WO2020115461A1 - Composition - Google Patents

Abstract

A composition comprising at least one thermoplastic or thermosetting polymer; at least one electrically conductive filler, and optionally at least one electrochemically active material; wherein the at least one electrically conductive filler is dispersed within the at least one thermoplastic or thermosetting polymer; and wherein the at least one thermoplastic or thermosetting polymer comprises a plurality of pores. Also, 3D printable filaments, or 3D printed articles comprising said composition, and processes for the preparation of said composition.

Description

COMPOSITION

INTRODUCTION

[001] The present invention relates to a composition which in one embodiment is used to prepare a 3D printable filament. In one embodiment, the composition can be 3D printed to provide advanced energy storage architectures, such as electrodes and complete electrochemcial cells.

BACKGROUND OF THE INVENTION

[002] With the environmental pressure to reduce fossil fuel usage and the ever-increasing demand upon energy consumption, there is currently a societal focus upon the development of innovative energy production/storage devices (Arico, Bruce et al., 2005; Zhang, Hou et al., 2016; Rowley-Neale, Foster et al., 2017). Consequently, there has been interest in the utilization and understanding of active materials (such as nanomaterials) as a platform for the continued improvement within the efficiency and effectiveness of new energy storage devices (Bruce, Scrosati et al., 2008).

[003] The understanding and application of these active materials has generally focused upon the utilisation of two-dimensional printing methods, such as blade coatings. However, research has now shifted to the incorporation of additive manufacturing (AM)/3D printing.

[004] AM/3D printing has attracted interest within the field of electrochemical energy storage due its ability to create large surface area structures, which can offer beneficial energy capabilities. The most utilised AM/3D printing techniques within the field of energy storage are typically based upon direct-writing technology, in which an active material dispersion is passed through a nozzle to create an intricate 3D structure (Ambrosi and Pumera, 2016). Generally, the performance of these devices can outperform that of their 2D counterparts.

[005] For example, Sun et al. (Sun, Wei et al., 2013) have utilised this direct-ink writing protocol to 3D print lithium-based active materials such as LUTisO^ (LTO) and UFeP0₄ (LFP), exhibiting specific capacities of 131 and 160 mAh g ¹ respectively.

[006] However, it should be noted that the creation of devices using the direct-ink writing methodology in many cases requires a complex post-production ex-situ step to solidify the device. For example, Garcia-Tunon et al. (Garcia-Tunon, Barg et al., 2015) incorporate the use of freezing with liquid nitrogen following extrusion/printing. Such approaches are extremely limited to simple geometries with a height of less than 1 mm, with in-situ curing being paramount to the structural integrity of the AM/3D printed objects.

[007] To exploit the full potential of AM/3D printing (i.e. large/complex geometries) one must consider alternatives to these AM/3D printing technologies. Fused deposition modelling (FDM) is one of the most popular additive manufacturing techniques as it allows a 3D printed object to be cured in-situ, without recourse to complex and time-consuming post-processing. One considerable challenge for FDM printing is the realisation of thermoplastic filaments with high filler (active material) content, which can be successfully printed. Generally, the currently commercially available 3D filaments contain low amounts of active materials within the 3D printable filaments, offering little applicability and ability to be useful in the field of electrochemistry.

[008] For example, Wei et al. have recently fabricated and partially characterised graphitic- based polylactic acid (PLA) and acrylonitrile-butadiene-styrene (ABS) conductive filaments with graphene loadings of up to 5.6 wt.%. In this case there is a very low amount of graphene that is incorporated into the filament as higher amounts result in a filament which is unable to be 3D printed due to aggregation of the graphene resulting in blocking of the nozzle.

[009] Recently, a commercially available graphene/poly(lactic) acid filament (PLA) was examined that could be successfully AM/3D printed into useful electrochemical geometries (Foster, Down et al., 2017). However, this filament only possessed approximately 8 wt. % active material (graphene) and has metal impurities which varies between batches.

[0010] The present invention seeks to provide alternative compositions, which may be suitable for 3D printing, and which have improved physicochemical and/or electrochemical properties and thus can be used to produce advanced energy storage architectures of large and complex geometries.

SUMMARY OF THE INVENTION

[0011] In a first aspect, the present invention relates to a composition comprising at least one thermoplastic or thermosetting polymer; at least one electrically conductive filler, and optionally at least one electrochemically active material; wherein the at least one electrically conductive filler is dispersed within the at least one thermoplastic or thermosetting polymer; and wherein the at least one thermoplastic or thermosetting polymer comprises a plurality of pores. [0012] In a second aspect, the present invention relates to a 3D printable filament comprising a composition according to the first aspect of the invention.

[0013] In a third aspect, the present invention relates to a 3D printed article comprising a composition according to the first aspect of the invention.

[0014] In a fourth aspect, the present invention relates to a composition comprising at least two polymers selected from a thermoplastic and/or a thermosetting polymer; at least one conductive filler, and optionally at least one electrochemically active material; wherein at least two polymers are immiscible with each other; and one of the polymers is selectively soluble in a given solvent over the other; and wherein the at least one conductive filler is dispersed within at least the polymer of relatively lower solubility in the solvent.

[0015] In a fifth aspect, the present invention relates to a process for preparing a composition according to the first aspect of the invention comprising (i) providing a first composition comprising at least one thermoplastic or thermosetting polymer; at least one conductive filler, and optionally at least one electrochemically active material; wherein the conductive filler is dispersed within the at least one thermoplastic or thermosetting polymer; and (ii) treating said first composition in a solvent to provide a second composition comprising a plurality of pores.

[0016] In a sixth aspect, the present invention relates to a process for preparing a composition according to the first aspect comprising (i) providing a first composition according to the fourth aspect of the invention and (ii) treating the first composition with a given solvent to provide a second composition comprising a plurality of pores.

[0017] In a seventh aspect, the present invention relates to a process for preparing a 3D printed article comprising 3D printing with a filament according to the second aspect of the invention.

[0018] In an eighth aspect, the present invention relates to an electrode comprising a composition according to the first aspect of the invention.

[0019] In a ninth aspect, the present invention relates to an electrochemical cell (battery) comprising a polymeric composition according to the first aspect of the invention or an electrode according to the eighth aspect of the invention, or a 3D printed article according to the third aspect of the invention. [0020] Preferred, suitable, and optional features of any one particular aspect of the present invention may also be preferred, suitable, and optional features of any other aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 shows TEM analysis of 20 wt.% graphene/PLA powders used to make the graphene/PLA filament.

[0022] Figure 2 shows SEM imaging of the graphene/PLA powders used to make the graphene/PLA filament (at 15 wt.% and 20 wt.% graphene loadings; A and B respectively).

[0023] Figure 3 shows TGA analysis of the graphene/PLA powders used to make the graphene/PLA filament.

[0024] Figure 4 shows Raman (inset) and Raman mapping of a 3D printed anode made from a 20 wt./% graphene/PLA filament. The Raman mapping is of the 2D band at ca. 2600cnr¹ (full width half maximum (FWHM): 74 cm ¹).

[0025] Figure 5 shows XPS spectra (A) and C 1s Region (B) of a 3D printed anode made from a 20 wt./% graphene/PLA filament.

