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 .
Claim Objections
Claim 1 is objected to because of the following informalities. The phrase "…comprising: a compound containing fluorine element, lanthanum element, an alkaline earth metal element, and an alkali metal element…" lacks the required indefinite articles before "fluorine element" and "lanthanum element." Applicant is requested to amend the claim language to introduce the elements with the indefinite article "a" or "an", for example: "...a compound containing a fluorine element, a lanthanum element, an alkaline earth metal element, and an alkali metal element...," if that is what is intended for the scope of the claim.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless – (a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1-3, 10, and 13 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Mellors (EP0055135A2).
Regarding claim 1, Mellors teaches a fluoride ion conductive material for a solid-state electrolyte (claim 1; pg. 3 lines 4-21) comprising a compound containing fluorine element, lanthanum element, an alkaline earth metal element, and an alkali metal element, the compound being represented by compositional formula La0.9025Sr0.0475Li0.05F2.8525. Specifically, Mellors discloses a composition for a solid-state cell electrolyte comprising LaF3 (90.25 mole%) - SrF2 (4.75 mole%) - LiF (5.00 mole%) (pg. 5 lines 21-28), which is equivalent to La0.9025Sr0.0475Li 0.05F2.8525 because:
La:
90.25
100
= 0.9025
Sr:
4.75
100
= 0.0475
Li:
5.00
100
= 0.0500,
and to calculate the amount of F:
from LaF3: 0.9025 x 3 = 2.7075
from SrF2: 0.0475 x 2 = 0.0950
from LiF: 0.0500 x 1 = 0.05.
Lastly, adding all of the F amounts together (2.7075 + 0.0950 + 0.0500 = 2.8525) results in the compositional formula La0.9025Sr0.0475Li0.05F2.8525. Thus, the solid-state electrolyte composition of Mellors satisfies the claimed requirements of formula (1):
La1-x-yM1xM2yF3-x-2y
such that M1 is at least one element (Sr) selected from alkaline earth metal elements, M2 is at least one element (Li) selected from alkali metal elements, and x=0.0475 which satisfies 0 < x ≤ 0.3, y=0.0500 which satisfies 0 < y ≤ 0.2, x + y = 0.0975 which satisfies 0 < x + y ≤ 0.4, for La, 1-x-y is 0.9025, and for F, 3-x-2y is 2.8525.
Regarding claim 2, Mellors discloses all limitations of claim 1 as described above, and further discloses x satisfies 0 < x ≤ 0.1. Specifically, in the compositional formula La0.9025Sr0.0475Li0.05F2.8525 discussed in claim 1, M1 is Sr and x = 0.0475, which satisfies the claimed requirement of 0 < x ≤ 0.1.
Regarding claim 3, Mellors discloses all limitations of claim 1, and further discloses y satisfies 0 < y ≤ 0.1. Specifically, in the compositional formula La0.9025Sr0.0475Li0.05F2.8525 discussed in claim 1, M2 is Li and y = 0.05, which satisfies the claimed requirement of 0 < y ≤ 0.1.
Regarding claim 13, Mellors teaches a fluoride shuttle battery (claim 1; pg. 3 lines 4-21) comprising a positive electrode (cathode; claim 7) and a negative electrode (anode; claim 7).
Regarding the limitation, “…and an electrolyte layer disposed between the positive electrode and the negative electrode,” Mellors inherently teaches this limitation because Mellors discloses a fluoride shuttle battery comprising a cathode, an anode, as mentioned above, and a solid electrolyte layer (claim 1; pg. 3 lines 4-21; pg. 13, “Example XIII”, lines 1-10). It is well established in the art that an operable battery requires the electrolyte to be located between the electrodes to facilitate ion transport. Therefore, the solid electrolyte inherently forms a layer disposed between the positive and negative electrodes, meeting the structural limitations of the claim.
