A solid polymer electrolyte with polymer protein blend

Abstract

The present inventio provides a solid polymer electrolyte (SPE) comprising a spidroin and an ion conducting polymer wherein the ion conducting polymer is capable of conducting ions. The SPE of the present invention provides substantially better ionic conductivity than SPE without spidroin while providing better mechanical characteristic than SPE without spidroin.

Description

[0001] A Solid Polymer Electrolyte with Polymer Protein Blend

[0002] Background of the Invention

[0003] Global industrialization, fossil fuel use, and rapid economic growth have driven significant efforts to develop eco-friendly, low-pollution renewable energy sources.1, 2Lithium- ion batteries (LIBs) are valued for their high energy density, cycle performance, and reliability, making them popular for energy storage and conversion. However, liquid electrolytes in commercial batteries, despite optimization, pose safety risks due to poor chemical stability, flammability, and explosiveness, leading to incidents of spontaneous explosions in devices like phones, computers, and electric vehicles, especially during overcharging or short circuits.

[0004] Solid state batteries have been researched extensively since solid state battery may resolve issues associated with currently widely used Li ion batteries with liquid electrolyte such as leakage of organic solvents, fire safety and poor mechanical properties. Solid state batteries have also been of interest since they may provide high energy density. Polymers such as poly(ethylene oxide) (PEO) have been developed as solid polymer electrolyte (SPE) for solid state batteries due to its ability to dissolve and conduct lithium ions. However, high crystallinity and weak mechanical properties have prevented commercialization of SPE.

[0005] In addition, poor interfacial contact between electrolytes and electrodes of a solid state battery remains a significant challenge alongside mechanical properties and reduced crystallinity. This contact is crucial for electrochemical performance; poor contact leads to high interface impedance, and the periodic volume change of electrodes during the charge-discharge processes further exacerbates the interfacial contact.26Additionally, different phase boundaries hinder Li-i- transport, severely degrading performance.27, 28Thus, improving intcrfacial compatibility at the electrolyte / electrode interface is vital for high-performance ASSLIBs.29

[0006] Modifications to solid state electrolytes of solid state batteries by addition of filler such as SiO2, TiO2, A12O3, LilOGcP2S12, Lil.5A10.5Gcl.5(PO4)3, Li6.4La3Zrl.4Ta0.6O12 and metalorganic frameworks (MIL-53(A1)) have shown to improve the ionic conductivity and mechanical properties of solid polymer electrolytes (SPEs). However, preparation of these materials comes with high cost and low efficiency. Therefore, there is a need for a novel modified SPE based on ion conducting polymers such as PEO capable of providing high ionic conduction, strong mechanical properties as well as good interfacial contact that is also easy to prepare at commercially viable costs.

[0007] Summary of the Invention

[0008] The present invention provides a solid polymer electrolyte (SPE) comprising a spidroin and an ion conducting polymer wherein the ion conducting polymer is capable of conducting ions.

[0009] The present invention also provides a method of preparation of the SPE of claim 1, comprising the steps of mixing fibrous protein or spidroin with the ion conducting polymer and lithium salt; stirring the mixture for over 8 to over 48 hours; casting and drying the mixture of step b to form SPE; and curing the SPE of step c in a vacuum oven at more than about 20°C to about 50°C for more than about 24h to about 72 h.

[0010] The present invention further provides a solid polymer electrolyte (SPE) comprising a fibrous protein and an ion conducting polymer wherein the ion conducting polymer is capable of conducting ions.

[0011] Brief Description of the Drawings

[0012] FIG. 1 a illustrates interaction among poly(ethylene oxide) (PEG), fibrous protein such as MaSp2 spidroin and lithium bis(trifluoromcthanc sulfonimidc) (LiTFSI), and FIG. lb illustrates various ion transfer mechanisms in PEG.

[0013] FIG. 2 shows polarized optical microscopy (POM) images record at room temperature (RT) for: (a) PEO-LiTFSI; (b) PEG-LiTFSI-(10%)MaSp2; (c) PEO-LiTFSI-(15%)MaSp2; (d) PEG-LiTFSI-(20%)MaSp2; (e) PEO-LiTFSI-(25%)MaSp2; and (f) PEO-LiTFSI-(35%)MaSp2.

[0014] FIG. 3 illustrates an arrhenius plot of MaSp2 / PEO blends of the present invention containing 30 wt% LiTFSI at various temperature ranges from 30 to 80°C.

[0015] FIGs. 4a illustrates rate performance of LFPIP / MA2-20ILi cell at varying rates (0.05 C to 2 C) at 60 °C and FIG. 4b illustrate cycling performance of the LFPIP / MA2-20ILi cell at 0.2 C and 25 °C. FIG. 5a illustrates stress-strain curves of MaSp2 / PE0 blend film samples with different ratios of the Examples. FIG. 5b illustrates toughness calculated from the strcss-strain curves of MaSp2 / PE0 blend film samples with different ratios of the Examples. The error bars were calculated performing at least three replicates for each sample.

[0016] FIG. 6a illustrates tensile stress values obtained from strcss-strain curves of MaSp2 / PE0 blends with different ratios of the Examples. FIG. 6b illustrates elongation before break measured from the stress-strain curves of MaSp2 / PE0 blends with different ratios of the Examples. The error bars were calculated performing at least three replicates for each sample.

[0017] FIG. 7 illustrates an arrhenius plot of MaSpl / PEO blends of the present invention containing 30 wt% LiTFSI at various temperature ranges from 30 to 80°C.

[0018] FIG. 8a illustrates stress-strain curves of MaSpl / PEO blend film samples with different ratios of the Examples. FIG. 8b illustrates toughness calculated from the stress-strain curves of MaSpl / PEO blend film samples with different ratios of the Examples. The error bars were calculated performing at least three replicates for each sample.

[0019] FIG. 9a illustrates tensile stress values obtained from stress-strain curves of MaSpl / PEO blends with different ratios of the Examples. FIG. 9b illustrates elongation before break measured from the stress-strain curves of MaSpl / PEO blends with different ratios of the Examples. The error bars were calculated performing at least three replicates for each sample.

[0020] FIG. 10 illustrates an embodiment of the method of preparation of crosslinked PEO.

[0021] FIG. 11 illustrate rate performance of LFPIP / Li / MA2-20ILi cell at varying rates (0.05 C to 2 C) at 60 °C.

[0022] FIG. 12 are POM images of P / Li and P / Li / MA2-20 SPEs.

[0023] FIG. 13a illustrates stress-strain curves of P / Li / MA2 with different ratios of PEO / SpMa2 blend. FIG. 13b illustrates toughness values of P / Li / MA2 with different ratios of PEO / SpMa2 derived from the stress-strain curves of FIG. 13a.

[0024] FIG. 14a illustrates tensile strength and FIG. 14b illustrates elongation of P / Li / MA2 with different ratios of PEO / SpMa2 blend. FIG. 15a illustrates TGA curves of PE0 / MaSp2 SPE at various PEO / MaSp2 blend ratio of the present invention. FIG. 15b illustrates ATR-FTIR spectra of PE0 / MaSp2 SPE at various PEO / MaSp2 blend ratio of the present invention. FIG. 15c illustrates SAXS patterns of PE0 / MaSp2 SPE at various PEO / MaSp2 blend ratio of the present invention. FIG. 15d illustrates WAXS patterns of PE0 / MaSp2 SPE at various PEO / MaSp2 blend ratio of the present invention. FIG. 15e illustrates one-dimensional correlation functions of PEO / MaSp2 SPE at various PEO / MaSp2 blend ratio of the present invention. FIG. 15f illustrates changes in PEG lamellar thickness and amorphous region upon blending with MA2 of PEO / MaSp2 SPE at various PEO / MaSp2 blend ratio of the present invention.

[0025] FIG. 16a illustrates ATR-IR spectra of P / Li / MA2 SPE of the present invention with different ratios of PEO / SpMa2 blend. FIG. 16b illustrates schematic of interactions among MA2, PEG, and LiTFSI in P / Li / MA2 SPE of the present invention with different ratios of PEO / SpMa2 blend. FIG. 16c illustrates time evolution of PEG crystallinity of P / Li / MA2 SPE of the present invention with different ratios of PEO / SpMa2 blend. FIG. 16d illustrates WAXS profiles of P / Li / MA2 SPE of the present invention with different ratios of PEO / SpMa2 blend.

[0026] FIG. 17a illustrates TGA curves of P / Li / MA2 SPE of the present invention with different ratios of PEO / SpMa2 blend. FIG. 17b illustrates TGA curves of P / Li / MAl SPE of the present invention with different ratios of PEO / SpMal blend.

[0027] FIG. 18a illustrates LSV curves of neat PEO-based SPE and P / Li / MA2 SPE of the present invention with different ratios of PEO / SpMa2 blend at 80 °C. FIG. 18b illustrates polarization curves of the LilLi symmetric cell with P / Li / MA2-20 electrolyte, inset showing EIS curves before and after polarization. FIG. 18c illustrates Li electroplating / s tripping voltage distribution for LilLi symmetric batteries at 0.2 mA cm-1with a Li metal surface area of 1.96 cm2. FIG. 18d illustrates cycling performances of P / Li / MA2-15, P / Li / MA2-20, and P / Li / MA2- 25 electrolytes at 0.2 C and 60 °C. FIG. 18e illustrates charge / discharge voltage profiles of LFPIP / Li / MA2-20ILi battery across different cycles. FIG. 18f illustrates cycling performance of the LFPIP / Li / MA2-20ILi cell at 0.2 C and 25 °C. FIG. 18g illustrates initial charge and discharge curves of LFPIP / Li / MA2-20ILi battery at different rates at 60 °C.

[0028] FIG. 19 illustrates adhesion strength of neat PEO-based SPE, P / Li / MA2-20, and P / Li / MA2-35 on different substrates. FIG. 20a illustrates TGA curves of P / MA 1 SPE of the present invention with different ratios of PEO / SpMal blend. FIG. 20b illustrates SAXS profiles of P / Li / MAl SPE of the present invention with different ratios of PEO / SpMal blend. FIG. 20c illustrates DSC curves of P / Li / MAl SPE of the present invention with different ratios of PEO / SpMal blend. FIG. 20d illustrates WAXS profiles of P / Li / MAl SPE of the present invention with different ratios of PEO / SpMal blend.

[0029] FIG. 21a illustrates SAXS profiles of P / Li / MA2 SPE of the present invention with different ratios of PEO / SpMa2 blend. FIG. 21b illustrates SAXS profiles of P / Li / MAl SPE of the present invention with different ratios of PEO / SpMal blend.

[0030] Detailed Description of the Invention

[0031] The compositions of the present invention can comprise, consist of, or consist essentially of the essential elements and limitations of the invention described herein, as well as any of the additional or optional ingredients, components, or limitations described herein.

[0032] As used in the specification and claims, the singular form “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. For example, the term “a” cell includes a plurality of cells, including mixtures thereof.

[0033] “About” in the context of amount values refers to an average deviation of maximum ±20%, ±10%, ±5% or ±1% based on the indicated value. For example, an amount of about 500 kDa molecular weight refers to 500 kDa±100 kDa, 500 kDa±50 kDa, 500 kDa±25 kDa or 500 kDa±5 kDa molecular weight.

[0034] The terms “spider silk proteins,” and “spidroins” are used interchangeably herein, referring to both native and recombinant proteins. The term “major ampullate spidroins” (MaSps) refers to a specific subtype of spidroins, whose native forms are often found in spider dragline silk. MaSps generally comprise a repetitive region optionally flanked by N-terminal domains (NTDs) and C-terminal domains (CTDs). The terms “purification,” “separation,” and “isolation” are used interchangeably herein in connection to proteins, specifically referring to the separation of target proteins from other cellular materials, chemical substances, and / or impurities present in the mixture.

[0035] A “polynucleotide,” “nucleic acid,” or “nucleotide sequence” is a sequence of nucleotide bases, and may be RNA, DNA or DNA-RNA hybrid sequences (including both naturally occurring and non-naturally occurring nucleotide) but is preferably either single or double stranded DNA sequences. The term should also be understood to include, as equivalents, analogs of either RNA or DNA made from nucleotide analogs, and, as applicable to the embodiment being described, single (sense or antisense) and double- stranded polynucleotides. The terms “polynucleotide sequence” and “nucleotide sequence” are also used interchangeably herein.

[0036] An “amino acid sequence,” “peptide,” “polypeptide,” or “protein” is a sequence of amino acids (including both naturally occurring and non-naturally occurring amino acids), which may be found in native proteins or may be artificially engineered as recombinant proteins or parts thereof. The term should also be understood to include, as equivalents, polypeptides with additional modifications, including but not limited to phosphorylation, glycosylation, lipidation, etc.

[0037] A “coding sequence” or a sequence which “encodes” a particular protein, is a nucleic acid sequence which is transcribed (in the case of DNA) and translated (in the case of mRNA) into a polypeptide in vitro or in vivo when placed under the control of appropriate regulatory sequences. The boundaries of the coding sequence are determined by a start codon at the 5’ (amino) terminus and a translation stop codon at the 3’ (carboxy) terminus. A coding sequence can include, but is not limited to, cDNA from prokaryotic or eukaryotic mRNA, genomic DNA sequences from prokaryotic or eukaryotic DNA, and even synthetic DNA sequences. A transcription termination sequence will usually be located 3’ to the coding sequence.

