GB2577577A - Polymer battery - Google Patents

Abstract

A battery device has an anode 101 having an n-type polymer, a cathode 105 having a p-type polymer, and a separator 103 comprising a polymer mesh with a crosslinked ion-conducting polymer gel in the pores. The n-type polymer comprises a repeat unit of formula (I) and the p-type polymer comprises a repeat unit of formula (II): wherein R1 and R2 are H or a substituent; Ar1 and Ar2 are optionally substituted C6-20 arylene or heteroarylene; and Ar3, Ar4 and Ar5 are optionally substituted C6-20 arylene or heteroarylene, with at least one aromatic ring atom of Ar3 being bound directly to an adjacent repeat unit or end group of the polymer, and at least one aromatic ring atom of Ar4 being bound directly to an adjacent repeat unit or end group of the polymer. Preferably, Ar1 is phenylene and Ar2 is napthylene. Preferably, Ar3, Ar4 and Ar5 are each optionally substituted phenyl, and Ar5 may also be bound directly to an adjacent repeat unit. An electrolyte is also provided between the anode and the cathode, and is preferably an ionic liquid such as BMP-TFSI. The ion-conducting polymer in the gel separator is preferably polyethylene oxide.

Description

Intellectual Property Office Application No. GII1904393.4 RTM Date:24 September 2019 The following terms are registered trade marks and should be read as such wherever they occur in this document: Sigma-Aldrich Merck Millipore Imerys Kapton TECBOND Intellectual Property Office is an operating name of the Patent Office www.gov.uk /ipo

POLYMER BATTERY

BACKGROUND

Embodiments of the present disclosure relate to a battery device comprising an n-type and a p-type polymer.

A battery device has a cathode, a separator, and an anode between an anode current collector and a cathode current collector, and optionally a means for sealing the cathode, anode and separator to provide a barrier against ingress of water vapour, air and other materials that may negatively affect the performance of the battery device.

A conducting polymer may be provided as an active material in the anode or cathode of a polymer-based battery cell, for example as described in: JOURNAL OF POWER SOURCES, Volume 177. Issue 1, Pages 199-204 (15 February 2008); CHEM. REV., 116, 9438-9484 (2016); and CHEMICAL REVIEWS, Vol. 97, No. 1 209 (1997).

A polymer battery device having an increased charge capacity, and generally improved electrochemical performance, as exhibited by, for example, increased midpoint voltage and cycling lifetime, is desirable.

Aromatic Azomethine Polymers and Fibers, Paul W. Morgan, Stephanie L. Kwolek, and Terry C. Pletcher, Macromolecules, 1987, 20 (4), pp 729-739 describes the synthesis and detailed characterisation of conjugated aromatic polyimines with various backbone and side-group substitution structures.

Batteries containing Schiff base polymers are disclosed in W02009003224 and W02012145796.

CN 103022557 discloses a gel polymer electrolyte based on non-woven fabrics for a lithium ion battery.

U.S. patent publication no. 20150044574 discloses an electrolyte membrane including a 5 polymer layer and platelet particles, where the polymer layer is reinforced with a fiber mat and the polymer layer retains an electrolyte.

U.S. patent no. 5,665,265 discloses a polymer gel electrolyte support structure.

SUMMARY

A summary of aspects of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects and/or a combination of aspects that may not be set forth.

The present inventors have surprisingly found that a polymer battery having a polymer comprising the repeat unit of Formula I, a polymer comprising a arylamine repeat unit, and a gel electrolyte separator, exhibits synergistic improvements in charge capacity, midpoint voltage, maximum charge capacity, maximum midpoint voltage, and voltage lifetime.

The improved electrochemical performance of the polymer batteries disclosed herein provides a number of benefits including, without limitation, a higher charge capacity, a reduction in battery size for a given charge capacity, a reduction in the volume of ionic /5 liquid electrolyte required and good adhesion between the gel electrolyte separator and electrodes. The present batteries can be made by a simple lamination process, which may also reduce costs, complexity and device thickness.

In some embodiments, there is provided a battery device that exhibits increased charge capacity, midpoint voltage, maximum charge capacity, maximum midpoint voltage, and voltage lifetime.

In some embodiments, there is provided a battery device that comprises an anode comprising an n-type polymer; a cathode comprising a p-type polymer; a separator comprising a polymer mesh having mesh pores and a gel in the mesh pores wherein the gel comprises a crosslinked ion-conducting polymer; and an electrolyte between the anode and the cathode. The n-type polymer of these embodiments comprises a repeat unit of formula (I) and p-type polymer comprises a repeat unit of formula (11): ArsAr4 NN V Ar5 R2 Art-6 -N Ar2-N (I) in which R1 and R2 are each independently selected from H or a substituent; Arl and Are are each independently an unsubstituted or substituted C6-2o arylene or heteroarylene group; Ai', Ar1 and Ar' are each independently an unsubstituted or substituted C6-20 arylene or heteroarylene group; at least one aromatic ring atom of Are is bound directly to an adjacent repeat unit or end group of the polymer; and at least one aromatic ring atom of Art is bound directly to an adjacent repeat unit or end group of the polymer.

