DETAILED ACTION
This Office Action is responsive to the November 4th, 2025 arguments and remarks (“Remarks”). The
text of those sections of Title 35, U.S. Code not included in this action can be found in a prior
Office 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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on November 4th, 2025 has been entered.
Response to Amendment
In response to the amendments received on November 4th, 2025:
Claims 1-4 and 6-21 are pending in the current application. Claims 1, 3-4, 7, 10-11, 13, 16-19, and 21 are amended. Claims 13-20 were previously withdrawn. Claim 5 was previously cancelled.
Claims 1 and 7 are amended to further limit the first salt to potassium nitrate and cesium nitrate, and to further limit the second salt to potassium phosphate and cesium phosphate.
Claim 3 is amended to specify at least one of the first and the second salt further comprising lithium nitrate.
Claim 4 is amended to adjust dependency from Claim 3 to Claim 1.
Claim 10 is amended to remove limitations describing lithium nitrate as included in the first salt and lithium phosphate included in the second salt.
Claim 11 is amended to describe concentrations of the first lithium salt and the second lithium salt.
Claim 21 is amended to clarify that at least one of the first salt and the second salt further comprises the disclosed concentrations of lithium nitrate and lithium phosphate.
Applicant’s amendment finds support in the disclosure including the originally filed claims and specification ([0009], [0013]). No new matter has been added.
Status of Claims
Claims 1-4, 6-12, and 21 stand rejected under 35 U.S.C. 103 as described below:
Claims 1-4, 6-12, and 21 are rejected under 35 U.S.C. 103 as being unpatentable over Du et al. (U.S. Pat. No. 20210020949 A1) (Cited in the IDS) in view of Guo et al. (C.N. Pat. No. 109103517 A) (Cited in the IDS). The rejections are withdrawn in view of the amendment.
Response to Arguments
Applicant’s arguments filed November 4th, 2025 have been fully considered as further described below:
Applicant presents arguments to Claim 1 and Claim 7 in which are based on the claims as amended. Therefore, applicant’s arguments with respect to Claims 1 and 7 have been considered but are moot because the new grounds of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Cited Prior Art
Previously Cited Du et al. (U.S. Pat. No. 20210020949 A1) (Cited in the IDS) (“Du et al.”)
Previously Cited Guo et al. (C.N. Pat. No. 109103517 A) (Cited in the IDS) (“Guo et al.”)
Sugimori et al. (U.S. Pat. No. 20190044179 A1) (“Sugimori et al.”)
Ryu et al. (U.S. Pat. No. 20170062829 A1) (“Ryu et al.”)
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.
Claims 1-4, 6-12, and 21 are rejected under 35 U.S.C. 103 as being unpatentable over Du et al. (U.S. Pat. No. 20210020949 A1) (Cited in the IDS) in view of Guo et al. (C.N. Pat. No. 109103517 A) (Cited in the IDS), and further in view of Sugimori et al. (U.S. Pat. No. 20190044179 A1) and Ryu et al. (U.S. Pat. No. 20170062829 A1).
Regarding Claim 1, Du et al. teaches an electrode in which can be an anode comprising a conductive anode material (electroactive material layer) (para. 46). An artificial SEI layer (protective layer) may be disposed on the anode or the surface of the electroactive material layer (para. 55). The protective layer is a flexible polymeric matrix (para. 135) formed by mixing a polymer, an artificial SEI forming salt such as a lithium salt (para. 36), and a solvent such as 1,3-dioxolane (para. 40) in which is equivalent to a polymerized 1,3-dioxolane matrix having salt dispersed therewithin. The artificial SEI forming salt is not limited to a lithium salt and can include other suitable salts and combinations thereof; the salt acts as a mechanical modulus enhance and lowers the interfacial resistance (para. 30).
Du et al. does not teach specific weight percentages of the polymerized 1,3-dioxolane and the one or more salts.
