DETAILED ACTION
Application 18/083405, “PROTECTIVE LAYER ON ANODE-FACING SURFACE OF SEPARATOR FOR MITIGATING POLYSUFIDE SHUTTLING IN LITHIUM-BASED BATTERIES”, was filed with the USPTO on 12/16/22.
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
This Office Action on the merits is in response to communication filed on 3/15/24.
Claim Interpretation
Originally filed claim 2 requires, “wherein the protective layer comprises a non-porous polymer network”.
Typically, “non-porous” would be interpreted in the art to mean a structure without pores. Moreover, a “polymer network” would be interpreted as mutually exclusive with a non-porous structure because “polymer network” would be understood to be a body comprising a plurality of individual polymer bodies which are linked to form a network, which would necessarily define open cells therein, i.e. a porous structure.
Applicant’s specification (e.g. published paragraph [0039]) states, “More preferably, the polymeric network is non-porous, e.g., in the form of a network or matrix of interlocking polymer chains (“fibers”) ideally having negligible permissivity, permeability, etc. to lithium polysulfides.” This description suggests that non-porous in the context of the present claims should not be interpreted based on the conventional definitions provided above.
For the purposes of the art rejections below, a “non-porous” is interpreted to mean a structure which may comprise pores; however, the pores must be sufficiently small to inhibit the transport of lithium polysulfides therethrough.
Claim Rejections - 35 USC § 112
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.
Claims 2, 4-5, 10-12 and 17 is/are 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 pre-AIA the applicant regards as the invention.
Regarding claims 2 and 5, the meaning of “non-porous” is unclear.
Non-porous would normally be interpreted in the art to mean a body free of pores. However, applicant’s specification suggests that a structure made up of a matrix of interlocking polymer chains may be considered “nonporous” in the context of the current application (applicant’s published paragraph [0039]). Such a structure would not normally be considered non-porous therefore, the suggestion conflicts with the plain meaning of non-porous in the art. It is noted that although an example of what may be considered “non-porous” is presented, the section does not actually provide a limiting definition.
For the purposes of the art rejections below, “non-porous” is interpreted in a manner consistent with applicant’s specification (see Claim Interpretation section above), instead of the conventional meaning.
The rejection may be overcome by either i) clarifying the record with remarks made by applicant clearly defining “non-porous”, for example by confirming the Examiner’s interpretation or presenting a clear alternative interpretation, or ii) appropriately amending the claims.
The term “about” in claims 11-12 and 17 is a relative term which renders the claim indefinite. The term “about” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. It is not clear to what degree the numerical values are modified by the use of the term about.
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.
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
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 of this title, 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.
Claims 1, 3, 6-10, 13-15 and 18-20 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Kim (US 2021/0273296).
Regarding claim 1, Kim teaches a lithium-sulfur battery, comprising: an anode; a cathode; a separator positioned between the anode and the cathode (abstract, paragraphs [0035]); and a protective layer coating an anode-facing surface of the separator (The “functional separator… base separator… composite layer” of abstract, paragraph [0035]), wherein the protective layer is configured to mitigate polysulfide shuttling within the lithium-sulfur battery (paragraphs [0002, 0010]).
Regarding claims 3, 7-10, Kim remains as applied to claim 1. Kim further teaches wherein the protective layer comprises a polymeric component such as polyethylene oxide (“polyethylene oxide”, abstract, paragraph [0007, 0017]) and an ion-transporting component embedded in the polymeric component (paragraph [0017] describes an electrolyte solution [an ionic conductive component], which is embedded in the polymeric component via a conductive carbon). As to claim 3, the presence of the electrolyte therein renders the composite layer [protective layer] lithium ion conductive. As to claim 10, Kim further teaches LiTFSI as a possible salt of the electrolyte solution (paragraph [0068]).
Regarding claim 6, Kim remains as applied to claim 1. Kim further teaches wherein the protective layer is formed to a thickness within the range of from about 1 nm to about 20 microns (“0.1 to 15 μm”, paragraph [0027]).
Regarding claim 13-15, Kim remains as applied to claim 1. Kim further teaches wherein the protective layer is formed only on the anode-facing surface of the separator, such that the cathode-facing surface of the separator is characterized by absence of any protective coating formed thereon which is configured to mitigate lithium polysulfide shuttling within the lithium-sulfur battery (Kim implies providing the coating layer on a surface of the separator at abstract, paragraph [0008, 0059], and further teaches that the coating layer may be oriented to face the positive electrode, the negative electrode or both at paragraph [0016], the embodiment with the coating layer facing only the negative electrode implies the claimed structure with the cathode-facing surface of the separator absent of the coating layer).