[0038] As used herein, the term “gene” or “recombinant gene” refers to a nucleic acid comprising an open reading frame encoding a polypeptide, including both exon and (optionally) intron sequences.

[0039] As used herein, the term “recombinant protein” or “engineered protein” refers to a protein translated from non-naturally occurring nucleotide sequences, which may comprise artificially designed and engineered sequences, and may further comprise some naturally occurring sequences in combination with artificial sequences.

[0040] As used herein, “sequence identity” and “% identity,” refers to the value determined by comparing two optimally aligned sequences over a comparison window, wherein a portion of the sequence in the comparison window may comprise additions or deletions as compared to the reference sequence for optimal alignment of the two sequences. The number of positions at which identical amino acid residues occur in both sequences is determined, yielding the number of matched positions, which is divided by the total number of positions in the window of comparison and the result multiplied by 100 to yield the percentage of sequence identity. The comparison window is the entire length of the sequence being referred to unless indicated otherwise.

[0041] As used herein, “% similarity” is calculated as described for “% identity,” with the exception that the hydrophobic residues Ala, Vai, Phe, Pro, Leu, He, Trp, Met, and Cys are similar; the basic residues Lys, Arg, and His are similar; the acidic residues Glu and Asp are similar; and the hydrophilic, uncharged residues Gin, Asn, Ser, Thr, and Tyr are similar. The remaining natural amino acid Gly is not similar to any other amino acid in this context.

[0042] As used herein, “ionic conductivity” is a measure of a substance's tendency towards ionic conduction. Ionic conduction is the movement of ions. Ionic conductivity is calculated according to the equation: o=L / (R+S) wherein R( ) is the bulk electrolyte resistance, L(cm) is the thickness of the SPE and S (cm2) is the area of the electrode.

[0043] A variety of solid-state batteries are in research and development. One such solid-state battery being developed uses solid polymer electrolytes (SPE) comprising polymers capable of transmitting ions. Such ion conducting polymers may comprise polyethylene oxide (PEO), polyelthyleneglycol (PEG), polyvinyl alcohol (PVA), etc.... Although safer than the widely used batteries with liquid or gel electrolytes, one major issue with SPE is low ion conductivity. The low conductivity stems partly from the fact that solid phase of the SPE does not allow flow of ions as easily as liquid or gel electrolytes. Furthermore, it has been theorized that the low conductivity of SPE also partly stem from crystallinity of the SPE which hinders ion movement.

[0044] Another major issue with Li ion solid-state batteries and Li ion batteries in general is need for superior mechanical properties capable of preventing mechanical failure that can expose Li to the ambient air or lead to short circuiting of the battery. Superior mechanical properties of the electrolyte can also mitigate or prevent Li dendrite formation. “The failures of batteries using lithium metal anodes may be involved three reasons. Firstly, the unrestrained lithium dendrites penetrate the SPE films causing the short circuit of cells. Secondly, the side reactions between lithium metal and electrolyte form SEI films resulting in the low efficiency. The large Li dendrites can be wrapped by the SEI films and converted to the dead lithium. Both of the SEI films and dead Li can increase the polarization and reduce the efficiency of cells. Lastly, the porous lithium dendrite growth causes the volume change and influences the battery performance. The lithium dendrites are the main reason causing the cells with poor safety and low efficiency during the cycling. The improved cycling performance of the blend SPE based cells may ascribe to the improved mechanical strength and electrochemical properties of TPU / PEO electrolyte. The lithium dendrite will grow rapidly at the absence of the mechanical restrains.”50In addition, as mentioned above poor interfacial contact between electrolytes and electrodes remains a significant challenge alongside mechanical properties and reduced crystallinity.

[0045] It is known in the art that measures to improve electrolyte mechanical properties generally results in lower ion conductivity and vice versa as taught in Tao et al.50However, the inventors have unexpectedly discovered that blending PEO with fibrous proteins such as spidroin significantly enhances the resulting SPE’s mechanical properties while increases ion conductivity as explained in further detail in the Examples below in connection with the figures, making the PEO / spidroin composite ideal for SPE applications. Therefore, the present invention provides a solid state electrolyte comprising a blend of ion conducting polymer such as PEO with natural or recombinant spidroin or fibrous protein with sufficient characteristics of the spidroin which not only substantially increases ion conductivity but also substantially improves mechanical properties as well as interfacial compatibility at the electrolyte / electrode interface. Natural and recombinant spider silk protein (rSSP) comprises a repeating REP domain wherein the REP domain comprises a plurality of repeating units R. In addition, natural and recombinant spider silk protein (rSSP) may further comprise non-repeating N-terminal domain (NTD) and non-repeating C-terminal domain (CTD) flanking the REP domain.

[0046] Examples below in connection with FIG. la illustrates a solid-state polymer electrolyte (SPE) comprising a blend of spidroin and PEO and interaction of spidroin with the ion conducting polymer. For example, FIG. la illustrates hydrogen bond interaction between N-H group of the spidroin and C-O-C group of the PEO resulting in soft segments of the SPE. FIG. la further illustrates spidroin-spidroin interaction resulting in hard segments of the SPE as well as conduction of lithium ion by PEO and spidroin. Without being bound to theory, the hydrogen bond reduces crystallinity of the PEO / spidroin electrolyte compared to electrolyte with PEO alone, improving ion conductivity. FIGs. la and lb further illustrate how the protein and the polymer may conduct ions. The parameter xcshown in Table 1 indicates relative percentage of crystallinity of SPEs calculated according to the equation:

[0047] Table 1. The outline of thermodynamics parameters for the neat PEC), and PEO-based SPEs with different ratios.

[0048] Table 1 summarizes results of the glass transition temperature (Tg), crystallization point (Tc), crystallization enthalpy (AHC), melting point (Tm), melting enthalpy (AHm), and crystallinity (Xc) measurements of the SPEs obtained through DSC. As seen in Table 1, reduction in of about 30% results from as little as 10% blend of spidroin. Data also indicates %cis further reduced with higher spidroin content in the SPE. The POM images of FIG. 2 illustrate decrease in crystallinity visually. As proteins other than spidroins are capable of forming the same hydrogen bond with ion transmitting polymer such as PEO, proteins other than spidroin may also be used to blend with ion transmitting polymer such as PEO to form SPE such as fibrous protein other than spidroins.

[0049] As mentioned above, although blending materials with ion conducting polymer such as PEG or PEO can improve ion conductivity, the blend usually results in a material with weaker and inferior mechanical properties.50Surprisingly, blending the spidroin or fibrous protein with sufficient characteristics of the spidroin with PEO not only results in a solid-state electrolyte with substantially higher ion conductivity then that made with pure PEO, the spidroin / PEO blend also provides superior mechanical properties.

[0050] As shown in FIG. 3, various embodiments of the SPE comprising MaSp2 and PEO blend of the present invention at various blend ratios provide markedly higher ionic conductivity than PEO alone at various temperatures ranging from about 30°C to 80°C. The increase in ionic conductivity is seen for MaSp2 / PEO blend ratio as low as about 10 / 90 and increases with rise in the MaSp2 / PEO blend ratio. The increase in ionic conductivity levels off at near maximum with MaSp2 / PEO blend ratio of around 20 / 80 by weight and decreases towards ionic conductance of pure PEO with blend ratio by weight percentage of greater than 25 / 75. FIGs. 4a and 4b illustrate cycling profile of battery made with SPE comprising MaSp2 / PEO 20 / 80 blend of the present invention demonstrating high coulombic efficiency and stable charging / discharging characteristics. FIG. 7 also illustrates that blending MaSpl with PEO also results in substantially higher ionic conductivity with the highest ionic conductivity achieved at 10 / 90 blend of the three blends 10 / 90, 20 / 80 and 30 / 70.

[0051] FIG. 5a illustrates stress and strain curves, and FIG. 5b illustrates toughness calculated from the stress-strain curves of MaSp2 / PEO blend SPE of the present invention at various blend ratios. As shown in FIG. 5b, MaSp2 / PEO blend ratios by weight percentage between about 10 / 90 to about 50 / 50 achieve substantially higher toughness than pure PEO, and, remarkably, MaSp2 / PEO ratio by weight percentage of 25 / 75 achieves nearly 10 times the toughness of pure PEO. Furthermore, FIG. 6a illustrates tensile stress values derived from stress-strain curves of various MaSp2 / PEO blends ratios, and FIG. 6b illustrates elongation measured from the curves. As shown in FIG. 6a, blending MaSp2 with PEO at all ratios results in a material capable of handling higher tensile stress than pure PEO, and higher MaSp2 / PEO blend ratio results in higher tensile stress handling capability. FIG. 6b shows that the MaSp2 blend is capable of farther elongation before break than pure PEO for blends equal or less than about 35 with maximum occurring at ratio of about 25.

[0052] Similarly, FIG. 8a illustrates stress and strain curves, and FIG. 8b illustrates toughness calculated from the stress-strain curves of MaSpl / PEO blend SPE of the present invention at various blend ratios. As shown in FIG. 8b, MaSpl / PEO blend ratios by weight percentage between about 5 / 90 to about 40 / 60 achieve substantially higher toughness than pure PEO, and, remarkably, MaSpl / PEO ratio by weight percentage of 15 / 85 to 20 / 80 achieves nearly 6 times the toughness of pure PEO. Furthermore, FIG.9a illustrates tensile stress values derived from stress-strain curves of various MaSpl / PEO blends ratios, and FIG. 9b illustrates elongation measured from the curves. As shown in FIG. 9a, blending MaSpl with PEO at all ratios results in a material capable of handling higher tensile stress than pure PEO, and higher MaSpl / PEO blend ratio results in higher tensile stress handling capability. FIG. 9b shows that the MaSpl blend is capable of farther elongation before break than pure PEO for blends of about 10 / 90- 15 / 85.

[0053] Therefore, the present invention provides a solid polymer electrolyte (SPE) comprising spidroin and an ion conducting polymer wherein the ion conducting polymer is capable of conducting ions. In an embodiment, the ion comprises lithium ion. In an embodiment, the ion conducting polymer is blended with the spidroin. In an embodiment, the ion conducting polymer complexes with the spidroin in the blend. In an embodiment, the ion conducting polymer complexes with the spidroin in the blend via interaction between functional groups of the spidroin and the ion conducting polymer. In an embodiment, the spidroin comprises one or more N-H group and the ion conducting polymer comprises one or more C-O-C group and wherein the spidroin complexes with the ion conducting polymer via hydrogen bond between N-H group of the spidroin and C-O-C group of the ion conducting polymer. In an embodiment, the ion conducting polymer complexing with the spidroin results in reduction in SPE crystallinity. In an embodiment, the blending or complexing of the spidroin with the ion conducting polymer reduces crystallinity of the SPE of the present invention by about 5% to about 100% such as about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95% or about 100% including any percentage or percentage ranges falling within these values. In an embodiment, the ratio of the spidroin to the ion-conducting polymer by weight is between about 5 / 95 to about 95 / 5 such as about 5 / 95, about 10 / 90, about 15 / 85, about 20 / 80, about 25 / 75, about 30 / 70, about 35 / 65, about 40 / 60, about 45 / 55, about 50 / 50, about 55 / 45, about 60 / 40, about 65 / 35, about 70 / 30, about 75 / 25, about 80 / 20, about 85 / 15, about 90 / 10 or about 95 / 5 including any ratio or ratio ranges falling within these values. In an embodiment, the ratio of the spidroin to the ion-conducting polymer by weight is between about 10 / 95 to about 35 / 5 such as 10 / 90, about 15 / 85, about 20 / 80, about 25 / 75, about 30 / 70, or about 35 / 65 including any ratio or ratio ranges falling within these values.

[0054] In an embodiment, the ion-conducting polymer comprises PEG, PEO, PVA, polyacrylonitrile (PAN), PS, polymethyl methacrylate (PMMA), poly vinylidene fluoride (PVDF), polyvinyl pyrrolidone (PVP). In an embodiment, the ion-conducting polymer is crosslinked. In an embodiment, the PEO is crosslinked with PETA. In an embodiment, the PEO is crosslinked with PEGDA. In an embodiment, the PEO is crosslinked with TMPTA.

[0055] In an embodiment, the spidroin of the present invention comprises crystalline and amorphous regions. In an embodiment, the ratio of crystalline to amorphous region by weight, number of regions or number of structures is about 10:1 to about 1:10 such as about 10:1, about 9:1, about 8:1, about 7:1, about 6:1, about 5:1, about 4:1, about 3:1, about 2:1, about 1:1, about 1:2, about 1:3, about 1:4, about 1:5, about 1:6, about 1:7, about 1:8, about 1:9 or about 1:10 including any ratios or ratio ranges falling within these values. In an embodiment, the ratio of crystalline to amorphous region by weight, number of regions or number of structures is about 1:10 to about 5:10 such as about 1:10, about 1.5:10, about 2:10, about 2.5:10, about 3:10, about 3.5:10, about 4:10, about 4.5:10 or about 5:10, including any ratios or ratio ranges falling within these values. In an embodiment, the spidroin of the present invention comprises beta sheet and alpha helix structures. In an embodiment, the ratio of beta sheet to alpha helix structures by weight or number of structures in the spidroin of the present invention is about 10:1 to about 1 : 10 such as about 10: 1 , about 9: 1 , about 8:1 , about 7:1 , about 6:1 , about 5:1 , about 4: 1 , about 3:1, about 2:1, about 1:1, about 1:2, about 1:3, about 1:4, about 1:5, about 1:6, about 1:7, about 1:8, about 1:9 or about 1:10 including any ratios or ratio ranges falling within these values. In an embodiment, the ratio of beta sheet to alpha helix structures by weight or number of structures in the spidroin of the present invention is about 1:2 to about 2:1 such as about 1:2, about 1:1.5, about 1 :1 , about 1.5:1 or about 2: 1 , including any ratios or ratio ranges falling within these values.

