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 and Claim Status
The amendment filed 2 February 2026 has been entered. Applicant’s amendments to the claims have overcome each and every objection set forth in the Office Action mailed 1 October 2025. Claims 3, 4, 6, 11, 16, 17, 22–24, and 26 are canceled. Claims 1, 2, 5, 7–10, 12–15, 18–21, and 25 are pending in the application.
Claim Objections
Claim 15 is objected to because “the electrolyte” in line 10 should read “the lithium-containing electrolyte”. Appropriate correction is required.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1, 5, 7, 15, and 21 are rejected under 35 U.S.C. 103 as being unpatentable over Cao et al. (US 2020/0161706 A1) in view of Chen et al. (“Toward wide-temperature electrolyte for lithium-ion batteries”), and further in view of Kim et al. (US 2022/0131192 A1).
Regarding Claims 1 and 15, Cao discloses an electrolyte (see localized superconcentrated electrolyte, [0143], FIG. 2) for a lithium-containing battery cell (see rechargeable battery 100, [0169]–[0170], FIG. 4A), the electrolyte comprising:
a solvent comprising at least one non-carbonate-containing ester compound (see solvent A, [0145]; note that solvent A is disclosed in [0148] to include ester solvents, e.g. aliphatic ester solvents);
one or more lithium salts ([0147]); and
a diluent ([0143]) comprising a fluorinated organic compound (see fluorinated orthoformate, [0155]).
Cao further discloses ([0146]) wherein the lithium salts have a concentration of 0.1 mols/liter to 30 mols/liter in the electrolyte, which overlaps with the claimed range of greater than 2.02 mols/liter. Note that 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).
Cao discloses ([0142]) that an increased salt concentration in the electrolyte can provide the added advantages of fewer or no free solvent molecules not associated with a lithium cation in the electrolyte and therefore increased coulombic efficiency, formation of a stabilized solid electrolyte interphase layer, and increased cycling stability of the lithium-containing battery cell (100). However, Cao also discloses ([0142]) that excessively increasing the lithium salt concentration without tempering of negative effects with a diluent can also lead to increased flammability, high material cost, high viscosity, and/or poor wetting of battery separators and/or cathodes. Cao is analogous to the claimed invention as it is in the same field of secondary batteries capable of cycling lithium.
A result-effective variable is a variable which achieves a recognized result. The determination of the optimum or workable ranges of a result-effective variable is routine experimentation and therefore obvious (MPEP § 2144.05.II). In the instant case, the concentration of lithium salts in the electrolyte is a variable that achieves the recognized results of affecting the coulombic efficiency, formation of a stabilized solid electrolyte interphase layer, cycling stability of the lithium-containing battery cell, flammability, material cost, viscosity, and wetting of battery separators and cathodes, thus making the concentration of lithium salts in the electrolyte a result-effective variable. Therefore, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention, in addition to the prima facie case of obviousness established above, to modify the lithium salt concentration of the electrolyte of Cao to lie within the range of greater than 2.02 mols/liter via routine experimentation, for the purpose of achieving an electrolyte with suitable coulombic efficiency, formation of a stabilized solid electrolyte interphase layer, cycling stability of the lithium-containing battery cell, flammability, material cost, viscosity, and wetting of battery separators and cathodes.
Cao does not explicitly disclose wherein the at least one non-carbonate-containing ester compound comprises butyl propionate, but does disclose ([0148]) that the compound can comprise aliphatic esters such as methyl butyrate and ethyl propionate.
Chen teaches electrolytes for lithium-containing battery cells (see LIBs electrolytes, p. 4 ¶ “The low-temperature performance…”). Chen teaches (p. 5 ¶ “Linear carboxylates include…”) that a non-carbonate-containing ester compound (see linear carboxylates; note that the linear carboxylates taught by Chen in p. 5 ¶ “Linear carboxylates include…” and FIG. 5 are all aliphatic esters), such as methyl butyrate (see FIG. 5D), ethyl propionate (see FIG. 5F), and butyl propionate (see FIG. 5N), have low freezing points, boiling points, and viscosities, which are solvent properties that enhance the low-temperature characteristics of an electrolyte.
