Sargassum-derived solid-state electrolytes

Abstract

The present technology relates generally to a solid-state electrolyte including about 30 wt.% to about 70 wt.% sodium alginate, about 1 wt.% to about 5 wt.% fucoidan, about 1 wt.% to about 5 wt.% algal protein, about 0 wt.% to about 45 wt.% a polymer that is not a polysaccharide, and about 10 wt.% to about 30 wt.% conductive salt. The sodium alginate, fucoidan, and algal protein may be extracted from naturally occurring sargassum.

Description

SARGASSUM-DERIVED SOLID-STATE ELECTROLYTESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. Provisional Appl. No. 63 / 567,156, filed March 19, 2024, which is incorporated herein by reference in its entirety for any and all purposes.GOVERNMENT RIGHTS

[0002] This invention was made with government support under 80NSSC19M0236 and 80NSSC22M0025 awarded by The National Aeronautics and Space Administration; and OIA-1849243 and OIA-1849243 awarded by the National Science Foundation. The government has certain rights in the invention.TECHNICAL FIELD

[0003] The present technology relates generally to solid-state electrolytes that include a material derived from sargassum.SUMMARY

[0004] In an aspect, a solid-state electrolyte is disclosed. The solid-state electrolyte includes about 30 wt.% to about 70 wt.% sodium alginate, about 1 wt.% to about 5 wt.% fucoidan, about 1 wt.% to about 5 wt.% algal protein, about 0 wt.% to about 45 wt.% polymer that is not a polysaccharide; and about 10 wt.% to about 30 wt.% conductive salt.

[0005] The conductive salt may include NaCl, Na2HPO4, LiF, LiOH, LiCl, LiCICh, or a combination of two or more thereof. The conductive salt may include NaCl, Na2HPO4, and LiOH in a weight ratio of 1 : 1 :4. The conductive salt may be LiOH. The conductive salt may be LiClO4. The polymer may include polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene oxide (PEO), or a combination of two or more thereof. The polymer may include PEO in a weight ratio with the sodium alginate of about 50:50. The sodium alginate, the fucoidan, and the algal protein may be extracted from sargassum.

[0006] In another aspect, a solid-state capacitor includes a first conductor, a second conductor, and the solid-state electrolyte described herein disposed between the first conductor and the second conductor.

[0007] In another aspect, a solid-state battery includes a cathode, an anode, and the solid- state electrolyte disclosed herein disposed between the cathode and the anode.

[0008] In another aspect, a method of forming a solid-state electrolyte is disclosed. The method includes extracting polar chemical species from sargassum, the polar chemical species including sodium alginate, fucoidan, and algal protein; forming a solution by dissolving the polar chemical species and a conductive salt in water at a temperature of about 70°C to about 100°C; cooling the solution to form a gel; and compressing the gel at a pressure of about 1000 psi to about 8000 psi to form the solid-state electrolyte.

[0009] The method of extracting the polar chemical species from the sargassum may include soaking the sargassum in a calcium chloride solution; contacting the sargassum with a non-polar solvent to extract and remove non-polar chemical species from the sargassum; mixing the sargassum with an acid solution to extract the polar chemical species from the sargassum; and isolating the polar chemical species.

[0010] Isolating the polar chemical species may include precipitating the polar chemical species from the acid solution using a mixture of alcohol and water; after precipitating, filtering the polar chemical species; and after filtering, drying the polar chemical species. The polar chemical species from sargassum may include a weight ratio of sodium alginate to a combination of fucoidan and algal protein of about 85: 15 to about 95:5.

[0011] Forming the solution may further include dissolving a polymer that is not a polysaccharide with the polar chemical species and the conductive salt. The polymer may include polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene oxide (PEO), or a combination of two or more thereof. The conductive salt may include NaCl, Na2HPO4, LiF, LiOH, LiCl, LiCICh, or a combination of two or more thereof.

[0012] Further aspects and embodiments of the present technology are described herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 is an illustration of an anode half-cell used to test electrochemical operation of solid-state electrolytes.

[0014] FIG. 2 is a graph of energy dispersive X-ray spectroscopy (EDS) comparing sargassum-derived composite (“NS A 1” and “NS A 2”) with commercial sodium alginate (“CSA”).

[0015] FIG. 3 is a graph of Fourier-transform infrared spectroscopy (FTIR) comparing sargassum-derived composite (“NS A 1” and “NS A 2”) with commercial sodium alginate (“CSA”).

[0016] FIG. 4 is a thermogram comparing sargassum-derived composite (“NS A 1” and “NSA 2”) with commercial sodium alginate (“CSA”).

[0017] FIG. 5A is a photograph of a pellet of sargassum-derived composite including sodium alginate, fucoidan, and algal protein.

[0018] FIG. 5B is a photograph of a pellet of commercial sodium alginate.

[0019] FIG. 6A is a photograph of a pellet of a composite of commercial sodium alginate, polyethylene oxide, and lithium hydroxide.

[0020] FIG. 6B is a photograph of a pellet of a composite of sargassum-derived composite, polyethylene oxide, and lithium hydroxide.

[0021] FIG. 7A is a Nyquist plot of the coin cell in FIG. 1 with a solid-state electrolyte including 37.5% sargassum-derived composite, 37.5% polyethylene oxide, and 25% lithium hydroxide. The inset shows the schematic circuit employed.

[0022] FIG. 7B is a photograph of the LED lamp powered by the coin cell in FIG. 7A, with a voltage of 2.29 V.

[0023] FIG. 8A is a flow diagram of a process of forming a solid-state electrolyte with sargassum-derived composite.

[0024] FIG. 8B is a flow diagram of a process to extract polar chemical species from sargassum.DETAILED DESCRIPTION

[0025] It is to be appreciated that certain aspects, modes, embodiments, variations and features of the present methods are described below in various levels of detail in order to provide a substantial understanding of the present technology.Definitions

[0026] Unless defined otherwise, all technical and scientific terms used herein generally have the same meaning as commonly understood by one of ordinary skill in the art to which this technology belongs.

[0027] As used herein and in the appended claims, singular articles such as “a” and “an” and “the” and similar referents in the context of describing the elements (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the embodiments and does not pose a limitation on the scope of the claims unless otherwise stated. No language in the specification should be construed as indicating any non-claimed element as essential. For example, reference to “a cell” includes a combination of two or more cells, and the like. Generally, the nomenclature used herein and the laboratory procedures in cell culture, molecular genetics, organic chemistry, analytical chemistry and nucleic acid chemistry and hybridization described below are those well-known and commonly employed in the art.