[0026] Figure 6 shows SEM images of a 3D printed anode made from a 20 wt ./% graphene/PLA filament pre- and post-NaOH treatment and provides their respective charge- discharge profiles.

[0027] Figure 7 shows the TGA analysis of a 3D printed anode made from a 20 wt./% graphene/PLA filament after treatment with NaOH for 24 hours.

[0028] Figure 8 shows Ex situ ²³Na spin echo NMR spectra of a NaMnC>2 sample obtained under an external field of 200 MHz and at a spinning frequency of 60 kHz. The green bars identify sidebands.

[0029] Figure 9 shows XRD of the NaMn0₂ integrated into the 3D printed electrodes

[0030] Figure 10 shows a schematic illustration of the fabrication procedure of the AM/3D printed sodium-ion battery and photographs of the 3D printed electrodes.

[0031] Figure 11 shows cyclic voltammograms (CVs) of the compositional variation of 3D printed polymer-based electrodes, the 80% PVA/ABS [1 :1] / 20% Super P (black), 80% PVA/ABS [1 :1] / 20% Super P after sonication in deionised water for 4 hours to remove the PVA (red) , and 80% ABS / 20% PVA as a benchmark (green), all in 0.5M NaBF₄ in EMIBF₄.

[0032] Figure 12 shows the energy storage characteristics of the ink-based structure for increasing number of cycles, N,

[0033] Figure 13 shows the energy storage characteristics of the 3D printed energy storage architectures; (A) the polymer-based fully 3D printed structure for increasing number of cycles, N, (B) the current impact on the galvanostatic charge discharge capacity.

DETAILED DESCRIPTION OF THE INVENTION

[0034] In a first aspect, the present invention relates to a (electrically conductive) composition comprising at least one thermoplastic or thermosetting polymer; at least one electrically conductive filler, and optionally at least one electrochemically active material; wherein the at least one electrically conductive filler is dispersed within the at least one thermoplastic or thermosetting polymer; and wherein the at least one thermoplastic or thermosetting polymer comprises a plurality of pores.

[0035] In one embodiment, the electrically conductive filler is selected from at least one of a carbon species and a metal species. The filler may be in the form of a micro- or nano-material.

[0036] Examples of suitable carbon species include graphene, graphite, carbon black, Vulcan (registered trademark), acetylene black, carbon nanofiber, Ketjen black (registered trademark), carbon nanotube, super P, amorphous carbon, carbon nanohorn, carbon nanoballoon, hard carbon, and fullerene.

[0037] Suitably, the carbon species is selected from graphene, graphite, carbon black, carbon nanofiber and carbon nanotube. More suitably, the carbon species is selected from graphene, graphite and carbon black, or a combination thereof. In one embodiment, the graphite is exfoliated graphite.

[0038] In one embodiment, the electrically conductive filler is graphene or carbon black.

[0039] Examples of suitable metal species are aluminium, gold, silver, copper, iron, platinum, chromium, tin, indium, antimony, titanium, nickel, or oxides thereof.

[0040] In one embodiment the metal species is a metal nanowire. [0041] In one embodiment, the at least one electrically conductive filler is selected from graphene, graphite, carbon black, carbon nanoparticles (e.g. nanofibers, nanotubes), metal microparticles, metal nanoparticles (e.g. nanowires) or a combination thereof.

[0042] In one embodiment, the conductive filler is present at about 1 wt.% to about 40 wt.% of the composition. Suitably, about 10 wt.% to about 40%, more suitably about 15 wt.% to about 40 wt.%, more suitably about 20 wt.% to about 40 wt.%.

[0043] In another embodiment, the conductive filler is present at about 10 wt.% to about 35 wt.% of the composition. Suitably, about 10 wt.% to about 30%, more suitably about 10 wt.% to about 25 wt.%, more suitably about 10 wt.% to about 20 wt.%.

[0044] In another embodiment, the conductive filler is present at about 15 wt.% to about 40 wt.% of the composition. Suitably, about 15 wt.% to about 35%, more suitably about 15 wt.% to about 35 wt.%, more suitably about 15 wt.% to about 25 wt.%, more suitably about 15 wt.% to about 20 wt.%.

[0045] In one embodiment, the conductive filler is graphene and the graphene is present at about 5-25 wt.% of the composition, suitably about 10-25 wt.%, more suitably about 15-25 wt.%, more suitably about 20 wt.%.

[0046] In one embodiment, the conductive filler is graphite and the graphite is present at about 10-30 wt.% of the composition, suitably about 15-30 wt.%, more suitably about 20-30 wt.%, more suitably about 25 wt.%.

[0047] In one embodiment, the conductive filler is carbon black and the carbon black is present at about 5-25 wt.% of the composition, suitably about 10-25 wt.%, more suitably about 15-25 wt.%, more suitably about 20 wt.%.

[0048] Suitably, the conductive filler is uniformly dispersed in the at least one thermoplastic or thermosetting polymer.

[0049] As used herein the term“thermoplastic polymer” refers to a polymer which becomes pliable or mouldable above a certain temperature and solidifies upon cooling but can be remelted upon heating. Suitable thermoplastic polymers used herein have a melting temperature from about 60° C. to about 300° C, from about 80° C. to about 250° C, or from about 100° C. to about 250° C. Suitably, the thermoplastic polymer is one which is commonly comprised in commercial plastic products. Suitable thermoplastic polymers generally include polyolefins, polyesters, polyamides, copolymers thereof, and combinations thereof.

[0050] Examples of thermoplastic polymers include polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinylchloride (PVC), polyamideimide, polymethylmethacrylate (PMMA), polytetrafluoroethylene, polyethylene terephthalate (PET), natural rubber (NR), and polycarbonate (PC), polyvinylidene chloride (PVDC), acrylonitrile butadiene styrene (ABS), polyurethanes (PU).

[0051] As used herein the term“thermosetting polymer” refers to a polymer that is irreversibly cured and cannot be reworked upon reheating. Suitably, the thermosetting polymer is one commonly comprised in commercial plastic products.

[0052] In one embodiment, the polymer is selected from the group consisting of ABS (acrylonitrile butadiene styrene), Nylon (or polyamide), Acetate (or cellulose), PLA (poly lactic acid), terephthalate (such as PET polyethylene terephthalate), Acrylic (polymethylacrylate, Perspex, polymethylmethacrylate, PMMA), Polypropylene (or polypropene), Polystyrene (PS), PE (such as expanded- high impact-Polythene (or polyethene), Low density (LDPE) High density (HDPE)), PVC (polyvinyl chloride), Polychloroethene, and poly vinyl acetate (PVA).

[0053] In another embodiment, the polymer is selected from is selected from PLA, a polyamide (e.g. Nylon), ABS, HDPE and PVA or a mixture thereof. Suitably, the polymer is selected from is selected from PLA, ABS, HDPE and PVA or a mixture thereof. Suitably, the polymer comprises PLA and/or PVA.

[0054] In another embodiment, the polymer comprises a combination of PVA and ABS. Suitably, the polymer is essentially a combination of PVA and ABS. Suitably the polymer consists of a combination of PVA and ABS (e.g. about 1 :1 PVA: ABS). In one embodiment, the composition comprises up to about 30% PVA.