In some embodiments, R1 and R2 are H. In some embodiments, Ar1 is phenylene which is unsubstituted or substituted with one or more substituents selected from C1-20-alkyl, optionally substituted C6-1s-aryl, C1-20-alkyl ether, C km-carboxyl, C -2o-carb onyl, C -2o-ester, and optionally substituted Cs-I s-heteroaryl.

In some embodiments Are is naphthylene. Preferably, Are is a group of formula (III): in which R6 in each occurrence is independently a substituent selected from Ci-20-alkyl, optionally substituted C6-18-aryl, C1-2o-alkyl ether, C1-2o-carboxyl, C1-2o-carbonyl, C1-2o-ester, and optionally substituted Cs-is-heteroaryl and t in each occurrence is independently 0, t, 2 or 3. Preferably, each t is O. In some embodiments, Ai', Art and Ar5 are each phenyl which is independently unsubstituted or substituted with one or more substituents.

In other embodiments, Ai', AO and Ar' are each independently unsubstituted or substituted with one or more substituents selected from the group consisting of C1-2o-alkyl, optionally substituted C6-1s-atyl, C1-2o-alkyl ether, C1-2o-carboxyl, C1-2o-carbonyl, C1-2oester, and optionally substituted Cs-is-heteroaryl.

In some embodiments, an aromatic ring atom of Ar5 is bound directly to an adjacent repeat lo unit.

In yet other embodiments, the repeat unit of formula (II) has formula (Ha) (h a) wherein n, p and q are each independently 0, 1, 2, 3 or 4; and le, R4 and R5 are each independently selected from C1-2o-alkyl, optionally substituted Cs-is-aryl, C1-2o-alkyl ether, C1-2o-carboxyl, C1-2o-carbonyl, C1-2o-ester, and optionally substituted C5-18-heteroaryl.

BRIEF DESCRIPTION OF DRAWINGS

The present disclosure is described in conjunction with the appended figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.

In the appended figures, similar components and/or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar (R5)q components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.

Figure 1 illustrates a battery device according to some embodiments of the present

disclosure;

Figure 2 is a graph of charge capacity vs. cycle number for a battery device, according to Comparative Examples 2 (broken lines) and 3 (solid lines); Figure 3 is a graph of midpoint voltage vs. cycle number for a battery device, according to Comparative Examples 2 (broken lines) and 3 (solid lines); ro Figure 4 is a graph of charge capacity vs. cycle number for a battery device, according to Example 1 (solid lines) and Comparative Example 1 (broken line); and Figure 5 is a graph of midpoint voltage vs cycle number for a battery device, according to Example 1 (solid lines) and Comparative Example 1 (broken line).

DETAILED DESCRIPTION

ig The ensuing description above provides preferred exemplary embodiment(s) only, and is not intended to limit the scope, applicability or configuration of the invention. Rather, the ensuing description of the preferred exemplary embodiment(s) will provide those skilled in the art with an enabling description for implementing a preferred exemplary embodiment of the invention, it being understood that various changes may be made in the function and arrangement of elements, including combinations of features from different embodiments, without departing from the scope of the invention.

Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise," "comprising," and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to." As used herein, the terms "connected," "coupled," or any variant thereof means any connection or coupling, either direct or indirect, between two or more elements; the coupling or connection between the elements can be physical, logical, electromagnetic, or a combination thereof Additionally, the words "herein," "above," "below," and words of similar import, when used in this application, refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the Detailed Description using the singular or plural number may also include the plural or singular number respectively. The word "or," in reference to a list of two or more items, covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list.

Figure 1, which is not drawn to any scale, schematically illustrates a battery device according to some embodiments. The battery device comprises at least one anode current collector 107, one cathode current collector 109, a battery cell 100 and an adhesive composition 111. The battery cell 100 comprises an anode 101, a cathode 105, and a separator 103 between the anode and the cathode.

Polymers A battery device as described herein may comprise an n-type polymer comprising repeat units of formula (1) and a p-type polymer comprising repeat units of formula (II): W R2 Ci-Ar1-62= N11-Ar2-N2 (I) wherein R1 and R2 are each independently selected from H or a substituent; and AO and 20 Are are each independently a Co-20 aromatic or heteroaromatic group, preferably a C6-20 arylene, optionally phenylene or napthylene.

Preferably, R' and R2 are each independently selected from H, C1-2o-alkyl, optionally substituted Cs-is-aryl, C km-alkyl ether, CI-20-carboxyl, CI-20-carbonyl, C 1-2o-ester, and optionally substituted C5-18-heteroaryl. In a preferred embodiment, 121 and R2 are each H. Preferably, Arl is phenylene, more preferably meta-or para-linked phenylene which may be unsubstituted or substituted with one or more substituents selected from C1-20-alkyl, optionally substituted C6-is-aryl, CI-DJ-alkyl ether, CI-20-carboxyl, CI-20-carbonyl, C I -20-ester, and optionally substituted C5-18-heteroaryl.

