Polymer batteries derived from biomass

Abstract

A polymer battery is disclosed. The polymer battery comprises a cathode comprising a cathode active material comprising a polysaccharide functionalised with one or more cathode redox-active organic moiety. The polymer battery also comprises an anode comprising zinc, magnesium or an anode active material comprising a polysaccharide functionalised with one or more anode redox-active organic moiety. The polymer battery further comprises an electrolyte solution.

Description

POLYMER BATTERIES DERIVED FROM BIOMASSPRIORITY DOCUMENT

[0001] The present application claims priority from Australian Provisional Patent Application No. 2024904079 titled “POLYMER BATTERIES DERIVED FROM BIOMASS” and filed on 10 December 2024, the content of which is hereby incorporated by reference in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates to batteries.BACKGROUND

[0003] Polymer batteries, including metal / polymer hybrid (MPH) batteries and all-polymer batteries (ARB), are rechargeable batteries that utilise polymer-based electrodes. In these batteries, one or both of the cathode and anode can be composed of polymers rather than conventional metals like lithium metal. An electrolyte serves as the medium for ion transport between the polymer electrodes, enabling efficient charge and discharge cycles.

[0004] The use of polymer electrodes allows for highly flexible, lightweight, and thin battery designs. This approach supports the development of various battery types, including ARBs, MPH, 3D-printed batteries and custom-shaped batteries.

[0005] Polymer batteries are typically manufactured using petrochemical -derived polymers and, for this reason, they present significant environmental challenges. At the end of their lifecycle, these batteries contribute to microplastic and nanoplastic pollution, as the polymer components degrade into tiny particles that persist in the environment. This pollution is difficult to remediate and poses risks to ecosystems and human health. Additionally, the reliance on petrochemical sources for battery materials perpetuates dependence on non-renewable resources, further exacerbating environmental concerns. These issues highlight the need for alternative battery technologies that minimise plastic pollution and reduce reliance on fossil-based inputs.

[0006] There is a need for polymer batteries that overcome one or more of the disadvantages of known polymer batteries. Alternatively, or in addition, there is a need for polymer batteries that provide a useful alternative to known polymer batteries.SUMMARY

[0007] According to a first aspect, there is provided a polymer battery comprising: a cathode comprising a cathode active material comprising a polysaccharide functionalised with one or more cathode redox-active organic moiety; an anode comprising metallic zinc, magnesium or an anode active material comprising a polysaccharide functionalised with one or more anode redox-active organic moiety; and an electrolyte solution.

[0008] In embodiments of the first aspect, the polysaccharide of the cathode active material and / or the anode active material is selected from the group consisting of cellulose, starch, chitin, chitosan, alginate, and derivatives of any of the aforementioned. For example, the polysaccharide of the cathode active material and / or the anode active material may be cellulose.

[0009] In embodiments of the first aspect, the cathode redox-active organic moiety is selected from the group consisting of organic nitroxide radicals, phenothiazine, 2,5-di-substituted 1,4-dimethoxybenzene, and derivatives of any of the aforementioned.

[0010] In embodiments of the first aspect, the anode redox-active organic moiety is selected from the group consisting of viologen, anthraquinone, azobenzene, phenazine, and derivatives of any of the aforementioned.

[0011] In embodiments of the first aspect, the cathode redox-active organic moiety comprises 2, 2,6,6- tetramethylpiperidinyloxy (TEMPO). For example, the cathode active material may comprise TEMPO- cellulose or TEMPO-alginate.

[0012] In embodiments of the first aspect, the anode redox-active organic moiety comprises an anthraquinone. For example, the anode active material may comprise anthraquinone-cellulose.

[0013] The cathode and anode electrodes may be optimised for electrochemical performance with specific capacities of 172 mAh / g for cathodes and 259 mAh / g for anodes.

[0014] In embodiments of the first aspect, the anode active material comprises a polysaccharide functionalised with one or more anode redox-active organic moiety selected from the group consisting of viologen and anthraquinone and the electrolyte comprises salt water.

[0015] In embodiments of the first aspect, the anode comprises metallic zinc or magnesium and the electrolyte is selected from one or more of the group consisting of aqueous zinc chloride and perchloratesolution.

[0016] According to a second aspect, there is provided a cathode active material comprising a polysaccharide functionalised with one or more cathode redox-active organic moiety.

[0017] In embodiments of the second aspect, the cathode redox-active organic moiety is selected from the group consisting of organic nitroxide radicals, phenothiazine, 2,5-di-substituted 1,4- dimethoxybenzene, and derivatives of any of the aforementioned.

[0018] According to a third aspect, there is provided an anode active material comprising a polysaccharide functionalised with one or more anode redox-active organic moiety.

[0019] In embodiments of the third aspect, the anode redox-active organic moiety is selected from the group consisting of viologen, anthraquinone, azobenzene, phenazine, and derivatives of any of the aforementioned.

[0020] According to a fourth aspect, there is provided a method of fabricating an electrode active material for use in batteries, comprising modifying a polysaccharide with one or more redox-active organic moiety.

[0021] In embodiments of the fourth aspect, the electrode active material is a cathode active material and the redox-active organic moiety is selected from the group consisting of organic nitroxide radicals, phenothiazine, 2,5-di-substituted 1 ,4-dimethoxybenzene, and derivatives of any of the aforementioned.

[0022] In embodiments of the fourth aspect, the electrode active material is an anode active material and the redox-active organic moiety is selected from the group consisting of viologen, anthraquinone, azobenzene, phenazine, and derivatives of any of the aforementioned.

[0023] According to a fifth aspect, there is provided a method for assembling a polymer battery, comprising: providing a cathode electrode comprising a cathode active material mixed with carbon, said cathode active material comprising a polysaccharide functionalised with one or more cathode redoxactive organic moiety; providing an anode electrode comprising metallic zinc, magnesium or an anode active material mixed with carbon, said anode active material comprising a polysaccharide functionalised with one or more anode redox-active organic moiety; combining the cathode electrodes and the anode electrode with a salt water-based electrolyte; and assembling the components into a rechargeable electrochemical cell.

[0024] In embodiments of the fifth aspect, the cathode redox-active organic moiety is selected from the group consisting of organic nitroxide radicals, phenothiazine, 2,5-di-substituted 1,4-dimethoxybenzene, and derivatives of any of the aforementioned.

[0025] In embodiments of the fifth aspect, the anode redox-active organic moiety is selected from the group consisting of viologen, anthraquinone, azobenzene, phenazine, and derivatives of any of the aforementioned.