[0055] In one embodiment, the composition comprises at least one electrochemically active material. Suitably, the at least one electrochemically active material is dispersed within the at least one thermoplastic or thermosetting polymer.

[0056] The electrochemically active material absorbs and releases ions during charge and discharge and generates electric energy. Some electrochemically active materials are suitable for use at a positive electrode, having a constitution to absorb ions during discharge and release the ions during charge, while others are suitable for use at a negative electrode having a constitution to release ions during discharge and absorb the ions during charge. In some cases, the electrochemically active material may be suitable for use in a positive electrode or negative electrode.

[0057] In one embodiment, the electrochemically active material is selected from the group consisting of Li and oxides thereof, Na and oxides thereof, Si and oxides thereof, Se and oxides thereof, Sn and oxides thereof, Ge and oxides thereof, Sb and oxides thereof, Ti and oxides thereof, Zn and oxides thereof, Sn and oxides thereof, Co and oxides thereof, Fe and oxides thereof, Mn and oxides thereof, Ni and oxides thereof, Mo and oxides thereof, Cu and oxides thereof, a bimetallic compound or oxides thereof, a multi-metallic compound or oxides thereof, a sulfide material, a carbon material, or combinations thereof.

[0058] In certain cases, for instance, when the conductive filler is a carbon material (e.g. graphene) the conductive filler and the electrochemically active material may be the same.

[0059] In one embodiment, a lithium- or sodium-transition metal composite oxide is present as an electrochemically active material.

[0060] In another embodiment, the electrochemically active material is selected from lithium- transition metal composite oxides, a lithium-transition metal phosphate compound, and a lithium-transition metal sulfate compound, or a combination thereof. These materials are particularly suitable when the composition is used in a positive electrode.

[0061] In another embodiment, the electrochemically active material is selected from LiM^Ch, LiCoC>2, Li(Ni-Mn-Co)02 and NaMnC>2.

[0062] In one embodiment, the electrochemically active material is selected from a metal, such as Si or Sn; a metal oxide, such as TiO, T12O3, and T1O₂, or SiC>2, SiO, and SnC>2; a composite oxide of lithium and transition metal such as Lu_/sTisraCh or Li_/MnN; a Li-Pb alloy; a Li-AI alloy; Li; and a carbon material, such as graphite, graphene, carbon black, activated carbon, carbon nanoparticles, soft carbon, or hard carbon. These materials are particularly suitable when the composition is used in a negative electrode.

[0063] In one embodiment, the electrochemically active material(s) in the composition is present at between 1 to 40 wt.%, suitably about 10 wt.% to about 30%, more suitably about 15 wt.% to about 25 wt.%. [0064] In one embodiment, the composition has a conductivity of about 50 S/m or greater. Suitably, about 75 S/m or greater, more suitably about 100 S/m or greater.

[0065] In one embodiment, the composition has a conductivity of about 50 S/m to about 250 S/m. Suitably, about 50 S/m to about 200 S/m. More suitably about 50 S/m to about 150 S/m. More suitably about 100 S/m to about 150 S/m.

[0066] In one embodiment, the composition has a plurality of micropores and/or nanopores, suitably micropores.

[0067] In one embodiment, the composition is in the form of film, fibrous material, pellets, moulded article or filament. Suitably, the composition is in the form of a moulded article or a filament.

[0068] In a second aspect of the invention there is provided a 3D printable filament comprising, essentially consisting of, or consisting of a composition of the first aspect. The 3D printable filament may be prepared by methods known to the skilled person. For instance, the composition of the first aspect may be used in the form of granules, powder or pellets to form the 3D printable filament. The composition is extruded to provide the 3D printable filament.

[0069] In other aspects of the invention there is provided an electrode comprising, essentially consisting of, or consisting of the composition of the first aspect.

[0070] In another aspect, there is provided a 3D printed article comprising a composition of the first aspect. In one embodiment, the 3D printed article is an electrode, suitably, the electrode is an anode.

[0071] In another embodiment, the 3D printed article is an electrochemical cell (or battery).

[0072] In another aspect, there is provided an electrochemical cell (or battery) comprising a 3D printed electrode comprising a composition of the first aspect. Suitably, said electrochemical cell includes a positive electrode, a negative electrode, optionally a separator disposed between the positive and negative electrodes, and an electrolyte solution, wherein at least one of the electrodes is a 3D printed electrode according to the invention.

[0073] Any appropriate electrolyte solution that can conduct ions between the negative electrode and the positive electrode may be used in the battery. Skilled artisans are aware of the many non-aqueous liquid electrolyte solutions that may be employed in a battery, as well as how to manufacture or commercially acquire them. Examples of lithium salts that may be dissolved in an organic solvent to form the non-aqueous liquid electrolyte solution include UCIO4, UAICI4, Lil, LiBr, LiSCN, UBF₄, LiB(C₆H₅)4, UCF3SO3, LiN(CF₃S0₂)2 (LiTFSI), LiN(FS0₂)₂ (LiFSI), LiAsFe, UPF₆ UB(C₂0₄)2 (LiBOB), LiBF₂(C₂0₄) (LiODFB), L!PF₄(C20₄) (LiFOP), UNO3, and mixtures thereof. These and other similar lithium salts may be dissolved in a variety of organic solvents such as cyclic carbonates (ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate, fluoroethylene carbonate), linear carbonates (dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate (EMC)), aliphatic carboxylic esters (methyl formate, methyl acetate, methyl propionate), g-lactones (y-butyrolactone, y- valerolactone), chain structure ethers (1 ,2-dimethoxyethane, 1 ,2-diethoxyethane, ethoxymethoxyethane), cyclic ethers (tetrahydrofuran, 2-methyltetrahydrofuran), and mixtures thereof.

[0074] The skilled person would be aware of other components, which may be present in an electrochemical cell including a casing, gaskets, terminals, tabs, and any other desirable components or materials that may be situated between or around the negative electrode and the positive electrode for performance-related or other practical purposes.

[0075] In another aspect, the present invention relates to a composition comprising at least two polymers selected from a thermoplastic and/or a thermosetting polymer; at least one conductive filler, and optionally at least one electrochemically active material; wherein the two polymers are immiscible with each other; and one of the two polymers is selectively soluble in a given solvent over the other; and wherein the at least one conductive filler is dispersed within the polymer of relatively lower solubility in the solvent.

[0076] Both the conductive filler and the polymers may be selected from the embodiments described for the first aspect of the invention.

[0077] In one embodiment, the composition comprises two polymers, PVA and ABS and the given solvent is water.

[0078] In another aspect, the present invention relates to a process for preparing a composition as defined in the first aspect of the invention comprising (i) providing a first composition comprising at least one thermoplastic or thermosetting polymer; at least one conductive filler, and optionally at least one electrochemically active material; wherein the conductive filler is dispersed within the at least one thermoplastic or thermosetting polymer; and (ii) treating said first composition in a solvent to provide a second composition comprising a plurality of pores. [0079] Suitably, the solvent is aqueous sodium hydroxide.

[0080] In one embodiment, the first composition is treated with solvent for between 30 minutes and 24 hours at room temperature, suitably the solvent is aqueous sodium hydroxide.