[0056] In an embodiment, the spidroin of the present invention comprises beta-sheet, beta-spiral, 3io helix, structured putative structures or a combination thereof. In an embodiment, ratio of the number of beta- sheet putative structures to the number of other putative structures in the spidroin of the present invention is about 10:1 to about 1:10 such as about 10:1, about 9:1, about 8:1, about 7:1, about 6:1, about 5:1, about 4:1, about 3:1, about 2:1, about 1:1, about 1:2, about 1:3, about 1:4, about 1:5, about 1:6, about 1:7, about 1:8, about 1:9 or about 1:10 including any ratios or ratio ranges falling within these values. In an embodiment, ratio of the number of beta-sheet putative structures to the number of other putative structures in the spidroin of the present invention is about 1:2 to about 1:6 such as about 1:2, about 1:2.5, about 1:3, about 1:3.5, about 1:4, about 1:4.5, about 1:5, about 1:5.5, or about 1:6 including any ratios or ratio ranges falling within these values.

[0057] In an embodiment, the beta- sheet putative structure comprises protein domain with amino acid motif (GAn) / An. In an embodiment, the beta-spiral putative structure comprises protein domain with amino acid sequence motif (GPGXX)n. In an embodiment, the 3io helix putative structure comprises protein domain with amino acid sequence motif (GGX)n. In an embodiment, the amino acid sequence of the spidroin of the present invention comprises amino acid sequence motif (GAn) / An, (GPGXX)Uor (GGX)nor a combination thereof. The different amino acid motifs present in MA and Flag silk are correlated with their putative structure and their impact on the final properties of the spidroin. In an embodiment the ratio of motifs (GAn) / An: (GPGXX)n: (GGX)n is about 1:3:3 to about 2:3:3 in the beta-sheet putative structure.

[0058] In an embodiment, the amino acid motif (GAn) / Ancomprises about 1% to about 95% of the amino acid sequence of the spidroin of the present invention such as about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 15,%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90% or about 95% including any percentage or percentage ranges falling within these values. In an embodiment, the amino acid motif (GPGXX)ncomprises about 1% to about 95% of the amino acid sequence of the spidroin of the present invention such as about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 15,%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90% or about 95% including any percentage or percentage ranges falling within these values. In an embodiment, the amino acid motif (GGX)ncomprises about 1% to about 95% of the amino acid sequence of the spidroin of the present invention such as about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 15,%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90% or about 95% including any percentage or percentage ranges falling within these values. In an embodiment, the length ratio of (GAn) / An: (GPGXX)n : (GGX)nis about 7:15:12 to about 10:15:12 such as about 7:15:12, about 8:15:12, about 9:15:12, or about 10:15:12, including any ratio or ratio ranges falling within these values.

[0059] In an embodiment, the spidroin of the present invention comprises about 10 to 10,000 amino acids such as about 10, about 100, about 200, about 300, about 400, about 500, about 1000, about 2500, about 3000, about 3500, about 4000, about 4500, about 5000, about 5500, about 6000, about 6500, about 7000, about 7500, about 8000, about 8500, about 9000, about 9500 or about 10000 including any number or number ranges falling within these values. In an embodiment, the spidroin of the present invention is about IkDa to about 600kDa such as about IkDa, about 2kDa, about 3kDa, about 4kDa, about 5kDa, about lOkDa, about 20kDa, about 30kDa, about 40kDa, about 50kDa, about 60kDa, about 70kDa, about 80kDa, about 90kDa, about lOOkDa, about 150kDa, about 200kDa, about 250kDa, about 300kDa, about 400kDa, about 500kDa, about 550kDa, about 600kDa, about 650kDa, about 700kDa, about 750kDa, about 800kDa, about 850kDa, about 900kDa, about 950kDa, about lOOOkDa, about 1500kDa, about 2000kDa, about 2500kDa, about 3000kDa, about 3500kDa, about 4000kDa, about 4500kDa, about 5000kDa, about 55OOkDa, about 6000kDa, about 6500kDa, about 7000kDa, about 7500kDa, about 8000kDa, about 8500kDa, about 9000kDa, about 9500kDa or about lOOOkDa including any weight or weight ranges falling within these values.

[0060] In an embodiment, the spidroin of the present invention comprises repeating REP domain. In an embodiment, the amino acid sequence of the REP domain of the spidroin of the present invention is about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95% or about 100% identical or similar to SEQ ID NO. 1 or SEQ ID NO. 2. an embodiment, the amino acid sequence of each of the REP domain of the spidroin of the present invention is about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95% or about 100% identical or similar to SEQ ID NO. 1 or SEQ ID NO. 2.

[0061] SEQ ID NO. 1: (GAGAAAAAASGAGQGGYGRQGGTS)n

[0062] SEQ ID NO. 2: (GPGGYGPGQQGPSGPAAAAAAGPGGYGPGQQTS)n

[0063] Since the spidroin of the present invention is a type of fibrous protein, in an embodiment, any embodiment of the spidroin of the present invention may be substituted with a fibrous protein with sufficient characteristics of the spidroin in any embodiment of the SPE of the present invention. In an embodiment, a fibrous protein comprises one or more polypeptides wherein at least one or more polypeptides form one or more elongated or fibrous polypeptide chain. In an embodiment, a fibrous protein may further comprise regions that comprise globular or otherwise non-elongated or non-fibrous regions. In an embodiment, the fibrous protein of the present invention comprises a repetitive region. In an embodiment, the fibrous protein of the present invention comprises at least about 5% to about 100% of polypeptides that form elongated or fibrous polypeptide chain such as about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95% or about 100% including any percentage or percentage ranges falling within these values.

[0064] Therefore, the present invention also provides a SPE comprising a fibrous protein and an ion conducting polymer wherein the ion conducting polymer is capable of conducting ions. In an embodiment, the ion comprises lithium ion. In an embodiment, the ion conducting polymer is blended with the fibrous protein. In an embodiment, the ion conducting polymer complexes with the fibrous protein in the blend. In an embodiment, the ion conducting polymer complexes with the fibrous protein in the blend via interaction between functional groups of the fibrous protein and the ion conducting polymer. In an embodiment, the fibrous protein comprises one or more N-H groups and the ion conducting polymer comprises one or more C-O-C groups, and the N-H group of the fibrous protein interacts with the C-O-C group of the ion conducting polymer. In an embodiment, the fibrous protein comprises one or more N-H groups and the ion conducting polymer comprises one or more C-O-C groups, and the N-H group of the fibrous protein interacts with the C-O-C group of the ion conducting polymer via hydrogen bond. In an embodiment, the ion conducting polymer complexing with the fibrous protein results in reduction in crystallinity of the SPE. In an embodiment, the blending or complexing of the protein with the polymer reduces crystallinity of the SPE by about 5% to about 100% such as about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95% or about 100% including any percentage or percentage ranges falling within these values. In an embodiment, the ratio of the fibrous protein to ion-conducting polymer ratio by weight is between about 5 / 95 to about 95 / 5 such as about 5 / 95, about 10 / 90, about 15 / 85, about 20 / 80, about 25 / 75, about 30 / 70, about 35 / 65, about 40 / 60, about 45 / 55, about 50 / 50, about 55 / 45, about 60 / 40, about 65 / 35, about 70 / 30, about 75 / 25, about 80 / 20, about 85 / 15, about 90 / 10 or about 95 / 5 including any ratio or ratio ranges falling within these values.

[0065] In an embodiment, the ion conducting polymer comprises PEG, PEO, PVA, polyacrylonitrile (PAN), PS, polymethyl methacrylate (PMMA), poly vinylidene fluoride (PVDF), polyvinyl pyrrolidone (PVP).

[0066] In an embodiment, the fibrous protein of the present invention comprises crystalline and amorphous regions. In an embodiment, the ratio of crystalline to amorphous region by weight, number of regions or number of structures is about 10:1 to about 1:10 such as about 10:1, about 9:1, about 8:1, about 7:1, about 6:1, about 5:1, about 4:1, about 3:1, about 2:1, about 1:1, about 1:2, about 1:3, about 1:4, about 1:5, about 1:6, about 1:7, about 1:8, about 1:9 or about 1:10 including any ratios or ratio ranges falling within these values. In an embodiment, the ratio of crystalline to amorphous region by weight, number of regions or number of structures is about 1:10 to about 5:10 such as about 1:10, about 1.5:10, about 2:10, about 2.5:10, about 3:10, about 3.5:10, about 4:10, about 4.5:10 or about 5:10, including any ratios or ratio ranges falling within these values. In an embodiment, the fibrous protein of the present invention comprises beta sheet and alpha helix structures. In an embodiment, the ratio of beta sheet to alpha helix structures by weight or number of structures is about 10:1 to about 1:10 such as about 10:1, about 9:1, about 8:1, about 7:1, about 6:1, about 5:1, about 4:1, about 3:1, about 2:1, about 1:1, about 1:2, about 1:3, about 1:4, about 1:5, about 1:6, about 1:7, about 1:8, about 1:9 or about 1 : 10 including any ratios or ratio ranges falling within these values. In an embodiment, the ratio of beta sheet to alpha helix structures by weight or number of structures in the fibrous protein of the present invention is about 1:2 to about 2:1 such as about 1:2, about 1:1.5, about 1:1, about 1.5:1 or about 2:1, including any ratios or ratio ranges falling within these values.

[0067] In an embodiment, the fibrous protein of the present invention comprises beta-sheet, betaspiral, 3io helix, structured putative structures or a combination thereof. In an embodiment, ratio of the number of beta-sheet putative structures to the number of other putative structures in the protein of the present invention is about 10:1 to about 1:10 such as about 10:1, about 9:1, about 8:1, about 7:1, about 6:1, about 5:1, about 4:1, about 3:1, about 2:1, about 1:1, about 1:2, about 1:3, about 1:4, about 1:5, about 1:6, about 1:7, about 1:8, about 1:9 or about 1:10 including any ratios or ratio ranges falling within these values. In an embodiment, ratio of the number of betasheet putative structures to the number of other putative structures in the fibrous protein of the present invention is about 1:2 to about 1:6 such as about 1:2, about 1:2.5, about 1:3, about 1:3.5, about 1:4, about 1:4.5, about 1:5, about 1:5.5, or about 1:6 including any ratios or ratio ranges falling within these values.

[0068] In an embodiment, the fibrous protein of the present invention comprises about 10 to 10,000 amino acids such as about 10, about 100, about 200, about 300, about 400, about 500, about 1000, about 2500, about 3000, about 3500, about 4000, about 4500, about 5000, about 5500, about 6000, about 6500, about 7000, about 7500, about 8000, about 8500, about 9000, about 9500 or about 10000 including any number or number ranges falling within these values. In an embodiment, the fibrous protein of the present invention is about IkDa to about 600kDa such as about IkDa, about 2kDa, about 3kDa, about 4kDa, about 5kDa, about lOkDa, about 20kDa, about 30kDa, about 40kDa, about 50kDa, about 60kDa, about 70kDa, about 80kDa, about 90kDa, about lOOkDa, about 150kDa, about 200kDa, about 250kDa, about 300kDa, about 400kDa, about 500kDa, about 550kDa, about 600kDa, about 650kDa, about 700kDa, about 750kDa, about 800kDa, about 850kDa, about 900kDa, about 950kDa, about lOOOkDa, about 1500kDa, about 2000kDa, about 2500kDa, about 3000kDa, about 3500kDa, about 4000kDa, about 4500kDa, about 5000kDa, about 5500kDa, about 6000kDa, about 6500kDa, about 7000kDa, about 7500kDa, about 8000kDa, about 8500kDa, about 9000kDa, about 9500kDa or about lOOOkDa including any weight or weight ranges falling within these values. In an embodiment, the amino acid motif (GAn) / Ancomprises about 1 % to about 95% of the amino acid sequence of the fibrous protein of the present invention such as about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 15,%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90% or about 95% including any percentage or percentage ranges falling within these values. In an embodiment, the amino acid motif (GPGXX)Ucomprises about 1% to about 95% of the amino acid sequence of the fibrous protein of the present invention such as about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 15,%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90% or about 95% including any percentage or percentage ranges falling within these values. In an embodiment, the amino acid motif (GGX)ncomprises about 1% to about 95% of the amino acid sequence of the fibrous protein of the present invention such as about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 15,%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90% or about 95% including any percentage or percentage ranges falling within these values. In an embodiment, the length ratio of (GA n) / An: (GPGXX)n : (GGX)nis about 7:15:12 to about 10:15:12 such as about 7:15:12, about 8:15:12, about 9:15:12, or about 10:15:12, including any ratio or ratio ranges falling within these values.