Regarding claims 18-20, Kim remains as applied to claim 1 and 7-10. Kim teaches the structural features included in these method claims as previously described in the rejection of claims 1 and 7-10.
Kim further teaches the required process steps of forming a protective layer on one surface of a separator layer of a lithium-sulfur battery; and positioning the separator layer between an anode layer and a cathode layer of the lithium-sulfur battery (paragraph [0068]).
Claims 12 and 16 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kim (US 2021/0273296).
Regarding claim 12, Kim remains as applied to claim 7. Kim does not expressly teach wherein the polymeric component comprises one or more polymers characterized by a molecular weight in a range from about 100,000 g/mol to about 4,000,000 g/mol.
However, Kim does broadly teach a range of 200 to 10,000,000 for the molecular weight of the polymeric material (paragraph [0026]).
As described in MPEP 2144.05, a prima facie case of obviousness exists when the range of the prior art overlaps the claimed range, absent a showing of unexpected results. Thus, the claimed range is found to be prima facie obvious for overlapping the range taught by Kim at least at the 100,000 to 4,000,000 portion of the range.
Regarding claim 16, Kim remains as applied to claim 1. Kim is silent as to wherein the lithium-sulfur battery is characterized by an operational life cycle of over at least 250 cycles.
However, Kim does teach that the battery has improved capacity and lifetime due specifically to the use of the coating [protective layer] (paragraph [0002]).
The claimed limitation is found to be obvious over Kim because i) Kim teaches a battery having the same structure as that claimed (claim 1 is taught and no additional structural features are included in claim 16 which enable the desirable property); therefore, the same or similar properties would be expected, and ii) Kim expressly teaches that his battery is configured to have improved lifetime; therefore, an operational life cycle approaching or exceeding that required would be expected, or iii) it would have been obvious to optimize the battery to further increase the cycle lifetime above 250 cycles, since this limitation merely expresses a known desirable property, but no specific structure is claimed which is essential to achieve the property.
Claims 1-7, 9-10, 18 and 20 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Ma (US 2019/0194373).
Regarding claim 1, Ma teaches a lithium-sulfur battery (paragraph [0111]), comprising: an anode; a cathode; a separator positioned between the anode and the cathode (paragraphs [0110, 0118-0123, 0135]); and a protective layer (“membrane comprising a cross-linked polymeric material… battery comprising the membrane”, paragraph [0012-0013]) coating an anode-facing surface of the separator (paragraph [0149] suggests coating both sides of the separator), wherein the protective layer is configured to mitigate polysulfide shuttling within the lithium-sulfur battery (“polysulfide shuttling is suppressed”, paragraph [0136]).
Regarding claims 2 and 5, Ma remains as applied to claim 1. Ma further teaches wherein the protective layer comprises a non-porous polymeric network (Fig. 2; “a cross-linked network structure”, paragraph [0137]; interpreted to be “non-porous” because it is impermeable to polysulfide as described in paragraph [0041, 0136]).
Regarding claim 3, Ma remains as applied to claim 1. Ma further teaches wherein the protective layer is ionically conductive to lithium ions (paragraph [0114, 0147]).
Regarding claim 4, Ma remains as applied to claim 1. Ma further teaches wherein the protective layer is electrically non-conductive (the polymeric materials named, e.g. paragraph [0040], are electrically non-conductive by nature).
Regarding claim 6, Ma remains as applied to claim 1. Ma further teaches wherein the protective layer is formed to a thickness in a range from about 1 nm to about 20 microns (a 10 μm thickness embodiment is taught at paragraph [0117], lying within the claimed range so as to anticipate the claimed range).
Regarding claims 7 and 9-10, Ma remains as applied to claim 1. Ma further teaches wherein the protective layer comprises a polymeric component (paragraphs [0012-0013]), and an ion-transporting component embedded in the polymeric component comprising one or more materials configured to facilitate lithium-ion transport, such as LiPF6 (paragraph [0115]).
Regarding claims 18 and 20, Ma remains as applied to claim 1, 7 and 9-10. Ma teaches the structural features included in these method claims as previously described in the rejection of claims 1, 7 and 9-10.
Ma further teaches the required process steps of forming a protective layer on one surface of a separator layer of a lithium-sulfur battery; and positioning the separator layer between an anode layer and a cathode layer of the lithium-sulfur battery (paragraph [0135]).
Claims 6, 11 and 16 is/are rejected under 35 U.S.C. 103 as being unpatentable over Ma (US 2019/0194373).
