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 .
Priority
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 08/11/2023 was filed in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
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.
Claim(s) 1-10, 14, 16-17, and 19 is/are rejected under 35 U.S.C. 103 as being unpatentable over Zhang et al. (US 20160240896 A1) in view of Shen et al. (US 20210020986 A1), and as evidenced by “Chemical Book: 1,2-dimethoxyethane (DME)” (<https://www.chemicalbook.com/ChemicalProductProperty_EN_CB9232185.htm>, accessed 2026); “Chemical Book: Lithium bis(fluorosulfonyl)imide” (<https://www.chemicalbook.com/ChemicalProductProperty_EN_CB82604260.htm>, accessed 2026); Ramirez et al. (“A Comparison among Viscosity, Density, Conductivity, and Electrochemical Windows of N-n-Butyl-N-methylpyrrolidinium and Triethyl-n-pentylphosphonium Bis(fluorosulfonyl imide) Ionic Liquids and Their Analogues Containing Bis(trifluoromethylsulfonyl) Imide Anion”, J. Chem. Eng. Data 2017, 62, 3437−3444, DOI: 10.1021/acs.jced.7b00458) and Proionic (“PYRR14 FSI (CAS 1057745-51-3) > 99.9%, "1-Butyl-1-methylpyrrolidiniumbis(fluorosulfonyl)imide", <https://www.proionic.com/product/1-butyl-1-methylpyrrolidinium-bisfluorosulfonylimide/>, accessed 2026).
Regarding claim 1, Zhang teaches an electrolyte (electrolyte [0039, 0061-0066]; e.g. 3 M to 6 M lithium bis(fluorosulfonyl)imide (LiFSI) in 1,2-dimethoxyethane (DME) per [0008, 0064]) for an anode-free electrochemical cell (an anode-free battery, [0022]; a highly stable electrolyte and a stable anode current collector allow for the practical application of the anode-free rechargeable battery per [0062]) that cycles lithium ions (cycling the rechargeable alkali metal battery where M may be Li, [0006]; the electrolyte has a Li+ concentration, [0008]; Li plated and stripped during cycling, [0015]; Li+ intercalation, [0041-0042]), the electrolyte comprising:
greater than or equal to about 20 wt.% to less than or equal to about 99.5 wt.% (“consists essentially of” option in [0063] – see also below calculations) of a concentrated electrolyte (a lithium salt dissolved in a solvent as majority component, [0063]), having a lithium salt concentration (concentration of lithium salt in the electrolyte, [0064]; lithium salt such as lithium bis(fluorosulfonyl)imide (LiFSI), [0008, 0063-0064]) greater than or equal to about 2 M to less than or equal to about 6 M (e.g. 3 M to 6 M LiFSI in DME, [0008, 0064]; EXAMPLE: 4 M LiFSI-DME as the liquid electrolyte in [0083]); and
greater than or equal to about 0.5 wt.% to less than or equal to about 80 wt.% (see also below calculations) of an ionic [compound] (“consists essentially of” also means that the electrolyte may include other non-electrochemically active components … Typical additives that do not affect the battery performance may include nonmetal halide salts, such as ammonium chloride (NH4Cl) or tetraethylammonium chloride (Et4NCl); [0063]), wherein
the anode-free electrochemical cell (EXAMPLE: Cu|LiFePO4 Anode-free Li rechargeable cells, [0083]) comprises a positive electrode (positive electrode / cathode, [0057]; EXAMPLE: LiFePO4 coated on Al foil in [0083]) and a negative electrode current collector (an anode current collector and no anode, [0006]; Anode-free refers to an initial cell configuration in which an alkali metal or carbon-based anode is not present prior to an initial charge cycle of the battery, [0028]; EXAMPLE: copper (Cu) foil in [0083]) configured to receive a negative electroactive material and form a negative electrode after one or more formation cycles of the anode-free electrochemical cell (During a first charge cycle an alkali metal anode is formed in situ on the anode current collector as alkali metal cations are reduced and deposit on the anode current collector, [0028]; in anode-free configuration the electrolyte and/or cathode serves as the source of the anode material that is formed during the charging process, [0051]).
However, as cited above, although Zhang [0063] teaches the concentrated electrolyte of lithium salt dissolved in solvent as majority component (“consists essentially of”, cited above – thus presumably falling within a range of greater than 50% to obviate 20-99.5 wt.%) and ionic compounds (such as ammonium chloride or tetraethylammonium chloride, cited above – where NH4+ or [N(CH2CH3)4]+ would be the cation and Cl- would be anion) as minor additives, these compounds are known in the art to be solids, such that Zhang fails to teach such additive being an ionic liquid. Zhang also fails to teach the specific ranges of “20 wt.% to less than or equal to about 99.5 wt.%” of the concentrated electrolyte nor “0.5 wt.% to less than or equal to about 80 wt.%” of the ionic liquid.
Shen is analogous in the art of electrolyte for anode-free rechargeable battery (title) and teaches the electrolyte includes an ionic liquid and an electrolyte salt dispersed in the ionic liquid (abstract). Shen teaches in [0018] the incorporation of ionic liquid having low melting point, high ionic conductivity, solubility with many compounds, negligible volatility, flame retardancy, moderate viscosity, high polarity, etc. into the electrolytes can be used to improve the safety of the electrolytes because the introduction of the ionic liquid can prevent fire and explosion caused by the excessive rise of temperature in the battery, so as to improve the safety of the battery. Shen teaches in [0019] that the cations of the ionic liquid may be, for example, organic nitrogen cation (including exemplary ammonium cations, e.g. quaternary ammonium cation, as listed in Shen [0019]). Such “quaternary ammonium cation” is similar to the “tetraethylammonium” cation – i.e., [Et4N]+ – in the exemplary tetraethylammonium chloride additive of Zhang [0063] as cited above. Shen further teaches non-limiting examples of suitable anions of the ionic liquid include Cl−, bis(fluorosulfonyl)imide, and etc. (Shen [0020]). Such Cl− anion is similar to that of Zhang [0063] additive as cited above, and bis(fluorosulfonyl)imide correlates to the lithium “bis(fluorosulfonyl)imide” salt component cited above to Zhang, e.g. at Zhang [0008]. Shen teaches battery performance is generally affected by the cation, and that the cations have more significant influence on the viscosity of the electrolytes per [0019], and teaches that the anion of the ionic liquid plays a substantial role in the electrochemical stability and consequently wideness of the potential window per [0020]. Thus, Shen teaches that since ionic liquids are basically composed of ions (cations and anions as cited above) that may undergo almost unlimited structural variations because of the easy preparation of a large variety of their components ([0019]) such that various kinds of ionic liquids can be used in the ionic liquid electrolyte ([0021]). Shen [0021] teaches the ionic liquid has a melting point less than 100°C, giving a suitable example of N-Butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide (Py14FSI) (see Shen [0021]). In the electrolyte, Shen further teaches inclusion of electrolyte salt wherein the ionic liquid and the electrolyte salt have the same anion ([0030]), listing exemplary lithium bis(fluorosulfonyl)imide (LiFSI) in [0030] (which is the same LiFSI electrolyte salt of Zhang [0008, 0083] as cited above), having the same bis(fluorosulfonyl)imide anion as listed in [0020] for the exemplary ionic liquid. Shen specifically teaches in [0031] toward enhanced solvation in high concentration electrolytes, e.g. > 3 M, can effectively stabilize the solvent molecules and mitigate anode and electrolyte degradation during extended cycling, giving the example of concentrated lithium bis(fluorosulfonyl) imide (LiFSI) in the electrolyte which showed remarkable stability against reduction by Li and enabled dendrite-free and extremely stable cycling. This teaching agrees with the 3 M to 6 M LiFSI concentration, and specifically 4 M, in DME taught in Zhang [0064, 0083] as cited above. Shen also teaches in [0028] that organic carbonates have excellent stability at negative potentials, and the presence of organic carbonates is able to extend the electrochemical stability of ionic liquids, listing 1,2-dimethoxyethane carbonates (DME) as an example of organic carbonate additive for use in the ionic liquid electrolyte. Shen [0029] teaches the additives can be present from at least 1 wt.% and no more than 20 wt.% as a weight percentage based on the total weight of the electrolyte. Shen [0062] specifically gives inventive examples mixing an ionic liquid with DME (4:1 by weight) and 4M LiFSI. Therefore, the amount of DME is 20 wt.% compared to 80 wt.% of ionic liquid. In Shen [0062], the ionic liquid of inventive Example 6 is Py14FSI used alongside the DME and LiFSI. 4M is the same concentration as 4M LiFSI within the inventive example of Zhang [0083] cited above. The following chemical properties are used to calculate weight percentages based on the above prior art data:
As evidenced by “Chemical Book: 1,2-dimethoxyethane (DME)” the density of 1,2-dimethoxyethane (DME) is 0.867 g/mL and its molecular weight is 90.12 [units of 1 a.m.u. = 1 g/mol as known in the chemical arts] (see attached DME NPL at pg. 2). “Chemical Book: 1,2-dimethoxyethane (DME)” NPL further notes (see pg. 13 of attachment) that 1,2-dimethoxyethane is also known as glyme or monoglyme, and is widely used as a solvent for electrolyte of lithium batteries.
