DETAILED ACTION
Application 17/281159, “METHODS OF MAKING AND USING AN ELECTROCHEMICAL CELL COMPRISING AN INTERLAYER”, is the national stage entry of a PCT application filed on 10/1/19 and claims priority from a provisional application filed on 10/2/18.
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 5/18/26.
Response to Arguments
Applicant’s arguments filed on 5/18/26 have been fully considered, but are not persuasive. Applicant presents the following arguments.
There is no reasonable expectation of success in combining Wachsman with Roumi [to provide a lithium-stuffed garnet type solid electrolyte] because Roumi never mentions crystalline solid-state electrolytes. Instead, Roumi uses only solid electrolytes having different which are more mechanically robust than, and may have other advantages compared to, the Wachsman electrolytes. In response, Wachsman teaches that lithium-stuffed garnet is useable as the solid electrolyte of a lithium battery, which is sufficient to support the obviousness modification of Roumi based on a simple substitution type rationale (MPEP 2141). Additionally, Wachsman teaches that certain advantages are associated with lithium-stuffed garnet electrolyte, which supports a teaching-suggestion-motivation type rationale for substitution of the electrolyte. Roumi’s teaching of different advantages for the solid electrolytes of his disclosure does not negate these rationales for finding of obviousness. Roumi’s disclosure does not teach away from such a modification because it does not mention Garnet type electrolytes and/or explain why modification in view of Wachsman, specifically, would not provide functional battery embodiments.
Roumi focuses on benefits of amorphous solid electrolytes, such as resistance to cracking by use of amorphous electrolytes; therefore, a skilled artisan would not replace the Roumi electrolyte with a lithium-stuffed garnet type electrolyte which is crystalline. In response, it has been held that “The use of patents as references is not limited to what the patentees describe as their own inventions or to the problems with which they are concerned. They are part of the literature of the art, relevant for all they contain.” Here, Roumi’s focus on the benefits of amorphous solid electrolyte does not limit it’s use in obviousness rejections to embodiments which retain the amorphous solid electrolyte. The guidelines for demonstration of obviousness set forth in MPEP 2141 allow for substitution of Roumi’s electrolyte, even if disclosed by Roumi as desirable, with a different kind of electrolyte that was known at the time of invention and/or desirable for other reasons.
Garnets do not undergo plastic deformation at high temperatures and unexpectedly reduce capacity fade at high discharge-charge rates, which is not disclosed by Roumi; therefore, substitution of a Wachsman garnet solid electrolyte with the Roumi solid electrolyte would not yield predictable results and/or reasonable expectation of success. In response, the predictable result is that a suitable lithium battery would be achieved by the substitution, and that the advantages set forth in Wachsman would also be achieved. Roumi does not analyze the particular solid electrolytes of Wachaman; therefore, there is no persuasive evidence of record that that the proposed modification would not provide these predictable results. Moreover, even if the record demonstrate that the combined embodiment utilizing Wachsman’s garnet electrolyte would be more prone to cracking, this does not negate the obviousness of the combination as the combination may provide other benefits suggested by Wachsman. As described in MPEP 2123 II, “A known or obvious composition does not become patentable simply because it has been described as somewhat inferior to some other product for the same use.” Here, the garnet solid electrolyte is known for use as a battery electrolyte in view of Wachsman, and a Roumi teaching that garnet solid electrolyte was prone to cracking and therefore inferior to amorphous solid electrolytes which resist cracking would not cause the known garnet solid electrolyte to become a patentable element of the claimed invention and/or negate its use in an obvious combination. The expected success remains that a functional battery can be formed using the garnet solid electrolyte disclosed by Wachsman, even if that electrolyte is more susceptible to cracking that other types of solid electrolyte.