Guo et al. teaches a polymer protective layer comprising a polymerizable monomer, solvent, and one or more lithium salts in which the polymerizable monomer is a cyclic ether such as 1,3-dioxolane (para 10, 26, 29). The polymerization monomer is present in a volume fraction of 10% to 90%, preferably from 50% to 80% (para. 10) and the molar concentration of the lithium salt can range from 0.2 to 7 M (para. 29). Based on the provided volume fraction of the monomer, the molar concentration of the lithium salt, a total volume of 40 µl of a precursor solution (Example 1 in para. 51), and further obtaining estimated densities of the monomer/solvent from existing prior art available, the mass/weight percentage of the lithium salt/monomer can be obtained by one of ordinary skill in the art. (Mass of monomer/solvent = Volume Fraction x Volume (40 µl) x Density, Mass of salt = Concentration x Volume (40 µl) x Molar Mass). The individual weight percentages were calculated by dividing the mass of the monomer, solvent, or salt individually by the total mass of the monomer, solvent, and salt. It is within the level of one of ordinary skill in the art to convert volume fractions provided by Guo et al. into mass fractions in which conversion from volume to mass is not an inventive concept.
Constructed Table 1, reading results from left to right, shows results of performing the conversion using the limits of Guo et al. (For example, circled Line 1 shows results at a salt concentration of 1 M (mol/L), 50:50 monomer to solvent volume fraction, a monomer mass of 0.0212 g, a solvent mass of 0.023 g, with the bolded weight percentages of monomer, solvent, and salt totaling 100 across each row). The density of the solvent (1:1:1 EC/DEC/DMC of Example 1) and polymerizable 1,3-dioxolane are inherent physical properties in which are generally available in the field of endeavor. Although, the densities can vary based on the process conditions, only slight deviation is expected resulting in insignificant variation in the calculated weight percentages. As shown in table 1, a monomer volume fraction of 50 to 80% is approximately equivalent to a monomer weight ratio of 42 to 69% (1 M salt), lying inside the claimed range of 20 wt. % to less than or equal to 80 wt. %. A salt concentration of 1 M to 7M considering the parameters above provides an approximate equivalent weight percentage of salt (LiPF6) ranging from 12 to 50% (with a monomer ratio of 50 to 80%) (see Table 1), within and [AltContent: textbox (Table I)]
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overlapping the claimed range of 40 to 60 wt. %.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the protective layer of Du et al. by Guo et al. to include a volume fraction of polymerizable 1,3-dioxolane matrix of 50 to 80% with a 1 M to 7 M salt concentration, equivalent to 42 to 69 wt. % (1 M salt) or 24 to 40 wt.% (7 M salt), lying inside of the claimed range of 20 wt. % to less than or equal to 80 wt. %; and providing an approximate amount of salt of 12 to 50 wt. % from a 1 M to 7 M salt concentration, overlapping the claimed range of 40 wt.% to less than or equal to about 60 wt. % of the one or more salts. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. See In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990) (see MPEP § 2144.05, I). One of ordinary skill in the art would be motivated to perform the described modification to provide a protective layer for an electrode to solve the problem of dendrite formation, improving the cycle stability and battery safety, while comprising a simple preparation method with high scale and commercialization prospects (para. 37).
Du et al. does not teach the one or more salts comprising a first salt selected from the group consisting of: potassium nitrate (KNO3), cesium nitrate (CsNO3), and combinations thereof.
Ryu et al. teaches a protective layer comprising CsNO3 salt (para .56) disposed on an anode (para. 11). The cesium element has a relatively large atom size and thus causes a steric hindrance effect in the protective layer, suppressing growth of lithium dendrites on the surface of the anode (para. 50).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the protective layer of Du et al. to include CsNO3 salt as taught by Ryu et al. As Du et al. teaches the use of a combination of salts in which are not limited to the group recited (para. 30), it would be obvious to one of ordinary skill in the art to include CsNO3 as a first salt. The selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art. See In re Leshin, 125 USPQ 416 (CCPA 1960) (see MPEP § 2144.07). One of ordinary skill in the art would be motivated to select the salt disclosed by Ryu et al. (CsNO3) as Ryu et al. describes its suitability in a protective layer for an electrode with benefits of suppressing the growth of lithium dendrites on the electrode surface as described above.
Du et al. does not teach the one or more salts comprising a second salt selected from the group consisting of: potassium phosphate (K3PO4), cesium phosphate (Cs3PO4), and combinations thereof.
Sugimori et al. teaches a protective coating (layer) comprising potassium phosphate (a salt) formed on the surface of a negative electrode; the protective layer contributes to the suppression of gas generation (para. 31).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the protective layer of Du et al. to include potassium phosphate salt as disclosed by Sugimori et al. As Du et al. teaches the use of a combination of salts in which are not limited to the group recited (para. 30), it would be obvious to one of ordinary skill in the art to include potassium phosphate as a second salt. The selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art. See In re Leshin, 125 USPQ 416 (CCPA 1960) (see MPEP § 2144.07). One of ordinary skill in the art would be motivated to select the salt disclosed by Sugimori et al. (potassium phosphate) to provide a protective layer in which contributes to the suppression of gas generation.
