Notice of Pre-AIA or AIA Status
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
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 12/30/2025 has been entered.
Status of Claims
Applicant’s amendment and arguments filed 12/30/2025 have been fully considered. Claim(s) 1 is/are amended; claim(s) 10-20 remain withdrawn; and claim(s) 4 has/have been canceled. Examiner affirms that the original disclosure provides adequate support for the amendment.
Upon considering said amendment and arguments, the previous rejection(s) under 35 U.S.C. 103 set forth in the Office action mailed 09/30/2025 has/have been withdrawn.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1-3, 5-9 are rejected under 35 U.S.C. 103 as being unpatentable over He et al. (US-20190393482-A1) in view of Chen et al. (CN-110144726-A; cited with machine translation, 05/14/2025 Office action) and Park et al. (KR-20200021187-A; cited with machine translation, 05/14/2025 Office action).
Regarding claims 1, 5, and 8, He is directed to a protective film for a lithium electrode (“anode”; “lithium […] as an anode active material”) (FIG. 2, [0014]) comprising a first layer (“first anode-protecting layer”) of a thin layer of lithium ion-conducting material in physical contact with the lithium electrode ([0014]; see (b)) and a second layer comprising an elastomer on the first layer ([0014]; see (c); FIG. 2), having the effect of preventing dendrite formation and ensuring uniform deposition of lithium with minimal interfacial resistance, thus improving cycle stability ([0092]).
While He’s disclosure reads on the general structure of a protective film for a lithium electrode comprising a first and second layer as claimed in claim 1, and indicates suitability of using a variety of Li-ion conducting polymers for the first protective layer ([0020]; exemplified in [0167]), He fails to further specify a first layer “comprising polyvinyl alcohol (PVA) and polyacrylic acid (PAA), wherein the first layer is porous” as claimed in claim 1.
Chen is directed to a polyvinyl alcohol/polyacrylic acid fiber material having a surface treated with lithium for use in a lithium-sulfur battery membrane (Chen [0007], [0052]). Similarly, the membrane comprising the PVA/Li-PAA fiber material protects a lithium metal electrode and addresses analogous needs of ensuring continuous Li ion deposition and dendrite prevention ([0004]), where the PVA/Li-PAA material provides significantly improved ion Li ion conductivity ([0055]).
Thus, in seeking to provide a sufficiently provide or improve the Li ion conductivity in He’s first layer, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to select Chen’s PVA/Li-PAA fiber material to form He’s first layer. Such a selection would be made with a reasonable expectation of success; He requires the first layer to be a thin layer of material having a sufficiently high degree of lithium ion conductivity in physical contact and protecting the lithium electrode (He [0014]); Chen’s material is indicated as having enhanced lithium-ion conductivity (Chen [0037] and is similarly envisioned for use in protecting a lithium metal electrode ([0004-0005]) (MPEP 2144.07).
Chen’s PVA/Li-PAA fiber material is formed by treating PVA/PAA fibers with LiOH to convert polyacrylic acid on the fiber surface to lithium polyacrylate ([0054]); it would be apparent to one of ordinary skill in the art that some amount of PAA underneath the fiber surface would not be converted to Li-PAA. Additionally, the PVA/PAA fiber material comprises about 65–75% porosity ([0031]). Thus, a skilled artisan performing the above modification of He’s protective film to form a first layer out of the PVA/Li-PAA fiber material taught by Chen would form “a first layer comprising polyvinyl alcohol (PVA) and polyacrylic acid (PAA), wherein the first layer is porous” as claimed in claim 1. The range of 65–75% porosity is additionally within the scope of the claimed “protective film of claim 1, wherein the first layer has a porosity of 50% to 98%” of claim 5, being within and thus rendering obvious the claimed range.
He further discloses an example embodiment of a second layer comprising sulfonated styrene-butadiene-styrene block copolymer disposed on a first layer (He Example 12, [0162-0164]), thus disclosing with sufficient specificity the inclusion of a second layer comprising sulfonated SBS block copolymer on the first layer. He indicates the sulfonation process results in a substitution in a portion of the polymer units (e.g., 13 to 82 mol % of the styrene in poly(styrene-isobutylene-styrene), [0120]); thus, modified He’s protective film comprising a second layer of sulfonated SBS necessarily comprises “a styrene-butadiene-styrene block copolymer, wherein the second layer is disposed on the first layer” reading on the scope of claim 1, the SBS copolymer being the remaining unreacted SBS copolymer.
Furthermore, while He suggests modifications to the second protective layer to improve the ion conductivity, such as using additives or fillers ([0107-0108]), He fails to expressly disclose a porosity of the second layer for this purpose.
Park (KR-20200021187-A), directed to a highly stretchable polymer protective layer for a lithium electrode (He [0001]) analogous to He’s elastic second layer, teaches forming pores in the highly stretchable polymer protective layer in order to improve the lithium-ion conductivity ([0020]). When the porosity is at least 50%, the lithium-ion conductivity is improved, and when less than 90%, the highly stretchable polymer protective layer suitably prevents the effects of lithium dendrites ([0020]).