[0069] In an embodiment, fibrous protein of the present invention comprises a repeating REP domain. In an embodiment, the amino acid sequence of the REP domain of the fibrous protein of the present invention is about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95% or about 100% identical or similar to SEQ ID NO. 1 or SEQ ID NO. 2. In an embodiment, the amino acid sequence of each of the REP domain of the fibrous protein of the present invention is about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95% or about 100% identical or similar to SEQ ID NO. 1 or SEQ ID NO. 2.

[0070] In an embodiment, any embodiment of the SPE of the present invention further comprises lithium salt. In an embodiment, the lithium salt comprises lithium bis(trifluoromethane sulfonimide) (LiTFSI), lithium perchlorate (LiCIC ), lithium hexafluorophosphate (LiPFe), lithium tctrafluoroboratc (LiBF4), lithium hcxafluoroarscnatc (LiAsF6), lithium trifluoromethanesulfonate (LiTf), lithium bis(trifluoromethanesulfonimide) (LiBETI), 1,2,3- dithiazolidine-4,4,5,5-tetrafluoro-l,l,3,3-tetraoxide (LiCTFSI), lithium-bis(oxalate) borate (LiBOB) or a combination thereof.

[0071] In an embodiment, the SPE comprising spidroin of the present invention further comprises a lithium salt resulting in an ion conducting polymer / lithium salt / spidroin (P / Li / Spidroin) SPE. In an embodiment, the ion conducting polymer complexing with the spidroin results in reduction in P / Li / Spidroin SPE crystallinity. In an embodiment, the blending or complexing of the spidroin with the ion conducting polymer reduces crystallinity of the P / Li / Spidroin SPE of the present invention by about 5% to about 100% such as about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95% or about 100% including any percentage or percentage ranges falling within these values. In an embodiment, the ratio of the spidroin to the ion-conducting polymer by weight in the P / Li / Spidroin SPE of the present invention is between about 5 / 95 to about 95 / 5 such as about 5 / 95, about 10 / 90, about 15 / 85, about 20 / 80, about 25 / 75, about 30 / 70, about 35 / 65, about 40 / 60, about 45 / 55, about 50 / 50, about 55 / 45, about 60 / 40, about 65 / 35, about 70 / 30, about 75 / 25, about 80 / 20, about 85 / 15, about 90 / 10 or about 95 / 5 including any ratio or ratio ranges falling within these values. In an embodiment, the molar ratio of PEO / Li by weight is about 25:1 to about 5:1 such as about 25:1, about 20:1, about 15:1, about 10:1, or about 5:1 including any ratios or ratio ranges falling within these values.

[0072] As shown in FIG. 3, various embodiments of the P / Li / Spidroin SPE of the present invention comprising PEG, LiTFSI lithium salt and MaSp2 with MaSp2 and PEO blended at various weight ratios provide markedly higher ionic conductivity than PEO and LiTFSI alone without any spidroin at various temperatures ranging from about 30°C to 80°C. The increase in ionic conductivity is seen for MaSp2 / PEO weight ratio as low as about 10 / 90 and increases with rise in the MaSp2 / PEO blend ratio. The increase in ionic conductivity levels off at near maximum with MaSp2 / PEO blend ratio of around 20 / 80 by weight and decreases towards ionic conductance of pure PEO with blend ratio by weight percentage of greater than 35 / 75. FIG. 11 illustrates cycling profile of battery made with SPE comprising MaSp2 / PE0 20 / 80 blend of the present invention illustrates high coulombic efficiency and stable charging / discharging characteristics. FIG. 7 also illustrates that blending MaSpl with PEO and LiFTSI lithium salt also results in substantially higher ionic conductivity with the highest ionic conductivity achieved at 10 / 90 blend of the three blends 10 / 90, 20 / 80 and 30 / 70. FIG. 12 visually illustrates that adding spidroin MaSp2 to PEO and lithium salt substantially reduces crystallinity, providing far better conductivity.

[0073] FIG. 13a illustrates stress and strain curves, and FIG. 13b illustrates toughness calculated from the stress-strain curves of P / Li / MaSp2 SPE of the present invention at various blend ratios. As shown in FIG. 13b, P / Li / MaSp2 SPE of the present invention with MaSp2 / PEO blend ratios by weight percentage between about 10 / 90 to about 35 / 50 achieve substantially higher toughness than pure P / Li, and, remarkably, MaSp2 / PEO ratio by weight percentage of 20 / 80 achieves nearly 8 times the toughness of pure PEO / Li. Furthermore, FIG. 14a illustrates tensile stress values derived from stress-strain curves of various MaSp2 / PEO blends ratios of P / Li / MaSp2 SPE of the present invention, and FIG. 14b illustrates elongation measured from the curves. As shown in FIG. 14a, blending MaSp2 with PEO at all ratios results in a P / Li / MaSp2 SPE material capable of handling higher tensile stress than pure PEO / Li, and higher MaSp2 / PEO blend ratio results in higher tensile stress handling capability of P / Li / MaSp2 SPE. FIG. 14b shows that P / Li / MaSp2 SPE is capable of farther elongation before break than pure PEO / Li for MaSP2 / PEO blends equal or less than about 35 with maximum occurring at ratio of about 15.

[0074] FIG. 19 illustrates substantially improved interfacial adhesion when spidroin MaSp2 is added to the P / Li / MaSp2 SPE of the present invention at PEO and MaSp2 ratios of 20 and 35 for various cathode and anode materials. Improvement in adhesion ranges from almost 3 folds to over 5 fold higher adhesion.

[0075] Therefore, in an embodiment, the SPE comprising spidroin of the present invention further comprises a lithium salt resulting in an ion conducting polymer / lithium salt / spidroin (P / Li / Spidroin) SPE. In an embodiment, the ion conducting polymer complexing with spidroin results in reduction in P / Li / Spidroin SPE crystallinity. In an embodiment, the blending or complexing of the spidroin with the ion conducting polymer reduces crystallinity of the P / Li / Spidroin SPE of the present invention by about 5% to about 100% such as about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95% or about 100% including any percentage or percentage ranges falling within these values. In an embodiment, the ratio of the spidroin to the ion-conducting polymer by weight in the P / Li / Spidroin SPE of the present invention is between about 5 / 95 to about 95 / 5 such as about 5 / 95, about 10 / 90, about 15 / 85, about 20 / 80, about 25 / 75, about 30 / 70, about 35 / 65, about 40 / 60, about 45 / 55, about 50 / 50, about 55 / 45, about 60 / 40, about 65 / 35, about 70 / 30, about 75 / 25, about 80 / 20, about 85 / 15, about 90 / 10 or about 95 / 5 including any ratio or ratio ranges falling within these values.

[0076] In an embodiment, the SPE comprising fibrous protein of the present invention further comprises a lithium salt resulting in an ion conducting polymer / lithium salt / fibrous protein (P / Li / FP) SPE. In an embodiment, the ion conducting polymer complexing with the fibrous protein results in reduction in P / Li / FB SPE crystallinity. In an embodiment, the blending or complexing of the fibrous protein with the ion conducting polymer reduces crystallinity of the P / Li / FB SPE of the present invention by about 5% to about 100% such as about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95% or about 100% including any percentage or percentage ranges falling within these values. In an embodiment, the ratio of the fibrous protein to the ion-conducting polymer by weight in the P / Li / FB SPE of the present invention is between about 5 / 95 to about 95 / 5 such as about 5 / 95, about 10 / 90, about 15 / 85, about 20 / 80, about 25 / 75, about 30 / 70, about 35 / 65, about 40 / 60, about 45 / 55, about 50 / 50, about 55 / 45, about 60 / 40, about 65 / 35, about 70 / 30, about 75 / 25, about 80 / 20, about 85 / 15, about 90 / 10 or about 95 / 5 including any ratio or ratio ranges falling within these values.

[0077] The present invention also provides a method of reducing crystallinity of a SPE comprising the step of blending any embodiment of the spidroin or fibrous protein of the present invention into the SPE.

[0078] The present invention also provides a method of increasing ionic conductivity of a SPE comprising the step of blending any embodiment of the spidroin or fibrous protein of the present invention into the SPE. The present invention also provides a method of strengthening mechanical properties of a SPE comprising the step of blending any embodiment of the spidroin or fibrous protein of the present invention into the SPE.

[0079] The present invention also provides a method of preparation 1000 of the SPE of the present invention. The method of preparation of the SPE of the present invention begins with step 1010 of blending any embodiment of the spidroin or fibrous protein of the present invention with any embodiment of the ion conducting polymer of the present invention and / or any embodiment of the lithium salt of the present invention. In an embodiment, the components are mixed within hexafluoroisopropanol (HFIP). In step 1020, the mixture is then stirred for over 8 to over 48 hours such as about 8 hours, about 10 hours, about 12 hours, about 14 hours, about 16 hours, about 18 hours, about 20 hours, about 24 hours, about 28 hours, about 32 hours, about 38 hours, about 42 hours or about 48 hours including any time period or time period ranges falling within these values. In step 1030, the mixture is then cast and dried to form the SPE of the present invention. In an embodiment, the mixture is cast on Teflon. In an embodiment, the mixture is cast on a Teflon disc. In an embodiment, the cast is dried in temperature of about 20°C to about 99°C such as about 20°C, about 25°C, about 30°C, about 35°C, about 40°C, about 45°C, about 50°C, about 55°C, about 60°C, about 65°C, about 70°C, about 75°C, about 80°C, about 85°C, about 90°C, about 95°C or about 99°C including any temperature or temperature ranges falling within these values for more than about 1 days to about 14 days such as more than about 1 day, about 2 days, about 3 days, about 4 days, about 5 days, about 6 days, about 7 days, about 8 days, about 9 days, about 10 days, about 11 days, about 12 days, about 13 days or about 14 days including any days or day ranges falling within these values. Next, in step 1040, the SPE of the present invention are then placed in a vacuum oven at more than about 20°C to about 50°C such as more than about 20°C, about 25°C, about 30°C, about 35°C, about 40°C, about 45°C or about 50°C or any temperature or temperature ranges falling within these values for about more than about 24h to about 72 h such as more than about 24 h, about 28 h, about 32 h, about 36 h, about 40 h, about 44 h, about 48 h, about 52 h, about 56 h, about 60 h, about 64 h, about 68 h or about 72 h including any hours or hour ranges falling within these values. In an embodiment, the SPE of the present invention may be stored in an argon filled box.

[0080] Examples Experimental Section

[0081] Materials: The recombinant spider silks (MAI and MA2) arc obtained from the Synthetic Biology & Biofabrication Lab at National Taiwan University, founded by Prof. Hsuan-Chen Wu. Both spider silk proteins are composed of a highly repetitive domain flanked by NTDs and CTDs.

[0082] The repetitive region of MAI is designed to follow the sequence (SEQ ID NO 1: GAGAAAAAASGAGQGGYGRQGGQTS)n, while that of MA2 is designed to follow the sequence (SEQ ID NO. 2: GPGGYGPGQQGPSGPAAAAAAGPGGYGPGQQTS)n. Polyethylene oxide (PEO, Mn = 400,000 g mol-1), l,l,l,3,3,3-hexafluoro-2-propanol (HFIP) and bis(trifluoromethane)sulfonimide lithium salt (LiTFSI, 99.0 %) were all purchased from Sigma- Aldrich. The PEO and HFIP were stored in a dry box, and the LiTFSI was stored in an argon-filled glove box that was maintained at < 0.1 ppm O2 and H2O. CR2032 coin cell components (cases, springs, and stainless- steel spacers) were purchased from UBIQ Technology Co., Ltd. 2-mil thick Kapton tape was purchased from Tape Masters. Sodium nitrate (NaNOv 99.5 %), graphite (<20 pm), potassium permanganate (KMnO4, 99.0 %), hydrogen peroxide solution (H2O2, 30 %), and hydrochloric acid (HC1, 37 %) were all sourced from Sigma- Aldrich. Concentrated sulfuric acid (H2SO4, 98 %) was obtained from J.T Baker. All chemicals and items were used as received unless otherwise stated.

[0083] Preparation of P / MAl-x and P / MA2-X Membranes: The P / MA2-X membranes were fabricated using the solvent casting technique. First, PEO was dissolved in HFIP to prepare a PEO solution. MA2 was then introduced into the PEO solution in varying mass ratios (x = 10 %, 25 %, 50 %, 75 %, and 90 %). After stirring for one day, the mixture was spread onto a polytetrafluoroethylene (PTFE) Petri dish. It was dried at room temperature for 1 day and subsequently stored in a vacuum desiccator for further use.

[0084] Preparation of Composite Solid Electrolytes: The P / Li / MA2-x SPE membranes were fabricated using the solvent casting method. First of all, a lithium salt solution was prepared by dissolving the specified amount of LiTFSI in HFIP. Subsequently, MA2 with different mass ratios (x = 10 %, 15 %, 20 %, 25 %, and 35 %) was added into the lithium salt solution. After complete dissolution of MA2, PEO was dissolved in the resulting solution. The molar ratio of [PEO] / [Li] was set at 15:1. Following stirring, the mixture was poured onto a polytetrafluoroethylene (PTFE) Petri dish. It was then dried at 25 °C for 48 hours and subsequently vacuum-dried at 60 °C for 24 hours. After that, the P / Li / MA2-x SPE films with a thickness of approximately 0.2 mm were prepared. These electrolyte membranes were further dried in an argon-filled glove box with O2 and H2O content less than 0.1 ppm for 24 hours prior to measurement and characterization. In the end, the prepared SPE membranes were cut into 18 mm diameter disks for subsequent testing and characterization.