[0081] In another aspect, the present invention relates to a process for preparing a composition according to the first aspect of the invention, comprising (i) providing a first composition as according to the fourth aspect of the invention (ii) treating the first composition with a given solvent to provide a second polymeric composition comprising a plurality of pores.

[0082] Suitably the given solvent is water. In one embodiment, the first composition is sonicated in water. Suitably, sonication is conducted for about 2 to about 12 hours, more suitably about 4 hours.

[0083] The invention will now be further described by virtue of the following numbered paragraphs:

1. A composition (suitable electrically conductive composition) comprising at least one thermoplastic or thermosetting polymer; at least one electrically conductive filler, and optionally at least one electrochemically active material;

wherein the at least one electrically conductive filler is dispersed within the at least one thermoplastic or thermosetting polymer; and

wherein the at least one thermoplastic or thermosetting polymer comprises a plurality of pores.

2. A composition according to paragraph 1 wherein the at least one electrically conductive filler is selected from a carbon or metal species, or a combination thereof.

3. A composition according to any one of the preceding paragraphs wherein the at least one electrically conductive filler is a carbon species selected from graphene, graphite, carbon black, Vulcan (registered trademark), acetylene black, carbon nanofiber, Ketjen black (registered trademark), carbon nanotube, carbon nanohorn, carbon nanoballoon, hard carbon, and fullerene, or combinations thereof.

4. A composition according to any one of the preceding paragraphs wherein the at least one electrically conductive filler is a carbon species selected the carbon species is selected from graphene, graphite, carbon black, carbon nanofiber and carbon nanotube, or combinations thereof. A composition according to any one of the preceding paragraphs wherein the at least one electrically conductive filler is selected from graphene, graphite and carbon black. A composition according to any one of the preceding paragraphs wherein the metal species is selected from aluminium, gold, silver, copper, iron, platinum, chromium, tin, indium, antimony, titanium, nickel, or oxides thereof. A composition according to any one of the preceding paragraphs wherein the content of the electrically conductive filler in the composition is between 1 to 40 wt.%, suitably about 10 wt.% to about 40%, more suitably about 15 wt.% to about 20 wt.%. A composition according to any one of the preceding paragraphs wherein the conductive filler is graphene and the graphene is present at about 5-25 wt.% of the composition, suitably about 10-25 wt.%, more suitably about 15-25 wt.%, more suitably about 20 wt.%. A composition according to any one of the preceding paragraphs wherein the conductive filler is graphite and the graphite is present at about 10-30 wt.% of the composition, suitably about 15-30 wt.%, more suitably about 20-30 wt.%, more suitably about 25 wt.%. A composition according to any one of the preceding paragraphs wherein the conductive filler is carbon black and the carbon black is present at about 5-25 wt.% of the composition, suitably about 10-25 wt.%, more suitably about 15-25 wt.%, more suitably about 20 wt.%. A composition according to any one of the preceding paragraphs which comprises at least one electrochemically active material. A composition according to paragraph 6 wherein the electrochemically active material is dispersed within the at least one thermoplastic or thermosetting polymer. A composition according to any one of the preceding paragraphs wherein the electrochemically active material is selected from the group consisting of Li and oxides thereof, Na and oxides thereof, Si and oxides thereof, Se and oxides thereof, Sn and oxides thereof, Ge and oxides thereof, Sb and oxides thereof, Ti and oxides thereof, Zn and oxides thereof, Sn and oxides thereof, Co and oxides thereof, Fe and oxides thereof, Mn and oxides thereof, Ni and oxides thereof, Mo and oxides thereof, Cu and oxides thereof, a bimetallic compound or oxides thereof, a multi-metallic compound or oxides thereof, a sulfide material, a carbon material, or combinations thereof. A composition according to any one of the preceding paragraphs wherein the electrochemically active material is selected from lithium-transition metal composite oxides, a lithium-transition metal phosphate compound, and a lithium-transition metal sulfate compound, or a combination thereof. A composition according to any one of the preceding paragraphs wherein the electrochemically active material is selected from a metal, such as Si or Sn; a metal oxide, such as TiO, T12O3, and TiC>2, or SiC>2, SiO, and SnC^; a composite oxide of lithium and transition metal such as LU_/sT sCL or L MnN; a Li-Pb alloy; a Li-AI alloy; Li; and a carbon material, such as graphite, graphene, carbon black, activated carbon, carbon nanoparticles, soft carbon, or hard carbon. A composition according to any one of the preceding paragraphs wherein the content of the electrochemically active material(s) in the composition is between 1 to 40 wt.%, suitably about 10 wt.% to about 30%, more suitably about 15 wt.% to about 25 wt.% A composition according to any one of the preceding paragraphs wherein the composition has a conductivity of about 50 S/m or greater, suitably, about 75 S/m or greater, more suitably about 100 S/m or greater. A composition according to any one of the preceding paragraphs wherein the polymer is selected from the group consisting of ABS (acrylonitrile butadiene styrene), Nylon (or polyamide), Acetate (or cellulose), PLA (poly lactic acid), terephthalate (such as PET polyethylene terephthalate), Acrylic (polymethylacrylate, Perspex, polymethylmethacrylate, PMMA), Polypropylene (or polypropene), Polystyrene (PS), PE (such as expanded- high impact-Polythene (or polyethene), Low density (LDPE) High density (HDPE)), PVC (polyvinyl chloride), Polychloroethene, and poly vinyl acetate (PVA). A composition according to any one of the preceding paragraphs wherein the polymer is selected from PLA, ABS, HDPE and PVA or a mixture thereof. A composition according to any one of the preceding paragraphs wherein the polymer consists of a combination of PVA and ABS (e.g. about 1 :1 PVA:ABS). A composition according to any one of the preceding paragraphs wherein the composition has a plurality of micropores and/or nanopores. A composition according to any one of the preceding paragraphs in the form of a film, pellets, fibrous material, moulded article or filament. A 3D printable filament comprising a composition according to any one of claims 1 to 22 A 3D printed article comprising a composition according to any one of paragraphs 1 to 22. A 3D printed article according to paragraph 24 wherein the article is an electrode. A 3D printed article according to paragraph 24 wherein the article is an electrochemical cell. An electrode comprising a composition according to any one of paragraphs 1 to 22. An electrochemical cell (battery) comprising a composition according to any one of paragraphs 1 to 22, an electrode according to paragraph 27, or a 3D printed article according to any one of paragraphs 24 and 25. A composition comprising at least two polymers selected from a thermoplastic and/or a thermosetting polymer; at least one conductive filler, and optionally at least one electrochemically active material;

wherein the at least polymers are immiscible with each other; and

one of the at least two polymers is selectively soluble in a given solvent over the other; and

wherein the at least one conductive filler is dispersed within the polymer of relatively lower solubility in the solvent. A composition according to paragraph 29 wherein the given solvent is water. A composition according to paragraph 29 wherein at least two polymers are PVA and ABS. 32. A process for preparing a composition according to any one of paragraphs 1 to 22 comprising

(i) providing a first composition comprising at least one thermoplastic or thermosetting polymer; at least one conductive filler, and optionally at least one electrochemically active material;

wherein the conductive filler is dispersed within the at least one thermoplastic or thermosetting polymer; and

(ii) treating said first composition in a solvent to provide a second composition comprising a plurality of pores.

