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 .
Response to Amendment
The amendment filed on 05/26/2026 has been entered. Claims 1-16, 18, 23-33, 35-39 and 41-46 are being examined while claim 40 is withdrawn.
Applicant’s amendments to the claims have not introduced new matter and are supported in the specification in at least [00162] of the instant specification.
Applicant’s amendment has sufficiently changed the scope of the claims such that the outstanding double patenting rejection made in the action mailed 02/24/2026 is overcome and accordingly that rejection is withdrawn.
Response to Arguments
Applicant’s arguments, see Pg. 7-9 filed 05/26/2026 with respect to claim 1 and 46, have been fully considered however are directed to limitations introduced in the amendment filed 05/26/2026, which postdates the final rejection mailed 02/24/2026.
Upon further search and consideration and as necessitated by the amendment, the 35 U.S.C. 103 rejections of independent claim 1 and 46 made on 02/24/2026 are withdrawn and a new grounds of rejection for independent claims 1 and 46 are made under 35 U.S.C. 103 as being unpatentable over Li et al. (CN103552990A English; cited in IDS dated 11/07/2024) in view of Otsuki et al. (JP6725876B2 English), with evidentiary support for the rejection of claim 1 provided by Basma et al. (J. Phys. Chem. B 2018, 122, 8963−8971).
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 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 1-5, 10-12, 15-16, 18, 23-25, 28-29, 35-39, and 44-45 are rejected under 35 U.S.C. 103 as being unpatentable over Li et al. (CN103552990A English; cited in IDS dated 11/07/2024) in view of Otsuki et al. (JP6725876B2 English), with evidentiary support for the rejection of claim 1 provided by Basma et al. (J. Phys. Chem. B 2018, 122, 8963−8971).
Note, the citations for Li are from the English-equivalent documents provided by the Examiner. The copies provided by Applicant only include an English abstract.
Regarding claim 1, Li teaches a method of preparing high-purity lithium sulfide comprising reacting lithium chloride (i.e. a first alkali metal salt) with sodium or potassium sulfohydrate (i.e. a first alkali metal hydrosulfide) in N-methyl pyrrolidone to produce a precipitate (i.e. second alkali metal salt precipitate) that is filtered off to provide a solution of lithium sulfide in N-methyl pyrrolidone that has its solvent removed prior to provide the high-purity lithium sulfide (i.e. a second sulfide) (Abstract; Claims 1, 4, 5; Pg. 2, par. 3-13; Pg. 2-3, Embodiment 1). N-methyl pyrrolidone is a polar solvent, as evidenced by Basma who teaches N-methyl pyrrolidone is a strongly polar solvent (Pg. 8963, left col.).
The claim further requires the first sulfide is present and that “the first sulfide is selected from the group consisting of K2S, Na2S, (NH4)2S, and mixtures thereof,” and “the first alkali metal hydrosulfide is an alkali metal hydrosulfide hydrate having a water content from about 20% to about 75% by weight,” to which Li is silent.
Otsuki teaches a method of preparing anhydrous alkali metal sulfides that includes reacting a alkali metal sulfide with a hydrous alkali metal hydrosulfide, where the alkali metal sulfide can include compounds such as lithium, sodium, potassium, rubidium, and cesium sulfide while the hydrated alkali metal hydrosulfide can include hydrates of compounds such as lithium, sodium, potassium, rubidium, and cesium hydrosulfide, where the alkali metal hydrosulfide comprises 10-80% by mass while the remaining mass% is balanced with water from the hydrate and aqueous solution (Abstract; Title; Pg. 2, par. 11-12). Otsuki teaching the remaining mass of the hydrated alkali metal hydrosulfide is met with water effectively teaches a water mass% of about 20-90%, which overlaps the claimed range. Mass% and weight% are equivalent terms. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP 2144.05 (I). In the instant case, the range taught by Otsuki (10-90 mass% water in the alkali metal hydrosulfide) overlaps with the claimed range (about 20% to about 75% by weight water content). Therefore, the range in Otsuki renders obvious the claimed range.