As evidenced by “Chemical Book: Lithium bis(fluorosulfonyl)imide”, the molecular weight of Lithium bis(fluorosulfonyl)imide (LiFSI) is 187.072 [units of 1 a.m.u. = 1 g/mol as known in the chemical arts] and its density is 1.052 g/cm3 (see attached LiFSI NPL at pg. 2). “Chemical Book: Lithium bis(fluorosulfonyl)imide” NPL further notes (see pg. 6 of attachment) that Lithium bis(fluorosulfonyl)imide is useful as electrolyte additive for lithium ion batteries.
As evidenced by Ramirez, the density of N-n-butyl-N-methylpyrrolidinium bis(fluorosulfonyl imide) [BMPYR][FSI] at Standard Ambient Temperature and Pressure (298.15K, 0.1MPa) is 1.307 g/cm3 (Ramirez Table 2 on pg. 3439).
As evidenced by Proionic, “1-Butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide” is synonymous with “N-Butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide”, “Bmpyr FSI”, and “PYR14 FSI” (see attached Proionic NPL at pg. 2), and the molecular weight of such is 322.39 g/mol (see attached Proionic NPL at pg. 2).
Therefore, since Shen (in inventive Example 6 as cited above) teaches Py14FSI ionic liquid with DME (4:1 by weight) and 4M LiFSI, and Zhang (in the inventive example of [0083] cited above) also teaches 4 M LiFSI-DME as the liquid electrolyte, the following weight percentage calculations are performed using the above-evidences chemical properties of densities and molecular weights:
o
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b
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o
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100
g
l
i
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u
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d
,
a
t
4
:
1
w
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i
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t
r
a
t
i
o
P
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14
F
S
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t
o
D
M
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:
100
g
=
80
g
P
y
14
F
S
I
+
20
g
D
M
E
a
n
d
:
0.023068
L
D
M
E
0.084277
L
t
o
t
a
l
l
i
q
u
i
d
=
27.37
v
o
l
%
D
M
E
,
o
f
l
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d
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s
Examiner notes that 68.25 wt.% concentrated electrolyte falls within the instantly claimed range “greater than or equal to about 20 wt.% to less than or equal to about 99.5 wt.%”, and 31.75 wt.% ionic liquid falls within the instantly claimed range “greater than or equal to about 0.5 wt.% to less than or equal to about 80 wt.%”. In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exist (MPEP 214.05 I).
It would have been obvious, at the time of filing, for a person having ordinary skill in the art to modify the electrolyte of the anode-free battery of Zhang to also include an ionic liquid like that within the electrolyte of Shen, and in the above-explained amounts, with the motivation of achieving improved the safety of the electrolytes due to fire prevention properties of ionic liquid, as taught toward by Shen. Also, the selection of a known material based on its suitability for its intended use supports a prima facie obviousness determination (MPEP 2144.07) and simple substitution of one known element for another to obtain predictable results supports a conclusion of obviousness (MPEP 2143 I B), such that using the Py14FSI + DME + LiFSI electrolyte of Shen in place of the DME + LiFSI electrolyte of Zhang would have been obvious.
Thus, the instant claim 1 is rendered obvious.
Regarding claim 2 and claim 3, modified Zhang teaches the limitations of claim 1 above and teaches the concentrated electrolyte comprises a lithium salt (Zhang [0063-0064]), wherein the lithium salt comprises lithium bis(fluorosulfonyl)imide (LiFSI) (4M LiFSI, Zhang [0008, 0064, 0083]; see also Shen [0063] Example 6 having LiFSI as lithium salt within the ionic liquid electrolyte, as applied to modified Zhang above).
Regarding claim 4 and claim 5, modified Zhang teaches the limitations of claim 1 above and teaches the concentrated electrolyte comprises a solvent (lithium salt dissolved in a solvent, Zhang [0063]), wherein the solvent comprises dimethoxyethane (DME) (in DME solvent, Zhang [0008, 0064, 0083]; see also Shen [0063] Example 6 having DME within the ionic liquid electrolyte, as applied to modified Zhang above).
Regarding claim 6 and claim 7, modified Zhang teaches the limitations of claim 1 above and teaches the ionic liquid comprise a cation (cations per Shen [0019], applied to modified Zhang above), wherein the cation comprises 1-butyl-1-methylpyrrolidinium ([Py14]+) (N-methyl-N-butyl-pyrrolidinium (P14) within N-Butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide (Py14FSI), Shen [0019-0020]; ionic liquid in Example 6 is Py14FSI, Shen [0062] – as applied within modified Zhang electrolyte above; see also Proionic NPL pg. 2 as cited above, evidencing that: “1-Butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide” is synonymous with “N-Butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide”, “Bmpyr FSI”, and “PYR14 FSI”).
Regarding claim 8, modified Zhang teaches the limitations of claim 1 above and teaches the ionic liquid comprises an anion selected from … bis(fluorosulfonyl)imide (FSI) (bis(fluorosulfonyl)imide anion of Shen [0020] within the resultant ionic liquid of Py14FSI per Shen [0021, 0062] as applied to modified Zhang electrolyte).
