DETAILED ACTION
Notice of Pre-AIA or AIA Status
1. The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
2. A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 17 March 2026 has been entered.
Response to Amendments
3. The applicant’s amendment dated 17 March 2026 has been entered into the record. Claims 1, 23, and 29 have been amended. Claim 19 was previously cancelled by the applicant. Claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 23, 24, 25, 26, 27, 28, 29, 30, 31, and 32 are currently pending and under examination. The examiner finds that no new matter was added in submitted amendment and the applicant’s reply is fully responsive.
Information Disclosure Statement
4. The information disclosure statements (IDS) submitted on 26 November 2025 has been entered into the record and all references on said IDS form was considered.
Claim Rejections - 35 USC § 112
5. The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
6. Claim 15 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 15 recites the ratio of 160 mg of platinum black, 10.1 mg of cerium hydroxide, and 80 g ionomer.” It is unclear if this limitation is requiring of the specific weight lists in the claim limitation or it the language is meant to represent a normalized ratio. The claim will be interpreted to be at least inclusive of the aforementioned possibilities.
Claim Rejections - 35 USC § 103
7. 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.
8. 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.
9. Claims 1, 2, 3, 4, 5, 11, 12, 17, 18, and 31 are rejected under 35 U.S.C. 103 as being obvious over Lewinski et al. in view of Trogadas et al.
Lewinski et al. (US Pub. No. 2020/0102660 A1 – previously presented) is directed toward water electrolyzers comprising a recombination layer (Title and Abstract). Trogadas et al. (“Platinum supported on CeO2 effectively scavenges free radicals within the electrolyte of an operating fuel cell,” Chem. Comm. 2011, 47, 11549-11551 – previously presented) is directed at radical scavenging in operating fuel cells (pg. 11549: title).
Regarding Claim 1, Lewinski et al. discloses a method comprising: providing a first layer membrane (element 222 in LEWINSKI-FIG. 2B) having a first thickness (Table 3: Ex. 7 - Layer 2 with 100-micron thickness) providing a second layer membrane (element 221 in LEWINSKI-FIG. 2B) having a thickness less than the first thickness (Table 3: Ex. 7 - Layer 1 with 25-micron dried film thickness and ¶133). Lewinski et al. further teaches that the second layer comprises a platinum catalyst (e.g.: Pt/Pt oxide nanostructured thin film catalyst supported on perylene whiskers in Table 1 and Table 3: Ex. 7 and ¶133) and the first layer membrane does not contain any catalyst (Table 3: Ex. 7 and ¶133). Lewinski et al. discloses the “Layer 2” membrane composition as being free of platinum in ¶118 for a 50-micrometer thick polymeric perfluorosulfonic acid proton exchange membrane and in ¶133 for a 100-micrometer thick polymeric perfluorosulfonic acid proton exchange membrane in Ex. 7. Lewinski et al. also teaches an exchange membrane having an interface between the first layer membrane and the second layer membrane in the lamination procedure in Ex. 7 (¶133) and depicted in LEWINSKI-FIG. 2B between element 222 and elements 221. Lewinski et al. discloses in ¶104, the formation of the full catalyst-coated membrane (CCM) which is analogous to the membrane electrode assembly (MEA) of the present application. The full CCM has an Ir-based catalyst as the anode electrode and Pt-based catalyst as the cathode electrode which were attached to the exchange membrane using lamination (¶104).
Lewinski et al. discloses the catalyst layer comprising Pt/Pt oxide nanostructured thin film catalyst supported on perylene whiskers, but does not explicitly disclose nanoparticle catalyst dispersed throughout the ionomer layer. Lewinski et al. indicates that water electrolyzers membrane electrode assemblies that are similar to the proton exchange membranes used in fuel cells (¶2) meaning that one of ordinary skill in the art would be motivated to investigate fuel cell membranes for teachings relevant to the water electrolyzers.
Trogadas et al. teaches the addition of nanoparticulate platinum supported on CeO2 dispersed throughout the thickness of the ionomer layer (e.g.: Nafion) (pg. 11550: last paragraph left side and TEM image in Fig. 2). Trogadas et al. further indicates that the ionic conductivity significantly increases when the composite layer is 2 wt.% Pt on cerium oxide in a Nafion layer (pg. 11550: Fig. 3) meaning the electrochemical cell will be more efficient. Moreover, Trogadas et al. indicates evaluated the electrochemical performance of fuel cells that had low H2 crossover (ESI pg. 2-3: MEA testing - Performance and durability), which was also a focused of Lewinski et al. (reducing hydrogen crossover which lowers efficiency). The composite electrode with 2% Pt and CeO2 had the best electrochemical performance (pg. 11551: Fig. 5). Another benefit of the presence of CeO2 also reduces the degradation of the ionomer membrane during the operation of the fuel cell as CeO2 by destruction of reactive oxygen species (e.g.: hydroxyl radical and hydroperoxyl radical) as explained on 11549-11550. It would be obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the catalyst system of Lewinski et al. with the Pt nanoparticles on ceria dispersed into an ionomer matrix as described by Trogadas et al. with the reasonable expectation forming an exchange membrane with improved efficiency, better ionic conductivity, and enhanced durability.
Pertaining to amended Claim 1, the combination of Lewinski et al. and Trogadas et al. discloses a nanoparticulate Pt catalyst which is analogous to the new limitation of Pt black since both materials are elemental Pt and have a small particle size. Since the limitation of amended Claim 1 uses comprising language, the incorporation of a support (e.g.: cerium oxide) for the Pt catalyst (as taught by the combination of Lewinski et al. and Trogadas et al.) is not excluded by the amendment.
Claim 1 was further amended to include two new limitations relating to laminating the anode and the cathode onto the bilayer membrane (i.e.: first and second layers within the membrane) listed below:
Laminating the first layer membrane to the second layer membrane to form a laminated bi-layer membrane having an interface between the first layer membrane and the second layer membrane and operable to allow the passage of cations as indicated in Ex. 7 of Lewinski et al. (¶132-133) where the catalyst containing layer is cast into a film and dried. In Lewinski et al., the catalyst-containing cast film (i.e.: the second layer membrane) is then laminated to the non-catalyst containing layer (i.e.: the first layer membrane) as required by the amendment to Claim 1. Additionally, the binder material used in both layer is Nafion, which is a polymeric perfluorosulfonate material that facilitates the passage of cations such as protons (i.e.: H+ cations).
Dry laminating the anode electrode and the cathode electrode on opposites sides of the laminated bi-layer such that the second layer membrane is closest to the anode as explained in ¶104 describing the formation of the catalyst coated membrane in Lewinski et al.
Lastly, Claim 1 was amended to include the limitation: wherein the bi-layer exchange membrane is operable in a membrane electrode assembly (MEA) upon application of an electrical supply to an anode electrode (¶104) and a cathode electrode (¶104) to conduct protons (i.e.: since the binder for the membrane is Nafion) through the exchange membrane to electrolyze and spilt water into oxygen and hydrogen as indicated in the abstract of Lewinski et al., the background discussion of Lewinski et al. (¶2-4), Claim 1 of Lewinski et al. and the discussion of the construction of a water electrolyzer (cell) in the examples of Lewinski et al.
Regarding Claim 2, Lewinski et al. in view of Trogadas et al. discloses the method per Claim 1 wherein providing the first layer membrane (i.e.: element 222) comprises providing the first layer membrane (i.e.: elements 222) without a catalyst as depicted in LEWINSKI-FIG. 2B by the lack of the recombination Pt-catalyst and for Ex. 7 in Table 3 (¶133). Lewinski et al. further discloses the “Layer 2” membrane composition as being free of platinum in ¶118 for a 50-micrometer thick polymeric perfluorosulfonic acid proton exchange membrane and in ¶133 for a 100-micrometer thick polymeric perfluorosulfonic acid proton exchange membrane in Ex. 7.