[0028] As used herein, “about” will be understood by persons of ordinary skill in the art and will vary to some extent depending upon the context in which it is used. If there are uses of the term which are not clear to persons of ordinary skill in the art, given the context in which it is used, “about” will mean up to plus or minus 10% of the particular term - for example, “about 10 wt.%” would be understood to mean “9 wt.% to 11 wt.%.” It is to be understood that when “about” precedes a term, the term is to be construed as disclosing“about” the term as well as the term without modification by “about” — for example, “about 10 wt.%” discloses “9 wt.% to 11 wt.%” as well as disclosing “10 wt.%.”

[0029] The phrase “and / or” as used in the present disclosure will be understood to mean any one of the recited members individually or a combination of any two or more thereof - for example, “A, B, and / or C” would mean “A, B, C, A and B, A and C, B and C, or the combination of A, B, and C.”

[0030] As will be understood by one skilled in the art, for any and all purposes, particularly in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a nonlimiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, etc. As will also be understood by one skilled in the art all language such as “up to,” “at least,” “greater than,” “less than,” and the like include the number recited and refer to ranges which can be subsequently broken down into subranges as discussed above. Finally, as will be understood by one skilled in the art, a range includes each individual member. Thus, for example, a group having 1-3 atoms refers to groups having 1, 2, or 3 atoms. Similarly, a group having 1-5 atoms refers to groups having 1, 2, 3, 4, or 5 atoms, and so forth.

[0031] Throughout this disclosure, various publications, patents, and published patent specifications are referenced by an identifying citation. Also within this disclosure are Arabic numerals referring to referenced citations, the full bibliographic details of which are provided immediately preceding the claims. The disclosures of these publications, patents, and published patent specifications are hereby incorporated by reference into the present disclosure to more fully describe the state of the art to which this invention pertains.The Present Technology

[0032] Disclosed herein are solid-state electrolytes including a composite material derived from sargassum, electrochemical cells including these solid-state electrolytes, and methods of forming these solid-state electrolytes. The electrochemical cells may be primary or secondary batteries, or capacitors. Sargassum is a genus of brown seaweed found in temperate and tropical oceans.

[0033] In one aspect, the solid-state electrolytes including a composite material derived from sargassum is provided. The composite material may include polar chemical species from the sargassum, including sodium alginate, fucoidan, and algal protein. Thus, the solid- state electrolyte may include sodium alginate, fucoidan, algal proteins, and conductive salt, and may further include an additional polymer that is not a polysaccharide.

[0034] The sargassum-derived composite material includes polar chemical species extracted from sargassum. The sargassum-derived composite material primarily includes sodium alginate, but the composite material is extracted from sargassum in such a way as to also include fucoidan and algal proteins in the extracted product. Conventionally, fucoidan and algal proteins are considered impurities that are removed during conventional sodium alginate extraction. Here, fucoidan and algal proteins remain in the extracted composite material, and, surprisingly, provide higher ionic conductivity than sodium alginate alone. The combination of fucoidan and algal proteins may be present in the sargassum-derived composite material at about 2 wt.% to about 20 wt.% (e.g., about 5 wt.% to about 15 wt.%, about 5 wt.% to about 10 wt.%, about 8 wt.% to about 12 wt.%, or about 10%), with the balance being sodium alginate (i.e., about 80 wt.% to about 98 wt.%).

[0035] Fucoidan is a long chain sulfated polysaccharide found in the cell walls of sargassum. The polysaccharide includes L-fucose in its polymer backbone, and the polymer backbone may further include other constituents, including uronic acid, mannuronic acid, galactose, xylose, arabinose, rhamnose, or a combination of two or more thereof. For example, fucoidan may include about 20 wt.% to about 80 wt.% L-fucose, with other constituents making up the balance of the fucoidan. The fucoidan may have a sulfate content of about 5 wt.% to about 70 wt.%. Fucoidan is negatively charged due to the sulfate groups, and is balanced by the presence of metal or non-metal cations.

[0036] The solid-state electrolyte includes about 1 wt.% to about 10 wt.% fucoidan (e.g., about 1 wt.% to 9 wt.%, about 2 wt.% to about 8 wt.%, 3 wt.% to about 7 wt.%, about 4 wt.% to about 6 wt.%, or about 5 wt.%).

[0037] The solid-state electrolyte includes about 1 wt.% to about 10 wt.% algal proteins (e.g., about 1 wt.% to 9 wt.%, about 2 wt.% to about 8 wt.%, 3 wt.% to about 7 wt.%, about4 wt.% to about 6 wt.%, or about 5 wt.%).

[0038] The solid-state electrolyte includes a conductive salt. The conductive salt may include NaCl, Na2HPO4, LiF, LiOH, LiCl, LiCICh, or a combination of two or more thereof. For example, the conductive salt may include NaCl, Na2HPO4, and LiOH in a weight ratio of 1 : 1 :4. As another example, the conductive salt may include LiOH. As another example, the conductive salt may include LiC104. The conductive salt may be present in the solid- state electrolyte at about 10 wt.% to about 30 wt.% (e.g., about 15 wt.% to about 25 wt.%, or about 20 wt.%).

[0039] In addition to the sargassum-derived composite material, the solid-state electrolyte may include an additional polymer that is not a polysaccharide. The additional polymer may include polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene oxide (PEO), or a combination of two or more thereof. The ratio of sargassum-derived composite material to additional polymer may be about 25:75 to about 75:25 (e.g., about 50:50). For example, the additional polymer may be PEO present in a ratio with the sargassum-derived composite of about 50:50. The additional polymer may be present in the solid-state electrolyte at about 0 wt.% to about 45 wt.% (e.g., 18.8 wt.%, 37.5 wt.%, and 56.3%).

[0040] In another aspect, an electrochemical cell is provided that includes the solid-state electrolyte including the composite material derived from sargassum.

[0041] The electrochemical cell may be a capacitor, including a first conductor and a second conductor, with the solid-state electrolyte disposed between the first conductor and the second conductor. The first conductor and second conductor may have the form of plates, foils, or meshes. The first conductor and second conductor may be made of conductive metal (e.g., gold, platinum, silver, copper, aluminum, nickel, zinc, iron, or alloys of two or more thereof).

[0042] The electrochemical cell may be a solid-state battery. The battery may include a cathode, an anode, with the solid-state electrolyte disposed between the cathode and the anode. The cathode may include a cathode active material The anode may include metallic lithium, metallic sodium, metallic magnesium, silicon, or a combination thereof.