Advantageously, providing an alkali metal sulfide such as lithium, sodium, potassium, rubidium, and cesium sulfide with an alkali metal hydrosulfide such as lithium, sodium, potassium, rubidium, and cesium hydrosulfide with a water content from 10-90 mass% provides an alkali metal sulfide product with fine-grains and high purity (Pg. 2, par. 2-6; Pg. 3, par. 7).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to use an alkali metal sulfide and a hydrated alkali metal hydrosulfide containing 10-90 mass% water in the process of Li in order to provide a high purity alkali metal sulfide product with fine-grains, as taught by Otsuki.
Regarding claims 2-3, Li in view of Otsuki teach the method of claim 1 and Li further teaches the solvent is removed via vacuum to provide dry lithium sulfide product (Pg. 2, par. 13-15; Embodiment 1). Li teaches the lithium sulfide powder is 99% pure and that greater than 98% of the N-methyl pyrrolidone solvent is reclaimed (Pg. 2, par. 15).
Regarding claim 4, Li in view of Otsuki teach the method of claim 1 and 2 and Li further teaches the lithium sulfide powder is 99% pure and that greater than 98% of the N-methyl pyrrolidone solvent is reclaimed (Pg. 2, par. 15). In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP 2144.05 (I). In the instant case, the range taught by Li (greater than 98% of N-methyl pyrrolidone is recovered) overlaps with the claimed range (over 99% by weight of the polar solvent is removed). Therefore, the range in Li renders obvious the claimed ranges.
Regarding claim 5, Li in view of Otsuki teach the method of claim 1 and Li further teaches the solvent is removed via vacuum to provide dry lithium sulfide product (Pg. 2, par. 13-15; Embodiment 1).
Regarding claims 10-12, Li in view of Otsuki teach the method of claim 1 and Li further teaches the solution obtained following filtration includes lithium hydrogen sulfide (i.e. sulfur lithium hydride) that can be decomposed via heat treatment to provide lithium sulfide and only produces hydrogen sulfide (Abstract; Pg. 2, par. 8-10; Claim 4). Li teaches the decomposition of the sulfur lithium hydride (i.e. LiHS) only produces hydrogen sulfide in route to provide lithium sulfide as a solid (Pg. 2, par. 7-11; Claim 4).
Regarding claim 15, Li in view of Otsuki teach the method of claim 1 and Li further teaches the alkali metal salt precipitated is separated by filtration (Pg. 2, par. 4).
Regarding claim 16, Li in view of Otsuki teach the method of claim 1 and Li further teaches the solvent is removed via vacuum to provide dry lithium sulfide product (Pg. 2, par. 13-15; Embodiment 1). Removing the solvent by vacuum is equivalent to “reducing atmospheric pressure surrounding the supernatant” and also necessarily requires reducing the solvent amount.
Regarding claim 24, Li in view of Otsuki teach the method of claim 1, where Li teaches the first alkali metal salt is lithium chloride (LiCl) and the first alkali metal hydrosulfide is sodium hydrosulfide (NaHS) (Abstract; Claims 1 and 5).
The claim further requires the first sulfide is present and that “the first sulfide comprises Na2S,” to which Li is silent.
Otsuki teaches a method of preparing anhydrous alkali metal sulfides that includes reacting a alkali metal sulfide with a hydrous alkali metal hydrosulfide, where the alkali metal sulfide can include compounds such as lithium, sodium, potassium, rubidium, and cesium sulfide while the hydrated alkali metal hydrosulfide can include hydrates of compounds such as lithium, sodium, potassium, rubidium, and cesium hydrosulfide, where the alkali metal hydrosulfide comprises 10-80% by mass while the remaining mass% is balanced with water from the hydrate and aqueous solution (Abstract; Title; Pg. 2, par. 11-12).
Advantageously, providing an alkali metal sulfide such as lithium, sodium, potassium, rubidium, and cesium sulfide provides an alkali metal sulfide product with fine-grains and high purity (Pg. 2, par. 2-6; Pg. 3, par. 7).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to use an alkali metal sulfide, including sodium sulfide, in the process of Li in order to provide a high purity alkali metal sulfide product with fine-grains, as taught by Otsuki.