[0026] In embodiments of the fifth aspect, the carbon is selected from one or more of the group consisting of carbon nanotubes and carbon black.BRIEF DESCRIPTION OF THE FIGURES

[0027] Embodiments of the present disclosure will be discussed with reference to the accompanying figures wherein:

[0028] Figure 1 shows ATR-IR spectroscopic characterization of bromine -functional cellulose Pl, including a comparison with cellulose;

[0029] Figure 2 shows ATR-IR spectroscopic characterization of bromine -functional cellulose Pl, cellulose-g-oligo(TMPA) P2 and cellulose-g-oligo(TEMPO acrylate) P3;

[0030] Figure 3 shows 'HNMR spectroscopic characterization of bromine -functional cellulose Pl and cellulose-g-oligo(TMPA) P2, *DMS0-< , and **H2O;

[0031] Figure 4 shows EPR spectroscopic characterization (solid state) of cellulose-g-oligo(TEMPO acrylate) P3. ACT was used as a standard in radical quantification;

[0032] Figure 5 shows ATR-IR characterization of cellulose-g-anthraquinone P4, including a comparison with cellulose;

[0033] Figure 6 shows1H NMR spectroscopic characterization of cellulose-g-anthraquinone P4, *DMSO-<7<5, and **H2O;

[0034] Figure 7 shows UV-Vis spectroscopic characterization of cellulose-g-anthraquinone P4 and grafted anthraquinone. The materials were quantified with a calibration using anthraquinone -2 -carboxylic acid as a standard (in DMSO);

[0035] Figure 8 shows SEM morphologies of the electrode composite of (a) cellulose-g-oligo(TEMPOacrylate) P3 / MWCNT, (b) cellulose-g-oligo(TEMPO acrylate) P3 / N234, (c) cellulose-g-anthraquinone P4 / MWCNT, and (d) cellulose-g-anthraquinone P4 / N234. The composite ratio is polymer: carbon additives = 50:50;

[0036] Figure 9 shows cyclic voltammetry analysis of a Zn|| cellulose-g-oligo(TEMPO acrylate) P3 battery (anode- Zn, Cathode- P3, cathode composite- P3:MWCNT=50:50, electrolyte- 2M Zn(C104)2);

[0037] Figure 10 shows long cycling performance of Zn|| cellulose-g-oligo(TEMPO acrylate) P3 battery (anode- Zn, Cathode- P3, cathode composite- P3:MWCNT=50:50, electrolyte- 2M Zn(ClC>4)2, active polymer loading- 3.3 mg cm'2);

[0038] Figure 11 shows galvanostatic charge -discharge profile of Zn|| cellulose-g-oligo(TEMPO acrylate) P3 battery (anode- Zn, Cathode- P3, cathode composite- P3:MWCNT=50:50, electrolyte- 2M Zn(ClC>4)2, active polymer loading- 3.3 mg cm'2);

[0039] Figure 12 shows cyclic voltammetry analysis of Zn||P4 battery (anode- Zn, Cathode- P4, cathode composite- P4:MWCNT=50:50, electrolyte- 2M Zn(C104)2);

[0040] Figure 13 shows long cycling performance of Zn||P4 battery (anode- Zn, Cathode- P4, cathode composite- P4:MWCNT=50:50, electrolyte- 2M Zn(ClC>4)2, active polymer loading- 3.3 mg cm'2);

[0041] Figure 14 shows a galvanostatic charge-discharge profile of Zn||P4 battery (anode- Zn, Cathode- P4, cathode composite- P4:MWCNT=50:50, electrolyte- 2M Zn(ClC>4)2, active polymer loading- 3.3 mg cm'2);

[0042] Figure 15 shows cyclic voltammetry analysis of P4||P3 battery at different scan rates (anode- P4, Cathode- P3, anode composite - P4:MWCNT=50:50, cathode composite- P3:MWCNT=50:50, electrolyte- IM NaCl);

[0043] Figure 16 shows a galvanostatic charge discharge rate performance at different current densities of P4||P3 battery (anode- P4, cathode- P3, anode composite - P4:N234=50:50, cathode composite- P3:N234=50:50, limited active material is P3 (loading = 2.3 mg cm'2), electrolyte- 3M NaCl);

[0044] Figure 17 shows a galvanostatic charge discharge profile at different current densities of P4||P3 battery (anode- P4, cathode- P3, anode composite - P4:N234=50:50, cathode composite- P3:N234=50:50, limited active material is P3 (loading = 2.3 mg cm'2), electrolyte- 3M NaCl);

[0045] Figure 18 shows long cycling performance of P4||P3 batery (anode- P4, cathode- P3, anode composite - P4:N234=50:50, cathode composite- P3:N234=50:50, limited active material is P3 (loading = 6 mg cm'2), electrolyte- 3M NaCl);

[0046] Figure 19 shows a galvanostatic charge discharge profde for different cycles of the long cycling P4||P3 batery (anode- P4, cathode- P3, anode composite - P4:N234=50:50, cathode composite- P3:N234=50:50, limited active material is P3 (loading = 6 mg cm'2), electrolyte- 3M NaCl);

[0047] Figure 20 shows a Ragone plot to compare Swagelok cells (For batery 1 and 2, anode- P4, cathode-P3, anode composite - P4:N234=50:50, cathode composite- P3:N234=50:50, limited active material is P3 (loading = 2.3 mg cm'2(for batery 1), 3.1 mg cm'2(for batery 2)), electrolyte: 3M NaCl);

[0048] Figure 21 shows long cycling performance of P4||P3 pouch batery (anode- P4, cathode- P3, anode composite - P4:N234=50:50, cathode composite- P3:N234=50:50, limited active material is P3 (loading = 15 mg cm'2), electrolyte- 3M NaCl);

[0049] Figure 22 shows a galvanostatic charge discharge profde for different cycles of the long cycling P4||P3 pouch batery (anode- P4, cathode- P3, anode composite - P4:N234=50:50, cathode composite- P3:N234=50:50, limited active material is P3 (loading = 15 mg cm'2), electrolyte- 3M NaCl); and

[0050] Figure 23 shows a digital photo of two P4||P3 pouch cells in series to illuminate an LED.DESCRIPTION OF EMBODIMENTS

[0051] The present disclosure arises from the inventors’ discovery that chemical modification of polysaccharides, including cellulose, starch, chitosan, and alginate, with redox-active organic functionalities, including nitroxide radicals, phenothiazine, anthraquinone, and viologen can be used to produce biomass-based electrode materials. These materials can be used to fabricate biomass-based allpolymer bateries or they can be incorporated with zinc or magnesium to produce hybrid bateries.