Preferably, A is naphthylene, more preferably a group of formula (III): wherein R6 in each occurrence is independently a substituent selected from Ci-20-alkyl, optionally substituted C6-18-aryl, C1-2o-alkyl ether, C1-2o-carboxyl, C1-2o-carbonyl, Cr-2oester, and optionally substituted C5-18-heteroaryl and t in each occurrence is independently 0, 1, 2 or 3 io Where present, substituents of a Co-is-aryl, or a C5-18-heteroand group as described anywhere herein are optionally selected from C1-2o alkyl in which one or more nonadjacent, non-terminal C atoms may be replaced with 0, C=0 or COO.

Preferably, each t is 0.

The n-type polymer preferably has a LUMO level measured by square wave voltammetry /5 of between -4.5 and -1.5 eV, more preferably between -3.5 and -2.0 eV In some embodiments, p-type polymer s a polymer comprising a repeat unit of formula (II): Ar3N 7Ar4 Ar5 (II) wherein AO, Ar4 and Ar5 are each independently an unsubstituted or substituted C6-2o arylene or heteroarylene group; at least one aromatic ring atom of Are is bound directly to an adjacent repeat unit or end group of the polymer; and at least one aromatic ring atom of Ar4 is bound directly to an adjacent repeat unit or end group of the polymer.

Optionally, at least one aromatic ring atom of Ar5 is bound directly to an adjacent repeat unit or end group of the polymer.

The repeat unit of formula (II) may be bound to adjacent repeat units or end groups through 2, 3 or 4 bonds on AO, Ar4 or Ars.

Preferably, the repeat unit of formula (II) has formula (1Ia): wherein n, p and q are each independently 0, 1, 2, 3 or 4 and wherein R3, le and le are each independently selected from C1-20-alkyl, optionally substituted C6-18-aryl, C1-20-alkyl ether, C1-20-carboxyl, C1-20-carbonyl, C1-20-ester, and optionally substituted C 5-18-15 heteroaryl.

Preferably, n is 0. Preferably, p is O. Preferably, q is O. The p-type polymer preferably has a HOMO level measured by square wave voltammetry of between -4.5 and -6.5 eV, more preferably between -4.8 and -6 eV.

Polymers containing aromatic or heteroaromatic repeat units in the polymer backbone as described herein may be formed by methods including, without limitation, polymerisation (R5)q of monomers comprising leaving groups (groups other than H) that leave upon polymerisation of the monomers; oxidative polymerisation; and direct (hetero)arylation. Exemplary leaving groups include, without limitation: halogens, preferably bromine or iodine; sulfonic esters, for example tosylate or mesylate; and boronic acids and esters.

Exemplary polymerisation methods include, without limitation, Yamamoto polymerization as described in, for example, T. Yamamoto, "Electrically Conducting And Thermally Stable pi-Conjugated Poly(arylene)s Prepared by Organometallic Processes", Progress in Polymer Science 1993, 17, 1153-1205, the contents of which are incorporated herein by reference; Suzuki polymerization as described in, for example, WO 00/53656, io WO 2003/035796, and US 5777070, the contents of which are incorporated herein by reference; and direct (hetero)arylation as disclosed in, for example, Direct (Hetero)arylation Polymerization: Simplicity for Conjugated Polymers Synthesis", Chem. Rev. 2016,116, 14225-14274, the contents of which are incorporated herein by reference.

Electrolyte The electrolyte may be a dissolved salt or an ionic liquid. The electrolyte may be a solution of a salt having an organic or metal cation, for example lithium bis(trifluoromethylsulfonyl)imide (LiTTSI) or lithium hexafluorophosphate, in an organic solvent, optionally propylene carbonate.

Ionic liquids as described herein may be ionic compounds that are liquid at below 100 °C and at 1 atm pressure. Examples include, without limitation, compounds with an ammonium-, imidazolium-, phosphonium-, pyridinium-, pyrrolidinium-or sulfonium cation. The ionic liquid may have an anion selected from: sulfonimide, optionally bis(trifluoromethane)sulfonimide (TESI) and bis(fluorosulfonypimide) (FR); borate, for example tetrafluoroborate; phosphate, for example hexafluorophosphate; and dicyanamide 25. Examples of ionic liquids having a TFSI group arel-ethyl-3-methyl imidazolium bis(trifluoromethane)sulfonimide (EMI-TF SI), triethylmethoxyethyl phosphonium bi s(tri fl uorometh an e)sul foni mi de (TEMEP-TES1), triethyl sulfoni um bis(trifluoromethane)sulfonimide (TES-TF Si) or 1-buty1-1-methylpyrrolidinium bi s(tri fluorometh an e)sul foni mi de (BA/IP-TEST), the latter being parti cul arty preferable.