Regarding claim 9, modified Zhang teaches the limitations of claim 6 above but fails to yet explicitly teach the anion comprises bis(trifluoromethanesulfonyl)imide (TFSI) or difluoro(oxalato)borate (DFOB).
However, Shen – which is the basis for teaching toward the ionic liquid included within the modified multi-component electrolyte of Zhang above, to improve battery safety by imparting fire preventative properties (see Shen [0002, 0018, 0102]) – teaches, in addition to the bis(fluorosulfonyl)imide anion used above, various options for the anion of the ionic liquid electrolyte, including difluoro(oxalato)borate (DFOB−) and bis(trifluoromethanesulfonyl)imide (TFSI−) (e.g., useful in Py14TFSI ionic liquid of Shen [0021]) as non-limiting examples of suitable anions (Shen [0020]). Shen further teaches in [0030] that the ionic liquid and the electrolyte salt can have the same anion and also lists in [0030] LiTFSI and LiDFOB useable as Li-salts (such that TFSI- and DFOB- are the corresponding anions). Also, Zhang [0036, 0045, 0063] gives both TFSI−: bis(trifluoromethanesulfonyl)imide and DFOB: difluoro(oxalate)borate as options for the anions of lithium salts useable in the electrolyte.
Therefore, when modifying Zhang in view of Shen to include the ionic liquid within the electrolyte, selecting from among the suitable anions listed in Shen (including non-limiting examples of TFSI and DFOB in addition to LFSI), a person having ordinary skill in the art would have found it obvious to select TFSI or DFOB instead of LFSI and still expect desirable fire-preventing properties to be imparted by the ionic liquid within the modified electrolyte. The selection of a known material based on its suitability for its intended use supports a prima facie obviousness determination (MPEP 2144.07), and simple substitution of one known element for another to obtain predictable results supports a conclusion of obviousness (MPEP 2143 I B).
Thereby, claim 9 is rendered obvious.
Regarding claim 10, modified Zhang teaches the limitations of claim 1 above and teaches the ionic liquid comprises a cation selected from … 1-butyl-1-methylpyrrolidinium ([Py14]+) (N-methyl-N-butyl-pyrrolidinium (P14) within N-Butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide (Py14FSI), Shen [0019-0020]; ionic liquid in Example 6 is Py14FSI, Shen [0062] – as applied within modified Zhang electrolyte above; see also Proionic NPL pg. 2 as cited above, evidencing that: “1-Butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide” is synonymous with “N-Butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide”, “Bmpyr FSI”, and “PYR14 FSI” – see also other suitable cation options of Shen [0019] overlapping the list of instant claim 10, and MPEP 2144.07); and an anion selected from … bis(fluorosulfonyl)imide (FSI) (bis(fluorosulfonyl)imide anion of Shen [0020] within the resultant ionic liquid of Py14FSI per Shen [0021, 0062] as applied to modified Zhang electrolyte – see also other suitable anion options of Shen [0020] overlapping the list of instant claim 10, and MPEP 2144.07).
Regarding claim 14, Zhang teaches An anode-free electrochemical cell (an anode-free battery, [0022]; a highly stable electrolyte and a stable anode current collector allow for the practical application of the anode-free rechargeable battery per [0062]) that cycles lithium ions (cycling the rechargeable alkali metal battery where M may be Li, [0006]; the electrolyte has a Li+ concentration, [0008]; Li plated and stripped during cycling, [0015]; Li+ intercalation, [0041-0042]), the anode-free electrochemical cell (EXAMPLE: Cu|LiFePO4 Anode-free Li rechargeable cells, [0083]) comprising:
a positive electrode assembly comprising a positive current collector and a positive electroactive material layer (positive electrode / cathode on a conductive substrate- e.g., a cathode current collector, [0057]; EXAMPLE: LiFePO4 coated on Al foil in [0083]);
a negative current collector comprising a surface (an anode current collector and no anode, [0006]; Anode-free refers to an initial cell configuration in which an alkali metal or carbon-based anode is not present prior to an initial charge cycle of the battery, [0028]; the surface of the bare anode current collector, [0051]; EXAMPLE: copper (Cu) foil in [0083]) configured to receive a negative electroactive material after one or more formation cycles of the anode-free electrochemical cell, wherein the negative current collector together with the negative electroactive material forms a negative electrode after the one or more formation cycles (During a first charge cycle an alkali metal anode is formed in situ on the anode current collector as alkali metal cations are reduced and deposit on the anode current collector, [0028, 0051]); and
a separating layer (porous sheet or film, [0044]) disposed between the positive electroactive material layer and the surface of the negative current collector (separator placed between the anode and cathode, [0044]), the separating layer comprising an electrolyte (separator infused with electrolyte, [0050]; electrolyte of [0039, 0061-0066] - e.g. 3 M to 6 M lithium bis(fluorosulfonyl)imide (LiFSI) in 1,2-dimethoxyethane (DME) per [0008, 0064]) that comprises:
greater than or equal to about 20 wt.% to less than or equal to about 99.5 wt.% (“consists essentially of” option in [0063] – see also below calculations) of a concentrated electrolyte (a lithium salt dissolved in a solvent as majority component, [0063]), having a lithium salt concentration (concentration of lithium salt in the electrolyte, [0064]; lithium salt such as lithium bis(fluorosulfonyl)imide (LiFSI), [0008, 0063-0064]) greater than or equal to about 2 M to less than or equal to about 6 M (e.g. 3 M to 6 M LiFSI in DME, [0008, 0064]; EXAMPLE: 4 M LiFSI-DME as the liquid electrolyte in [0083]); and
greater than or equal to about 0.5 wt.% to less than or equal to about 80 wt.% (see also below calculations) of an ionic [compound] (“consists essentially of” also means that the electrolyte may include other non-electrochemically active components … Typical additives that do not affect the battery performance may include nonmetal halide salts, such as ammonium chloride (NH4Cl) or tetraethylammonium chloride (Et4NCl); [0063]).
However, as cited above, although Zhang [0063] teaches the concentrated electrolyte of lithium salt dissolved in solvent as majority component (“consists essentially of”, cited above – thus presumably falling within a range of greater than 50% to obviate 20-99.5 wt.%) and ionic compounds (such as ammonium chloride or tetraethylammonium chloride, cited above – where NH4+ or [N(CH2CH3)4]+ would be the cation and Cl- would be anion) as minor additives, these compounds are known in the art to be solids, such that Zhang fails to teach such additive being an ionic liquid. Zhang also fails to teach the specific ranges of “20 wt.% to less than or equal to about 99.5 wt.%” of the concentrated electrolyte nor “0.5 wt.% to less than or equal to about 80 wt.%” of the ionic liquid.