Regarding claim 25, Li in view of Otsuki teach the method of claim 1 and Li further teaches the reaction of lithium chloride and sodium sulfhydrate provides lithium sulfide and a sodium chloride precipitate, that is filtered (Pg.2-3, Embodiment 1; Abstract).
Regarding claims 28-29, Li in view of Otsuki teach the method of claim 1 and Li further teaches the lithium chloride is dissolved in the polar solvent, NMP, prior to adding sodium sulfhydrate, which is a solid measured in grams (Pg. 2, Embodiment 1).
Regarding claims 35-36, Li in view of Otsuki teach the method of claim 1 and Li further teaches a method of preparing high-purity lithium sulfide comprising reacting lithium chloride (i.e. a first alkali metal salt) with sodium or potassium sulfohydrate (i.e. a first alkali metal hydrosulfide is NaHS) in N-methyl pyrrolidone to produce a precipitate (i.e. second alkali metal salt precipitate) that is filtered off to provide a solution of lithium sulfide in N-methyl pyrrolidone that has its solvent removed prior to provide the high-purity lithium sulfide (i.e. a second sulfide of Li2S) (Abstract; Claims 1, 4, 5; Pg. 2, par. 3-13; Pg. 2-3, Embodiment 1).
Regarding claim 37, Li in view of Otsuki teach the method of claim 1 and Li further teaches the high-purity lithium sulfide product has a purity of greater than 99%, with less than 0.1% lithium sulfite impurities and less than 0.5% lithium sulphate impurities (Embodiment 1, Pg. 2, par. 14). Li teaches an embodiment where the lithium sulfide content is greater than 99%, the lithium sulfite content is less than 0.1%, and the lithium sulphate content is less than 0.5% (Pg. 3, Embodiment 3, par. 7).
Regarding claims 38-39, Li in view of Otsuki teach the method of claim 1.
Li does not explicitly teach the mass loss of the second sulfide (i.e. Li2S) is less than 10% when heated above 100 °C (Claim 38) and less than 13% when heated above 340°C (Claim 39).
However, the mass loss of the second sulfide is determined by the purity of the lithium sulfide material, in particular the presence of residual solvent with the material. This interpretation is supported in the instant specification in at least [0198].
In this regard, Li describes the high-purity lithium sulfide product has a purity of greater than 99%, with less than 0.1% lithium sulfite impurities and less than 0.5% lithium sulphate impurities (Embodiment 1, Pg. 2, par. 14). Li teaches an embodiment where the lithium sulfide content is greater than 99%, the lithium sulfite content is less than 0.1%, and the lithium sulphate content is less than 0.5% (Pg. 3, Embodiment 3, par. 7). Li teaches the solvent is removed via vacuum to provide dry lithium sulfide product (Pg. 2, par. 13-15; Embodiment 1). Li teaches the lithium sulfide powder is 99% pure and that greater than 98% of the N-methyl pyrrolidone solvent is reclaimed (Pg. 2, par. 15).
Comparatively, the instant specification describes an example where a Li2S material with a purity of 95.2% displays a mass loss of 9.35% when heated at 450°C ([00198]). The instant invention further describes over 99% of the solvent is removed from the powder ([0055]) and the purity of the Li2S is over 94% pure ([0048]).
Accordingly, while Li is silent regarding explicitly stating the mass loss of the lithium sulfide obtained by the synthesis, the high purity lithium sulfide possessing a purity of Li2S of greater than 99% with greater than 98% of the solvent removed would be expected to display a mass loss that is substantially similar to the mass loss of the lithium sulfide of the instant invention.
Once a reference teaching a product appearing to be substantially identical is made the basis of a rejection, and the examiner presents evidence or reasoning tending to show inherency, the burden shifts to the applicant to show an unobvious difference. "[T]he PTO can require an applicant to prove that the prior art products do not necessarily or inherently possess the characteristics of his [or her] claimed product. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433-34 (CCPA 1977)), see MPEP 2112. Applicant has not clearly shown an unobvious difference between the instant invention and the prior art’s product. Therefore, a rejection based alternatively on either 35 U.S.C. 102 or 35 U.S.C. 103 is eminently fair and acceptable.