Electrode additives The anode and/or cathode as formed may consist of the n-type polymer and p-type polymer respectively. Preferably at least one of the anode and cathode, and more preferably both of the anode and cathode, comprise one or more conductive carbon materials. Conductive carbon materials may be selected from, without limitation, one or more of the group consisting of carbon black, carbon fiber, graphene, graphite, and carbon nanotubes. Preferably, the BET specific surface area of the conductive carbon material is in the range of 10 m2/g to 3000 m2/g. In some embodiments, the anode and/or cathode as formed may contain an electrolyte.

ro The anode and/or cathode may comprise a binder. The binder is preferably a water soluble polymer, more preferably alginic acid and salts thereof, preferably metal salts thereof, most preferably an alkali salt such as sodium or potassium alginate.

Current collector In some embodiments, the anode current collector and cathode current collector each independently comprise or consist of a layer of conductive material, for example a metal, e.g. copper or aluminium; a metal alloy, e.g. steel; a conductive metal oxide, e.g. indium tin oxide; a conducting polymer, e.g. poly(ethylene dioxythiophene) or polyaniline; or a conductive carbon allotrope, e.g. amorphous carbon, graphene, carbon nanotubes, carbon fibre or graphite powder.

Each current collector may independently be single conductive layer which may or may not be laminated with one or more further layers. In some embodiments, the current collector may be laminated to a glass or plastic layer.

In some embodiments, the current collector may be a conductive layer which is part of a laminate further comprising at least one metal layer. In some embodiments, the laminate comprises the current collector layer, at least one polymer layer and at least one metal layer. One or more polymer layers may be provided between the current collector layer and the one or more metal layers.

In some embodiments, each current collector may be supported on a suitable substrate, for example a glass or plastic substrate. In some embodiments, the substrates may be flexible, particularly for applications in which flexibility of the battery is desirable, and / or to enable use of a roll-to-roll process in battery formation. In some embodiments, an exemplary flexible current collector is a metal foil, for example aluminium foil.

Separator The separator comprises a polymeric mesh having a mesh structure defining pores therein. At least some pores comprise an ion-conducting crosslinked polymer therein. The crosslinked polymer comprises an electrolyte absorbed therein.

The polymeric mesh is preferably nylon. The polymeric mesh is preferably woven. Preferably, the thickness of the mesh is less than 250 microns. Preferably, the woven threads have a width of less than 200 microns.

ro Preferably, the pores have an average size of less than about 200 microns, more preferably less than 100 microns or less than 50 microns. The pores preferably have an average size of at least 5 microns. Preferably, the crosslinked polymer fills substantially all of the pore area of the pores.

The crosslinked polymer is suitably a hydrophilic polymer. The crosslinked polymer /5 preferably comprises polar groups. The crosslinked polymer is preferably a C2-5 alkylene oxide polymer. Optionally, the crosslinked polymer comprises or consists of crosslinked poly(ethylene oxide) (PEO). The use of an alkylene oxide polymer such as PEO is particularly preferred in combination with a nylon polymeric mesh.

The crosslinked polymer may be a mixture of more than one polymer, optionally a mixture of two or more ion-conducting polymers of differing only in molecular weights, optionally two or more PEO polymers of differing molecular weights.

The or each ion-conducting polymer may have a weight average molecular weight (Mw), before crosslinking, in the range of 5x103 to lx 1 05, and preferably 1x104 or 1 x 10' to lx107Da The electrolyte may be a dissolved salt or an ionic liquid. The electrolyte may be a solution of a salt having an organic or metal cation, for example lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) or lithium hexafluorophosphate, in an organic solvent, optionally propylene carbonate.

-I I-

Preferably, the electrolyte is an ionic liquid. Preferably, the ionic liquid is the only ionic material of the separator.

The ionic liquid may be ionic compounds that are liquid at below 100 °C and at 1 atm pressure. Examples include, without limitation, compounds with an ammonium-, imidazolium-, phosphonium-, pyridinium-, pyrrolidinium-or sulfonium cation. The ionic liquid may have a sulfonimide anion, for example bis(trifluoromethane)sulfonimide (TFSI) ionic liquids such as e.g. 1-ethyl-3-methyl imidazolium bis(trifluoromethane)sulfonimide (EMI-TF SI), triethylmethoxyethyl phosphonium bis(trifluoromethane)sulfonimide (TEMEP-TF SI), triethyl sulfonium ro bis(trifluoromethane)sulfonimide (TES-TF SI) or 1-butyl-1-methylpyrrolidinium bis(trifluoromethane)sulfonimide (BMP-TFSI), the latter being particularly preferable.

The material in the pores may consist of the crosslinked polymer and the electrolyte, or may comprise one or more further materials. Optionally, the crosslinked polymer is mixed with a plasticiser, optionally a glyme. Tetraglyme is particularly preferred.

ig A separator as described herein may be formed by introducing an ion-conducting polymer, for example PEO, into the pores of a polymer mesh followed by crosslinking of the polymer.

The ion-conducting polymer may be introduced into the pores of the polymer mesh when in a molten state or in a solution. Preferably, the ion-conducting polymer has a melting point of less than less than 200°C, more preferably less than 150°C.

