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). The certified copy has been filed in parent Application No. JP 2020189420, filed on November 13th, 2020.
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Claim Objections
Claim 7 is objected to because of the following informalities: The instant claim recites “a co-ball mile”. The Examiner believes this should recite “a co-ball mill.” Appropriate correction is required.
Claim Rejections - 35 USC § 112(b)
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 11 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Regarding claim 11, the instant claim recites “the crystalline sulfide solid electrolyte contains a thio-LISICON Region II-type crystal structure,” which is indefinite considering that the meaning and scope of the term is not remedied by the definition provided in the instant disclosure, which appears as follows:
“Here, the thio-LISICON Region II-type crystal structure" expresses any one of an Li4-xGePxS4-based thio-LISICON Region II-type crystal structure and a crystal structure similar to Li4-xGePxS4-based thio-LISICON Region II-type crystal structure” (Paragraph 0154)
It remains unclear the metes and bounds of what constitutes a Li4-xGePxS4-based thio-LISICON Region II-type crystal structure and how to determine the degree of similarity between the thio-LISICON region II-type crystal as claimed to a Li4-xGePxS4-based thio-LISICON Region II-type crystal structure according to the definition provided in the instant disclosure. Additionally, it is further unclear what limitations a Region II-type imparts to the overall crystal structure. The disclosure does not remedy this indefiniteness. Appropriate clarification 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.
Claims 1-2, 5-8, 12-14 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Takeshi (Japanese Patent Publication No. 2014096391 A).
Regarding claim 1, Takeshi teaches a method of producing a crystalline sulfide solid electrolyte (Paragraph 0013).
Takeshi discloses a method of producing a solid electrolyte including a first synthesis step and a second crystallization step (Paragraph 0013).
Takeshi teaches the first synthesis step may be performed according to a variety of methods (1) to (4) (Paragraph 0022).
In the first synthesis step of method (1), Takeshi teaches contacting lithium sulfide with one or more compounds including phosphorus sulfide and boron sulfide (Paragraphs 0013-0015). Takeshi teaches in the method to form the electrolyte, it is preferable to mix lithium sulfide with the other sulfides in an organic solvent which may be supplemented by additional solvent, including tetrahydrofuran and ethyl acetate (Paragraphs 0017 and 0020). Takeshi further teaches it is preferable to stir the mixture when the materials are brought into contact (Paragraph 0025).
In the first synthesis step of method (2), Takeshi teaches a mechanical milling process to form a sulfide solid electrolyte in which organic solvent is added to lithium sulfide and other sulfides prior to milling, where the resulting product is dried to remove the solvent to obtain the solid electrolyte (Paragraph 0030). Thus, Takeshi teaches a process including steps of smoothing is performed followed by heating.
Takeshi discloses in the method of producing a solid electrolyte according to Example 4, an apparatus was used to obtain the sulfide solid electrolyte (Paragraph 0072). Takeshi teaches in the process, lithium sulfide and other sulfides are stirred in the presence of solvent in the reaction tank (Figure 3, Element 20), where the mixture is then transported by pump (Figure 4, Element 54) through the connecting pipe (Figure 3, Element 52) into the mill (Figure 3, Element 10). Takeshi teaches a portion of the mixture is removed from the mill and subjected to filtration and drying to obtain the powder solid electrolyte (Paragraph 0072).
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Figure 3 of Takeshi
Therefore, an exemplified by Example 4, Takeshi teaches an embodiment in which the synthesis steps (1) and (2) are used consecutively to form a sulfide solid electrolyte. Takeshi teaches the temperature of the reaction tank is heated by an oil bath (Figure 3, Element 40) and the mill is warmed by a heater (Figure 3, Element 30) (Paragraph 0072). Therefore, the mixture of the lithium sulfide and other sulfides (electrolyte precursor) that is exiting the reaction tank and entering the mill is considered to be exposed to at least some degree of heating between the stirring and the smoothing (milling) treatment, meeting the instant claimed limitations.
Thus, Takeshi teaches the method of producing a crystalline sulfide solid electrolyte comprising:
mixing (via stirring blade 24 in the reaction tank 20) a raw material inclusion containing at least one selected from the group consisting of a lithium atom, a sulfur atom (lithium sulfide), and a phosphorus atom (phosphorous sulfide) and a complexing agent (tetrahydrofuran, ethyl acetate) without using a grinding machine (stirring) (method 1 of Takeshi) to obtain an electrolyte precursor,
heating the electrolyte precursor (either by the oil bath prior to exiting the reaction tank or by the heater in the mill) to obtain a complex degradate,
smoothing (milling, in accordance with the instant disclosure describing smoothing treatment, Paragraphs 0013 and 00142) the complex degradate to obtain a smoothed complex degradate (method 2 of Takeshi), and
heating the smoothed complex degradate (Paragraph 0072), meeting the instant claimed limitations.
Regarding claim 2, Takeshi teaches a method according to claim 1, wherein the raw material inclusion further contains a halogen atom (boron sulfide), as discussed above.
