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 .
Priority
Acknowledgment is made of applicant’s claim for foreign priority under 35 U.S.C. 119 (a)-(d)
with a filing date of The certified copy of JP2020-213999 has been filed in the present
application, received on 06/21/2023.
Drawings
The drawings are objected to because the graph in figure 1 appears to be missing titles for the x-axis and the y-axis. Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. The figure or figure number of an amended drawing should not be labeled as “amended.” If a drawing figure is to be canceled, the appropriate figure must be removed from the replacement sheet, and where necessary, the remaining figures must be renumbered and appropriate changes made to the brief description of the several views of the drawings for consistency. Additional replacement sheets may be necessary to show the renumbering of the remaining figures. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
Claim Objections
Claim 2 is objected to because of the following informalities: the recitation “in all elements other than oxygen” is awkwardly worded/unclear. Appropriate correction is required.
Claim Rejections - 35 USC § 102
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 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.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claim(s) 1 and 8 – 9 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Watanabe (JP2013239267A – cited in 06/21/2023 IDS, Machine translation provided by applicant).
Regarding Claim 1, Watanabe discloses composite particles for a non-aqueous electrolyte secondary battery (Fig. 1, [0031 – 0032];[0041]).
In example 4, Watanabe explicitly discloses an embodiment of the composite particle in which the amorphous/low crystalline solid electrolyte matrix of the particle 2 is specifically Li7La3Zr2O12 (Refer to Example 4 in Table 1 and [0116]), which one with ordinary skill in the art would recognize to be a type of lithium zirconate.
In the instant specification, the lithium zirconate phase is described as a lithium zirconate containing Li, Zr, and O where the atomic ratio of O to Zr is, for example, 2.0 or greater and 6.0 or less ([0025]) . Additionally, the applicant teaches that the lithium zirconate phase can also include at least one selected from the group consisting of: Na, K, Ca, Mg, B, P, and La ([0027]).
Therefore, by disclosing an embodiment of the composite particle where the matrix is a lithium zirconate which appears to be within the scope of zirconates taught in the instant specification, Watanabe further discloses the claimed structure of a composite comprising a lithium zirconate phase {i.e. Li7La3Zr2O12 matrix which would be 2 in Fig. 1}.
Watanabe further discloses the composite particles comprising a silicon phase dispersed in the lithium zirconate phase, that is Watanabe explicitly discloses dispersing Si nanoparticles 1 in the solid electrolyte matrix of the composite particles (Fig. 1, [0038 – 0041];[0116]), and one with ordinary skill in the art would reasonably expect the nanoparticles to provide the claimed phase, because in the instant specification, the silicon phase is taught to be particulate/formed from silicon raw materials such as silicon nanoparticles ([0045 – 0048];[0059 – 0060]).
Regarding Claim 2, Watanabe discloses all limitations as set froth above. For example 4, Watanabe teaches preparing the Li7La3Zr2O12 solid electrolyte raw material so as to have a molar ratio of Li:La:Zr = 7.7:3:2 and further teaches forming the composite from a mass ratio of nanosilicon: oxide solid electrolyte of 1:1 ([0115 – 0116]).
Watanabe does not explicitly disclose the content proportion zirconium {i.e MZr} and the content proportion of lithium {i.e. MLi} with respect to all elements other than oxygen; however, one with ordinary skill in the art would recognize that such proportions could be determined based on the mass and molar ratios taught by Watanabe as well as the atomic weights of Li, La, and Zr. Specifically, based on the molar ratio of Li:La:Zr:O and the atomic weights of Li, {i.e. 6.94 g/mol}, La {138.91 g/mol}, Zr {i.e. 91.22 g/mol}, and O {i.e. 16 g/mol}, Watanabe suggests a solid electrolyte raw material having the following: a total weight excluding oxygen of 652.61 g; a total weight including oxygen of 844.61 g; and, excluding the weight of oxygen, a mass percent of Li and a mass percent of Zr of 8.19% and 27.96%, respectively. Assuming 1g of Si and 1 g of solid electrolyte {i.e. 1:1 mass ratio} and considering the fraction of the solid electrolyte raw material excluding oxygen {i.e. 652.61 g / 844.61 g}, the mass of non-oxygen elements making up the solid electrolyte raw material is 0.7728 g and the total mass of non-oxygen elements making up the composite is 1.7728 g. Therefore, based on the total mass of non-oxygen elements making up the composite and the mass fractions of Zr and Li in the solid electrolyte raw material excluding oxygen, in example 4 of Watanabe, a content proportion of zirconium {i.e. MZr} is ≈ 15.8 mass%, which is within the claimed 14.6 mass% or more and 54.6 mass% or less, and a content proportion of lithium {i.e. MLi} is 4.62 mass% (Claim 2).