Shen is analogous in the art of electrolyte for anode-free rechargeable battery (title) and teaches the electrolyte includes an ionic liquid and an electrolyte salt dispersed in the ionic liquid (abstract). Shen teaches in [0018] the incorporation of ionic liquid having low melting point, high ionic conductivity, solubility with many compounds, negligible volatility, flame retardancy, moderate viscosity, high polarity, etc. into the electrolytes can be used to improve the safety of the electrolytes because the introduction of the ionic liquid can prevent fire and explosion caused by the excessive rise of temperature in the battery, so as to improve the safety of the battery. Shen teaches in [0019] that the cations of the ionic liquid may be, for example, organic nitrogen cation (including exemplary ammonium cations, e.g. quaternary ammonium cation, as listed in Shen [0019]). Such “quaternary ammonium cation” is similar to the “tetraethylammonium” cation – i.e., [Et4N]+ – in the exemplary tetraethylammonium chloride additive of Zhang [0063] as cited above. Shen further teaches non-limiting examples of suitable anions of the ionic liquid include Cl−, bis(fluorosulfonyl)imide, and etc. (Shen [0020]). Such Cl− anion is similar to that of Zhang [0063] additive as cited above, and bis(fluorosulfonyl)imide correlates to the lithium “bis(fluorosulfonyl)imide” salt component cited above to Zhang, e.g. at Zhang [0008]. Shen teaches battery performance is generally affected by the cation, and that the cations have more significant influence on the viscosity of the electrolytes per [0019], and teaches that the anion of the ionic liquid plays a substantial role in the electrochemical stability and consequently wideness of the potential window per [0020]. Thus, Shen teaches that since ionic liquids are basically composed of ions (cations and anions as cited above) that may undergo almost unlimited structural variations because of the easy preparation of a large variety of their components ([0019]) such that various kinds of ionic liquids can be used in the ionic liquid electrolyte ([0021]). Shen [0021] teaches the ionic liquid has a melting point less than 100°C, giving a suitable example of N-Butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide (Py14FSI) (see Shen [0021]). In the electrolyte, Shen further teaches inclusion of electrolyte salt wherein the ionic liquid and the electrolyte salt have the same anion ([0030]), listing exemplary lithium bis(fluorosulfonyl)imide (LiFSI) in [0030] (which is the same LiFSI electrolyte salt of Zhang [0008, 0083] as cited above), having the same bis(fluorosulfonyl)imide anion as listed in [0020] for the exemplary ionic liquid. Shen specifically teaches in [0031] toward enhanced solvation in high concentration electrolytes, e.g. > 3 M, can effectively stabilize the solvent molecules and mitigate anode and electrolyte degradation during extended cycling, giving the example of concentrated lithium bis(fluorosulfonyl) imide (LiFSI) in the electrolyte which showed remarkable stability against reduction by Li and enabled dendrite-free and extremely stable cycling. This teaching agrees with the 3 M to 6 M LiFSI concentration, and specifically 4 M, in DME taught in Zhang [0064, 0083] as cited above. Shen also teaches in [0028] that organic carbonates have excellent stability at negative potentials, and the presence of organic carbonates is able to extend the electrochemical stability of ionic liquids, listing 1,2-dimethoxyethane carbonates (DME) as an example of organic carbonate additive for use in the ionic liquid electrolyte. Shen [0029] teaches the additives can be present from at least 1 wt.% and no more than 20 wt.% as a weight percentage based on the total weight of the electrolyte. Shen [0062] specifically gives inventive examples mixing an ionic liquid with DME (4:1 by weight) and 4M LiFSI. Therefore, the amount of DME is 20 wt.% compared to 80 wt.% of ionic liquid. In Shen [0062], the ionic liquid of inventive Example 6 is Py14FSI used alongside the DME and LiFSI. 4M is the same concentration as 4M LiFSI within the inventive example of Zhang [0083] cited above. The following chemical properties are used to calculate weight percentages based on the above prior art data:
As evidenced by “Chemical Book: 1,2-dimethoxyethane (DME)” the density of 1,2-dimethoxyethane (DME) is 0.867 g/mL and its molecular weight is 90.12 [units of 1 a.m.u. = 1 g/mol as known in the chemical arts] (see attached DME NPL at pg. 2). “Chemical Book: 1,2-dimethoxyethane (DME)” NPL further notes (see pg. 13 of attachment) that 1,2-dimethoxyethane is also known as glyme or monoglyme, and is widely used as a solvent for electrolyte of lithium batteries.
As evidenced by “Chemical Book: Lithium bis(fluorosulfonyl)imide”, the molecular weight of Lithium bis(fluorosulfonyl)imide (LiFSI) is 187.072 [units of 1 a.m.u. = 1 g/mol as known in the chemical arts] and its density is 1.052 g/cm3 (see attached LiFSI NPL at pg. 2). “Chemical Book: Lithium bis(fluorosulfonyl)imide” NPL further notes (see pg. 6 of attachment) that Lithium bis(fluorosulfonyl)imide is useful as electrolyte additive for lithium ion batteries.
As evidenced by Ramirez, the density of N-n-butyl-N-methylpyrrolidinium bis(fluorosulfonyl imide) [BMPYR][FSI] at Standard Ambient Temperature and Pressure (298.15K, 0.1MPa) is 1.307 g/cm3 (Ramirez Table 2 on pg. 3439).
As evidenced by Proionic, “1-Butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide” is synonymous with “N-Butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide”, “Bmpyr FSI”, and “PYR14 FSI” (see attached Proionic NPL at pg. 2), and the molecular weight of such is 322.39 g/mol (see attached Proionic NPL at pg. 2).
Therefore, since Shen (in inventive Example 6 as cited above) teaches Py14FSI ionic liquid with DME (4:1 by weight) and 4M LiFSI, and Zhang (in the inventive example of [0083] cited above) also teaches 4 M LiFSI-DME as the liquid electrolyte, the following weight percentage calculations are performed using the above-evidences chemical properties of densities and molecular weights:
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100
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,
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4
:
1
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14
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:
100
g
=
80
g
P
y
14
F
S
I
+
20
g
D
M
E
a
n
d
:
0.023068
L
D
M
E
0.084277
L
t
o
t
a
l
l
i
q
u
i
d
=
27.37
v
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%
D
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,
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s
Examiner notes that 68.25 wt.% concentrated electrolyte falls within the instantly claimed range “greater than or equal to about 20 wt.% to less than or equal to about 99.5 wt.%”, and 31.75 wt.% ionic liquid falls within the instantly claimed range “greater than or equal to about 0.5 wt.% to less than or equal to about 80 wt.%”. In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exist (MPEP 214.05 I).
It would have been obvious, at the time of filing, for a person having ordinary skill in the art to modify the electrolyte of the anode-free battery of Zhang to also include an ionic liquid like that within the electrolyte of Shen, and in the above-explained amounts, with the motivation of achieving improved the safety of the electrolytes due to fire prevention properties of ionic liquid, as taught toward by Shen. Also, the selection of a known material based on its suitability for its intended use supports a prima facie obviousness determination (MPEP 2144.07) and simple substitution of one known element for another to obtain predictable results supports a conclusion of obviousness (MPEP 2143 I B), such that using the Py14FSI + DME + LiFSI electrolyte of Shen in place of the DME + LiFSI electrolyte of Zhang would have been obvious.
Thus, the instant claim 14 is rendered obvious.
Regarding claim 16, modified Zhang teaches the limitations of claim 14 above and teaches the concentrated electrolyte comprises a lithium salt (a lithium salt dissolved in a solvent, Zhang [0063]) selected from … lithium bis(fluorosulfonyl)imide (LiFSI) (4M LiFSI, Zhang [0008, 0064, 0083]; see also Shen [0063] Example 6 having LiFSI as lithium salt within the ionic liquid electrolyte, as applied to modified Zhang above), and
a solvent (a lithium salt dissolved in a solvent, Zhang [0063]) selected from … dimethoxyethane (DME) (in DME solvent, Zhang [0008, 0064, 0083]; see also Shen [0063] Example 6 having DME within the ionic liquid electrolyte, as applied to modified Zhang above).