Regarding claim 5, Takeshi teaches a method according to claim 1, wherein the smoothing treatment is carried out using at least one apparatus selected from the group consisting of a grinding machine (mill) (Figure 3, Element 10) and stirring machine (reaction tank and stirrer) (Figure 3, Elements 24 and 20), as discussed above.
Regarding claim 6, Takeshi teaches a method according to claim 1, wherein the smoothing treatment is carried out using a solvent (organic solvent and additional solvent), as discussed above (Paragraph 0017).
Regarding claim 7, Takeshi teaches a method according to claim 1, wherein the smoothing is carried out using at least one apparatus selected from the group consisting of a ball mill and a bead mill, (Paragraph 0029).
Regarding claim 8, Takeshi teaches a method according to claim 6.
Takeshi teaches the organic solvent used in the synthesis of the solid electrolyte is preferably a hydrocarbon solvent, such as hexane, pentane, 2-ethylhexane, heptane, decane, cyclohexane, toluene, xylene, ethylbenzene, decalin, etc (Paragraph 0018). The hydrocarbon solvents taught by Takeshi are considered non-polar, meeting the instant claimed limitations.
Further, Takeshi teaches that the additional solvents used in addition to the hydrocarbon solvent include acetone, methyl ethyl ketone, tetrahydrofuran, ethyl acetate, dichloromethane, and chlorobenzene (Paragraph 0020). The additional solvents taught by Takeshi are considered aprotic, further meeting the instant claimed limitations.
Regarding claim 12, Takeshi teaches a method of producing a crystalline sulfide solid electrolyte (discussed above in the rejection of claim 1), the method comprising:
mixing (via stirring blade 24 in the reaction tank 20) a raw material inclusion containing at least one selected from the group consisting of a lithium atom, a sulfur atom (lithium sulfide), and a phosphorus atom (phosphorous sulfide) and a complexing agent (tetrahydrofuran, ethyl acetate) without using a grinding machine (stirring) (method 1 of Takeshi) to obtain an electrolyte precursor,
heating the electrolyte precursor (either by the oil bath prior to exiting the reaction tank or by the heater in the mill) to obtain a complex degradate,
mechanically processing (milling, in accordance with the instant disclosure describing mechanical treatment, Paragraphs 0013 and 00142) the complex degradate to obtain a smoothed complex degradate (method 2 of Takeshi), and
heating the modified complex degradate (Paragraph 0072), meeting the instant claimed limitations.
Regarding claim 13, Takeshi teaches a method according to claim 1, wherein the electrolyte precursor is obtained by mixing the raw material inclusion using a stirrer (Paragraph 0025) or a mixer (Paragraph 0017).
Regarding claim 14, Takeshi teaches a method according to claim 12, wherein the electrolyte precursor is obtained by mixing the raw material inclusion using a stirrer (Paragraph 0025) or a mixer (Paragraph 0017).
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.
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Takeshi as applied to claims 1-2, 5-8, 12-14 above, further in view of Tomoyuki (Japanese Patent Publication No. 2019200856 A).
Regarding claim 3, as described above, Takeshi teaches in the method to form the electrolyte, it is preferable to mix lithium sulfide with the other sulfides in an organic solvent which may be supplemented by additional solvent (Paragraphs 0017 and 0020). Takeshi teaches the solvents that may be added as needed include acetone, methyl ethyl ketone, tetrahydrofuran, ethanol, butanol, ethyl acetate, dichloromethane, and chlorobenzene.
Takeshi does not explicitly teach the mixing step of the above described method of producing a crystalline sulfide solid electrolyte comprising a first mixing using a first complexing agent and a second mixing using a second complexing agent that differs from the first complexing agent.
However, Tomoyuki discloses a method for producing a sulfide-based solid electrolyte for a solid-state secondary battery (Paragraph 0001) comprising a first step (first mixing) of mixing at least Li2S, P2S5 and LiI (a lithium atom, a sulfur atom, a phosphorus atom, and a halogen, as required by claims 1-2) in a first solvent (first complexing agent) to obtain a precursor, and a second step (second mixing) of reacting the precursor in a second solvent (second complexing agent) to obtain a sulfide-based solid electrolyte (Paragraph 0023).
Tomoyuki teaches the first solvent is a cyclic ether compound substituted or unsubstituted by an alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms and provides suitable examples of the first solvent including tetrahydrofuran and tetrahydropyran in order for the reaction between Li2S and P2S5 can be suitably advanced while preventing decomposition of the raw material (Paragraphs 0040-0041). As the instant disclosure provides that tetrahydrofuran and tetrahydrofuran are suitable complexing agents to use in the method (Paragraph 0089), the first solvent is considered a first complexing agent, meeting the instant claimed limitations.
Tomoyuki teaches the second solvent is an alkoxy group-substituted hydrocarbon (Paragraph 0050) to further promote the reaction to form a sulfide solid electrolyte (Paragraph 0050) and provides suitable examples of the second solvent including dimethoxyethane, diethoxyethane, diisopropyl ether and cyclopentylmethyl ether (Paragraph 0056). As the instant disclosure provides that dimethoxyethane, diethoxyethane, diisopropyl ether and cyclopentylmethyl ether are suitable complexing agents to use in the method (Paragraph 0089), the second solvent is considered a second complexing agent, meeting the instant claimed limitations.