Regarding Claim 8, Watanabe discloses all limitations as set forth above. By disclosing an embodiment in which the solid electrolyte matrix is Li7.7La3Zr2O12 ([0116]), Watanabe further discloses wherein the lithium zirconate phase contains lanthanum, which is within the claimed scope of at least one element selected from the group consisting of sodium, potassium, calcium, magnesium, boron, phosphorous, and lanthanum.
Regarding Claim 9, Watanabe discloses a non-aqueous electrolyte secondary battery ([0079];[0088]), comprising a positive electrode ([0089 – 0091]), a negative electrode ([0079 – 0083]), wherein the negative electrode includes the composite particles (Refer to rejection of claim 1 above and [0029]).
Claim(s) 4 – 5 and 6 – 7 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Watanabe (JP2013239267A), as applied to claim 1 above, and further as evidenced by Tahara (WO 2017199606A1, Machine translation provided) and Il’ina ("Morphology and transport properties of the solid electrolyte Li7La3Zr2O12 prepared by the solid-state and citrate–nitrate methods." Journal of Power Sources 201 (2012), pp. 169-173 – NPL provided).
Regarding Claims 4 –7, Watanabe discloses all limitations as set forth above. In Watanabe, the matrix is taught to be formed around the Si nanoparticles by a sol-gel method or mechano-chemical method where the heat treatment step is carried out at 200 – 800°C ([0064 – 0067];[0069];[0078]). The composite of example 4, which includes the Li7.7La3Zr2O12 matrix, was formed from being heat treated 800°C ([0115 – 0116]).
Watanabe does not explicitly disclose wherein the lithium zirconate phase contains at least one selected from the group consisting of Li6Zr2O7, Li2ZrO3, and Li5.52Zr2.62O8 (Claim 4) and, in an X-ray diffraction pattern of the composite particles obtained by X-ray diffraction measurement, a peak attributed to the lithium zirconate phase appears around 2θ = x°, and the x° is at least one selected from 18.6°, 26.5°, and 36.5° (Claim 5); however one with ordinary skill in the art would reasonably expect the composite of example 4 in Watanabe when measured by X-ray diffraction to provide at least one lithium zirconate within the claimed list and further at an angle within the claimed selection for the following reasons:
Tahara, directed toward composite particles including Si particles covered by conductive coating and a Li-containing oxide, teaches that crystal phases of Li-containing oxides are affected by heat treatment temperature, and that Li-containing oxides including metal oxides such as ZrO2, prepared from sol gel or mechano-chemical means, at heat treatment temperatures at 600°C or higher, provide mixed phase or single phases of amorphous or crystalline phase ZrO2 (monoclinic crystal, tetragonal), Li2ZrO3, Li6Zr2O7, Li8ZrO6 ([14];[16];[18]).
Il’ina, which is particularly directed to LLZO solid electrolytes, shows that Li7La3Zr2O12 synthesized at temperatures lower than 1200°C {i.e. particularly 900°C} and prior to sintering, possess a plurality of peaks corresponding to ZrO2 at 2θ including ≈ 31° (Refer to peaks labeled with +) and Li2ZrO3 at 2θ including ≈ 19° (Refer to peaks labeled with *) present within their XRD patterns (See Fig. 1(a) and first paragraph of 3.Results and Discussion section on pg. 170).
Therefore, because Watanabe teaches forming a Li7.7La3Zr2O12 matrix around the Si particles at a heat treatment temperature of 800°C ([0115 – 0116]), which is within the range of temperatures taught to be capable of providing the lithium-containing, zirconium oxide phases in Tahara, and further is a temperature relatively close to the synthesis temperature {i.e. 900°C} shown by Il’ina to result in impurity peaks including Li2ZrO3 at 2θ such as ≈ 19°, one with ordinary skill in the art would reasonably expect the example composite particle of Watanabe to provide, when measure by X-ray diffraction, at least a phase peak corresponding to Li2ZrO3 at around 2θ = 18.6, and thus within the claimed scope.
