DETAILED ACTION
Application 17/931903, “LITHIUM METAL SECONDARY BATTERY”, was filed with the USPTO on 9/14/22 and claims priority from a foreign application filed on 10/15/21.
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 4/27/26.
Response to Arguments
Applicant’s arguments filed on 4/27/26 have been fully considered, but are not persuasive. Applicant presents the following arguments.
The claimed invention has the effect of providing a lithium metal secondary battery having improved durability. In response, patentability under US practice is not guided by, or at least is not limited by, the problem to be solved. Instead, the prior art must be considered even if the goal of the prior art is to achieve a different advantage, but nevertheless achieves the invention claimed by applicant. Moreover, it has been held that the recognition of another advantage which would flow naturally from following the suggestion of the prior art cannot be the basis for patentability when the differences would otherwise be obvious. See Ex parte Obiaya, 227 USPQ 58, 60 (Bd. Pat. App. & Inter. 1985). In this case, the invention is found to be obvious for the reasons set forth in the rejection, and the prior art is not required to teach the same technical effect. It is noted that Zhamu does teach his batteries have high capacity and durability (paragraph [0012]). There is no evidence of record tending to demonstrate that any advantages discovered by applicant are substantially different from or more significant than, the expected advantages and results suggested by the prior art.
Applicant believes that it was common technical knowledge at the time of filing that a lithium salt refers to a salt containing lithium ions. In response, this belief conflicts with the express disclosure of Shin2, which is not rebutted by any evidence. The arguments of counsel cannot take the place of evidence in the record (MPEP 716.01(c) II).
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, 6-7 and 9-10 is/are rejected under 35 U.S.C. 103 as being unpatentable over the combination of Zhamu (US 2019/0393508), Fuller (J. Fuller et al; “Ionic Liquid‐Polymer Gel Electrolytes”; 1997 J. Electrochem. Soc. 144 L67) and Shin2 (US 2009/0286163).
Regarding claim 1, 9 and 10, Zhamu teaches a lithium metal secondary battery (title, Fig. 2), comprising: a positive electrode (“cathode active material layer” of Fig. 2); a negative electrode current collector (“anode current collector” of Fig. 2); an electrolyte layer (“porous separator” of Fig. 2, which comprise an electrolyte to facilitate ion transfer between electrodes; see also paragraph [0064]) provided between the positive electrode and the negative electrode current collector; an intermediate layer (“sulfonated elastomer composite-based protective layer” of Fig. 2) provided between the positive electrode and the negative electrode current collector and comprising an expandable and contractible (“The sulfonated elastomer composite can expand and shrink responsive to the shrinkage and expansion of the anode active material layer”, paragraph [0134]), three-dimensional structure (“sulfonated elastomeric matrix material”, paragraph [0013]); and a liquid electrolyte held within the expandable and contractible, three-dimensional structure (paragraph [0087-0089] describe a liquid electrolyte, i.e. a salt with a solvent, present in the sulfonated elastomer in a polymerized state; see also paragraph [0133]).
Zhamu further teaches wherein the electrolyte layer is provided between the positive electrode and the intermediate layer (see arrangement of Fig. 2).
Zhamu does not appear to teach wherein the expandable and contractible, three-dimensional structure is a polymer gel electrolyte consisting of an ionic liquid, a lithium salt, and a fluororesin, wherein the fluororesin is polyvinylidene fluoride or a vinylidene fluoride-hexafluoropropylene copolymer, and as required by the 4/27/26 amendment, wherein the ionic liquid is a species such as 1-ethyl-3 methylimidazolium bis(flurosulfonyl)imide and the lithium salt is a species such as lithium bis(trifluoromethylsulfonyl)imide [included in new claims 9 and 10].
In the battery art, Fuller teaches an ionic liquid-polymer gel electrolyte (title), characterized by exhibiting desirable properties such as a rubbery/flexible structure, high ionic conductivity, thermal performance stability, inertness and low volatility, and excellent long-term storage characteristics (abstract; Introduction first paragraph; page L69 at third paragraph). Fuller further teaches the ionic liquid-polymer gel electrolyte consisting of an ionic liquid, a common nonaqueous support electrolyte salt and a fluororesin (PVDHFP, EMIPF6, TEABF4, page L69 at third paragraph).
It would have been obvious to a person having ordinary skill in the art at the time of invention to utilize a polymer gel electrolyte consisting of an ionic liquid, a salt, and a fluororesin, wherein the fluororesin is polyvinylidene fluoride or a vinylidene fluoride-hexafluoropropylene copolymer, as the expandable and contractible three-dimensional structure, for the benefit of employing a polymer electrolyte having the various desirable properties specified by Fuller.
As to the requirement that the salt is a lithium salt, Fuller teaches TEABF4 as the support salt.
In the battery art, Shin2 characterizes TEABF4 as a “lithium salt”, even though it does not expressly include lithium ions (Shin2 at his claim 17). Therefore, Fuller’s disclosure of TEABF4 can reasonably be mapped to the claimed “lithium salt” for the ionic liquid of claim 1.
Further regarding the specifically claimed lithium salt species, such as lithium bis(trifluoromethylsulfonyl)imide [included in the group of claims 9 and 10], the skilled artisan at the time of invention would have understood TEABF4 (taught by Fuller) and a lithium salt, such as lithium bis(trifluoromethylsulfonyl)imide [LiTFSI] (taught by Zhamu e.g. at [0024]) to be substitutable alternatives capable of providing the needed ionic conductivity for lithium battery electrolyte applications.