Regarding the limitation, “…and an electrolyte layer disposed between the positive electrode and the negative electrode, wherein at least one selected from the group consisting of the positive electrode, the negative electrode, and the electrolyte layer comprises the fluoride ion conductive material according to claim 1,” Mellors teaches a fluoride ion conductive material for a solid-state electrolyte (claim 1; pg. 3 lines 4-21) comprising a compound containing a fluorine element, a lanthanum element, an alkaline earth metal element, and an alkali metal element, the compound being represented by the compositional formula La0.9025Sr0.0475Li0.05F2.8525, as described above in the rejection for claim 1. To reiterate, Mellors discloses a composition for a solid-state cell electrolyte comprising LaF3 (90.25 mole%) - SrF2 (4.75 mole%) - LiF (5.00 mole%) (pg. 5 lines 21-28), which is equivalent to La0.9025Sr0.0475Li 0.05F2.8525 because:
La:
90.25
100
= 0.9025
Sr:
4.75
100
= 0.0475
Li:
5.00
100
= 0.05,
and to calculate the amount of F:
from LaF3: 0.9025 x 3 = 2.7075
from SrF2: 0.0475 x 2 = 0.0950
from LiF: 0.05 x 1 = 0.05.
Therefore, adding all of the F amounts together (2.7075 + 0.0950 + 0.05 = 2.8525) results in the compositional formula La0.9025Sr0.0475Li0.05F2.8525. Thus, the solid-state electrolyte composition of Mellors satisfies the claimed requirements of formula (1) in claim 1:
La1-x-yM1xM2yF3-x-2y
such that M1 is at least one element (Sr) selected from alkaline earth metal elements, M2 is at least one element (Li) selected from alkali metal elements, and x=0.0475 which satisfies 0 < x ≤ 0.3, y=0.05 which satisfies 0 < y ≤ 0.2, x + y = 0.0975 which satisfies 0 < x + y ≤ 0.4, for La, 1-x-y is 0.9025, and for F, 3-x-2y is 2.8525.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
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.
Claims 4-12 are rejected under 35 U.S.C. 103 as being unpatentable over Mellors (EP0055135A2).
Regarding claim 4, Mellors discloses all limitations of claim 1, including a fluoride ion conductive material composition based on cerium- or lanthanum-fluoride electrolyte systems having alkaline earth metal and alkali metal constituents (claim 1). Mellors does not explicitly disclose a lanthanum-based fluoride ion conductive material composition for an electrolyte having the alkaline earth metal (M1) including Sr and the alkali metal (M2) including Na, as claimed.
However, Mellors discloses a fluoride ion conductive electrolyte composition such as 85.71LaF3 – 9.52SrF2 – 4.77LiF (pg. 10, Table IV), equating to La0.8571Sr0.0952Li0.0477F2.8094 which satisfies the limitations of 0 < x ≤ 0.3, 0 < y ≤ 0.2, and 0 < x + y ≤ 0.4 from claim 1, thereby teaching strontium (Sr) as an alkaline earth metal constituent in a lanthanum-based fluoride ion conductive electrolyte. Mellors also discloses the electrolyte composition 89CeF3 – 6SrF2 – 5NaF (pg. 9, Table III, line 6), equating to Ce0.890Sr0.0600Na0.0500F2.84 which satisfies the limitations of 0 < x ≤ 0.3, 0 < y ≤ 0.2, and 0 < x + y ≤ 0.4 from claim 1, thereby teaching sodium (Na) as an alkali metal constituent in a strontium-containing fluoride ion conductive electrolyte. Further, Mellors teaches the use of both lanthanum (La) and cerium (Ce) trifluorides as fluoride ion conductors for solid-state cell electrolytes (claim 1), and discloses that each of these materials performs similarly and presents the identical problem of low conductance (pg. 3 lines 22-31), requiring the same combination of alkaline earth metal compounds (such as Sr) and alkali metal compounds (such as Na) as disclosed in the specific La and Ce examples above, to achieve functional solid electrolytes. Since Mellors expressly equates the properties and functional behavior of lanthanum and cerium trifluorides in the disclosed electrolyte system, it would have been obvious to one of ordinary skill in the art to substitute lanthanum for cerium, or vice versa, to achieve the La1-x-yM1xM2yF3-x-2y composition required by claim 1.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to include Sr as an alkaline earth metal constituent (M1) and Na as an alkali metal constituent (M2) in the lanthanum (La)-based fluoride ion conductive electrolyte of Mellors, because Mellors expressly teaches both Sr and Na constituents for use in the same class of fluoride ion conductive electrolyte compositions. The selection of Sr and Na from the finite number of known and interchangeable electrolyte constituents taught by Mellors would represent the use of known alternatives for their disclosed purpose and would have predictably resulted in a fluoride ion conductive material for a solid-state electrolyte having M1 including Sr and M2 including Na, in the form of general formula (1), as claimed. Thus, the selection would have resulted in a predictable variation within the disclosed electrolyte system.