[0052] According to the present disclosure, the synthesis of biomass-derived (i.e., polysaccharide) electrode materials is achieved through chemical modification of hydroxyl (-OH), carboxylic acid (- COOH) and amino (-NFL) functionalities with one or more redox-active groups. Depending on the specific structure of the polysaccharide, the linkages between the polysaccharide backbone and the redoxactive group could be an ester, amide or quatemized amine.

[0053] Provided herein is a polymer batery. The polymer batery comprises a cathode comprising a cathode active material comprising a polysaccharide functionalised with one or more cathode redox-active organic moiety. The polymer battery also comprises an anode comprising zinc, magnesium or an anode active material comprising a polysaccharide functionalised with one or more anode redox-active organic moiety. The polymer battery further comprises an electrolyte solution.

[0054] When the anode comprises zinc or magnesium the polymer battery is referred to herein as a hybrid battery whereas when the anode comprises an anode active material comprising a polysaccharide functionalised with one or more anode redox-active organic moiety the polymer battery is referred to herein as an all-polymer battery.

[0055] The cathode active material and the anode active material are fabricated by modifying a polysaccharide with one or more redox-active organic moiety. As used herein, the term “organic” means a molecule containing at least one carbon (C) atom.

[0056] Polysaccharides are high molecular weight carbohydrates composed of long chains of monosaccharide units linked by glycosidic bonds. These macromolecules are abundant in nature. Common examples of polysaccharides include cellulose, starch, chitosan, and alginate. Polysaccharides can be derived from biomass sources such as wood, agricultural residues, algae, and crustacean shells through established extraction and purification processes. The renewable nature of biomass enables the sustainable production of polysaccharides.

[0057] The polysaccharides used herein for the cathode active material and / or the anode active material may be selected from the group consisting of cellulose, starch, chitin, chitosan, alginate, and derivatives of any of the aforementioned.

[0058] As used herein, the term “derivatives” when used in relation to a molecule, compound or moiety means a chemically modified compound wherein the modification is considered routine by the ordinary skilled chemist, such as an ester or an amide of an acid, an alkoxy of an alcohol, an ester of an alcohol, an amide of an amino, an alkylamino of an amine, a halogen for a hydrogen, etc (see, Ahluwalia V.K., Dhingra S., Advanced Experimental Organic Chemistry, CRC Press 2025).

[0059] The cathode redox-active organic moiety may be an organic nitroxide radical, phenothiazine, 2,5-di-substituted 1,4-dimethoxybenzene, or a derivative of any of the aforementioned. For example, the organic nitroxide radical may be 2,2,6,6-tetramethylpiperidinyloxy (TEMPO).

[0060] For example, the polysaccharide of the cathode active material and / or the anode active material may be cellulose. In another example, the polysaccharide of the cathode active material and / or the anode active material may be starch. The hydroxyl groups on starch or cellulose can be reacted with bromo isopropylbromide to form bromo -functional polysaccharides; the latter is used as an initiator to controlthe polymerization of 2,2,6,6-tetramethylpiperidine acrylate (acrylamide) to form oligomer grafting prepolymers. Following oxidation, a TEMPO functional starch or cellulose can be produced.

[0061] In another example, the polysaccharide of the cathode active material and / or the anode active material may be alginate. The carboxylic acids on alginate will react with NH2-TEMPO to form amide bonds.

[0062] Thus, provided herein is a cathode active material comprising a polysaccharide functionalised with one or more cathode redox-active organic moiety.

[0063] The anode redox-active organic moiety may be viologen, anthraquinone, azobenzene, phenazine, or a derivative of any of the aforementioned. For example, the anode redox-active organic moiety may be anthraquinone. The hydroxyl groups on starch or cellulose will react with anthraquinone carboxylic chloride to form anthraquinone -functional polysaccharide.

[0064] In another example, the anode redox-active organic moiety may be viologen. Bromo-functional polysaccharides will react with l-methyl-[4,4’-bipyridin]-l-ium to form viologen-functional polysaccharide.

[0065] Thus, provided herein is an anode active material comprising a polysaccharide functionalised with one or more anode redox-active organic moiety.

[0066] For an all-polymer battery the electrolyte may be salt water. For example, the electrolyte may be a salt solution having a salt concentration of from about IM to about 3M. For example, the electrolyte may be 3M NaCl.

[0067] For a hybrid battery the electrolyte may be and aqueous zinc chloride solution or an aqueous zinc perchlorate solution. For example, the electrolyte may be a 2M zinc perchlorate solution.

[0068] Polymer batteries can be assembled by preparing cathode and anode electrodes from active materials derived from chemically modified polysaccharides, such as cellulose, starch, chitosan, or alginate. The cathode active material, functionalized with redox-active organic groups (for example, nitroxide radicals or phenothiazine), is mixed with a conductive carbon additive, such as carbon nanotubes or carbon black, to form a composite electrode. Similarly, the anode active material, functionalized with redox-active organic groups (such as viologen or anthraquinone), or alternatively metallic zinc or magnesium, is combined with a conductive carbon additive to form the anode electrode. The prepared electrodes are applied to suitable substrates and dried under controlled conditions. The cathode and anode electrodes are then positioned with a separator between them, and an electrolytesolution — such as salt water for all-polymer batteries, or aqueous zinc chloride or perchlorate solution for hybrid batteries — is introduced to facilitate ionic conductivity. The components are assembled into a rechargeable electrochemical cell, which may be configured in various formats, including Swagelok-type or pouch-type cells, to optimize performance and accommodate specific application requirements.

[0069] The conductive carbon additive can be any suitable carbon based material that is conductive. For example, the conductive carbon additive may comprise carbon nanotubes. In another example, the conductive carbon additive may comprise carbon black. Multi-walled carbon nanotubes (MWCNTs) can be used as the conductive carbon additive. Suitable MWCNTs are commercially available. Carbon black N234 can also be used as the conductive carbon additive. Suitable carbon black N234 is commercially available commercially.

[0070] Thus, provided herein is a method for assembling a polymer battery. The method comprises providing a cathode electrode comprising a cathode active material mixed with carbon, said cathode active material comprising a polysaccharide functionalised with one or more cathode redox -active organic moiety. The method also comprises providing an anode electrode comprising metallic zinc, magnesium or an anode active material mixed with carbon, said anode active material comprising a polysaccharide functionalised with one or more anode redox-active organic moiety. The cathode electrode and the anode electrode are then combined with a salt water-based electrolyte and the components are assembled into a rechargeable electrochemical cell.

