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 .
Claim Objections
Claims 1 and 3 are objected to for minor grammatical errors, reciting “improving an interface of composite solid electrolyte” in the preamble; it is suggested that this be corrected to “improving an interface of a composite solid electrolyte”.
Claim 5 is objected to for a minor grammatical error, reciting “fully stirring und mixing”.
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.
Claims 1 and 2 are rejected under 35 U.S.C. 103 as being unpatentable over Guo et al. CN-110581303-A (cited in CN office action filed 08/27/2024, see attached machine translation) in view of Li et al. CN-112002951-A (see attached machine translation)
Regarding claims 1 and 2, Guo discloses a method for improving an interface of a solid electrolyte in situ (Guo [0046]) using an interface layer comprising a succinonitrile plastic crystal material and a lithium salt which is melted and then solidified ([0080-0084]). While Guo does not explicitly describe the succinonitrile plastic crystal as being a trans-gauche isomeric plastic crystal, the instant specification identifies succinonitrile as a trans-gauche isomeric plastic crystal (Instant specification, [0006]). As such, Guo’s interface layers are broadly and reasonably interpreted as trans-crystalline solidified liquids as claimed.
Guo further discloses the method for improving an interface of a solid electrolyte in situ, comprising constructing a first trans-gauche isomeric plastic crystal layer (“plastic crystal interlayer”) between a positive electrode and a solid electrolyte by cooling and solidifying a first trans-crystalline solidified liquid and constructing a second trans-gauche isomeric plastic crystal layer between the solid electrolyte and a negative electrolyte by cooling and solidifying a second trans-crystalline solidified liquid ([0091], [0116], FIG. 4).
Guo’s solid electrolyte layer comprises an ion-conducting ceramic material ([0102]), with garnet solid electrolyte, perovskite solid electrolyte, and NASICON solid electrolyte as non-limiting examples of the material ([0102-0103]), and Guo’s plastic crystal layers are provided as an interface between the solid electrolyte and electrodes to improve the improve the ionic conductivity, electrochemical window and cycle stability ([0070-0071]). While Guo does not necessarily exclude the selection of a composite solid electrolyte with the method, i.e., an electrolyte comprising the ion-conducting ceramic material and further comprising a polymer, Guo only positively discloses the ion-conducting ceramic material as a component of the solid electrolyte ([0027]) and does not explicitly disclose an additional polymer component.
Li is directed to an analogous method of improving an interface of a solid electrolyte by applying a trans-crystalline solidified liquid (“interfacial wetting agent”) comprising succinonitrile and a lithium salt to an interface between the electrodes and solid electrolyte layer to form trans-gauche isomeric plastic crystal layers (“interface modification layer”) (Li [0013], [0071]), thus improving the ionic conductivity, electrochemical window, and stability and cycling characteristics ([0022]). Additionally, Li shares a need to avoid the use of a liquid electrolyte in the composite solid electrolyte to prevent the risk of fire and explosion ([0004]). Li teaches the method as suitable for use with a solid electrolyte layer (“oxide electrolyte”) comprising garnet, perovskite, or NASICON solid electrolyte as disclosed by Guo, and further teaches this type of solid electrolyte layer as being a substitutable equivalent to a composite solid electrolyte obtained by combining the aforementioned solid electrolyte materials with a polymer (Li [0057]).
Therefore, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to substitute the solid electrolyte layer of Guo’s method with a composite solid electrolyte layer as taught by Li, thus providing a method of improving an interface of a composite solid electrolyte in situ comprising constructing a first and second trans-gauche isomeric plastic crystal layer between a positive electrode and the composite solid electrolyte and a negative electrode and the composite solid electrolyte respectively, by cooling and solidifying a first and second trans-crystalline solidified liquid as claimed. Such a substitution would be made with a reasonable expectation of success as Li recognizes both electrolyte layers as substitutable equivalents for use with a method to improve the ionic conductivity, electrochemical window, and stability and cycling characteristics of an interface by providing a trans-crystalline solidified liquid in the interface (MPEP 2144.06 II), and because both the solid-state electrolyte and composite solid electrolyte comprise the ion conducting ceramic material and avoid a liquid electrolyte to prevent fire and explosion.