Regarding Claim 3, Lewinski et al. in view of Trogadas et al. discloses the method per Claim 1 wherein the exchange membrane comprises a bi-layer exchange membrane (structure 220) as depicted in LEWINSKI-FIG. 2B and described for Ex. 7 in Table 3 (¶133) is disposed between the anode electrode and the cathode electrode.
Regarding Claim 4, Lewinski et al. in view of Trogadas et al. discloses the method as per Claim 1 wherein the anode is disposed directly against the second layer membrane as described in ¶131 where it says “the layer containing platinum was laminated to the iridium anode catalyst (electrode).” The procedure for Ex. 6 was also applied for Ex. 7, so the anode electrode is directly adjacent to the Pt-containing second layer membrane in Ex. 7 as a well (¶133).
Regarding Claim 5, Lewinski et al. in view of Trogadas et al. discloses the method as per Claim 1 wherein the forming comprises: first laminating the first layer membrane to the second layer membrane to form the exchange membrane (Ex. 7 in ¶133); and second laminating the anode electrode to the first side of the exchange membrane, and the cathode electrode to the second side of the exchange membrane to form the membrane electrode assembly (MEA) in ¶104 in the description of fabrication of the full CCM.
Regarding Claim 11, Lewinski et al. in view of Trogadas et al. discloses the method of Claim 1 wherein providing the second layer membrane (element 221) comprises casting a catalyst dispersion (blend of polymeric perfluorosulfonic acid ion exchange resin solution Pt-NSTF perylene red whisker fragments (“Pt-PRWF”) ¶133) onto a substrate (e.g.: 2-mil thick polyimide film) in ¶15, ¶113-7, and ¶165 of the specification.
Regarding Claim 12, Lewinski et al. in view of Trogadas et al. discloses the method of Claim 11 wherein the casting comprises a coating weight (“CW”) of 0.005 to 0.375 mg Pt/cm2 which is derived from the Pt or platinum oxide coating densities listed in ¶31 and second layer membrane coating thickness in Table 3 of Lewinski. In the examples in Table 3, the typical thickness of the Pt-containing second layer membrane is ~50 microns (which equals 0.005 cm) and the Pt-coating volume range from 1 mg/cm3 to 75 mg/cm3 (¶31). The upper and lower ranges of the Pt coating weight is calculated from the product of the average layer thickness and the coating density:
UPPER CW RANGE = 0.005 cm x 75 mg/cm3 = 0.375 mg/cm2 Pt
LOWER CW RANGE = 0.005 cm x 1 mg/cm3 = 0.005 mg/cm2 Pt
A prima facie case of obviousness exists when the range taught in the prior art overlaps with the claimed range (i.e.: 0.01 to 0.5 mg Pt/cm2). See MPEP 2144.05(I) - OVERLAPPING, APPROACHING, AND SIMILAR RANGES, AMOUNTS, AND PROPORTIONS
Regarding Claim 17, Lewinski et al. in view Trogadas et al. discloses the method of Clam 1, wherein providing the first layer membrane comprises providing a NAFION membrane (Table 3 - Ex. 7: in ¶133) and the providing the second layer membrane comprises providing an ionomer (Table 3 - Ex. 7: in ¶133) with a platinum-catalyst (Table 3 – Ex. 7 in ¶133).
Regarding Claim 18, Lewinski et al. in view of Trogadas et al. discloses the method of Claim 1 with the Examples in Table 3 having the bilayer construction depicted in LEWINSKI-FIG. 2B (Ex. 6, 7, 15, 17-20, and 23-26 with different recombination catalyst types). In said Examples, the first layer membrane (element 222) ranges in thickness from 2.0 mils (50 microns) to 4.0 mils (100 microns) and the second layer membrane (element 221) ranges in thickness from 1 mil (25 microns) to 2 mils (50 microns) Additionally, Lewinski et al. teaches the total thickness of the exchange membrane (220 = 221 + 222) ranges from less than 2 mils (50 microns) to more than 10 mils (250 microns) in ¶20. A prima facie case of obviousness exists when the range taught in the prior art overlaps with the claimed range. See MPEP 2144.05(I) - OVERLAPPING, APPROACHING, AND SIMILAR RANGES, AMOUNTS, AND PROPORTIONS
Regarding Claim 31, Lewinski et al. in view of Trogadas et al. discloses the method of Claim 1, where the second layer comprises, a radical scavenger by the presence of cerium hydroxide. Trogadas et al. indicated that CeO2 destroys (i.e.: scavenges ) reactive oxygen species (e.g.: hydroxyl radical and hydroperoxyl radical) as explained on 11549-11550 (and exemplified in Fig. 4 where the presence of CeO2 significantly reduces the formation of fluoride).
10. Claim 16 is rejected under 35 U.S.C. 103 as being obvious over Lewinski et al. in view of Trogadas et al. with Leddy et al. used as evidence of inherency.
Lewinski et al. (US Pub. No. 2020/0102660 A1 – previously presented) is directed toward water electrolyzers comprising a recombination layer (Title and Abstract). Trogadas et al. (“Platinum supported on CeO2 effectively scavenges free radicals within the electrolyte of an operating fuel cell,” Chem. Comm. 2011, 47, 11549-11551 – previously presented) is directed at radical scavenging in operating fuel cells (pg. 11549: title). Leddy et al. (“Density and Solubility of Nafion: Recast, Annealed, and Commercial Films” Anal. Chem. 1996, 68, 3793-3796 – previously presented) is teaches general properties of Nafion.
Regarding Claim 16, Lewinski et al. in view of Trogadas et al. with support from Leddy et al. (which lists the density of Nafion as 1.58 g/cm3 on pg. 3783: Introduction) teaches the method per Claim 1 wherein the laminate (exchange membrane 220) is 0.01% to 4.53% catalyst by weight (see TABLE I for calculation using the laminate thickness and coating weights of Pt in the laminate). A prima facie case of obviousness exists when the claimed range overlaps with the range disclosed in the prior art. See MPEP 2144.05(I) - OVERLAPPING, APPROACHING, AND SIMILAR RANGES, AMOUNTS, AND PROPORTIONS.
TABLE I. Catalyst Loading Calculation.
Total laminate thickness ranges from 50 micron to 250 microns (Lewinski et al. ¶20)
Density of Nafion is 1.58 g/cm3 which comprises the laminate (Leddy et al. pg. 3783: Introduction)
Lower coating weight of Nafion in Laminate = 1580 mg/cm3 x 0.005 cm = 7.9 mg/cm2
Upper coating weight of Nafion in Laminate = 1580 mg/cm3 x 0.0250 cm = 39.5 mg/cm2
Recombination Catalyst Loading Range in Laminate = 0.005 mg Pt/cm2 to 0.375 mg Pt/cm2 (see above for calculation in Claim 12).
Upper bound catalyst wt.% = (0.375 mg Pt/cm2)/(7.9 mg/cm2 Nafion + 0.375 mg/cm2) = 4.53 wt.%
Lower bound catalyst wt.% = (0.005 mg Pt/cm2)/(39.5 mg/cm2 Nafion + 0.005 mg/cm2) = 0.01 wt.%
Catalyst Weight % in the Laminate: 0.01 to 4.53 wt. %
11. Claims 6 is rejected under 35 U.S.C. 103 as being unpatentable over Lewinski et al. and Trogadas et al. as applied to Claim 1 above and in view of Stähler et al. and in further view of Park et al.