Watanabe further does not explicitly disclose wherein a ZrO2 phase is dispersed in the lithium zirconate phase (Claim 6) and, in an X-ray diffraction pattern of the composite particles obtained by X-ray diffraction measurement, a peak attributed ZrO2 phase appears around 2θ = 30.7° (Claim 7); however, one with ordinary skill in the art would reasonably expect the Li7.7La3Zr2O12 matrix in Watanabe to include a ZrO2 phase and further provide a peak attributed ZrO2 phase around 2θ = 30.7°, because, as established above, Watanabe teaches forming a Li7.7La3Zr2O12 matrix around the Si particles at a heat treatment temperature of 800°C ([0115 – 0116]), which is within the range of temperatures taught to be capable of providing the lithium-containing, zirconium oxide phases in Tahara, and further is a temperature relatively close to the synthesis temperature {i.e. 900°C} shown by Il’ina to result in phase peaks including ZrO2 at 2θ such as ≈ 31°.
Claim(s) 1 and 9 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Tahara (WO 2017199606A1)
Regarding Claim 1, Tahara discloses composite particles, that is Tahara teaches aggregate particles formed from a plurality of a Si particles that are covered by a Li-containing oxide and bonded by a conductive substance, which one with ordinary skill in the art would recognize to be a type of composite particle (Fig. 1; [08 – 11]), for a non-aqueous electrolyte secondary battery (Fig. 2; [09 – 11]).
Tahara teaches the composite particles being aggregate particles formed by aggregation of Li-containing oxide and Si particles having a conductive binder substance ([09]). As show in Fig. 1, the Li-containing oxide 30 covers the Si particles 20 of the composite particles. Tahara further teaches metal oxide of the matrix containing Li being one or more selected from SiO2, Al2O3, TiO2, and ZrO2 ([13]). In example 3, Tahara provides an embodiment of the composite particle using a Li-containing oxide that includes Zr as the metal of the metal oxide and further teaches that when the Li-containing oxide contains Zr, a Li-containing oxide coating of the mixed phase or single phase of
amorphous or crystalline phase ZrO2 (monoclinic crystal, tetragonal), Li2ZrO3, Li6Zr2O7, Li8ZrO6 is obtained (Table 1; [14];[44];[46]).
By teaching an embodiment of aggregate particles including Si particles coated by a lithium-containing oxide consisting of Zr, Tahara further discloses a composite particle structure within the claimed scope a composite particle comprising a lithium zirconate phase, and a silicon phase dispersed in the lithium zirconate phase. {Examiner Note: The composite particle structures in Tahara appears to read on the claimed structure of being “a silicon dispersed in the lithium zirconate phase”, because the Si particles in Tahara are explicitly disclosed to be of a Si crystal phase in [21] and the Si particles, by being completely surrounded by the lithium-containing oxide consisting of Zr, are necessarily dispersed within the composite particle maxtrix in a lithium-containing oxide consisting of Zr that provides lithium zirconate phases.
Regarding Claim 9, Tahara further discloses a non-aqueous electrolyte secondary battery (Fig. 2; [32]) comprising a positive electrode ([33 – 34]), a negative electrode ([29]), wherein the negative electrode includes the composite particles (Refer to rejection of claim 1 above and [27];[29]).
Claim(s) 4 – 5 and 6 – 7 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Tahara (WO 2017199606A1), as evidenced by Pfeiffer ("Reaction mechanisms and kinetics of the synthesis and decomposition of lithium metazirconate through solid-state reaction." Journal of the European Ceramic Society 24, no. 8, pp. 2433-2443 – NPL provided).
Regarding Claims 4 – 7, Tahara discloses all limitations as set forth above. In example 3, Tahara provides an embodiment of the composite particle using a Li-containing oxide that includes Zr as the metal of the metal oxide and further teaches that when the Li-containing oxide contains Zr, a Li-containing oxide coating of the mixed phase or single phase of amorphous or crystalline phase ZrO2 (monoclinic crystal, tetragonal), Li2ZrO3, Li6Zr2O7, Li8ZrO6 is obtained (Table 1; [14];[44];[46]). To form the Li-containing oxide on the Si particles the Si particles were added to a reactant solution containing the raw materials for the Li-containing oxide and calcined at 1000°C ([44];[46]).
