positive electrode active material according to the present embodiment may contain … different components that coat the particles of the lithium transition metal complex oxide, for example, boron components, phosphorus components, sulfur components, fluorine components, organic substances, or the like” [0026]. However, TOYAMA does not expressly teach Chemical Formula 2 of claim 8.
CHOI is directed to a lithium composite oxide comprising secondary particles that are aggregates of primary particles; Ni and Co, as well as Al or Mn; and a dopant with a concentration gradient like TOYAMA.
CHOI discloses “a lithium alloy oxide existing at least a part of a) the interface between primary particles and b) the surface of secondary particles” [0060] as well as “the lithium alloy oxide may be used to entirely or partially coat the interface between the primary particles forming the lithium composite oxide and the surface of the secondary particle” [0062]. CHOI discloses “the lithium alloy oxide may be represented by Formula 2 below. LieM3fOg (wherein, M3 is at least one selected from Ti, Zr, Mg, V, B, Mo, Zn, Nb, Ba, Ca, Ta, Fe, Cr, Sn, Hf, Ce, W, Nd and Gd, 0≤e≤6, 0≤f≤6, and 0≤g≤10)” [0065-0066]. Notably Formula 2 of CHOI full reads on instant Chemical Formula 2. Furthermore, CHOI Formula 2 specifically lists B, V, Zr, Ba, and Ti which are all four possible elements of claim 9.
CHOI teaches the benefits of “thereby increasing structural stability, and when the positive electrode active material is used in a lithium secondary battery, high-temperature storage stability and lifespan characteristics of the positive electrode active material may be improved” [0063]. CHOI further teaches “the lithium alloy oxide may serve as a diffusion path of lithium ions in the positive electrode active material, and thus affect the improvement of the efficiency of the lithium secondary battery” [0063].
Before the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to coat the particles of TOYAMA with the lithium alloy oxide of CHOI in order to increase structural stability, high-temperature storage stability, and lifespan.
Therefore, modified TOYAMA discloses a compound represented by Chemical Formula 2 is present on at least a portion of the grain boundary between the adjacent primary particles and/or at least a portion of a surface of the secondary particles (as taught by CHOI).
Furthermore, modified TOYAMA discloses at least one compound selected from the list presented in claim 9 are present on at least a portion of the grain boundary between the adjacent primary particles and/or at least a portion of a surface of the secondary particle (as rendered obvious by Formula 2 of CHOI).
Response to Arguments
Regarding art-based rejections, applicant’s arguments with respect to the claims have been considered but are not persuasive. On page 8 in paragraph 3 of the remarks applicant states “TOYAMA teaches that the first and second concentration gradient sections are repeatedly present even in a region exceeding a depth of 0.2R” then continues the thrust of this argument through page 9. Examiner agrees with the premise that the gradient repeats in TOYAMA, however examiner disagrees with arguments that this precludes TOYAMA from reading on the claims and further notes such repetition is present in the instant specification. Instant [0090] states "the peak region may be present not only in a position adjacent to the surface of the secondary particle, but also in a position adjacent to the center portion of the secondary particle or a center portion of the secondary particle" (emphasis added) and furthermore [0091] states "repeatedly present at least twice or more from the surface portion of the secondary particle toward the center portion of the secondary particle, and the upper limit of the number of times the first and second concentration gradient sections s1 and s2 are repeated can be appropriately adjusted in consideration of the composition of the positive electrode active material and the type of doping metal" (emphasis added), the instant notably does not state a gradient is present ONLY twice. Notably claim 1 places a depth limit on the first two gradients, not all gradients.
Conclusion
The prior art made of record and not relied upon considered pertinent to applicant's disclosure (previously cited):
PARK (US 20160049647 A1) directed to a primary particle formed of a plurality of metals including a first metal and a secondary particle formed of at least one of the primary particle where the primary particle has a concentration gradient.
LEE (US 20170155146 A1) directed to a secondary particle including primary particles of a lithium composite metal oxide that contains nickel, cobalt, and manganese; and the primary particle is doped with one or two or more dopant elements selected from the group consisting of Nb, Sn, Mo, and Ta, the dopant element content being higher in a surface region of the primary particle than in the interior of the primary particle
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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to TRAVIS L MARTIN whose telephone number is (703)756-5449. The examiner can normally be reached M-F, 7am-4pm CT.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Allison Bourke can be reached on (303)297-4684. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/T.L.M./Examiner, Art Unit 1721
/ALLISON BOURKE/Supervisory Patent Examiner, Art Unit 1721