Regarding claim 17, modified Zhang teaches the limitations of claim 14 above and teaches the ionic liquid comprises a cation selected from … 1-butyl-1-methylpyrrolidinium ([Py14]+) (N-methyl-N-butyl-pyrrolidinium (P14) within N-Butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide (Py14FSI), Shen [0019-0020]; ionic liquid in Example 6 is Py14FSI, Shen [0062] – as applied within modified Zhang electrolyte above; see also Proionic NPL pg. 2 as cited above, evidencing that: “1-Butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide” is synonymous with “N-Butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide”, “Bmpyr FSI”, and “PYR14 FSI” – see also other suitable cation options of Shen [0019] overlapping the list of instant claim 10, and MPEP 2144.07);
and an anion selected from … bis(fluorosulfonyl)imide (FSI) (bis(fluorosulfonyl)imide anion of Shen [0020] within the resultant ionic liquid of Py14FSI per Shen [0021, 0062] as applied to modified Zhang electrolyte – see also other suitable anion options of Shen [0020] overlapping the list of instant claim 17, and MPEP 2144.07).
Regarding claim 19, Zhang teaches an electrolyte (electrolyte [0039, 0061-0066]; e.g. 3 M to 6 M lithium bis(fluorosulfonyl)imide (LiFSI) in 1,2-dimethoxyethane (DME) per [0008, 0064]) for an anode-free electrochemical cell (an anode-free battery, [0022]; a highly stable electrolyte and a stable anode current collector allow for the practical application of the anode-free rechargeable battery per [0062]) that cycles lithium ions (cycling the rechargeable alkali metal battery where M may be Li, [0006]; the electrolyte has a Li+ concentration, [0008]; Li plated and stripped during cycling, [0015]; Li+ intercalation, [0041-0042]), the electrolyte comprising:
greater than or equal to about 20 wt.% to less than or equal to about 99.5 wt.% (“consists essentially of” option in [0063] – see also below calculations) of a concentrated electrolyte (a lithium salt dissolved in a solvent as majority component, [0063]), having a lithium salt concentration (concentration of lithium salt in the electrolyte, [0064]; lithium salt such as lithium bis(fluorosulfonyl)imide (LiFSI), [0008, 0063-0064]) greater than or equal to about 2 M to less than or equal to about 6 M (e.g. 3 M to 6 M LiFSI in DME, [0008, 0064]; EXAMPLE: 4 M LiFSI-DME as the liquid electrolyte in [0083]), wherein the concentrated electrolyte comprises:
a lithium salt (a lithium salt dissolved in a solvent, Zhang [0063]) selected from … lithium bis(fluorosulfonyl)imide (LiFSI) (e.g. 4M LiFSI, Zhang [0008, 0064, 0083]; see also Shen [0063] Example 6 having LiFSI as lithium salt within the ionic liquid electrolyte, as applied to modified Zhang below in the present rejection), and
a solvent (a lithium salt dissolved in a solvent. Zhang [0063]) selected from … dimethoxyethane (DME) (e.g. in DME solvent, Zhang [0008, 0064, 0083]; see also Shen [0063] Example 6 having DME within the ionic liquid electrolyte, as applied to modified Zhang below in the present rejection); and
greater than or equal to about 0.5 wt.% to less than or equal to about 80 wt.% (see also below calculations) of an ionic [compound] (“consists essentially of” also means that the electrolyte may include other non-electrochemically active components … Typical additives that do not affect the battery performance may include nonmetal halide salts, such as ammonium chloride (NH4Cl) or tetraethylammonium chloride (Et4NCl); [0063]) comprising a cation (NH4+ or Et4+ per cited additive examples) and an anion (Cl- in cited additive examples).
However, as cited above, although Zhang [0063] teaches the concentrated electrolyte of lithium salt dissolved in solvent as majority component (“consists essentially of”, cited above – thus presumably falling within a range of greater than 50% to obviate 20-99.5 wt.%) and ionic compounds (such as ammonium chloride or tetraethylammonium chloride, cited above – where NH4+ or [N(CH2CH3)4]+ would be the cation and Cl- would be anion) as minor additives, these compounds are known in the art to be solids, such that Zhang fails to teach such additive being an ionic liquid. Zhang also fails to teach the specific ranges of “20 wt.% to less than or equal to about 99.5 wt.%” of the concentrated electrolyte nor “0.5 wt.% to less than or equal to about 80 wt.%” of the ionic liquid. Zhang further fails to teach any such ionic liquid comprising:
[the] cation selected from the group consisting of: Li(triglyme) ([Li(G3)]+), Li(tetraglyme) ([Li(G4)]+), 1-ethyl-3-methylimidazolium ([Emim]+), 1-propyl-3-methylimidazolium ([Pmim]+), 1-butyl-3-methylimidazolium ([Bmim]+), 1,2-dimethyl-3-butylimidazolium ([DMBim]), 1-alkyl-3-methylimidazolium ([Cnmim]+), 1-allyl-3-methylimidazolium ([Amim]+), 1,3-diallylimidazolium ([Daim]+), 1-allyl-3-vinylimidazolium ([Avim]+), 1-vinyl-3-ethylimidazolium ([Veim]+), 1-cyanomethyl-3-methylimidazolium ([MCNim]+), 1,3-dicyanomethyl-imidazolium ([BCNim]+), 1-propyl-1-methylpiperidinium ([PP13]+), 1-butyl-1-methylpiperidinium ([PP14]+), 1-methyl-1-ethylpyrrolidinium ([Pyr12]+), 1-propyl-1-methylpyrrolidinium ([Pyr13]+), 1-butyl-1-methylpyrrolidinium ([Pyr14]+), methyl-methylcarboxymethyl-pyrrolidinium ([MMMPyr]+), tetramethylammonium ([N1111]+), tetraethylammonium ([N2222]+), tributylmethylammonium ([N4441]+), diallyldimethylammonium ([DADMA]+), N—N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium ([DEME]+), N,N-diethyl-N-(2-methacryloylethyl)-N-methylammonium ([DEMM]+), trimethylisobutyl-phosphonium ([P11114]+), triisobutylmethylphosphonium ([P11444]+), tributylmethylphosphonium ([P1444]+), diethylmethylisobutyl-phosphonium ([P1224]+), trihexdecylphosphonium ([P66610]+), trihexyltetradecylphosphonium ([P66614]+), and combinations thereof; nor
[the] anion selected from the group consisting of: hexafluoroarsenate, hexafluorophosphate, bis(fluorosulfonyl)imide (FSI), bis(trifluoromethanesulfonyl)imide (TFSI), perchlorate, tetrafluoroborate, cyclo-difluoromethane-1,1-bis(sulfonyl)imide (DMSI), bis(perfluoroethanesulfonyl)imide (BETI), bis(oxalate)borate (BOB), difluoro(oxalato)borate (DFOB), bis(fluoromalonato)boarate (BFMB), and combinations thereof.