[0043] In another aspect, a method of forming a solid-state electrolyte is provided. FIG. 8 A is a flow diagram of the process of forming a solid-state electrolyte. In step 811, polar chemical species are extracted from sargassum to provide a sargassum-derived composite including polar chemical species. The polar chemical species include sodium alginate,fucoidan, and algal protein. In step 812, the sargassum-derived composite is dissolved in water with a conductive salt to form a solution. The polar chemical species may be dissolved in water at a temperature of about 20°C to about 100°C (e.g., about 30°C to about 100°C, about 40°C to about 100°C, about 50°C to about 100°C, about 60°C to about 100°C, about 70°C to about 100°C, about 80°C to about 100°C, about 90°C to about 100°C, or about 100°C). The solution may be formed by heating the water at a temperature of about 70°C to about 100°C (e.g., about 90°C to about 100°C) and stirring the solution to dissolve the polar chemical species. In step 813, the solution is allowed to form a gel by cooling the solution back to a temperature of about 15°C to about 35°C (e.g., about 20°C to about 25°C). In step 814, the gel may be compressed by applying pressure to increase the density of the gel. Compression may be conducted by applying a pressure of about 1000 psi to about 8000 psi to the gel (e.g., about 2000 psi to about 7000 psi, about 3000 psi to about 6000 psi, or about 5000 psi). The gel may be compressed at this pressure for about 1 minute to about 1 hour (e.g., about 1 minute to about 15 minutes, about 2 minutes to about 10 minutes, about 3 minutes to about 8 minutes, or about 5 minutes). The conductive salt may include NaCl, Na2HPO4, LiF, LiOH, LiCl, LiCICh, or a combination of two or more thereof, as described herein.

[0044] The method of forming the solid-state electrolyte may further include dissolving an additional polymer that is not a polysaccharide into the solution at step 812. The additional polymer may include polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene oxide (PEO), or a combination of two or more thereof. The ratio of sargassum-derived composite material to additional polymer may be about 25:75 to about 75:25 (e.g., about 50:50). For example, the additional polymer may be PEO present in a ratio with the sargassum-derived composite of about 50:50.

[0045] FIG. 8B is a flow diagram of a process to extract polar chemical species from sargassum. Prior to extraction, sargassum may be processed by washing the sargassum with water to remove impurities one to five times, then drying and milling the sargassum to produce a sargassum powder. A washing step may be included between each step in the flow diagram in FIG. 8B. Unless otherwise specified, steps are performed at a temperature of about 15°C to about 35°C (e.g., about 20°C).

[0046] In step 801, the sargassum powder may be soaked in CaCh solution (about 0.5% to about 2% w / w or about 1% w / w) with a liquid / solid ratio of about 5 kg to about 20 kgsolvent per kg of dried material (e.g., about 15 kg solvent per kg of dried material) for about 5 hours to about 30 hours (e.g., about 9 hours to about 27 hours, or about 18 hours) with agitation (e.g., stirring). After soaking in CaCh solution, the solid may be washed with water, discarding supernatants.

[0047] In step 802, the sargassum powder may be soaked in non-polar solvent (e.g., di chloromethane) at a liquid / solid ratio of about 5 kg to about 20 kg solvent per kg of dried material (e.g., about 15 kg solvent per kg of dried material) for about 30 minutes to about 24 hours (e.g., about 30 minutes to about 2 hours, about 30 minutes to about 5 hours, or about 1 hour). The solid may then be washed with water, discarding supernatants. Soaking in non-polar solvent may be used to extract and remove non-polar chemical species from the sargassum.

[0048] In step 803, the solid may be soaked in acid solution. The acid solution may be hydrochloric acid in an amount of about 1 % w / w / to about 10% w / w (e.g., about 5% w / w) at a liquid / solid ratio of about 5 kg to about 20 kg solvent per kg of dried material (e.g., about 15 kg solvent per kg of dried material) for about 30 minutes to about 24 hours (e.g., about 30 minutes to about 2 hours, about 30 minutes to about 5 hours, or about 1 hour). The solid may then be washed with water, discarding supernatants. Soaking in acid solution may be used to extract and remove polar chemical species from the sargassum.

[0049] In step 804, the solid may be soaked in alkaline solution. The alkaline solution may include Na2COs in an amount of about 1% w / w to about 5% w / w (e.g., about 3% w / w) at a liquid / solid ratio of about 5 kg to about 20 kg solvent per kg of dried material (e.g., about 15 kg solvent per kg of dried material) for about 30 minutes to about 24 hours (e.g., about 30 minutes to about 2 hours, about 30 minutes to about 5 hours, or about 1 hour). After soaking, water may be added to dilute the liquid / solid ratio by about 1 kg solvent per kg of dried material to about 5 kg solvent per kg of dried material, and the diluted slurry may be rested for about 4 hours to about 24 hours (e.g., 5 hours to 10 hours, or about 8 hours).

[0050] In steps 805 and 806, the polar chemical species are isolated from the rest of the sargassum materials. In step 805, the viscous blend may be separated from the solid material in the slurry. The viscous blend may be separated by centrifugation and / orfiltration. For example, the separation may be via centrifugation at 6000 *g to 10,000 *g for about 1 minute to about 10 minutes (e.g., 8500 *g for 5 minutes).

[0051] In step 806, alginate along with other polar species fucoidan and algal peptides are precipitated from the viscous blend to form the sargassum-derived composite. The precipitation may be via mixing with an alcohol-water solution at 30% to 70% v / v (e.g., 50% v / v) alcohol to water ratio, and with a 2: 1 to 1 :2 v / v (e.g., 1 : 1 v / v) liquid-liquid viscous blend to alcohol-water solution ratio. The alcohol may be ethanol. Following precipitation, the precipitated polar species may be filtered and washed with alcohol before drying to a solid.EXAMPLES

[0052] The present technology is further illustrated by the following Examples, which should not be construed as limiting in any way. The examples herein are provided to illustrate advantages of the present technology and to further assist a person of ordinary skill in the art with preparing or using the compositions and systems of the present technology. The examples should in no way be construed as limiting the scope of the present technology, as defined by the appended claims. The examples can include or incorporate any of the variations, aspects, or embodiments of the present technology described above. The variations, aspects, or embodiments described above may also further each include or incorporate the variations of any or all other variations, aspects or embodiments of the present technology. The following Examples demonstrate the preparation, characterization, and use of illustrative sargassum-derived solid-state electrolytes.

[0053] In this study a solid-state electrolyte for electrochemical cells was prepared using sargassum as raw material. The solid-state electrolyte included sargassum-derived polar composite including sodium alginate, fucoidan, and algal proteins, where the composite has superior electrochemical performance to that of commercially available purified alginate. Recently, excessive amounts of sargassum have been contaminating the tropical coastal areas around the globe. Solid-state electrolytes including composites derived from sargassum may create a market for sargassum, which can be collected or farmed as a raw material for electrochemical solid-state electrolytes.