The polymer mesh may be pressed into the molten ion-conducting polymer in order to introduce the ion-conducting polymer into the pores. The ion-conducting polymer may be heated, optionally at a temperature of 80°C or more, to maintain the ion-conducting polymer in a molten state during pressing.

A solution comprising the ion-conducting polymer and electrolyte may be applied to the polymer mesh followed by evaporation of the solvent or solvents of the solution.

The ion-conducting polymer and polymer mesh may be pressed by a roller, optionally by passing the ion-conducting polymer and polymer mesh through two rollers having a gap therebetween. The gap between the rollers may be selected according to the desired thickness of the separator. The or each roller may be heated.

The ion-conducting polymer may be crosslinked following its introduction into the pores of the polymer mesh. Any suitable crosslinlcing method may be used including, without limitation, heating and / or UV irradiation of the ion-conducting polymer.

The crosslinked polymer may comprise covalent bonds between chains of the ion-conducting polymer and / or, if present, a plasticiser.

The crosslinked polymer may comprise non-covalent bonds, optionally hydrogen bonds, between chains of the ion-conducting polymer. Optionally, the crosslinlcing results in 10 formation of non-covalent bonds only between polymer chains.

The polymer chains of the ion-conducting polymer may comprise groups capable of reacting to crosslink the polymer chains.

The ion-conducting polymer may be mixed with a crosslinking agent, for example a benzophenone, optionally 4-methylbenzophenone.

The ion-conducting polymer may be the only material introduced into the pores of the polymer mesh, or it may be a mixture of two or more materials. Preferably, a mixture comprising or consisting of the ion-conducting polymer and a liquid at 25°C, preferably an ionic liquid, a solution of an electrolyte and / or a plasticiser, is introduced into the pores.

Preferably, the ion-conducting polymer and the liquid form a gel upon crosslinking of the ion-conducting polymer.

The electrolyte may be provided in the range of about 0 1 mL / g of polymer to 5 mL / g of polymer. The use of the mesh may provide the composite separator with greater mechanical stability than a separator film consisting an electrolyte absorbed in an ion-conducting polymer. This greater stability may allow a greater volume per unit weight of the polymer to be provided in the composite separator.

A protective film may be provided on one or both sides of the ion-conducting polymer and polymer mesh while they are being pressed together. The protective film may be removed before or after, preferably after, crosslinking of the ion-conducting polymer.

Optionally, the completed separator has a thickness of no more than 200 microns, optionally no more than 100 microns. Optionally, the completed separator has a thickness of at least 10 microns. The crosslinked polymer extends through at least some, preferably all, of the thickness of the polymeric mesh.

To form a battery cell, one surface of the separator is brought into contact with an anode and an opposing surface of the separator is brought into contact with a cathode.

If the ion-conducting polymer does not contain an electrolyte when it is introduced into the pores then it may be absorbed into the separator following formation of the composite of the mesh containing ion-conducting polymer in the pores thereof Preferably, the electrolyte is absorbed into the composite before the separator is brought into contact with the anode or cathode of the battery.

_15 Suitably, the anode and cathode are each in electrical contact with, more preferably directly adjacent to, a respective anode and cathode current collector.

The anode, cathode and separator may be pressed together, to improve adhesion between the separator and one or both of the anode and the cathode.

Assembly Battery formation A battery cell as described herein may be formed by applying the n-type polymer to the surface of an anode current collector to form the anode; applying the p-type polymer to the surface of a cathode current collector to form the cathode; placing a separator between the anode and cathode; and pressing the anode and cathode together.

The n-type polymer and/or p-type polymer may be deposited as a component of a composition comprising one or more additives as described above to form a composite electrode. The composition may be deposited from a formulation comprising the composition dispersed in one or more solvents by any suitable coating method including, without limitation, doctor blade coating, drop casting, dispense printing, and screen printing, followed by evaporation of the one or more solvents.

Applications A battery as described herein may be used as a power source for any device, preferably for a portable device such as a phone, tablet or laptop, or a wearable device. A battery as described herein may be provided on a card, for example a debit, credit, prepayment or business card comprising an electrical device including, without limitation, a display, a speaker, a transmitter or a receiver.

The battery cells described herein, and batteries comprising a plurality of these cells, may be flexible. Preferably, a battery cell as described herein is capable of bending to give a circular arc of at least 10°, optionally at least 20° or 40°.

Some embodiments of the present disclosure provide a thermoplastic composite material for thermal sealing of flexible battery electrodes of a flexible battery. The composite is formed by impregnation of a thermoplastic bonding agent into the pores of a mesh _15 material. The mesh material acts as a spacer to prevent shorts from electrode-electrode contact, and the thermoplastic bonding agent bonds the electrodes together when heated above the melting point of the bonding agent. The thermoplastic composite material bonds the flexible electrodes together to provide a highly conformable battery. Direct bonding of the battery's current collector provides an additional encapsulated battery formed from its constituent electrodes, without the need for an encapsulating layer and without the risk of electrical shorting between the cathode and anode current collectors. By removing the need for extra layers to encapsulate the electrodes and other material of the cell, the cell, in accordance with the present disclosure, is flexible/conformable and can be used in a wearable device, a wearable medical system and/or the like.