As a mixture for the first and second trans-crystalline solidified liquid, Guo discloses an experimental example prepared by mixing 4 mol% LiTFSI as the lithium salt into succinonitrile as the trans-gauche isomeric plastic crystal ([0122]), equivalent to a mixing ratio of 87.0 wt% succinonitrile plastic crystal and 13 wt% LiTFSI salt which falls within the claimed range of 82-91% plastic crystal and 9-18 wt% lithium salt in the first trans-crystalline solidified liquid and 82-91% plastic crystal and 8-17 wt% lithium salt in the second trans-crystalline solidified liquid. Guo discloses that the trans-crystalline solidified liquid further comprises 2.5-5 volume% of a fluoroethylene carbonate additive ([0025-0026]), the additive volume being balanced according to considerations of providing enough additive to improve the coulombic efficiency of the battery ([0132]) without impairing the ability of the trans-crystalline solidified liquid to solidify at room temperature ([0124]). In seeking to balance these considerations, it would therefore be obvious to optimize a volume percentage of the additive within a range of 2.5-5 vol%; additionally, as the instant claim reciting “0.01-3% of additives” does not limit the percentage to a weight percentage specifically, this range of 2.5-5 vol% additive is broadly and reasonably interpreted as reading on the claimed range of 2.5-3% of additives in the second trans-crystalline solidified liquid (MPEP 2144.05 II).
While providing the additive would decrease the relative weight percentages of the plastic crystal and lithium salt mixed to form the first and second trans-crystalline solidified liquid, given the minute quantities of additive (2.5-3 vol%) provided in the mixture relative to the amount of lithium salt and plastic crystal (97-98.5 vol%), one having ordinary skill in the art would still expect the weight percentages of plastic crystal (87.0 wt%) and lithium salt (13 wt%) to remain within the claimed ranges of 82-91% plastic crystal and 8-17 wt% lithium salt in the first trans-crystalline solidified liquid and 82-91% plastic crystal and 8-17 wt% lithium salt in the second first trans-crystalline solidified liquid as claimed.
In a working embodiment of the method, Guo discloses (claim 1) the trans-gauche isomeric plastic crystals as succinonitrile, the additive as fluoroethylene carbonate, and (claim 2) the lithium salt as lithium bis-trifluoromethane sulfonyl imide (“LiTFSI”) ([0122]).
Claims 3, 4, 7, and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Guo CN-110581303-A in view of Li CN-112002951-A, NPL Despatch Industrial Oven “PCC2-15 Conveyor Oven for Battery Bonding” (see copy provided with this office action) Wu et al. CN-112531204-A (see attached machine translation), and as evidenced by Ryu et al. US-20220085351-A1
Regarding claim 3, Guo discloses a method for improving an interface of a solid electrolyte in situ (Guo [0046]) using an interface layer comprising a succinonitrile plastic crystal material and a lithium salt which is melted and then solidified ([0080-0084]). While Guo does not explicitly describe the succinonitrile plastic crystal as being a trans-gauche isomeric plastic crystal, the instant specification identifies succinonitrile as a trans-gauche isomeric plastic crystal (Instant specification, [0006]). As such, Guo’s interface layers are broadly and reasonably interpreted as trans-crystalline solidified liquids as claimed.
A preferred embodiment of a battery in Guo’s method comprises a first and second interlayer formed with a trans-crystalline solidified liquid interface between the positive electrode and solid electrolyte and between the solid electrolyte and negative electrode respectively ([0116], FIG. 4); the trans-crystalline solidified liquid used to form the first interlayer is broadly and reasonably interpreted as the first trans-crystalline solidified liquid and the liquid used to form the second interlayer is similarly interpreted as the second trans-crystalline solidified liquid.