[0085] Preparation of Cathode: The lithium iron phosphate cathode slurry was prepared using NMP as a solvent by mixing LFP, Super P carbon, and PVDF in a ratio of 80:10:10 %. The cathode slurry was cast onto the aluminum foil using a COATMASTER 510, then dried at 100 °C immediately, followed by further drying in a vacuum oven at 80 °C for 24 hours. The LFP composite cathode was prepared and stored in an argon-filled glove box. The thickness of the dry cathodes was approximately 0.1 mm with a mass load of about 2.3 mg cm-2.

[0086] Coin Cell Preparation: Samples were prepared within CR2032 coin cells within an Ar glovebox. All components of the coin cells were crafted from stainless steel and procured from UBIQ Technology Co., Ltd. The preparation of the samples involved layering SPE between stainless steel discs with Kapton tape acting as a spacer. Coin cell components for evaluating ionic conductivity were arranged sequentially: bottom case / disc / samples / disc / spring / top case. Those for testing plating / stripping underwent assembly in this order: bottom case / disc / lithium sheet / samples / lithium sheet / disc / spring / top case. Similarly, coin cell components for assessing cycling performance were organized in this sequence: bottom case / disc / LFP cathode / samples / metallic lithium / disc / spring / top case. To hermetically seal the coin cell, a UBIQ Technology Co., Ltd. C2000-A crimper was employed.

[0087] CP / MAS 13C-NMR: All spectra were acquired on a wide-bore 14.1-T Bruker Advance III spectrometer. Larmor frequencies for1H,13C and15N are 600.21, 150.92 and 60.82 MHz, respectively.13C CP / MAS NMR spectra were acquired with a 2.5 mm magic-angle-spinning (MAS) double-resonance probe head and the sample spinning rate was 21 kHz. The contact time for the cross-polarization (CP) scheme was 2 ms. The ’H TPPM decoupling with the rf field strength of 100 kHz was adopted during the acquisition. The recycle delay was 3 s. ATR-FTIR: IR spectra were obtained with a JASCO FT7IR-4600 spectrometer equipped with an ATR PRO450-S sampling module. All measurements were conducted in air by scanning from 500 cm'1to 4000 cm-1with a total of 32 scans. To ensure sufficient contact, the samples were clamped down onto the diamond ATR crystal.

[0088] SAXS / WAXS: The characteristics of samples related to microstructure were examined using SAXS and WAXS measurements. The SAXS and WAXS experiments were conducted at the beamline BL23A in the National Synchrotron Radiation Research Center (NSRRC). All samples were prepared in an argon-filled glovebox and sealed in 9 cm diameter petri dishes. The openings of the petri dishes were then stored in a desiccator. Spectra for all samples were recorded under ambient conditions with a 5-minute exposure time. The 2D diffraction data was analyzed using XSACT software to obtain plots of scattering intensity versus scattering vector q.

[0089] HAXPES: In the study, elemental composition measurements of the protein samples were taken on a ULVAC-PHI. The setup is equipped with a dual scanning X-ray source consisting of a Cr Koc X-ray source (5.4 KeV) and an Al Koc X-ray source (1.4 KeV). The binding energy scale was calibrated to 284.3 eV based on the prominent C is peak.

[0090] Tensile Testing: All tensile specimens were cut into the shape of dog bones. The tensile tests of the samples were conducted on a universal testing machine (JSV-H1000) at a tensile rate of 10 mm / min at room temperature 25 °C and relative humidity of 66 % in this study. The thickness and width of the tensile specimens were about 0.5 mm and 5 mm, respectively. The length of the sample between the two manual grippers of the tensile testing machine was 20 mm.

[0091] TGA: The thermal stability of the samples was investigated by TGA using a TA Instruments Q50 with a heating rate of 10 °C / min in a nitrogen atmosphere.

[0092] DSC: Samples weighing between 5 and 8 mg were enclosed in aluminum pans within a glovebox. A TA Instrument Discovery DSC 25 was used to take all measurements. Experiments were performed using a hcat-cool-hcat profile with temperatures ranging from -80 °C to 200 °C at a heating rate of 10 °C min-1. The glass transition temperature (Tg) for each sample was extracted from analysis of the second heating curves using the midpoint at half height method. The crystallinity of samples was calculated by using the following calculation:

[0093] Zc = T7 ^ X 100 %

[0094] ZlrtpEO where Hnirepresents the corresponding enthalpy of the melting, and AHPE0is the ideal melting enthalpy of 100 % crystallization of PEO, which is 203 J g-1.

[0095] Rheology: Rheology measurements were taken using a TA Instruments DHR-2 rheometer with parallel plate geometries. Samples were pressed into a circular geometry inside an argon-filled glove box and then loaded onto the rheometer. A sample thickness of about 1 mm was used for all samples. Frequency sweeps were conducted by heating from 30 °C to 100 °C and then cooling back to 30 °C at a rate of 5 °C / min with an applied strain of 0.1 %, using 8 mm parallel plates, and measuring in a frequency range from 10 to 0.01 Hz. All measurements were maintained at the specified temperature for at least 1 hour before conducting the frequency sweep, allowing the material to reach a steady state.

[0096] SEM: The morphology of the PEO / MA2 blend membranes was investigated using a scanning electron microscope (SEM, JEOL JSM-IT100), and the morphology of the SPEs was examined with a JOEL JSM-6700F at a voltage of 10 kV and a current of 10 mA.

[0097] POM: The POM model used in this experiment was the OLYMPUS BX53M.

[0098] Adhesion Test: The adhesion strength was measured using a force gauge (MET-DFG5). Solid polymer electrolytes were cut into 1 cm2squares and sandwiched between two identical substrates. The lap shear testing employed a constant tensile speed of 20 mm / min, with the maximum force recorded to calculate the adhesion strength by dividing it by the bonded area. All measurements were conducted in a glove box filled with Ar (O2 < 0.1 ppm, H2O < 0.1 ppm).

[0099] Electrochemical Measurements:

[0100] Ionic Conductivity: The electrochemical impedance spectrum was measured using the Biologic SP-50e electrochemical workstation, applying an oscillation voltage of 10 mV over a frequency range of 1 MHz to 1 Hz and at temperatures ranging from 30 °C to 80 °C. The electrolyte film was placed between two stainless steel blocking electrodes, each with a diameter of 16 mm. The data collected were then used to calculate ionic conductivity. To reduce interfacial impedance between the electrolyte and the stainless steel and minimize measurement errors, the assembled SSISPEISS cell was activated at 80 °C for 48 hours. Additionally, samples were allowed to stabilize at each test temperature for at least 2 hours before recording the impedance response. The ionic conductivity was calculated according to the following equation:

[0101] L o = -

[0102] R x S where L represents the thickness of the electrolyte film, R denotes the resistance of the bulk electrolyte, and S indicates the contact area between the electrode and the electrolyte.

[0103] LSV: The electrochemical stability windows of PEO-based SPE incorporated with different contents of MA2 were studied by linear scanning voltammetry on Biologic SP-50e electrochemical workstation. The LSV test was conducted over a voltage range of 3.0 to 6.0 V (vs. Li+ / Li) with a scanning rate of 1 mV s-1to examine the electrochemical stability of the electrolytes at 80 °C. The SSISPEILi battery assembly took place within the glove box.

[0104] Transference Number: Lithium ion transference numbers for different solid electrolytes were determined by combining AC impedance and DC polarization measurements at 60 °C, using a symmetric battery with a voltage of 10 mV. The symmetric battery was subjected to DC polarization at this voltage. The following equation was utilized to calculate the transference number: S(AV - IORO)

[0105] LiI0(AV — ISRS) where l0and lswere the initial and steady-state currents flowing through the battery, respectively. Roand Rswere the resistance values before and after polarization, respectively, obtained from the impedance spectrum of the battery in the frequency range of 10 MHz to 0.1 Hz, with an oscillating voltage of 10 mV. Charge-Discharge Performance of Lithium-Ion Batteries: All solid-state lithium-ion batteries (2032 type) were assembled in an argon-fillcd glove box with oxygen and H2O content of less than 0.1 ppm. LFP was utilized as the cathode, and metallic lithium was used as the anode. The charge and discharge performance of LFPISPEILi batteries was carried out using a battery tesing system (Neware CT-4008) with a voltage range from 2.5 to 4.0 V at 60 °C. Prior to cycle testing, the battery was heated for 24 hours. This heating and activation process improved the contact between the electrode and the electrolyte, leading to a reduction in interfacial resistance between the electrodes and the electrolyte membrane.

[0106] Result and Discussion

[0107] Blending PEO with natural spider silk significantly enhances its mechanical properties and reduces crystallinity, making the PEO / spider silk composite ideal for SPE applications. To explore the impact of different spider silk structures, we incorporated two major ampullate spidroin proteins, MAI and MA2, into PEO-based SPE. Both proteins were synthesized using E. coli as a heterologous host. The latter has less crystallinity, indicating that MA2 is softer than MAI.

[0108] FIG. 5a and 5b and FIGs. 6a and 6b show the mechanical property measurements of P / MA2 blends, including tensile strength, elongation at break, and toughness from stress-strain curves. The blends range from pure PEO to pure MA2, with various MA2 percentages (10 % to 90 %). Pure PEO exhibited a tensile strain of 430.1 %, tensile strength of 8.7 MPa, and toughness of 30 MPa, while pure MA2 showed a tensile strain of 3 %, tensile strength of 44 MPa, and toughness of 5 MPa. As MA2 content increased, tensile strength improved. At 25 % MA2, the blend achieved the highest tensile strain (1215 %) and toughness (250 MPa). FIG. 8a and 8b and FIG. 9a and 9b also highlight the enhanced mechanical properties of P / MA1 at different ratios.

[0109] TGA measurements of P / MA2 blends at different weight percentages are shown in FIG. 15a. Pure MA2 displays four weight loss steps between 100 °C and 800 °C, with losses at 160-250 °C and 250-370 °C due to peptide bond cleavage and side chain degradation, and a third and final loss from 370 °C to 800 °C related to the breakdown of covalent bonds in the [3-sheet structure.36Pure PEO shows decomposition between 300 °C and 440 °C, with major mass loss around 400 °C, consistent with the literature.37The Tas% of pure MA2 is 197 °C, indicating good thermal stability, while pure PEO's T s% is 359 °C. Notably, adding 10 % PEO increases MA2’s Td5% to 265.4 °C, significantly enhancing its thermal stability. FIG. 20a shows similar measurements for P / MA1 blends, where pure MAI has a Td5% of 259 °C, higher than MA2 due to its greater crystallinity. Overall, thermal stability increases with higher PEO content in both blends.

[0110] ATR-FTIR spectroscopy was used to investigate the miscibility and interaction between MA2 and PEO. FIG. 15b displays the FTIR spectrum, clearly indicating the characteristic absorption peaks of MA2 and PEO. The peak at 1100 cm-1corresponds to C-O-C bonds in PEO, and a slight shift to lower frequencies in P / MA2 blends indicates increased hydrogen bonding between the C-O-C groups of PEO and the N-H groups of MA2.4This interaction reduces electron density on the C- O bond, causing a red shift from 1110 cm-1to about 1088 cm-1.38FTIR measurements provide a compelling explanation for the observed enhancement in mechanical properties resulting from blending MA2 with PEO. Additionally, this elucidates how MA2 can effectively hinder the formation of PEO crystallization. This occurs because intermolecular interactions make it difficult for PEO chains to rearrange and form crystalline structures.

[0111] The crystallization behavior of P / MA2 blends was examined using SAXS measurements. FIG. 15c shows the SAXS profiles, featuring a primary scattering peak and higher-order peaks in a 1:2:3 ratio, indicative of a crystalline lamellar structure in the PEO domains.39As the MA2 proportion increases, the scattering peaks at q = 0.023 and 0.046 exhibit a slight decrease in q-values, suggesting an increase in the long-period of PEO due to MA2's good miscibility with the PEO amorphous region, which expands the distance between PEO lamellae. A similar trend is observed in P / MA1 blends (FIG. 20b), indicating comparable miscibility of MAI with PEO. Notably, when MA2 ratios reach 75 % and 90 %, the scattering peaks become featureless, reflecting a lower degree of crystallinity as MA2 restricts PEO crystallization. The absence of discernible peaks also suggests a lack of coherently stacked PEO lamellae at high MA2 content, as spider silk's strong compatibility with the amorphous region increases spacing between PEO lamellae, preventing orderly stacking. In summary, SAXS measurements confirm MA2's good miscibility with PEO, leading to an expanded long-period.