Lewinski et al. (US Pub. No. 2020/0102660 A1 – previously presented) is directed toward water electrolyzers comprising a recombination layer (Title and Abstract). Trogadas et al. (“Platinum supported on CeO2 effectively scavenges free radicals within the electrolyte of an operating fuel cell,” Chem. Comm. 2011, 47, 11549-11551 – previously presented) is directed at radical scavenging in operating fuel cells (pg. 11549: title). Stähler et al. (“A completely slot die coated membrane electrode assembly,” Int. J. Hydrogen Energy 2019, 44, 7053-7058 – previously presented) is directed toward slot die coating (pg. 7053: title). Park et al. (“Roll-to-roll production of catalyst coated membranes for low-temperature electrolyzers,” J. Power Sources 2020, article 228819, pages 1-9 – previously presented) is directed toward roll-to-roll production of electrolyzers (pg. 1: title).
Regarding Claim 6, Lewinski et al. in view of Trogadas et al. discloses the method per Claim 1 wherein the providing and depositing of the second layer membrane slurry occurs using a microfilm applicator on a Kapton substrate (¶133). Lewinski et al. in view of Trogadas et al. does not disclose deposition of the slurry onto a moving substrate via a roll-to-roll process, but rather application for a small-scale operation (Lewinski et al. ¶119-121).
The use of a roll-to-roll operation to produce materials and electrodes in high volume/throughput and high quality for energy storage applications is well known (Park et al. pg. 2: Introduction). Often these processes utilize slot die coating (SDC) or gravure coatings to apply a slurry to a substrate (Park et al. pg. 2: Introduction). For example, Stähler et al. discloses a SDC operation to apply an ionomer or ionomer/catalyst slurry (pg. 7053: title and abstract) onto either a moving PTFE substrate (or another deposited layer) as shown in Fig. 1 on page 7055. The ionomer only slurry in Stähler et al. would provide the first layer membrane (no catalyst) and the ionomer/catalyst slurry of Stähler et al. would provide the second layer membrane according to the instant application. An example of a slot die coating process for the continuous production (i.e.: roll-to-roll) for depositing a catalyst slurry for use in membrane electrode assemblies is disclosed in Park et al. (pg.: 1 Abstract and Title). Park et al. teaches the direct deposition of catalyst/Nafion slurry deposited onto a substrate (i.e.: membrane) (PARK-FIG. 1).
Since the second layer membrane slurry composition disclosed in Lewinski et al. comprises a mixture of Pt/ionomer like the slurries deposited using slot die coating in both Stähler et al. and Park et al., one ordinary skill in the art would reasonably expect to be able to modify some of the characteristics of the ink of Lewinski (e.g.: viscosity, polymer wetting, polymer swelling, etc.) using the specific teachings in Park et al. to adapt the catalyst/ionomer for a slot die coating deposition process as part of a normal optimization procedures (see MPEP 2144.05 II). Therefore, it would be obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to modify the deposition method and slurry of Lewinski to enable using a continuous process (i.e.: roll-to-roll) to deposit the slurry onto a moving substrate by slot die coating as taught by the combination of Stähler et al. and Park et al. The resultant second layer membrane would be expected to be equivalent to the membrane layer made by other small-scale production processes (Park et al. pg. 7-8: 4. Conclusion).
12. Claim 7 is rejected under 35 U.S.C. 103 as being unpatentable over Lewinski et al. and Trogadas et al. as applied to Claim 5 above, and in further view of Stähler et al., Park et al., and Chen et al.
Lewinski et al. (US Pub. No. 2020/0102660 A1 – previously presented) is directed toward water electrolyzers comprising a recombination layer (Title and Abstract). Trogadas et al. (“Platinum supported on CeO2 effectively scavenges free radicals within the electrolyte of an operating fuel cell,” Chem. Comm. 2011, 47, 11549-11551 – previously presented) is directed at radical scavenging in operating fuel cells (pg. 11549: title). Stähler et al. (“A completely slot die coated membrane electrode assembly,” Int. J. Hydrogen Energy 2019, 44, 7053-7058 – previously presented) is directed toward slot die coating (pg. 7053: title). Park et al. (“Roll-to-roll production of catalyst coated membranes for low-temperature electrolyzers,” J. Power Sources 2020, article 228819, pages 1-9 – previously presented) is directed toward roll-to-roll production of electrolyzers (pg. 1: title). Chen et al. (“High-rate roll-to-roll stack and lamination of multilayer structured membrane electrode assembly,” J. Manuf. Process. 2016, 23, 175-182 – previously presented) is directed toward roll-to-roll stack and lamination procedures (pg. 175: title).
Regarding Claim 7, Lewinski et al. and Trogadas et al. disclose the method of Claim 5; however, said references do not disclose deposition of the slurry onto a moving substrate via a roll-to-roll process, but rather application for a small-scale operation (Lewinski et al. ¶119-121).
The use of a roll-to-roll operation to produce materials and electrodes in high volume/throughput and high quality for energy storage applications is well known (Park et al. pg. 2: Introduction). Often these processes utilize slot die coating (SDC) or gravure coatings to apply a slurry to a substrate (Park et al. pg. 2: Introduction). For example, Stähler et al. discloses a SDC operation to apply an ionomer or ionomer/catalyst slurry (pg. 7053: title and abstract) onto either a moving PTFE substrate (or another deposited layer) as shown in Fig. 1 on page 7055. The ionomer only slurry in Stähler et al. would provide the first layer membrane (no catalyst) and the ionomer/catalyst slurry of Stähler et al. would provide the second layer membrane according to the instant application. An example of a slot die coating process for the continuous production (i.e.: roll-to-roll) for depositing a catalyst slurry for use in membrane electrode assemblies is disclosed in Park et al. (pg.: 1 Abstract and Title). Park et al. teaches the direct deposition of catalyst/Nafion slurry deposited onto a substrate (i.e.: membrane) (PARK-FIG. 1).
Since the second layer membrane slurry composition disclosed in Lewinski et al. and Trogadas et al. comprises a mixture of Pt/ionomer like the slurries deposited using slot die coating in both Stähler et al. and Park et al., one ordinary skill in the art would reasonably expect to be able to modify some of the characteristics of the ink of Lewinski (e.g.: viscosity, polymer wetting, polymer swelling, etc.) using the specific teachings in Park et al. to adapt the catalyst/ionomer for a slot die coating deposition process as part of a normal optimization procedures (see MPEP 2144.05 II). Therefore, it would be obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to modify the deposition method and slurry of Lewinski to enable using a continuous process (i.e.: roll-to-roll) to deposit the slurry onto a moving substrate by slot die coating as taught by the combination of Stähler et al. and Park et al. The resultant second layer membrane would be expected to be equivalent to the membrane layer made by other small-scale production processes (Park et al. pg. 7-8: 4. Conclusion).
Chen et al. is directed toward a high-rate roll-to-roll process for stacking and laminating multilayer membrane electrode assemblies (pg. 175: Title). CHEN-FIG. 3 below depicts multiple unwinding processes, stacking process, and lamination process that Chen et al. discloses to form a multilayer membrane electrode assembly. Adapting this process to the first layer membrane, second layer membrane, anode catalyst layer, and cathode catalyst layer that have been deposited onto temporary substrates would be obvious to one of ordinary skill in the art given the teachings of Lewinski et al., Stähler et al., and Park et al. First, Lewinski et al. and Trogadas et al. disclose the method of laminating a stack of materials (¶133), while Stähler et al. discloses the deposition of ionomer or catalyst/ionomer slurry onto a moving substrate, and Park et al. discloses the deposition of a slurry using a roll-to-roll process. Combination of the teachings of Lewinski et al., Trogadas et al, Stähler et al., and Park et al. would allow for the production of separate rolls of material of the first layer membrane, the second layer membrane, the anode catalyst layer, and the cathode catalyst that can be laminated into a single membrane electrode assembly. Before the effective filing date of the claimed invention, it would be obvious to one of ordinary skill in the art to stack and laminate the MEA layers from Lewinski et al, Stähler et al, and Park et al. with the apparatus disclosed by Chen et al. with the reasonable expectation of fabricating a membrane electrode assembly in a continuous process without the need for manual preparation (Chen et al. pg. 181: Conclusion).
