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 .
Claim Rejections - 35 USC § 103
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-11 are rejected under 35 U.S.C. 103 as being unpatentable over Kitano et al. (US-20210167374, published 3 Jun 2021) in view of Min et al. (J. Electrochem. Soc. 2018, 165 (2), A79-A85).
In regard to claim 1, Kitano et al. teaches a method for forming a positive electrode active material comprising (i) providing a metal composite comprising nickel, cobalt, and manganese [0041], (ii) mixing and heating the metal composite with a lithium source to form a heat-treated product (a composite oxide of lithium, nickel, cobalt, and manganese) [0053] & [0059], (iii) dispersing the heat-treated products into particles [0061], (iv) washing with an alkali liquid medium and at least partially drying the particles to form a lithium-transition metal composite [0064]-[0065], (v) mixing the lithium-transition metal composite particles with a boron source [0070]-[0071], and (vi) heating the mix of particles and a boron source to yield a boron-modified LiNiCoMnO2 active material [0079]. Kitano et al. further teach that the formed lithium-transition metal composite may have a layered structure [0029]. Kitano et al. teaches that the adherence of boron to the composite particle surfaces results in increased discharge capacity in a battery (Table 2). Kitano et al. does not teach prior to washing or boron adhesion a step of contacting first particles (composite oxide comprising lithium and nickel) with a cobalt compound and a step of heat-treating a cobalt-adhering material between 500-900°C.
However, Min et al. teaches surface modification of a LiNi0.91Co0.06Mn0.03O2 cathode active material with Co3O4 to form a protective material coating which also enhances electrochemical performance (Abstract). The method comprises the steps of providing LiNi0.91Co0.06Mn0.03O2 particles, mixing together the composite particles and a stochiometric amount of Co3O4 in a mixer, and heating the Co3O4-coated composite particles at 720°C for 5 hours (pp. A80, left col., lines 47-48). In a comparison against other transition metal surface modifiers, cobalt was found to significant out-perform as a surface coating, by effectively removing free lithium and increasing electrochemical efficiency of the LiNi0.91Co0.06Mn0.03O2 composite material (pp. A81, Table I), with specific improvements in coulomb efficiency, capacity at 1 C, and capacity retention after 50 cycles.
Both Kitano et al. and Min et al. are drawn to electrochemical improvements of nickel-rich lithium/nickel/cobalt/manganese oxides. Kitano et al. discusses how nickel, the predominant non-Li cation in the disclosed composite material, disorder contributes to poor initial efficiency [0036]. While Kitano et al. addresses such cation disorder in the initial material, the addition of a partial boron coating as disclosed does not address cation disorder or dissolution over time at the electrolyte-electrode surface. Min et al. teaches that Co3O4 addresses cation disordering, phase transformation of residual Li, and degradation at the electrolyte-electrode surface during battery operation (pp. A79, left col.; pp. A81, left col., line 45 – right col., line 19). Overall, the boron coating described by Kitano et al. and the cobalt coating of Min et al. are both conductive materials which are designed to improve different aspects of battery performance.
With regard to the order of the steps, it would have been obvious to a person of ordinary skill to conduct the cobalt-adhesion of Min et al. and the boron adhesion of Kitano et al. separately on account of the vastly different temperature requirements of the disclose heat treatments. Furthermore, it would have been obvious, on account of the different temperature requirements, to first conduct the cobalt adhesion steps of Min et al. and second conduct the boron adhesion of Kitano et al., as the high temperature of the cobalt-adhering step (720°C) would be understood to be incompatible with the surface-deposited boron, which is adhered to the particle surface at a low temperature (100-450°C). While Min et al. demonstrates that the surface modification using an optimal loading of Co3O4 does reduce the amount of residual Li in the composite, it does not remove all residual Li (~40-70%, pp. A81, Table I). Therefore, to effectively form the electrochemically active Co-Li phase described by Min et al., but further remove residual Li which contributes to impedances on the material’s surface, a person of ordinary skill in the art would maintain the washing step of Kitano et al. which aims to dislodge unreacted/residual Li [0064].