Tomoyuki teaches a two-stage synthesis reaction using a specific solvent in each stage to synthesize halogenated sulfide-based solid electrolytes in a liquid phase in order to advantageously obtain a characteristic crystal structure, a relatively low activation energy, and a relatively high ionic conductivity (Paragraph 0030).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the mixing step of the method of Takeshi to incorporate the teachings of Tomoyuki in which mixing comprises a first mixing using a first complexing agent and a second mixing using a second complexing agent that differs from the first complexing agent. Doing so would result in promotion of the reaction of the raw materials and a final sulfide solid electrolyte product which has a characteristic crystal structure, a relatively low activation energy, and a relatively high ionic conductivity, as recognized by Tomoyuki.
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Takeshi in view of Tomoyuki as applied to claim 3 above, further in view of Platt (U.S. Patent Publication No. 20220123359 A1)
Regarding claim 4, modified Takeshi teaches a method according to claim 3.
The modification of Takeshi by Tomoyuki discussed above resulted in the first and second complexing agents disclosed by Tomoyuki into the mixing method of Takeshi.
Modified Takeshi is silent as to the second complexing agent is a complexing agent capable of forming a complex that contains Li3PS4.
However, as discussed above, Tomoyuki teaches tetrahydrofuran and tetrahydropyran as suitable first solvents (Paragraph 0040-0041) and dimethoxyethane, diethoxyethane, diisopropyl ether and cyclopentylmethyl ether as suitable second solvents (Paragraph 0056).
As the instant disclosure provides that dimethoxyethane, diethoxyethane, diisopropyl ether and cyclopentylmethyl ether are suitable second complexing agents to use in the method (Paragraph 0089), the second solvent is considered a second complexing agent. It is reasonable to presume that the second complexing agent of Takeshi in view of Tomoyuki is a complexing agent capable of forming a complex that contains Li3PS4, meeting the instant claimed limitations. Support for said presumption is found in the shared identity of the second solvent of Takeshi in view of Tomoyuki and the second complexing agent of the instant disclosure.
Takeshi does not teach the first complexing agent is a complexing agent capable of forming a complex that contains Li3PS4 and a halogen atom.
However, Platt discloses a method of forming a sulfide solid electrolyte (Paragraph 0006) using a multi-stage solution process to form the solid electrolyte (Paragraph 0007). Platt teaches a first solvent used in combination with raw materials including phosphorous, lithium, and sulfur atoms (aligning with the instant claim 1) (Paragraph 0016), which may be suitably various compounds including cyclic ether molecules and ring amine molecules, such as tetrahydrofuran and n-methyl piperidine, respectively (Paragraph 0017).
Therefore, given the general teachings of Platt, Takeshi, and Tomoyuki, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to substitute n-methyl piperidine for tetrahydrofuran as the first complexing agent in the method of producing a sulfide solid electrolyte disclosed by Tomoyuki, because Platt teaches the solvent may suitably be selected as a cyclic ether or a ring amine in order to facilitate the reaction between the lithium, sulfur, and phosphorus-containing raw materials. The substitution would have been one known element for another and one of ordinary skill in the pertinent art would reasonably expect the predictable result that the sulfide solid electrolyte would be useful as an electrolyte in a solid-state battery. See MPEP § 2143.I.(B).
As the instant disclosure provides that methylpiperidine is a suitable first complexing agent to use in the method (Paragraph 0079), the first solvent of n-methyl piperidine of Takeshi and Tomoyuki in view of Platt is considered a first complexing agent, meeting the instant claimed limitations.
It is reasonable to presume that the first complexing agent of Takeshi and Tomoyuki in view of Platt is a complexing agent capable of forming a complex that contains Li3PS4 and a halogen atom, meeting the instant claimed limitations. Support for said presumption is found in the shared identity of the first solvent of Takeshi and Tomoyuki in view of Platt and the first complexing agent of the instant disclosure.
Claims 9-10 are rejected under 35 U.S.C. 103 as being unpatentable over Takeshi as applied to claims 1-2, 5-8, 12-14 above further in view of Nakayama (U.S. Patent Publication No. 20220263122 A1).
Regarding claim 9, Takeshi teaches a method according to claim 1.
Takeshi is silent as to a ratio of Sb/Sa is 1.0 or more and 10.0 or less, where Sb is a specific surface area of the complex degradate before the smoothing and Sa is a specific surface area of the smoothed complex degradate.
However, Nakayama discloses a method of producing a sulfide solid electrolyte having a small particle size and a low specific surface area (Abstract) achieved by pulverization (Paragraph 0006). Nakayama teaches in the method of manufacturing the sulfide solid electrolyte an intermediate of a sulfide solid electrolyte that contains lithium, phosphorous, and sulfur elements in step 1-1 and then subjecting the intermediate to a thermal treatment followed by pulverization (smoothing) in step 1-2 (Paragraph 0077), which may be a wet pulverization using a ball or bead mill (Paragraph 0100), aligning with the smoothing conditions of the instant disclosure.