As a step S1 of forming a mixture for the first and second trans-crystalline solidified liquid ([0084]), Guo discloses an experimental example prepared by mixing 4 mol% LiTFSI as the lithium salt into succinonitrile as the trans-gauche isomeric plastic crystal ([0122]), equivalent to a mixing ratio of 87.0 wt% plastic crystal and 13 wt% LiTFSI salt which falls within the claimed range of 82-91% plastic crystal and 9-18 wt% lithium salt in the first solidified liquid and 82-91% plastic crystal and 8-17 wt% lithium salt in the second solidified liquid. Guo discloses that the mixture further compresses 2.5-5 volume% of a fluoroethylene carbonate additive ([0025-0026]), the additive volume balanced to improve coulombic efficiency ([0132]) without impairing the ability of the trans-crystalline solidified liquid to solidify at room temperature ([0124]). In seeking to balance these considerations, it would therefore be obvious to optimize a volume percentage of the additive within a range of 2.5-5 vol%; additionally, instant claim reciting “0.01-3% of additives” does not limit the percentage to a weight percentage specifically, this range of 2.5-5 vol% additive is therefore broadly and reasonably interpreted as reading on the claimed range of 2.5-3% of additives in the second trans-crystalline solidified liquid (MPEP 2144.05 II).
While providing the additive would decrease the relative weight percentages of the plastic crystal and lithium salt mixed to form the first and second trans-crystalline solidified liquid, given the minute quantities of additive (2.5-3 vol%) provided in the mixture relative to the amount of lithium salt and plastic crystal (97-98.5 vol%), one having ordinary skill in the art would still expect the weight percentages of plastic crystal (87.0 wt%) and lithium salt (13 wt%) to remain within the claimed ranges of 82-91% plastic crystal and 8-17 wt% lithium salt in the first trans-crystalline solidified liquid and 82-91% plastic crystal and 8-17 wt% lithium salt in the second first trans-crystalline solidified liquid as claimed.
Guo further discloses a step of heating and melting at 70 °C ([0081], [0122]), fully stirring and mixing and then cooling to room temperature to obtain the first and second trans-crystalline solidified liquid ([0081]).
Guo discloses a step S2 of providing, i.e., preparing, a solid electrolyte layer ([0083], [0090]) comprising an ion-conducting ceramic material ([0102]), with garnet, perovskite, and NASICON solid electrolyte as non-limiting examples of the material ([0102-0103]), wherein no liquid electrolyte is included in the solid electrolyte in order to prevent the risk of fire and explosion ([0004]). In Guo’s method, the plastic crystal layers are provided an interface between the solid electrolyte and electrodes to improve the improve the ionic conductivity, electrochemical window and cycle stability ([0070-0071]). While Guo does not necessarily exclude the selection of a composite solid electrolyte with the method, i.e., an electrolyte comprising the ion-conducting ceramic material and further comprising a polymer, Guo only positively discloses the ion-conducting ceramic material as a component of the solid electrolyte ([0027]) and does not explicitly disclose an additional polymer component.
Li is directed to an analogous method of improving an interface of a solid electrolyte by applying a trans-crystalline solidified liquid (“interfacial wetting agent”) comprising succinonitrile and a lithium salt to an interface between the electrodes and solid electrolyte layer to form trans-gauche isomeric plastic crystal layers (“interface modification layer”) (Li [0013], [0071]), thus improving the ionic conductivity, electrochemical window, and stability and cycling characteristics ([0022]). Li addresses similar considerations of avoiding liquid electrolytes to prevent fire and explosion in the method ([0002-0004]). Li teaches the method as suitable for use with a solid electrolyte layer (“oxide electrolyte”) comprising garnet, perovskite, or NASICON solid electrolyte as disclosed by Guo, and further teaches this type of solid electrolyte layer as being a substitutable equivalent to a composite solid electrolyte obtained by combining the aforementioned solid electrolyte materials with a polymer (Li [0057]).
Therefore, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to substitute the solid electrolyte layer of Guo’s method with a composite solid electrolyte layer as taught by Li, thus providing a method of improving an interface of a composite solid electrolyte in situ and a step S2 of preparing the composite solid electrolyte. Such a substitution would be made with a reasonable expectation of success as Li recognizes both electrolyte layers as substitutable equivalents for use with a method to improve the ionic conductivity, electrochemical window, and stability and cycling characteristics of an interface by providing a trans-crystalline solidified liquid in the interface (MPEP 2144.06 II), because both the solid-state electrolyte and composite solid electrolyte comprise the garnet, perovskite, or NASICON solid electrolyte material required by Guo, and because Li’s composite solid electrolyte similarly avoids the use of a liquid electrolyte to prevent fire and explosion.