Therefore, it would have been obvious to one of ordinary skill in the art at the relevant time to modify the process of Kitano et al. (i.e. providing particles, contacting particles with a liquid medium, contacting treated particles with boron) to include adhering cobalt to the particle surface and a heat treatment at 720°C (i.e. contacting particles with a cobalt compound, heat-treating the cobalt adhering material at 500-990°C), yielding the method as instantly claimed in claim 1, in order to obtain an electrode active material with superior capacity and longevity.
In regard to claim 2, Kitano et al. teaches heat-treated the boron adhering material (i.e. the boron mixture) at temperatures between 100-450°C [0079].
In regard to claim 3, Min et al. teaches contacting cobalt oxide (Co3O4) with the first particles (LiNi0.91Co0.06Mn0.03O2, pp. A80, left col., lines 37-48). In combining the processes of Min et al. and Kitano et al., a person of ordinary skill in the art, without an external motivation, would have no reason to deviate from the cobalt source presented in Min et al. and thus would employ cobalt oxide, as instantly claimed, in the combined teachings of Min et al. and Kitano et al.
In regard to claim 4, Min et al. teaches a 1 wt%, 2 wt%, and 7 wt% loading of Co3O4 on the surface of the LiNi0.91Co0.06Mn0.03O2 composite particles (pp. A81, left col., lines 37-40). After conversion to mols of cobalt atoms in Co3O4 and moles of metal atoms other than Li in LiNi0.91Co0.06Mn0.03O2, the taught loading of Co3O4 are equal to 1.2 mole% Co, 2.4 mole% Co, and 9.0 mole% Co. It would have been obvious to one of ordinary skill in the art to select the 1 wt% (1.2 mole%) or 2 wt% (2.4 mole%) Co3O4 loadings, which are within the instantly claimed range, based on the teachings of Min et al. which state as the surface coating loading increases beyond 2 wt%, there is significant drop-off in initial capacity and other properties (see charge capacity, discharge capacity, coulomb efficiency, and 1C capacity in Table I). Therefore, it would have been obvious to one of ordinary skill in the art at the relevant time, in combining the teachings of Kitano et al. and Min et al., to select a ratio of surface-adhered cobalt to non-Li metal atoms between 0.1-5 mole%.
In regard to claim 5, Kitano et al. teaches that the liquid medium used in the washing step may contain at least water [0065].
In regard to claim 6, Kitano et al. teaches that the liquid medium employed in the washing step may comprise alkali salts of lithium or sodium as instantly claimed [0065].
In regard to claim 7, Kitano et al. teaches that the boron compound used a boron source may be orthoboric acid, lithium tetraborate, ammonium pentaborate, lithium metaborate, or boron oxide [0072].
In regard to claim 8, Kitano et al. teaches that in contacting the boron compound and particles of the lithium transition metal oxide, the two components are added such that a ratio of moles of boron atoms in the boron compound and moles of metal atoms other than Li in the lithium-transition metal composite may be between 0.1-0.3 mole%. Kitano et al. explicitly states that the addition of boron as a surface dopant is related to, and increases, initial discharge capacity [0070] and thus is a results-effective variable with respect to the electrochemical properties of the final material, and one of ordinary skill in the art would be motivated to optimize the loading amount. With respect to the encompassing and overlapping ranges previously discussed, the subject matter as a whole would have been obvious to one of ordinary skill in the art at the time of invention to select the portion of the prior art’s range which is within the range of the applicants’ claims because it has been held prima facie case of obviousness to select a value in a known range by optimization for the results. In re Aller, 105 USPQ 233. Additionally, the subject matter as a whole would have been obvious to one of ordinary skill in the art at the time invention was made to have selected the overlapping portion of the range disclosed by the reference because overlapping ranges have been held to be a prima facie case of obviousness. In re Malagari, 182 USPQ.
In regard to claim 9, Kitano et al. teaches optimally the lithium transition metal composite oxide has the chemical formula LipNixCoyMnzM1wO2, wherein 0.8<x<1, and x+y+z+w≤1 [0034]-[0035]. Therefore, Kitano et al. teaches preferably a ratio of moles of Ni to total moles of Ni, Co, Mn, and M1 is between 0.8 and 1, which is within the instantly claimed range of 0.6≤x<1.