Nakayama teaches that the thermally-treated intermediate is preferably pulverized so that the ratio of the surface area of the intermediate (before pulverization) (Sb) to the surface area of the product (after pulverization) (Sa) is 1 or more (Paragraph 0107). The range of Sb/Sa of Nakayama overlaps with the range of the instant claim. Therefore, prima facie obviousness is established. See MPEP 2144.05 (I).
Nakayama teaches that an increase in the specific surface area of the sulfide solid electrolyte results in an increase in the solvent adsorbed on the particle surface, requiring more drying which increases production costs and decreases productivity. Accordingly, there is a need to reduce bot the particle size and specific surface area of the sulfide solid electrolyte (Paragraphs 0059, 0063-0064).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the smoothing step of the production method of Takeshi to incorporate the teachings of Nakayama in which a ratio of Sb/Sa is 1.0 or more, where Sb is a specific surface area of the complex degradate before the smoothing and Sa is a specific surface area of the smoothed complex degradate. Doing so would advantageously result in the prevention of solvent adsorption onto the particle surface, as recognized by Nakayama.
Regarding claim 10, Takeshi teaches a method according to claim 1.
Takeshi is silent as to wherein a ratio of D50b/D50a is 1.0 or more and 100.0 or less, where D50b is an average particle diameter of the complex degradate before the smoothing and D50a is an average particle diameter of the smoothed complex degradate.
However, as discussed above, Nakayama discloses a method of producing a sulfide solid electrolyte having a small particle size and a low specific surface area (Abstract) achieved by pulverization (Paragraph 0006). Nakayama teaches in the method of manufacturing the sulfide solid electrolyte an intermediate of a sulfide solid electrolyte that contains lithium, phosphorous, and sulfur elements in step 1-1 and then subjecting the intermediate to a thermal treatment followed by pulverization (smoothing) in step 1-2 (Paragraph 0077), which may be a wet pulverization using a ball or bead mill (Paragraph 0100), aligning with the smoothing conditions of the instant disclosure.
Nakayama teaches that the thermally-treated intermediate is preferably pulverized so that the ratio of the diameter (D50) of the intermediate (before pulverization) (D50b) to the surface area of the product (after pulverization) (D50a) is 0.10 or more and 10 or less (Paragraph 0081). The range of D50b/ D50a of Nakayama overlaps with the range of the instant claim. Therefore, prima facie obviousness is established. See MPEP 2144.05 (I).
Nakayama teaches that when the ratio of the diameters before and after pulverization lie within the range disclosed, the pulverized sulfide solid electrolyte product has a spherical shape and the generation of fine particles is suppressed (Paragraph 0082).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the smoothing step of the production method of Takeshi to incorporate the teachings of Nakayama in which a ratio of D50b/ D50a is 0.10 or more and 10.0 or less, where D50b is a specific surface area of the complex degradate before the smoothing and D50a is a specific surface area of the smoothed complex degradate. Doing so would advantageously result in a spherical sulfide solid electrolyte and prevent the formation of fine particles as a result of pulverization, as recognized by Nakayama.
Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Takeshi as applied to claims 1-2, 5-8, 12-14 above further in view of Mizuno (Non-Patent Literature “New Lithium-Ion Conducting Crystal Obtained by Crystallization of the Li2S-P2S5 Glasses”) and Hayashi (Non-Patent Literature “Formation of Superionic Crystals from Mechanically Milled Li2S-P2S5 Glasses”).
Regarding claim 11, Takeshi teaches a method according to claim 1.
Takeshi is silent as to the crystalline sulfide solid electrolyte contains a thio-LISICON Region II-type crystal structure.
However, Mizuno discloses a variety of sulfide-based solid electrolytes (glass ceramics) (Abstract) and teaches that the conductivity and activation energy of the glass ceramics largely depends on the precipitated crystalline phases and their crystallinity, thus the compositions and heat treatment of the glass ceramics are very important to developing highly conductive materials (Page A603, Column 1, Paragraph 3). As illustrated in Table 1 of Mizuno, the composition of the glass ceramics and the crystallization temperature affected the major precipitated crystalline phase, with a thio-LISICON II analog formed at Li2S content and crystallization temperatures of 80% / 225ºC and 87.5% / 220ºC, respectively.
Mizuno teaches that the conductivity of the thio-LISICON II analogs show high conductivity at room temperature (Page A604, Column 2, Paragraph 1) with Hayashi providing support that the conductivities of glass ceramics depend on the crystalline phases precipitated (Page 114, Column 2, Paragraph 1) with thio-LISICON region II structures showing much higher conductivities compared to LISICON region I and LISICON region III crystal structures (Page 112; Column 2; Paragraph 3).