Tahara does not particularly disclose, for the Zr-including embodiment of the composite particles, the lithium zirconate phase containing at least one selected from the group consisting of Li6Zr2O7, Li2ZrO3, and Li5.52Zr2.62O8 (Claim 4) and, in an X-ray diffraction pattern of the composite particles obtained by X-ray diffraction measurement, a peak attributed to the lithium zirconate phase appearing around 2θ = x°, and the x° being at least one selected from 18.6°, 26.5°, and 36.5° (Claim 5); however one with ordinary skill in the art would reasonably expect the composite of example 3 in Tahara when measured by X-ray diffraction to provide at least one lithium zirconate within the claimed list and further at an angle within the claimed selection, because Pfeiffer, directed toward lithium zirconates consisting of Li, Zr, and O, shows an XRD pattern for lithium zirconate formed by heat treating at 1000°C, and in the XRD pattern peaks corresponding to phases Li2Zr2O3 at 2θ ≈ 36° (Refer to peaks labeled with + in Fig. 2) and ZrO2 at 2θ ≈ 31° (Refer to peaks labeled with diamond in Fig. 2) are shown (Fig. 2; First paragraph in 1. Introduction section, pg. 2433; (Refer to first and second paragraph of 3. Results and Discussion section, pg. 2434 – 2435).
As such, since Tahara teaches forming a Li-containing Zr oxide coating at a heat treatment temperature of 1000°C ([44];[46]), and already suggests obtaining phases such as ZrO2 (monoclinic crystal, tetragonal), Li2ZrO3, Li6Zr2O7, and/or Li8ZrO6 ([14]), one with ordinary skill in the art would reasonably expect the example composite particle of Tahara to provide, when measured by X-ray diffraction, at least a peak corresponding to Li2ZrO3 at around 2θ = 36.5, and thus within the claimed scope since, as shown by Pfeiffer, heat treatment temperatures of 1000°C for lithium zirconates provide Li2ZrO3 as a phase and a peak corresponding to said phase at a 2θ of ≈ 36.
Tahara further does not explicitly disclose a ZrO2 phase dispersed in the lithium zirconate phase (Claim 6) and, in an X-ray diffraction pattern of the composite particles obtained by X-ray diffraction measurement, a peak attributed ZrO2 phase appearing around 2θ = 30.7° (Claim 7); however, one with ordinary skill in the art would reasonably expect the Li-containing Zr oxide coating of Tahara to include a ZrO2 phase and further provide a peak attributed ZrO2 phase appears around 2θ = 30.7°, because, as established above, Tahara already suggests obtaining phases such as ZrO2 (monoclinic crystal, tetragonal), Li2ZrO3, Li6Zr2O7, and/or Li8ZrO6 ([14]) and teaches forming the Li-containing Zr oxide coating at a heat treatment temperature of 1000°C ([44];[46]), which, as shown by Pfeiffer, is a synthesis temperature that provides a ZrO2 phase and a peak corresponding to said phase at a 2θ of ≈ 31°.
Claim Rejections - 35 USC § 103
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.
Claim(s) 3 is rejected under 35 U.S.C. 103 as being unpatentable over Watanabe (JP2013239267A) as applied to claim 1 above, and further below.
Regarding Claims 3, Watanabe discloses all limitations as set forth above. As established above, based on the total mass of non-oxygen elements making up the composite and the mass fractions of Zr and Li in the solid electrolyte raw material excluding oxygen, in example 4 of Watanabe, the content proportion of zirconium {i.e. MZr} is ≈ 15.8 mass% and the content proportion of lithium {i.e. MLi} is 4.62 mass%. As such, Watanabe exemplifies a ratio of the content proportion of MLi to the content proportion of MZr, calculated with the content proportion MZr taken as 100, of 29.
Therefore, Watanabe does not explicitly disclose an embodiment in which the ratio is 4.7 or greater and 23.2 or less.
However, generally, when utilizing a lithium lanthanum zirconate solid electrolyte, Watanabe teaches having the solid electrolyte represented by: Li7+xLa3Zr2O12+(x/2) where -5 ≤ x ≤ 3 ([0036]); thus, Watanabe suggests using lithium zirconates in which the molar proportion of the Li is smaller than what is exemplified in example 4. Furthermore, Watanabe teaches generally having the content of Si nanoparticles in the composite be preferably 5 mass% or more and 90 mass% or less for the purpose of achieving sufficient battery capacity {i.e. is increased by increasing the amount of Si nanoparticles} and effective suppression of the expansion/contraction of the Si nanoparticles {i.e. is decreased by increasing the amount of Si nanoparticles}. Watanabe further teaches that the ratio of oxide solid electrolyte matrix to Si is important for improving the initial capacity and cycle characteristics ([0142]).
One with ordinary skill in the art would appreciate/recognize that, in the composite of Watanabe, the content of Si and molar ratio of Li, would affect the ratio of the content proportion of MLi to the content proportion of MZr, and that because Watanabe teaches molar ratios which reduce the content Li in the lithium lanthanum zirconate, Watanabe necessarily also teaches/suggests compositions of composite particles that would provide MLi to MZr ratios overlapping/at least encompassing claimed range.