Regarding claims 44-45, Li in view of Otsuki teach the method of claim 1 and Li further teaches the high-purity lithium sulfide product has a purity of greater than 99%, with less than 0.1% lithium sulfite impurities and less than 0.5% lithium sulphate impurities (Embodiment 1, Pg. 2, par. 14). A purity of greater than 99% for the Li2S would allow for only less than 1% of an impurity, including Na2S2O3 and Na2S2, to be present. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP 2144.05 (I). In the instant case, the range taught by Li (purity of greater than 99% for the Li2S) overlaps with the claimed ranges (97.5 to 99.9% free from Na2S2O3 (Claim 44); about 97.5 to about 99.9 % free from Na2S2 (Claim 45)). Therefore, the range in Li renders obvious the claimed ranges.
Claims 18 and 23 are rejected under 35 U.S.C. 103 as being unpatentable over Li et al. (CN103552990A English; cited in IDS dated 11/07/2024) in view of Otsuki et al. (JP6725876B2 English) and further in view of Yang et al. (CN112551491A English; cited in IDS dated 07/05/2023), with evidentiary support for claim 1 provided by Basma et al. (J. Phys. Chem. B 2018, 122, 8963−8971).
Regarding claims 18 and 23, Li in view of Otsuki teach the method of claim 1 and the claims further require the polar solvent is “substantially anhydrous” and “the polar solvent comprises at least one alcohol selected from the group consisting of ethanol, 1-propanol, 1-butanol, and mixtures thereof,” to which Li and Otsuki are silent.
Yang teaches a method of preparing lithium sulfide comprising reacting a lithium source and a sulfur compound under an inert atmosphere with at least one of anhydrous methanol, ethanol, propanol, isopropanol, butanol, and tert-butanol that have been treated with activated molecular sieves (Abstract; Claim 1 and 5; Pg. 3, par. 19).
Advantageously, the method of Yang, including application of anhydrous polar alcoholic solvents, provides a method that provides high purity lithium sulfide in a reproducible fashion that does not involve high temperature or high pressures to obtain the product (Pg. 4, par. 3-4).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to use an anhydrous poor solvent such as at least one of anhydrous methanol, ethanol, propanol, isopropanol, butanol, and tert-butanol, in the process of Li in order to provide high purity lithium sulfide in a reproducible fashion that does not involve high temperature or high pressures to obtain the product, as taught by Yang.
Claims 6-9 are rejected under 35 U.S.C. 103 as being unpatentable over Li et al. (CN103552990A English; cited in IDS dated 11/07/2024) in view of Otsuki et al. (JP6725876B2 English), and further in view of Sugawara et al. (JP2016207354A English), with evidentiary support for claim 1 provided by Basma et al. (J. Phys. Chem. B 2018, 122, 8963−8971).
Regarding claims 6-8, Li in view of Otsuki teach the process of claim 1 and the claims further require “adding a sulfur source to increase the purity of the second sulfide,” “wherein the sulfur source comprises one or more of elemental sulfur and H2S,” and “where the sulfur source is added at any step of the method prior to or during the removing of the polar solvent from the supernatant,” to which Li and Otsuki are silent.
Sugawara teaches a process for preparing a sulfide solid electrolyte that includes preparing lithium sulfide (Abstract; Pg. 2, par. 7). Sugawara teaches that an additional treatment can be performed with hydrogen sulfide gas (i.e. H2S) in order to improve the purity of the lithium sulfide (Pg. 4, par. 1). Sugawara teaches the H2S gas is brought into contact with an organic solvent prior to solvent removal (Pg. 3, par. 5-6). Advantageously, performing treatment with hydrogen sulfide prior to solvent removal improves the purity of the lithium sulfide and can convert other lithium containing impurities present in the sample into lithium sulfide (Pg. 4, par. 1; Pg. 8, Production Example 1).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to use a sulfur source such as hydrogen sulfide prior to solvent removal to further treat the lithium sulfide material to improve the purity of the lithium sulfide in the process of Li in order to improve the purity of the lithium sulfide by converting other lithium salts into lithium sulfide, as taught by Sugawara.