Applicant argues that unexpected results are associated with the claimed invention and points to the disclosure of Roumi and applicant’s Example 6 as evidence of the unexpected results. More specifically, applicant points out that Example 6 demonstrates that cycling at 1 C for over 300 cycles leads to a discharge capacity of only about 15%, a result which is not predictable in view of Roumi. In response, it has been held that to be of probative value, evidence of unexpected results must [among other things] at least i) be commensurate in scope with the claimed invention, and ii) demonstrate that the benefit associated with the claimed invention is actually surprising or unexpected and is more significant that the benefit disclosed in the prior art (MPEP 716.02d, 716.02c). Here, as to i), applicant’s Example 6 is drawn to a specific embodiment comprising particular materials and particular dimensions, but claim 1 is drawn to a broader invention covering a range of possibilities. There is no evidence of record demonstrating that any improvement associated with Example 6 would be expected by the skilled artisan over the breadth of claim 1. Thus, the evidence is insufficient in consideration of i). As to ii), Wachsman teaches that a garnet solid electrolyte may be used for benefits such as desirable safety, high electrochemical stability, and resistance to dendrite propagation. There is no evidence tending to show that the benefit noted in applicant’s Example 6, i.e. improved capacity retention, is of greater significance than the benefits which are expected in view of Wachsman. It is noted that counsel’s argument that results are unexpected or particularly significant cannot take the place of evidence in the record (MPEP 716.01c).
Applicant’s request for rejoinder is presently moot as the elected invention has not been found allowable.
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, 4, 16-18, 20-21, 23-24, 40, 42 and 47-51 is/are rejected under 35 U.S.C. 103 as being obvious over Roumi (US 2013/0224632) the combination of Roumi (US 2013/0224632) and Wachsman (US 2021/0083320).
Regarding claims 1, 16-18, 24 and 51, Roumi teaches a electrochemical stack (e.g. Figure 47) comprising the following components in the stated order:
a negative electrode current collector [NECC] (“anode current collector”, Fig. 47);
a Li metal negative electrode (“Li-metal”, Fig. 47);
a metal interlayer (“conductive layer… Ni”, Fig. 47);
a solid-state electrolyte separator (“separator… solid electrolyte”, Fig. 47); and
a cathode that comprises NMC or another claimed species (“NMC cathode”, Fig. 47; see also paragraph [0059]).
Alternatively, consider Figures 10M and 10P which suggest the claimed structure with “thin electronic coating” and “ionic/electronic conductive layer” of the respective figures being readable on the interlayer. Current collectors are omitted from these schematic diagrams, but are obvious to include, as in Fig. 47, in order to facilitate electron transfer from the electrodes to an external load.
Roumi further teaches wherein the interlayer is laminated to the solid-state separator (Fig. 47; paragraph [0071] where the “electronically and ionically conductive layer” corresponds to an interlayer).
The Figure 47 embodiment is a lithium battery which includes a lithium metal layer between the interlayer and a NECC [negative electrode current collector], but is silent as to the technique used to form the Figure 47 structure and the structure is not expressly disclosed to include the interlayer adjacent to but not bonded to the NECC.
However, it was known in the art that lithium metal batteries may be constructed by adding a lithium metal layer during the construction, or may be constructed by assembling the battery in a state without a lithium metal layer, then forming the lithium metal layer on a negative electrode current collector in a first charging step. For example, see Roumi at paragraph which describes a battery formed using LiCoO2 cathode and depositing a lithium metal layer on a copper wire current collector during a first charging step to form the lithium metal anode (paragraph [0316]).
Therefore, it would have been obvious to a person having ordinary skill in the art to form the electrochemical stack with the interlayer adjacent, but not bonded to the NECC, so that lithium metal layer could be formed during an initial charge, such as in the paragraph [0316] embodiment. Such an embodiment is found to be obvious at least because it merely combines teachings of Roumi that are separately disclosed but combinable together in a single embodiment to yield predictable results.
It is noted that Roumi teaches that a conductive layer disposed on a separator may facilitate more uniform lithium deposition during charging (paragraph [0312]), suggesting that the interlayer is compatible and/or useful for embodiments which form lithium layer during charging.