Takeshi, discussed above, teaches in the method of forming the sulfide solid electrolyte that the temperature of crystallization is between 150ºC - 400ºC (Paragraph 0010) and the amount of lithium sulfide is preferably 30 mol% to 95 mol% (Paragraph 0016). Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Takeshi to incorporate the teachings of Mizuno and Hayashi in which the crystallization temperature and the quantity of lithium sulfide of Takeshi is tuned in order to obtain a crystalline sulfide solid electrolyte contains a thio-LISICON Region II-type crystal structure. By adjusting these variables in the method of forming the sulfide solid electrolyte taught by Takeshi in view of Mizuno, a thio-LISICON Region II crystal structure may be precipitated having superior ionic conductivity, as recognized by Hayashi.
Claims 1-3, 5-10, 12-14 are rejected under 35 U.S.C. 103 as being unpatentable over Tomoyuki (Japanese Patent Publication No. 2019200856 A) in view of Nakayama (U.S. Patent Publication No. 20220263122 A1), as evidenced by Ito (Japanese Patent Publication No. 2020027715 A).
Tomoyuki teaches a method of producing a crystalline sulfide solid electrolyte (Paragraphs 0001, 0013). Tomoyuki teaches the method comprising a first step of mixing at least Li2S, P2S5 and LiI (a lithium atom, a sulfur atom, a phosphorus atom) in a first solvent (complexing agent) to obtain a precursor (Paragraph 0023).
Tomoyuki teaches suitable examples of the first solvent including tetrahydrofuran and tetrahydropyran in order for the reaction between Li2S and P2S5 can be suitably advanced while preventing decomposition of the raw material (Paragraphs 0040-0041). As the instant disclosure provides that tetrahydrofuran and tetrahydrofuran are suitable complexing agents to use in the method (Paragraph 0089), the first solvent of Tomoyuki is considered a complexing agent, meeting the instant claimed limitations.
Tomoyuki teaches in the mixing step, stirring is performed in order to mix the raw materials and obtain a uniform reaction (Paragraph 0047). Tomoyuki teaches heating performed at the end of the production process in order to isolate the solvents used in the mixing process (Paragraph 0065).
Thus, Tomoyuki teaches the method of producing a crystalline sulfide solid electrolyte comprising:
mixing a raw material inclusion containing at least one selected from the group consisting of a lithium atom, a sulfur atom, and a phosphorus atom (Li2S and P2S5) and a complexing agent (first solvent of Tomoyuki) without using a grinding machine (stirring) to obtain an electrolyte precursor
heating the electrolyte precursor to obtain a complex degradate
meeting the instant claimed limitations.
Tomoyuki is silent as to the method of producing a crystalline sulfide solid electrolyte comprising smoothing the complex degradate to obtain a smoothed complex degradate and heating the smoothed complex degradate.
However, Nakayama discloses a method of producing a sulfide solid electrolyte having a small particle size and a low specific surface area (Abstract) including a step (1-1) of providing an intermediate sulfide solid electrolyte that contains lithium, phosphorous, and sulfur elements and a step (1-2) of subjected the intermediate provided in step (1-1) to thermal treatment and pulverizing the thermally-treated product to obtain a pulverized product (Paragraph 0077).
Nakayama teaches the intermediate in step (1-1) obtained by providing a raw material powder which contains the raw materials needed for the composition of the intermediate (Paragraphs 0089-0090). Nakayama further teaches the mixture powder containing one or more lithium-containing compounds, phosphorous-containing compounds, sulfur-containing compounds, and halogen-containing compounds, which are mixed in order to obtain the intermediate (Paragraphs 0091-0093).
Thus, the complex degradate obtained by the mixing and heating of Tomoyuki above (comprising lithium, phosphorous, sulfur, and halogen) is equated with the intermediate that is thermally treated (sintered product) of Nakayama.
Thus, Nakayama teaches the complex degradate is smoothed (pulverization via milling, in accordance with the instant disclosure describing smoothing treatment, Paragraphs 0013 and 00142) (step 1-2 of Nakayama) (Paragraphs 0077 and 0100). In examples where the pulverization is performed with wet milling, the obtained pulverized product of Nakayama was subjected to drying in order to obtained the final product, meeting the instant claimed limitations.
Nakayama discloses the pulverization and heating steps of the intermediate in the process of forming the sulfide solid electrolyte in order to control the particle shape and size of the resulting sulfide solid electrolyte product (Paragraph 0079).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of producing a crystalline sulfide solid electrolyte of Tomoyuki to incorporate the teachings of Nakayama in which the complex degradate is smoothed to obtain a smoothed complex degradate and then heated. Doing so would advantageously result in the desired spherical shape of the resulting sulfide solid electrolyte with suitable diameter and surface area characteristics, as recognized by Nakayama. Thus modification is further supported by Ito, who recognizes that in the method of producing a sulfide solid electrolyte, it is possible to add additional treatment steps such as crushing (smoothing) between the mixing and firing step as well as after the firing step (Paragraph 15).