Regarding claim 9, Li in view of Otsuki teach the method of claim 1 and Li in view of Otsuki and further in view of Sugawara teach the method of claim 6.
Li further teaches the high-purity lithium sulfide product has a purity of greater than 99%, with less than 0.1% lithium sulfite impurities and less than 0.5% lithium sulphate impurities (Embodiment 1, Pg. 2, par. 14). Li teaches an embodiment where the lithium sulfide content is greater than 99%, the lithium sulfite content is less than 0.1%, and the lithium sulphate content is less than 0.5% (Pg. 3, Embodiment 3, par. 7). In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP 2144.05 (I). In the instant case, the range taught by Li (lithium sulfide product has a purity of greater than 99%) overlaps with the claimed range (second sulfide is 95% free by weight from Li3OCl). Therefore, the range in Li renders obvious the claimed range.
Claims 13-14 are rejected under 35 U.S.C. 103 as being unpatentable over Li et al. (CN103552990A English; cited in IDS dated 11/07/2024) in view of Otsuki et al. (JP6725876B2 English), and further in view of Yanagi et al. (US20180183096A1), with evidentiary support for claim 1 provided by Basma et al. (J. Phys. Chem. B 2018, 122, 8963−8971).
Regarding claims 13-14, Li in view of Otsuki teach the method of claim 1 and the claim further requires “adding an anti-solvent compound to the supernatant prior or directly following the precipitation of the second alkali metal salt” and “the anti-solvent is selected from the group consisting of hydrocarbon-based solvents, non-polar solvents, solvents with substantial miscibility in the polar solvent, solvents that increase the differential solubility of one or more of the second sulfide and second alkali metal hydrosulfide in the polar solvent in comparison to the second alkali metal salt, and combinations thereof,” to which Li and Otsuki are silent.
Yanagi teaches a method for preparing Li2S, where the raw materials, including LiHS and other lithium salts, are dissolved in good solvent that serves to dissolve the Li2S prior to adding a poor solvent in which the Li2S particles have low solubility in order to precipitate the solid ([0057]-[0059]). Yanagi teaches the poor solvent is a hydrocarbon solvent, with dodecane and tridecane as exemplary solvents ([0059]). Advantageously, the poor solvent not only allows precipitation of the target product, but provides the process an advantage of fast heat conduction and affords easy collection of the product ([0059]).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to add a poor solvent to the supernatant, such as dodecane and/or tridecane, in the process of Li in order to precipitate the target product while providing a fast heat conduction and affording easy collection of the product, as taught by Yanagi.
Claims 26, 30-33, and 42-43 are rejected under 35 U.S.C. 103 as being unpatentable over Li et al. (CN103552990A English; cited in IDS dated 11/07/2024) in view of Otsuki et al. (JP6725876B2 English) and further in view of Wolden et al. (US20210261411A1), with evidentiary support for claim 1 provided by Basma et al. (J. Phys. Chem. B 2018, 122, 8963−8971).
Regarding claim 26, Li in view of Otsuki teach the method of claim 1 and Li teaches the lithium chloride is dissolved in the polar solvent, NMP, prior to adding sodium sulfhydrate, which is a solid measured in grams (Pg. 2, Embodiment 1). Li is silent regarding separately dissolving a first sulfide in aliquots of polar solvent prior to adding the separate aliquots to form a mixture prior to adding the first alkali metal hydrogen sulfide. Otsuki is also silent regarding this limitation.