13. Claims 8, 9, and 10 are rejected under 35 U.S.C. 103 as being unpatentable over Lewinski et al. in view of Trogadas et al. as applied to Claim 1 above, and in further view of the combination Stähler et al., Park et al. and Chen et al.
Lewinski et al. (US Pub. No. 2020/0102660 A1 – previously presented) is directed toward water electrolyzers comprising a recombination layer (Title and Abstract). Trogadas et al. (“Platinum supported on CeO2 effectively scavenges free radicals within the electrolyte of an operating fuel cell,” Chem. Comm. 2011, 47, 11549-11551 – previously presented) is directed at radical scavenging in operating fuel cells (pg. 11549: title). Stähler et al. (“A completely slot die coated membrane electrode assembly,” Int. J. Hydrogen Energy 2019, 44, 7053-7058 – previously presented) is directed toward slot die coating (pg. 7053: title). Park et al. (“Roll-to-roll production of catalyst coated membranes for low-temperature electrolyzers,” J. Power Sources 2020, article 228819, pages 1-9 – previously presented) is directed toward roll-to-roll production of electrolyzers (pg. 1: title). Chen et al. (“High-rate roll-to-roll stack and lamination of multilayer structured membrane electrode assembly,” J. Manuf. Process. 2016, 23, 175-182 – previously presented) is directed toward roll-to-roll stacking and lamination processes for MEAs (pg. 175: title).
Regarding Claim 8, Lewinski et al. in view of Trogadas et al. discloses a method of providing a layup to form a membrane electrode assembly, but the process is not continuous. The method of Lewinski et al. also forms the bilayer exchange membrane (structure 220) followed by laminating the anode and cathode catalyst layers to the exchange membrane (¶133). Lewinski et al. does not disclose a layup of the cathode layer, the first layer membrane, the second layer membrane, and the anode catalyst layer with an interface between the first and second layer membranes. The preceding layup can be derived by one of ordinary skill in the art by the combination of Lewinski et al., Trogadas et al., Stähler et al., Park et al. and Chen et al. as discussed below.
The use of a roll-to-roll operation to produce materials and electrodes in high volume/throughput and high quality for energy storage applications is well known (Park et al. pg. 2: Introduction) using SDC to apply a slurry to a substrate (Park et al. pg. 2: Introduction). As discussed above, Stähler et al. discloses a SDC operation to apply an ionomer or ionomer/catalyst slurry (pg. 7053: title and abstract) onto a moving PTFE substrate (or another deposited layer) as shown in Fig. 1 on page 7055. This coating can be extended to a roll-to-roll process as disclosed in Park et al. by application of the apparatus in PARK-FIG. 1.
Chen et al. is directed toward a high-rate roll-to-roll process for stacking and laminating multilayer membrane electrode assemblies (pg. 175: Title). CHEN-FIG. 3 above depicts multiple unwinding processes, stacking process, and lamination process that Chen et al. discloses to form a multilayer membrane electrode assembly. Adapting this process to the first layer membrane, second layer membrane, anode catalyst layer, and cathode catalyst layer that have been deposited onto temporary substrates using a continuous process would be obvious to one of ordinary skill in the art given the teachings of Lewinski et al., Stähler et al., and Park et al. The separate rolls of material can be unrolled and stacked into the layup described in Claim 8 of the present application followed by lamination to form the membrane electrode assembly. Before the effective filing date of the claimed invention, it would be obvious to one of ordinary skill in the art to stack (i.e.: provide a layup) and laminate the MEA layers from Lewinski et al, Stähler et al, and Park et al. with the apparatus disclosed by Chen et al. with the reasonable expectation of fabricating a membrane electrode assembly in a continuous process without the need for manual preparation (Chen et al. pg. 181: Conclusion).
Regarding Claim 9, Lewinski et al. and Trogadas et al. in view of the combination of Stähler et al., Park et al. and Chen et al. discloses the method of Claim 8 wherein the providing the layup comprises a roll-to-roll process of providing the second layer membrane comprising depositing a slurry on a moving substrate. Specifically, the second layer membrane slurry composition disclosed in Lewinski et al. and Trogadas et al. comprises a mixture of Pt/ionomer/CeO2 like the slurries deposited using slot die coating in both Stähler et al. and Park et al. Modifying some of the characteristics of the ink of Lewinski/Trogadas (e.g.: viscosity, concentrations, solvent, polymer wetting, polymer swelling, etc.) using the specific teachings in Park et al. to adapt the catalyst/ionomer for a slot die coating deposition process as part of a normal optimization procedure would allow the deposition of the slurry onto a moving substrate as claimed in Claim 9.
Regarding Claim 10, Lewinski et al. and Trogadas et al. in view of the combination of Stähler et al., Park et al. and Chen et al. discloses the method of Claims 8 and 9 wherein: the laminating process comprises a single roll-to-roll laminating process of the layup. Specifically, combination of the teachings of Lewinski et al., Trogadas et al., Stähler et al., and Park et al. would allow for the production of separate rolls of material of the first layer membrane, the second layer membrane, the anode catalyst layer, and the cathode catalyst of the present application as described in Claim 8. These layers could be combined into a layup that is laminated in a single roll-to-roll process using the apparatus of Chen et al. depicted in CHEN-FIG. 3 above.
14. Claim 13 is rejected under 35 U.S.C. 103 as being unpatentable over Lewinski et al. and Trogadas et al. as applied to Claim 11 above, and further in view of Klose et al.
Lewinski et al. (US Pub. No. 2020/0102660 A1 – previously presented) is directed toward water electrolyzers comprising a recombination layer (Title and Abstract). Trogadas et al. (“Platinum supported on CeO2 effectively scavenges free radicals within the electrolyte of an operating fuel cell,” Chem. Comm. 2011, 47, 11549-11551 – previously presented) is directed at radical scavenging in operating fuel cells (pg. 11549: title). Klose et al. (“Membrane Interlayer with Pt Recombination Particles for Reduction of the Anodic Hydrogen Content in PEM Water Electrolysis”, J. Electrochem. Soc. 2018, 165, F1271-F1277 – previously presented) is directed toward a Pt-recombination interlayer (pg. F1271: title).
Regarding Claim 13, Lewinski et al. discloses a method per Claim 11 wherein: the providing the second layer membrane (element 221 in LEWINSKI-FIG. 2B) comprises providing the catalyst dispersion (blend of polymeric perfluorosulfonic acid ion exchange resin and Pt-catalyst in ¶133) to form the layer on the substrate. However, Lewinski et al. does not disclose the formation of the second layer membrane containing the recombination catalyst to be formed using multiple coating passes nor achieving the predetermined thickness using successive coatings.