[0112] WAXS results in FIG. 15d indicate significantly lower crystallinity in P / MA2 films with high MA2 content. The two prominent peaks at 13 and 16 nm-1correspond to the (120) and (112) / (032) planes of a monoclinic unit cell, with interplanar spacings of 0.46 and 0.38 nm, respectively.40The monoclinic unit cell in PEO contains four helical chains of seven monomeric units, forming a 7 helix that aligns with a gauchc-trans-trans sequence of bond rotations.39, 41, 42The helix is oriented along the

[0001] c-axis, with chain folding occurring along the (120) planes. The (120) reflections provide insights into interchain separations and configurations, while (112) reflections reveal structural information along the c-axis related to helicity.43As MA2 content increases, the intensity of the (112) peak gradually weakens, indicating thinner PEO lamellae. Notably, the diffraction peaks of PEO crystallinity vanish at 90 % MA2 due to interactions that suppress PEO crystalline formation.

[0113] FIG. 15e shows a typical one-dimensional electron density correlation function profiles. The results from this method closely match those calculated from the q-value of the SAXS profile of FIG. 15c. Looking first at neat PEO membrane, the long-period value and the thickness of the crystalline part (Lc) were 26.6 nm and 6.7 nm, respectively. As the MA2 mass percentage increased to 75 %, Lcdecreased from 6.7 nm to 3.3 nm, indicating that MA2 facilitates the formation of thinner lamellae by stabilizing PEO's surface energy through hydrogen bonding. Meanwhile, Lpincreased from 26.6 nm to 32.4 nm. The thickness of the amorphous regions (La), calculated from Lpand Lc, rose from 19.9 nm to 29.1 nm, demonstrating good miscibility between MA2 and the PEO amorphous region, which expands the distance between lamellar’ crystalline parts. Besides, the result of thinner lamellae is consistent with the WAXS measurements.

[0114] According to previous research, spider silk protein is believed to be a promising material for SPE applications. Based on this, LiTFSI is incorporated into PEO / MA2 composites to fabricate P / Li / MA2 SPEs. In the next section, a series of characterizations of the SPEs was conducted to explore the detailed mechanism.

[0115] FIG.16a presents the mechanical properties of P / Li / MA2 SPEs obtained through tensile testing, with parameters such as tensile strength, elongation at break, and toughness illustrated in FIG. 13b, 17a and 17b. Compared to pure PEO, the mechanical properties of P / Li SPE significantly decline, exhibiting a tensile strain of only 171.8 %, a tensile strength of 1 MPa, and toughness of 1.6 MPa. This reduction is attributed to decreased PEO crystallization due to strong miscibility between the lithium salt and PEO, as Li+cations coordinate with the lone-pair electrons of oxygen in the EO segment. Incorporating MA2 markedly improves the mechanical properties, with the P / Li / MA2- 20 SPE achieving a toughness of 16.2 MPa. While tensile stress and modulus increase with higher MA2 ratios, elongation at break decreases. Notably, as the P / MA2 ratio shifts from 80 / 20 to 65 / 35, tensile strain drops from 461 % to approximately 285 %. Thus, while MA2 enhances the strength of PEO-based SPEs, its higher proportion may decrease their elasticity beyond 35 %.

[0116] The thermal stability of electrolytes was also examined to ensure that they can function stably at high temperatures. From FIG. 17a, it can clearly be observed that P / Li / MA2 SPEs exhibit remarkable thermal stability, ensuring that thermal decomposition will not occur when the batteries operate under high-temperature conditions. Measurements were also taken for MAI -blended PEO- based SPEs, as shown in FIG. 17b.

[0117] FTIR analysis was performed to investigate the interactions among PEO, MA2, and LiTFSI. FIG.21a shows distinct absorption peaks for PEO and MA2. Amide I, II, and III bands were observed in the 1590-1700 cm-1, 1460-1590 cm-1, and 1200-1400 cm-1ranges, respectively. The C=O and C-O-C peaks of PEO appeared at 1700 cm-1and 1080 cm-1, with the C-O-C band in neat PEO-based SPE shifting to lower frequencies due to Li+coordination. A redshift in the C-O-C peak, increasing with MA2 content, indicated enhanced hydrogen bonding between PEO and MA2’s N-H group. These shifts confirm interactions among PEO, lithium ions, and MA2. The vibration bands at 1359 cm-1and 1342 cm-1correspond to the CH2 wagging motion in the trans conformation of EO segments, indicating PEO's crystalline state. The 1349 cm-1peak is linked to the wagging vibrations of EO methylene in the gauche conformation.44In pure PEO, the 1359 cm-1and 1342 cm-1bands are prominent due to its high crystallinity. However, blending lithium salt and MA2 with PEO replaces this doublet with a single 1349 cm-1band, disrupting PEO's crystallinity. In PEO-based SPEs, the trans conformation bands are slightly visible, but they nearly disappear when MA2 is added, suggesting a shift from trans to gauche conformation and a transition to a more amorphous structure. These changes indicate that the addition of LiTFSI and MA2 decreases PEO crystallinity and increases amorphous content.

[0118] The thermal properties of SPEs are critical for LIB applications. FIG.21b presents the DSC profiles of pure PEO and PEO-based SPEs with varying MA2 content, ranging from -60 °C to 100 °C. Table 2 provides detailed information calculated from the DSC curves.

[0119] Table 2 The outline of thermodynamic parameters for MA2-blended PEO-based SPEs

[0120] Sample Tg(°C) Tc(°C) P / Li / MA2-35 -41.56 13.44 22.35 39.49 22.80 11.23

[0121] P / Li / MA2-25 -42.95 15.61 27.43 42.84 27.51 12.55

[0122] P / Li / MA2-20 -43.48 17.52 30.38 43.92 34.11 16.80

[0123] P / Li / MA2-15 -44.22 12.61 36.46 45.75 40.22 19.81

[0124] P / Li / MA2-10 -44.26 3.76 19.30 48.52 45.34 22.33

[0125] PEO / Li -40.54 -1.44 12.33 49.64 65.04 32.04

[0126] Pure PEO -53.10 70.89 180.76 89.04

[0127] As shown, pure PEO has a Tmof 70.89 °C, while the P / Li SPE shows a significantly lower Tmof 49.64 °C, indicating that the addition of LiTFSI reduces the melting point due to interactions with PEO. Increasing MA2 content further decreases Tmand crystallinity, as hydrogen bonding between PEO and MA2 hinders PEO crystallization and promotes amorphous formation. This finding supports the observation that a mixing content of MA2 exceeding 15 % makes the Tgof the composite more easily detectable. Additionally, the Tcof the SPEs rises with more MA2, which impedes PEO's cold crystallization process. As MA2 content increases, the heat of crystallization (AHC) and melting (AHm) values converge, indicating reduced PEO crystallization during cooling. The recrystallization peak observed during heating suggests that PEO does not crystallize during cooling, implying that PEO chains cannot rearrange in an orderly manner due to hindered crystallization. Because MA2 can interact with PEO, the movement of PEO chains is hindered, preventing crystallization. When MA2 content reaches 25 % or more, the integrated value of the PEO recrystallization peak approaches that of the melting peak, demonstrating MA2's effectiveness in inhibiting PEO recrystallization— In addition, the crystallization behavior of P / Li / MAl SPE is also discussed in Figure S15 and Table 3. It was found that MA2 has a better ability to disrupt and suppress the crystallinity of PEO than MAI.

[0128] Table 3 The outline of thermodynamic parameters for MAl-blended PEO-based SPEs

[0129] Sample Tg(°C) Tc(°C) AFC(J / g) Tm(°C) AHm(J / g)Xc(%) P / Li / MAL30 -42.25 18.56 35.90 40.62 35.71 17.59

[0130] P / Li / MAl-20 -43.81 6.24 41.48 43.85 49.13 24.20

[0131] P / Li / MAl-10 -41.07 1.85 10.08 46.51 60.90 30.00

[0132] PEO / Li -40.54 -1.44 12.33 49.64 65.04 32.04

[0133] Pure PEO -53.10 70.89 180.76 89.04

[0134] DSC was further used to observe changes in crystallinity over time, demonstrating the suppression of recrystallization by MA2 (FIG. 16c). The initial crystallinity of neat PEO-based SPE (32 %) is much higher than those with MA2. As MA2 content increases to 35 %, the crystallinity decreases from 32 % to 11 %, indicating that MA2 effectively disrupts PEG crystallinity. While neat PEO- based SPE crystallinity rises rapidly to 58.5 % after 2 months, SPEs with MA2 exhibit a slower increase and maintain relatively low crystallinity after 2 months. This slower crystallization with higher MA2 ratios indicates its efficiency in preventing PEO recrystallization.

[0135] The reduction in PEO crystallinity after incorporating MA2 is evident in WAXS measurements (FIG. 16d), where two strong peaks at 13 and 16 nm-1, corresponding to the (120) and (112) / (032) planes, are observed. As MA2 content increases, the intensity of these crystalline peaks significantly decreases, indicating a transition to a more amorphous structure, which enhances lithium ion transfer. A similar trend is seen in P / Li / MAl SPEs (FIG. 20d), with crystallization behavior also examined using SAXS (FIG. 21a and FIG. 21b).

[0136] The effect of PEO crystallinity with MA2 addition (P / Li vs. P / Li / MA2-20) was investigated using POM FIG. 12, with full data in Figure S19. For P / Li SPE, well-dispersed spherulites (-100 pm) were observed, while black regions indicated amorphous areas. It is clear that incorporating MA2 further diminished the amount and size of microcrystals, as the interaction between MA2 and PEO hindered EO segment crystallization. POM images show that crystallinity is dramatically reduced after incorporating MA2 into P / Li SPE.

[0137] Poor solid-solid contact at the SSEs / electrodes interface is a key challenge in solid-state electrolytes. The P / Li / MA2 SPEs, with high adhesiveness, attach to electrodes like tape, creating strong interfacial adhesion that reduces impedance and enhances Li+transfer. To study the impact of recombinant spider silk on adhesion, PEO-based SPEs with 20 % and 35 % MA2 were tested using lap shear testing on various substrates (anode, cathode, aluminum, copper). The P / Li / MA2 SPEs showed significantly greater adhesion than neat PEO, with bonding strength increasing with MA2 content (FIG. 19). This is attributed to reduced PEO crystallinity, giving the SPEs gel-like properties, and the numerous hydrogen bonds in MA2.

[0138] FIG. 3 shows the ionic conductivity of various electrolytes between 30 and 80 °C. The addition of MA2 significantly enhances the ionic conductivity of electrolytes, aligning with previous characterizations. The P / Li / MA2-20 electrolyte exhibits the highest conductivity among these electrolytes, measuring 3.0 x 10-4S cm-1at 30 °C and 2.7 x 10-3S cm-1at 80 °C. However, conductivity sharply declines beyond a 25 % MA2 ratio, with the P / Li / MA2-35 SPE showing much lower values than other ratios. These results indicate that MA2 enhances ionic conductivity by reducing PEO crystallinity and supporting Li+mobility through hard amide |3-shcct nanocrystals. Despite MA2's benefits, PEO content remains crucial for ionic transfer, with conductivity dropping when MA2 exceeds the critical value. Neat PEO-based SPE shows a two- stage linear conductivity feature with an inflection point at 50 °C, while MA2-blended electrolytes lack this inflection due to their low crystallinity nature. At low temperatures, MA2-blended SPEs maintain high conductivity without an inflection point, confirming that reduced PEO crystallinity from MA2 interaction enhances ionic conductivity. Additionally, the ionic conductivity of P / Li / MAl SPEs was also measured (FIG. 7), revealing that P / Li / MA2 SPEs have higher ionic conductivity than P / Li / MAl SPEs, supporting the expectation that MA2 is more effective at suppressing PEO crystallinity than MAI.

[0139] To investigate the electrochemical stability window (ESW), LilSPEISS batteries were assembled to study the voltage stability of the SPEs. As shown in FIG. 18a, the oxidation current for neat PEO-based SPE remains nearly zero until reaching 5.0 V (vs. Li / Li+), after which it increases due to PEO decomposition.4This indicates that neat PEO-based SPE has favorable electrochemical stability between 3.0 and 5.0 V, making it suitable for LIB applications. Notably, the ESW increases slightly from 5.0 V to approximately 5.3 V (vs. Li / Li+) with MA2 addition, suggesting improved stability for the polymer blend electrolytes. Additionally, P / Li / MA2 SPEs demonstrate excellent electrochemical stability at 80 °C, reducing risks in high-tcmpcraturc environments and enabling use in high-potential LIBs. The lithium-ion transference number (tj) of the SPE was estimated using chronoamperometry (CA), with metallic lithium as both the working and counter electrodes. FIG. 18b shows the CA profile, while the inset displays EIS curves from 1 Hz to 1 MHz of the symmetric cell before and after the DC polarization test. The calculated t value for the P / Li / MA2-20 SPE is 0.37 at 60 °C, which is satisfactory compared to literature values and promising for future SPE applications. In contrast, the of the PEO-LiTFSI electrolyte is approximately 0.2, according to the previous report.45, 46The higher t h is likely due to the rigid amide |3-shcct nanocrystals in spider silk, which enhance Li+ion mobility by coordinating with TFSF.46

[0140] The long-term stability of the LilP / Li / MA2-20ILi symmetric cell was evaluated to assess electrolyte performance. As shown in FIG. 18c, the cell cycled stably for nearly 4000 hours at 0.2 mA cm-2and 60 °C without short circuit. The initial polarization voltage was 96 mV, increasing to 100 mV after 4000 hours. Plating / stripping tests confirmed the P / Li / MA-20 SPE membrane's high compatibility with lithium metal and strong resistance to dendrite penetration and formation. The cycling performance of ASSLIBs was evaluated at 0.2 C and 60 °C, as shown in FIG. 18d. The neat PEO-based SPE exhibited low initial charge capacity (144.8 mAh g-1) due to high crystallinity, poor interface stability, and low ionic conductivity. The charge capacity of the neat PEO-based SPE dropped after the 30th cycle, remaining at only 17.5 mAh g-1after 150 cycles, primarily due to poor mechanical properties and electrode-electrolyte incompatibility. In contrast, PEO-based SPEs blended with 15 %, 20 %, and 25 % MA2 showed excellent capacity, stability, and near 100 % coulombic efficiency. The LFPIP / Li / MA2-20ILi cell exhibited the best performance, with an initial capacity of 168 mAh g-1and 97.2 % capacity retention after 150 cycles. Furthermore, the battery operated at 25 °C was tested, showing an initial charge capacity of 134.8 mAh g-1, which dropped to 126.6 mAh g_|after 70 cycles, indicating good performance at room temperature (FlG.23e). In summary, blending MA2 with PEO-based electrolytes enhances ionic conductivity, mechanical strength, and interface stability, demonstrating potential for practical applications in ASSLIBs.