[0071] The innovative electrode materials and batteries described herein will (i) not rely on petrochemicals, (ii) not generate micro- and nano-plastic pollution to the environment, and (iii) enable batteries to use salt water as electrolytes for easy fabrication and safe operation.EXAMPLES

[0072] Example 1 - Synthesis of a cellulose graft oligo TEMPO active polymer (Cellulose-g- oligo(TEMPO acrylate) (P3)) cathode active material

[0073] A process for the synthesis of Cellulose-g-oligo(TEMPO acrylate) P3 through Cu(0) -mediated reversible-deactivation radical polymerization using bromine -functional cellulose Pl as macroinitiator, followed by the oxidation of Cellulose-g-oligo(TMPA) P2 is shown in Scheme 1.Scheme 1

[0074] Synthesis of cellulose-bromine initiator (Cellulose-Br) (Pl)

[0075] In a 250 mL round-botom flask, dried cellulose (1.0 g, 6.17 mmol) was suspended in 40 mL of anhydrous DMAc and stirred at 130 °C for 2 hours. Afterward, the slurry was cooled to 100 °C, and 2.0 g of LiCl was added to the mixture, followed by continued stirring to form a homogeneous solution. The solution was then cooled in an ice bath, and 2 -bromopropionyl bromide (BPB) (3.9 mL, 37 mmol, and 6 equivalents) was slowly added to the cellulose solution with vigorous stirring. After all BPB was added, the mixture was maintained in an ice bath for another hour. Finally, the mixture was allowed to warm to room temperature and stirred for an additional 36 hours. After that, the reaction mixture was poured into 400 mL of deionized water, and a white product was separated by vacuum filtration. The isolated product was further purified by washing with fresh deionized water (3 x 300 mL) before being freeze-dried to remove residual water (1.51 g, 43%). The second esterification was performed to increase the conversion. To a 100 mL round-botom flask, 0.5 g of cellulose-Br (from the initial acylation) was dissolved in 20 mL of anhydrous N-methylpyrrolidone. This solution was then treated with 1.5 mL of BPB slowly in an ice bath while stirring. The reaction mixture was continuously stirred for 36 hours at room temperature. Afterwards, the mixture was precipitated in deionized water, and the solid was separated by vacuum filtration. The final product was soluble in acetone; therefore, further purification involved dissolving the product in acetone and precipitating it in DI water (repeated twice) before freeze-drying (yield: 0.76 g).

[0076] Synthesis of Cellulose-g-oligo(TMPA) (P2)

[0077] The cellulose-Br initiator Pl (0.84 mmol, 0.48 g) was dissolved in approximately 16 mL of oxygen-free, dry DMSO in a Schlenk tube. Separately, the TMPA monomer (15 equivalents, 12.6 mmol, 2.66 g) was dissolved in 6 mL of oxygen-free, dry acetone. Then, MeeTREN (2.55 equivalents, 2. 14 mmol, 0.43 mL), a catalytic amount of Cu(II)Br2 / Me6TREN (0.15 equivalents, 0. 126 mmol, 0.06 g), and the monomer solution were added to the cellulose-Br initiator solution. The entire mixture waspurged with nitrogen for over 30 minutes again to remove any residual oxygen before adding the polished copper wire. The reaction was complete after 3 hours at 25 °C. The viscous solution was then added to 300 mL of deionized water to precipitate the product, which was washed three times with 100 mL of deionized water each. Finally, it was dried in a vacuum oven at 70 °C (yield: 2.2 g).

[0078] Synthesis of Cellulose-g-oligo(TEMPO acrylate) (P3) by oxidation ofP2

[0079] Cellulose-g-oligo(TMPA) (P2) (0.401 mmol, 1.5 g) was suspended in 25 mL of DCM. Then, 2 g of m-CPBA (2 eq per TEMPO precursor) was added to the above mixture in portions, with vigorous stirring in an ice bath. After adding all the m-CPBA. the mixture was stirred for 3 hours at room temperature. Finally, the red-coloured product was separated by centrifugation and purified by thoroughly washing with DCM three times, then with DEE twice, before being dried in a vacuum oven at 50 °C (yield: 1.18 g).

[0080] Chemical characterizations of synthesised cathode active materials

[0081] The synthesised products (Pl, P2 and P3) were characterised using spectroscopic techniques such as ATR-IR, NMR and EPR.

[0082] The resulting Pl was first characterized by attenuated total reflectance infrared (ATR-IR) spectroscopy (Figure 1). Compared with pristine cellulose, Pl showed a new peak at 1744 cm1, indicating the typical C=O stretching vibration. The hydroxyl peak at 3320 cm'1for the cellulose disappeared in the Pl polymer, suggesting high conversion due to the two-step esterification process (Figure 1). ’H nuclear magnetic resonance (NMR) of Pl, displayed in Figure 1, showed methyl protons at 1.55 ppm to 1.75 ppm, with three peaks, attributed to the slightly different environments of the three substitutions. Compared to the Pl, NMR of P2 showed new peaks at 1. 16 ppm, 1.79 ppm, 2.20 ppm, and 5.05 ppm, which were attributed to the 2,2,6,6-tetramethylpiperidine groups (Figure 3). The diminishing proton signals (from 3.5 ppm to 5 ppm) for the cellulose units in the P2 NMR result from the significant suppression of those proton signals by the polymer chains grafted onto the cellulose backbone. The ATR- IR of P2 and P3 showed enhanced CH, peak at 2920 cm1, C=O stretching shifting to 1726 cm1, and C— N stretching at 1180 cm'1from piperidine. For P3, strong signals at 1360 cm'1and 1460 cm'1were ascribed to N— O* after the oxidation reaction (Figure 2). The radical content in P3 was quantified by electron paramagnetic resonance (EPR) in the solid state. Figure 4 (insets) shows the EPR spectrum of P3, and the insets show the standard spectra and the calibration curve based on solid 4-acetamido- TEMPO (ACT). The calculated theoretical capacity was 100 mAh g1based on the radical molar mass of 267 g mol1(using Eq. 1), as determined by EPR.

[0083] F * n Eq. - 1Specific capacity — -Mw * 3.6

[0084] Where F is Faraday constant, n is number of electrons transferred (in redox reaction), and Mw is Molecular weight (per active group).