In regard to claim 10, Kitano et al. teaches the lithium transition metal composite oxide comprises at least manganese in formula (1) (see above). Preferably, in formula (1), 0.01≤z≤0.18 [0034]-[0035]. Therefore, Kitano et al. teaches preferably a ratio of moles of Mn to total moles of Ni, Co, Mn, and M1 is between 0≤z≤0.2, which overlaps the instantly claimed range of 0.02≤x<1. Kitano et al. suggests that the ratio of manganese to other metals in the composite has in impact on electric discharge capacity ([0030], lines 1-5), which would incentivize a person of ordinary skill in the art to optimize the manganese in the lithium transition metal composite oxide. The subject matter as a whole would have been obvious to one of ordinary skill in the art at the time invention was made to have selected the overlapping portion of the range disclosed by the reference because overlapping ranges have been held to be a prima facie case of obviousness. In re Malagari, 182 USPQ.
In regard to claim 11, Kitano et al. teaches that the lithium transition metal composite oxide has a composition represented by the following formula:
LipNixCoyMnzM1wO2 [0034]
Which maps to the instantly claimed formula:
LiqNirCosM1tM2uO2+α
As M1 as instantly claimed may be Mn (see claim 11, line 8).
Kitano et al. discloses the following in [0035]:
That Li has a range of 1.01≤p≤1.1, which is within the equivalent claimed range of 1.0≤q≤1.3.
That Ni has a range of 0.82≤x≤0.92, which overlaps the equivalent claimed range of 0.9≤r≤0.96.
That Co has a range of 0.03≤y≤0.18, which is within the equivalent claimed range of 0.01≤s≤0.05.
That Mn has a range of 0.01≤z≤0.18, which overlaps the equivalent claimed range of 0.02≤t≤0.08.
That M1 has a range of 0.005≤w≤0.05, which overlaps the equivalent (i.e. M2) claimed range of 0≤u≤0.02.
That x+y+z+w≤1, which overlaps the equivalent expression of r+s+t+u = 1.
That α = 0, which is within the claimed range of -0.1≤α≤0.1 (see oxygen in taught formula).
That M1, equivalent to instantly claimed M2, may be Ca, Zr, etc. [0032] & [0035]
With regard to the overlapping and encompassing ranges of ratios between Ni, Co, Mn, and other constituents of the composite, the subject matter as a whole would have been obvious to one of ordinary skill in the art at the time of invention to select the portion of the prior art’s range which is within the range of the applicants’ claims because it has been held prima facie case of obviousness to select a value in a known range by optimization for the results. In re Aller, 105 USPQ 233. Kitano et al. teaches that the ratio of Mn to other non-Li components has an effect on the material’s electrochemical properties, and thus would be the subject of optimization [0030]. Determining the best ratio of other components, with respect to an ideal amount of Mn in the composite, would have been a matter of ordinary skill in the art. Additionally, the subject matter as a whole would have been obvious to one of ordinary skill in the art at the time invention was made to have selected the overlapping portion of the range disclosed by the reference because overlapping ranges have been held to be a prima facie case of obviousness. In re Malagari, 182 USPQ.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
Mo et al. (Chemical Engineering Journal 2020, 400, 125820) which discloses lithium boron oxide doping of LiNi0.8Co0.1Mn0.1O2.
Wu et al. (J. Electrochem. Soc. 2020, 167, 130516) which discloses a dry-process surface coating of LiNi0.8Co0.1Mn0.1O2.
Li et al. (Journal of Alloys and Compounds 2019, 783, pp. 349-356) which discloses wet-process surface modification of Li[Li0.2Mn0.534Ni0.133Co0.133]O2 with Co3O4.
Yan et al. (Electrochimica Acta 2017, 249, pp. 179-188) which discloses wet-process surface doping of LiNi0.8Co0.15Al0.05O2 with cobalt nitrate.
JP-2018014208A, which discloses a wet-process surface modification of lithium-nickel oxides with cobalt hydroxide.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to MORDECAI M LEAVITT whose telephone number is (571)272-6637. The examiner can normally be reached Monday-Friday 8AM-5PM.
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/MORDECAI M LEAVITT/Examiner, Art Unit 1742
/MONICA A HUSON/Primary Examiner, Art Unit 1742
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