Selection of content proportion ratio within the overlapping portion of the ranges would have been prima facie obvious to one with ordinary skill in the art, before the effective filing date of the claimed invention, because such a selection would have a reasonable expectation of success in arriving at a lithium lanthanum zirconate solid electrolyte matrix with the conductivity and electrochemical durability desired by Watanabe ([0036]) [See MPEP 2144.05(I)].
Furthermore, selection of a ratio within the overlapping portion would have been further obvious to optimize the proportion of Si nanoparticles and solid electrolyte material in the composite {i.e. increasing battery capacity vs. achieving suppression of expansion/contraction of nanoparticles} while also ensuring that the lithium zirconate solid electrolyte is of a composition that provides the durability and conductivity desired by Watanabe, with a reasonable expectation of success and without undue experimentation [MPEP 2144.05(II)].
Claim(s) 2 – 3 are rejected under 35 U.S.C. 103 as being unpatentable over Tahara (WO 2017199606A1) as applied to claim 1 above, and further below.
Regarding Claims 2 – 3, Tahara discloses all limitations as set forth above. In example 3, the Li-containing oxide has a composition in which the molar ratio of Li and the metal element Zr, Zr/Li = 10 (Refer to Example 3 in Table 1).
Tahara does not explicitly disclose the composite particles having a content proportion MZr of zirconium with respect to all elements other than oxygen is 14.6 mass% or more and 54.6 mass% or less and a content proportion MLi of lithium with respect to all elements other than oxygen is 0.9 mass% or more and 10.4 mass% or less (Claim 2) or further wherein a ratio of MLi to MZr, calculated with MZr taken as 100, is 4.7 or greater and 23.3 or less (Claim 3).
Generally Tahara teaches controlling the molar ratio of the metal M to Li to be preferably 0.2 to 10 to prevent Li2O precipitates from causing defects, sufficiently ensure that contact between the active material and electrolytic solution is restricted and prevent increases in Li ion conduction resistance ([13]). When the metal is Zr, based on the molar masses of Li and Zr, the taught molar ratio provides a general mass ratio of Li/Zr of 6.94/912.2 ≈ 0.007 to 6.94/18.244 ≈ 38. As such, Tahara suggests Li-containing oxides with proportions of Zr as high as 99 wt% and as low as 73 wt%. The Li-containing oxide is further taught to be included in the composite in an amount of 0.5 – 10 mass% for the purpose of sufficiently preventing contact between the active material and electrolyte while also preventing increases in Li ion conduction resistance/deterioration in responsiveness of the electrode reaction ([12]). The content of the conductive binder is 10% mass – 50 mass% for the purpose of achieving suppression of the expansion/contraction of the Si particles while also preventing increases in resistance ([20]).
One with ordinary skill in the art would further reasonably appreciate/recognize, that since Tahara teaches using an amount of Si particles in the composite particles {i.e. 40 - 89.5 mass% based on taught ranges of conductive substance and Li-containing oxide that overlaps the amount taught to be included in the applicant’s composite particles (Instant Specification: [0049]) and further lithium zirconates that have a mass ratio of Li to Zr that encompasses the claimed ratio, Tahara appears to teach/suggests composite particles compositions that would provide overlapping/at least encompassing content proportions of MLi, the content proportions of MZr, and MLi / MZr ratios.
Selection of content proportions within the overlapping portion of the ranges and further content proportions that provide a ratio within the claimed range, would have been prima facie obvious to one with ordinary skill in the art, before the effective filing date of the claimed invention, because such a selection would have a reasonable expectation of success in arriving at a lithium coating capable of achieving the Li ion conductivity and stability desired by Tahara ([08]) [See MPEP 2144.05(I)].
One with ordinary skill in the art would further appreciate/recognize that, in the composite of Tahara, the amount of conductive binder, the amount of Li-containing oxide and molar ratio of Li and Zr in the Li-containing oxide, would affect the content proportion of MLi, the content proportion of MZr, and the ratio of the content proportion of MLi to MZr.
Therefore, selection of content proportions within the overlapping portion of the ranges and further content proportions that provide a ratio within the claimed range, would have been further obvious to optimize the molar ratios {i.e. Li/Zr} of the Li-containing oxide compositions {i.e. balance increases in resistances vs. formation of free Li2O precipitates}, the amount of lithium containing oxide in the composite {i.e. balance increases in resistance vs. sufficient particle coverage}, and the amount of conductive binder {i.e. balance increases in resistance vs. achieving sufficient expansion/contraction effect}, with a reasonable expectation of success and without undue experimentation [MPEP 2144.05(II)].