[0085] Example 2 - Synthesis of a cellulose graft anthraquinone active polymer (cellulose-g- anthraquinone (P4) anode active material

[0086] A process for the synthesis of cellulose -g -anthraquinone P4 is shown in Scheme 2.Scheme 2

[0087] In a 250 ml round-bottom flask equipped with a stirrer bar, 3.52 g (13.95 mmol) of anthraquinone -2 -carboxylic acid was mixed with excess thionyl chloride (50 ml) under a N2 environment. Then, the mixture was refluxed at 80 °C for 6 hours. After the designated time, the product was isolated by removing excess SOCI2 via distillation under reduced pressure, and the product (light brown colour) was directly used for the next step. The cellulose solution was prepared by mixing dried cellulose (0.5 g, 3.1 mmol) with 20 m of anhydrous DMAc and stirring at 130 °C for 2 hours in a 100 m round-bottom flask. After that, the slurry was allowed to cool, and 1 g of LiCl was added to the mixture when the temperature reached 100 °C, and the mixture was stirred to obtain a homogeneous solution. Then, the cellulose solution was added to previously prepared anthraquinone -2 -carbonyl chloride (mixed with 20 ml anhydrous DMAc before adding cellulose), and the entire mixture was stirred at 70 °C overnight. After the designated time, the reaction mixture was centrifuged, and the supernatant was combined with ethanol to precipitate the product. The separated product was purified by redissolving in DMF and precipitating in an ethanol / DMF (2: 1) mixture three times (1 g). The product was confirmed withXH NMR and ATR-IR.

[0088] Chemical characterizations of Cellulose-g-anthraquinone (P4)

[0089] The cellulose-g-anthraquinone (P4) product was characterised by ATR-IR and 1H-NMR techniques. According to the ATR-IR spectrum of P4 (Figure 5), the peaks at 1680 cm'1and 1580 cm'1represent the carbonyl group and aromatic C=C bond, respectively, in the anthraquinone moieties. In addition, the peak at 1730 cm'1denotes the C=O bond in the ester linkage of anthraquinone graftedcellulose, while 1160 cm'1represents the C-O-C bond in the cellulose backbone. Specifically, the stretching vibration of the hydroxyl groups in cellulose at 3330 cm'1in the cellulose spectrum has almost disappeared in the ATR-IR spectrum of P4, indicating the higher conversion of the product. The1H-N M R of the P4 was obtained using DMSO-de as the solvent. The spectrum shows a broader peak between 8.5 ppm and 7 ppm, which results from aromatic protons (g-j in Figure 6) in the polymer-graft anthraquinone groups. In addition, the diminished broader peak in theNMR confirms the protons of the cellulose backbone (a-f in Figure 6 inset). The UV-Vis absorption spectrum of P4 was recorded in DMSO at room temperature (Figure 7). The spectrum shows a broad absorption peak around 330 nm, specific to the transition involving the non-bonding electrons of the carbonyl groups of the anthraquinone moieties on the polymer backbone. In addition, UV-Vis spectroscopy was used to quantify the degree of substitution of the P4 polymer. In this case, anthraquinone -2 -carboxylic acid was used as a standard to construct the calibration curve (Figure 7 insets), which was used to calculate the molecular weight of P4 per anthraquinone (360 g mol1). The degree of substitution was calculated as 1.3 based on the obtained molecular weight per anthraquinone.

[0090] Example 3 - All polymer battery fabrication and morphology analysis of electrode materials

[0091] Electrode preparation and battery assembly

[0092] Cathode and anode electrode composites were prepared using cellulose-g-oligo(TEMPO acrylate) (P3) and cellulose-g-anthraquinone (P4), respectively. The polymers were ground with carbon additives (multi-walled carbon nanotubes (MWCNT) or N234) at a 50:50 ratio, using anhydrous NMP as the solvent. This grinding was performed in a mortar for about one hour to obtain a properly blended slurry.

[0093] Electrode preparation for Swagelok-type batteries

[0094] Then, the prepared electrode slurries were applied as an even layer on pre -weighted circularshaped carbon felts (diameter 1 cm). The cathode active material was used as a limited active material. Therefore, the mass of cathode active material was maintained below the mass of the anode active material. The areal mass loading for cathodes was about 2 mg cm'2to 6 mg cm'2, and the mass of the anode active material was approximately twice that of the cathode material.

[0095] Electrode preparation for pouch-type batteries

[0096] The prepared electrode slurries were applied as an even layer on pre-weighted square-shaped carbon felts (3.5 cm x 4 cm). The areal mass loading of cathode materials was about 100 mg cm'2to 200 mg cm'2, and the anode active material was approximately twice that of the cathode.

[0097] Finally, all electrodes were dried in a vacuum oven at 80 °C overnight.

[0098] Battery assembly

[0099] Battery assembly was performed in air or in a nitrogen-fdled glove box, with glass fibre as the separator, and the electrolyte was 3 M NaCl. The Swagelok-type batteries were assembled in the Swagelok-type housing. The pouch batteries were assembled in a laminated paper pouch and platinum (Pt) metal strips were used as current collectors.

[0100] Morphological analysis of electrode composites (P3 and P4 with different carbon additives)

[0101] In the electrode composite, each redox-active polymer material was mixed with MWCNT or N234 in a 50:50 ratio using NMP solvent. Both SEM images of P3 with MWCNT and N234 (Figure 8 a & b) reveal that the active polymer material is uniformly mixed with both carbon additives. Specifically, MWCNT forms a network wrapped with P3, resulting in a porous composite morphology, and this higher surface area provides a continuous conductive pathway. In contrast, the active P3 / N234 composite exhibits a denser, more closely packed morphology of the polymer and carbon particles, resulting in a significant enhancement in the conductivity. However, aggregation areas in the SEM images of the cathode composite may result from the insolubility of the P3 in NMP. Comparatively, the SEM of P4 with MWCNT and N234 (Figure 8 c & d) reveal smooth and low aggregation composites. This is attributed to the solubility of P4 in NMP solvent.

[0102] Example 4 - Metal-polymer hybrid battery performance (with zinc (Zn) and synthesised active polymers)

[0103] The performance of cellulose-g-oligo(TEMPO acrylate) P3 and cellulose-g -anthraquinone P4 active materials was analysed in a metal-polymer hybrid battery system by combining with zinc metal before they were used in all-polymer battery systems.

[0104] Performance ofZn\P3 hybrid battery (Swagelok type)

[0105] In this hybrid battery, cellulose-g -oligo(TEMPO acrylate) P3 serves as the cathode, zinc serves as the anode, and 2M zinc perchlorate (Zn(C104)2) serves as the electrolyte.