33. A process according to paragraph 32 wherein the at least one thermoplastic or thermosetting polymer is PLA and the solvent is aqueous NaOH.

34. A process for preparing a composition according to any one of paragraphs 1 to 22 comprising

(i) providing a first composition as defined in any one of paragraphs 29 to 31 and

(ii) treating the first composition with a given solvent to provide a second polymeric composition comprising a plurality of pores.

35. A process for preparing a 3D printed article comprising 3D printing with a filament according to paragraph 23.

EXAMPLES

Example 1 - Li-ion anode for use in a Li-ion battery Materials and Methods

[0084] All chemicals used were obtained from Sigma-Aldrich at an analytical grade and were used without any further purification. All solutions were prepared with deionised water of resistivity not less than 18.2 MQ cm. Voltammetric measurements were carried out using an Autolab PGSTATIOO (Metrohm, The Netherlands) potentiostat.

[0085] Scanning electron microscope (SEM) images and surface element analysis were obtained with a JEOL JSM-5600LV model equipped with an energy-dispersive X-ray (EDX) microanalysis package. [0086] Raman spectroscopy was performed using a Renishaw InVia spectrometer with a confocal microscope (x 50 objective) spectrometer with an argon laser (514.3 nm excitation) at a very low laser power level (0.8 mW) to avoid any heating effects.

[0087] Thermogravimetric analysis (TGA) was conducted utilising a PerkinElmer TGA 4000. The PLA samples were subject to a gradual temperature increase of 10 °C per minute, over a range between 25 - 800 °C, under a flow of nitrogen (40 ml/min).

[0088] The X-ray photoelectron spectroscopy (XPS) data was acquired using a bespoke ultra-high vacuum system fitted with a Specs GmbH Focus 500 monochromated Al Ka X-ray source, Specs GmbH Phoibos 150 mm mean radius hemispherical analyser with 9-channeltron detection, and a Specs GmbH FG20 charge neutralising electron gun. Survey spectra were acquired over the binding energy range 1 100 - 0 eV using a pass energy of 50 eV and high-resolution scans were made over the C 1 s and O 1 s lines using a pass energy of 20 eV. Under these conditions the full width at half maximum of the Ag 3ds_/2 reference line is approximately 0.7 eV. In each case, the analysis was an area average over a region approximately 1.4 mm in diameter on the sample surface, using the 7 mm diameter aperture and lens magnification of x 5. The energy scale of the instrument is calibrated according to ISO 15472, and the intensity scale is calibrated using an in-house method traceable to the UK National Physical Laboratory. Data was quantified using Scofield cross sections corrected for the energy dependencies of the electron attenuation lengths and the instrument transmission. Data interpretation was carried out using CasaXPS software v2.3.16.

[0089] The heterogeneous electron transfer rate constant; k° ₀bs, were determined utilising the Nicholson method through the use of the following equation: y = k° _0bS[TTDnvFI(RT)f^V2 where y is the kinetic parameter, D is the diffusion coefficient, n is the number of electrons involved in the process, F is the Faraday constant, R is the universal gas constant and T is the temperature (Nicholson, 1965). The kinetic parameter, y, is tabulated as a function of AE_P (peak-to-peak separation) at a set temperature (298 K) for a one-step, one electron process with a transfer coefficient, a, equal to 0.5. The function of y (DE_R), which fits Nicholson's data, for practical usage (rather than producing a working curve) is given by: y = (-0.6288 + 0.0021X)/(1- 0.017X) where C= DE_R is used to determine y as a function of DE_R from the experimentally recorded voltammetry; from this, a plot of y against yxDnvFI{RT)}^{~ 1/2} allows the /r° _obs to be readily determined (Lavagnini, Antiochia et al., 2004). The heterogeneous electron transfer rate constants were calculated assuming a diffusion coefficient of 9 .10 x 10^~® cm² s^~1 for hexaarnmineruthenium (III) chloride (Banks, Compton et a/., 2004).

[0090] The 3D printed designs were fabricated using a ZMorph® printer (Warsaw, Poland) with a direct drive extruder at a temperature of 190 °C. The 3D printed designs were drawn via Fusion 360 (Autodesk, UK), to create a circular disc electrode with a range of diameters with a thickness of 1.0 mm.

Preparation and characterisation of additive manufacturing (AM)/3D printable filaments and 3D printed anode

[0091] AM/3D printable graphene / poly(lactic) acid (PLA) filaments were prepared by premixing graphene and PLA utilizing a facile solution based mixing step, briefly the graphene was dispersed within xylene and heated (under reflux) at 160 °C for 3 hours, the PLA was then added to the mixture and left for a further 3 hours. The resulting homogenous (solution phase) mixture then was then recrystallized within methanol, and left to dry (at 50 within a fan oven) until the xylene had evaporated. The resulting graphene-loaded PLA powder mix was then placed within a MiniCTW twin-screw extruder (ThermoScientific) at a temperature of 200 °C and a screw speed of 30 rpm, the diameter (1.75 mm) of the filament was controlled with a specific die with a set diameter.

[0092] A range of graphene-loaded PLA filaments containing 1 , 5, 15, 20 and 40 wt. %. graphene nanoplatelets were prepared by this method.

[0093] Upon consideration of the topography (TEM and SEM; Figure 1 and Figure 2 respectively) of the graphene powders used to create the graphene/PLA filament it is clearly illustrated, that the graphene is dispersed creating a conductive network throughout the graphene/PLA filament which provides the polymer with increased conductivity and electrochemical activity.

[0094] Thermogravimetric analysis (TGA) of the filaments is shown in Figure 3.

[0095] The graphene/PLA filament containing 20 wt. % graphene was 3D printed producing a test anode with a diameter of 3 mm and a thickness of 1 mm.

[0096] Raman analysis was performed on the 3D printed graphene anode (3DA) (Figure 4) where characteristic graphitic D, G and 2D peaks are present at approximately 1300, 1600 and 2700 cm^’1 respectively. The Raman spectra indicates that the AM/3D printing of the graphene/PLA results in agglomeration of the graphene sheets, which is as expected and has been postulated within previously reported literature (Wei, Li et al., 2015; Foster, Down et al., 2017). This is further confirmed with full width half maximum (FWHM) analysis of the 2D peak exhibiting a value of 74 cm ¹, which is significantly larger than that of the corresponding values of FWHM analysis for monolayer or quasi- layer graphene, 28 cm^’1 (Kim, Coh et al., 2012) and 58 cm^’1 (Lin, Ye et al., 2015) respectively, indicating that the 3DA comprises multi-layer graphene.

[0097] Next, XPS analysis was undertaken with high-resolution scans made over the C 1 s and O 1 s photoelectron peaks. These were found to be broad and of an unusual peak shape. It was observed that sub-sets of the components present appeared to shift by different amounts under different conditions of charge neutralisation. This indicated that the samples contained materials of differing electrical conductivity and therefore exhibited this differential charging effect. The components presented in Figure 5 were identified as the carbon phase (graphene) with some PLA bound to it exhibiting the same conductivity and an isolated PLA phase not bound to the carbon phase, thus acting essentially as an insulator.

