DETAILED ACTION
Response to Amendment
Applicant’s amendment filed on December 31, 2025, has been entered. Claims 1, 3, 5, and 13-15 are pending in the application. Applicant’s amendment to the claims has overcome the previous rejection of record under 35 U.S.C. 112.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 5, 13, 14, and 15 are rejected under 35 U.S.C. 103 as being unpatentable over US 20040048154 A1 (Jung ‘154) in view of US 20190157665 A1 (Pope ‘665) or Polycation Binders: An Effective Approach toward Lithium Polysulfide Sequestration in Li–S Batteries (Su 2017).
Regarding claim 1, Jung ‘154 teaches a positive electrode of a lithium secondary battery (an additive used in a positive electrode of a lithium-sulfur battery, wherein the additive physically and chemically interacts with a binder to enhance adhesion of the binder; [0023]) comprising:
a positive electrode active material (the positive electrode includes a positive active material including elemental sulfur, a sulfur-based compound, or a mixture thereof; [0027]),
a conductive material (the positive electrode includes a conductor, wherein the conductor is a conductive material, for example, a carbon-based material; [0027] – [0028]),
and a binder comprising a polymer comprising a carboxylate group wherein the polymer comprising the carboxylate group comprises poly(acrylic acid) (the polymer comprising a carboxylate group corresponds to the binder being polyacrylic acid in [0029] of Jung ‘154; see also [0016] of the published patent application, i.e., US 20220209237); and a cationic polymer (a polymer that is cationic; [0023]),
wherein a content of the cationic polymer is 5% by weight to 25% by weight based on a total weight of the binder (the positive electrode preferably includes 5 to 50 parts by weight of the additive based on 100 parts by weight of the binder, wherein the additive improves adhesion of the binder; [0030]),
wherein the polymer comprising the carboxylate group and the cationic polymer are present in a weight ratio of 70:30 to 95:5 (in example 1 of [0047] of Jung ‘154, the positive electrode includes 1 g of polyvinyl pyrrolidone and 0.05 g of polyethyleneimine, such that, the 1 g of polyvinyl pyrrolidone ([0029]) constituting the polymer comprising a carboxylate group and the 0.05 g of polyethyleneimine constituting the cationic polymer are present in a weight ratio of 95:5 because 1 g out of a total 1.05 g equates to 95% for the polymer comprising the carboxylate group and 0.05 g out of a total 1.05 g equates to 5% for the cationic polymer), and
wherein the positive electrode active material is present in the form of a sulfur-carbon composite (in example 1, carbon black and elemental sulfur were added to the mixed binder liquid and were distributed to prepare a composite slurry for the positive electrode of a lithium-sulfur battery; [0047]).
As set forth in MPEP 2144.05, in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art”, a prima facie case of obviousness exists (In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990)).
Therefore, prior to the effective filing date of the claimed invention, it would have been obvious to a person of ordinary skill in the art, to include the cationic polymer in an amount of 5% by weight to 30% by weight based on a total weight of the binder, to improve adhesion of the binder in the electrode of a lithium secondary battery, as taught by Jung ‘154.
Jung ‘154 discloses that polyethyleneimine is an example of the cationic polymer additive ([0023]), however, Jung ‘154 does not disclose that the cationic polymer comprises at least one selected from the group consisting of poly[(2-ethyldimethylammonioethyl methacrylate ethyl sulfate)-co-(1-vinylpyrrolidone)] and poly(diallyldimethylammonium chloride).
Pope ‘665 discloses a cathode for use in a lithium-sulfur (Li—S) battery comprising a graphene material (GM) ([0004]). The cathode also comprises a nitrogen-containing polymer (N-polymer) and sulfur (S) ([0004]). The N-polymer(s) include a high density of nitrogen-containing groups such as polyethyleneimine (PEI), poly (diallyl dimethyl ammonium chloride), or poly(vinylamine)hydrochloride ([0004]; [0025]; & [0026]).
Therefore, it would have been obvious to a person of ordinary skill in the art, prior to the effective filing date of the claimed invention, to select poly (diallyl dimethyl ammonium chloride) as the cationic polymer, as suggested by Pope ‘665, in the binder for the electrode of the lithium secondary battery, as taught by Jung ‘154, because the selection of a known material, which is based upon its suitability for its intended use, is within the ambit of one of ordinary skill in the art. See In re Leshin, 125 USPQ 416 (CCPA 1960) (see MPEP § 2144.07).