Regarding Claim 2, Du et al. is modified by Guo et al., Sugimori et al., and Ryu et al. teaching all claim limitations as applied to Claim 1 above. Du et al. teaches the protective later having a Young’s (elastic) modulus of 1 MPa (0.001 GPa) to 10 GPa (para. 44), overlapping and within the claimed range of 0.01 GPa to 50 GPa. The protective layer has a thickness of at least 0.5 micrometers to 20 micrometers (para. 45), overlapping and within the claimed range of about 50 nm (0.05 micrometers) to 10 micrometers (see MPEP § 2144.05, I). It would have been obvious to one of ordinary skill in the art to apply the elastic modulus and thickness to the protective layer to provide an SEI layer with high mechanical strength, good flexibility, and improved coulombic efficiency (Du et al., para. 58).
Regarding Claim 3, Du et al. is modified by Guo et al., Sugimori et al., and Ryu et al. teaching all claim limitations as applied to Claim 1 above. Du et al. teaches the artificial SEI forming salts comprising lithium nitrate (LiNO3) or a combination of salts (para. 30, 36) in which it is obvious to one of ordinary skill in the art to include lithium nitrate within at least one of the first salt or second salt. As Du et al. teaches the use of a combination of salts in which are not limited to the group recited (para. 30), it would be obvious to use a plurality of salts within the protective layer formulation to achieve the benefits disclosed by the prior art; for example, one of ordinary skill in the art would find the teachings of Du et al. useful in providing a salt capable of SEI formation in which can prevent severe interface fluctuation and dendrite growth (Du et al., para. 58). Therefore, the use of a plurality and combination of salts is within the level of one of ordinary skill in the art.
Regarding Claim 4, Du et al. is modified by Guo et al., Sugimori et al., and Ryu et al. teaching all claim limitations as applied to Claim 1 above. Du et al. further teaches the salt comprising lithium hexafluorophosphate (LiPF6) (para. 36). It would be obvious to one of ordinary skill in the art to include the LiPF6 as a third salt based on Du et al. disclosing that a combination of salts can be used in the protective layer (para. 30). One of ordinary skill in the art would find the teachings of Du et al. useful in providing a salt capable of SEI formation in which can prevent severe interface fluctuation and dendrite growth (Du et al., para. 58).
Regarding Claim 6, Du et al. is modified by Guo et al., Sugimori et al., and Ryu et al. teaching all claim limitations as applied to Claim 1 above. Du et al. teaches the anode material (electroactive material layer) comprising a lithium metal (para. 47).
Regarding Claim 7, Du et al. teaches a lithium-ion electrochemical cell in which cycles lithium ions (para. 51). The electrochemical cell can include an anode (electrode), a cathode, and an electrolyte (separator) disposed between the anode and cathode (para. 68). An artificial SEI layer (protective layer) is formed on the surface of the anode in which is formed between the electrode and the separator electrolyte (para. 68). The protective layer is a flexible polymeric matrix (para. 135) formed by mixing a polymer, an artificial SEI forming salt such as a lithium salt (para. 36), and a solvent such as 1,3-dioxolane (cyclic ether) (para. 40) in which is equivalent to a polymerized matrix comprising a polymerized cyclic ether having salt dispersed therewithin. Further, the one or more salts can comprise a combination of lithium nitrate (LiNO3) and lithium phosphate (Li3PO4) (para. 36).
Du et al. does not teach specific weight percentages of the polymerized 1,3-dioxolane and the one or more salts.
Guo et al. teaches a polymer protective layer comprising a polymerizable monomer, solvent, and one or more lithium salts in which the polymerizable monomer is a cyclic ether such as 1,3-dioxolane (para 10, 26, 29). The polymerization monomer is present in a volume fraction of 10% to 90%, preferably from 50% to 80% (para. 10) and the molar concentration of the lithium salt can range from 0.2 to 7 M (para. 29). Based on the provided volume fraction of the monomer, the molar concentration of the lithium salt, a total volume of 40 µl of a precursor solution (Example 1 in para. 51), and further obtaining estimated densities of the monomer/solvent from existing prior art available, the mass/weight percentage of the lithium salt/monomer can be obtained by one of ordinary skill in the art. It is within the level of one of ordinary skill in the art to convert volume fractions provided by Guo et al. into mass fractions in which conversion from volume to mass is not an inventive concept.