Shen is analogous in the art of electrolyte for anode-free rechargeable battery (title) and teaches the electrolyte includes an ionic liquid and an electrolyte salt dispersed in the ionic liquid (abstract). Shen teaches in [0018] the incorporation of ionic liquid having low melting point, high ionic conductivity, solubility with many compounds, negligible volatility, flame retardancy, moderate viscosity, high polarity, etc. into the electrolytes can be used to improve the safety of the electrolytes because the introduction of the ionic liquid can prevent fire and explosion caused by the excessive rise of temperature in the battery, so as to improve the safety of the battery. Shen teaches in [0019] that the cations of the ionic liquid may be, for example, organic nitrogen cation (including exemplary ammonium cations, e.g. quaternary ammonium cation, as listed in Shen [0019]). Such “quaternary ammonium cation” is similar to the “tetraethylammonium” cation – i.e., [Et4N]+ – in the exemplary tetraethylammonium chloride additive of Zhang [0063] as cited above. Shen further teaches non-limiting examples of suitable anions of the ionic liquid include Cl−, bis(fluorosulfonyl)imide, and etc. (Shen [0020], see also Shen [0062] as applied below). Such Cl− anion is similar to that of Zhang [0063] additive as cited above, and bis(fluorosulfonyl)imide correlates to the lithium “bis(fluorosulfonyl)imide” salt component cited above to Zhang, e.g. at Zhang [0008] (Shen teaches in [0030] that the ionic liquid and the electrolyte salt have the same anion). Specifically, Shen teaches such ionic liquid (e.g. in inventive Example 6 of Shen [0062]) comprising:
a cation selected from … 1-butyl-1-methylpyrrolidinium ([Py14]+) (N-methyl-N-butyl-pyrrolidinium (P14) within N-Butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide (Py14FSI), Shen [0019-0020]; ionic liquid in Example 6 is Py14FSI, Shen [0062]; see also Proionic NPL pg. 2 evidencing that: “1-Butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide” is synonymous with “N-Butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide”, “Bmpyr FSI”, and “PYR14 FSI” – see also other suitable cation options of Shen [0019] overlapping the list of instant claim 19); and
an anion selected from … bis(fluorosulfonyl)imide (FSI) (bis(fluorosulfonyl)imide anion of Shen [0020] within the resultant ionic liquid of Py14FSI per Shen [0021, 0062]– see also other suitable anion options of Shen [0020] overlapping the list of instant claim 19).
Shen teaches battery performance is generally affected by the cation, and that the cations have more significant influence on the viscosity of the electrolytes per [0019], and teaches that the anion of the ionic liquid plays a substantial role in the electrochemical stability and consequently wideness of the potential window per [0020]. Thus, Shen teaches that since ionic liquids are basically composed of ions (cations and anions as cited above) that may undergo almost unlimited structural variations because of the easy preparation of a large variety of their components ([0019]) such that various kinds of ionic liquids can be used in the ionic liquid electrolyte ([0021]). Shen [0021] teaches the ionic liquid has a melting point less than 100°C, giving a suitable example of N-Butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide (Py14FSI) (see Shen [0021] as cited above, and Shen [0062] as further explained below). In the electrolyte, Shen further teaches inclusion of electrolyte salt wherein the ionic liquid and the electrolyte salt have the same anion ([0030]), listing exemplary lithium bis(fluorosulfonyl)imide (LiFSI) in [0030] (which is the same LiFSI electrolyte salt of Zhang [0008, 0083] as cited above), having the same bis(fluorosulfonyl)imide anion as listed in [0020] for the exemplary ionic liquid. Shen specifically teaches in [0031] toward enhanced solvation in high concentration electrolytes, e.g. > 3 M, can effectively stabilize the solvent molecules and mitigate anode and electrolyte degradation during extended cycling, giving the example of concentrated lithium bis(fluorosulfonyl) imide (LiFSI) in the electrolyte which showed remarkable stability against reduction by Li and enabled dendrite-free and extremely stable cycling. This teaching agrees with the 3 M to 6 M LiFSI concentration, and specifically 4 M, in DME taught in Zhang [0064, 0083] as cited above. Shen also teaches in [0028] that organic carbonates have excellent stability at negative potentials, and the presence of organic carbonates is able to extend the electrochemical stability of ionic liquids, listing 1,2-dimethoxyethane carbonates (DME) as an example of organic carbonate additive for use in the ionic liquid electrolyte. Shen [0029] teaches the additives can be present from at least 1 wt.% and no more than 20 wt.% as a weight percentage based on the total weight of the electrolyte. Shen [0062] specifically gives inventive examples mixing an ionic liquid with DME (4:1 by weight) and 4M LiFSI. Therefore, the amount of DME is 20 wt.% compared to 80 wt.% of ionic liquid. In Shen [0062], the ionic liquid of inventive Example 6 is Py14FSI used alongside the DME and LiFSI. 4M is the same concentration as 4M LiFSI within the inventive example of Zhang [0083] cited above.
The following chemical properties are used to calculate weight percentages based on the above prior art data:
As evidenced by “Chemical Book: 1,2-dimethoxyethane (DME)” the density of 1,2-dimethoxyethane (DME) is 0.867 g/mL and its molecular weight is 90.12 [units of 1 a.m.u. = 1 g/mol as known in the chemical arts] (see attached DME NPL at pg. 2). “Chemical Book: 1,2-dimethoxyethane (DME)” NPL further notes (see pg. 13 of attachment) that 1,2-dimethoxyethane is also known as glyme or monoglyme, and is widely used as a solvent for electrolyte of lithium batteries.
As evidenced by “Chemical Book: Lithium bis(fluorosulfonyl)imide”, the molecular weight of Lithium bis(fluorosulfonyl)imide (LiFSI) is 187.072 [units of 1 a.m.u. = 1 g/mol as known in the chemical arts] and its density is 1.052 g/cm3 (see attached LiFSI NPL at pg. 2). “Chemical Book: Lithium bis(fluorosulfonyl)imide” NPL further notes (see pg. 6 of attachment) that Lithium bis(fluorosulfonyl)imide is useful as electrolyte additive for lithium ion batteries.
As evidenced by Ramirez, the density of N-n-butyl-N-methylpyrrolidinium bis(fluorosulfonyl imide) [BMPYR][FSI] at Standard Ambient Temperature and Pressure (298.15K, 0.1MPa) is 1.307 g/cm3 (Ramirez Table 2 on pg. 3439).
As evidenced by Proionic, “1-Butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide” is synonymous with “N-Butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide”, “Bmpyr FSI”, and “PYR14 FSI” (see attached Proionic NPL at pg. 2 as cited above), and the molecular weight of such is 322.39 g/mol (see attached Proionic NPL at pg. 2).