[0054] Materials and Methods

[0055] Materials. The reagents used for extraction and solid-state electrolyte preparation are described. Acetone (histological grade, > 95%), methanol (anhydrous, 99.8%), hydrochloric acid (HC1, ACS reagent 37%), sodium carbonate (Na2COs, powder > 99.5%, ACS reagent), sodium phosphate dibasic dihydrate (Na2HPO4*2H2O, for molecular biology, > 99.0%), sodium chloride (NaCl, reagent plus 99%), polyethylene oxide (PEO, average Mv600000, powder), polyvinylpyrrolidone (PVP average MW 40000), polyvinyl alcohol (PVA, MW approx. 145000 for synthesis), and purified sodium alginate were used as received. The mesoporous carbon (nanopowder, graphitized, less than 250 ppm Al, Ti, Fe, Ni, Cu, and Zn combined) was dried under vacuum at 120 °C for 12 hours before being used, and l-methyl-2-pyrrolidone (NMP anhydrous, 99.5%) was used directly. In addition, lithium chloride monohydrate (LiCbEbO, 99.996% metal basis), lithium perchlorate (LiCICh, anhydrous, 99.99% metal basis), lithium hydroxide (LiOH, anhydrous 99.995% metal basis), and lithium fluoride (LiF, 99.98% metal basis) were used directly. Poly (vinylidene fluoride) (PVDF, powder Mp 155-160°) was dried under vacuum at 120 °C for 12 hours before using.

[0056] Extraction. Sargassum collected from the north coast of Puerto Rico was washed with tap water and then distilled water to remove impurities. After drying and grinding the sargassum, sodium alginate extraction was performed with an accelerated solvent extractor.

[0057] Specifically, the sargassum powder was soaked in 1% w / w CaCh solution with a liquid / solid ratio of about 15 kg solvent per kg of dried material for about 18 hours with stirring. After soaking in CaCh solution, the solid was washed twice with double-distilled water, discarding supernatants. The sargassum powder was soaked in dichloromethane at a liquid / solid ratio of about 15 kg solvent per kg of dried material for 1 hour. The solid was then washed with double-distilled water, discarding supernatants. The solid was then soaked in 5% w / w hydrochloric acid at a liquid / solid ratio of about 15 kg solvent per kg of dried material for about 1 hour. The solid was then washed with double-distilled water, discarding supernatants. The solid was then soaked in 3% w / w Na2COs at a liquid / solid ratio of about 15 kg solvent per kg of dried material for about 1 hour. After soaking, water was added to dilute the liquid / solid ratio by about 2.5 kg solvent per kg of dried material to a ratio of about 12.5 kg solvent per kg of dried material, and the diluted slurry was rested for about 8 hours. The polar chemical species were isolated as a viscous blend by separating from the solid material in the slurry. The viscous blend was separated bycentrifugation at 8500 *g for 5 minutes. The alginate, along with other polar species fucoidan and algal proteins, were precipitated from the viscous blend via an alcohol-water solution at 50% v / v ethanol to water ratio, and with 1 : 1 v / v liquid-liquid viscous blend to ethanol -water solution ratio. Following precipitation, the precipitated polar species were filtered and washed with ethanol before drying to a solid at about 50°C, forming the sargassum-derived composite. The extraction yield was expressed as kg of alginates per 100 kg of dried seaweed.

[0058] Solid-State Electrolyte Preparation. The commercial sodium alginate (CSA) or sargassum-derived composite (NS A) was mixed with polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), and polyethylene oxide (PEO). The weight ratios of CSA or NSA to PVA were SA 100%, SA:PVA=75:25, SA:PVA=50:50, SA:PVP=75:25, SA:PVP=50:50, SA:PEO=75:25 and SA:PEO=50:50. NaCl, Na2HPO4, LiOH were used as conductive salts. The electrolyte compositions were bulk:salt = 75:25, where “bulk” is the SA or mixture of SA and polymer. The mixtures (1 g) were solubilized in 50 mL of deionized water. The solutions were stirred and heated at 100°C. Pellets were made with the gel using a hydraulic press at 5000 psi for 5 min.

[0059] Half-Cell Preparation. A half-cell graphite anode was prepared by mixing graphite (active material), carbon black (conductive agent), and polyvinylidene fluoride (PVDF) (binder) in a mass ratio of 80: 10: 10 and adding N-methyl-2-pyrrolidone (NMP) as solvent to create a slurry. Then, the slurry was cast on copper foil using a doctor's blade and dried at 90 °C for 24 hours. CR2032-type coin cells were assembled as shown in FIG. 1, with the graphite anode, the experimental solid-state electrolytes, and metallic Li as the counter electrode. All assembly work was carried out inside an Ar-filled glove box, with H2O and O2 concentration < 0.1 ppm.

[0060] Physico-Chemical Characterizations. The sargassum-derived composite materials were characterized by energy dispersive X-ray spectroscopy (EDS), Fourier transformed infrared spectroscopy (FTIR), differential scanning calorimetry (heating ramp of 10 °C min'1under a nitrogen atmosphere and aluminum holder). Electrochemical impedance spectroscopy (EIS) measurements were performed at room temperature in the frequency range of 1 MHz to 0.1 Hz with an amplitude of 10 mV and 10 points measured per decade.

[0061] Results and Discussion

[0062] Polysaccharide Characterization. FIG. 2 is a graph of energy dispersive X-ray spectroscopy (EDS) comparing sargassum-derived composite materials (“NSA 1” and “NSA 2”) with commercial sodium alginate (“CSA”). The EDS analyses assessed the elemental sample composition and detected impurities present in the sargassum-derived composite material (NSA) in comparison to the commercial sodium alginate (CSA). FIG. 2 indicated the NSA and CSA had similar elemental compositions in terms of C, O, Na, S, Ca, but NSA 1 and NSA 2 additionally included Mg and did not include the second S peak at a higher energy.

[0063] FIG. 3 is a graph of Fourier-transform infrared spectroscopy (FTIR) comparing sargassum-derived sodium alginate materials (“NSA 1” and “NSA 2”) with commercial sodium alginate (“CSA”). The FTIR in FIG. 3 was used to analyze the chemical bonds and functional groups present in the samples. Functional groups in sodium alginates, such as carboxyl, hydroxyl, and ester, were identified in the FTIR spectrum. There were no significant differences in the presence or intensity of the peaks for the NSA and CSA samples. The presence of characteristic peaks of glycosidic bonds in the region of 800- 1200 cm’1may indicate the presence of a linear polymer structure. The 1024 cm’1band may be the C-O-C stretching vibration typical of the aliphatic chain, the 1406 cm’1and 1591 cm’1modes may correspond to the symmetric and asymmetric stretching vibration of the carboxylic group, respectively. The peaks at 1081 cm’1and 1024 cm’1were assigned to the C-C and C-0 stretching vibration from the pyranose ring stretching vibration, respectively. The weak signal at 2930 cm’1was assigned to the stretching vibrations of -CEE, and the thick band at 3234 cm’1was assigned to the stretching vibrations of the O-H bond. Peaks below 1000 cm’1were assigned to vibrations corresponding to uronic and mannuronic acid.