Klose et al. is directed toward a membrane interlayer with Pt recombination particles (pg. F1271: title and abstract). Klose et al. disclose an exchange membrane with a similar structure to Lewinski as depicted in KLOSE-FIG. 2 comprised of a 1st layer (analogous to the first layer membrane of the instant application), a 2nd layer (analogous to the second layer membrane of the instant application), and an interface between said membrane layers. The 2nd Layer contains a platinum catalyst formed by the application of a dispersion (comprised of a platinum catalyst and perfluorosulfonic acid ionomer) in successive layers to apply a total thickness of ~1 mil (26 microns) as depicted in the schematic Figure 1 of Klose et al. (pg. F1272) and described in the membrane electrode assembly section of the materials and methods (pg. F1272). The application procedure of Klose et al. results in a very consistent layer thickness as evidenced by the tolerance of 1 micron, resulting in a ~4% variation across the entire second layer membrane (pg. F1272). The dispersion composition of Klose et al. is also similar to the dispersion composition described in Lewinski et al. used to form the second layer membrane (i.e.: fluorinated ionomer and Pt-catalyst). It would be obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the application method disclosed in Lewinski et al. which casts the second layer membrane in a single operation with the layer-by-layer application approach of Klose et al. with the reasonable expectation of having greater control over the thickness of the second layer membrane. The greater control as per the method of Klose et al. would result in an exchange membrane that has improved safety (no H2 formation in the O2), and low membrane degradation over long cycling periods (pg. F1275: conclusion).
15. Claims 14 is rejected under 35 U.S.C. 103 as being unpatentable over Lewinski et al. and Trogadas et al. as applied to Claim 11 above, and further in view of Endo et al.
Lewinski et al. (US Pub. No. 2020/0102660 A1 – previously presented) is directed toward water electrolyzers comprising a recombination layer (Title and Abstract). Trogadas et al. (“Platinum supported on CeO2 effectively scavenges free radicals within the electrolyte of an operating fuel cell,” Chem. Comm. 2011, 47, 11549-11551 – previously presented) is directed at radical scavenging in operating fuel cells (pg. 11549: title). Endo et al. (JP2006107914A – EPO translation; previously presented) is directed toward an electrolyte film for a solid polymer electrolyte having a sparingly soluble cerium compound (abstract).
Regarding Claim 14, Lewinski et al. and Trogadas et al. disclose the dispersion composition comprising a fluorinated ionomer (e.g.: Nafion ¶133) and a platinum-based recombination catalyst (e.g.: metallic platinum in the abstract and ¶133). However, Lewinski et al. and Trogadas et al. does not disclose the use cerium hydroxide in the second layer membrane.
Endo et al. discloses the inclusion of sparingly soluble cerium compound to suppress the radical promoted degradation of the polymer electrolyte membrane as is typical known for fluoropolymers (¶11). The sparingly soluble cerium compound is incorporated into the polymer dispersion using an ultrasonic homogenizer and then cast to make a membrane (¶13-14, ¶55, and ¶57). This membrane composition is resistant to peroxide or radical degradation (¶17) and the poorly soluble compound furnishes low levels of soluble Ce ions which shuttle between the III and IV oxidation states in reacting with peroxides and radicals (¶18). The low solubility of the cerium compound, including cerium hydroxide (¶29), prevent significant migration of the cerium ions outside of the membrane (¶17). Endo et al. further discloses it is advantageous to have the cerium compounds present in the membrane layer(s) closest to the anode (such as the second layer membrane) as per ¶20.
It would be obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to modify the second layer membrane (dispersion) composition of Lewinski et al. and Trogadas et al. with poorly soluble cerium hydroxide as discussed in Endo et al. with the reasonable expectation of providing an exchange membrane that has a second layer membrane that is very resistant to peroxide or radical decomposition because significant levels of Ce will not leach out of said layer (Endo et al. ¶17).
16. Claims 15 is rejected under 35 U.S.C. 103 as being unpatentable over Lewinski et al. and Trogadas et al. as applied to Claim 11 above, and further in view of Endo et al. and Du et al.
Lewinski et al. (US Pub. No. 2020/0102660 A1 – previously presented) is directed toward water electrolyzers comprising a recombination layer (Title and Abstract). Trogadas et al. (“Platinum supported on CeO2 effectively scavenges free radicals within the electrolyte of an operating fuel cell,” Chem. Comm. 2011, 47, 11549-11551 – previously presented) is directed at radical scavenging in operating fuel cells (pg. 11549: title). Endo et al. (JP2006107914A – EPO translation, previously presented) is directed toward an electrolyte film for a solid polymer electrolyte having a sparingly soluble cerium compound (abstract). Du et al. (“Effects of ionomer and dispersion methods on the rheological behavior of proton exchange membrane fuel cell catalyst ink,” Int. J. Hydrogen Energy 2020, 45(53), 29430-29441 – previously presented) is directed toward dispersion methods for proton exchange membranes (pg. 29430: title). Nafion Product Bulletin P-14 (Chemours, Year: 2020 – previously presented) provides physical properties of Nafion ionomer dispersions (previously presented).
Claim 15 of the present application claims the following weight ratios: 160 mg Pt black, 10.1 mg cerium hydroxide, and 80 g ionomer (e.g.: Nafion 2020/1 dispersion) in the second layer membrane dispersion. The Nafion Product Bulletin P-14 indicates the % polymer in Nafion D2020/1 is 20%, so 80 g of Nafion 2020/1 dispersion is a mixture of 16 g of ionomer and the remainder is a blend of water and alcohol solvent (in the “typical composition” table). The present application identifies cerium hydroxide as a radical scavenger, but does not disclose a specific range for the material (see ¶41, 46, 52, and 55 referenced as US Pub. No. 20220243339A1), but only the value listed above. When the weights of Claim 15 of the instant application are normalized to 100% and converted to the composition of the deposited second layer membrane (i.e.: sans solvent), the following results: ~1.0% platinum black, ~0.1% cerium hydroxide, and ~99% Nafion (2020) ionomer.
Regarding Claim 15, Lewinski et al. in view of Trogadas et al. discloses the dispersion composition comprising a platinum-based recombination catalyst (up to 4.53 wt. % as per TABLE 1) and the remainder of the composition is a Nafion-ionomer (at least 95.5 wt.%) as discussed in Claim 11 above. However, Lewinski et al. in view of Trogadas et al. does not disclose the use of cerium hydroxide as a radical scavenger in the second layer membrane nor the second layer membrane slurry.
Endo et al. discloses the inclusion of sparingly soluble cerium compound to suppress the radical promoted degradation of the polymer electrolyte membrane as is typical for fluoropolymers (¶11). The sparingly soluble cerium compound (such as cerium hydroxide in ¶29) is incorporated into the Pt/polymer dispersion by ultrasonic homogenizer and then cast to make a membrane (¶13-14, ¶55, and ¶57). This membrane composition is resistant to peroxide or radical degradation (¶17) because of the low levels of soluble Ce ions (¶18), which does not significantly migrate outside of the second layer membrane (¶17). Endo et al. further discloses it is advantageous to have the cerium compounds present in the membrane layer(s) closest to the anode (such as the second layer membrane) as per ¶20.
Endo et al. discloses the range of 0.3% by weight to 80% by weight for the content of the sparingly soluble cerium complex in the exchange membrane (¶22-23), but concedes the level of cerium hydroxide must be selected to effectively balance efficient peroxide destruction and sufficient electrical conductivity in the membrane. Therefore, the cerium hydroxide concentration is a result-effective variable, i.e., a variable which achieves a recognized result, and the determination of the optimum or workable ranges of said variable might be characterized as routine experimentation (See MPEP 2144.0.II.B.). Accordingly, it would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to have discovered the optimum or workable ranges of the cerium hydroxide concentration, including values within the claimed range, through routine experimentation. One would have been motivated to do so in order to have formed a membrane layer (upon slurry deposition) with enough cerium hydroxide to scavenge peroxides radicals while still maintaining appropriate electrical conductivity.