Example 1

Gel Separator 1.0 g of PEO (100k) available from Sigma-Aldrich, CAS number 25322-68-3, 1.0 mL of tetraethylene glycol dimethyl ether (tetraglyme) available from Sigma-Aldrich and 0.21 g of 4-Methylbenzophenone (MBP) were mixed in a pestle and mortar at 120 °C until the PEO(20k) fully melted and a viscous liquid formed. 2.0 mL of 1-butyl-h methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMP-ITS1) was added and the mixture stirred until homogenous.

The molten polymer mix was deposited in a line across the top of a 50 p.m thick sheet of PET. A hydrophilic nylon net filter with a 4L0 pm pore size available from Merck Millipore (part number NY4104700) was cut to size and placed on top of the deposited molten polymer mixture. Another sheet of PET was placed on top of the nylon mesh.

The PET-polymer-nylon-PET sandwich was pressed between two hot plates heated to 120 °C and then laminated at 100 °C to form a thin film of PEO evenly distributed in the pores of the nylon mesh.

Without removing the PET sheets, the polymer mixture was cured using UV light (250 W UVH 255 hand lamp with an iron-doped metal halide lamp, intensity >80 mW cm-2) for 6 minutes either side under an inert, dry atmosphere.

/5 The resulting gel/nylon composite separator was cut to size and then peeled off the PET substrate to give a film having a thickness of between 40-65 p.m.

Current Collectors Al/PET foil (All Foils), consisting of an 18 p.m thick aluminium foil with a 12 pm PET backing, was cold laminated to a cutting mat with the PET contacting the adhesive side of the mat. A layer of pressure sensitive adhesive, cut to the same dimensions as the Al/PET, was cold laminated to the aluminium surface. A second layer of Al/PET cut to the same dimensions as the first, was cold laminated to the pressure sensitive adhesive, with the PET contacting the adhesive. The double laminate was peeled from the mat prior to use.

n-type Polymer A 3-necked round-bottomed flask, equipped with a magnetic stirrer, Dean-stark apparatus, condenser, nitrogen inlet and exhaust was charged with naphthalene-1,5-diamine (15 g, 94.8 mmol) and toluene (75 mL) Then terephthalaldehyde (12.7 g, 94.8 mmol) was taken in toluene (75 mL) and it was added to the reaction flask. The reaction was refluxed under Dean-Stark condition for 24 h with azeotropic water removal. The orange solid formed was recovered by filtration of the warm solution and dried to get 16 g of crude material. The solid was triturated with THE (160 ml) for 4 h at 28 °C. The solid was filtered and dried in a vacuum oven at 50 °C to afford 13 g of n-type Polymer 1 as an orange solid.

CI-IN analysis: C: 82.82, H: 4.829: 10.78 (expected: C: 84.35, H: 4.72, N: 10.93). a,

ef;)-N.

n-type Polymer 1 p-type Polymer I A 2 L 3-necked round-bottomed flask, equipped with a mechanical stirrer, nitrogen inlet ro and exhaust. Triphenylamine (40 g, 0.163 mol) and Iron trichloride (79.4 g, 0.489 mmol) were charged to reaction flask and purged with nitrogen. Then degassed 1,2-dichloroethane was added (1200 mL) to the reaction mixture and it was heated to 85 °C for 48 h. Once cooled the reaction mixture was poured into the acetone (2 L) stirred for 30 mins. The solid was filtered to afford 40 g of crude material which was triturated with is THE (1200 mL) at 28 °C overnight, filtered and triturared again with methanol (1200 ml) at 70 °C for 16 hours. The solid was recovered by filtration and dried in a vacuum oven at 50 °C to afford 30 g of p-type Polymer 1. CHN analysis C: 83.69, H: 5.26, N: 5.40 ( expected C: 89.23; H: 4.99; N: 5.78).

p-type Polymer 1 n-type Formulation n-type Polymer 1 (930 mg) was blended with Super P® Conductive Carbon obtained from Imerys Graphite & Carbon (373 mg) and the dry materials were mixed using a pestle and mortar for 5 minutes. To this mixture was added 28 ml of a solution of sodium alginate (commercially available from Sigma-Aldrich) (2 wt.% in a water:2-butoxyethanol (95:5 V/V) mixture), and 133.3 µl 1-butyl -1-methyl pyrroli di ni um bi s(tri fluoromethyl sulfonyl)imi de (BMP-TF SI, 24 mg) obtained from Solvionic and the mixture was mixed until a smooth paste was obtained.

The paste composition by weight was n-type Polymer 1: Super 13' Carbon Black: BMP-io Sodium Alginate 45:18:9:27 with a total content of these electrode components of 7.3 wt% . p-type Forint/fano,' A p-type formulation was prepared in the same way as for n-type Formulation Example 1 except that p-type Polymer 1 was used in place of n-type Polymer 1 yielding a paste having a p-type Polymer 1: Super 13' Carbon Black: BMP-TFSI:Sodium Alginate weight ratio of 56:21:5.6:17 with a total cathode component content of 11.9 wt%.