[0064] FIG. 4 is a thermogram comparing sargassum-derived sodium alginate materials (“NSA 1” and “NSA 2”) with commercial sodium alginate (“CSA”). DSC was used to study the thermal transition of materials, which provides thermal stability information. Comparing the DSC of NSA to CSA can identify modifications in structure when there are phases at different temperatures. FIG. 4 shows an endothermic peak that starts around 30 °C and finishes near to 100 °C, corresponding to salt dehydration. The exothermic peaks at 245 °C, 260 °C, and 253 °C were seen in CSA, NSA1, and NSA2, respectively. These peaks corresponded to the thermal decomposition temperature of the sodium alginate and are in the range of 240 °C and 300 °C. The differences in the thermal decompositiontemperature of the samples indicated that the NSA1 and NSA2 materials included impurities from sargassum extraction, including fucoidan and algal proteins, which shifted thermal decomposition temperature.

[0065] Solid-State Electrolyte Development. FIG. 5A is a photograph of a pellet of sargassum-derived composite material. FIG. 5B is a photograph of a pellet of commercial sodium alginate. In comparison to the commercial sodium alginate, which appeared as a light beige color, the sargassum-derived composite appeared as a dark brown color, indicating the presence of impurities from sargassum extraction, including fucoidan and algal proteins.

[0066] The conductivity of the pellets was computed with equation (I):where Rb is the system resistance, L is the pellet thickness, and A is the pellet area.

[0067] The conductivity of sodium alginate mixtures with different polymers was investigated. Table 1 provides the conductivity measurements of sargassum-derived composite (“NSA”), commercial sodium alginate (“CSA”), and mixtures of CSA with different polymers including PVA, PVP, and PEO. CSA:PEO at a ratio of 50:50 had a higher conductivity as compared to the other mixtures, and therefore mixtures with 50 wt.% PEO were chosen for further study.Table 1Material (wt.%) Resistance, Rb Thickness, L (cm) Conductivity, o ( iiS / cm ) ( ) 100% NSA 1.63x l040.117 5.4x 10°100% CSA 9.94x l030.076 5.83x 10°25%CSA- 4.56x l040.136 2.26x 10°75%PVA 50%CSA- 1.93x l040.208 8.12x 10°50%PVA 25%CSA- 9.07x l030.174 1.45X 10175%PVP 50%CSA- 1.16x l040.362 2.35X 10150%PVP 50%CSA- 2.21 x lO40.225 7.67x 10°75%PEO 50%CSA- 4.50x l030.288 4.82X 10150%PEO

[0068] The conductivity of alginate mixtures with different salts was also investigated.Table 2 provides conductivity measurements of 50:50 w / w mixtures of commercial sodium alginate or sargassum-derived composite (CSA or NSA) and PEO with different salts. The sodium alginate:PEO:salt or composite:PEO:salt weight ratio was 37.5:37.5:25. The salts used were Na2HPO4, LiF, a mixture containing NaCl:Na2HPO4:LiOH in 1 : 1 :4 proportion, LiOH, LiCl, and LiCICh. The mixtures were dried and pelleted before their conductivity was measured.Table 2Material Resistance, Rb Thickness, L (cm) Conductivity, o(Q) (iiS / cm)CSA-PEO-Na2HPO42.88 1060.101 2.58* 10'2CSA-PEO-LiF l.Ol x lO72.22 1.65X 10’1CSA-PEO-Mixed 4.51 X 1060.290 6.96x l0’2Salts NSA-PEO-Mixed 3.05x l061.26 7.10x 10°Salts CSA:PEO:LiOH 4.04x l020.156 2.90x l02CSA:PEO:LiCl 6.38x l030.117 1.38X 101CSA:PEO:LiClO4 1.51 X 1040.168 8.41 x 10

[0069] As shown in Table 2, the mixture with LiOH salt had a higher conductivity as compared to the other salts tested.

[0070] FIG. 6A is a photograph of a pellet of commercial sodium alginate, polyethylene oxide, and lithium hydroxide. FIG. 6B is a photograph of a pellet of sargassum-derived composite, polyethylene oxide, and lithium hydroxide. The pellet with commercial sodium alginate appeared white in color, and the pellet with sargassum-derived sodium alginate appeared brown in color. The brown color may indicate the presence of impurities from the sargassum extraction, including fucoidan and algal proteins.

[0071] Half-Cell Testing. Electrochemical half-cells in the form of coin cells assembled according to FIG. 1 were tested using the solid-state electrolytes disclosed herein. The coin cells using solid-state electrolytes with commercial sodium alginate had an internal resistance too high for stable operation and suffered electrochemical collapse immediately after the coin cells were sealed. Thereby, it was not possible to measure any voltage in these cells. In comparison, the coin cells using solid-state electrolytes with sargassum- derived composite had measurable voltages, as shown in Table 3.Table 3Sargassum-Derived Solid State Electrolytes Voltage (V)37.5% NSA-37.5% PEO-25%(NaCl+Na2HPO4+LiF) 0.001837.5% NSA-37.5% PEO-25%(NaCl+Na2HPO4+LiOH) 0.002437.5% NSA-37.5% PEO-25% LiF 0.161237.5% NSA-37.5% PEO-25% LiOH 2.2892

[0072] FIG. 7A is a Nyquist plot of the coin cell with the solid-state electrolyte including 37.5% sargassum-derived composite, 37.5% polyethylene oxide, and 25% lithium hydroxide. The inset shows the schematic circuit employed. FIG. 7B is a photograph of the LED lamp powered by the coin cell in FIG. 7A. An LED lamp was used to test the coin cell with the solid-state electrolyte including 37.5% sargassum-derived composite, 37.5% polyethylene oxide, and 25% lithium hydroxide. The coin cell provided an average voltage of 2.29 V and provided enough power to illuminate the LED lamp.REFERENCES

[0073] Guo, Y.; Wu, S.; He, Y.-B.; Kang, F.; Chen, L.; Li, H.; Yang, Q.-H., Solid-state lithium batteries: Safety and prospects. eScience 2022, 2 (2), 138-163.