Chen is analogous to the claimed invention as it is in the same field of secondary batteries capable of cycling lithium. It would therefore have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the electrolyte of modified Cao such that the solvent comprising at least one non-carbonate-containing ester compound comprises butyl propionate, because: (1) Chen teaches that butyl propionate is of the same genus (i.e. aliphatic esters) as the examples of suitable solvents listed by Cao and therefore it would be expected to exhibit similar properties, and (2) Chen teaches that non-carbonate-containing ester compounds such as butyl propionate have low freezing points, boiling points, and viscosities, which are solvent properties that enhance the low-temperature characteristics of an electrolyte.
Modified Cao does not explicitly disclose wherein the lithium-containing electrolyte is characterized by a viscosity of less than or about 10 cP at 23 °C (Claim 15), or more narrowly less than or about 5 cP at 23 °C (Claim 1).
Kim teaches an electrolyte (see non-aqueous electrolyte solution, [0037]) for a lithium-containing battery cell (see lithium secondary battery, [0037]), the electrolyte comprising a solvent (see organic solvent, [0038]) comprising at least one non-carbonate-containing ester compound ([0053]), and one or more lithium salts ([0038], [0049]) wherein the lithium salts have a concentration of 0.1 to 3 M ([0051]). Kim ([0051]) teaches that increasing the electrolyte viscosity can reduce the lithium ion-transfer effect and wetting of the electrolyte.
A result-effective variable is a variable which achieves a recognized result. The determination of the optimum or workable ranges of a result-effective variable is routine experimentation and therefore obvious (MPEP § 2144.05.II). In the instant case, electrolyte viscosity is a variable that achieves the recognized result of affecting the lithium ion-transfer effect and wetting of the electrolyte, as taught by Kim, thus making electrolyte viscosity a result-effective variable. Therefore, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the (lithium-containing) electrolyte of modified Cao such that the (lithium-containing) electrolyte is characterized by a viscosity of less than or about 10 cP at 23 °C, or more narrowly, less than or about 5 cP at 23 °C, via routine experimentation, for the purpose of achieving an electrolyte with suitable lithium ion-transfer effect and wetting.
Further regarding Claim 15, Cao further discloses a lithium-containing battery cell (see rechargeable battery 100, [0169]–[0170], FIG. 4A) comprising:
a positive electrode (see cathode 120, [0170], FIG. 4A);
a negative electrode (see anode 140, [0170], FIG. 4A); and
a lithium-containing electrolyte as set forth above (note that the electrolyte above is considered lithium-containing as it comprises one or more lithium salts).
Regarding Claim 5, modified Cao discloses the electrolyte as set forth above. Cao further discloses ([0147]) wherein the one or more lithium salts comprise one or more of LiPF6, LiAsF6, LiBF4, LiClO4, LiCF3SO3, LiN(CF3SO2)2 (see LiTFSI), LiN(C2F5SO2)2 (see LiBETI), and LiN(SO2F)2 (see LiFSI).
Regarding Claim 7, modified Cao discloses the electrolyte as set forth above. Cao further discloses wherein the diluent represents about 17 to 83 vol. % of the electrolyte, by teaching ([0162]) that a volumetric ratio of the solvent to the diluent (L solvent/L diluent) in the electrolyte is within a range of from 0.2 to 5 (as an example calculation: in the case of the value 0.2, the volumetric ratio of the solvent to the diluent would be 0.2 L solvent to 1 L diluent, for a total volume of 1.2 L; 1 L diluent in 1.2 L total volume would result in an electrolyte that is 83 vol. % diluent, i.e. 1 L diluent [Symbol font/0xB8] 1.2 L total × 100% = approx. 83 vol. %).
Regarding Claim 21, modified Cao discloses the electrolyte of Claim 1. Cao discloses wherein the electrolyte comprises 0 wt. % of carbonate-containing compounds, as Cao does not require carbonate compounds be included in the electrolyte (note that [0148] discloses carbonate solvents as one option amongst a list of other types of electrolyte solvents which can be used; note also that [0166] discloses carbonate compounds as possible bridge solvents, but does not require them and also lists non-carbonate options such as acetonitrile).
Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over Cao et al. (US 2020/0161706 A1) in view of Chen et al. (“Toward wide-temperature electrolyte for lithium-ion batteries”), and further in view of Kim et al. (US 2022/0131192 A1), as applied to Claims 1, 5, 7, 15, and 21 above, as evidenced by Seely (“Crystallization of Sodium Acetate from a Supersaturated Solution”).
Regarding Claim 2, modified Cao discloses the electrolyte as set forth above, but does not explicitly disclose wherein the one or more lithium salts are characterized by a supersaturated concentration in the solvent.
As set forth above, Cao teaches ([0142]) that an increased salt concentration in the electrolyte can provide the added advantage of fewer or no free solvent molecules not associated with a lithium cation in the electrolyte and therefore increased coulombic efficiency, formation of a stabilized solid electrolyte interphase layer, and increased cycling stability of the lithium-containing battery cell (100). Further, it is well known to one of ordinary skill in the art that a supersaturated concentration of a salt in a solvent can be achieved by forming a solution by dissolving salt in a solvent at an elevated temperature nearly to the point of saturation at the elevated temperature, and then cooling the solution back to room temperature, as evidenced by Seely (¶ “An aqueous solution…”).
KSR Rationale D (MPEP § 2141) states that it is obvious to apply a “known technique to a known device (method, or product) ready for improvement to yield predictable results”. It therefore would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to apply the known technique of reaching supersaturation of a salt in a solvent by forming a solution by dissolving a salt in a solvent at an elevated temperature nearly to the point of saturation at the elevated temperature, and then cooling the solution back to room temperature, to the electrolyte of modified Cao, to yield the predictable result of an electrolyte wherein the lithium salts are characterized by a supersaturated concentration in the solvent, i.e. a maximally high concentration of salt in the electrolyte, for the purpose of ensuring that there are fewer or no free solvent molecules not associated with a lithium cation in the electrolyte to increase coulombic efficiency, form a stabilized solid electrolyte interphase layer, and increase cycling stability of the lithium-containing battery cell.
Claims 8, 10, 12, 14, 18, and 25 are rejected under 35 U.S.C. 103 as being unpatentable over Cao et al. (US 2020/0161706 A1) in view of Chen et al. (“Toward wide-temperature electrolyte for lithium-ion batteries”), further in view of Kim et al. (US 2022/0131192 A1), and further in view of Park et al. (US 2023/0093801 A1).
Regarding Claims 8 and 18, modified Cao discloses the electrolyte and lithium-containing battery cell as set forth above. Cao further discloses wherein the electrolyte further comprises a phosphorous-containing additive (see flame-retardant compounds include… phosphorous containing compounds, [0149]), but does not disclose wherein the phosphorous-containing additive represents less than or about 2 wt. % of the (lithium-containing) electrolyte. Instead, Cao teaches ([0149]) wherein the electrolyte may include at least 5 wt. % of the phosphorous-containing additive, but also that the amount of the phosphorous-containing additive should be sufficient to render the electrolyte flame-retarded or non-flammable, and that the amount required to achieve this depends on the solvent chosen as well as the amount.
Park discloses an electrolyte (see electrolyte solution, [0054]) for a lithium-containing battery cell (see rechargeable lithium battery 100, [0053]), the electrolyte comprising a solvent comprising at least one non-carbonate-containing ester compound (see non-aqueous organic solvent, [0055], [0079]–[0080]), one or more lithium salts ([0055]); and a diluent comprising a fluorinated organic compound (see aromatic hydrocarbon-based organic solvent, [0086], examples of which include fluorinated organic compounds, [0089]). Park discloses wherein the electrolyte further comprises a phosphorous-containing additive that represents less than or about 2 wt. % of the electrolyte, by teaching that the electrolyte comprises a phosphorous-containing additive (see compound represented by Chemical Formula 1, [0055]–[0059]) and that the phosphorous-containing additive may be included in an amount of greater than about 0.2 parts by weight and less than about 2.0 parts by weight of the electrolyte ([0070]; i.e. greater than about 0.2 wt. % and less than about 2 wt. % of the electrolyte). Park teaches ([0060]–[0061]) that the phosphorous-containing additive has suitable or high high-temperature stability on the surface of the negative electrode, forms a solid electrolyte interface (SEI) with suitable or excellent ion conductivity, and suppresses a side reaction of LiPF6 to reduce the gas generation caused by a decomposition reaction of the electrolyte solution during high-temperature storage, greatly reducing the defect rate. Further, Park teaches ([0071]) that when the phosphorous-containing additive is included in an amount of greater than 0.2 wt. % and less than about 2 wt. % of the electrolyte, the lithium-containing battery cell (100) has improved storage characteristics at a high temperature and improved cycle-life characteristics. Thus, one of ordinary skill in the art will understand that the phosphorous-containing additives of Park render the electrolyte flame-retarded even in amounts of greater than 0.2 wt. % and less than about 2 wt. % of the electrolyte (in contrast to the higher range disclosed by Cao of at least 5 wt. %), as it is well-known in the field that decreasing the defect rate as described by Park will in turn decrease the associated risk of fire and explosion.