[0106] Cyclic voltammetry (CV) analysis is fundamental for understanding the redox activity of redoxactive materials. The CV of the Zn||P3 (Figure 9) exhibits reversible peaks at 1.53 V vs Zn2+ / Zn, representing the oxidation of TEMPO to TEMPO Oxoammonium cation) and the reduction of TEMPO back to TEMPO. The nearly equal anodic peak current (Ipa = 1 mA) and cathodic peak current (Ipc = 1.1mA) indicate that the redox reaction of TEMPO in the P3 polymer is highly reversible, and no side reactions are involved. The galvanostatic charge -discharge cycling of ZnllP3 reveals a 1.5 V working potential and a higher discharge capacity of 72 mAh g’1(Figure 11), which is approximately 70% of the specific capacity of cellulose-PTEMPO (100 mAh g’1). In addition, initial capacities have been reduced by only 5% over the first 200 cycles, with >98% coulombic efficiency (Figure 10), indicating greater stability of the active material and very low side reactions.

[0107] Performance of a Zn\P4 hybrid battery (Swagelok type)

[0108] In this hybrid battery, cellulose-g -anthraquinone P4 serves as the cathode, zinc serves as the anode, and 2M zinc perchlorate (Zn(ClC>4)2) serves as the electrolyte.

[0109] The CV of the Zn||P4 battery (Figure 12) also shows well-defined reversibility at 0.58 V vs Zn2+ / Zn, which is associated with the redox reaction between the anthraquinone0(AQ°) and anthraquinone’ (AQ’) / anthraquinone2’ (AQ2). In addition, approximately similar anodic and cathodic peak currents, respectively 1.1 mA and 1.2 mA, prove a clean redox reaction of anthraquinone in the Cellulose- g-anthraquinone active material. By considering the two-electron transfer redox activity of anthraquinone, the specific capacity of P4 can be calculated as 148 mAh g’1(using Eq. 1, based on the per anthraquinone molecular weight of 360 g mol’1). The Zn||P4 battery delivered an initial capacity of 78 mAh g’1, approximately half its full capacity. The working potential was recorded as 0.58 V (Figure 14). The low initial capacity of the Zn||P4 battery can be attributed to the lower utilisation of the P4 active material during battery operation. The long -cycle performance shows that capacity retention is 86% (Figure 13) after 200 cycles, which is slightly lower than that of the Zn||P3 battery system under the same conditions.

[0110] Example 5 - All polymer battery (PPP 3) performance

[0111] Swagelok-type all polymer battery (PPP 3) performance

[0112] Initially, CV was performed on the all-polymer battery to evaluate the electrochemical redox activity of the active compounds during battery operation. The CV of the all-polymer battery (Figure 15) clearly exhibits two reversible peaks at 1.39 V (anodic peak potential, Eap) and at 1.34 V (cathodic peak potential, Ecp), representing oxidation and reduction reactions, respectively. Based on the peak oxidation and reduction potential values, the overall redox potential (E1 / 2) can be obtained as 1.36 V, indicating the working voltage of our all-polymer battery. According to the rate performance, the battery delivered a maximum discharge capacity of about 90 mAh g’1at 0.14 A / g (Figure 16 and 17). The discharge capacity gradually decreased with increasing current density, reaching only 70 mAh g’1at 1.67 A g’1, indicating reduced kinetics at higher current densities. The long cycle performance was analysed at moderate current density (0.21 A g’1) (Figure 18 and 19). The initial discharge capacity of our battery was 90 mAh g’1,which is about 90% of the calculated specific capacity of the limited active material (Cellulose -g- oligo(TEMPO acrylate)) in this battery. After 300 cycles, our battery recorded 66 mAh g1discharge capacity, equal to 73% capacity retention, which equals 0.09% capacity loss per cycle. Finally, our allpolymer batteries can deliver the energy density of 85 Wh kg1to 114 Wh kg1with a power density of 120 Wh kg1to 2000 W kg1(Figure 20).

[0113] Pouch battery performance

[0114] After the small-scale batteries (Swagelok-type), the performance of the large-scale battery was analysed by increasing the limited active material loading to 15 mg cm'2. In the cycling performance, our pouch battery delivered about 80 mAh g1discharge capacity and reported about 52 mAh g1after 100 cycles at 0. 1 A / g with >95% coulombic efficiency (Figure 21 and 22). Initially, our pouch battery delivered an energy density of about 95 Wh kg-1 at 0.1 A / g. We also demonstrate the practical benefits of our cellulose-based redox-active polymer battery by lighting an LED (Figure 23).

[0115] Example 6 - Synthesis of a TEMPO cellulose-based cathode active material via a quaternization process

[0116] Synthesis of Cl-cellulose (P5)Cellulose Chloroacetyl chloride Cl-celiulose (P5)

[0117] To a 250 ml round bottom flask equipped with a magnetic stirring bar, pre -dried cellulose (12.33 mmol, 2 g) (cellulose was dried at 75 °C for 24 hours) was suspended in 40 ml of anhydrous DMAc and stirred at 130 °C for 2 hours. After that, the slurry was allowed to cool to 100 °C to add Li Cl (4 g), and the mixture was stirred while it was cooling down to RT. Then, chloroacetyl chloride (6 eq, 73.98 mmol, 8.356 g) was added dropwise to the cellulose solution at 0 °C while stirring vigorously under the N2 environment. After adding all chloroacetyl chloride, the reaction mixture was maintained at 0 °C for about another 1 hour and continued at RT for 36 hours.

[0118] After the designated time, the reaction mixture was added to about 600 ml of DI water (slightly basic), and the product was separated via vacuum filtration. Then, the obtained product was washed with fresh cold water several times (300 ml x 3) before being subjected to a freeze-drying process to remove the residue water.

[0119] Synthesis ofN,N-dimethyl-4-amine TEMPO (P6)4-oxo TEMPO N,N-dimethyi-4-amine TEMPO (P6)

[0120] In a 100ml round botom flask equipped with a stirrer bar, 4-oxo-TEMPO (17.63 mmol, 3 g) was dissolved in about 30 ml of absolute (dry) MeOH, followed by adding of dimethyl hydrochloride (10 eq, 176.26 mmol, 14.4 g) and the mixture was stirred to total dissolve over 30 minutes. After that, sodium cyanoborohydride (0.72 eq, 12.7 mmol, 0.8 g) was dissolved in about 10 ml of dry MeOH separately and added to the reaction mixture slowly. The Reaction mixture was continuously stirred for five days @ RT in the dark. After 5 days, the reaction was stopped, liquid part of the mixture (with product) was separated via centrifuge and concentrated under reduced pressure conditions (@ low temperature). The obtained product was dissolved in about 50 ml of DI water, and a solid KOH pellet was added to the mixture to increase pH (>12). After that, the product was extracted into DEE (60 ml x 5) and collected DEE portions were dried with any. MgSO4 before separating the product under reduced pressure conditions.