[0074] Liu, Y.; Sun, P.; Niu, H.; Huang, X.; Rein, G., Propensity to self-heating ignition of open-circuit pouch lithium-ion battery pile on a hot boundary. Fire Safety Journal 2021, 120, 103081.

[0075] Xie, D.; Zhang, M.; Wu, Y.; Xiang, L.; Tang, Y., A Flexible Dual-Ion Battery Based on Sodium-Ion Quasi-Solid-State Electrolyte with Long Cycling Life. 2020, 30 (5), 1906770.

[0076] Yang, H.; Wu, N., Ionic conductivity and ion transport mechanisms of solid-state lithium-ion battery electrolytes: A review. 2022, 10 (5), 1643-1671.

[0077] Sastre, J.; Futscher, M. H.; Pompizi, L.; Aribia, A.; Priebe, A.; Overbeck, J.;Stiefel, M.; Tiwari, A. N.; Romanyuk, Y. E., Blocking lithium dendrite growth in solid-state batteries with an ultrathin amorphous Li-La-Zr-0 solid electrolyte. Communications Materials 2021, 2 (1), 76.

[0078] Chien, Y.-C.; Liu, H.; Menon, A. S.; Brant, W. R.; Brandell, D.; Lacey, M. J., Rapid determination of solid-state diffusion coefficients in Li-based batteries via intermittent current interruption method. Nature Communications 2023, 14 (1), 2289.

[0079] Tufail, M. K.; Zhai, P.; Jia, M.; Zhao, N.; Guo, X., Design of Solid Electrolytes with Fast Ion Transport: Computation-Driven and Practical Approaches. 2023, 4, 0015.

[0080] Ping, W.; Wang, C.; Wang, R.; Dong, Q.; Lin, Z.; Brozena, A. H.; Dai, J.; Luo, J.; Hu, L., Printable, high-performance solid-state electrolyte films. 2020, 6 (47), eabc8641.

[0081] Chen, R.; Li, Q.; Yu, X.; Chen, L.; Li, H., Approaching Practically Accessible Solid-State Batteries: Stability Issues Related to Solid Electrolytes and Interfaces. Chemical Reviews 2020, 120 (14), 6820-6877.

[0082] Yu, C.; Zhao, F.; Luo, J.; Zhang, L.; Sun, X., Recent development of lithium argyrodite solid-state electrolytes for solid-state batteries: Synthesis, structure, stability and dynamics. Nano Energy 2021, 83, 105858.

[0083] Kundu, S.; Kraytsberg, A.; Ein-Eli, Y., Recent development in the field of ceramics solid-state electrolytes: I — oxide ceramic solid-state electrolytes. Journal of Solid State Electrochemistry 2022, 26 (9), 1809-1838.

[0084] Wang, C.; Fu, K.; Kammampata, S. P.; McOwen, D. W.; Samson, A. J.; Zhang, L.; Hitz, G. T.; Nolan, A. M.; Wachsman, E. D.; Mo, Y.; Thangadurai, V.; Hu, L., Garnet- Type Solid-State Electrolytes: Materials, Interfaces, and Batteries. Chemical Reviews 2020, 120 (10), 4257-4300.

[0085] Dirican, M.; Yan, C.; Zhu, P.; Zhang, X., Composite solid electrolytes for all- solid-state lithium batteries. Materials Science and Engineering: R: Reports 2019, 136, 27- 46.

[0086] Zhang, Z.; Wang, X.; Li, X.; Zhao, J.; Liu, G.; Yu, W.; Dong, X.; Wang, J., Review on composite solid electrolytes for solid-state lithium-ion batteries. Materials Today Sustainability 2023, 21, 100316.

[0087] Dennis, J. O.; Shukur, M. F.; Aldaghri, O. A.; Ibnaouf, K. H.; Adam, A. A.; Usman, F.; Hassan, Y. M.; Alsadig, A.; Danbature, W. L.; Abdulkadir, B. A., A Review of Current Trends on Polyvinyl Alcohol (PVA)-Based Solid Polymer Electrolytes. 2023, 28 (4), 1781.

[0088] Campanella, D.; Bertoni, G.; Zhu, W.; Trudeau, M.; Girard, G.; Savoie, S.; Clement, D.; Guerfi, A.; Vijh, A.; George, C.; Belanger, D.; Paolella, A., Gram-scale carbothermic control of LLZO garnet solid electrolyte particle size. Chemical Engineering Journal 2023, 457, 141349.

[0089] Wang, L.; Li, I; Lu, G.; Li, W.; Tao, Q.; Shi, C.; Jin, H.; Chen, G.; Wang, S., Fundamentals of Electrolytes for Solid-State Batteries: Challenges and Perspectives. Frontiers in Materials 2020, 7.

[0090] Zhao, Q.; Stalin, S.; Zhao, C.-Z.; Archer, L. A., Designing solid-state electrolytes for safe, energy-dense batteries. Nature Reviews Materials 2020, 5 (3), 229-252.

[0091] Anne, D. Sargassun Uses Guide: A resource for Caribbean researchers, entrepreneurs and policy makers; 2020.

[0092] Vazquez-Delfin, E.; Freile-Pelegrin, Y.; Salazar-Garibay, A.; Serviere-Zaragoza, E.; Mendez-Rodriguez, L. C.; Robledo, D., Species composition and chemical characterization of Sargassum influx at six different locations along the Mexican Caribbean coast. Science of The Total Environment 2021, 795, 148852.

[0093] Madadi, R.; Maljaee, EL; Serafim, L. S.; Ventura, S. P. M., Microalgae as Contributors to Produce Biopolymers. 2021, 19 (8), 466.

[0094] Montes, L.; Gisbert, M.; Hinojosa, I.; Sineiro, J.; Moreira, R., Impact of drying on the sodium alginate obtained after polyphenols ultrasound-assisted extraction from Ascophyllum nodosum seaweeds. Carbohydrate Polymers 2021, 272.

[0095] El Kharbachi, A.; Wind, J.; Ruud, A.; Hogset, A. B.; Nygard, M. M.; Zhang, J.; Sorby, M. H.; Kim, S.; Cuevas, F.; Orimo, S. I.; Fichtner, M.; Latroche, M.; Fjellvag, H.; Hauback, B. C., Pseudo-ternary LiBH(4).LiCl.P(2)S(5) system as structurally disordered bulk electrolyte for all-solid-state lithium batteries. Phys Chem Chem Phys 2020, 22 (25), 13872-13879.

[0096] Wang, G.; Liu, H.; Liang, Y.; Wang, C.; Fan, L.-Z., Composite polymer electrolyte with three-dimensional ion transport channels constructed by NaCl template for solid-state lithium metal batteries. Energy Storage Materials 2022, 45, 1212-1219.