Regarding the 5/18/26 amendment to claim 1 and dependent claims 16-18 and 24, Roumi does not appear to teach wherein the electrolyte separator comprises lithium-stuffed garnet such as Li7La3Zr2O12 [LLZ] [readable on claims 16-18], and wherein the solid-state electrolyte separator has a thickness from about 1 to 200 μm [or more narrowly between 10 and 100 μm as in claim 24].
In the battery art, Wachsman teaches a separator comprising Li7La3Zr2O12 (paragraph [0053]), which is configured to provide high ionic conductivity associated with LLZ and to block dendrite propagation (paragraph [0115]). Wachsman further teaches that LLZ type garnet materials have various advantages such as safety high conductivity (paragraph [0004]).
It would have been obvious to a person having ordinary skill in the art to utilize a lithium-stuffed garnet such as Li7La3Zr2O12 since this material is desirable for use as an electrolyte separator material due to its high ionic conductivity and other desirable properties taught by Wachsman.
As to the requirement that the solid-state electrolyte separator has a thickness of about 1 to 200 μm [or more narrowly between 10 and 100 μm as in claim 24], Roumi further teaches that the separator may have a thickness of 10 nm to 200 μm (paragraph [0077]), while Wachsman teaches that the garnet separator may have a thickness which is less than 100 μm, such as 5 to 30 μm or 10 to 20 μm (paragraph [0049]; Statement 47 of page 9). Therefore, the claimed thickness ranges are found to be obvious because the claimed thickness ranges lie within the broad range disclosed by Roumi, and the narrower ranges for garnet solid electrolyte separators substantially overlap or even lie within the claimed thickness ranges.
Regarding claim 4, the cited art remains as applied to claim 1. Roumi further teaches wherein the electrolyte separator may be a thin film or pellet separator (paragraph [0077]; alternatively, see “thin film battery” at paragraph [0060]; see also thin film or pellet type separators of Wachsman).
Regarding claim 20, the cited art remains as applied to claim 1. Roumi further teaches wherein the interlayer further comprises a constituent such as Au (Fig. 47; paragraph [0066]).
Regarding claim 21, the cited art remains as applied to claim 1. Roumi further teaches wherein the thickness of the interlayer may be 50 nm to 5 μm (paragraph [0070]). The requirement that the interlayer thickness is one of the values recited in claim is found to be obvious over the cited art at least because considered together, the limitations of claim 21 imply a range which overlaps the claimed range at least at about 3 to 5 μm.
Regarding claim 23, the cited art remains as applied to claim 1. The Fig. 47 embodiment is silent as to the material of the anode current collector.
However, Roumi does teach a different embodiment using a lithium metal electrode and a copper current collector wire (paragraph [0316]).
It would have been obvious to a person having ordinary skill in the art at the time of invention to utilize copper for the material of the current collector since Roumi generally teaches this feature, though in a separate embodiment from the Figure 7 embodiment.
Regarding claim 40, the cited art remains as applied to claim 1. Roumi further teaches wherein the device is formed by various technique with use of pressure being only one of a plurality of options (paragraph [0030, 0103]), and the normal operation of an electrochemical stack may be operation without additional pressure.
The claimed range of “lower than 300 psi” includes 0 psi, or at least positive values very close to 0 psi. Such values are implicitly taught by or at least obvious over the disclosure of Roumi which does not appear to teach a pressurized stack, with a non-pressurized stack being substantially the same as a stack pressurized at or close to 0 psi.
Regarding claim 42, the cited art remains as applied to claim 40. Roumi does not expressly teach wherein the electrochemical stack has an ASR at the surface of the separator of between 0.01 and 10 and [Symbol font/0x57]/cm2 at 10 ⁰C.
However, Roumi does teach that “the separator system provides a net ionic resistance from the positive electrode to the negative electrode selected over the range of 0.5 [Symbol font/0x57]/cm2 to 25 [Symbol font/0x57]/cm2, and preferably for some applications less than 5 [Symbol font/0x57]/cm2”, paragraph [0050]. See also Wachsman’s paragraph [0041] which teaches the solid electrolyte separator may be configured to reduce resistance to ion conductivity and interfacial resistance (paragraph [0041]).