[0121] Synthesis ofTEMPO-cellulose (P7)Ci-celluiose (P5) N,N-dimethy!-4- TEMPO-ceiiulose (P7) amine TEMPO (P6) (cathode active materiai)

[0122] To a 25 ml glass vial, Cl-cellulose (0.13 mmol, 0.05 g) was dissolved in 1.5 ml of dry DMF, and N, N-dimethyl-4-amine TEMPO (6 eq, 0.77 mmol, 0.153 g) was dissolved in 1.5 ml of dry DMF separately in a 25 ml two neck round botom flask. Then, Cl-cellulose solution was added to the dimethyl TEMPO solution over one hour at 60 °C. After adding all cellulose, the mixture was stirred for another three hours at 55 °C. After the designated time, the product was separated by precipitating in DEE and washed with the same solvent several times (25 ml x 4) before being dried in a vacuum oven.

[0123] Example 7 - Synthesis of a viologen-cellulose anode active material

[0124] Synthesis ofMe-viologen (P9)4,4-Bipyridine iodomethane Me-Vio!ogen (P8) Me-Viologen (P9)

[0125] In a 100 ml round botom flask equipped with a magnetic stirrer bar, 4,4-Biperidine (19.21 mmol, 3 g) was dissolved in 50 ml of CHCU. Then, separately, Methyl iodide (1.1 eq, 21.13 mmol, 3 g) was dissolved in 7 ml of CHCU and added to the bipyridine solution dropwise while refluxing the system at 55 °C over 1 hour. After adding all CH3I, the mixture was refluxed for another 22 hours under the dark at 55 °C. After the designated time, the yellow colour product (P8) was separated via filtration and washed with ethyl acetate several times (80 ml x3) before being dried under vacuum.

[0126] After that, 3.9 g of P8 was subjected to an ion exchange process by dissolving in about 6 ml of DI water and transferring through the CF ion exchange resin. Finally, the ion-exchanged product (P9) was separated by freeze-drying.

[0127] Synthesis of Viologen-cellulose (P10)Cl-cellulose (P5) Me- Viologen (P9) Viologen-cellulose (PIO) (anode active material)

[0128] In a 25 ml glass vial, Cl-cellulose (0.51 mmol, 0.2 g) was dissolved in 6 ml of dry DMF, and Me-viologen (4.5eq, 2.3 mmol, 0.475 g) was dissolved in 30 ml of dry DMF separately in a 100 ml two neck round botom flask. Then, Cl-cellulose solution was added to the viologen solution slowly (over 1 hour) at 60 °C, and the reaction mixture was stirred continuously for 20 hours at the same temperature. At the end of the designated time, the product was separated by precipitating in a DEE / EtOH (3: 1) mixture, and the separated product was washed with pure EtOH overnight. After several washes with EtOH, the product was dried in a vacuum.

[0129] Example 8 - Synthesis of a TEMPO-alginate cathode active material

[0130] Synthesis procedure for Alginate-based cathode active material (P13)Alginic acid TEMPO-alginate (P13)(cathode active material)

[0131] In a 50ml round bottom flask equipped with a stirrer bar, alginic acid (1.14 mmol, 0.2 g) was mixed with about 12 ml of DI water and stirred for about 2 hours. Then, the solution of EDC.HCI (2 eq, 2.27 mmol, 0.436 g) and NHS (2 eq, 2.27 mmol, 0.261 g) (in about 1 ml of DI water) were prepared separately. This mixture was added slowly to the alginic acid mixture at 0 °C. After stirring for 2 hours, the pH of the mixture was adjusted to 5-6 with NaOH before adding amine TEMPO (2 eq, 2.27 mmol, 0.389 g). The reaction mixture was stirred for about 40 hours, and after 40 hours, the same portions of EDC.HCI (2eq) / NHS (2eq) and NH2-TEMPO (2eq) were added, and the reaction was continued for 4 to 6 days. After the designated time, the reaction mixture was purified via dialysis against DI water for two days (water was changed rapidly), and the product was separated by freeze-drying.

[0132] The present disclosure may be characterised according to any one or more of the following statements.

[0133] Statement 1: A biomass-based all-polymer battery comprising: a cathode material derived from chemically modified polysaccharides selected from cellulose, starch, chitosan, or alginate, functionalized with redox-active organic groups, including nitroxide radicals and phenothiazine; and an anode material derived from chemically modified polysaccharides functionalized with selected redox-active organic groups, such as viologen or anthraquinone:

[0134] Statement 2: An electrolyte solution utilizing salt water (2M NaCl), enabling environmentally safe and low-cost fabrication and operation.

[0135] Statement 3: A hybrid battery comprising: a cathode material derived from biomass, chemically modified with redox-active groups, including TEMPO-cellulose or TEMPO-alginate;a metallic zinc or magnesium anode; and an electrolyte solution designed for hybrid compatibility, including or aqueous zinc chloride or perchlorate solutions.

[0136] The biomass-based all-polymer battery of statement 1, wherein the cathode active material isTEMPO-cellulose synthesized through selective chemical reactions involving NaOH / urea treatment and nitroxide functionalization or radical polymerization to graft oligopoly (TEMPO).

[0137] The biomass-based all-polymer battery of statement 1, wherein the anode active material is anthraquinone-cellulose synthesized through selective chlorination and carbonyl chloride reaction.

[0138] The hybrid battery of statement 2, wherein the cathode material is TEMPO-alginate, synthesized via amide coupling reactions in aqueous media.

[0139] The battery of statement 1 or 2, wherein the electrodes are optimized for electrochemical performance with specific capacities of 172 mAh / g for cathodes and 259 mAh / g for anodes.

[0140] The battery of statement 1 or 2, wherein the electrolyte is selected based on environmental compatibility and ionic conductivity, using salt water as the primary solvent.

[0141] Statement 4: A method of fabricating biomass -derived cathode materials for use in batteries, comprising: modifying polysaccharides such as cellulose or alginate with redox-active organic functionalities, including TEMPO, phenothiazine, anthraquinone or viologen; performing chemical synthesis steps including ion exchange, esterification, or amide coupling, radical polymerization; and incorporating the modified materials into electrode structures.