Su 2017 studied lithium polysulfide sequestration by polymeric binders in lithium-sulfur battery cathodes, wherein polycations can effectively adsorb lithium polysulfides via Coulombic attraction between the positive charged backbone and the polysulfide anions (abstract). In particular, poly[(2-ethyldimethylammonioethyl methacrylate ethyl sulfate)-co-(1-vinylpyrrolidone)] (polyquaternium D11) was studied as one of the representative polycation binders (left column of page 2592). Polyquaternium D11 is commercially available (left column of page 2592). D11 demonstrated a clear advantage over polyvinylpyrrolidone (PVP) (abstract) in terms of overall capacity and cycle stability in the sulfur cathode when used as the binder (right column of page 2592).
Therefore, it would have been obvious to a person of ordinary skill in the art, prior to the effective filing date of the claimed invention, to select poly[(2-ethyldimethylammonioethyl methacrylate ethyl sulfate)-co-(1-vinylpyrrolidone)] (polyquaternium D11) as the cationic polymer, as suggested by Su 2017, in the binder for the electrode of the lithium secondary battery, as taught by Jung ‘154, because the selection of a known material, which is based upon its suitability for its intended use, is within the ambit of one of ordinary skill in the art. See In re Leshin, 125 USPQ 416 (CCPA 1960) (see MPEP § 2144.07).
Regarding claim 5, Jung ‘154 teaches the binder for the electrode of the lithium secondary battery according to claim 1, wherein the cationic polymer has a weight average molecular weight of 3,000 to 1,000,000 (the weight-average molecular weight of the polyethyleneimine is 20,000 to 150,000; [0024] of Jung ‘154).
As set forth in MPEP 2144.05, in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art”, a prima facie case of obviousness exists (In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990)).
Regarding claim 13, Jung ‘154 teaches the positive electrode for the lithium secondary battery according to claim 1, wherein a content of the binder is 2% by weight to 10% by weight based on a total weight of a base solid content included in the positive electrode for the lithium secondary battery (in example 1 of [0047] of Jung ‘154, the base solid content of the positive electrode includes 1 g of polyvinyl pyrrolidone, 0.05 g of polyethyleneimine, 2 g of carbon black, and 16 g of elemental sulfur, such that, the 1 g of polyvinyl pyrrolidone ([0029]) constituting the polymer comprising a carboxylate group together with the 0.05 g of polyethyleneimine constituting the cationic polymer is equal to 5.5% of the total weight of the solid content included in the positive electrode, because the binder makes up 1.05 g out of the total 19.05 g of base solid content).
As set forth in MPEP 2144.05, in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art”, a prima facie case of obviousness exists (In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990)).
Regarding claim 14, Jung ‘154 teaches the positive electrode for the lithium secondary battery according to claim 1, wherein the binder comprises the polymer comprising the carboxylate group and the cationic polymer, and a content of the cationic polymer is 0.1% by weight to 3% by weight based on a total weight of a base solid content included in the positive electrode for the lithium secondary battery (in example 1 of [0047] of Jung ‘154, the base solid content of the positive electrode includes 1 g of polyvinyl pyrrolidone, 0.05 g of polyethyleneimine, 2 g of carbon black, and 16 g of elemental sulfur, such that, the 0.05 g of polyethyleneimine constituting the cationic polymer is equal to 0.26% of the total weight of the solid content included in the positive electrode, because the cationic polymer makes up 0.05 g out of the total 19.05 g of base solid content).
As set forth in MPEP 2144.05, in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art”, a prima facie case of obviousness exists (In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990)).
Regarding claim 15, Jung ‘154 teaches a lithium secondary battery comprising the positive electrode (a lithium-sulfur battery having a positive electrode; [0036] of Jung ‘154) for the lithium secondary battery according to claim 1 (see the rejection of claim 10 above), a negative electrode (a negative electrode 12; [0036] of Jung ‘154), a separator interposed between them (a separator 13 interposed between the positive electrode 11 and the negative electrode 12; [0036] of Jung ‘154), and an electrolyte (an electrolyte; [0036] of Jung ‘154).
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over US 20040048154 A1 (Jung ‘154) in view of US 20190157665 A1 (Pope ‘665) or Polycation Binders: An Effective Approach toward Lithium Polysulfide Sequestration in Li–S Batteries (Su 2017), and further in view of US 20170324094 A1 (Sugiyama ‘094).