Constructed Table 1, reading results from left to right, shows results of performing the conversion using the limits of Guo et al. (For example, circled Line 1 shows results at a salt concentration of 1 M (mol/L), 50:50 monomer to solvent volume fraction, a monomer mass of 0.0212 g, a solvent mass of 0.023 g, with the bolded weight percentages of monomer, solvent, and salt totaling 100 across each row). The density of the solvent (1:1:1 EC/DEC/DMC of Example 1) and polymerizable 1,3-dioxolane are inherent physical properties in which are generally available in the field of endeavor. Although, the densities can vary based on the process conditions, only slight deviation is expected resulting in insignificant variation in the calculated weight percentages. As shown in table 1, a monomer volume fraction of 50 to 80% is approximately equivalent to a monomer weight ratio of 42 to 69% (1 M salt), lying inside the claimed range of 20 wt. % to less than or equal to 80 wt. %. A salt concentration of 1 M to 7M considering the parameters above provides an approximate equivalent weight percentage of salt (LiPF6) ranging from 12 to 50% (with a monomer ratio of 50 to 80%) (see Table 1), within and overlapping the claimed range of 40 to 60 wt. %.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the protective layer of Du et al. by Guo et al. to include a volume fraction of polymerizable 1,3-dioxolane matrix of 50 to 80% with a 1 M to 7 M salt concentration, equivalent to 42 to 69 wt. % (1 M salt) or 24 to 40 wt.% (7 M salt), lying inside of the claimed range of 20 wt. % to less than or equal to 80 wt. %; and providing an approximate amount of salt of 12 to 50 wt. % from a 1 M to 7 M salt concentration, overlapping the claimed range of 40 wt.% to less than or equal to about 60 wt. % of the one or more salts (see MPEP § 2144.05, I). One of ordinary skill in the art would be motivated to perform the described modification to provide a protective layer for an electrode to solve the problem of dendrite formation, improving the cycle stability and battery safety, while comprising a simple preparation method with high scale and commercialization prospects (Guo et al., para. 37).
Du et al. does not teach the one or more salts comprising a first salt selected from the group consisting of: potassium nitrate (KNO3), cesium nitrate (CsNO3), and combinations thereof.
Ryu et al. teaches a protective layer comprising CsNO3 salt (para .56) disposed on an anode (para. 11). The cesium element has a relatively large atom size and thus causes a steric hindrance effect in the protective layer, suppressing growth of lithium dendrites on the surface of the anode (para. 50).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the protective layer of Du et al. to include CsNO3 salt as taught by Ryu et al. As Du et al. teaches the use of a combination of salts in which are not limited to the group recited (para. 30), it would be obvious to one of ordinary skill in the art to include CsNO3 as a first salt. The selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art. See In re Leshin, 125 USPQ 416 (CCPA 1960) (see MPEP § 2144.07). One of ordinary skill in the art would be motivated to select the salt disclosed by Ryu et al. (CsNO3) as Ryu et al. describes its suitability in a protective layer for an electrode with benefits of suppressing the growth of lithium dendrites on the electrode surface as described above.
Du et al. does not teach the one or more salts comprising a second salt selected from the group consisting of: potassium phosphate (K3PO4), cesium phosphate (Cs3PO4), and combinations thereof.
Sugimori et al. teaches a protective coating (layer) comprising potassium phosphate (a salt) formed on the surface of a negative electrode; the protective layer contributes to the suppression of gas generation (para. 31).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the protective layer of Du et al. to include potassium phosphate salt as disclosed by Sugimori et al. As Du et al. teaches the use of a combination of salts in which are not limited to the group recited (para. 30), it would be obvious to one of ordinary skill in the art to include potassium phosphate as a second salt. The selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art. See In re Leshin, 125 USPQ 416 (CCPA 1960) (see MPEP § 2144.07). One of ordinary skill in the art would be motivated to select the salt disclosed by Sugimori et al. (potassium phosphate) to provide a protective layer in which contributes to the suppression of gas generation.
Regarding Claim 8, Du et al. is modified by Guo et al., Sugimori et al., and Ryu et al. teaching all claim limitations as applied to Claim 7 above. As applied to Claim 7, Du et al. teaches that the polymerized cyclic ether can comprise 1,3-dioxolane (DOL) (para. 40).