In ¶29, Endo et al. discloses effective dispersion of sparingly soluble cerium hydroxide, Pt-catalyst, and Nation ionomer using an ultrasonic homogenizer (¶55 and ¶57), but does not teach ball milling as an alternative dispersion method for the slurry. Du et al. is a study directed at understanding the impact of dispersion method on catalyst slurries properties (pg. 29430: title and abstract). Specifically, Du et al. compares ball milling (at different times) and sonicating (i.e.: ultrasonic homogenizer at difference intensities) as depicted in flowchart in Figure 3 after the initial mixing (pg. 29434). From the results of the study, Du et al. indicated that the ball milled material had a more responsive thixotropic recovery which is beneficial for effective ink application (pg. 29439: Conclusion). Moreover, Du et al. indicated that ball milling the ink resulted in a higher zeta potential than ultrasonic homogenization meaning the ink is more stable when the final dispersion is ball milling (pg. 29439: Conclusion). Therefore, it would be obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to prepare the dispersion of Lewinski et al. and Endo et al. using ball milling as dispersion method of Du et al. with the reasonable expectation of making a catalyst slurry is robust application and storage properties.
17. Claims 23, 24, 25, 30, and 32 are rejected under 35 U.S.C. 103 as being obvious over Lewinski et al. in view of Trogadas et al. and Du et al.
Lewinski et al. (US Pub. No. 2020/0102660 A1 – previously presented) is directed toward water electrolyzers comprising a recombination layer (Title and Abstract). Trogadas et al. (“Platinum supported on CeO2 effectively scavenges free radicals within the electrolyte of an operating fuel cell,” Chem. Comm. 2011, 47, 11549-11551 – previously presented) is directed at radical scavenging in operating fuel cells (pg. 11549: title). Du et al. (“Effects of ionomer and dispersion methods on the rheological behavior of proton exchange membrane fuel cell catalyst ink,” Int. J. Hydrogen Energy 2020, 45(53), 29430-29441 – previously presented) is directed toward dispersion methods for proton exchange membranes (pg. 29430: title).
Regarding Claim 23, Lewinski et al. in view of discloses a method comprising: providing a first layer membrane (element 222 in LEWINSKI-FIG. 2B) having a first thickness (Table 3: Ex. 7 - Layer 2 with 100-micron thickness); providing a second layer membrane (element 221 in LEWINSKI-FIG. 2B) having a thickness less than the first thickness (Table 3: Ex. 7 - Layer 1 with 25-micron dried film thickness). Lewinski et al. further teaches that the second layer membrane comprises a platinum catalyst (e.g.: Pt/Pt oxide nanostructured thin film catalyst supported on perylene whiskers in Table 1 and Table 3: Ex. 7) and the first layer membrane does not contain any catalyst (Table 3: Ex. 7). Lewinski et al. further discloses the “Layer 2” membrane composition as being free of platinum in ¶118 for a 50-micrometer thick polymeric perfluorosulfonic acid proton exchange membrane and in ¶133 for a 100-micrometer thick polymeric perfluorosulfonic acid proton exchange membrane in Ex. 7. Lewinski et al. also an exchange membrane having an interface between the first membrane layer and the second membrane layer in the lamination procedure in Ex. 7 (¶133 and LEWINSKI-FIG. 2B).
Lewinski et al. discloses the catalyst layer comprising Pt/Pt oxide nanostructured thin film catalyst supported on perylene whiskers, but does not explicitly disclose nanoparticle catalyst dispersed throughout the ionomer layer. Lewinski et al. indicates that water electrolyzers membrane electrode assemblies that are similar to the proton exchange membranes used in fuel cells (¶2) meaning that one of ordinary skill in the art would be motivated to investigate fuel cell membranes for teachings relevant to the water electrolyzers.
Trogadas et al. teaches the addition of nanoparticulate platinum supported on CeO2 dispersed throughout the thickness of the ionomer layer (e.g.: Nafion) (pg. 11550: last paragraph left side and TEM image in Fig. 2). Trogadas et al. further indicates that the ionic conductivity significantly increases when the composite layer is 2 wt.% Pt on cerium oxide in a Nafion layer (pg. 11550: Fig. 3) meaning the electrochemical cell will be more efficient. Moreover, Trogadas et al. indicates evaluated the electrochemical performance of fuel cells that had low H2 crossover (ESI pg. 2-3: MEA testing - Performance and durability), which was also a focused of Lewinski et al. (reducing hydrogen crossover which lowers efficiency). The composite electrode with 2% Pt and CeO2 had the best electrochemical performance (pg. 11551: Fig. 5). Another potential benefit of the presence of CeO2 also reduces the degradation of the ionomer membrane during the operation of the fuel cell as CeO2 by destruction of reactive oxygen species (e.g.: hydroxyl radical and hydroperoxyl radical) as explained on 11549-11550. It would be obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the method of Lewinski et al. with the Pt nanoparticles on ceria dispersed into an ionomer matrix as described by Trogadas et al. with the reasonable expectation forming an exchange membrane with improved efficiency, better ionic conductivity, and enhanced durability.
Pertaining to amended Claim 23, Lewinski et al. in view of Trogadas et al. discloses the preparation a cerium oxide supported platinum nanoparticle (analogous to Pt black) via a chemical reaction to form the oxide of cerium and metallic Pt from soluble metal ions (Trogadas et al. pg. 11549-pg. 11550). The metal oxide-supported Pt was then combined with Nafion to form the slurry, cast onto glass plates to form the membrane layer (Trogadas et al. pg. 11550), but does not specify the method of mixing to form the slurry. Ball milling is a very common technique used to form well dispersed slurries with small, uniform particle sized for use of said slurries in electrolyzer and water splitting application. Du et al. is a study directed at understanding the impact of dispersion method on catalyst slurries properties (pg. 29430: title and abstract). Specifically, Du et al. compares ball milling (at different times) and sonicating (i.e.: ultrasonic homogenizer at difference intensities) as depicted in flowchart in Figure 3 after the initial mixing (pg. 29434). From the results of the study, Du et al. indicated that the ball milled material had a more responsive thixotropic recovery which is beneficial for effective ink application (pg. 29439: Conclusion). Moreover, Du et al. indicated that ball milling the ink resulted in a higher zeta potential than ultrasonic homogenization meaning the ink is more stable when the final dispersion is ball milling (pg. 29439: Conclusion). Therefore, it would be obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to prepare the dispersion of Lewinski et al. and Trogadas et al. using ball milling as dispersion method of Du et al. with the reasonable expectation of making a catalyst slurry is robust application and storage properties.
Regarding the further amendments to Claim 23, the new steps for the order of laminating layers in Claim 23 are obvious in light of the lamination process for forming the CCM of Ex. 7 of Lewinski et al. (¶132-33). According to MPEP 2144.04(IV): Rationale C - CHANGES IN THE SEQUENCE OF ADDING INGREDIENTS, a prima facie case of obviousness exists regarding the selection in the order of performing process steps (i.e.: the order of laminating each layer to each other to form the CCM).
Regarding Claim 24, Lewinski et al. in view of Trogadas et al. and Du et al. discloses the method per Claim 23 wherein: providing the first layer membrane (element 222) comprises providing the first layer membrane (element 222) without a catalyst (Table 3 – Example 7) as depicted in LEWINSKI-FIG. 2B by the lack of the recombinant catalyst in element 222; and the exchange membrane comprises a bi-layer exchange membrane (structure 220) as depicted in LEWINSKI-FIG. 2B. Lewinski et al. further discloses the “Layer 2” membrane composition as being free of platinum in ¶118 for a 50-micrometer thick polymeric perfluorosulfonic acid proton exchange membrane and in ¶133 for a 100-micrometer thick polymeric perfluorosulfonic acid proton exchange membrane in Ex. 7.
Regarding Claim 25, Lewinski et al. in view of Trogadas et al. and Du et al. discloses the method of Claim 23 wherein the forming of the exchange membrane comprises: hot pressing using a laminator (set to 350℉, 150 psi, and a roller speed of 0.5 ft/minute in ¶122) the first layer membrane (element 222) to the second layer membrane (element 221) to form the exchange membrane (structure 220) depicted in LEWINSKI-FIG. 2B as described in ¶133 where is says the platinum-containing membrane (element 221) was laminated to a 100-micrometer thick perfluorosulfonic acid proton exchange membrane (element 222) resulting in a total thickness of 125 micrometers.