Park is analogous to the claimed invention as it is in the same field of secondary batteries capable of cycling lithium. It therefore would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the (lithium-containing) electrolyte of modified Cao such that it further comprises a phosphorous-containing additive that represents less than or about 2 wt.% of the electrolyte, as taught by Park, because the phosphorous-containing additive has suitable or high high-temperature stability on the surface of the negative electrode, forms an SEI with suitable or excellent ion conductivity, and suppresses a side reaction of LiPF6 to reduce the gas generation caused by a decomposition reaction of the electrolyte solution during high-temperature storage, greatly reducing the defect rate, and its inclusion in an amount of less than or about 2 wt. % of the electrolyte would provide the lithium-containing battery cell with improved storage characteristics at high temperature and improved cycle-life characteristics.
Regarding Claim 10, Cao discloses an electrolyte (see localized superconcentrated electrolyte, [0143], FIG. 2) for a lithium-containing battery cell (see rechargeable battery 100, [0169]–[0170], FIG. 4A), the electrolyte comprising:
a solvent comprising at least one non-carbonate-containing ester compound (see solvent A, [0145]; note that solvent A is disclosed in [0148] to include ester solvents, e.g. aliphatic ester solvents);
one or more lithium salts ([0147]); and
a diluent ([0143]) comprising a fluorinated organic compound (see fluorinated orthoformate, [0155]); and
a phosphorous-containing additive ([0149]).
Cao further discloses ([0146]) wherein the lithium salts have a concentration of 0.1 mols/liter to 30 mols/liter in the electrolyte, which overlaps with the claimed range of greater than 2.02 mols/liter. Note that 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).
Cao discloses ([0142]) that an increased salt concentration in the electrolyte can provide the added advantages of fewer or no free solvent molecules not associated with a lithium cation in the electrolyte and therefore increased coulombic efficiency, formation of a stabilized solid electrolyte interphase layer, and increased cycling stability of the lithium-containing battery cell (100). However, Cao also discloses ([0142]) that excessively increasing the lithium salt concentration without tempering of negative effects with a diluent can also lead to increased flammability, high material cost, high viscosity, and/or poor wetting of battery separators and/or cathodes. Cao is analogous to the claimed invention as it is in the same field of secondary batteries capable of cycling lithium.
A result-effective variable is a variable which achieves a recognized result. The determination of the optimum or workable ranges of a result-effective variable is routine experimentation and therefore obvious (MPEP § 2144.05.II). In the instant case, the concentration of lithium salts in the electrolyte is a variable that achieves the recognized results of affecting the coulombic efficiency, formation of a stabilized solid electrolyte interphase layer, cycling stability of the lithium-containing battery cell, flammability, material cost, viscosity, and wetting of battery separators and cathodes, thus making the concentration of lithium salts in the electrolyte a result-effective variable. Therefore, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention, in addition to the prima facie case of obviousness established above, to modify the lithium salt concentration of the electrolyte of Cao to lie within the range of greater than 2.02 mols/liter via routine experimentation, for the purpose of achieving an electrolyte with suitable coulombic efficiency, formation of a stabilized solid electrolyte interphase layer, cycling stability of the lithium-containing battery cell, flammability, material cost, viscosity, and wetting of battery separators and cathodes.