Regarding Claim 9, Du et al. is modified by Guo et al., Sugimori et al., and Ryu et al. teaching all claim limitations as applied to Claim 7 above. Du et al. teaches the polymerized cyclic ether comprising tetrahydrofuran (THF) in which THF is a polymerizable cyclic ether. The protective layer is a flexible polymeric matrix (para. 135) formed by mixing a polymer, an artificial SEI forming salt such as a lithium salt (para. 36), and a solvent such as THF (para. 40) in which is equivalent to a polymerized THF (cyclic ether) matrix.
Regarding Claim 10, Du et al. is modified by Guo et al., Sugimori et al., and Ryu et al. teaching all claim limitations as applied to Claim 7 above. Du et al. further teaches the artificial SEI forming salt can comprise lithium hexafluorophosphate (LiPF6) (para. 36). As Du et al. teaches the use of a combination of salts in which are not limited to the group recited (para. 30), it would be obvious to one of ordinary skill in the art to further include LiPF6 as a third salt. The selection of a known material based on its suitability for its intended use supported a prima facie obviousness determination in Sinclair & Carroll Co. v. lnterchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945). One of ordinary skill in the art would be motivated to select the salts described based on their suitability for forming the artificial SEI and Du et al. suggests a combination. One of ordinary skill in the art would find the teachings of Du et al. useful in providing a salt capable of SEI formation in which can prevent severe interface fluctuation and dendrite growth (Du et al., para. 58).
Regarding Claim 11, Du et al. is modified by Guo et al., Sugimori et al., and Ryu et al. teaching all limitations as applied to Claim 10 above. As applied to above, Du et al. teaches a combination of salts in which are not limited to the recited compounds (para. 30). Therefore, it would be obvious to select a combination of salts comprising a first salt, second salt, and third salt based on the benefits disclosed by the prior art of utilizing a particular salt.
Du et al. does not teach specific weight percentages of the one or more salts.
Guo et al. teaches a polymer protective layer comprising a polymerizable monomer, solvent, and one or more lithium salts. The polymerization monomer is present in a volume fraction of 10% to 90%, preferably from 50% to 80% (para. 10) and the molar concentration of the lithium salt can range from 0.2 to 7 M (para. 29). Based on the provided volume fraction of the monomer, the molar concentration of the lithium salt, a total volume of 40 µl of a precursor solution (Example 1 in para. 51), and further obtaining estimated densities of the monomer and solvent from existing prior art available, the mass/weight percentage of the lithium salt/monomer can be obtained by one of ordinary skill in the art.
Table 1, as described above, shows results of performing the conversion using the limits of Guo et al. The density of the solvent (1:1:1 EC/DEC/DMC of Example 1) and polymerizable 1,3, dioxolane are inherent physical properties in which are generally available in the field of endeavor. Although, the densities can vary based on the process conditions, only slight deviation is expected resulting in insignificant variation in the calculated weight percentages. A salt concentration of 1 M to 7M considering the parameters above provides an approximate equivalent weight percentage of salt (LiPF6) ranging from 12 to 50% (with a monomer ratio of 50 to 80%) (see Table 1). It is within the level of one of ordinary skill in the art to convert volume fractions provided by Guo et al. into mass fractions in which conversion from volume to mass is not an inventive concept.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the protective layer of Du et al. by Guo et al. to include a volume fraction of polymerizable 1,3-dioxolane matrix of 50 to 80% providing an approximate weight percentage of salt of 12 to 50% from a 1 M to 7 M salt concentration. Performing the modification provides an amount of 12 to 50 wt.% of salt in which can be applied to the combination of salts as modified by the prior art, overlapping or within the claimed range of 5 to 30 wt.% of a first salt, 20 to 80 wt.% of a second salt, and 20-30 wt.% of the third salt (see MPEP § 2144.05, I). One of ordinary skill in the art would be motivated to perform the described modification to provide a protective layer for an electrode to solve the problem of dendrite formation, improving the cycle stability and battery safety, while comprising a simple preparation method with high scale and commercialization prospects (Guo et al., para. 37).