Deposition Before deposition, current collectors were rinsed with IPA and dried using a nitrogen gun. Kapton tape (1.5 cm width) was used to secure the current collectors to the hotplate and define the active material area into which the electrode paste was to be dropcast. Electrode pastes were dispensed in a single step with an electronic pipette onto the current collectors. The paste was dried on the hotplate at 70 °C. The Kapton tape was then removed from the electrodes, and the electrodes were transferred to the glove box and baked on a hotplate for 150 °C for 30 minutes to remove any residual moisture. Electrode loading (in mg/cm') was determined by weighing the substrate before and after deposition of the electrode material.

For the anode, 1 9 mL of anode paste was dispensed onto the anode current collector to give a final electrode loading of 5.0 mg/cm' polymer per electrode.

For the cathode, 3 1 mL of cathode paste was dispensed onto the cathode current collector to give a final electrode loading of 4.1 mg/cm' polymer per electrode Adhesive l spacer composition Hydrophilic nylon mesh with a 41.0 pm pore size, 33 r.mi wire diameter, 50 tan thickness was sourced from PlastOk was cut to size and placed on A3-sized sheet of siliconized paper. Hot TECBOND 261 EVA 12 mm flexible glue was dispensed from a glue gun. Double-sided silicone release paper was folded over the glue covered-nylon, and the paper and nylon pressed between two hotplates heated to 135 °C for 5 minutes. The composite was then laminated at 135 °C to squeeze the excess of hot glue out from the nylon mesh.

The substrate was laid flat until the glue had cooled and solidified. The thermoplastic-nylon composite was removed from the paper substrate and the excess glue trimmed off with a scalpel. The heat-laminate-cool-trim steps were repeated a second time to ensure any excess glue was removed. The thermoplastic-nylon composite was cut to make a rectangular frame having an outer perimeter and an inner perimeter.

Assembly plate PTFE-coated release paper was cut to size and placed on top of a 20mm thick aluminium plate. A silicone rubber sheet was cut to make a frame with a frame aperture sized to fit the battery. Two plates were prepared.

Battery formation Using a syringe, BMP-TFSI was dispensed dropwise across the cathode (0.6 mL) and anode (0.4 mL) active material surface and the liquid was left to soak into the material. The cathode was placed on the first assembly plate, the cathode material facing away from the plate. The thermoplastic-nylon composite frame was then placed onto the anode such that the active material was located within the frame hole. The separator was placed over the electrode active material and thermoplastic-nylon composite frame so that the anode active material was completely covered. A second gel electrolyte separator was placed directly on top of the first. A droplet of hot glue was dispensed from a hot glue gun onto each of the four corners of the spacer and permitted to cool. The anode was placed on the stack with the anode material towards the separator and aligned with the cathode material beneath. A second assembly plate was placed on top of the anode and the assembly aligned. The assembly was baked in a vacuum oven at 135 °C for 1.5 hr under vacuum, and then left to cool. The assembly was removed from the oven and the battery released from the assembly plates.

Battery testing The battery was tested under ambient atmospheric conditions.

The battery was cycled on an Arbin Model -BT2043 battery tester with the following test method 1: 1. CCCV charging step (1 mA/cm2 to 3 V, CV step until 0.2 mA/cm2 is reached) and ro constant current discharge at 1 mA/cm2 to 1 V. Repeat until the capacity falls below QT80.

The mid-point voltage and charge capacity/cm2 were calculated for each cycle. The midpoint voltage is defined as the voltage at t/2, where t is the total discharge time of the battery for a given cycle. Charge capacity (expressed in units of mAh cm') is calculated /5 as the time required to discharge to the end voltage multiplied by the cathodic current, and divided by the active area.

Comparative Example 1 Filter Paper Separator Filter papers were cut to size and dried overnight in a vacuum at 120 °C. Before use, the filter paper was soaked in BMP-TFSI liquid electrolyte.

A battery was prepared and tested as in Example 1 except that a filter paper separator was used in place of the gel electrolyte separators.

Comparative Example 2 In Comparative Examples 2 and 3, polymers F8BT and F8TFB were used rather than n-5 type Polymer 1 and p-type Polymer 1: ca° CEIH17 F8TFB F8BT Electrode stack formation Each electrode was composed of three stacked, free-standing active material sheets.

Formulations for forming n-type or p-type freestanding electrode films were formed by 5 mixing n-type polymer F8BT or p-type polymer F8TFB respectively with Super P Conductive Carbon and ionic liquid 1-Butyl-1-methylpyrrolidinium bis(tritluoromethylsulfonyipimide (BMP-TFST) in a Polymer: Carbon: Ionic Liquid weight ratio of 1.0: 0.8: 0.2.

mg polymer and 96 mg carbon were mixed using a stirrer bar on a hotplate (70°C, to 500RPM), in a glass vial with 10 ml of o-dichlorobenzene (o-DCB), until a smooth paste was obtained. Then, using a micropipette, 17 RL, of BMP-TFSI was added and mixed with the polymer: carbon paste for 30 minutes.