Regarding claim 5, Mellors teaches all limitations of claim 4, including a lanthanum (La)-based fluoride ion conductive material composition for an electrolyte that includes Sr as an alkaline earth metal constituent (M1) and Na as an alkali metal constituent (M2), as described above. Mellors does not explicitly disclose a fluoride ion conductive material composition for an electrolyte wherein the compositional formula is La1-x-ySrxNayF3-x-2y such that x satisfies 0 < x ≤ 0.05.
However, Mellors further teaches that the mole ratio of cerium (Ce) or lanthanum (La) to alkaline earth metal is in the range of 7:1 to 99:1 and preferably 15:1 to 25:1 such that a range below 7:1 may not provide increased conductivity of the trifluoride composition, and ratios above 99:1 are similarly ineffective, with preferred conductivities of at least 10-5
Ω
c
m
and more preferably above 10-4
Ω
c
m
(pg. 4 lines 5-8 and 14-26). Thus, Mellors establishes that alkaline earth metal content is a result-effective variable affecting electrolyte performance within the disclosed electrolyte system. Accordingly, Mellors provides guidance that electrolyte performance depends on optimization of alkaline earth metal content within the disclosed ranges.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to optimize the amount of Sr within the electrolyte composition by selecting a value of x within the range taught and suggested by Mellors in order to obtain desired conductivity characteristics. Selection of a value of x within the claimed range of 0 < x ≤ 0.05 represents routine optimization of a result-effective variable (i.e. alkaline earth metal content) and would have yielded predictable electrolyte properties absent evidence of criticality or unexpected results. Accordingly, the composition La1-x-ySrxNayF3-x-2y, wherein 0 < x ≤ 0.05 (as required by claim 5) and 0 < y ≤ 0.2 (as required by claim 1) such that 0 < x + y ≤ 0.4, would have been an obvious variation of the electrolyte compositions disclosed by Mellors.
Regarding claim 6, Mellors teaches all limitations of claim 5, including a lanthanum (La)-based fluoride ion conductive material composition for an electrolyte that includes Sr as an alkaline earth metal constituent (M1) and Na as an alkali metal constituent (M2), as described above. Mellors does not explicitly disclose a fluoride ion conductive material composition for an electrolyte wherein the compositional formula is La1-x-ySrxNayF3-x-2y such that y satisfies 0 < y ≤ 0.04.
However, Mellors further teaches that alkali metal compounds are present in an amount of about 1 to 15 mol% of the electrolyte composition and more preferably about 3 to 7 mol% (pg. 4 lines 27-30), and that such alkali metal compounds function as sintering or binding aids that improve grain boundary conductance (pg. 5 lines 1-8); thus, Mellors establishes alkali metal content as a result-effective variable affecting electrolyte processing and performance.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to include Na as an alkali metal constituent (M2) in the lanthanum-based fluoride ion conductive electrolyte of Mellors for the reasons set forth in the rejection of claim 4 above, and to optimize the amount of Na within the electrolyte composition by selecting a value of y within the range taught and suggested by Mellors in order to obtain the desired conductivity characteristics. Selection of a value of y within the claimed range of 0 < y ≤ 0.04 would represent routine optimization of a known result-effective variable (i.e. alkali metal content) and would have yielded predictable electrolyte properties absent evidence of criticality or unexpected results. Accordingly, the composition La1-x-ySrxNayF3-x-2y, wherein 0 < x ≤ 0.05 (as required by claim 5) and 0 < y ≤ 0.04 (as required by claim 6) such that 0 < x + y ≤ 0.4, would have been an obvious variation of the electrolyte compositions disclosed by Mellors.