Guo discloses a step S4 of heating the first trans-crystalline solidified liquid obtained in the S1 to 70 °C ([0087], [0129]) and drop-casting, i.e, dripping, the first trans-crystalline solidified liquid into the positive electrode prepared in the S3 ([0090]). In an example embodiment, Guo drips 5 µL of a trans-crystalline solidified liquid to form a trans-gauche isomeric plastic crystal layer in a battery having a diameter of 12mm, an equivalent an area being 1.131 cm2 ([0090], [0129]) and corresponding to a dripping amount of 4.42 µL/cm2 which falls within the claimed range of 3-15 µL.
While Guo does not explicitly disclose a step of cooling to the room temperature and solidifying to form the first trans-gauche isomeric plastic crystal layer after dripping the trans-crystalline solidified liquid onto the positive electrode, Ryu, directed to an analogous method of dripping succinonitrile onto an electrode surface to form an interface (Ryu [0030], [0043]) evidences that liquid succinonitrile dripped in this manner is quickly cooled to room temperature into a solid wax within a few seconds ([0041-0043]). Guo’s first trans-crystalline solidified liquid comprises mostly (~87 wt%) succinonitrile (Guo [0122]) and would behave similar to the melted succinonitrile in Ryu’s method; as Guo does not disclose any procedures to maintain the first trans-crystalline solidified liquid in a melted state after being dripped (Guo [0036-0039], [0082-0091]), one having ordinary skill in the art would expect the dripped first trans-crystalline solidified liquid to be inherently cooled to the room temperature and solidified to form a first trans-gauche isomeric plastic crystal layer after dripping (MPEP 2112 III).
Modified Guo discloses a step of assembling the electrodes having the interlayer (e.g., the positive electrode having the first trans-gauche isomeric plastic crystal layer) and the solid electrolyte (Guo [0091]); as the first trans-gauche isomeric plastic crystal layer is located between the positive electrode and the composite solid electrolyte ([0116], FIG. 4), the composite solid electrolyte prepared in the S2 would need to be provided covering the first trans-gauche isomeric plastic crystal layer as claimed.
Modified Guo discloses a step S5 of heating the second trans-crystalline solidified liquid obtained in the S1 to 70 °C ([0087], [0129]) and drop-casting, i.e, dripping the second trans-crystalline solidified liquid into the composite solid electrolyte in the S4 ([0090]). In an example embodiment, Guo drips 4.42 µL/cm2 of a trans-crystalline solidified liquid ([0090], [0129]) which falls within the claimed range of 3-15 µL.
While modified Guo does not explicitly disclose a step of cooling to the room temperature and solidifying to form the second trans-gauche isomeric plastic crystal layer, one having ordinary skill in the art would reasonably expect the second trans-crystalline solidified liquid dripped in the same manner as the first trans-crystalline solidified liquid to be quickly cooled to room temperature into a solid wax within a few seconds as evidenced by Ryu ([0041-0043]), inherently cooling to the room temperature and solidifying to form a second trans-gauche isomeric plastic crystal layer (MPEP 2112 III).
During the assembly step (Guo [0091]), as the second trans-gauche isomeric plastic crystal layer is located between the negative electrode and the composite solid electrolyte ([0116], FIG. 4), the negative electrode prepared in the S2 would similarly need to be provided covering the second trans-gauche isomeric plastic crystal layer, as there is no other suitable location to place the negative electrode such that the second trans-gauche isomeric plastic crystal layer is disposed between the negative electrode and the composite solid electrolyte (MPEP 2112 III).
In an experimental example, Guo discloses a step of sealing, i.e., encapsulating a battery in a Swagelok-type test cell after assembling the electrodes, an isomeric plastic crystal layer, and a solid electrolyte layer ([0137]).
While Guo desires to improve interfacial contact and ion transport between the electrodes and the electrolyte layer ([0091]) and improve the electrochemical stability of the battery ([0131]), Guo’s method does not further provide a step of placing the battery in an oven at 50-100° C. for 5-20 min, and then taking the battery out and cooling the battery to the room temperature and solidifying to obtain the composite solid-state battery with an improved interface.