Wolden teaches a method of making anhydrous metal sulfide nanocrystals that comprises mixing a first sulfide salt (Abstract; [0013]), comprising Na2S, K2S, Rb2S, Cs2S, Fr2S, (NH4)2S, P2S5, NiS, and combinations thereof ([0017]), with a first lithium salt selected from the group consisting of lithium carbonate (Li2CO3), lithium sulfate (Li2SO4), lithium sulfite (Li2SO3), lithium amide (LiNH2), lithium nitride (LiN3), lithium nitrate (LiNO3), lithium phosphate (Li3PO4), and combinations thereof ([0018]), to provide Li2S (i.e. a second sulfide) and/or other metal or metalloid sulfides (MSn) (i.e. a third sulfide), where MSn is selected from the group consisting Cr2S3 , MnS, ReS2 , FeS2 , RuS2 , OsS2 , CoS2 , RhS2 , IrS3 , NiS2 , PdS, PtS, HfS2 , NbS2 , TaS2 , GeS2 , SiS2 , TiS2 , SnS2 , MoS2 , ZrS2 , CdS, ZnS, VS2 , WS2 , Al2S3 , CaS, and MgS ([0019]-[0023]). Wolden teaches a first solution of Na2S in ethanol is prepared, while a second solution of LiCl is dissolved in ethanol, prior to combining stoichiometric amounts of the first and seconds solutions ([0063]). Wolden teaching preparing separate solutions of Na2S and LiCl
Advantageously, preparing solutions of LiCl and Na2S allows solvent mixtures in which Li2S (the desired product) is not soluble in, or sparingly soluble in, which aids its recovering during the reaction once it has separated ([0041]-[0044]).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to prepare solutions of Na2S and LiCl separately prior to combining them in the process of Li in order to effectively precipitate Li2S by using solvents it is sparingly soluble in, as taught by Wolden.
Regarding claims 30-33, Li in view of Otsuki teach the method of claim 1 and the claims further require the ratio of solubility of the second sulfide to the solubility of the second alkali metal salt in the polar solvent is at least 90:10 (Claim 30), 97:3 (Claim 31), 99:1 (Claim 32), and 99.9:0.1 (Claim 33), to which Li and Otsuki are silent.
Wolden teaches the NaCl generated during the metathesis reaction is sparingly soluble in ethanol and is removed from solution by standard techniques while the Li2S is dissolved and is only recovered by removing solvent ([0063]-[0064]). Wolden further teaches X-ray diffraction data that displays the precipitate recovered from the solution metathesis reaction is exclusively NaCl (Fig. 2) while the solid recovered from the supernatant following solvent removal is exclusively Li2S (Fig. 3). This data is interpreted as essentially no Li2S is detected in the precipitate, meaning it remained in solution. Accordingly, a skilled artisan would expect the ratio of solubility of Li2S relative to NaCl in the polar solvent (i.e. ethanol) to be near infinite (i.e. Li2S is fully dissolved while NaCl is fully precipitated). In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP 2144.05 (I). In the instant case, the range taught by Wolden (near infinite solubility ratio of Li2S to NaCl) overlaps with the claimed ranges (the ratio of solubility of the second sulfide to the solubility of the second alkali metal salt in the polar solvent is at least 90:10 (Claim 30), 97:3 (Claim 31), 99:1 (Claim 32), and 99.9:0.1 (Claim 33)). Therefore, the range in Wolden renders obvious the claimed ranges.
Advantageously, the precipitation of NaCl due the drastically different solubility of NaCl against the target Li2S product allows NaCl to be removed by standard techniques while the remaining filtrate (comprising Li2S) can be recovered by evaporation ([0063]-[0064]).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to utilize the near infinite solubility ratio of NaCl relative to Li2S in polar solvent in the process of Li in order to effectively precipitate NaCl so that it can be removed by filtration and allow Li2S to be recovered, as taught by Wolden.
Regarding claims 42-43, Li in view of Otsuki teach the method of claim 1 and the claim further requires the second sulfide is Li2MgS2 (Claim 42) or Li2CaS2 (Claim 43) to which Li and Otsuki are silent.
Wolden teaches MSn nanocrystals are obtained through a salt metathesis reaction, where M includes Cr, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Hf, Nb, Ta, Sn, Zr, V, Mo, W, Ge, Ti, Al, Ca, Mg, Cd, Zn, and Si, and n is an integer of 1 to 4 ([0051]-[0052]). From the options presented by Wolden, which include Ca and Mg, a skilled artisan could readily arrive at the combinations of Li2MgS2 and Li2CaS2 as required by the instant claim.