Regarding Claim 30, Lewinski et al. in view of Trogadas et al. and Du et al. discloses the method of Claim 23 with the Examples in Table 3 having the bilayer construction depicted in LEWINSKI-FIG. 2B (Ex. 6, 7, 15, 17-20, and 23-26 with different recombination catalysts). In said Examples, the first layer membrane (element 222) ranges in thickness from 2.0 mils (50 microns) to 4.0 mils (100 microns) and the second layer membrane (element 221) ranges in thickness from 1 mil (25 microns) to 2 mils (50 microns). Additionally, Lewinski et al teaches the total thickness of the exchange membrane ranges ((220 = 221 + 222) from less than 2 mils (50 microns) to more than 10 mils (250 microns) in ¶20. A prima facie case of obviousness exists when the range taught in the prior art overlaps with the claimed range. See MPEP 2144.05(I) - OVERLAPPING, APPROACHING, AND SIMILAR RANGES, AMOUNTS, AND PROPORTIONS.
Regarding Claim 32, Lewinski et al. in view of Trogadas et al. and Du et al. discloses the method of Claim 23, where the second layer comprises, a radical scavenger by the presence of cerium hydroxide. Trogadas et al. indicated that CeO2 destroys (i.e.: scavenges ) reactive oxygen species (e.g.: hydroxyl radical and hydroperoxyl radical) as explained on 11549-11550 (and exemplified in Fig. 4 where the presence of CeO2 significantly reduces the formation of fluoride).
18. Claim 29 is rejected under 35 U.S.C. 103 as being obvious over Lewinski et al. in view of Trogadas et al. and Du et al. with Leddy et al. used as evidence of inherency.
Lewinski et al. (US Pub. No. 2020/0102660 A1 – previously presented) is directed toward water electrolyzers comprising a recombination layer (Title and Abstract). Trogadas et al. (“Platinum supported on CeO2 effectively scavenges free radicals within the electrolyte of an operating fuel cell,” Chem. Comm. 2011, 47, 11549-11551) is directed at radical scavenging in operating fuel cells (pg. 11549: title). Du et al. (“Effects of ionomer and dispersion methods on the rheological behavior of proton exchange membrane fuel cell catalyst ink,” Int. J. Hydrogen Energy 2020, 45(53), 29430-29441 – previously presented) is directed toward dispersion methods for proton exchange membranes (pg. 29430: title). Leddy et al. (“Density and Solubility of Nafion: Recast, Annealed, and Commercial Films” Anal. Chem. 1996, 68, 3793-3796 – previously presented) is teaches general properties of Nafion.
Regarding Claim 29, Lewinski et al. in view of Trogadas et al. and Du et al. with evidentiary support from Leddy et al. (which lists the density of Nafion as 1.58 g/cm3 on pg. 3783: Introduction) teaches the method per Claim 1 wherein the laminate (exchange membrane 220) is 0.01% to 4.53% catalyst by weight (see TABLE II for calculation using the laminate thickness and coating weights of Pt in the laminate). A prima facie case of obviousness exists when the claimed range overlaps with the range disclosed in the prior art. See MPEP 2144.05(I) - OVERLAPPING, APPROACHING, AND SIMILAR RANGES, AMOUNTS, AND PROPORTIONS.
TABLE II. Catalyst Loading Calculation.
Total laminate thickness ranges from 50 micron to 250 microns (Lewinski et al. ¶20)
Density of Nafion is 1.58 g/cm3 which comprises the laminate (Leddy et al. pg. 3783: Introduction)
Lower coating weight of Nafion in Laminate = 1580 mg/cm3 x 0.005 cm = 7.9 mg/cm2
Upper coating weight of Nafion in Laminate = 1580 mg/cm3 x 0.0250 cm = 39.5 mg/cm2
Recombination Catalyst Loading Range in Laminate = 0.005 mg Pt/cm2 to 0.375 mg Pt/cm2 (see above for calculation in Claim 12).
Upper bound catalyst wt.% = (0.375 mg Pt/cm2)/(7.9 mg/cm2 Nafion + 0.375 mg/cm2) = 4.53 wt.%
Lower bound catalyst wt.% = (0.005 mg Pt/cm2)/(39.5 mg/cm2 Nafion + 0.005 mg/cm2) = 0.01 wt.%
Catalyst Weight % in the Laminate: 0.01 to 4.53 wt. %
19. Claims 26, and 27 are rejected under 35 U.S.C. 103 as being unpatentable over Lewinski et al. and Trogadas et al. and Du et al. as applied to Claim 23 above, in view of Stähler et al. and in further view of Park et al.
Lewinski et al. (US Pub. No. 2020/0102660 A1 – previously presented) is directed toward water electrolyzers comprising a recombination layer (Title and Abstract). Trogadas et al. (“Platinum supported on CeO2 effectively scavenges free radicals within the electrolyte of an operating fuel cell,” Chem. Comm. 2011, 47, 11549-11551 – previously presented) is directed at radical scavenging in operating fuel cells (pg. 11549: title). Du et al. (“Effects of ionomer and dispersion methods on the rheological behavior of proton exchange membrane fuel cell catalyst ink,” Int. J. Hydrogen Energy 2020, 45(53), 29430-29441 – previously presented) is directed toward dispersion methods for proton exchange membranes (pg. 29430: title). Stähler et al. (“A completely slot die coated membrane electrode assembly,” Int. J. Hydrogen Energy 2019, 44, 7053-7058 – previously presented) is directed toward slot die coating (pg. 7053: title). Park et al. (“Roll-to-roll production of catalyst coated membranes for low-temperature electrolyzers,” J. Power Sources 2020, article 228819, pages 1-9 – previously presented) is directed toward roll-to-roll production of electrolyzers (pg. 1: title).
Regarding Claim 26, Lewinski et al. in view of Trogadas et al. and Du et al. discloses the method per Claim 23 wherein providing the second layer membrane occurs by casting the slurry into a film using a microfilm applicator on a Kapton substrate (¶133). Lewinski et al. does not disclose deposition of the slurry onto a moving substrate via a roll-to-roll process, but rather application for a small-scale operation (Lewinski et al. ¶119-121).
Roll-to-roll operations for the high volume and high-quality production of membranes and electrodes for energy storage applications are fairly common (Park et al. pg. 2: Introduction). Often these processes utilize slot die coating (SDC) to apply coatings; for example, Stähler et al. discloses a SDC to apply a catalyst slurry (pg. 7053: title and abstract). Stähler et al. specifically discloses the application of an ionomer (e.g.: Nafion) slurry or an ionomer/catalyst slurry onto either a moving PTFE substrate (or another deposited layer) utilizing SDC (pg. 7055: Fig. 1). The slurry compositions of Stähler et al are analogous to the first layer membrane (ionomer only) and the second layer membrane (ionomer plus catalyst) of the present application. An example of a slot die coating process for the continuous production (i.e.: roll-to-roll) to deposit a catalyst slurry for use in membrane electrode assemblies is disclosed in Park et al. (pg.: 1 Abstract and Title). Park et al. teaches the direct deposition of catalyst/Nafion slurry deposited onto a substrate (or a membrane) (PARK-FIG. 1).