Regarding claim 7, Mellors discloses all limitations of claim 1, including a fluoride ion conductive material composition based on cerium- or lanthanum-fluoride electrolyte systems having alkaline earth metal and alkali metal constituents (claim 1). Mellors does not explicitly disclose a fluoride ion conductive material composition for an electrolyte wherein the alkaline earth metal (M1) includes Ba and the alkali metal (M2) includes Na, as claimed.
However, Mellors discloses the electrolyte composition 85.71LaF3 – 9.52BaF2 – 4.77LiF (pg. 10, Table IV), equating to La0.8571Ba0.0952Li0.0477F2.8094 which satisfies the limitations of 0 < x ≤ 0.3, 0 < y ≤ 0.2, and 0 < x + y ≤ 0.4 from claim 1, and the electrolyte composition 85.5CeF3 – 9.50BaF2 – 5.00LiF (pg. 10, Table IV), equating to Ce0.8550Ba0.0950Li0.0500F2.805 which satisfies the limitations of 0 < x ≤ 0.3, 0 < y ≤ 0.2, and 0 < x + y ≤ 0.4 from claim 1, thereby teaching barium (Ba) as an alkaline earth metal constituent in both cerium- and lanthanum-based fluoride ion conductive electrolyte systems. Mellors additionally discloses the electrolyte composition 89CeF3 – 6SrF2 – 5NaF (pg. 9, Table III), which equates to Ce0.890Sr0.0600Na0.0500F2.84, thereby teaching sodium (Na) as an alkali metal constituent in a fluoride ion conductive electrolyte system comprising an alkaline earth metal constituent. Mellors further discloses that suitable alkali metal constituents include lithium, potassium, rubidium, and related compounds such as LiF, Li2SO4, RbCl, KF and RbF (claim 6), and that alkaline earth metal constituents including Li, Sr, Ba, Ca, Mg, Ce, La, or cerium or lanthanum-based alloy anodes (pg. 13 lines 11-17) are suitable for use in the disclosed electrolyte system.Further, Mellors teaches the use of both lanthanum (La) and cerium (Ce) trifluorides as fluoride ion conductors for solid-state cell electrolytes (claim 1), and discloses that each of these materials performs similarly and presents the identical problem of low conductance (pg. 3 lines 22-31), requiring the same combination of alkaline earth metal compounds (such as Ba) and alkali metal compounds (such as Na) as disclosed in the specific La and Ce examples above, to achieve functional solid electrolytes. Since Mellors expressly equates the properties and functional behavior of lanthanum and cerium trifluorides in the disclosed electrolyte system, it would have been obvious to one of ordinary skill in the art to substitute lanthanum for cerium, or vice versa, to achieve the La1-x-yM1xM2yF3-x-2y composition required by claim 1.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to include Ba as an alkaline earth metal constituent (M1) and Na as an alkali metal constituent (M2) in the lanthanum (La)-based fluoride ion conductive electrolyte of Mellors, because Mellors expressly teaches both barium- and sodium-containing compositions within the same fluoride ion conductive electrolyte framework and identifies both Ba and Na as suitable components for their respective roles. The selection of Ba and Na from the finite number of known and interchangeable electrolyte constituents taught by Mellors would have represented the use of known alternatives for their disclosed purpose and would have predictably resulted in a fluoride ion conductive material for an electrolyte having M1 including Ba and M2 including Na, as claimed. Thus, the selection would have resulted in a predictable variation within the disclosed electrolyte system.
Regarding claim 8, Mellors teaches all limitations of claim 7, including a lanthanum (La)-based fluoride ion conductive electrolyte material composition that includes Ba as an alkaline earth metal constituent (M1) and Na as an alkali metal constituent (M2), as described above. Mellors does not explicitly disclose a fluoride ion conductive material composition for an electrolyte wherein the compositional formula is La1-x-yBaxNayF3-x-2y such that x satisfies 0 < x ≤ 0.05.