Therefore, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to form pores in modified He’s second protective layer in order to improve the Li-ion conductivity as taught by Park, thus forming a porous second layer as claimed in claim 1. It would likewise be obvious to utilize the second layer porosity of 50% to 90% claimed in claim 8 in order to sufficiently improve the Li-ion conductivity while preventing dendrites as taught by Park. Such modifications would be made with a reasonable expectation of success, as Park’s protective layer remains stretchable, i.e., elastic (Park [0010]) as required in He’s second layer, and because He envisions a general suitability of modifying the second layer to improve the ion conductivity (He [0023], [0107-0108]).
Modified He further discloses the first layer has a thickness of 1 nm to 100 µm (He [0014]), this range encompassing the claimed “wherein the first layer has a thickness of 1 µm to 20 µm” of claim 1 such that a skilled artisan seeking to form modified He’s first layer to achieve the effects of dendrite prevention uniform Li deposition, and improved cycle life would routinely have selected within the overlap with a reasonable expectation of successfully forming the first layer of modified He’s protective film (MPEP 2144.05 I).
Furthermore, it would be apparent to one of ordinary skill in the art that at least some minimum thickness of first layer is necessary to provide the desired effects of the protective film; He ¶ [0161] and [0164-0165] indicate reductions in cycle life from protective films lacking the first layer (e.g., with 0 µm thickness; see line “LiCoO2 cathode[…]” compared with “Double layer […]” in FIG. 4). At the same time, He desires to avoid unnecessary weight and volume to maximize the energy density of the battery ([0011-0013]); given that lithium is stored in only the electrodes ([0096]), it would be reasonably apparent to one of ordinary skill in the art that an unnecessarily large (e.g., 100 µm thick) first layer which does not itself store lithium would undesirably detract from the battery energy density.
Thus, in seeking to balance providing sufficient effects of the first layer to improve the cycle life without detracting from the energy density, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to optimize a thickness of modified He’s first layer between a range of 1 nm to 100 µm, encompassing “the first layer has a thickness of 1 µm to 20 µm” of claim 1 such that a skilled artisan would have selected within the overlap through routine optimization under He’s disclosure with a reasonable expectation of success (MPEP 2144.05 II).
Regarding claim 2, modified He discloses the protective film of claim 1. While He fails to disclose the ratio of PVA to PAA in the first layer, Chen teaches example embodiments of the PVA/Li-PAA material of the first layer formed with raw materials of 5 PVA:7.5 PAA (Chen Example 1, [0049]) and 4 PVA:8.5 PAA (Example 2 [0058]), i.e., 1:1.5 and 1:2.125 respectively. A portion of PAA on the first layer fiber surface is consumed to form Li-PAA and improve Li-ion conductivity ([0054]), thus the ratio of PVA:PAA is reduced below 1:2.125. On the other hand, performing the lithium treatment on surficial PAA reduces the porosity to some degree ([0056]), which may be undesirable if reacted to excess to reduce the porosity outside the preferred range of 65-75% ([0031]); thus, some minimum preferable ratio of PVA:PAA above at least 1:0 is implicit in Chen’s teaching.
Therefore, in seeking to balance considerations of improving Li-ion conductivity and providing sufficient porosity in modified He’s first layer, it would be obvious for one having ordinary skill in the art to optimize the amount of PAA reacted into Li-PAA in the PVA/Li-PAA material used in the first layer taught by Chen. In the above optimization, a skilled artisan would necessarily optimize a ratio of PVA:PAA between 1:2.125 to 1:0, overlapping with a portion of the claimed “the first layer comprises the PVA and the PAA at a mass ratio of 1:3 to 3:1” in claim 2 between 1:2.125 to 3:1 such that a skilled artisan would utilize at least a portion of the overlapping range through routine optimization (MPEP 2144.05 II).
Regarding claim 3, modified He discloses the protective film of claim 1. While He fails to expressly disclose the use of electrospinning to form the first layer as claimed, Chen discloses a method of forming the first layer material by accumulating nanofibers in which a spinning solution comprising the PVA and the PAA is electrospun as claimed in claim 3 (Chen [0011]). Thus, it would be obvious for one having ordinary skill in the art to select this method taught by Chen to form the first layer of He modified in view of Chen (MPEP 2144.07), resulting in the claimed “the first layer has a structure formed by accumulating nanofibers in which a spinning solution comprising the PVA and the PAA is electrospun” of claim 3.
Regarding claim 6, modified He discloses the protective film of claim 1, but fails to expressly disclose “the second layer has a structure formed by accumulating nanofibers in which a spinning solution comprising a styrene- butadiene-styrene block copolymer is electrospun” as claimed in claim 6.