[0142] Statement 5 : A method for assembling a biomass-based all-polymer battery, comprising: preparing cathode and anode active materials derived from modified polysaccharides; preparing electrode composite by mixing polysaccharide electrode active materials with carbon additives, including carbon nanotubes or carbon black; combining the electrodes with a salt water-based electrolyte; and assembling the components into a rechargeable electrochemical cell optimized for safe and sustainable energy storage.

[0143] Statement 6: A method of improving the environmental impact of batteries, comprising: replacing petrochemical-based materials with biomass-derived polysaccharides for electrodes;and ensuring the end-of-life degradation of battery components avoids micro- and nanoplastic pollution.

[0144] The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that such prior art forms part of the common general knowledge.

[0145] It will be understood that the terms “comprise” and “include” and any of their derivatives (e.g. comprises, comprising, includes, including) as used in this specification, and the claims that follow, is to be taken to be inclusive of features to which the term refers, and is not meant to exclude the presence of any additional features unless otherwise stated or implied.

[0146] In some cases, a single embodiment may, for succinctness and / or to assist in understanding the scope of the disclosure, combine multiple features. It is to be understood that in such a case, these multiple features may be provided separately (in separate embodiments), or in any other suitable combination. Alternatively, where separate features are described in separate embodiments, these separate features may be combined into a single embodiment unless otherwise stated or implied. This also applies to the claims which can be recombined in any combination. That is a claim may be amended to include a feature defined in any other claim. Further a phrase referring to “at least one of’ a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c.

[0147] It will be appreciated by those skilled in the art that the disclosure is not restricted in its use to the particular application or applications described. Neither is the present disclosure restricted in its preferred embodiment with regard to the particular elements and / or features described or depicted herein. It will be appreciated that the disclosure is not limited to the embodiment or embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the scope as set forth and defined by the following claims.

Claims

CLAIMS1. A polymer batery comprising : a cathode comprising a cathode active material comprising a polysaccharide functionalised with one or more cathode redox-active organic moiety; an anode comprising metallic zinc, magnesium or an anode active material comprising a polysaccharide functionalised with one or more anode redox-active organic moiety; and an electrolyte solution.

2. The polymer batery of claim 1, wherein the polysaccharide of the cathode active material and / or the anode active material is selected from the group consisting of cellulose, starch, chitin, chitosan, alginate, and derivatives of any of the aforementioned.

3. The polymer batery of either claim 1 or claim 2, wherein the cathode redox-active organic moiety is selected from the group consisting of organic nitroxide radicals, phenothiazine, 2,5-di- substituted 1,4-dimethoxybenzene, and derivatives of any of the aforementioned.

4. The polymer batery of any one of claims 1 to 3, wherein the anode redox-active organic moiety is selected from the group consisting of viologen, anthraquinone, azobenzene, phenazine, and derivatives of any of the aforementioned.

5. The polymer batery of any one of claims 1 to 4, wherein the polysaccharide of the cathode active material and / or the anode active material is cellulose.

6. The polymer batery of any one of claims 1 to 5, wherein the cathode redox-active organic moiety comprises 2,2,6,6-tetramethylpiperidinyloxy (TEMPO).

7. The polymer batery of any one of claims 1 to 6, wherein the cathode active material comprises TEMPO-cellulose.

8. The polymer batery of any one of claims 1 to 6, wherein the cathode active material is TEMPO- alginate.

9. The polymer batery of any one of claims 1 to 8, wherein the anode active material is anthraquinone-cellulose.

10. The polymer batery of any one of claims 1 to 9, wherein the cathode and the anode are optimizedfor electrochemical performance with specific capacities of 172 mAh / g for cathodes and 259 mAh / g for anodes.

11. The polymer battery of any one of claims 1 to 10, wherein the anode active material comprises a polysaccharide functionalised with one or more anode redox-active organic moiety selected from the group consisting of viologen, anthraquinone, azobenzene, phenazine, and derivatives of any of the aforementioned and the electrolyte comprises salt water.

12. The polymer battery of any one of claims 1 to 10, wherein the anode comprises metallic zinc or magnesium and the electrolyte is selected from one or more of the group consisting of aqueous zinc chloride and perchlorate solution.

13. A cathode active material comprising a polysaccharide functionalised with one or more cathode redox-active organic moiety.

14. The cathode active material of claim 13, wherein the cathode redox-active organic moiety is selected from the group consisting of organic nitroxide radicals, phenothiazine, 2,5-di-substituted 1,4- dimethoxybenzene, and derivatives of any of the aforementioned.

15. An anode active material comprising a polysaccharide functionalised with one or more anode redox-active organic moiety.

16. The anode active material of claim 15, wherein the anode redox-active organic moiety is selected from the group consisting of viologen, anthraquinone, azobenzene, phenazine, and derivatives of any of the aforementioned.

17. A method of fabricating an electrode active material for use in batteries, comprising modifying a polysaccharide with one or more redox-active organic moiety.

18. The method of claim 17, wherein: the electrode active material is a cathode active material and the redox-active organic moiety is selected from the group consisting of organic nitroxide radicals, phenothiazine, 2,5-di-substituted 1,4- dimethoxybenzene, and derivatives of any of the aforementioned; or the electrode active material is an anode active material and the redox-active organic moiety is selected from the group consisting of viologen, anthraquinone, azobenzene, phenazine, and derivatives of any of the aforementioned.

19. A method for assembling a polymer battery, comprising:providing a cathode electrode comprising a cathode active material mixed with carbon, said cathode active material comprising a polysaccharide functionalised with one or more cathode redoxactive organic moiety; providing an anode electrode comprising metallic zinc, magnesium or an anode active material mixed with carbon, said anode active material comprising a polysaccharide functionalised with one or more anode redox-active organic moiety; combining the cathode electrodes and the anode electrode with a salt water-based electrolyte; and assembling a rechargeable electrochemical cell.

20. The method of claim 19, wherein the carbon is selected from one or more of the group consisting of carbon nanotubes and carbon black.

21. The method of either claim 19 or claim 20, wherein the cathode redox-active organic moiety is selected from the group consisting of organic nitroxide radicals, phenothiazine, 2,5-di-substituted 1,4- dimethoxybenzene, and derivatives of any of the aforementioned.

22. The method of any one of claims 19 to 21, wherein the anode redox-active organic moiety is selected from the group consisting of viologen, anthraquinone, azobenzene, phenazine, and derivatives of any of the aforementioned and the electrolyte comprises salt water.

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