Regarding claim 3, Jung ‘154 teaches the positive electrode of the lithium secondary battery according to claim 1, but does not specifically disclose that the polymer comprising the carboxylate group has a weight average molecular weight of 50,000 to 5,000,000.
Sugiyama ‘094 discloses a polymer compound for use as a binder (abstract). The polymer compound includes polyacrylic acid having a weight average molecular weight in a range of 50,000 to 1,500,000 ([0035] – [0036]).
Therefore, it would have been obvious to a person of ordinary skill in the art, prior to the effective filing date of the claimed invention, for the polymer comprising the carboxylate group (polyacrylic acid) in the binder, as taught by Jung ‘154, to have a weight average molecular weight of 50,000 to 1,500,000, which overlaps with the claimed range of claim 3 (50,000 to 5,000,000), as suggested by Sugiyama ‘094.
As set forth in MPEP 2144.05, in the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art”, a prima facie case of obviousness exists (In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990)).
Response to Arguments
Applicant's arguments filed on December 31, 2025, have been fully considered.
Applicant argues that the claimed binder produces unexpected results, because the claimed binder, corresponding to examples 1-6 and 10 of the invention has superior positive electrode bonding force, as compared to the positive electrodes of Comparative Examples 1-4.
In particular, [0143] of the PG Pub for this application (US 20220209237 A1) states that the positive electrodes of the Examples comprising the binder produced by mixing a small amount of cationic polymer with the polymer including the carboxylate group have excellent positive electrode bonding force, as compared to the positive electrode of the Comparative examples that do not contain the cationic polymer.
Likewise, Jung discloses that an additive improves adhesion of the binder by allowing an amount of the binder to decrease and allowing an amount of the positive active material to increase ([0030]). Thus, the lithium-sulfur battery exhibits high capacity ([0030]). However, excess additive prevents an increase in the amount of the positive active material, and hence limits capacity ([0030]). Therefore, Jung recognizes that a binder including a controlled amount of an additive (not in excess) for a lithium-sulfur battery has improved adhesion and high capacity. The binder may be polyacrylic acid, and the additive may be an additive which physically and chemically interacts with a binder to improve the adhesion of the binder ([0078]).
While Jung does not disclose that the additive may be poly[(2-ethyldimethylammonioethyl methacrylate ethyl sulfate)-co-(1-vinylpyrrolidone)] or poly(diallyldimethylammonium chloride), Jung discloses that the additive may be polyethyleneimine ([0023]).
Pope discloses a binder comprising a cationic polymer such as polyethyleneimine (PEI), poly (diallyl dimethyl ammonium chloride), or poly(vinylamine)hydrochloride, which is suitable for use in cathode of a lithium-sulfur (Li—S) battery ([0004]; [0025]; & [0026]).
Su also discloses a binder comprising a cationic polymer such as poly[(2-ethyldimethylammonioethyl methacrylate ethyl sulfate)-co-(1-vinylpyrrolidone)], which is suitable for use in a lithium-sulfur battery (left column of page 2592 & abstract).
Pope and Su both disclose representative binders containing a cationic polymer. Jung, as discussed above, teaches that including a binder containing a cationic polymer as an additive in addition to a poly(acrylic acid) binder, in a controlled amount (not in excess), improves the adhesion of the binder by allowing an amount of the binder to decrease and allowing an amount of the positive active material to increase. Thus, a skilled artisan would have found it obvious to select poly[(2-ethyldimethylammonioethyl methacrylate ethyl sulfate)-co-(1-vinylpyrrolidone)] or poly(diallyldimethylammonium chloride) as the additive, corresponding to the binder containing a cationic polymer, instead of polyethyleneimine, because the selection of a known material, which is based upon its suitability for its intended use, is within the ambit of one of ordinary skill in the art. See In re Leshin, 125 USPQ 416 (CCPA 1960) (see MPEP § 2144.07).
Therefore, Applicant’s argument that the claimed binder produces unexpected results over the previously cited references is not persuasive.
Applicant additionally argues that Example 1 of Pope differs from the claimed positive electrode. However, arguments directed to Example 1 of Pope are not persuasive. Examiner relies on example 1 in Jung, not Pope, to teach the structure of the positive electrode active material present in the form of a sulfur-carbon composite. Pope is relied on to disclose a suitable binder comprising a cationic polymer.
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/TAYLOR HARRISON KRONE/Examiner, Art Unit 1725
/NICOLE M. BUIE-HATCHER/Supervisory Patent Examiner, Art Unit 1725