Therefore, since Shen (in inventive Example 6 as cited above) teaches Py14FSI ionic liquid with DME (4:1 by weight) and 4M LiFSI, and Zhang (in the inventive example of [0083] cited above) also teaches 4 M LiFSI-DME as the liquid electrolyte, the following weight percentage calculations are performed using the above-evidences chemical properties of densities and molecular weights:
o
n
a
b
a
s
i
s
o
f
100
g
l
i
q
u
i
d
,
a
t
4
:
1
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i
g
h
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a
t
i
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y
14
F
S
I
t
o
D
M
E
:
100
g
=
80
g
P
y
14
F
S
I
+
20
g
D
M
E
a
n
d
:
0.023068
L
D
M
E
0.084277
L
t
o
t
a
l
l
i
q
u
i
d
=
27.37
v
o
l
%
D
M
E
,
o
f
l
i
q
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i
d
c
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m
p
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e
n
t
s
Examiner notes that 68.25 wt.% concentrated electrolyte falls within the instantly claimed range “greater than or equal to about 20 wt.% to less than or equal to about 99.5 wt.%”, and 31.75 wt.% ionic liquid falls within the instantly claimed range “greater than or equal to about 0.5 wt.% to less than or equal to about 80 wt.%”. In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exist (MPEP 214.05 I).
It would have been obvious, at the time of filing, for a person having ordinary skill in the art to modify the electrolyte of the anode-free battery of Zhang to also include an ionic liquid like that within the electrolyte of Shen (having the exemplary above-cited cation and anion and in the above-explained amounts) with the motivation of achieving improved the safety of the electrolytes due to fire prevention properties of ionic liquid, as taught toward by Shen. Also, the selection of a known material based on its suitability for its intended use supports a prima facie obviousness determination (MPEP 2144.07) and simple substitution of one known element for another to obtain predictable results supports a conclusion of obviousness (MPEP 2143 I B), such that using the Py14FSI + DME + LiFSI electrolyte of Shen in place of the DME + LiFSI electrolyte of Zhang would have been obvious.
Thus, the instant claim 19 is rendered obvious.
Claim(s) 11-13, 15, 18, and 20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Zhang et al. in view of Shen et al., as evidenced by “Chemical Book: 1,2-dimethoxyethane (DME)”, “Chemical Book: Lithium bis(fluorosulfonyl)imide”, Ramirez et al., and Proionic (all as cited and applied to claims 1, 14, 17, and 19 above), and further in view of Chang et al. (US 20190214672 A1).
Regarding claim 11, modified Zhang teaches the electrolyte of claim 1 above, but fails to teach: wherein the ionic liquid comprises a first anion and a second anion, the first and second anions independently selected from the group consisting of: hexafluoroarsenate, hexafluorophosphate, bis(fluorosulfonyl)imide (FSI), bis(trifluoromethanesulfonyl)imide (TFSI), perchlorate, tetrafluoroborate, cyclo-difluoromethane-1,1-bis(sulfonyl)imide (DMSI), bis(perfluoroethanesulfonyl)imide (BETI), bis(oxalate)borate (BOB), difluoro(oxalato)borate (DFOB), bis(fluoromalonato)boarate (BFMB), and combinations thereof.
Chang is analogous in the art of anodeless lithium metal battery (title, abstract) and teaches liquid electrolytes which include an ionic liquid and/or a polymer ionic liquid ([0054-0059]). Chang teaches that the use of an anode current collector without a planar lithium metal thin film, together with a composite electrolyte comprising at least one of lithium metal or a lithium metal alloy, and a liquid electrolyte, results in improved energy density and charge-discharge efficiency of a lithium metal battery (Chang [0033]). Chang teaches in [0053] the battery including both a first liquid electrolyte and a second liquid electrolyte, wherein compositions of the first liquid electrolyte and the second liquid electrolyte are different from each other and are independently selected in order to compensate for any electrochemical disadvantages of the anodeless lithium metal battery, such as high-voltage oxidation and electrolyte loss due to dendrite growth. Chang [0054] teaches said independent compositions can each independently include at least one of an ionic liquid and a polymer ionic liquid. Chang lists anion options in [0055, 0058-0059], which overlap those taught for the ionic liquid in Shen [0020-0021] as well as instant claim 11. Overlapping examples from Chang [0055], Shen [0020], and the instant claim include bis(fluorosulfonyl)imide, TFSI, tetrafluoroborate, and BETI.
It would have been obvious, at the time of filing, for a person having ordinary skill in the art to further modify the electrolyte of modified Zhang to include two different ionic liquids (i.e., with two different anions) independently selected in order to compensate for any electrochemical disadvantages of the anodeless lithium metal battery, such as high-voltage oxidation and electrolyte loss due to dendrite growth, as taught toward by Chang. Further, the selection of a known material based on its suitability for its intended use supports a prima facie obviousness determination (MPEP 2144.07) such that selecting two independent anions from the above-cited non-limiting examples would have been obvious.
Thus, the instant claim 11 is rendered obvious.
Regarding claim 12, modified Zhang teaches electrolyte of claim 11, wherein a molar ratio of the first anion to the second anion is greater than or equal to about 0.001:3 to less than or equal to about 3:0.001 (Example 1 in Chang [0106, 0108]: 3.5M first liquid electrolyte comprising FSI- anion, 0.4M second electrolyte comprising TFSI- anion – such that molar ratio of first:second anion = 3.5:0.4 = 1:0.114, which falls within the claimed range). When modifying the electrolyte in view of Chang to have two anions as cited above in the rejection of claim 11, it would have further been obvious to select a molar concentration of each as taught by Chang in order to achieve the desirable properties of Chang.
Regarding claim 13, modified Zhang teaches electrolyte of claim 11, wherein the first anion comprises bis(trifluoromethanesulfonyl)imide (TFSI) (Non-limiting examples of the anion include bis(trifluoromethylsulfonyl)imide (TFSI); Chang [0055] as applied to modified Zhang above), but fails to expliticly teach and the second anion comprises difluoro(oxalato)borate (DFOB).
However, Chang does teach in [0076] a lithium salt within the electrolyte can be LiDFOB (i.e., Li+ cathode and DFOB- anode), and Shen teaches in [0030] that the ionic liquid and the electrolyte salt have the same anion, also listing LiDFOB as a suitable electrolyte salt. Shen also teaches in [0020] that difluoro(oxalato)borate (DFOB−) is a suitable anode for ionic liquid within their electrolyte.
The selection of a known material based on its suitability for its intended use supports a prima facie obviousness determination (MPEP 2144.07) such that selecting DFOB as the second anion option within the ionic liquid of the electrolyte of modified Zhang would have been an obvious choice within the ambit of a person having ordinary skill in the art, in view of the teachings by Chang and Shen.
Thereby, claim 13 is rendered obvious.
Regarding claim 15, modified Zhang teaches the anode-free electrochemical cell of claim 14 above and teaches at least one of the positive current collector and the negative current collector is in contact with the electrolyte (bare anode current collector, the electrolyte and/or cathode serves as the source of the anode material that is formed during the charging process, the anode current collector is when in physical contact with the electrolyte in an operating voltage window of the battery; Zhang [0051-0052]) but fails to teach the positive electroactive material layer also comprises the electrolyte.
Zhang does teach in [0057] that the cathode includes a conductive additive which is stable with the electrolyte within the operation voltage window of the battery. Shen also teaches in [0055] a cathode includes one or more of the electroactive material in electrical contact with the electrolyte.