Regarding claim 2, modified Tomoyuki teaches the method according to claim 1, wherein the raw material inclusion further contains a halogen atom. As discussed above, Tomoyuki teaches lithium iodide in the mixing step of the method (Paragraph 0009), therefore a halogen atom is comprised in the raw material inclusion of the above method, meeting the instant claimed limitations.
Regarding claim 3, modified Tomoyuki teaches the method according to claim 1.
In the method of producing a sulfide solid electrolyte disclosed by Tomoyuki, the mixing step is a two-stage step using a specific solvent in each stage to synthesize halogenated sulfide-based solid electrolytes in a liquid phase in order to advantageously obtain a characteristic crystal structure, a relatively low activation energy, and a relatively high ionic conductivity.
However, Tomoyuki teaches a first step (first mixing) of mixing at least Li2S, P2S5 and LiI (a lithium atom, a sulfur atom, a phosphorus atom, and a halogen, as required by claims 1-2) in a first solvent (first complexing agent) to obtain a precursor, and a second step (second mixing) of reacting the precursor in a second solvent (second complexing agent) to obtain a sulfide-based solid electrolyte (Paragraph 0023).
Tomoyuki teaches the first solvent is a cyclic ether compound substituted or unsubstituted by an alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms and provides suitable examples of the first solvent including tetrahydrofuran and tetrahydropyran in order for the reaction between Li2S and P2S5 can be suitably advanced while preventing decomposition of the raw material (Paragraphs 0040-0041). As the instant disclosure provides that tetrahydrofuran and tetrahydrofuran are suitable complexing agents to use in the method (Paragraph 0089), the first solvent is considered a first complexing agent, meeting the instant claimed limitations.
Tomoyuki teaches the second solvent is an alkoxy group-substituted hydrocarbon (Paragraph 0050) to further promote the reaction to form a sulfide solid electrolyte (Paragraph 0050) and provides suitable examples of the second solvent including dimethoxyethane, diethoxyethane, diisopropyl ether and cyclopentylmethyl ether (Paragraph 0056). As the instant disclosure provides that dimethoxyethane, diethoxyethane, diisopropyl ether and cyclopentylmethyl ether are suitable complexing agents to use in the method (Paragraph 0089), the second solvent is considered a second complexing agent, meeting the instant claimed limitations.
Therefore, Tomoyuki teaches the mixing step comprises a first mixing using a first complexing agent and a second mixing using a second complexing agent that differs from the first complexing agent, meeting the instant claimed limitations.
Regarding claim 5, Tomoyuki in view of Nakayama teaches a method according to claim 1.
As discussed above, Nakayama taught the steps of the instant method direct toward smoothing the complex degradate and heating the smoothed complex degradate.
Nakayama teaches the smoothing (pulverization) treatment is carried out using a grinding machine (jet mill, ball mill, bead mill) (Paragraph 0100).
Therefore, Tomoyuki in view of Nakayama teaches the smoothing treatment is carried out using a grinding machine (mill), meeting the instant claimed limitations.
Regarding claim 6, Tomoyuki in view of Nakayama teaches a method according to claim 1.
As discussed above, Nakayama taught the steps of the instant method direct toward smoothing the complex degradate and heating the smoothed complex degradate.
Nakayama teaches the smoothing (pulverization) treatment can be pulverized by a wet method with a hydrocarbon solvent (Paragraph 0100), meeting the instant claimed limitations.
Regarding claim 7, Tomoyuki in view of Nakayama teaches a method according to claim 1.
As discussed above, Nakayama taught the steps of the instant method direct toward smoothing the complex degradate and heating the smoothed complex degradate.
Nakayama teaches the smoothing (pulverization) treatment is carried out using a grinding machine including a ball mill and bead mill (Paragraph 0100), meeting the instant claimed limitations.
Regarding claim 8, Tomoyuki in view of Nakayama teaches a method according to claim 6.
As discussed above, Nakayama taught the steps of the instant method direct toward smoothing the complex degradate and heating the smoothed complex degradate.
Nakayama teaches the wet pulverization performed using a hydrocarbon solvent, which is known in the art to be non-polar and aprotic, meeting the instant claimed limitations.
Regarding claim 9, Tomoyuki teaches a method according to claim 1.
Tomoyuki is silent as to a ratio of Sb/Sa is 1.0 or more and 10.0 or less, where Sb is a specific surface area of the complex degradate before the smoothing and Sa is a specific surface area of the smoothed complex degradate.
However, in the method of producing a sulfide solid electrolyte of Nakayama described above, Nakayama teaches that the thermally-treated intermediate is preferably pulverized so that the ratio of the surface area of the intermediate (before pulverization) (Sb) to the surface area of the product (after pulverization) (Sa) is 1 or more (Paragraph 0107). The range of Sb/Sa of Nakayama overlaps with the range of the instant claim. Therefore, prima facie obviousness is established. See MPEP 2144.05 (I).
Nakayama teaches that an increase in the specific surface area of the sulfide solid electrolyte results in an increase in the solvent adsorbed on the particle surface, requiring more drying which increases production costs and decreases productivity. Accordingly, there is a need to reduce bot the particle size and specific surface area of the sulfide solid electrolyte (Paragraphs 0059, 0063-0064).