Li, directed to an analogous method of improving a battery comprising a structure of a first and second trans-gauche isomeric plastic crystal layer (“interface modification layer”) provided between the electrodes and solid electrolyte layers to improve the ionic conductivity, electrochemical window, and stability and cycling characteristics (Li [0021-0022]), Li’s plastic crystal layers likewise comprising succinonitrile, a lithium salt, and an additive ([0071]), teaches that a method of improving an interface having this composition is further improved through a step of thermal and treatment after assembly wherein the interfacial wetting agent is melted at a high temperature before being cooled and solidified, advantageously improving the strength and stability of the trans-gauche isomeric plastic crystal layers and improving the reaction and contact impedance ([0033]).
As Li demonstrates a suitability of this step in a method for a battery having substantially similar materials and construction as Guo’s battery, one having ordinary skill in art would seek to improve Guo’s method through further providing a step of heat treatment before cooling and solidifying the battery at room temperature after the step of battery assembly as taught by Li, with a predictable result of improving the interface strength and stability and decreasing the impedance of the interface, these effects being recognized as improvements by Guo (MPEP 2143 I. D.).
While not specified by Guo, Li indicates that the heat treatment temperature should be at least 35 °C to sufficiently melt the plastic crystalline compound of the trans-gauche isomeric plastic crystal layers, while less than 90 °C in order to maintain thermal stability of the lithium salt (Li [0066]); as such, in seeking to balance these considerations, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to optimize a temperature of the heat treatment of S6 within a temperature of 35 °C to 90 °C, which overlaps with a portion of the claimed range between 50-90 °C (MPEP 2144.05 II).
Furthermore, while Guo and Li do not specify a particular type of equipment to perform the treatment as being an oven, Despatch Industrial Oven teaches a suitability of a conveyor oven for providing heat treatment to bond battery components (Despatch Industrial Oven, pp. 1); modified Guo’s heat treatment is provided for the similar purpose of strengthening the interface connection between the electrodes and solid electrolyte, i.e., bonding these components (Li [0033]). Despatch Industrial Oven also teaches that an oven allows for tight temperature control of the heat treatment process (Despatch Industrial Oven, pp. 1); modified Guo similarly requires a controlled temperature to melt the plastic crystal layers while maintaining thermal stability of the lithium salt (Li [0066]). As such, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to select a step of placing the battery in an oven to perform this heat treatment with a reasonable expectation of success, as Despatch teaches suitability of an oven for performing heat treatment to strengthen an interface connection and for maintaining a controlled temperature the heat treatment process (MPEP 2144.07).
Guo and Li do not explicitly disclose a duration of the step S6 heat treatment; however, Wu, directed to a method of heat-treating a composite solid electrolyte comprising a plastic crystal material (Wu [n0005-n0006]), notes that a heat-treatment step which results in melting a plastic crystal electrolyte material is suitably performed for a duration of 0.1h (i.e., 6 minutes) to 12h ([n0039]). While Wu’s heat-treatment process is performed for a different overall method of improving a composite solid electrolyte ([n0005-n0009]), both Wu and modified Guo similarly require that the plastic crystal material be melted during the heat-treatment process (Li [0066], Wu [n0039]).
As such, in seeking to ensure suitable melting of the plastic crystal material in Guo’s trans-gauche isomeric plastic crystal layers during Li’s heat treatment, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to perform Li’s heat treatment for a duration between 6 minutes to 12 hours as taught by Wu, with a reasonable expectation of success as Wu teaches that this duration is suitable to melt the plastic crystal material as required for Li’s heat treatment procedure (MPEP 2144.07); the duration taught by Wu overlapping with a portion of the claimed range between 6-20 min (MPEP 2144.05 I).
Subsequently, modified Guo discloses that the battery is cooled to room temperature and solidified to obtain a composite solid-state battery with an improved interface (Li [0065]).
Regarding claim 4, modified Guo discloses for improving the interface of the composite solid electrolyte in situ according to claim 3, wherein the trans-gauche isomeric plastic crystals are succinonitrile (Guo [0021]), the additives are fluoroethylene carbonate ([0025]), and the lithium salt is one or more of lithium bis-trifluoromethane sulfonyl imide, lithium perchlorate, lithium bis-oxalate borate, lithium hexafluorophosphate and lithium tetrafluoroborate ([0024]).