[0098] A sharp and intense peak in the range 284.5 eV - 285.0 eV was observed to represent C-C bonds and a weak broad peak in the range 290.5 - 292.0 eV (Gao, Liu et al., 2016) at between 5 and 8% of the first peak above was observed to represent graphitic plasmon losses. A group of three peaks separated by 1.6 eV and of the same line shape and intensity to represent the C-C, C-0 and C(=0)0 components of PLA. When the charge neutralisation conditions of the measurement were varied, this group maintained a fixed relationship to the main C-C peak above and, therefore, represents PLA intimately bound to the graphene component.

[0099] Nonetheless, the PLA was present in two forms. The conducting and insulating PLA phases were at approximately the same levels in the graphene/PLA samples, as judged from the relative intensities of their components in the C 1 s peak. The O 1s peaks show the same differential charging phenomena as the C 1s peaks (Figure 5). The O 1s could be modelled using two sets of coupled components of equal intensity representing C-O and C=0 in PLA, along with a low intensity further component representing oxygen bound directly to the graphene. The presence of such oxygen, although at low levels, would add to the complexity of the C 1s peak envelope and may account for the imperfect fits obtained with the model used. [00100] In summary, XPS analysis reveals that the high volume of graphene within the graphene/PLA filament is fully dispersed within the PLA creating a conductive pathway throughout the sample.

Energy capabilities of the additive manufactured/3D printed graphene/PLA anodes

[00101] The energy capabilities of the 3DAs were next evaluated within a Li-ion battery setup. As a model to benchmark and understand their performance, the anodes were AM/3D printed with the same geometries as a CR2016 coin cell (i.e. a diameter of 17.75 mm with a thickness of 1 mm) using a conventional fused deposition modelling 3D printer.

[00102] CR2016-type coin cells were assembled inside a mBraun glovebox (H₂CXO.5 ppm, C>₂<0.5 ppm) using the metallic lithium counter/reference electrode, a polypropylene separator (Celgard 2400), an electrolyte of 1 M LiPF₆ in ethylene carbonate and dimethyl carbonate (EC-DMC, 1 :1 ) and a 3DA of a diameter of 17.75 mm and a thickness of 1 mm prepared using 20 wt.% graphene/PLA filament as described above. The freestanding anodes do not require a copper current collector.

[00103] Charge-discharge measurements were carried out galvanostatically over a voltage range of 0.01-3.00 V using the Arbin battery test system (BT2000).

[00104] It is important to note, as exhibited within Figure 6, that these graphene 3DAs as it did not provide a highly beneficial electrochemical response. Providing an initial capacity of approximately 20 mAh g ¹, at a current density of 40 mA g ¹, with a substantial capacity loss over the remaining subsequent 200 scans.

[00105] To understand such low electrochemical behaviour, we next analysed the topography of the graphene 3DA. Figure 6 presents SEM images where it is evident that the surface of the 3DA provides sufficient percolation, however does not offer an effective porosity for electrolyte wetting. In order to overcome this limitation, we next induced porosity within the 3DAs, by introducing a chemical treatment of the anode using NaOH.

[00106] After a 24 hour pre-treatment in aqueous NaOH, the anode material offers a significantly improved porosity. It is important to understand that this material did not lose its 3D PLA structure, as shown with TGA analysis in Figure 7, where the percentage of graphene remains at 20 wt. %, and maintains integrity, but now offering an excellent electrochemical behaviour/performance. [00107] This porous AM/3D printed graphene/PLA anode exhibits an initial charge of approximately 1100 mAh g^~1 (at a current density of 40 mA g^~1). After formation of the solid electrode interface (SEI) between scans 2-20, a capacity of 590 to 300 mAh g ¹ was realised, increasing back to 500 mAh g ¹ between scans 60-80. After 80 scans, a stabilisation of the anode was demonstrated, with a specific capacity ranging between approximately 200 and 100 mAh g ¹.

[00108] When comparing these specific capacities to that of the theoretical capacities for graphene and graphite (744 and 375 mAh g^~1 respectively), (Wang, Shen et al., 2009) it is clear that after the stabilisation of the anode that the specific capacities are larger than graphite but lower than graphene. Therefore, we suggest that the graphene incorporated within the 3DA, is predominantly graphene-like in its electrochemical behaviour, and that the increased surface area of the graphene nanoplatelets within the composite provide the improved energy outputs.

[00109] The results presented herein enhances the field of additive manufacturing/3D printed energy storage devices with the utilisation of a tailorable graphene/PLA filament, and with a simple chemical treatment of the 3D printed anode can exhibit a 200-fold increase within the specific capacity (after anode stabilisation).

Example 2 - Sodium-ion battery formed entirely of AM/3d printed components Materials and Methods

[00110] All chemicals used were of an analytical grade and used without any further purification from Sigma-Aldrich unless stated otherwise. The solutions were prepared with deionised water of resistivity not less than 18 MW cm. Electrochemical measurements were carried out at room temperature using an Autolab PGSTAT302N (UK).

[00111] Powder X-Ray Diffraction (XRD) was performed on an X'pert powder PANalytical” model with a copper source of Ka radiation (of 1.54 A) and Kb radiation (of 1.39 A), using a thin sheet of nickel with an absorption edge of 1.49 A to absorb Kb radiation. A reflection transmission spinner stage (15 rpm) was implemented to hold the commercially sourced NaMnC>2 powder. The range was set between 10° and 120° 2Q in correspondence with literature ranges.

[00112] Solid-state NMR experiments were performed under 60 kHz MAS, using a 1.3mm double resonance HX probe. 23Na 1 D spin echo spectra were recorded at room temperature on a Bruker 400 MHz Avance III spectrometer (Germany) equipped with a triple resonance probe with the x-coil on the outside (TXO) flow probe that was linked directly to an automated SABRE polarization system.

[00113] All 3D printing composite filaments were prepared using a Thermo Haake Rheomix 600 mixing bowl fitted to a Thermo Haake Polydrive dynamometer unit. The bowl was fitted with Banbury rotors. All polymer-based composites were performed at 180°C and at 70rpm, utilising a commercially available ABS [Axion ABS52 1003, Axion Group, UK],

[00114] The 3D printed designs were drawn using 3DS’s Solidworks, and were printed utilising either a Filament Deposition Modelling (FDM) 3D printer (ZMorph, Warsaw, Poland), using a custom drilled 1.0 mm diameter nozzle to prevent blockages, or a stereolithography (SLA) printer (Form2, Formlabs, USA).

Ink Based Na-lon Battery

[00115] In order to manufacture a working energy storage architecture by 3D printing two manufacturing techniques are considered. Firstly, as a proof of concept, the integration of the active materials into a screen printable formation. The NaMnC>2 was mixed with Super P carbon black, in order to provide improved conductivity and combined with a screen-printing ink binder from Gwent. A cell was 3D printed by a commercially available SLA 3D printer.