[0097] Lim, Y. J.; Han, J.; Kim, H. W.; Choi, Y.; Lee, E.; Kim, Y., An epoxy-reinforced ceramic sheet as a durable solid electrolyte for solid state Na-ion batteries. Journal of Materials Chemistry A 2020, 8 (29), 14528-14537.

[0098] Chen, X.; Dou, S.; Li, W.; Liu, D.; Zhang, Y.; Zhao, Y.; Li, Y.; Zhao, J.; Zhang, X., All solid state electrochromic devices based on the LiF electrolyte. Chemical Communications 2020, 56 (37), 5018-5021.

[0099] Shi, G.; Ohno, H., Electrochemical behaviour of hemin and PEO-hemin in ion- conductive polymer matrices. Journal of Electroanalytical Chemistry and Interfacial Electrochemistry 1991, 314 (1), 59-69.

[0100] Jia, W.; Li, Z.; Wu, Z.; Wang, L.; Wu, B.; Wang, Y.; Cao, Y.; Li, J., Graphene oxide as a filler to improve the performance of PAN-LiC104 flexible solid polymer electrolyte. Solid State Ionics 2018, 315, 7-13.

[0101] Manthiram, A.; Yu, X.; Wang, S., Lithium battery chemistries enabled by solid- state electrolytes. Nature Reviews Materials 2017, 2 (4), 16103.

[0102] Tatis, D.; Sierra, H.; Arzuaga, E. In Residual Neural Network Architectures to Improve Prediction Accuracy of Properties of Materials, 2020 IEEE International Conference on Big Data (Big Data), 10-13 Dec. 2020; 2020; pp 2915-2918.

[0103] Jha, D.; Ward, L.; Yang, Z.; Wolverton, C.; Foster, I.; Liao, W.-k.; Choudhary, A.; Agrawal, A., IRNet. In Proceedings of the 25th ACM SIGKDD International Conference on Knowledge Discovery & Data Mining, 2019; pp 2385-2393.

[0104] Nikonenko, N. A.; Buslov, D. K.; Sushko, N. I.; Zhbankov, R. G., Investigation of stretching vibrations of glycosidic linkages in disaccharides and polysaccharides with use of I.R. spectra deconvolution. 2000, 57 (4), 257-262.

[0105] Bock, P.; Gierlinger, N., Infrared and Raman spectra of lignin substructures: Coniferyl alcohol, abietin, and coniferyl aldehyde. 2019, 50 (6), 778-792.

[0106] Xiao, Q.; Gu, X.; Tan, S., Drying process of sodium alginate films studied by two- dimensional correlation ATR-FTIR spectroscopy. Food Chemistry 2014, 164, 179-184.

[0107] Hong, T.; Yin, J.-Y.; Nie, S.-P.; Xie, M.-Y., Applications of infrared spectroscopy in polysaccharide structural analysis: Progress, challenge and perspective. Food Chemistry: X 2021, 12, 100168.

[0108] Gomez-Ordonez, E.; Ruperez, P., FTIR-ATR spectroscopy as a tool for polysaccharide identification in edible brown and red seaweeds. Food Hydrocolloids 2011, 25 (6), 1514-1520.

[0109] dos Santos Araujo, P.; Belini, G. B.; Mambrini, G. P.; Yamaji, F. M.; Waldman, W. R., Thermal degradation of calcium and sodium alginate: A greener synthesis towards calcium oxide micro / nanoparticles. International Journal of Biological Macromolecules 2019, 140, 749-760.EQUIVALENTS

[0110] While certain embodiments have been illustrated and described, a person with ordinary skill in the art, after reading the foregoing specification, can effect changes, substitutions of equivalents and other types of alterations to the compounds of the present technology or salts, pharmaceutical compositions, derivatives, prodrugs, metabolites, tautomers or racemic mixtures thereof as set forth herein. Each aspect and embodiment described above can also have included or incorporated therewith such variations or aspects as disclosed in regard to any or all of the other aspects and embodiments.[OHl] The present technology is also not to be limited in terms of the particular aspects described herein, which are intended as single illustrations of individual aspects of the present technology. Many modifications and variations of this present technology can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. Functionally equivalent methods within the scope of the present technology, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. It is to be understood that this present technology is not limited to particular methods, reagents, compounds, compositions, labeled compounds or biological systems, which can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to be limiting. Thus, it is intended that the specification be considered as exemplary only withthe breadth, scope and spirit of the present technology indicated only by the appended claims, definitions therein and any equivalents thereof.

[0112] The embodiments, illustratively described herein may suitably be practiced in the absence of any element or elements, limitation or limitations, not specifically disclosed herein. Thus, for example, the terms “comprising,” “including,” “containing,” etc. shall be read expansively and without limitation. Additionally, the terms and expressions employed herein have been used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the claimed technology. Additionally, the phrase “consisting essentially of’ will be understood to include those elements specifically recited and those additional elements that do not materially affect the basic and novel characteristics of the claimed technology. The phrase “consisting of’ excludes any element not specified.

[0113] In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group. Each of the narrower species and subgeneric groupings falling within the generic disclosure also form part of the invention. This includes the generic description of the invention with a proviso or negative limitation removing any subject matter from the genus, regardless of whether or not the excised material is specifically recited herein.

[0114] As will be understood by one skilled in the art, for any and all purposes, particularly in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a nonlimiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, etc. As will also be understood by one skilled in the art all language such as “up to,” “at least,” “greater than,” “less than,” and the like, include the number recited and refer to ranges which can be subsequently broken down into subranges as discussed above. Finally, as will be understood by one skilled in the art, a range includes each individual member.

[0115] All publications, patent applications, issued patents, and other documents (for examplejournals, articles and / or textbooks) referred to in this specification are herein incorporated by reference as if each individual publication, patent application, issued patent, or other document was specifically and individually indicated to be incorporated by reference in its entirety. Definitions that are contained in text incorporated by reference are excluded to the extent that they contradict definitions in this disclosure.