Regarding Claim 12, Du et al. is modified by Guo et al., Sugimori et al., and Ryu et al. teaching all claim limitations as applied to Claim 7 above. Du et al. teaches the protective later having a Young’s (elastic) modulus of 1 MPa (0.001 GPa) to 10 GPa (para. 44), overlapping and within the claimed range of 0.01 GPa to 50 GPa. The protective later has a thickness of at least 0.5 micrometers to 20 micrometers, overlapping and within the claimed range of 50 nm (0.05 micrometers) to 10 micrometers (see MPEP § 2144.05, I). It would have been obvious to one of ordinary skill in the art to apply the elastic modulus and thickness to the protective layer to provide an SEI layer with high mechanical strength, good flexibility, and improved coulombic efficiency (Du et al., para. 58).
Regarding Claim 21, Du et al. is modified by Guo et al., Sugimori et al., and Ryu et al. teaching all claim limitations as applied to Claim 1 above. As Du et al. teaches the use of a combination of salts in which are not limited to the group recited (para. 30), it would be obvious to use a plurality and combination of salts within the protective layer formulation to achieve the benefits disclosed by the prior art; Du et al. teaches the artificial SEI forming salts comprising lithium nitrate (LiNO3) and lithium phosphate (Li3PO4) or a combination thereof (para. 36) in which it is obvious to one of ordinary skill in the art to include lithium nitrate and lithium phosphate in combination with the first salt or the second salt. Du et al. further teaches the salt comprising a lithium hexafluorophosphate (LiPF6) (para. 36) in which it would be obvious to one of ordinary skill in the art to include as a third salt. One of ordinary skill in the art would be motivated to use a plurality of salts as Du et al. discloses their ability to lower the interfacial resistance (para. 30).
The selection of a known material based on its suitability for its intended use supported a prima facie obviousness determination in Sinclair & Carroll Co. v. lnterchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945). One of ordinary skill in the art would be motivated to select the salts described based on their suitability for forming the artificial SEI and Du et al. suggests a combination. One of ordinary skill in the art would find the teachings of Du et al. useful in providing a salt capable of SEI formation in which can prevent severe interface fluctuation and dendrite growth (Du et al., para. 58).
Du et al. does not teach specific weight percentages of the one or more salts.
Guo et al. teaches a polymer protective layer comprising a polymerizable monomer, solvent, and one or more lithium salts. The polymerization monomer is present in a volume fraction of 10% to 90%, preferably from 50% to 80% (para. 10) and the molar concentration of the lithium salt can range from 0.2 to 7 M (para. 29). Based on the provided volume fraction of the monomer, the molar concentration of the lithium salt, a total volume of 40 µl of a precursor solution (Example 1 in para. 51), and further obtaining estimated densities of the monomer and solvent from existing prior art available, the mass/weight percentage of the lithium salt/monomer can be obtained by one of ordinary skill in the art.
Table 1, as described above, shows results of performing the conversion using the limits of Guo et al. The density of the solvent (1:1:1 EC/DEC/DMC of Example 1) and polymerizable 1,3, dioxolane are inherent physical properties in which are generally available in the field of endeavor. Although, the densities can vary based on the process conditions, only slight deviation is expected resulting in insignificant variation in the calculated weight percentages. A salt concentration of 1 M to 7M considering the parameters above provides an approximate equivalent weight percentage of salts (LiPF6) ranging from 12 to 50% (with a monomer ratio of 50 to 80%) (see Table 1). It is within the level of one of ordinary skill in the art to convert volume fractions provided by Guo et al. into mass fractions in which conversion from volume to mass is not an inventive concept.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the protective layer of Du et al. by Guo et al. to include a volume fraction of polymerizable 1,3-dioxolane matrix of 50 to 80% providing an approximate weight percentage of salt of 12 to 50% from a 1 M to 7 M salt concentration. Performing the modification provides an amount of 12 to 50 wt.% of salt, overlapping or within the claimed range of 5 to 30 wt.% of lithium nitrate, 20 to 80 wt.% of lithium phosphate, and 20-30 wt.% of lithium hexafluorophosphate (see MPEP § 2144.05, I) in which can be applied to the combination of salts (at least one of the first salt and the second salt) of Du et al. as modified by Sugimori et al. and Ryu et al. One of ordinary skill in the art would be motivated to perform the described modification to provide a protective layer for an electrode to solve the problem of dendrite formation, improving the cycle stability and battery safety, while comprising a simple preparation method with high scale and commercialization prospects (Guo et al., para. 37).
Conclusion
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/C.R.D./Examiner, Art Unit 1729
/ULA C RUDDOCK/Supervisory Patent Examiner, Art Unit 1729