Therefore, in the modification of Tomoyuki by Nakayama to incorporate the smoothing of the complex degradate and the heating of the smoothed complex degradate disclosed Nakayama, it would be further obvious to the ordinary artisan that the inclusion of these steps of Nakayama would result in the ratio of the surface area of the intermediate (before pulverization) (Sb) to the surface area of the product (after pulverization) (Sa) that is disclosed by Nakayama to result from the smoothing/pulverization treatment.
Thus, Tomoyuki in view of Nakayama teaches a ratio of Sb/Sa is 1.0 or more, where Sb is a specific surface area of the complex degradate before the smoothing and Sa is a specific surface area of the smoothed complex degradate, in order to prevent excessive solvent adsorption onto the particle surface, as recognized by Nakayama.
Regarding claim 10, Tomoyuki teaches a method according to claim 1.
Tomoyuki is silent as to wherein a ratio of D50b/D50a is 1.0 or more and 100.0 or less, where D50b is an average particle diameter of the complex degradate before the smoothing and D50a is an average particle diameter of the smoothed complex degradate.
However, in the method of producing a sulfide solid electrolyte of Nakayama described above, Nakayama teaches that the thermally-treated intermediate is preferably pulverized so that the ratio of the diameter (D50) of the intermediate (before pulverization) (D50b) to the surface area of the product (after pulverization) (D50a) is 0.10 or more and 10 or less (Paragraph 0081). The range of D50b/ D50a of Nakayama overlaps with the range of the instant claim. Therefore, prima facie obviousness is established. See MPEP 2144.05 (I).
Nakayama teaches that when the ratio of the diameters before and after pulverization lie within the range disclosed, the pulverized sulfide solid electrolyte product has a spherical shape and the generation of fine particles is suppressed (Paragraph 0082). Accordingly, there is a need to reduce bot the particle size and specific surface area of the sulfide solid electrolyte (Paragraphs 0059, 0063-0064).
Therefore, in the modification of Tomoyuki by Nakayama to incorporate the smoothing of the complex degradate and the heating of the smoothed complex degradate disclosed Nakayama, it would be further obvious to the ordinary artisan that the inclusion of these steps of Nakayama would result in the ratio of the diameter of the intermediate (before pulverization) (D50b) to the diameter of the product (after pulverization) (D50a) that is disclosed by Nakayama to result from the smoothing/pulverization treatment.
Thus, Tomoyuki in view of Nakayama teaches a ratio of D50b/ D50a is 0.10 or more and 10.0 or less, where D50b is a specific surface area of the complex degradate before the smoothing and D50a is a specific surface area of the smoothed complex degradate, in order to obtain a spherical sulfide solid electrolyte and prevent the formation of fine particles as a result of pulverization, as recognized by Nakayama.
Regarding claim 12, Tomoyuki in view of Nakayama teaches a method of producing a crystalline sulfide solid electrolyte (discussed above in the rejection of claim 1), the method comprising:
mixing a raw material inclusion containing at least one selected from the group consisting of a lithium atom, a sulfur atom and a phosphorus atom and a complexing agent without using a grinding machine (stirring) to obtain an electrolyte precursor,
heating the electrolyte precursor to obtain a complex degradate,
mechanically processing (milling, in accordance with the instant disclosure describing mechanical treatment, Paragraphs 0013 and 00142) the complex degradate to obtain a smoothed complex degradate (step 102 of Nakayama), and
heating the modified complex degradate, meeting the instant claimed limitations.
Regarding claim 13, Tomoyuki teaches a method according to claim 1, wherein the electrolyte precursor is obtained by mixing the raw material inclusion using a stirrer (Paragraph 0047).
Regarding claim 14, Tomoyuki teaches a method according to claim 12, wherein the electrolyte precursor is obtained by mixing the raw material inclusion using a stirrer (Paragraph 0047).
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Tomoyuki in view of Nakayama as applied to claims 1-3, 5-10, 12-14 above, further in view of Platt (U.S. Patent Publication No. 20220123359 A1)
Regarding claim 4, modified Tomoyuki teaches a method according to claim 3.
Tomoyuki is silent as to the second complexing agent is a complexing agent capable of forming a complex that contains Li3PS4.
However, as discussed above, Tomoyuki teaches a first step (first mixing) of mixing at least Li2S, P2S5 and LiI in a first solvent (first complexing agent) to obtain a precursor, and a second step (second mixing) of reacting the precursor in a second solvent (second complexing agent) to obtain a sulfide-based solid electrolyte (Paragraph 0023).
Further discussed above, Tomoyuki teaches tetrahydrofuran and tetrahydropyran as suitable first solvents (Paragraph 0040-0041) and dimethoxyethane, diethoxyethane, diisopropyl ether and cyclopentylmethyl ether as suitable second solvents (Paragraph 0056).