[00116] First, the proof-of-concept ink based battery was constructed, consisting of a NaMnC (64%), Super P carbon black (16%) and binder (20%) cathode, a TiC>2 nanopowder (64%), Super P carbon black (16%) and binder (20%) anode, consisting of 10 cm² electrodes mounted inside the 3D printed chassis and separator soaked in an electrolyte. Both electrodes were doctor bladed onto a 9 pm copper film [99.99% purity, MTI Corporation, USA], with a thickness of 10 pm. In order to ensure that any faults in the 3D printed cell did not cause any risk or dangerous properties during testing a highly stable and safe ionic liquid was utilised as an electrolyte. 1-ethyl-3-methylimidazolium-bis-tetrafluoroborate (EMIBF₄) with an additive of sodium salt, namely sodium tetrafluoroborate, NaBF has been show to demonstrate relative good performance, with high levels of environmental and thermal stability (Wu et al.( 2016); Down and Banks (2018). As such, an electrolyte of 0.5M NaBF₄ in EMIBF₄ was utilised, with a cellulose separator. The chassis and lid were designed to fit tightly with a locking seal, to press the electrodes tightly together without leaking any electrolyte from the cell. Kapton tape was applied around the seals to ensure no leaking or loss of electrolyte. Preparation and structural and physical characterisation of NaMn0₂

[00117] The NaMnC>2 was prepared by a solid-state synthesis adapted from Billaud et al. (2014) The solid-state route involved mixing stoichiometric amounts of Na2CC>3 and Mh2q3; with a 15% excess of the sodium to account for Na₂0 evaporation upon firing. The mixing was carried out in a ball-mill using 10mm diameter AIO₃ balls, with a ball-to-sample weight ratio of 30:1 , at a milling speed of 450 rpm. The powder was then heat-treated at 950°C for 10 hours with ramp speeds of 5.0 ⁰C/min. The resulting material was stored under vacuum until used.

[00118] In order to qualify the material produced is comparable to the NaMnCb utilised in literature, ²³Na NMR is used to properly confirm the compositions and conformity of the sample compared to those in the literature. Figure 8 shows the NMR response of the sample, exhibiting stacking akin to that of nominally pure p-NaMnC^ samples (Billaud et al. (2014). The ²³Na NMR of the NaMnC>2 sample at both 4.7 and 8.4 T show two isotropic resonances, indicating two distinct sodium environments. The isotropic resonance is primarily due to the 1/2 <® -1/2 transition, which is only affected to second-order by quadropolar interactions. The spinning sidebands present, which are highlighted by the green bars, are primarily due to the ±3/2 < ±1/2, which is only affected to second-order by the quadropolar interaction. The peaks located at roughly 438 and 240 agree closely with the theory and the characteristics observed in literature.

[00119] To understand the structural characteristics of the NaMn0₂ that allow for the sodium deintercalation and reinsertion. The structure of the NaMnC was analysed by powder X-ray diffraction, and solid-state NMR. The XRD pattern of the as-prepared monoclinic NaMnC>2 is shown in Figure 9. By utilising a Reitveld refinement of the crystalline structure the lattice parameters are defined as, a=5.649 A, b = 2.829 A, c= 5.769 A, b= 112.8°. These values are closely related to those found in literature (a= 5.63 A, b = 2.86 A, c= 5.77 A, b= 112.9°).(Fuchs, 1994). Given this and the crystalline structure of NaMnC>2, the Mn-O bond lengths in the Mn(¾ octahedron are 2.30 A (2*) and 1.84 A (4*) respectively.

Preparation of 3D printed porous electrodes

[00120] A porous polymer matrix was developed by integrating an immiscible, water soluble polymer into a 3D printable polymer matrix. A higher molecular weight PVA [M_w= 89,000 - 98,000, Sigma] is mixed into a ABS polymer matrix [1 :1 ratio], before the electrochemically active materials, NaMnC>2 for the cathode and a TiC>2 nanopowder for the anode, and the Super P carbon black as conductive filler (20 wt. %). The resulting composite is granulated and extruded into a 3D printable filament of nominal thickness 1.85 mm, using a Thermo Fisher TSE 24 MC Twin-screw Extruder and sonicated for 4 hours in water. The sonicating acts to remove micro pockets of PVA, introducing pores into the material. The resulting material is dried at 60 °C and stored under vacuum.

[00121] The filament is then printed into an electrode design of 3 mm diameter (see Figure 10). The resulting structure is a microporous electrode with significantly increased surface area, shown inset in Figure 1 1.

[00122] A corresponding non-porous PVA/ABS composite comprising 20 wt. % of Super P carbon black was prepared, as well as an 80% ABS and 20% Super P carbon black electrode both as a controls.

Energy capabilities of the additive manufactured/3D printed electrodes

[00123] 3D printed electrodes described above are characterised using the near ideal redox probe hexaammineruthenium (III) chloride. The utilisation of this probe was chosen due to its outer-sphere redox mechanism that is insensitive to the C/O ratio groups and is affected only by the electronic structure of the 3D printed electrode (i.e. sights of electrochemical activity, edge plane like-sites and defects). This is a commonly used redox probe in academic literature

[00124] Figure 1 1 shows the respective ruthenium probes of the 3 sample electrodes with a scanning rate of 100 mV/s. It can be seen that the addition of PVA into the polymer matrix (black) initially worsens the performance of the electrode when compared to the 80% ABS and 20% Super P control (green), with peak to peak separation of 78 mV and 68 mV respectively. Once the 80% ABS/PVA [1 :1] and 20% Super P has been sonicated and the micropores exposed (red) the peaks become significantly more identifiable with a peak separation of only 47 mV.

[00125] Interestingly, once the micropores have been introduced into the structure, the voltammetric responses exhibit sigmoidal behaviour, especially at lower scan rates, however without the sonication of the 3D printed electrodes demonstrate a quasi-reversible response. It is apparent that the 3D printer electrode demonstrate a large increase in current handling capabilities and significantly improved electrochemical response with micropores integrated into the structure.

Fully AM/3D Printed Na-Ion Battery [00126] Given the improved performance of the microporous electrodes the system used for the development of the electrodes in the 3D printed cell utilised this same principle. The 3D printed cells were assembled according to Figure 10, with a NaMn0₂ integrated cathode and a TiC>2 integrated anodes, both of which were manufactured with ABS/PVA [1 :1] to improve the electrochemical activity. Notably, in the case of the fully 3D printed structure, the cell’s design allows for the electrolyte to be inserted without the need of any separator. In this case the electrolyte is contained within the cell structure and the electrodes are held apart mechanically by the cell’s design. It is important to highlight that this approach means that the electrodes no longer require any current carriers, significantly reducing the manufacturing costs of the device as well as removing and required consideration to the interfacial, thin film, or constriction resistances that can negatively affect the performance of the battery.

[00127] The cells were cycled, charged and discharged under symmetric conditions, galvanostatically between 0.6 and 1.8 V. Figure 12 depicts the charge characteristics of the ink-based system and Figure 13A depicts the charge characteristics of the fully 3D printed polymer based system. In both cases, the batteries demonstrate impressive charging characteristics, with gradual transitions. A significant potential increase in the low capacities for each cycles is observed, transitioning quickly from 0.6 V to approximately 1.4 V in the initial charge for both the ink-based and polymer-based systems.