Chang is analogous in the art of anodeless lithium metal battery (title, abstract) and teaches liquid electrolytes which include an ionic liquid and/or a polymer ionic liquid ([0054-0059]). Chang teaches in [0040] a cathode that a cathode active material layer, which is disposed on the cathode current collector may, include a cathode active material and a second liquid electrolyte. Chang [0077] teaches that ions may freely migrate in the first liquid electrolyte or the second liquid electrolyte, and ion conductivity may be improved.
Since Zhang and Shen teach the cathode materials being conductive of lithium ions and being stable against electrolyte, a person having ordinary skill in the art would have further found it obvious in view of the teaching of Chang to modify the battery of modified Zhang to include a second liquid electrolyte within the cathode active material layer on the cathode current collector as taught by Chang (thus reading on “the positive electroactive material layer also comprises the electrolyte”) in order to allow for free migration of ions therethrough, thus improving lithium ion conductivity in the cathode.
Thereby, claim 15 is rendered obvious.
Regarding claim 18 and claim 20, modified Zhang teaches limitations of claims 17 and 19 above, but fails to teach: wherein the anion comprises a first anion and a second anion distinct from the first anion, wherein a molar ratio of the first anion to the second anion is greater than or equal to about 0.001:3 to less than or equal to about 3:0.001.
Chang is analogous in the art of anodeless lithium metal battery (title, abstract) and teaches liquid electrolytes which include an ionic liquid and/or a polymer ionic liquid ([0054-0059]). Chang teaches that the use of an anode current collector without a planar lithium metal thin film, together with a composite electrolyte comprising at least one of lithium metal or a lithium metal alloy, and a liquid electrolyte, results in improved energy density and charge-discharge efficiency of a lithium metal battery (Chang [0033]). Chang teaches in [0053] the battery including both a first liquid electrolyte and a second liquid electrolyte, wherein compositions of the first liquid electrolyte and the second liquid electrolyte are different from each other and are independently selected in order to compensate for any electrochemical disadvantages of the anodeless lithium metal battery, such as high-voltage oxidation and electrolyte loss due to dendrite growth. Chang [0054] teaches said independent compositions can each independently include at least one of an ionic liquid and a polymer ionic liquid. Chang lists anion options in [0055, 0058-0059], which overlap those taught for the ionic liquid in Shen [0020-0021], including bis(fluorosulfonyl)imide, TFSI, tetrafluoroborate, and BETI.
It would have been obvious, at the time of filing, for a person having ordinary skill in the art to further modify the electrolyte of modified Zhang to include two different ionic liquids (i.e., with two different anions) independently selected in order to compensate for any electrochemical disadvantages of the anodeless lithium metal battery, such as high-voltage oxidation and electrolyte loss due to dendrite growth, as taught toward by Chang. Further, the selection of a known material based on its suitability for its intended use supports a prima facie obviousness determination (MPEP 2144.07) such that selecting two independent anions from the above-cited non-limiting examples would have been obvious.
Further, Chang teaches a molar ratio of the first anion to the second anion is greater than or equal to about 0.001:3 to less than or equal to about 3:0.001 (Example 1 in Chang [0106, 0108]: 3.5M first liquid electrolyte comprising FSI- anion, 0.4M second electrolyte comprising TFSI- anion – such that molar ratio of first:second anion = 3.5:0.4 = 1:0.114, which falls within the claimed range). Therefore, when modifying the electrolyte in view of Chang to have two anions as cited above, it would have further been obvious to select a molar concentration of each as taught by Chang in order to achieve the desirable properties of Chang.
Thereby, all limitations of claims 18 and 20 are rendered obvious.
Relevant Prior Art
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Chang et al. (US 20190214672 A1, cited in 35 USC 103 section above) is analogous in the art of anodeless lithium metal battery (title, abstract) and teaches liquid electrolytes which can include an ionic liquid and/or a polymer ionic liquid ([0054-0059]). Chang teaches that the use of an anode current collector without a planar lithium metal thin film, together with a composite electrolyte comprising at least one of lithium metal or a lithium metal alloy, and a liquid electrolyte, results in improved energy density and charge-discharge efficiency of a lithium metal battery (Chang [0033]), such that an anodeless lithium metal battery includes: a cathode including a cathode current collector and a cathode active material layer on the cathode current collector; an anode current collector on the cathode; and a composite electrolyte between the cathode and the anode current collector (Chang [0008]). Chang [0053] teaches a first liquid electrolyte included in the composite electrolyte, which can be the ionic liquids examples of Change [0054-0059] as cited above. Chang [0055] teaches exemplary cations can be an ammonium cation such as triethyl ammonium (which is an exemplary cation of Zhang [0063] as cited above), used in a combination comprising at least one cation and an anion such as exemplary bis(trifluoromethylsulfonyl)imide (TFSI) (see Chang [0055]). In the compound electrolyte, Chang further teaches examples of solvents (such as 1,2-dimethoxyethane selected as a glyme compound in the first solvent of the first liquid electrolyte, per Chang [0066-0067]) and lithium salts (such as lithium bis(fluorosulfonyl)imide (LiFSI), Chang [0076]) to be used together with the above-cited ionic liquid.
Zhang et al. (cited in 35 USC 103 section above) as evidenced by “Chemical Book: 1,2-dimethoxyethane (DME)” (cited in 35 USC 103 section above) and “Chemical Book: Lithium bis(fluorosulfonyl)imide” (cited in 35 USC 103 section above) teaches:
As evidenced by “Chemical Book: 1,2-dimethoxyethane (DME)” the density of 1,2-dimethoxyethane (DME) is 0.867 g/mL and its molecular weight is 90.12 [units of 1 a.m.u. = 1 g/mol as known in the chemical arts] (see attached DME NPL at pg. 2). “Chemical Book: 1,2-dimethoxyethane (DME)” NPL further notes (see pg. 13 of attachment) that 1,2-dimethoxyethane is also known as glyme or monoglyme, and is widely used as a solvent for electrolyte of lithium batteries.
As evidenced by “Chemical Book: Lithium bis(fluorosulfonyl)imide”, the molecular weight of Lithium bis(fluorosulfonyl)imide (LiFSI) is 187.072 [units of 1 a.m.u. = 1 g/mol as known in the chemical arts] and its density is 1.052 g/cm3 (see attached LiFSI NPL at pg. 2). “Chemical Book: Lithium bis(fluorosulfonyl)imide” NPL further notes (see pg. 6 of attachment) that Lithium bis(fluorosulfonyl)imide is useful as electrolyte additive for lithium ion batteries.
Therefore based on 4 M LiFSI-DME example in Zhang [0083] (as cited in above rejection), the following Wt.% Calculations can be performed:
4
M
L
i
F
S
I
∙
D
M
E
=
4
m
o
l
L
i
F
S
I
1
L
s
o
l
u
t
i
o
n
o
f
L
i
F
S
I
+
D
M
E
→
250.303
g
D
M
E
998.591
g
t
o
t
a
l
=
25.1
w
t
.
%
D
M
E
p
e
r
1
L
s
o
l
u
t
i
o
n
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Jessie Walls-Murray whose telephone number is (571)272-1664. The examiner can normally be reached M-F, typically 10-4.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Matthew Martin can be reached at (571) 270-7871. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/JESSIE WALLS-MURRAY/Primary Examiner, Art Unit 1728