However, Mellors further teaches that the mole ratio of cerium (Ce) or lanthanum (La) to alkaline earth metal is in the range of 7:1 to 99:1 and preferably 15:1 to 25:1 such that a range below 7:1 may not provide increased conductivity of the trifluoride composition and ratios above 99:1 are similarly ineffective, with preferred conductivities of at least 10-5
Ω
c
m
and more preferably above 10-4
Ω
c
m
(pg. 4 lines 5-8 and 14-26), thereby establishing that alkaline earth metal content is a result-effective variable affecting electrolyte performance. Accordingly, Mellors provides guidance that electrolyte performance depends on optimization of alkaline earth metal content within the disclosed ranges. Mellors further discloses working electrolyte compositions including 85.71LaF3 – 9.52BaF2 – 4.77LiF (pg. 10, Table IV), equivalent to La0.8571Ba0.0952Li0.0477F2.8094, and 85.5CeF3 – 9.50BaF2 – 5.00LiF (pg. 10, Table IV), equivalent to Ce0.8550Ba0.0950Li0.0500F2.805, which further demonstrates that barium-containing compositions are suitable for use within the disclosed electrolyte system.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to optimize the amount of Ba within the electrolyte composition by selecting a value of x within the range taught and suggested by Mellors in order to obtain desired conductivity characteristics. Selection of a value of x within the claimed range of 0 < x ≤ 0.05 represents the routine optimization of a result-effective variable (i.e. alkaline earth metal content) and would have yielded predictable electrolyte properties absent evidence of criticality or unexpected results. Accordingly, the composition La1-x-yBaxNayF3-x-2y, wherein 0 < x ≤ 0.05 (as required by claim 8) and 0 < y ≤ 0.2 (as required by claim 1) such that 0 < x + y ≤ 0.4, would have been an obvious variation of the electrolyte compositions disclosed by Mellors.
Regarding claim 9, Mellors teaches all limitations of claim 8 as described above, including fluoride ion conductive electrolyte compositions including Ba as an alkaline earth metal constituent (M1) and Na as an alkali metal constituent (M2). Mellors does not explicitly disclose a fluoride ion conductive material composition for an electrolyte wherein the compositional formula is La1-x-yBaxNayF3-x-2y such that y satisfies 0 < y ≤ 0.04.
However, Mellors further teaches that alkali metal compounds are present in an amount of about 1 to 15 mol % of the electrolyte composition and more preferably about 3 to 7 mol % (pg. 4 lines 27-30), and that such alkali metal compounds function as sintering or binding aids that improve grain boundary conductance (pg. 5 lines 1-8); thus, Mellors establishes alkali metal content as a result-effective variable affecting electrolyte processing and performance. Mellors additionally discloses the electrolyte composition 89CeF3 – 6SrF2 – 5NaF (pg. 9, Table III, line 6), which equates to Ce0.890Sr0.0600Na0.0500F2.84, further demonstrating that sodium-containing compositions are suitable for use within the disclosed electrolyte system.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to include Na as an alkali metal constituent (M2) in the lanthanum-based fluoride ion conductive electrolyte of Mellors for the reasons set forth in the rejection of claim 7 above, and to optimize the amount of Na within the electrolyte composition by selecting a value of y within the range taught and suggested by Mellors in order to obtain the desired conductivity characteristics. Selection of a value of y within the claimed range of 0 < y ≤ 0.04 represents the routine optimization of a known result-effective variable (i.e. alkali metal content) and would have yielded predictable electrolyte properties absent evidence of criticality or unexpected results. Accordingly, the composition La1-x-yBaxNayF3-x-2y, wherein 0 < x ≤ 0.05 (as required by claim 8) and 0 < y ≤ 0.04 (as required by claim 9) such that 0 < x + y ≤ 0.4, would have been an obvious variation of the electrolyte compositions disclosed by Mellors.