See also Shin2 which teaches TEABF4 and LiTFSI as alternative suitable lithium salts (Table 2) for ionic liquid type electrolyte systems (abstract, paragraphs [0057-0066]).
Therefore, it would have been obvious to a person having ordinary skill in the art at the time of invention to employ a lithium salt such as lithium bis(trifluoromethylsulfonyl)imide as the salt for the ionic liquid, since this salt is suitable for battery applications, and is an obvious variant of the TEABF4 expressly taught by Fuller. As described in MPEP 2141, a prima facie case of obviousness exists for the simple substitution of one known element for another to obtain the predictable result.
As to the requirement that the ionic liquid is a species such as 1-ethyl-3 methylimidazolium bis(flurosulfonyl)imide, Fuller teaches the 1-ethyl-3-methyl imidazolium cation (see Introduction, Experimental), but for example teaches the anion for example as triflate [CF3SO3-] ion (see Introduction, Experimental) and does not appear to teach the ionic liquid bis(fluorosulfonyl)imide anion, specifically.
However, Shin2 further teaches that the species of anion useful for ionic liquid include anions such as bis(trifluoro methane sulfonyl)imide and triflic acid [CF3SO3-] (paragraph [0059]). Shin2 further teaches that the cation of the ionic liquid may be N-methyl-N-alkyl [ethyl]-imidazolium (paragraph [0056]), and specifically teaches N-methyl-N-ethyl imidazolium TFSI as a known useful ionic liquid (paragraph [0080]).
Therefore, it would have been obvious to a person having ordinary skill in the art at the time of invention to employ a species such as 1-ethyl-3-methylimidazolium bis(flurosulfonyl)imide as the ionic liquid, since this is a known or suggested ionic for battery applications, and is an obvious variant of the ionic liquids expressly taught by Fuller. As described in MPEP 2141, a prima facie case of obviousness exists for the simple substitution of one known element for another to obtain the predictable result.
Regarding claim 3, the cited art remains as applied to claim 1. Zhamu further teaches wherein the electrolyte layer is a solid electrolyte layer (paragraphs [0045, 0098]).
Regarding claim 6, the cited art remains as applied to claim 1. Claim 6 further requires wherein the expandable and contractible, three-dimensional structure comprises a composition comprising the fluororesin, having undergone compression molding, and then having undergone impregnation with a liquid comprising the ionic liquid.
However, as described in MPEP 2113, “The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process”. Here, the recitation as worded does not expressly require, nor otherwise imply, any particular structure which substantially differentiates the claimed intermediate layer from that of the cited art.
Regarding claim 7, the cited art remains as applied to claim 1. Zhamu further teaches wherein the intermediate layer further comprises lithium metal (paragraph [0076] describes lithium transferring from the cathode toward the anode current collector as an initial charging/deposition process. This results in a structure with lithium metal integrated with the three-dimensional structure, similar to the process described by applicant at applicant’s published paragraph [0026]).
Claims 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over the combination of Zhamu (US 2019/0393508), Fuller (J. Fuller et al; “Ionic Liquid‐Polymer Gel Electrolytes”; 1997 J. Electrochem. Soc. 144 L67) and Shin2 (US 2009/0286163), and further in view of Singh (USP 10566659), Kuwajima (US 2020/0243911) or Takami (US 2022/0255133).
Regarding claim 8, the cited art remains as applied to claim 7. Zhamu further teaches wherein the intermediate layer has the expandable and contractible, three-dimensional structure integrated with at least some of the lithium metal (paragraph [0076] describes lithium transferring from the cathode toward the anode current collector as an initial charging/deposition process. This results in a structure with lithium metal integrated with the three-dimensional structure, similar to the process described by applicant at applicant’s published paragraph [0026]), but does not appear to teach wherein the layer has a fluorine content of 2.0 at% or more.
In the battery art, Singh teaches adding an additive to a molten-salt electrolyte [i.e. an ionic salt electrolyte], wherein the additive may include 10% of a fluorine containing additive, for example, trifluoromethylethyl methyl carbonate, for the benefit of decreasing viscosity and reducing melt temperature (c6:8-25).
In the battery art, Kuwajima teaches that a fluorine content of preferably 12% by mass or more may be added to an electrolyte composition in order to increase the viscosity thereof (paragraph [0103]), with an exemplary electrolyte composition being an ionic liquid (paragraph [0163]).
In the battery art, Takami teaches that a fluorine compound may be added to a composition in an amount of 10 to 30 wt% for the benefit of improving viscosity and low-temperature performance properties thereof (paragraph [0042]).
It would have been obvious to a person having ordinary skill in the art at the time of invention to include 2 at% or more of fluorine in the intermediate layer for the benefit of improving the viscosity and/or low temperature properties of the ionic liquid component of the layer. The claimed range is found to be obvious because the cited art teaches fluorine content as a result-effective variable and suggests ranges which appear to overlap the claimed range.
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.
Kano (US 2022/0407047) teaches battery comprising an expanding layer 222 comprising lithium alloy;
Shembel (US 2003/0031933) teaches that thickness of polymer electrolyte layer and standard separators can change during charge/discharge cycle;
He (US 2020/0028178) lithium battery comprising elastomer layer than expands and shrinks in respond to anode active material layer;
Pan (US 2021/0218050) battery comprising expandable, contractable polymer gel electrolyte intermediate layer.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JEREMIAH R SMITH whose telephone number is (571)270-7005. The examiner can normally be reached Mon-Fri: 9 AM-5 PM (EST).
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Tiffany Legette-Thompson can be reached on (571)270-7078. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/JEREMIAH R SMITH/Primary Examiner, Art Unit 1723
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