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 .
Claims 1-14 are currently pending and have been considered below.
Priority
Acknowledgment is made of applicant’s claim for foreign priority under 35 U.S.C. 119 (a)-(d). The certified copy has been filed in parent Application No. KR 10-2022-0139140, filed on October 26, 2022.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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 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 1-2, 6-12 and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Song et al., “Comparing the Electrochemical Performance of LiFePO4/C Modified by Mg Doping and MgO Coating”, Journal of Nanomaterials, 2013, (hereinafter “Song”) in view of Beck et al. (US20110068295) and Zinck et al. (US20170047612).
Regarding Claims 1 and 14: Song discloses a lithium secondary battery with a positive electrode including a lithium iron phosphate-based active material, a negative electrode, a separator, and an electrolyte. Song further discloses lithium iron phosphate active material modified by Mg doping and MgO coating for use as positive electrode active material (Section 2.1, 2.3, Fig.1, Fig. 3, Fig. 4). Song further disclose that the lithium iron phosphate active material is characterized by X-ray diffraction analysis and exhibits a crystalline structure.
Song does not disclose that the lithium iron phosphate-based active material has an amorphous-content index (AI) of 0.28 or less.
Beck teaches high-purity crystalline ferric phosphate materials having a desirable characteristic for use in synthesizing nano-sized lithium iron phosphate cathode material. Beck further teaches that the iron phosphate dihydrate may contain a non-crystalline or amorphous phase (paragraph [0166]). And that the crystallinity of the iron phosphate affects the properties of the lithium iron phosphate (paragraph [0167]).
Before the effective filling date of the current invention, it would been obvious to modify the lithium iron phosphate-based active material of Song with Beck’s amorphous content values because the more amorphous or less crystalline is less desired for LFP cathode synthesis.
The prior art teaches that the amorphous content and the crystallinity are result-effective properties fir LFP cathode materials, selecting a low amorphous content value, including AI of 0.28 or less, would have been an obvious optimization of a known result-effective property.
Regarding Claim 2: Song discloses all limitations of claim 1 as set forth above. Song does not disclose an amorphous-content index of 0.20 to 0.27.
Beck teaches that the more amorphous or less crystalline material is less desired for LFP synthesis (paragraph [0169]).
Before the effective filling date of the current invention, it would been obvious to one having ordinary skill in the art to understand that reducing the amorphous content and increasing crystallinity as taught by Beck, was desirable for improving or maintaining the properties of the lithium iron phosphate cathode material. The claimed Ai value is a quantitative expression associated with the amorphous content of the lithium iron phosphate based active material, where a lower AI value corresponds to reduce the amorphous content and or increased crystalline character of the LFP active material.
Regarding Claim 3: Song discloses a lithium iron phosphate-based cathode materials for lithium secondary batteries and teaches the modification of lithium iron phosphate active materials to improve electrochemical performance, conductivity and capability. (Introduction) Song teaches LiFePO4/C cathode active material. This compound corresponds to the claimed lithium iron phosphate-based compounds represented by the Formula 1 when: a=0, x=0, y=0 and b=0. Song expressly teaches the limitation of claim 3.
Regarding Claim 4: Song discloses all limitations of claim 3 as set forth above. Song discloses a lithium iron phosphate cathode materials having a crystal structure and teaches the preparation of the modified lithium iron phosphate compositions. (Introduction, Experiment) Song teaches LiFePO4 which has a Li:Fe:P molar ratio of 1:1:1. When M is present in the formula 1, the claimed Li/(Fe+M) ratio reads on Li/Fe and Song has Li/Fe = 1.0 which falls in the claimed range of 1.0 to 1.1. (Section 2.1)
Regarding Claim 5: Song discloses all limitations of claim 3 as set forth above. Song teaches LiFePO4=based active material. Song does not teach a P/(Fe+M) with molar ratio of 1.01 to 1.04.
Beck teaches a ferric phosphate material useful for lithium iron phosphate cathode synthesis having a P:Fe molar ratio greater than 1, including the ranges from 1.001 to 1.05 and 1.01 to 1.05. (paragraph [0205])
Before the effective filling date of the current invention, it would been obvious to one having ordinary skill in the art to use a slightly phosphorus-rich iron phosphate in preparing the lithium iron phosphate-based active material of Song because Beck teaches such ratios for material used in the LFP cathode synthesis.
The claimed range of 1.01 to 1.04 overlaps the range taught by Beck.
Regarding Claim 6: Song discloses all limitations of claim 1 as set forth above. Song further discloses a lithium iron phosphate cathode material in which carbon is wrapped around the particles. Song teaches the preparation of LiFePO4/C material and further teaches Mg-doped and MgO coated LiFePO4 composite wherein the conductive carbon is associated with the actives material particles to improve the electrical conductivity and electrochemical performance (Section 3.1, Fig 3(b)). Song further teaches that the carbon component contributes to enhanced conductivity and improved electrochemical performance.
Song expressly teaches a lithium iron phosphate active material comprising a conductive coating layer as claimed.
Regarding Claim 7: Song discloses all limitations of claim 1 as set forth above. Song discloses the fabrication of lithium iron phosphate positive electrodes including lithium iron phosphate active material, conductive carbon, binder and aluminum current collector. Song further teaches the preparation of the cathode slurries and coating of the slurry into a current collector to form a positive electrode (Section 2.3).
Song does not disclose the loading amount range of 350 mg/25cm2 to 2000mg/25 cm2.