Claim(s) 1 – 3 and 8 – 9 are alternately rejected under 35 U.S.C. 103 as being unpatentable over Tahara (WO 2017199606A1) in view of Watanabe (JP2013239267A) {Examiner Note: Assuming, arguendo, that applicant is able to persuasively explain that the structure of the Si particles and Li-M containing oxide in Tahara does not read on the claimed structure of “a silicon phase dispersed in the lithium zirconate phase”, the following additional rejection is relied upon}.
Regarding Claim 1, Tahara discloses composite particles, that is Tahara teaches aggregate particles formed from a plurality of a Si particles that are covered by a Li-containing oxide and bonded by a conductive substance, which one with ordinary skill in the art would recognize to be a type of composite particle (Fig. 1; [08 – 11]), for a non-aqueous electrolyte secondary battery (Fig. 2; [09 – 11]).
Tahara teaches the composite particles being aggregate particles formed by aggregation of Li-containing oxide and Si particles having a conductive binder substance ([09]). As show in Fig. 1, the Li-containing oxide 30 covers the Si particles 20 of the composite particles. Tahara further teaches the Li-containing oxide being a matrix material containing Li and a metal oxide selected from SiO2, Al2O3, TiO2, and ZrO2 ([13]). In example 3, Tahara provides an embodiment of the composite particle using a Li-containing oxide that includes Zr as the metal of the metal oxide and further teaches that when the Li-containing oxide contains Zr, a Li-containing oxide coating of the mixed phase or single phase of
amorphous or crystalline phase ZrO2 (monoclinic crystal, tetragonal), Li2ZrO3, Li6Zr2O7, Li8ZrO6 is obtained (Table 1; [14];[44];[46]).
By teaching an embodiment of aggregate particles including Si particles coated by a lithium-containing oxide consisting of Zr, Tahara further discloses a composite particle comprising a lithium zirconate phase (Fig. 1, 30; [14];[44];[46];[59]) and a silicon phase (Fig. 1, 20; [21];[59]).
Tahara does not particularly disclose the silicon phase dispersed in the lithium zirconate phase.
Watanabe teaches composite particles for the negative electrode active material of a battery comprising Si nanoparticles 1 dispersed in a solid electrolyte matrix 2 (Fig. 1, [0038 – 0041];[0116]). The solid electrolyte that forms the matrix is taught to be Li ion conductive, oxide solid electrolytes that are amorphous/have low crystallinity and high ionic conductivity ([0032 – 0035]). Lithium zirconates are included among Watanabe’s taught solid electrolyte and the matrix suppresses the expansion and contraction of the individual Si nanoparticles, and therefore, the expansion and contraction of the entire negative electrode active material can be suppressed compared to when the Si nanoparticles are in contact with each other and form clumps ([0036];[0040]).
Therefore, it would have been obvious to one with ordinary skill in the art, before the effective filing date of the claimed invention, to form the composite particles of Tahara by dispersing the solid silicon particles in the Li-containing zirconate, and thus obtain the claimed composite particle structure, because, as shown by Watanabe, it is already known in the art to form composite negative electrode active material particles by dispersing Si particles in amorphous/low crystalline, conductive lithium zirconates, and such a modification would have a reasonable expectation of success, to provide the Li ion conductivity and particle stability {i.e. suppression of expansion/contraction of Si particles} effects desired by Tahara (Tahara: [08])
Regarding Claims 2 – 3, modified Tahara discloses all limitations as set forth above. In example 3, the Li-containing oxide has a composition in which the molar ratio of Li and the metal element Zr, Zr/Li = 10 (Refer to Example 3 in Table 1). In modified Tahara, as established above, it is the Li-containing oxide in which the Si particles are dispersed in (Watanabe: (Fig. 1, [0038 – 0041];[0116]).
Modified Tahara does not explicitly disclose the composite particles having a content proportion MZr of zirconium with respect to all elements other than oxygen is 14.6 mass% or more and 54.6 mass% or less and a content proportion MLi of lithium with respect to all elements other than oxygen is 0.9 mass% or more and 10.4 mass% or less (Claim 2) or further wherein a ratio of MLi to MZr, calculated with MZr taken as 100, is 4.7 or greater and 23.3 or less (Claim 3).