[0116] The present technology may include, but is not limited to, the features and combinations of features recited in the following lettered paragraphs, it being understood that the following paragraphs should not be interpreted as limiting the scope of the claims as appended hereto or mandating that all such features must necessarily be included in such claims:A. A solid-state electrolyte comprising: about 30 wt.% to about 70 wt.% sodium alginate; about 1 wt.% to about 5 wt.% fucoidan; about 1 wt.% to about 5 wt.% algal protein; about 0 wt.% to about 45 wt.% polymer that is not a polysaccharide; and about 10 wt.% to about 30 wt.% conductive salt.B. The solid-state electrolyte of Paragraph A, wherein the conductive salt comprises NaCl,Na2HPO4, LiF, LiOH, LiCl, LiCICh, or a combination of two or more thereof.C. The solid-state electrolyte of Paragraph A or Paragraph B, wherein the conductive salt comprises NaCl, Na2HPO4, and LiOH in a weight ratio of 1 : 1 :4.D. The solid-state electrolyte of any one of Paragraphs A-C, wherein the conductive salt comprises LiOH or consists of LiOH.E. The solid-state electrolyte of Paragraph A or Paragraph B, wherein the conductive salt comprises LiClO4 or consists of LiClO4.F. The solid-state electrolyte of any one of Paragraphs A-E, wherein the polymer comprises polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene oxide (PEO), or a combination of two or more thereof.G. The solid-state electrolyte of any one of Paragraphs A-F, wherein the polymer comprises PEO in a weight ratio with the sodium alginate of about 50:50.H. The solid-state electrolyte of any one of Paragraphs A-G, wherein the sodium alginate, the fucoidan, and the algal protein are extracted from sargassum.I. A solid-state capacitor comprising: a first conductor of any aspect or embodiment of the present disclosure; a second conductor of any aspect or embodiment of the present disclosure; and the solid-state electrolyte of any one of Paragraphs A-H disposed between the first conductor and the second conductor.J. A solid-state battery comprising: a cathode of any aspect or embodiment of the present disclosure; an anode of any aspect or embodiment of the present disclosure; and the solid-state electrolyte of any one of Paragraphs A-H disposed between the cathode and the anode.K. A method of forming a solid-state electrolyte comprising: extracting polar chemical species from sargassum, the polar chemical species comprising sodium alginate, fucoidan, and algal protein; forming a solution by dissolving the polar chemical species and a conductive salt in water at a temperature of about 70°C to about 100°C; cooling the solution to form a gel; and compressing the gel at a pressure of about 1000 psi to about 8000 psi to form the solid-state electrolyte.L. The method of Paragraph K, wherein extracting the polar chemical species from the sargassum comprises: soaking the sargassum in a calcium chloride solution; contacting the sargassum with a non-polar solvent to extract and remove non-polar chemical species from the sargassum; mixing the sargassum with an acid solution to extract the polar chemical species from the sargassum; and isolating the polar chemical species.M. The method of Paragraph L, wherein isolating the polar chemical species comprises: precipitating the polar chemical species from the acid solution using a mixture of alcohol and water; after precipitating, filtering the polar chemical species; and after filtering, drying the polar chemical species.N. The method of any one of Paragraphs K-M, wherein the polar chemical species from sargassum comprise a weight ratio of sodium alginate to a combination of fucoidan and algal protein of about 85: 15 to about 95:5.O. The method of any one of Paragraphs K-M, wherein forming the solution further comprises dissolving a polymer that is not a polysaccharide with the polar chemical species and the conductive salt.P. The method of Paragraph O, wherein the polymer that is not a polysaccharide comprises polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene oxide (PEO), or a combination of two or more thereof.Q. The method of any one of Paragraphs K-P, wherein the conductive salt comprises NaCl,Na2HPO4, LiF, LiOH, LiCl, LiCICh, or a combination of any two or more thereof.

[0117] Other embodiments are set forth in the following claims, along with the full scope of equivalents to which such claims are entitled.

Claims

CLAIMS1. A solid-state electrolyte comprising: about 30 wt.% to about 70 wt.% sodium alginate; about 1 wt.% to about 5 wt.% fucoidan; about 1 wt.% to about 5 wt.% algal protein; about 0 wt.% to about 45 wt.% polymer that is not a polysaccharide; and about 10 wt.% to about 30 wt.% conductive salt.

2. The solid-state electrolyte of claim 1, wherein the conductive salt comprises NaCl,Na2HPO4, LiF, LiOH, LiCl, LiCICh, or a combination of two or more thereof.

3. The solid-state electrolyte of claim 2, wherein the conductive salt comprises NaCl,Na2HPO4, and LiOH in a weight ratio of 1 : 1 :4.

4. The solid-state electrolyte of claim 2, wherein the conductive salt is LiOH.

5. The solid-state electrolyte of claim 2, wherein the conductive salt is LiC104.

6. The solid-state electrolyte of claim 1, wherein the polymer comprises polyvinyl alcohol(PVA), polyvinylpyrrolidone (PVP), polyethylene oxide (PEO), or a combination of two or more thereof.

7. The solid-state electrolyte of claim 6, wherein the polymer comprises PEO in a weight ratio with the sodium alginate of about 50:50.

8. The solid-state electrolyte of claim 1, wherein the sodium alginate, the fucoidan, and the algal protein are extracted from sargassum.

9. A solid-state capacitor comprising: a first conductor; a second conductor; and the solid-state electrolyte of any one of claims 1-8 disposed between the first conductor and the second conductor.

10. A solid-state battery comprising: a cathode; an anode; andthe solid-state electrolyte of any one of claims 1-8 disposed between the cathode and the anode.

11. A method of forming a solid-state electrolyte comprising: extracting polar chemical species from sargassum, the polar chemical species comprising sodium alginate, fucoidan, and algal protein; forming a solution by dissolving the polar chemical species and a conductive salt in water at a temperature of about 70°C to about 100°C; cooling the solution to form a gel; and compressing the gel at a pressure of about 1000 psi to about 8000 psi to form the solid-state electrolyte.

12. The method of claim 11, wherein extracting the polar chemical species from the sargassum comprises: soaking the sargassum in a calcium chloride solution; contacting the sargassum with a non-polar solvent to extract and remove non-polar chemical species from the sargassum; mixing the sargassum with an acid solution to extract the polar chemical species from the sargassum; and isolating the polar chemical species.

13. The method of claim 12, wherein isolating the polar chemical species comprises: precipitating the polar chemical species from the acid solution using a mixture of alcohol and water; after precipitating, filtering the polar chemical species; and after filtering, drying the polar chemical species.

14. The method of claim 12, wherein the polar chemical species from sargassum comprise a weight ratio of sodium alginate to a combination of fucoidan and algal protein of about 85:15 to about 95:5.

15. The method of claim 11, wherein forming the solution further comprises dissolving a polymer that is not a polysaccharide with the polar chemical species and the conductive salt.

16. The method of claim 15, wherein the polymer comprises polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene oxide (PEO), or a combination of two or more thereof.

17. The method of claim 11, wherein the conductive salt comprises NaCl, Na2HPO4, LiF,LiOH, LiCl, LiCICh, or a combination of two or more thereof.

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