Advantageously, the MSn salts are sparingly soluble in the reaction solutions that allow them to be separated from the solution ([0020]-[0021]).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to prepare MSn salts, where M comprises Mg and Ca, in the process of Li in order to provides MSn salts that are sparingly soluble in the reaction solutions that allow them to be separated from the solution, as taught by Wolden.
Claim 27 is rejected under 35 U.S.C. 103 as being unpatentable over Li et al. (CN103552990A English; cited in IDS dated 11/07/2024) in view of Otsuki et al. (JP6725876B2 English) and further in view of Wolden et al. (US20210261411A1) and Senga et al. (US20180162730A1; cited in IDS dated 04/14/2025), with evidentiary support for claim 1 provided by Basma et al. (J. Phys. Chem. B 2018, 122, 8963−8971).
Regarding claim 27, Li in view of Otsuki teach the method of claim 1, where Li teaches the lithium chloride is dissolved in the polar solvent, NMP, prior to adding sodium sulfhydrate, which is a solid measured in grams (Pg. 2, Embodiment 1). Li is silent regarding separately dissolving a first sulfide and the first alkali metal hydrosulfide in a polar solvent prior to reacting them together. Otsuki is also silent regarding these limitations.
Wolden teaches a method of making anhydrous metal sulfide nanocrystals that comprises mixing a first sulfide salt (Abstract; [0013]), comprising Na2S, K2S, Rb2S, Cs2S, Fr2S, (NH4)2S, P2S5, NiS, and combinations thereof ([0017]), with a first lithium salt selected from the group consisting of lithium carbonate (Li2CO3), lithium sulfate (Li2SO4), lithium sulfite (Li2SO3), lithium amide (LiNH2), lithium nitride (LiN3), lithium nitrate (LiNO3), lithium phosphate (Li3PO4), and combinations thereof ([0018]), to provide Li2S (i.e. a second sulfide) and/or other metal or metalloid sulfides (MSn) (i.e. a third sulfide), where MSn is selected from the group consisting Cr2S3 , MnS, ReS2 , FeS2 , RuS2 , OsS2 , CoS2 , RhS2 , IrS3 , NiS2 , PdS, PtS, HfS2 , NbS2 , TaS2 , GeS2 , SiS2 , TiS2 , SnS2 , MoS2 , ZrS2 , CdS, ZnS, VS2 , WS2 , Al2S3 , CaS, and MgS ([0019]-[0023]). Wolden teaches a first solution of Na2S in ethanol is prepared, while a second solution of LiCl is dissolved in ethanol, prior to combining stoichiometric amounts of the first and seconds solutions ([0063]). Wolden teaching preparing separate solutions of Na2S and LiCl
Advantageously, preparing solutions of LiCl and Na2S allows solvent mixtures in which Li2S (the desired product) is not soluble in, or sparingly soluble in, which aids its recovering during the reaction once it has separated ([0041]-[0044]).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to prepare solutions of Na2S and LiCl separately prior to combining them in the process of Li in order to effectively precipitate Li2S by using solvents it is sparingly soluble in, as taught by Wolden.
The claim further requires “the first alkali metal hydrosulfide is independently dissolved in polar solvent,” to which Li, Otsuki, and Wolden are silent.
Senga teaches a method of preparing a solid electrolyte comprising lithium sulfide that includes heating a mixture comprising lithium hydrosulfide and lithium halide in the presence of hydrogen sulfide (Abstract; [0044]). Senga teaches the lithium hydrosulfide and the lithium halide are separately dissolved prior to mixing the two ([0052]).
Advantageously, the solutions are easy to handle and can be readily mixed with other solutions while reducing the energy necessary for heating the solution containing lithium hydrosulfide and lithium halide ([0052]).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to dissolve the hydrosulfide salt in the process of Li in order to provide an easy-to-handle solution that can be readily mixed with other solutions while reducing the energy necessary for subsequent heating, as taught by Senga.
Claim 41 is rejected under 35 U.S.C. 103 as being unpatentable over Li et al. (CN103552990A English; cited in IDS dated 11/07/2024) in view of Otsuki et al. (JP6725876B2 English) and further in view of Shameem et al. (J Inorg. Organomet. Polym. 2018, 28, 671–678), with evidentiary support for claim 1 provided by Basma et al. (J. Phys. Chem. B 2018, 122, 8963−8971).