Generally Tahara teaches controlling the molar ratio of the metal M to Li to be preferably 0.2 to 10 to prevent Li2O precipitates from causing defects, sufficiently ensure that contact between the active material and electrolytic solution is restricted and prevent increases in Li ion conduction resistance ([13]). When the metal Zr, the taught molar ratio provides a general mass ratio of Li/Zr of 6.94/912.2 ≈ 0.007 to 6.94/18.244 ≈ 38. As such, Tahara suggests Li-containing oxides with proportions of Zr as high as 99 wt% and as low as 73 wt%. The Li-containing oxide is further taught to be included in the composite in an amount of 0.5 – 10 mass% for the purpose of sufficiently preventing contact between the active material and electrolyte while also preventing increases in Li ion conduction resistance/deterioration in responsiveness of the electrode reaction ([12]).
Watanabe further teaches generally having the content of Si nanoparticles in the composite be preferably 5 mass% or more and 90 mass% or less for the purpose of achieving sufficient battery capacity {i.e. is increased by increasing the amount of Si nanoparticles} and effective suppression of the expansion/contraction of the Si nanoparticles {i.e. is decreased by increasing the amount of Si nanoparticles}. Watanabe further teaches that the ratio of oxide solid electrolyte matrix to Si is important for improving the initial capacity and cycle characteristics ([0142]).
Since the composite particles of modified Tahara have a composition/structure like the particles in Watanabe {i.e. compose of lithium zirconate and Si particles dispersed in the lithium zirconate} and thus contain an amount of Si particles that overlaps the amount the amount taught to be included in the applicant’s composite particles (Watanabe: [0042]; Instant Specification: [0049]), and since Tahara teaches lithium zirconate compositions in which have mass ratio of Li/Zr that encompasses the claimed ratio, one with ordinary skill in the art would reasonably expect modified Tahara content proportions of MLi, content proportions of MZr, and MLi / MZr ratios to overlap/at least encompass the claimed content proportion ranges and ratio range.
Selection of content proportions ratio within the overlapping portion of ranges and further content proportions that provide a ratio within the claimed range, would have been prima facie obvious to one with ordinary skill in the art, before the effective filing date of the claimed invention, because such a selection would have a reasonable expectation of success in arriving at a lithium coating capable of achieving the Li ion conductivity and stability desired by Tahara ([08]) [See MPEP 2144.05(I)].
One with ordinary skill in the art would also appreciate/recognize that, in the composite of modified Tahara, the amount of Si particles, the amount of Li-containing oxide and molar ratio of Li and Zr in the Li-containing oxide, would affect the content proportion of MLi, the content proportion of MZr, and the ratio of the content proportion of MLi to MZr.
Therefore, selection of content proportions within the overlapping portion of the ranges and further content proportions that provide a ratio within the claimed range would have further been obvious, before the effective filing date of the claimed invention, to optimize the molar ratios {i.e. Li/Zr} of the Li-containing oxide compositions {i.e. balance increases in resistances vs. formation of free Li2O precipitates}, the amount of lithium containing oxide in the composite {i.e. balance increases in resistance vs. sufficient particle coverage}, and the amount of conductive binder {i.e. balance increases in resistance vs. achieving sufficient expansion/contraction effect}, with a reasonable expectation of success and without undue experimentation [MPEP 2144.05(II)].
Regarding Claim 8, modified Tahara discloses all limitations as set forth above. For the Li-containing oxide of composite particles, Tahara generally teaches using Li-containing oxides having stable and high Li-ion conductivity ([13]). Furthermore, Tahara teaches and exemplifies using Lithium zirconates (Refer to Table 1, Example 3 and [13 – 14]).
Modified Tahara does not explicitly disclose wherein the lithium zirconate phase contains at least one element selected from the group consisting of sodium, potassium, calcium, magnesium, boron, phosphorus, and lanthanum.
As established above, Lithium zirconates are included among Watanabe’s taught solid electrolyte ([0035 – 0036]). Watanabe further teaches a preference for using Li7+xLa3Zr2O12+(x/2) where -5 ≤ x ≤ 3 because of its high electrochemical durability ([0036]). The solid electrolytes in Watanabe are also taught to have high ionic conductivity ([0034]).
It would have been obvious to one with ordinary skill in the art, before the effective filing date of the claimed Invention, to have modified the lithium zirconate material of Tahara to include La, as taught by Watanabe, and thus obtain a lithium zirconate containing an element within the claimed list, with a reasonable expectation of success in obtaining a Li-containing oxide with the desired characteristic of high conductivity and further high electrochemical durability in the composite particles of Tahara.