[0141] FIG. 18e shows the charge and discharge curves of the LFPIP / Li / MA2-20ILi coin cell at 0.2 C for the 1st, 5th, 10th, 20th, 50th, 100th, and 150th cycles. The curves display typical voltage plateaus of 3.5 V (charge) and 3.4 V (discharge), characteristic of LilLiFePO4 cells.47The chargc / dischargc profiles up to the 100th cycle overlap well, with minimal overpotential (approximately 0.084 V) that remains stable, indicating strong cathode stability. After 150 cycles, the polarization potential slightly increases to 0. 15 V, possibly due to cathode exfoliation and loss of interfacial contact.48, 49These results confirm good electrochemical performance at 60 °C.

[0142] To assess the rate performance, charge and discharge tests were conducted on the LFPISPEILi battery at current densities of 0.05 to 2.0 C. As shown in FIG.14, the discharge capacity reaches 172 mAh g-1at low current density, decreasing to 100.8 mAh g-1at 2.0 C. When returned to 0.1 C, the capacity rebounds to 163.5 mAh g-1, demonstrating high stability. The charge-discharge potential gap widens from 0.07 to 0.48 V as the rate increases (FIG.14). All of the above highlights the excellent rate performance and promising application of MA2-blended PEO-based SPE for ASSLIBs.

[0143] Conclusions

[0144] The P / Li / MA2-20 SPE prepared in this study exhibits enhanced mechanical properties, improved interface contact, and remarkable ionic conductivity. The P / Li / MA2-20 electrolyte can withstand a maximum stress of 2.96 MPa, and its elongation at break can reach 544.7 %. Its excellent mechanical performance provides the electrolyte with ultra-durability against lithium dendrite formation during charge-discharge processes. The abundant hydrogen bonds within spider silk provide the electrolyte with strong adhesion, ensuring close interface contact with the electrodes. This leads to reduced interface impedance and promotes Li+transfer. Furthermore, the addition of MaSp2 can effectively hinder the crystallization of PEG and increase the amorphous region, boosting the mobility of lithium ions. The ionic conductivity of the P / Li / MA2-20 electrolyte can reach 3.0 x 10-4S cm-1at 30 °C, which is much higher than that of neat PEO-based SPE. The excellent mechanical strength, intimate interface, and high ionic conductivity result in superior electrochemical performance and cycling stability. The LilP / Li / MA2-20ILi symmetric battery could be cycled at a current density of 0.2 mA cm-2for 4000 hours with a low overpotential, indicating excellent performance in inhibiting lithium dendrites. Moreover, the LilP / Li / MA2- 20ILFP cell exhibits outstanding cycling stability and rate properties, with an initial charge capacity of 168 mAh g-1at 0.2 C and 97 % capacity retention after 150 cycles. These results demonstrate that bio-cnginccring spider silk is a promising material with great potential for practical applications in all- solid- state lithium-ion batteries.

[0145] Acknowledgments This work received support from the Asian Office of Aerospace Research and Development (AO ARD FA2386-22- 1-4031) and the Ministry of Science and Technology, Taiwan (MOST 112- 2221-E-002-023-MY3, S.-H. T.). I also acknowledge Mr. Shing-Jong Huang and Mr. Han-Pang Chen from the Instrument Center, College of Science, National Taiwan University / National Science and Technology Council, for providing assistance with13C CPMAS NMR and XPS measurements, respectively.

[0146] References each of which is hereby incorporated in its entirety

[0147] 1. Chen, Y.; Wen, K.; Chen, T.; Zhang, X.; Armand, M.; Chen, S., Recent progress in allsolid- state lithium batteries: The emerging strategies for advanced electrolytes and their interfaces. Energy Storage Materials 2020, 31, 401-433.

[0148] 2. Ding, B.; Wang, J.; Fan, Z.; Chen, S.; Lin, Q.; Lu, X.; Dou, H.; Kumar Nanjundan, A.; Yushin, G.; Zhang, X.; Yamauchi, Y, Solid-state lithium-sulfur batteries: Advances, challenges and perspectives. Materials Today 2020, 40, 114-131.

[0149] 3. Yue, L.; Ma, J.; Zhang, J.; Zhao, J.; Dong, S.; Liu, Z.; Cui, G.; Chen, L., All solid-state polymer electrolytes for high-performance lithium ion batteries. Energy Storage Materials 2016, 5, 139-164.

[0150] 4. Tao, C.; Gao, M.-H.; Yin, B.-H.; Li, B.; Huang, Y.-P.; Xu, G ; Bao, J.-J., A promising TPU / PEO blend polymer electrolyte for all- solid- state lithium ion batteries. Electrochimica Acta 2017, 257, 31-39.

[0151] 5. Li, J.; Zhu, K.; Wang, J.; Yan, K.; Liu, J.; Yao, Z.; Xu, Y, Optimisation of conductivity of PEO / PVDF-based solid polymer electrolytes in all-solid-state Li-ion batteries. Materials Technology 2020, 37 (4), 240-247.

[0152] 6. Zhu, L.; Li, J.; Jia, Y; Zhu, P; Jing, M.; Yao, S.; Shen, X.; Li, S.; Tu, F., Toward high performance solid-state lithium-ion battery with a promising PEO / PPC blend solid polymer electrolyte. International Journal of Energy Research 2020, 44 (13), 10168-10178.

[0153] 7. Olmedo-Martinez, J. L.; Pastorio, M.; Gabirondo, E.; Lorenzetti, A.; Sardon, H.; Mecerreyes, D.; Muller, A. J., Poly ether Single and Double Crystalline Blends and the Effect of Lithium Salt on Their Crystallinity and Ionic Conductivity. Polymers (Basel) 2021, 13 (13). 8. Olmedo-Martinez, J. L.; Porcarelli, L.; Guzman-Gonzalez, G ; Calafel, I.; Forsyth, M.; Mecerreyes, D.; Muller, A. J., Ternary Poly(ethylene oxide) / Poly(l,l-lactidc) PEO / PLA Blends as High-Temperature Solid Polymer Electrolytes for Lithium Batteries. ACS Applied Polymer Materials 2021, 3 (12), 6326-6337.

[0154] 9. Zhaoyin Wen, T. I., Yoshiaki Ichikawa, Masataka Kubo, Osamu Yamamoto, Blend-based polymer electrolytes of poly (ethylene oxide) and hyperbranched poly[bis(triethylene glycol)benzoate] with terminal acetyl groups. Solid State Ionics 2000, 134, 281-289.

[0155] 10. Mei, X.; Huang, Y; Chen, S.; Tang, M.; Li, J.; Bo, S.-H.; Guo, Y, Improving Ion Conductivity in Polymer Blend Electrolytes by Tuning Microdynamics and Interfaces. ACS Applied Polymer Materials 2023, 5 (11), 9225-9235.

[0156] 11. Xin, C.; Wen, K.; Guan, S.; Xue, C.; Wu, X.; Li, L.; Nan, C.-W, A Cross-Linked Poly(Ethylene Oxide)-Based Electrolyte for All-Solid-State Lithium Metal Batteries With Long Cycling Stability. Frontiers in Materials 2022, 9.

[0157] 12. Liang, H. P.; Chen, Z.; Dong, X.; Zinkevich, T.; Indris, S.; Passerini, S.; Bresser, D., Photo-Cross-Linked Single-Ion Conducting Polymer Electrolyte for Lithium-Metal Batteries. Macromol Rapid Commun 2022, 43 (12), e2100820.

[0158] 13. Li, C.; Hu, A.; Zhang, X.; Ni, H.; Fan, J.; Yuan, R.; Zheng, M.; Dong, Q., An intrinsic polymer electrolyte via in situ cross-linked for solid lithium-based batteries with high performance. PNAS Nexus 2023, 2 (9), pgad263.

[0159] 14. Yang, Y; Li, W.; Zhou, N.; Shen, J., Design and Construction of Cross-Linked PEG with the Integration of Helical Polyurethane as an Advanced All-Solid-State Polymer Electrolyte for Lithium Batteries. Journal of Chemical Education 2020, 97 (10), 3758-3765.

[0160] 15. Xinming Qian, N. G., Zhiliang Cheng, Xiurong Yang, Erkang Wang, Shaojun Dong, Plasticizer effect on the ionic conductivity of PEO-based polymer electrolyte. Materials Chemistry and Physics 2002, 74, 98-103.

[0161] 16. LEIRE ZUBIZARRETA, M. G.-A., IUAN CARLOS ESPINOSA, MARTA GARCIA- PELLICER, ALFREDO QUIJANO-LOPEZ, Studying the Properties of PVdF-HFP Based Lithium Polymer Electrolytes Using non-ionic Surfactants as Plasticizers. Materiale Plastice 2021, 58, 237-247. 17. Deb, D.; Bose, P.; Bhattacharya, S., lonanofluid plasticized electrolyte with improved electrical and electrochemical properties for high-performance lithium polymer battery.

[0162] International Journal of Energy Research 2020, 44 (13), 10506-10522.

[0163] 18. Banitaba, S. N.; Semnani, D.; Heydari-Soureshjani, E.; Rezaei, B.; Ensafi, A. A., The effect of concentration and ratio of ethylene carbonate and propylene carbonate plasticizers on characteristics of the electrospun PEO-based electrolytes applicable in lithium-ion batteries. Solid State Ionics 2020, 347.

[0164] 19. Ahmed, H. T; Jalal, V. J.; Tahir, D. A.; Mohamad, A. EL; Abdullah, O. G., Effect of PEG as a plasticizer on the electrical and optical properties of polymer blend electrolyte MC-CH-LiBF4 based films. Results in Physics 2019, 75.

[0165] 20. Kumar, Y; Hashmi, S. A.; Pandey, G. P, Lithium ion transport and ion-polymer interaction in PEO based polymer electrolyte plasticized with ionic liquid. Solid State Ionics 2011, 201 (1), 73-80.

[0166] 21. Srivastava, S.; Schaefer, J. L.; Yang, Z.; Tu, Z.; Archer, L. A., 25th anniversary article: polymer-particle composites: phase stability and applications in electrochemical energy storage. Adv Mater 2014, 26 (2), 201-34.

[0167] 22. Bocharova, V.; Chen, X. C.; Jeong, S. P; Zhou, Z.; Sacci, R. L.; Keum, J. K.; Gainaru, C.; Rahman, M. A.; Sahori, R.; Sun, X.-G.; Cao, P.; Westover, A., Single Ion Conducting Hairy Nanoparticle Additive to Improve Cycling Stability of Solid Polymer Electrolytes. ACS Applied Energy Materials 2023, 6 (15), 8042-8052.

[0168] 23. Chen, Z.; Jia, H.; Yan, S.; Gohy, J.-E, Polymer-coated silica dual functional fillers to improve the performance of poly(ethylene oxide)-based solid electrolytes. Nano Energy 2023, 114.

[0169] 24. Yang, X.; Liu, J.; Pei, N.; Chen, Z.; Li, R.; Fu, L.; Zhang, P; Zhao, J., The Critical Role of Fillers in Composite Polymer Electrolytes for Lithium Battery. Nanomicro Lett 2023, 75 (1), 74.

[0170] 25. Sripada, S.; Reddy, M. C.; Sreekanth, T.; Siripuram, R.; Venkateshwarlu, K., Influence of Nano Filler (ZrO2) on Optical and Thermal Studies of Potassium Doped Polyethylene Oxide Solid Polymer Electrolytes. Materials Science Forum 2022, 1048, 101-109.

[0171] 26. Ma, J.; Chen, B.; Wang, L.; Cui, G., Progress and prospect on failure mechanisms of solid- state lithium batteries. Journal of Power Sources 2018, 392, 94-115. 27. Zheng, Y; Yao, Y; Ou, J.; Li, M.; Luo, D.; Dou, H.; Li, Z.; Amine, K.; Yu, A.; Chen, Z., Arcvicw of composite solid-state electrolytes for lithium batteries: fundamentals, key materials and advanced structures. Chem Soc Rev 2020, 49 (23), 8790-8839.