[00128] Further to this, there is notable and obvious inconsistencies and fluctuations in the gradient through the charging and discharging. There are a couple of potential causes for such fluctuation; firstly the relatively higher resistance of the electrodes, which consist of high polymer quantities can introduce instabilities in the charging characteristics, varying the internal resistance of the device, also, the electrical conductivity of the ionic electrolyte and the ionic behaviour of the salt vary greatly with temperature and potential. The conductivities of ionic liquids electrolytes have been shown to greatly increase with increasing temperature, mainly because high temperatures can promote the dissolution of sodium salt NaBF₄, the creation of free ions and the increase in the migration rate of the effective carriers. However, with the addition of the NaBF the conductivity of the electrolyte is lower than that of pure EMIBF4, due to the increase in the electrolyte viscosity, which hinders the migration of Na⁺ (Buzzeo et al., 2004; Kim et al. (2011 ).

[00129] In both cases there is a close to typical response to the increase of the applied current. The increase of charging/discharging current is shown to significantly influence the performance, as typical with batteries under these test conditions. Although this is not ground- breaking performance, the mere fact that a device mostly constructed from thermoplastics, printed from a commercially available 3D printer, and demonstrates not only energy storage, but also the typical characteristics of batteries developed under clean room conditions is remarkable. The results here show the significant potential of 3D printing in the design and prototyping of energy storage concept in the 3^rd dimension.

[00130] For the first time, sodium-ion (full cell) batteries formed entirely of components that have been fabricated via AM/3D printing, integrating active materials NaMnCh and T1O2 within a porous supporting material, before being printed into a proof-of-concept model based upon the basic geometry of a commercially available AA battery. The AM/3D printed devices demonstrates a respectable performance of 84.3 mAh g^~1, and is directly compared with a device that has been fabricated via a more typical manufacturing method utilising a ink- based/doctor-bladed methodology, exhibiting a specific capacity of 98.9 mAh m ² (1 16.35 mAh g ¹) (see Figure 13B). Despite the fact that these structures are typically made of 80% thermoplastic, they work as a fully functioning energy storage platform.

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[00131] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference in their entirety and to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein (to the maximum extent permitted by law).

[00132] All headings and sub-headings are used herein for convenience only and should not be construed as limiting the invention in any way.

[00133] The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise paragraphed. No language in the specification should be construed as indicating any non-paragraphed element as essential to the practice of the invention.

[00134] The citation and incorporation of patent documents herein is done for convenience only and does not reflect any view of the validity, patentability, and/or enforceability of such patent documents.

[00135] This invention includes all modifications and equivalents of the subject matter recited in the paragraphs appended hereto as permitted by applicable law.

Claims

1. A composition comprising at least one thermoplastic or thermosetting polymer; at least one electrically conductive filler, and optionally at least one electrochemically active material;

wherein the at least one electrically conductive filler is dispersed within the at least one thermoplastic or thermosetting polymer; and

wherein the at least one thermoplastic or thermosetting polymer comprises a plurality of pores.

2. A composition according to claim 1 wherein the at least one electrically conductive filler is selected from a carbon or metal species, or a combination thereof.

3. A composition according to claim 1 wherein the at least one electrically conductive filler is selected from graphene, graphite and carbon black, or a combination thereof.

4. A composition according to any one of the preceding claims wherein the content of the electrically conductive filler in the composition is between 1 to 40 wt.%, suitably about 10 wt.% to about 40%, more suitably about 15 wt.% to about 20 wt.%

5. A composition according to any one of the preceding claims which comprises at least one electrochemically active material.

6. A composition according to claim 5 wherein the electrochemically active material is dispersed within the at least one thermoplastic or thermosetting polymer.

7. A composition according to any one of the preceding claims wherein the electrochemically active material is selected from the group consisting of Li and oxides thereof, Na and oxides thereof, Si and oxides thereof, Se and oxides thereof, Sn and oxides thereof, Ge and oxides thereof, Sb and oxides thereof, Ti and oxides thereof, Zn and oxides thereof, Sn and oxides thereof, Co and oxides thereof, Fe and oxides thereof, Mn and oxides thereof, Ni and oxides thereof, Mo and oxides thereof, Cu and oxides thereof, a bimetallic compound or oxides thereof, a multi-metallic compound or oxides thereof, a sulfide material, a carbon material, or combinations thereof.

8. A composition according to any one of the preceding claims wherein the content of the electrochemically active material(s) in the composition is between 1 to 40 wt.%, suitably about 10 wt.% to about 30%, more suitably about 15 wt.% to about 25 wt.%

9. A composition according to any one of the preceding claims wherein the conductivity of the composition is about 100 S/m or greater.

10. A composition according to any one of the preceding claims wherein the polymer is selected from the group consisting of ABS (acrylonitrile butadiene styrene), Nylon (or polyamide), Acetate (or cellulose), PLA (poly lactic acid), terephthalate (such as PET polyethylene terephthalate), Acrylic (polymethylacrylate, Perspex, polymethylmethacrylate, PMMA), Polypropylene (or polypropene), Polystyrene (PS), PE (such as expanded- high impact-Polythene (or polyethene), Low density (LDPE) High density (HDPE)), PVC (polyvinyl chloride), Polychloroethene, and poly vinyl acetate (PVA), or a combination thereof.

11. A composition according to any preceding claim wherein the polymer is selected from PLA, ABS, HDPE and PVA, or a combination thereof.

12. A composition according to any one of the preceding claims wherein the composition has a plurality of micropores and/or nanopores.

13. A composition according to any one of the preceding claims in the form of a film, pellets, fibrous material, moulded article or filament.

14. A 3D printable filament comprising a composition according to any one of claims 1 to

12.

15. A 3D printed article comprising a composition according to any one of claims 1 to 12.

16. A 3D printed article according to claim 15 wherein the article is an electrode.

17. An electrochemical cell comprising a composition according to any one of claims 1 to

12, or a 3D printed article according to any one of claims 15 and 16.

18. A composition comprising at least two polymers selected from a thermoplastic and/or a thermosetting polymer; at least one conductive filler, and optionally at least one electrochemically active material;

wherein the at least polymers are immiscible with each other; and one of the at least two polymers is selectively soluble in a given solvent over the other; and

wherein the at least one conductive filler is dispersed within the polymer of relatively lower solubility in the solvent.

19. A composition according to claim 18 wherein the given solvent is water.

20. A composition according to claim 18 wherein at least two polymers are PVA and ABS.

21. A process for preparing a composition according to any one of claims 1 to 12 comprising:

(i) providing a first composition comprising at least one thermoplastic or thermosetting polymer; at least one conductive filler, and optionally at least one electrochemically active material;

wherein the conductive filler is dispersed within the at least one thermoplastic or thermosetting polymer; and

(ii) treating said first composition in a solvent to provide a second composition comprising a plurality of pores.

22. A process according to claim 21 wherein the at least one thermoplastic or thermosetting polymer is PLA and the solvent is aqueous NaOH.

23. A process for preparing a composition according to any one of claims 1 to 12 comprising

(i) providing a first composition as defined in any one of claims 18 to 20 and

(ii) treating the first composition with a given solvent to provide a second polymeric composition comprising a plurality of pores.