Regarding claim 10, Mellors discloses all limitations of claim 1, including a fluoride ion conductive material composition based on cerium- or lanthanum-fluoride electrolyte systems having alkaline earth metal and alkali metal constituents (claim 1). Mellors further teaches the composition for a solid-state electrolyte wherein an alkaline earth metal M1 may be selected to include Ca (claim 8; pg. 13, lines 11-16) and an alkali metal M2 may be selected to include K (claim 5, alkali metal compound KF may be selected). Mellors does not explicitly disclose a lanthanum-based fluoride ion conductive material composition for an electrolyte having the alkaline earth metal (M1) including Sr and the alkali metal (M2) including Na in the form of general formula (1), as required by claim 1.
However, Mellors discloses working electrolyte examples where the electrolyte is represented by compositions such as 85.50CeF3 – 9.50CaF2 – 5.00KF (pg. 10, Table IV), equivalent to Ce0.8550Ca0.0950K0.0500F2.805 which satisfies the limitations of 0 < x ≤ 0.3, 0 < y ≤ 0.2, and 0 < x + y ≤ 0.4 from claim 1, thus teaching calcium (Ca) as an alkaline earth metal constituent (M1) and potassium (K) as an alkali metal constituent (M2). Mellors additionally discloses La-based electrolyte compositions comprising alkaline earth metal fluorides such as CaF2 (pg. 10, Table IV, 85.71LaF3 – 9.52CaF2 – 4.77LiF equivalent to La0.8571Ca0.0952Li0.0477F2.8094 which satisfies the limitations of 0 < x ≤ 0.3, 0 < y ≤ 0.2, and 0 < x + y ≤ 0.4 from claim 1), and that La-based electrolyte compositions may comprise alkali metal fluorides such as LiF or KF (claims 1 and 5), further demonstrating that Ca and K are suitable metal constituents for their respective metal roles in the disclosed fluoride ion conductive electrolyte. Further, Mellors teaches the use of both lanthanum (La) and cerium (Ce) trifluorides as fluoride ion conductors for solid-state cell electrolytes (claim 1), and discloses that each of these materials performs similarly and presents the identical problem of low conductance (pg. 3 lines 22-31), requiring the same combination of alkaline earth metal compounds (such as Ca) and alkali metal compounds (such as K) as disclosed in the specific La and Ce examples above, to achieve functional solid electrolytes. Since Mellors expressly equates the properties and functional behavior of lanthanum and cerium trifluorides in the disclosed electrolyte system, it would have been obvious to one of ordinary skill in the art to substitute lanthanum for cerium, or vice versa, to achieve the La1-x-yM1xM2yF3-x-2y composition required by claim 1.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to include Ca as an alkaline earth metal constituent (M1) and K as an alkali metal constituent (M2) in the lanthanum (La)-based fluoride ion conductive electrolyte of Mellors, because Mellors expressly teaches both Ca and K constituents for use in the same class of fluoride ion conductive electrolyte compositions. The selection of Ca and K from the finite number of known and interchangeable electrolyte constituents taught by Mellors would represent the use of known alternatives for their disclosed purpose and would have predictably resulted in a fluoride ion conductive material for a solid-state electrolyte having M1 including Ca and M2 including K, in the form of general formula (1), as claimed. Thus, the selection would have resulted in a predictable variation within the disclosed electrolyte system.
Regarding claim 11, Mellors discloses all features of claim 10, including fluoride ion conductive material compositions for an electrolyte based on cerium- or lanthanum-fluoride systems having alkaline earth metal and alkali metal components, including compositions wherein an alkaline earth metal element (M1) includes Ca and an alkali metal constituent (M2) includes K, as described above. Mellors does not explicitly disclose an electrolyte wherein the compositional formula is La1-x-yCaxKyF3-x-2y such that x satisfies 0 < x ≤ 0.05.
However, Mellors discloses working electrolyte composition examples such as 85.50CeF3 – 9.50CaF2 – 5.00KF (pg. 10, Table IV) as mentioned in the rejection for claim 10 above, which teaches a fluoride ion conductive electrolyte including calcium (Ca) as an alkaline earth metal constituent (M1) and potassium (K) as an alkali metal constituent (M2). Mellors additionally discloses La-based electrolyte compositions comprising alkaline earth metal fluorides such as CaF2 (pg. 10, Table IV, 85.71LaF3 – 9.52CaF2 – 4.77LiF) as mentioned in the rejection for claim 10 above, and that La-based electrolyte compositions may comprise alkali metal fluorides such as LiF or KF (claims 1 and 5), further demonstrating that Ca and K are suitable metal constituents for their respective metal roles in the disclosed fluoride ion conductive electrolyte.