Regarding claim 41, Li in view of Otsuki teach the method of claim 1 and the claim further requires the second sulfide further comprises “LiNaS,” to which Li and Otsuki are silent.
Shameem teaches the direct synthesis of NaLiS (Abstract) where, advantageously, NaLiS displays an ionic conductivity that is six orders of magnitude higher than that of the micro-sized bulk Li2S (Abstract).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to produce NaLiS in the process of Li in order to provide a sulfide product NaLiS that displays a six orders-of-magnitude improvement on ionic conductivity relative to Li2S as taught by Shameem.
Claim 46 is rejected under 35 U.S.C. 103 as being unpatentable over Li et al. (CN103552990A English; cited in IDS dated 11/07/2024) in view of Otsuki et al. (JP6725876B2 English), with evidentiary support for claim 46 provided by Basma et al. (J. Phys. Chem. B 2018, 122, 8963−8971).
Regarding claim 46, Li teaches a method of preparing high-purity lithium sulfide comprising reacting lithium chloride (i.e. LiCl, a first alkali metal salt) with sodium or potassium sulfohydrate (i.e. NaHS, a first alkali metal hydrosulfide) in N-methyl pyrrolidone to produce a precipitate (i.e. NaCl, second alkali metal salt precipitate) that is filtered off to provide a solution of lithium sulfide (Li2S) in N-methyl pyrrolidone that has its solvent removed prior to provide the high-purity lithium sulfide (i.e. a second sulfide) (Abstract; Claims 1, 4, 5; Pg. 2, par. 3-13; Pg. 2-3, Embodiment 1). N-methyl pyrrolidone is a polar solvent, as evidenced by Basma who teaches N-methyl pyrrolidone is a strongly polar solvent (Pg. 8963, left col.).
The claim further requires “Na2S” is included in the reacting step of LiCl and NaHS and that the “NaHS is a NaHS hydrate having a water content from about 20% to about 75% by weight,” to which Li is silent.
Otsuki teaches a method of preparing anhydrous alkali metal sulfides that includes reacting a alkali metal sulfide with a hydrous alkali metal hydrosulfide, where the alkali metal sulfide can include compounds such as lithium, sodium, potassium, rubidium, and cesium sulfide while the hydrated alkali metal hydrosulfide can include hydrates of compounds such as lithium, sodium, potassium, rubidium, and cesium hydrosulfide, where the alkali metal hydrosulfide comprises 10-80% by mass while the remaining mass% is balanced with water from the hydrate and aqueous solution (Abstract; Title; Pg. 2, par. 11-12). Otsuki teaching the remaining mass of the hydrated alkali metal hydrosulfide is met with water effectively teaches a water mass% of about 20-90%, which overlaps the claimed range. Mass% and weight% are equivalent terms. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP 2144.05 (I). In the instant case, the range taught by Otsuki (10-90 mass% water in the alkali metal hydrosulfide) overlaps with the claimed range (about 20% to about 75% by weight water content). Therefore, the range in Otsuki renders obvious the claimed range.
Advantageously, providing an alkali metal sulfide such as lithium, sodium, potassium, rubidium, and cesium sulfide with an alkali metal hydrosulfide such as lithium, sodium, potassium, rubidium, and cesium hydrosulfide with a water content from 10-90 mass% provides an alkali metal sulfide product with fine-grains and high purity (Pg. 2, par. 2-6; Pg. 3, par. 7).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to use an alkali metal sulfide and a hydrated alkali metal hydrosulfide containing 10-90 mass% water in the process of Li in order to provide a high purity alkali metal sulfide product with fine-grains, as taught by Otsuki.
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Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Abraham et al. (US5833718); Abraham teaches a method of preparing sodium potassium sulfide comprising reacting an alkali metal hydrosulfide, e.g. sodium hydrosulfide (Abstract).
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/JORDAN W TAYLOR/Examiner, Art Unit 1738
/SALLY A MERKLING/SPE, Art Unit 1738
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