Zinck teaches a positive electrode/current collector containing LiFePO4 active material, conductive agent and binder where the loading is based on the mass of LiFePO4 active material per unit area. Zinck teaches a loading ranges including 20 to 90mg/cm2 and 20 to 180mg/cm2. (paragraph [0133]- [0134])
The claimed loading ranges of 350mg/25cm2 to 2000mg/25cm2 corresponds to 14 mg/cm2 to 80 mg/cm2. Zinck’s disclosed loading ranges that overlap the claimed range.
Before the effective filling date of the current invention, it would been obvious to one having ordinary skill in the art to select the loading with the overlapping range in order to obtain the desired balance between energy density, and rate performance.
Regarding Claim 8: Song discloses all limitations of claim 1 and 7 as set forth above. Song further discloses the preparation of cathode slurries, coating of the slurry, drying and assembly (Section 2.3).
Song does not disclose a porosity of 25% to 60%.
Zinck teaches that the LiFePO4 positive electrode structure have a porosity range including 25-30%, 20-30%, 20-50%, 33-37% and 30-50% (paragraphs [0133]- [0134]). These disclosed porosity ranges overlap the claimed range of 25 to 60 %.
Before the effective filling date of the current invention, it would been obvious to one having ordinary skill in the art to modify the positive electrode of Song to have the porosity within the range taught by Zinck because the electrode porosity is a known structural parameter in lithium-ion battery electrodes. The claimed range is obvious because Zinck teaches overlapping porosity ranges for battery electrode.
Regarding Claim 9: Song discloses all limitations of claim 1. Song teaches charge and discharge testing and demonstrates enhanced electrochemical characteristics for the modified cathode materials. Song further teaches that the Mg-doped LiFePO4/C sample exhibits a discharge capacity of about 163 mAh/g. Since the theoretical capacity of LiFePO4 is about 170 mAh/g, Song’s reported capacity is approximately 95.6% of the theoretical capacity which reads on the claimed range. (Abstract, Section 3.2, Fig. 4 and 6, Conclusion)
Song does not teach the exact condition of charge capacity after charging to 3.7V at 0.1 C.
Before the effective filling date of the current invention, it would been obvious to one having ordinary skill in the art to combine Song’s high capacity LiFePO4/C cathode material with Beck’s teaching to reduce the amorphous content to obtain a charge capacity between 93% to 100%. A person having ordinary skill in the art would have understood that the charge/discharge capacity and voltage are a conventional battery performance parameters used to evaluate the lithium iron phosphate-based electrodes.
Regarding Claim 10: Song discloses a method of manufacturing a lithium secondary battery comprising preparation of a lithium iron phosphate-based active material, fabrication of a positive electrode, assembly of battery components, placement of the electrode assembly into a battery case and electrolyte injection. Song further discloses X-ray diffraction characterization of lithium iron phosphate-based active material. (Section 2 & 3)
Beck teaches that the amorphous content of iron phosphate materials affects the resulting lithium iron phosphate and that more amorphous or less crystalline material is less desired for the LFP cathode synthesis (paragraph [0169]). Beck further teaches that amorphous ferric phosphate may be crystallized into crystalline ferric phosphate material by controlling process conditions such as pH and temperature (paragraph [0184]).
Song and Beck do not disclose the preparation of a sample comprising a lithium iron phosphate-based active material and MgO in a weight ratio of 70:30, determining an amorphous content index or selecting the active material based upon a predetermined AI range.
Before the effective filling date of the current invention, it would been obvious to one having ordinary skill in the art to include an XRD-based material selection step in the manufacturing process of Song in order to select lithium iron phosphate-based active material having reduced amorphous content/increased crystallinity and taught by Beck, before manufacturing the positive electrode and battery.
Regarding Claim 11: Song discloses the limitations of claim 10 as set forth above.
Song does not disclose selecting a lithium iron phosphate-based active material having an amorphous-content index of 0.28 or less.
However, as discussed above with respect to claim 1 and 10, the claimed AI value is a quantitative expression of low amorphous content, selecting an AI of 0.28 or less would been an obvious optimization of a known result-effective property.
Regarding Claim 12: Song discloses the limitations of claim 10 as set forth above.
Song does not disclose selecting a lithium iron phosphate-based active material having an amorphous-content index of 0.20 or 0.27.
However, as discussed above with respect to the claims 1, 10 and 11, the claimed AI value is a quantitative expression of low amorphous content, selecting an AI of 0.20 to 0.27 would been an obvious to select a narrower optimized low-amorphous content range through a routine experimentation in view of Beck’s teaches that more amorphous or less crystalline material is less desired for LFP cathode synthesis.
Regarding Claim 13: Song discloses all limitations of claim 3 as set forth above. Song discloses a LiFePO4/C cathode material in which carbon is wrapped around the particles. Song teaches that the conductive carbon coatings improve conductivity and electrochemical performance of the lithium iron phosphate cathode materials. Song further discloses Mg-doped LiFePO4/C and MgO-coated LiFePO4/C materials containing conductive carbon associated with the lithium iron phosphate particles. (Introduction, Section 3.1, Fig. 3(b))
Accordingly, Song expressly teaches a lithium iron phosphate compound provided with a conductive coating layer.
Conclusion
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/NMRO/Examiner, Art Unit 1725
/NICOLE M. BUIE-HATCHER/Supervisory Patent Examiner, Art Unit 1725
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