Cao does not explicitly disclose wherein the at least one non-carbonate-containing ester compound comprises propyl butyrate, but does disclose ([0148]), as set forth above, that the compound can comprise aliphatic esters such as methyl butyrate and ethyl propionate.
Chen teaches electrolytes for lithium-containing battery cells (see LIBs electrolytes, p. 4 ¶ “The low-temperature performance…”). Chen teaches (p. 5 ¶ “Linear carboxylates include…”) that a non-carbonate-containing ester compound (see linear carboxylates; note that the linear carboxylates taught by Chen in p. 5 ¶ “Linear carboxylates include…” and FIG. 5 are all aliphatic esters), such as methyl butyrate (see FIG. 5D), ethyl propionate (see FIG. 5F), and propyl butyrate (see FIG. 5J), have low freezing points, boiling points, and viscosities, which are solvent properties that enhance the low-temperature characteristics of an electrolyte.
Chen is analogous to the claimed invention as it is in the same field of secondary batteries capable of cycling lithium. It would therefore have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the electrolyte of modified Cao such that the solvent comprising at least one non-carbonate-containing ester compound comprises propyl butyrate, because: (1) Chen teaches that propyl butyrate is of the same genus (i.e. aliphatic esters) as the examples of suitable solvents listed by Cao and therefore it would be expected to exhibit similar properties, and (2) Chen teaches that non-carbonate-containing ester compounds such as propyl butyrate have low freezing points, boiling points, and viscosities, which are solvent properties that enhance the low-temperature characteristics of an electrolyte.
Cao does not disclose wherein the phosphorous-containing additive represents less than or about 2 wt. % of the electrolyte, and instead discloses ([0146]) wherein the electrolyte may include at least 5 wt. % of the phosphorous-containing additive, but also that the amount of the phosphorous-containing additive should be sufficient to render the electrolyte flame-retarded or non-flammable, and that the amount required to achieve this depends on the solvent chosen as well as the amount.
Park discloses an electrolyte (see electrolyte solution, [0054]) for a lithium-containing battery cell (see rechargeable lithium battery 100, [0053]), the electrolyte comprising a solvent comprising at least one non-carbonate-containing ester compound (see non-aqueous organic solvent, [0055], [0079]–[0080]), one or more lithium salts [0055]); and a diluent comprising a fluorinated organic compound (see aromatic hydrocarbon-based organic solvent, [0086], examples of which include fluorinated organic compounds, [0089]). Park discloses wherein the electrolyte further comprises a phosphorous-containing additive that represents less than or about 2 wt. % of the electrolyte, by teaching that the electrolyte comprises a phosphorous-containing additive (see compound represented by Chemical Formula 1, [0055]–[0059]) and that the phosphorous-containing additive may be included in an amount of greater than about 0.2 parts by weight and less than about 2.0 parts by weight of the electrolyte ([0070]; i.e. greater than about 0.2 wt. % and less than about 2 wt. % of the electrolyte). Park teaches ([0060]–[0061]) that the phosphorous-containing additive has suitable or high high-temperature stability on the surface of the negative electrode, forms a solid electrolyte interface (SEI) with suitable or excellent ion conductivity, and suppresses a side reaction of LiPF6 to reduce the gas generation caused by a decomposition reaction of the electrolyte solution during high-temperature storage, greatly reducing the defect rate. Further, Park teaches ([0071]) that when the phosphorous-containing additive is included in an amount of greater than 0.2 wt. % and less than about 2 wt. % of the electrolyte, the lithium-containing battery cell has improved storage characteristics at a high temperature and improved cycle-life characteristics. Thus, one of ordinary skill in the art will understand that the phosphorous-containing additives of Park render the electrolyte flame-retarded even in amounts of greater than 0.2 wt. % and less than about 2 wt. % of the electrolyte (in contrast to the higher range disclosed by Cao of at least 5 wt. %), as it is well-known in the field that decreasing the defect rate as described by Park will in turn decrease the associated risk of fire and explosion.