Regarding claim 7, modified Guo discloses the method for improving the interface of the composite solid electrolyte in situ according to claim 3. Guo further discloses a working embodiment of the method wherein in the S3, the positive electrode is obtained by mixing 80% positive active materials (“LiFePO4”), 10% conductive agent (“conductive carbon black”), and 100% polymer binder (“PVDF binder”) (Guo [0126]), wherein the active material is LiFePO4, the conductive agent is conductive carbon black, and the polymer binder is polyvinylidene fluoride (Guo [0126]).
Regarding claim 8, modified Guo discloses the method for improving the interface of the composite solid electrolyte in situ according to claim 3, wherein a working embodiment of the negative electrode in the S5 is produced with metal lithium (Guo [0127]).
Claims 5 and 6 are rejected under 35 U.S.C. 103 as being unpatentable over Guo in view of Li and Wu, and evidenced by Ryu as applied to claim 3, further in view of Kim et al. KR-20140127114-A (see attached machine translation), NPL Liu et al. “Synergistic Effect of Lithium Salts with Fillers and Solvents in Composite Electrolytes […]” (see copy provided with this office action), and NPL R2R Processing “Roll to Roll (R2R) Processing Technology Assessment” (copy of pp. 7-11 provided with this office action)
Regarding claim 5, modified Guo discloses the method for improving the interface of the composite solid electrolyte in situ according to claim 3. While Guo does not explicitly disclose a method of preparing the composite solid electrolyte, Li, relied upon to teach substitution of Guo’s solid-state electrolyte with an equivalent composite solid electrolyte (Li [0026-0027]), teaches that the composite solid electrolyte in the S2 is suitably prepared through mixing the polymer, salt, and inorganic ceramic according to to a mass ratio of 68 wt%: 22 wt%: 10 wt%, equivalent to 1:0.32:0.15 (Li [0075]).
While Li’s mixture of organic polymer, lithium salt and inorganic ceramic in a ratio of 1:0.32:0.15 approaches the claimed range of 1:(0.5-1):(0.15-1) and would be reasonably expected to share similar properties, Guo in view of Li does not explicitly indicate a range of composite solid electrolyte compositions including a lithium salt in the range of 0.5-1 parts to 1 part of the organic polymer.
Liu, directed to considerations of composite solid electrolytes (Liu, abstract), indicates that increasing a concentration of lithium salt relative to organic polymer in the composite solid electrolyte above a ratio of 0.5 parts salt to 1 part polymer decreases the crystallinity of the composite solid electrolyte and increases the amount of lithium-ion carrier concentration, improving conduction speed of lithium ions (pp. 2486 col. 1 paragraph 1, pp. 2487 col. 1 paragraph 2-col. 2 paragraph 1, FIG. 1d), while excessive addition of salt beyond a ratio of 1.25 parts salt to 1 part polymer impairs mechanical properties without improving ionic conductivity (pp. 2486 col. 1 paragraph 1). Guo envisions similar considerations regarding the plastic crystal layer, noting that providing lithium salt in the plastic crystal layer improves the ion conductivity between layers ([0070-0071]), while demonstrating that too large a proportion of salt and additives impairs mechanical properties of the plastic crystal layer (Guo [0092], [0124]).
As such, in seeking to balance improving the lithium-ion conductivity of modified Guo’s composite solid electrolyte without impairing the mechanical properties, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to utilize a step of mixing organic polymer, lithium salt, and inorganic ceramic in a range of 1:0.5-1.25:0.15 as taught by Liu; overlapping with a portion of the claimed range between 1:0.5-1:0.15 (MPEP 2144.05 II). Such an optimization would be made with a reasonable expectation of success as Guo envisions optimizing with respect to these considerations in other components of the battery of the method, and would envision similar considerations as applied to the composite solid electrolyte layer.
While Guo in view of Li discloses a suitability of preparing a composite solid electrolyte with the method (Li [0057], [0073]), and Guo requires that the battery of the method does not contain an electrolyte in a liquid state ([0002]), modified Guo does not explicitly specify details of preparing the composite solid electrolyte as including dissolving the mixed powder in a solvent with 5-8 times mass of the mixed powder, fully stirring and mixing, and coating on a glass plate or a PTFE plate by a tape casting method, and drying at 40-100° C.