Mellors also teaches that the alkaline earth metal component is preferably present such that the mole ratio of cerium (Ce) or lanthanum (La) to alkaline earth metal is in the range of 7:1 to 99:1 and preferably 15:1 to 25:1 such that a range below 7:1 may not provide increased conductivity of the trifluoride composition and ratios above 99:1 are similarly ineffective, with preferred conductivities of at least 10-5
Ω
c
m
and more preferably above 10-4
Ω
c
m
(pg. 4 lines 5-8 and 14-26), thereby establishing that alkaline earth metal content is a result-effective variable affecting electrolyte performance within the disclosed electrolyte system. Accordingly, Mellors provides guidance that electrolyte performance depends on optimization of alkaline earth metal content within the disclosed ranges.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to optimize the amount of Ca within the electrolyte composition by selecting a value of x within the range taught and suggested by Mellors in order to obtain desired conductivity characteristics. Selection of a value of x within the claimed range of 0 < x ≤ 0.05 represents the routine optimization of a result-effective variable (i.e. alkaline earth metal content) and would have yielded predictable electrolyte properties absent evidence of criticality or unexpected results. Accordingly, the composition La1-x-yCaxKyF3-x-2y, wherein 0 < x ≤ 0.05 (as required by claim 11) and 0 < y ≤ 0.2 (as required by claim 1) such that 0 < x + y ≤ 0.4, would have been an obvious variation of the electrolyte compositions disclosed by Mellors.
Regarding claim 12, Mellors teaches all features of claim 11, including that fluoride ion conductive electrolyte compositions based on a cerium- or lanthanum-fluoride system may comprise alkali metal (M2) fluorides such as LiF or KF (claims 1 and 5). Mellors does not explicitly disclose an electrolyte wherein the compositional formula is La1-x-yCaxKyF3-x-2y such that y satisfies 0 < y ≤ 0.02.
However, Mellors further teaches that alkali metal compounds are present in an amount of about 1 to 15 mol % of the electrolyte composition and more preferably about 3 to 7 mol % (pg. 4 lines 27-30), and that such alkali metal compounds function as sintering or binding aids that improve grain boundary conductance (pg. 5 lines 1-8); thus, Mellors establishes alkali metal content as a result-effective variable affecting electrolyte processing and performance.
Therefore, it would have been obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to optimize the amount of K within the electrolyte composition by selecting a value of y within the range taught and suggested by Mellors in order to obtain the desired conductivity characteristics. Selection of a value of y within the claimed range of 0 < y ≤ 0.02 represents the routine optimization of a known result-effective variable (i.e. alkali metal content) and would have yielded predictable electrolyte properties absent evidence of criticality or unexpected results. Accordingly, the composition La1-x-yCaxKyF3-x-2y, wherein 0 < x ≤ 0.05 (as required by claim 11) and 0 < y ≤ 0.02 (as required by claim 12) such that 0 < x + y ≤ 0.4, would have been an obvious variation of the electrolyte compositions disclosed by Mellors.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
Ando (JP2003229142A): appears to disclose an invention relating to a solid electrolyte comprising a compound containing fluorine, lanthanum, alkaline earth metal, and alkali metal elements.
Komori (EP3506410A1): appears to disclose a fluoride ion conductor for a secondary battery electrolyte comprising potassium, at least one alkaline earth metal selected from the group consisting of calcium, barium, and strontium, and fluorine.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALEXIS R OSTWALT whose telephone number is (571)272-8650. The examiner can normally be reached Mon-Fri 7:30am-5pm.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Marla McConnell can be reached at 5712707692. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/A.R.O./Examiner, Art Unit 1789
/MARLA D MCCONNELL/Supervisory Patent Examiner, Art Unit 1789
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