[0172] 28. Zhang, D.; Xu, X.; Qin, Y; Ji, S.; Huo, Y; Wang, Z.; Liu, Z.; Shen, J.; Liu, J., Recent Progress in Organic-Inorganic Composite Solid Electrolytes for All-Solid-State Lithium Batteries. Chemistry 2020, 26 (8), 1720-1736.

[0173] 29. Lv, N.; Zhang, Q.; Xu, Y; Li, H.; Wei, Z.; Tao, Z ; Wang, Y; Tang, H, PEO-based composite solid electrolyte for lithium battery with enhanced interface structure. Journal of Alloys and Compounds 2023, 938.

[0174] 30. Yang, L.; Wang, Z.; Feng, Y; Tan, R.; Zuo, Y; Gao, R.; Zhao, Y; Han, L.; Wang, Z.; Pan, F., Flexible Composite Solid Electrolyte Facilitating Highly Stable “Soft Contacting” Li- Electrolyte Interface for Solid State Lithium-Ion Batteries. Advanced Energy Materials 2017, 7 (22).

[0175] 31. Jia, Z.; Liu, Y; Li, H.; Xiong, Y; Miao, Y; Liu, Z.; Ren, F., In- situ polymerized PEO- based solid electrolytes contribute better Li metal batteries: Challenges, strategies, and perspectives. Journal of Energy Chemistry 2024, 92, 548-571.

[0176] 32. Deng, C.; Chen, N.; Hou, C.; Liu, H.; Zhou, Z.; Chen, R., Enhancing Interfacial Contact in Solid-State Batteries with a Gradient Composite Solid Electrolyte. Small 2021, 17 (18), e2006578.

[0177] 33. Duan, H.; Yin, Y X.; Shi, Y; Wang, P. F.; Zhang, X. D ; Yang, C. P; Shi, J. L.; Wen, R.; Guo, Y. G.; Wan, L. J., Dendrite-Free Li-Metal Battery Enabled by a Thin Asymmetric Solid Electrolyte with Engineered Layers. J Am Chem Soc 2018, 140 (1), 82-85.

[0178] 34. Cheng, Z.; Pan, H.; Li, C ; Mu, X.; Du, Y; Zhang, F.; Zhang, X.; He, P.; Zhou, H., Anin situsolidifying strategy enabling high-voltage all- solid- state Li-metal batteries operating at room temperature. Journal of Materials Chemistry A 2020, 8 (47), 25217-25225.

[0179] 35. Gao, L.; Sarmad, B.; Li, J.; Cheng, B.; Kang, W.; Deng, N., Application of polyamide 6 microfiber non-woven fabrics in the large-scale production of all-solid-state lithium metal batteries. J Power Sources 2020, 475, 228663.

[0180] 36. Gupta, P.; Kumar, M.; Bhardwaj, N.; Kumar, J. P; Krishnamurthy, C. S.; Nandi, S. K.; Mandal, B. B., Mimicking Form and Function of Native Small Diameter Vascular Conduits Using Mulberry and Non-mulberry Patterned Silk Films. ACS Appl Mater Interfaces 2016, 8 (25), 15874- 88.

[0181] 37. Abels, G.; Bardenhagen, L; Schwenzel, J.; Langer, F., Thermal Stability of Polyethylene Oxide Electrolytes in Lithium Nickel Manganese Cobalt Oxide Based Composite Cathodes. Journal of The Electrochemical Society 2022, 169 (2).

[0182] 38. Emanuele Calabro, S. m., On the hydrogen bond increasing in polyethylene oxide aqueous solution induced by exposure to electromagnetic fields. Physical Chemistry: An Indian Journal 2013, 8 (2), 59-66.

[0183] 39. Samanta, P; V, T.; Singh, S.; Srivastava, R.; Nandan, B.; Liu, C. L.; Chen, H. L., Crystallization behaviour of poly(ethylene oxide) under confinement in the electrospun nanofibers of polystyrene / poly(ethylene oxide) blends. Soft Matter 2016, 12 (23), 5110-20.

[0184] 40. Chen, H.; Chen, X.; Chen, H.; Liu, X.; Li, J.; Luo, J.; He, A.; Han, C. C ; Liu, Y; Xu, S., Molecular Interaction, Chain Conformation, and Rheological Modification during Electrospinning of Hyaluronic Acid Aqueous Solution. Membranes (Basel) 2020, 10 (9).

[0185] 41. Tadokoro, Y. T. a. H., Structural Studies of Polyethers, (-(CH2)m-0-)n. X. Crystal Structure of Poly(ethylene oxide). Macromolecules 1973, 6 (5), 672-675.

[0186] 42. Lei Zhu, S. Z. D. C., Bret H. Calhoun, Qing Ge, Roderic P. Quirk, Edwin L. Thomas, Benjamin S. Hsiao, Fcngji Yeh, and Bernard Lotz, Crystallization Temperature-Dependent Crystal Orientations within Nanoscale Confined Lamellae of a Self- Assembled Crystalline-Amorphous Diblock Copolymer. J. Am. Chem. Soc. 2000, 722, 5957-5967.

[0187] 43. Kwon, O. H.; Ortalan, V.; Zewail, A. H., Macromolecular structural dynamics visualized by pulsed dose control in 4D electron microscopy. Proc Natl Acad Sci USA 2011, 108 (15), 6026- 31.

[0188] 44. Calabro, E.; Magazu, S., On the hydrogen bond increasing in polyethylene oxide aqueous solution induced by exposure to electromagnetic fields. Physical Chemistry: An Indian Journal 2013, 8 (2), 59-66.

[0189] 45. Zhao, Y; Wang, L.; Zhou, Y; Liang, Z.; Tavajohi, N.; Li, B.; Li, T., Solid Polymer Electrolytes with High Conductivity and Transference Number of Li Ions for Li-Based Rechargeable Batteries. Adv Sci (Weinh) 2021, 8 (7), 2003675. 46. Wang, Y; Wu, Z ; Zhang, R.; Chen, Z.; Wei, Z.; Hou, Y; Li, P.; Yang, S.; Huang, Z.;

[0190] Li, N.; Zhi, C., Spider silk inspired polymer electrolyte with well bonded interface and fast kinetics for solid-state lithium-ion batteries. Materials Today 2024.

[0191] 47. Liu, M.; Jin, B.; Zhang, Q.; Zhan, X.; Chen, F., High-performance solid polymer electrolytes for lithium ion batteries based on sulfobetaine zwitterion and poly (ethylene oxide) modified poly siloxane. Journal of Alloys and Compounds 2018, 742, 619-628.

[0192] 48. Liu, X.; Mao, W.; Gong, J.; Liu, H; Shao, Y; Sun, L.; Wang, H; Wang, C., Enhanced Electrochemical Performance of PEO-Based Composite Polymer Electrolyte with Single-Ion Conducting Polymer Grafted SiO(2) Nanoparticles. Polymers (Basel) 2023, 75 (2). 49. Liu, M.; Guan, X.; Liu, H.; Ma, X.; Wu, Q.; Ge, S.; Zhang, H.; Xu, J., Composite solid electrolytes containing single-ion lithium polymer grafted garnet for dendrite-free, long-life allsolid-state lithium metal batteries. Chemical Engineering Journal 2022, 445.

[0193] 50. Tao C., Gao M.-H., Yin B.-H., Li B„ Huang Y.-P., Xu G., Bao J.-J. A promising TPU / PEO blend polymer electrolyte for all-solid-state lithium ion batteries Electrochim. Acta, 257 (2017), pp. 31-39, 10.1016 / j.electacta.2017.10.037

Claims

What is claimed is:

1. A solid polymer electrolyte (SPE) comprising a spidroin and an ion conducting polymer wherein the ion conducting polymer is capable of conducting ions.

2. The SPE of claim 1, wherein the spidroin comprises repeating REP domain wherein amino acid sequence of the repeating REP domain of the spidroin is at least about 70%, about 75%, about 80%, about 85%, about 90%, about 95 % or about 100% identical or similar to SEQ ID NO. 1 or 2.

3. The SPE of claim 1, wherein ratio of the spidroin to the ion conducting polymer by weight is between about 10 / 90 to about 35 / 65.

4. The SPE of claiml wherein the ion comprises lithium ion.

5. The SPE of claim 1, wherein the spidroin is capable of complexing with the ion conducting polymer via interaction between functional groups of the spidrion and the functional groups of ion conducting polymer resulting in reduction of crystallinity in the SPE.

6. The SPE of claim 1, wherein the spidroin comprises an N-H group and the ion conduction polymer comprises a C-O-C group and wherein the N-H group of the spidroin complexes with the C-O-C group of the ion conducting polymer.

7. The SPE of claim 1, wherein the spidroin comprises crystalline and amorphous regions, wherein the ratio of crystalline to amorphous region by weight or number of regions is about 1:10 to about 5:10.

8. The SPE of claim 1, wherein the spidroin comprises beta sheet and alpha helix structures, wherein the ratio of beta sheet to alpha helix structures by weight or number of structures is 1:2 to about 2:1.

9. The SPE of claim 1, wherein the spidroin comprises beta-sheet, beta-spiral, 3 io helix putative structures or a combination thereof, wherein the ratio of the number of beta-sheet putative structures to the number of other putative structures is about 1:2 to about 1:6.

10. The SPE of claim 1, wherein the spidroin comprises amino acid motifs (GAn) / An, (GPGXX)Uand (GGX)Uwherein the length ratio of (GAn) / An: (GPGXX)U: (GGX)nis about 7:15:12 to about 10:15:12.

11. The SPE of claim 1 further comprising lithium salt.

12. The SPE of claim 11 , wherein the lithium salt comprises lithium bis(trifluoromethane sulfonimidc) (LiTFSI), lithium perchlorate (LiC104), lithium hcxafluorophosphatc (LiPF6), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenate (LiAsF6), lithium trifluoromethanesulfonate (LiTf), lithium bis(trifluoromethanesulfonimide) (LiBETI),1 ,2,3-dithiazolidine-4,4,5,5-tetrafluoro- 1 , 1 ,3,3-tetraoxide (LiCTFSI), lithium-bis(oxalate) borate (LiBOB) or a combination thereof.

13. The SPE of claim 1, wherein the ion conducting polymer comprises polyethylene oxide (PEO), polyelthyleneglycol (PEG), polyvinyl alcohol (PVA), polyacrylonitrile (PAN), PS, polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVDF), polyvinyl pyrrolidone (PVP) or a combination thereof.

14. The SPE of claim 13, wherein the PEO is crosslinked with polyethylene glycol) diacrylate (PEGDA) or trimethylolpropane triacrylate (TMPTA).

15. The SPE of claim 1, wherein the spidroin is derived from portions of MaSpl spidroin, MaSp2 spidroin or a combination thereof.

16. A method of preparation of the SPE of claim 1, comprising the steps of a. mixing fibrous protein or spidroin with the ion conducting polymer and lithium salt; b. stirring the mixture for over 8 to over 48 hours; c. casting and drying the mixture of step b to form SPE. d. curing the SPE of step c in a vacuum oven at more than about 20°C to about 50°C.

17. The method of claim 16, further comprising the step of storing the SPE in an argon filled box.

18. The method of preparation of claim 17, wherein in step a the components are mixed within hexafluoroisopropanol (HFIP).

19. The method of preparation of claim 17, wherein in step c the mixture is casted on Teflon.

20. A solid polymer electrolyte (SPE) comprising a fibrous protein and an ion conducting polymer wherein the ion conducting polymer is capable of conducting ions.

21. The SPE of claim 20, wherein the fibrous protein comprises a repeating REP domain wherein amino acid sequence of the repeating REP domain of the spidroin is at least about 70%, about 75%, about 80%, about 85%, about 90%, about 95 % or about 99% identical or similar to SEQ ID NO. 1 or 2.

22. The SPE of claim 20, wherein ratio of the fibrous protein to the ion conducting polymer by weight is between about 10 / 90 to about 35 / 65.

23. The SPE of claim 20, wherein the fibrous protein is capable of complexing with the ion conducting polymer via interaction between functional groups of the fibrous protein and functional groups of the ion conducting polymer resulting in reduction of crystallinity in the SPE.

24. The SPE of claim 20, wherein the fibrous protein comprises an N-H group and the ion conduction polymer comprises a C-O-C group and wherein the N-H group of the fibrous protein complexes with the C-O-C group of the ion conducting polymer.

25. The SPE of claim 20, wherein the fibrous protein comprises crystalline and amorphous regions, wherein the ratio of crystalline to amorphous region by weight or number of regions is about 1:10 to about 5:10.

26. The SPE of claim 20, wherein the fibrous protein comprises beta sheet and alpha helix structures, wherein the ratio of beta sheet to alpha helix structures by weight or number of structures is 1:2 to about 2:1.

27. The SPE of claim 20, wherein the fibrous protein comprises beta-sheet, beta-spiral, 3 io helix putative structures or a combination thereof, wherein the ratio of the number of beta-sheet putative structures to the number of other putative structures is about 1:2 to about 1:6.

28. The SPE of claim 20, wherein the fibrous protein comprises amino acid motifs (GAn) / A n, (GPGXX)u and (GGX)u wherein the length ratio of (GAn) / Au: (GPGXX)U: (GGX)nis about 7:15:12 to about 10:15:12.