Park is analogous to the claimed invention as it is in the same field of secondary batteries capable of cycling lithium. It therefore would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the electrolyte of modified Cao such that it comprises a phosphorous-containing additive that represents less than or about 2 wt.% of the electrolyte, as taught by Park, because the phosphorous-containing additive has suitable or high high-temperature stability on the surface of the negative electrode, forms an SEI with suitable or excellent ion conductivity, and suppresses a side reaction of LiPF6 to reduce the gas generation caused by a decomposition reaction of the electrolyte solution during high-temperature storage, and its inclusion in an amount of less than or about 2 wt. % of the electrolyte would provide the lithium-containing battery cell with improved storage characteristics at high temperature and improved cycle-life characteristics.
Cao does not explicitly disclose wherein the electrolyte is characterized by a viscosity of less than or about 10 cP at 23 °C.
Kim teaches an electrolyte (see non-aqueous electrolyte solution, [0037]) for a lithium-containing battery cell (see lithium secondary battery, [0037]), the electrolyte comprising a solvent (see organic solvent, [0038]) comprising at least one non-carbonate-containing ester compound ([0053]), and one or more lithium salts ([0038], [0049]) wherein the lithium salts have a concentration of 0.1 to 3 M ([0051]). Kim ([0051]) teaches that increasing the electrolyte viscosity can reduce the lithium ion-transfer effect and wetting of the electrolyte.
A result-effective variable is a variable which achieves a recognized result. The determination of the optimum or workable ranges of a result-effective variable is routine experimentation and therefore obvious (MPEP § 2144.05.II). In the instant case, electrolyte viscosity is a variable that achieves the recognized result of affecting the lithium ion-transfer effect and wetting of the electrolyte, as taught by Kim, thus making electrolyte viscosity a result-effective variable. Therefore, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the electrolyte of modified Cao such that the electrolyte is characterized by a viscosity of less than or about 10 cP at 23 °C via routine experimentation, for the purpose of achieving an electrolyte with suitable lithium ion-transfer effect and wetting.
Regarding Claim 12, modified Cao discloses the electrolyte as set forth above. Cao further discloses ([0147]) wherein the one or more lithium salts comprise one or more of LiPF6, LiAsF6, LiBF4, LiClO4, LiCF3SO3, LiN(CF3SO2)2 (see LiTFSI), LiN(C2F5SO2)2 (see LiBETI), and LiN(SO2F)2 (see LiFSI).
Regarding Claims 14 and 25, modified Cao discloses the electrolyte as set forth above. Cao discloses wherein the solvent is free of carbonate-containing compounds (Claim 25), and wherein the electrolyte comprises 0 wt. % of carbonate-containing compounds (Claim 14), as Cao does not require carbonate compounds be included in the electrolyte (note that [0148] discloses carbonate solvents as one option amongst a list of other types of solvents for electrolytes which can be used; note also that [0166] discloses carbonate compounds as possible bridge solvents, but does not require them and also lists non-carbonate options such as acetonitrile).
Claims 9, 13, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Cao et al. (US 2020/0161706 A1) in view of Chen et al. (“Toward wide-temperature electrolyte for lithium-ion batteries”), further in view of Kim et al. (US 2022/0131192 A1), further in view of Park et al. (US 2023/0093801 A1), as evidenced by PubChem (“Compound summary of 2-Fluoro-4-methyl-1,3,2-dioxaphospholane”).
Regarding Claims 9 and 13, modified Cao discloses the electrolytes as set forth above. Modified Cao further discloses wherein the phosphorous-containing additive has the formula shown in Claims 9 and 13 of the Instant Application, as Park teaches ([0072]–[0073]) that the phosphorous-containing additive may be 2-fluoro-4-methyl-1,3,2-dioxaphospholane ([0072]–[0073]), evidenced by PubChem (p. 2, section 1.1 2D Structure) to match the formula shown in Claims 9 and 13.
Regarding Claim 20, modified Cao discloses the lithium-containing battery cell as set forth above, but does not explicitly disclose wherein the battery cell is characterized by a change in battery cell impedance of less than or about 40% after greater than or about 600 charging cycles.