It would have been obvious to a person having ordinary skill in the art at the time of invention to configure the electrochemical stack of Roumi to have an ASR at the surface of the separator of between 0.01 and 10 and [Symbol font/0x57]/cm2 at 10 ⁰C since the surface ASR would contribute to the overall resistance which should be made similarly small in view of the suggestion of Roumi and Wachsman and the resistance values of the separator system is a result-effective variable that influences the electrochemical efficiency of the stack.
Regarding claim 47-50, the cited art remains as applied to claim 1. Roumi further teaches wherein the interlayer is or comprises a metal such as nickel and/or aluminum hickness of the interlayer may be 50 nm to 5 μm (“conductive layer…Al… Ni, paragraph [0066]; see also the Ni mesh conductive layer of Fig. 47).
Claims 20 and 22 is/are rejected under 35 U.S.C. 103 as being obvious over the combination of Roumi (US 2013/0224632), Wachsman (US 2021/0083320) and Kajitani (US 2014/0079984) or Ryu (US 2017/0214093).
Regarding claim 20 and 22, the cited art remains as applied to claim 1. The cited art teaches the use of structure comprising a copper foil with interlayer comprising nickel, but does not explicitly teach wherein the interlayer comprises Ni and one of the named metals such as Au or decreases the contact angle of liquid lithium metal as claimed.
In the battery art, Katajini teaches that corrosion can be avoided by coating a copper current collector with nickel or with nickel and gold (paragraph [0077]).
In the battery art, Ryu teaches that a positive or negative current collector may be coated on the surface thereof with gold or silver for the benefit of increasing electron conductivity and reducing interfacial resistance (paragraphs [0069-0071]).
It would have been obvious to a person having ordinary skill in the art to further include Au in the interlayer for the benefit of protecting from corrosion, increasing conductivity and/or reducing interfacial resistance as taught by Katajini or Ryu.
Moreover, Applicant’s Figure 6 suggests that at least evaporated Au comprising interlayers are functional to reduce the contact angle; therefore, absent any evidence to the contrary, the provision of Au implicitly suggests an interlayer material which would be functional to decrease the contact area of liquid lithium.
Claim 42 and 52 is/are rejected under 35 U.S.C. 103 as being obvious over the combination of Roumi (US 2013/0224632), Wachsman (US 2021/0083320) and Cheng (US 2017/0214084).
Regarding claim 52, the cited art remains as applied to claim 1. The Roumi-Wachsman combined embodiment teaches an electrochemical stack comprising an LLZO garnet separator, but does not expressly teach wherein the LLZO includes Al2O3 as recited in the claim.
In the battery art, Cheng teaches that lithium stuffed garnet oxides are desirable materials for electrolytes having desirable safety qualities (paragraph [0003]). Cheng further teaches that the lithium stuffed garnet may have a formula such as LixLa3Zr2O12 y(Al2O3) wherein 3≤y≤8 and 0≤y≤1 (paragraph [0010]) such as wherein x=7 and y=1 (paragraph [0074, 0099]). Cheng further teaches that such solid electrolytes exhibit superior or desirable conductivity (paragraphs [0130-0131, 0161]).
It would have been obvious to a person having ordinary skill in the art at the time of invention to substitute the undoped LLZO of the Roumi-Wachsman combined embodiment with Li7La3Zr2O12 y(Al2O3) having the claimed x and y values as these materials are shown by Cheng to be particularly desirable solid electrolyte having superior properties such as high ionic conductivity.
Claim 42 has been previously rejected over the combination of Roumi and Wachsman; however, it is noted that the ionic conductivity of the separator is may be increased by Al2O3 doping as taught by Cheng. Thus, claim 42 is also rejected here for the reasons set forth in the previous rejection of claim 42, with the addition that the conductivity of the LLZO separator may be further increased, manipulated and optimized by Al2O3 doping as taught by Cheng.
Conclusion
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/JEREMIAH R SMITH/Primary Examiner, Art Unit 1723
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