Kim, directed to a method of preparing a composite solid electrolyte comprising a blend of polymers, a lithium salt, and an inorganic ceramic (“inorganic filler”) which does not require an electrolyte in a liquid state (Kim [0002-0014]), teaches a procedure of preparing the composite solid electrolyte by dissolving the mixed powder ingredients in a solvent and fully stirring and mixing ([0021-0022]), coating on a PTFE (“Teflon”) plate to a constant thickness through a method known in the art ([0023]) before drying at 60 °C to obtain a composite solid electrolyte membrane ([0029]).
As such, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to select the procedure taught by Kim to prepare modified Guo’s composite solid electrolyte in S2; such a selection would be made with a reasonable expectation of success as Kim’s procedure teaches a suitability of this procedure for an intended purpose of producing a composite solid electrolyte, and because Kim’s solid electrolyte does not rely on a liquid electrolyte as required by Guo to avoid the risk of fire or explosion (Guo [0002-0004]) (MPEP 2144.07).
In the step of dissolving the mixed powder in a solvent, Kim further teaches a ratio of solvent to the polymer is at least 0.5 times the polymer mass to ensure complete dissolution of the polymers, while less than 25 times the polymer mass to enable the mixture to be suitably manufactured into a film form (Kim [0021]). While Kim does not teach a ratio of the solvent to the mixed powder as a whole, given that modified Guo’s composite solid electrolyte comprises a mixing ratio of polymer: salt: inorganic ceramic of 1:0.5:0.15 to 1:1:0.15 and a corresponding ratio of polymer to total ingredient mass is 1:1.65 to 1:2.15, i.e., roughly 1:2, one having ordinary skill in the art seeking to balance Kim’s considerations would dissolve the mixed powder in a solvent with an approximate range of 0.25-12.5 times the mass of the mixed powder before fully stirring and mixing, encompassing the claimed range of 5-8 times the mixed powder mass (MPEP 2144.05 II). Such an optimization would be made with a reasonable expectation of success as modified Guo’s would necessarily require the composite solid electrolyte to be capable of being formed into a film, i.e., a layer, in order to be compatible with forming a battery (Guo [0115]).
Kim further teaches that the composite polymer electrolyte is prepared by coating on a PTFE plate (“Teflon plate”) a conventional method known in the art so long as it is applied to a constant thickness (Kim [0023]); similarly, Guo requires a thickness of the solid electrolyte layer to be maintained within a range of 0.1-10 mm (Guo [0114]). While Guo and Kim do not explicitly teach or disclose the use of tape casting, R2R Processing teaches that tape casting may be suitably used to deposit a liquid while controlling the amount of liquid deposited and thus the coating thickness (R2R Processing pp. 346 ln. 337-344). As such, it would be obvious to select tape casting as a method of coating the mixed powder on a PTFE plate, as R2R Processing teaches a suitability of using this method to control the coating thickness as required by Kim and Guo (MPEP 2144.07).
Regarding claim 6, modified Guo discloses the method for improving the interface of the composite solid electrolyte in situ according to claim 5.
Modified Guo discloses that the composite solid electrolyte comprises an inorganic ceramic being garnet solid electrolyte, perovskite solid electrolyte, or NASICON solid electrolyte as non-limiting examples (Guo [0103], Li [0057]); while Guo does not disclose the selection of the organic polymer or lithium salt, Li, relied upon to teach substitution of a composite solid electrolyte for Guo’s solid electrolyte layer (Li [0057]), teaches the composite solid electrolyte wherein the organic polymer is polyethylene oxide and the lithium salt is lithium bis-trifluoromethane sulfonyl imide ([0075]).
Guo in view of Li does not specify a solvent for use with the method, but Kim discloses that dimethylformamide, acetonitrile, N-methylpyrrolidone or acetone may suitably be used as the solvent to dissolve the polymers in a solution for forming the composite solid electrolyte (Kim [0021-0022]); as such, it would be obvious before the effective filing date of the instant application for one having ordinary skill in the art to select one of these solvents for preparing the composite solid electrolyte (MPEP 2144.07)
Conclusion
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/E.C./Examiner, Art Unit 1751
/JONATHAN G LEONG/Supervisory Patent Examiner, Art Unit 1751 10/22/2025