Park discloses an electrolyte (see electrolyte solution, [0054]) for a lithium-containing battery cell (see rechargeable lithium battery 100, [0053]), the electrolyte comprising a solvent comprising at least one non-carbonate-containing ester compound (see non-aqueous organic solvent, [0055], [0079]–[0080]), one or more lithium salts [0055]); and a diluent comprising a fluorinated organic compound (see aromatic hydrocarbon-based organic solvent, examples of which include fluorinated organic compounds, [0089]). Park teaches wherein the electrolyte further comprises a phosphorous-containing additive (see compound represented by Chemical Formula 1, [0055]–[0059]) which may be 2-fluoro-4-methyl-1,3,2-dioxaphospholane ([0072]–[0073]), evidenced by PubChem (p. 2, section 1.1 2D Structure) to match the formula shown in e.g. [0067] of the Instant Specification. Park teaches ([0060]) that the phosphorous-containing additive has suitable or high high-temperature stability on the surface of the negative electrode, forms a solid electrolyte interface (SEI) with suitable or excellent ion conductivity, and suppresses a side reaction of LiPF6 to reduce the gas generation caused by a decomposition reaction of the electrolyte solution during high-temperature storage.
Park is analogous to the claimed invention as it is in the same field of secondary batteries capable of cycling lithium. It therefore would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the lithium-containing battery cell of modified Cao such that the electrolyte further comprises the phosphorous-additive described above, i.e. 2-fluoro-2-methyl-1,3,2-dioxaphospholane, as it has suitable or high high-temperature stability on the surface of the negative electrode, forms an SEI with suitable or excellent ion conductivity, and suppresses a side reaction of LiPF6 to reduce the gas generation caused by a decomposition reaction of the electrolyte solution during high-temperature storage.
In the Instant Specification, Applicant discloses ([0011]) that the electrical impedance of a battery cell can be lowered by including an electrolyte that is highly concentrated in lithium ions, and ([0029], [0048]) that including the phosphorous-containing additive shown in e.g. [0006] of the Instant Specification in the electrolyte can reduce the growth rate of the battery cell’s impedance over an extended number of charge/discharge cycles.
Accordingly, it is reasonably interpreted that a high concentration of lithium ions (already the case for modified Cao as set forth in the rejection of Claim 15 above) and the presence of the phosphorous-containing additive shown in e.g. [0006] of the Instant Specification in the electrolyte are critical to the instant lithium-containing battery cell such that it would fulfill the recited measurements and necessarily possess the inherent properties, i.e. be characterized by a change in battery cell impedance of less than or about 40% after greater than or about 600 charging cycles.
MPEP § 2112.01.II states that where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established.
It is submitted that the lithium-containing battery cell of modified Cao is substantially similar to the instant lithium-containing battery cell. Based upon such substantial similarities, it appears reasonable that the lithium-containing battery cell of modified Cao would inherently possess properties such that the lithium-containing battery cell would necessarily fulfill the recited limitations, i.e. be characterized by a change in battery cell impedance of less than or about 40% after greater than or about 600 charging cycles.
Claim 19 is rejected under 35 U.S.C. 103 as being unpatentable over Cao et al. (US 2020/0161706 A1) in view of Chen et al. (“Toward wide-temperature electrolyte for lithium-ion batteries”), and further in view of Kim et al. (US 2022/0131192 A1), as applied to Claims 1, 5, 7, 15, and 21 above, as evidenced by Gill et al. (“Viscosity of Esters of Saturated Aliphatic Acids—Relation to the Synthesis of Fine Lubricating Oils”).
Regarding Claim 19, modified Cao discloses the lithium-containing battery cell as set forth above. Modified Cao does not explicitly disclose wherein the battery cell is characterized by a swelling volume percentage of less than or about 10 vol. % after operating at 85 °C for 8 hours. It is submitted, however, that such limitations are simply measurements of, and thus descriptions of, inherent properties of the claimed lithium-containing battery cell.
In the Instant Specification, Applicant discloses ([0065]–[0067], FIG. 7) the results of battery swelling measurements wherein the volumes of batteries of varying compositions were measured before and after the batteries were operated at 85 °C for 8 hours. Applicant specifically discloses a battery cell with a lithium-cobalt-oxide positive electrode ([0064]), a graphite negative electrode ([0064]), and an electrolyte comprising a non-carbonate-containing solvent (e.g. propyl propionate; [0066]), a diluent ([0066]), and lithium salts ([0066], FIG. 7) wherein the solvent/salt molar ratio is approximately 1.18 ([0066], FIG. 7), that exhibits a swelling volume percentage of below 8% after operating at 85 °C for 8 hours (FIG. 7).