Regarding Claim 9, Tahara discloses a non-aqueous electrolyte secondary battery (Fig. 2; [32]) comprising a positive electrode ([33 – 34]), a negative electrode ([29]), wherein the negative electrode includes the composite particles (Refer to rejection of claim 1 above and [27];[29]).
Claim(s) 4 – 5 and 6 – 7 are rejected under 35 U.S.C. 103 as being unpatentable over Tahara (WO 2017199606A1) and Watanabe (JP2013239267A), as applied to claim 1 above, and further as evidenced by Pfeiffer ("Reaction mechanisms and kinetics of the synthesis and decomposition of lithium metazirconate through solid-state reaction." Journal of the European Ceramic Society 24, no. 8, pp. 2433-2443).
Regarding Claims 4 – 7, modified Tahara discloses all limitations as set forth above. In example 3, Tahara provides an embodiment of the composite particle using a Li-containing oxide that includes Zr as the metal of the metal oxide and further teaches that when the Li-containing oxide contains Zr, a Li-containing oxide coating of the mixed phase or single phase of amorphous or crystalline phase ZrO2 (monoclinic crystal, tetragonal), Li2ZrO3, Li6Zr2O7, Li8ZrO6 is obtained (Table 1; [14];[44];[46]). To form the Li-containing oxide on the Si particles the Si particles were added to a reactant solution containing the raw materials for the Li-containing oxide and calcined at 1000°C ([44];[46]).
Tahara does not particularly disclose, for the Zr-including embodiment of the composite particles, the lithium zirconate phase containing at least one selected from the group consisting of Li6Zr2O7, Li2ZrO3, and Li5.52Zr2.62O8 (Claim 4) and, in an X-ray diffraction pattern of the composite particles obtained by X-ray diffraction measurement, a peak attributed to the lithium zirconate phase appearing around 2θ = x°, and the x° being at least one selected from 18.6°, 26.5°, and 36.5° (Claim 5); however one with ordinary skill in the art would reasonably expect the composite of example 3 in Tahara when measured by X-ray diffraction to provide at least one lithium zirconate within the claimed list and further at an angle within the claimed selection, because Pfeiffer, directed toward lithium zirconates consisting of Li, Zr, and O, shows an XRD pattern for lithium zirconate formed by heat treating at 1000°C, and in the XRD pattern peaks corresponding to phases Li2Zr2O3 at 2θ ≈ 36° (Refer to peaks labeled with + in Fig. 2) and ZrO2 at 2θ ≈ 31° (Refer to peaks labeled with diamond in Fig. 2) are shown (Fig. 2; First paragraph in 1. Introduction section, pg. 2433; (Refer to first and second paragraph of 3. Results and Discussion section, pg. 2434 – 2435).
As such, since Tahara teaches forming a Li-containing Zr oxide coating at a heat treatment temperature of 1000°C ([44];[46]), and already suggests obtaining phases such as ZrO2 (monoclinic crystal, tetragonal), Li2ZrO3, Li6Zr2O7, and/or Li8ZrO6 ([14]), one with ordinary skill in the art would reasonably expect the example composite particle of modified Tahara to provide, when measured by X-ray diffraction, at least a peak corresponding to Li2ZrO3 at around 2θ = 36.5, and thus within the claimed scope since, as shown by Pfeiffer, heat treatment temperatures of 1000°C for lithium zirconates provide Li2ZrO3 as a phase and a peak corresponding to said phase at a 2θ of ≈ 36.
Tahara further does not explicitly disclose a ZrO2 phase dispersed in the lithium zirconate phase (Claim 6) and, in an X-ray diffraction pattern of the composite particles obtained by X-ray diffraction measurement, a peak attributed ZrO2 phase appearing around 2θ = 30.7° (Claim 7); however, one with ordinary skill in the art would reasonably expect the Li-containing Zr oxide coating of modified Tahara to include a ZrO2 phase and further provide a peak attributed ZrO2 phase around 2θ = 30.7°, because, as established above, Tahara already suggests obtaining phases such as ZrO2 (monoclinic crystal, tetragonal), Li2ZrO3, Li6Zr2O7, and/or Li8ZrO6 ([14]) and teaches forming the Li-containing Zr oxide coating at a heat treatment temperature of 1000°C ([44];[46]), which, as shown by Pfeiffer, is a synthesis temperature that provides a ZrO2 phase and a peak corresponding to said phase at a 2θ ≈ 31°.
Conclusion
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/A.Y.O./Examiner, Art Unit 1751
/JONATHAN G LEONG/Supervisory Patent Examiner, Art Unit 1751 2/25/2026