As the instant disclosure provides that dimethoxyethane, diethoxyethane, diisopropyl ether and cyclopentylmethyl ether are suitable second complexing agents to use in the method (Paragraph 0089), the second solvent is considered a second complexing agent. It is reasonable to presume that the second complexing agent of Tomoyuki is a complexing agent capable of forming a complex that contains Li3PS4, meeting the instant claimed limitations. Support for said presumption is found in the shared identity of the second solvent of Tomoyuki and the second complexing agent of the instant disclosure.
Takeshi does not teach the first complexing agent is a complexing agent capable of forming a complex that contains Li3PS4 and a halogen atom.
However, Platt discloses a method of forming a sulfide solid electrolyte (Paragraph 0006) using a multi-stage solution process to form the solid electrolyte (Paragraph 0007). Platt teaches a first solvent used in combination with raw materials including phosphorous, lithium, and sulfur atoms (aligning with the instant claim 1) (Paragraph 0016), which may be suitably various compounds including cyclic ether molecules and ring amine molecules, such as tetrahydrofuran and n-methyl piperidine, respectively (Paragraph 0017).
Therefore, given the general teachings of Platt and Tomoyuki, it would have been obvious to one of ordinary skill in the pertinent art before the effective filing date of the claimed invention to substitute n-methyl piperidine for tetrahydrofuran as the first compelxing agent in the method of producing a sulfide solid electrolyte disclosed by Tomoyuki, because Platt teaches the solvent may suitably be selected as a cyclic ether or a ring amine in order to facilitate the reaction between the lithium, sulfur, and phosphorus-containing raw materials. The substitution would have been one known element for another and one of ordinary skill in the pertinent art would reasonably expect the predictable result that the sulfide solid electrolyte would be useful as an electrolyte in a solid-state battery. See MPEP § 2143.I.(B).
As the instant disclosure provides that methylpiperidine is a suitable first complexing agent to use in the method (Paragraph 0079), the first solvent of n-methyl piperidine of Tomoyuki in view of Platt is considered a first complexing agent, meeting the instant claimed limitations.
It is reasonable to presume that the first complexing agent of Tomoyuki in view of Platt is a complexing agent capable of forming a complex that contains Li3PS4 and a halogen atom, meeting the instant claimed limitations. Support for said presumption is found in the shared identity of the first solvent of Tomoyuki in view of Platt and the first complexing agent of the instant disclosure.
Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Tomoyuki in view of Nakayama as applied to claims 1-3, 5-10, 12-14 above, further in view of Mizuno (Non-Patent Literature “New Lithium-Ion Conducting Crystal Obtained by Crystallization of the Li2S-P2S5 Glasses”) and Hayashi (Non-Patent Literature “Formation of Superionic Crystals from Mechanically Milled Li2S-P2S5 Glasses”).
Tomoyuki is silent as to the crystalline sulfide solid electrolyte contains a thio-LISICON Region II-type crystal structure.
However, Mizuno discloses a variety of sulfide-based solid electrolytes (glass ceramics) (Abstract) and teaches that the conductivity and activation energy of the glass ceramics largely depends on the precipitated crystalline phases and their crystallinity, thus the compositions and heat treatment of the glass ceramics are very important to developing highly conductive materials (Page A603, Column 1, Paragraph 3). As illustrated in Table 1 of Mizuno, the composition of the glass ceramics and the crystallization temperature affected the major precipitated crystalline phase, with a thio-LISICON II analog formed at Li2S content and crystallization temperatures of 80% / 225ºC and 87.5% / 220ºC, respectively.
Mizuno teaches that the conductivity of the thio-LISICON II analogs show high conductivity at room temperature (Page A604, Column 2, Paragraph 1) with Hayashi providing support that the conductivities of glass ceramics depend on the crystalline phases precipitated (Page 114, Column 2, Paragraph 1) with thio-LISICON region II structures showing much higher conductivities compared to LISICON region I and LISICON region III crystal structures (Page 112; Column 2; Paragraph 3).
Tomoyuki, discussed above, teaches in the method of forming the sulfide solid electrolyte that the ratio of lithium sulfide (Li2S) is not limited and may be changed as appropriate so that a desired compound is obtained (Paragraphs 0035-0036). Nakayama, as discussed above modified Tomoyuki to teach the final steps of the method, teaches the smoothing performed with a force to maintain crystallinity (Paragraph 0093) and thermal treatment performed to alleviate the strain of the solid electrolyte particles and increase crystallinity which is performed between 200ºC and 500ºC (Paragraph 0103).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified Tomoyuki in view of Nakayama to incorporate the teachings of Mizuno and Hayashi in which the crystallization temperature and the quantity of lithium sulfide are tuned in order to obtain a crystalline sulfide solid electrolyte contains a thio-LISICON Region II-type crystal structure. By adjusting these variables in the method of forming the sulfide solid electrolyte taught by Tomoyuki in view of Nakayama and Mizuno, a thio-LISICON Region II crystal structure may be precipitated having superior ionic conductivity, as recognized by Hayashi.
Conclusion
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/O.A.J./ Examiner, Art Unit 1789
/MARLA D MCCONNELL/ Supervisory Patent Examiner, Art Unit 1789