Accordingly, it is reasonably interpreted that the identities of the positive and negative electrodes, the solvent/salt molar ratio, the non-carbonate-containing solvent, and the diluent are critical to the instant lithium-containing battery cell such that it would fulfill the recited measurements and necessarily possess the inherent properties.
As described above with regards to Claim 15, modified Cao discloses a battery cell (100) with a positive electrode (120), a negative electrode (140), an electrolyte with lithium salts, a non-carbonate-containing solvent, and a diluent. Cao further discloses that the positive electrode (120) can be a lithium-cobalt-oxide positive electrode ([0175]) that the negative electrode (140) can be a graphite negative electrode ([0174]), and that the solvent/salt molar ratio can range from 0.5 to 1.5 ([0153]). While the limitations of Claim 15 exclude the selection of propyl propionate as the non-carbonate-containing solvent, butyl propionate, disclosed by modified Cao with regards to Claim 15 above, is, like propyl propionate, a linear ester compound, and has a comparable viscosity (0.7618 cP at 25 °C) to propyl propionate (0.0.6104 cP at 25 °C), as evidenced by Gill (Table 1).
MPEP § 2112.01.II states that where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established.
It is submitted that the lithium-containing battery cell of modified Cao is substantially similar to the instant lithium-containing battery cell. Based upon such substantial similarities, it appears reasonable that the lithium-containing battery cell of modified Cao would inherently possess properties such that the lithium-containing battery cell would necessarily fulfill the recited limitations, i.e. wherein the battery cell is characterized by a swelling volume percentage of less than or about 10 vol. % after operating at 85 °C for 8 hours.
Response to Arguments
Applicant’s arguments in the Remarks filed 2 February 2026 regarding the 35 U.S.C. § 103 rejections in the office action mailed 1 October 2025 have been fully considered but they are not persuasive for the following reasons:
Applicant argues on p. 9–10 of Remarks that it would not have been obvious to routinely experiment with the viscosity of the electrolyte to achieve the purported result of improved ion transfer and electrolyte wetting because of additional limitations of the independent claims. Applicant argues specifically that arbitrarily decreasing the viscosity of the compounds in the electrolyte will also decrease the concentration of the lithium salts, as the electrolyte characteristics of lithium ion concentration and viscosity are at cross-purposes in conventional electrolytes, and thus it would not be obvious to the skilled artisan to vary the viscosity of the electrolyte of modified Cao to less than about 10 cP (or 5 cP) without a teaching that the claimed viscosities are achievable in conjunction with the claimed high concentration of lithium salts in the solvent.
This argument is not persuasive. As set forth in the rejections above, primary reference Cao discloses a range of lithium salt concentration of 0.1 to 30 mol/L which significantly overlaps with the claimed range of 2.02 mol/L or more, and further renders obvious the claimed range. Furthermore, teaching reference Kim establishes viscosity as a result-effective variable that achieves a recognized result of affecting ion transfer and electrolyte wetting. Considering the disclosures of Cao and Kim, a person of ordinary skill in the art would have found it obvious to determine the optimum or workable ranges of the viscosity of the electrolyte via routine experimentation, as set forth in MPEP § 2144.05.II and described in the rejections above. Regarding Applicant’s specific argument that only a teaching that the claimed viscosities are achievable in conjunction with the claimed high concentration of lithium salts in the solvent would have rendered obvious varying the viscosity of the electrolyte of modified Cao to less than or about 10 cP (or 5 cP), it is submitted that this is not the case, as again considering the disclosures of Cao and Kim and MPEP § 2144.05.II, and also considering that Applicant has not demonstrated sufficient criticality of the above ranges, such a teaching would not have been necessary and a person of ordinary skill in the art would have found the above optimizations within the claimed ranges a matter of routine experimentation.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/J.M.F./Examiner, Art Unit 1725
/BASIA A RIDLEY/Supervisory Patent Examiner, Art Unit 1725
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