Regarding claim 6, Ma remains as applied to claim 1. Ma does not expressly teach wherein the protective layer is formed to a thickness in a range from about 1 nm to about 20 microns.
However, Ma does broadly teach a range of about 10 μm to about 500 μm at paragraph [0117].
As described in MPEP 2144.05, a prima facie case of obviousness exists when the range of the prior art overlaps the claimed range, absent a showing of unexpected results. Thus, the claimed range is found to be prima facie obvious for overlapping the range taught by Ma at least at the 10 μm to about 20 μm portion of the ranges.
Regarding claim 11, Ma remains as applied to claim 7. Ma further does not expressly tea wherein the polymeric component and the ion-transporting component are present in a molar ratio of the polymeric component to the ion-transporting component range from about 8:1 to 20:1.
However, Ma does teach that the weight ratio of the polymer component to the ion conducting component may be 10:0.1 to 10:8, with exemplary suggested embodiments such as 10:0.1 and 10:0.2 which suggest a high relative polymer content, similar to that of the claimed range (paragraph [0074]).
The claimed range is found to be obvious, absent a showing of unexpected results, because Ma teaches a broad range which, although it’s given in weight ratio rather than molar ratio, appears to overlap the claimed range, especially at the low end of the Ma suggested range. It is noted that a 1:1 molar ratio of PEGDMA and VS (the exemplary species of Ma paragraph [0130] embodiment) corresponds to a PEGDMA:VS weight ratio of about 10:1.68; therefore, the lower end of the Ma ratio appears to include values overlapping the claimed range.
Regarding claim 16, Ma remains as applied to claim 1. Ma is silent as to wherein the lithium-sulfur battery is characterized by an operational life cycle of over at least 250 cycles.
However, Ma does teach that the battery has improved capacity and lifetime, including stable performance at least up to 100 cycles due specifically to the use of the membrane coating [protective layer] (paragraph [0149]; Figs. 16A, 16B).
The claimed limitation is found to be obvious over Ma because i) Ma teaches a battery having the same structure as that claimed (claim 1 is taught and no additional structural features are included in claim 16 which enable the desirable property); therefore, the same or similar properties would be expected, and ii) Ma expressly teaches that his battery is configured to have improved lifetime; therefore, an operational life cycle approaching or exceeding that required would be expected, particularly noting that Figs. 16A and 16B suggest relative stability at the high cycle number range approaching 100 cycles or iii) it would have been obvious to optimize the battery to further increase the cycle lifetime above 250 cycles, since this limitation merely expresses a known desirable property, but no specific structure is claimed which is essential to achieve the property.
Claims 17 is/are rejected under 35 U.S.C. 103 as being unpatentable over the combination of Kim (US 2021/0273296) and Chung (US 2022/0293914).
Claims 17 is/are rejected under 35 U.S.C. 103 as being unpatentable over the combination of Ma (US 2019/0194373) and Chung (US 2022/0293914).
Regarding claim 17, Kim remains as applied to claim 1. Alternatively, Ma remains as applied to claim 1.
Neither of Kim and Ma appear to teach wherein the cathode is characterized by a loading of active material of at least about 5 mg/cm2 or more.
In the battery art, Chung teaches that a lithium sulfur battery may be configured to have a loading of 5 mg/cm2 provides higher energy density than lower loading amounts, but may be associated with polysulfide deterioration (paragraph [0010]). Chung further teaches inventive lithium sulfur batteries with cathodes configured to enable higher sulfrur loading such as 14 mg/cm2 (paragraph [0109]).
It would have been obvious to a person having ordinary skill in the art at the time of invention to configure the battery to have an active material loading of 5 mg/cm2 or more, for the benefit of achieving desirable energy density as taught by Chung. It is noted that this desirable loading may be achieved because the batteries of Kim and Ma are each resistant to polysulfide damage as previously described, or could be achieved by further modifying the cathode to enable the higher loading as taught by Chung.
Relevant or Related Art
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure, though not necessarily pertinent to applicant’s invention as claimed.
Lu (US 2018/0241039) -lithium sulfur battery including background teaching that lithium polysulfides compromise cycle life;
He (US 2020/0028178) -lithium sulfur battery comprising anode-protecting layer;
Beck (US 2023/0216081) -general teaching that separator should be dimensionally configured to balance lithium ion flux and impedance to poysulfide migration;
Burkhardt (US 2025/0260001) -lithium sulfur battery comprising separator configured to be permeable to lithium ion and less permeable to polysulfide ions.
Conclusion
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/JEREMIAH R SMITH/Primary Examiner, Art Unit 1723