As a suitable method of forming the porous SBS second layer with the desired porosity, Park teaches electrospinning an SBS polymer solution (Park [0020], [0050]). As such, in seeking to form the second layer of He modified in view of Park with a suitable porosity, it would be obvious for one having ordinary skill in the art to use electrospinning, which would result in the claimed “second layer has a structure formed by accumulating nanofibers in which a spinning solution comprising a styrene- butadiene-styrene block copolymer is electrospun” of claim 6 (MPEP 2144.07).
Such a selection would be made with a reasonable expectation of success, as He’s disclosure indicates that the sulfonated SBS used to form the first layer may be suitably dissolved in toluene during synthesis (He [0151]), and would therefore be capable of dissolution in a spinning solution used by Park’s electrospinning method.
Regarding claim 7, modified He discloses the protective film of claim 1. He discloses experimental examples of second layers formed of elastomer materials with thicknesses of 1-2µm (pp. 17 Table 1; [0168]), thus rendering obvious or disclosing with sufficient specificity the selection of a second layer having a thickness of 1-2 µm which falls within the claimed “the second layer has a thickness of 1-20 µm” in claim 7.
Furthermore, He further discloses a preferable thickness of the second layer as being 10 nm to 20 µm (He [0089]), where excessively thick films interfere with Li ion conductivity (He [0089], [0168]). Additionally, Park notes that an insufficiently thick polymer protective layer (i.e., the second layer) cannot protect against lithium dendrites (Park [0021]); He similarly envisions that the protective film (“anode-protecting layers”) acts to block penetration of the dendrite ([0062]) such that a skilled artisan would consider increasing the second layer thickness to block dendrites.
As such, in seeking to sufficiently block dendrite formation with He’s protective film without interfering with Li ion conductivity, it would be obvious for one having ordinary skill in the art to optimize a second layer thickness within a range of 10nm-20µm according to He and Park’s disclosure, this range closely encompassing the claimed “the second layer has a thickness of 1-20 µm” of claim 7 such that a such that a skilled artisan would have selected within the overlap through routine optimization with a reasonable expectation of success (MPEP 2144.05 II).
Regarding claim 9, modified He discloses a lithium electrode for a lithium secondary battery, comprising: a plate-shaped lithium metal (“thin Li foil or LI coating”); and the protective film (“two anode-protecting layers”) of claim 1 disposed on the lithium metal (He [0094]), wherein the first layer of the protective film is disposed on the lithium metal ([0072]; FIG. 2).
Response to Arguments
Applicant’s arguments filed 12/30/2025 with respect to rejection of claim 1 under 35 U.S.C. 103 over He et al. (US-20190393485-A1) in view of Chen (CN-110144726-A) and Park (KR-20200021187-A) (see Remarks pp. 5-9) have been considered but are moot because the new ground of rejection made in view of He (US-20190393482-A1) in view of Chen and Park under 35 U.S.C. 103 as presented above does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Applicant has amended claim 1 to incorporate subject matter of dependent claim 4 to recite “the first layer has a thickness of 1 µm to 20 µm”. Applicant asserts that the range of 1 nm to 100 µm disclosed by He (US-20190393485-A1) as relied upon in the 09/30/2026 Office action is relatively broad, and thus fails to suggest the relatively narrow range of amended claim 1 as required under MPEP 2131.03 (II) for purposes of anticipation (Remarks pp. 8).
He (US-20190393485-A1) is no longer relied upon as prior art of record, but He (US-20190393482-A1) as cited in this Office action discloses an identical range of 1 nm to 100 µm (He [0014]) such that arguments filed in pp. 8 of Remarks are still applicable in view of newly cited prior art.
While considered, said remarks have not been found persuasive, as the prior art range of 1 nm to 100 µm is not relied upon for anticipation of the claimed range under 35 U.S.C. 102, but for obviousness under 35 U.S.C. 103; see MPEP 2131.03 (III). Additionally, Applicant’s remarks and experimental results do not appear to demonstrate criticality of the narrower claimed first layer thickness range over the comparatively broad prior art thickness range; Applicant’s examples and comparative examples only compare an embodiment with a 20 µm thick first layer (Example, inst. spec. pp. 19) and an embodiment without any first layer (Comparative Example 2, pp. 20) and thus fail to rebut the finding of obviousness of the broader encompassing range (MPEP 2144.05 III).
Applicant asserts unexpected results of low ionic resistance while also maintaining structural stability of the second layer within the claimed thickness range (Remarks pp. 8-9, inst. spec. pp. 15).
While this argument has been fully considered, it has not been found persuasive as the prior art teaches or discloses the cited effects of ionic resistance and structural stability arising from the second layer thickness; see discussion of claim 7 above; (MPEP 716.02(c) II).
Conclusion
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/E.C./Examiner, Art Unit 1751
/JONATHAN G LEONG/Supervisory Patent Examiner, Art Unit 1751 5/21/2026
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