Since the second layer membrane slurry composition disclosed in Lewinski et al. comprises a mixture of Pt/ionomer like the slurries deposited using slot die coating in both Stähler et al. and Park et al., one ordinary skill in the art would reasonably expect to be able to modify some of the characteristics of the ink of Lewinski (e.g.: viscosity, concentrations, solvent, polymer wetting, polymer swelling, etc.) using the specific teachings in Park et al. to adapt the catalyst/ionomer for a slot die coating deposition process as part of a normal optimization procedure (see MPEP 2144.05 II). Therefore, it would be obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to modify the deposition method and slurry of Lewinski to enable using a continuous process (i.e.: roll-to-roll) to deposit a slurry onto a moving substrate by slot die coating as taught by the combination of Stähler et al. and Park et al. The resultant second layer membrane would be expected to be equivalent to the membrane layer made by other small-scale production processes (Park et al. pg. 7-8: Section 4. Conclusion).
Regarding Claim 27, Lewinski et el., Trogadas et al., Du et al., Stähler et al., and Park et al. together disclose the method as per Claim 26 wherein the providing the first layer membrane comprises a roll-to-roll process of depositing a slurry on the second layer membrane. Specifically, Stähler et al. teaches the deposition of an ionomer slurry (pg. 7055: Fig. 1-B1) which has the same composition as the first layer membrane applied to a catalyst/ionomer layer which has a similar composition to the second layer membrane. As described in detail above for Claim 26, the successive deposition process of the first layer membrane via a slurry on the second layer could be easily adapted to a roll-to-roll as disclosed in Park et al. by one of ordinary skill in the art before the effective filings date of the claimed invention.
20. Claim 28 is rejected under 35 U.S.C. 103 as being unpatentable over Lewinski et al., Trogadas et al., Du et al. Stähler et al., and Park et al. as applied to Claim 27 above, in further view of Endo et al.
Lewinski et al. (US Pub. No. 2020/0102660 A1 – previously presented) is directed toward water electrolyzers comprising a recombination layer (Title and Abstract). Trogadas et al. (“Platinum supported on CeO2 effectively scavenges free radicals within the electrolyte of an operating fuel cell,” Chem. Comm. 2011, 47, 11549-11551 – previously presented) is directed at radical scavenging in operating fuel cells (pg. 11549: title). Du et al. (“Effects of ionomer and dispersion methods on the rheological behavior of proton exchange membrane fuel cell catalyst ink,” Int. J. Hydrogen Energy 2020, 45(53), 29430-29441 – previously presented) is directed toward dispersion methods for proton exchange membranes (pg. 29430: title). Stähler et al. (“A completely slot die coated membrane electrode assembly,” Int. J. Hydrogen Energy 2019, 44, 7053-7058 – previously presented) is directed toward slot die coating (pg. 7053: title). Park et al. (“Roll-to-roll production of catalyst coated membranes for low-temperature electrolyzers,” J. Power Sources 2020, article 228819, pages 1-9 – previously presented) is directed toward roll-to-roll production of electrolyzers (pg. 1: title). Endo et al. (JP2006107914A – EPO translation, previously presented) is directed toward an electrolyte film for a solid polymer electrolyte having a sparingly soluble cerium compound (abstract).
Regarding Claim 28, Lewinski et al., Trogadas et al., Du et al, Stähler et al, and Park et al. together disclose the method of Claim 27, wherein the catalyst dispersion comprises a fluorinated ionomer (e.g.: Nafion) and a platinum-based recombination catalyst (e.g.: metallic platinum) (Lewinski et al. in ¶133) . However, Lewinski et al. and Trogadas et al. does not disclose the use of cerium hydroxide in said dispersion.
Endo et al. discloses the inclusion of sparingly soluble cerium compound to suppress the radical promoted degradation of the polymer electrolyte membrane as known for fluoropolymers (¶11). The sparingly soluble cerium compound is incorporated into the polymer dispersion by high-speed mixing and then cast to make a membrane (¶13-14). This membrane composition is resistant to peroxide or radical degradation (¶17) and the poorly soluble compound furnishes low levels of soluble Ce ions (¶18). The low solubility of the cerium compound, including cerium hydroxide (¶29), prevent significant migration of the cerium ions outside of the membrane (¶17). Endo et al. further discloses it is advantageous to have the cerium compounds present in the membrane layer(s) closest to the anode (such as the second layer membrane) as per ¶20.
It would be obvious for one of ordinary skill in the art before the effective filing date of the claimed invention to modify the dispersion composition of Lewinski et al., Trogadas et al., Stähler et al, and Park et al. with poorly soluble cerium hydroxide as discussed in Endo et al. with the reasonable expectation of providing an exchange membrane that has a second layer membrane that is very resistant to peroxide or radical decomposition due to the presence of cerium hydroxide (Endo et al. ¶17).
Response to Amendments
21. The objection to Claim 29 has been withdrawn due to the new limitation “of the exchange membrane” since relative meaning of 1 wt.% has been clarified.
22. The applicant has amended Claim 29 and so the rejection of said Claim under 112(b) is also withdrawn.
23. Two sets of claims are under examination in the instant application with Claim 1 and Claim 23 both being independent claims. Claims 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, and 31 all depend from Claim 1. Claims 24, 25, 26, 27, 28, 29, 30, and 32 all depend from Claim 23.
24. Applicant's arguments filed 17 March 2026 have been fully considered but they are not persuasive regarding Claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, and 31. The rejection of the above claims based (primarily) on the combination of Lewinski et al. in view of Trogadas et al. under 35 USC 103 is maintained.
In response to applicant's argument on pg. 11 that the examiner's conclusion of obviousness is based upon improper hindsight reasoning, it must be recognized that any judgment on obviousness is in a sense necessarily a reconstruction based upon hindsight reasoning. But so long as it takes into account only knowledge which was within the level of ordinary skill at the time the claimed invention was made, and does not include knowledge gleaned only from the applicant's disclosure, such a reconstruction is proper. See In re McLaughlin, 443 F.2d 1392, 170 USPQ 209 (CCPA 1971).
In response to applicant’s argument on pg. 9-10 that there is no teaching, suggestion, or motivation to combine the references, the examiner recognizes that obviousness may be established by combining or modifying the teachings of the prior art to produce the claimed invention where there is some teaching, suggestion, or motivation to do so found either in the references themselves or in the knowledge generally available to one of ordinary skill in the art. See In re Fine, 837 F.2d 1071, 5 USPQ2d 1596 (Fed. Cir. 1988), In re Jones, 958 F.2d 347, 21 USPQ2d 1941 (Fed. Cir. 1992), and KSR International Co. v. Teleflex, Inc., 550 U.S. 398, 82 USPQ2d 1385 (2007). In this case, combination of Lewinski et al. and Trogadas et al. is proper since both references are directed toward the reduction of H2 crossover in a catalyst coated membrane. Additionally, the incorporation of a metallic Pt catalyst would reasonably be expected to have the same recombination behavior whether the material is Pt black (in the instant application) or nanoparticulate metallic Pt supported on cerium oxide as in the case of (Lewinski et al. in view of) Trogadas et al.
25. Applicant’s arguments regarding Claims 23, 24, 25, 26, 27, 28, 29, 30, and 32 with respect to the rejections under 103 have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Lewinski et al. in view Trogadas et al. and Du et al.
The applicant amended Claim 23 to include a ball milling step for the preparation of the second layer membrane. This method of dispersion is well known for the formation of hybrid materials (i.e.: inorganic + organic) used in electrochemical cells, but was not explicitly disclosed in the combination of Lewinski et al. and Trogadas et al. As a result, the examiner modified the aforementioned combination with Du et al., which is a study directed at understanding the impact of dispersion method on catalyst slurries properties (pg. 29430: title and abstract). The new reasons for the new rejection are explained above in this office action.
Conclusion
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/KEVIN SYLVESTER/
Examiner, Art Unit 1794
/JAMES LIN/Supervisory Patent Examiner, Art Unit 1794
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