Freestanding electrode films Freestanding n-type and p-type electrode layers were formed from the formulations ig described above.

In each case, 3 ml of the formulation suspension was pipetted onto a smooth substrate of Al on glass which was placed on a hotplate at 70°C. The formulation was allowed to dry to form a 40 micron thick film and was then removed from the substrate.

The films were cut to a 1 x 1.5 cm area, transferred to a glovebox and baked at 150C for 30 minutes to remove any residual moisture.

Battery assembly 3 freestanding electrode films, selected from one of n-type (F8TFB) and p-type (F8BT) freestanding electrode films, were placed on a current collector of thermally evaporated aluminium on glass, with BIVIP-TFSI being applied between the films.

A gel separator (see Example 1) was placed on top of the electrode layers.

Three of the other of n-type and p-type freestanding electrode films were placed on the separator with BMP-TFSI being applied between the films and the device was completed by placing a current collector of aluminium on glass thereon.

The layers of the device were held together with a clip. Batteries were placed in a sealed container under an inert atmosphere and connected to an Arbin battery tester (Model -BT2043).

Comparative Example 3 A battery was prepared and tested as in Comparative Example 2 except that a filter paper separator was used in place of the gel electrolyte separators.

Figures 2 and 3 compare the performance of batteries of Comparative Examples 2 and 3, which have an F8BT anode and a F8TFB cathode and in which the battery separator is either a gel electrolyte separator (Comparative Example 2), or an electrolyte-soaked filter paper (Comparative Example 3). As can be seen in Figure 2, F8BT/F8TFB batteries with a gel electrolyte separator had a significantly shorter charge capacity lifetime (QT80ave 7=- 138) compared to the comparable batteries using a filter paper separator (QT80ave 235).

As can be seen in Figure 3, higher initial midpoint voltages were obtained for the gel electrolyte separator devices (Vmax = 2.08 V) compared to F8BT/F8TFB batteries with a filter paper separator (Vmax 1.99 V). Without thereby being limited by theory, this effect may be due to the lower impedance of the gel electrolyte separator as a result of its reduced thickness compared to the filter paper separator. However, voltage lifetimes (Figure 3) showed a similar trend to that of capacity lifetimes: the F8BT/F8TFB batteries with a gel electrolyte separator had reduced voltage lifetimes compared to a F8BT/F8TFB batteries using a filter paper separator. Consequently, the midpoint voltage of the gel electrolyte batteries fell below that of the filter paper battery after -150 cycles.

Figure 4 compares the charge capacity vs. cycle number exhibited by a battery devices according Example I and a battery of Comparative Example I. Figure 5 compares the midpoint voltage vs. cycle number battery devices according to Example I and a battery device according to Comparative Example 1.

As can be seen in Figures 4 and 5, and in striking contrast to the F8BT/F8TFB batteries, batteries of Example I featuring a gel electrolyte separator exhibited significantly higher capacities and voltage lifetimes compared to the same devices using a filter paper separator. In addition, the maximum charge capacities and midpoint voltages for gel electrolyte separator batteries of Example 1 were higher than that of a filter paper ro separator battery of Comparative Example I. The combination within a battery of Example 1 of a polymer comprising the repeat unit of Formula I, a polymer comprising a arylamine repeat unit, and a gel electrolyte separator therefore provided synergistic improvements in charge capacity, midpoint voltage, the maximum charge capacity, the maximum midpoint voltage, and voltage lifetime.

ig The improved properties of the batteries of the present disclosure provide a number of benefits. Because of the improved electrochemical performance herein, a higher charge capacity may be obtained by the present batteries compared to, for example, F8BT/F8TFB batteries. Alternatively, a smaller battery may be required for a given charge capacity. A reduced volume of ionic liquid electrolyte is required by the present batteries for good electrochemical performance compared to, for example, F8BT/F8TFB batteries, thus reducing costs. The present batteries also exhibit good adhesion between the gel electrolyte separator and electrodes, thus enabling a durable flexible battery. The present batteries can be made by a simple lamination process, which may reduce costs, complexity and device thickness.

In the description above, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of implementations of the disclosed technology. It will be apparent, however, to one skilled in the art that embodiments of the disclosed technology may be practiced without some of these specific details.

The teachings of the technology provided herein can be applied to other systems, not necessarily the system described below. The elements and acts of the various examples described below can be combined to provide further implementations of the technology. Some alternative implementations of the technology may include not only additional elements to those implementations noted below, but also may include fewer elements. These and other changes can be made to the technology in light of the following detailed description. While the description describes certain examples of the technology, and describes the best mode contemplated, no matter how detailed the description appears, the technology can be practiced in many ways. Details of the system may vary considerably in its specific implementation, while still being encompassed by the technology disclosed herein. As noted above, particular terminology used when describing certain features or ro aspects of the technology should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the technology with which that terminology is associated. In general, the terms used in the following claims should not be construed to limit the technology to the specific examples disclosed in the specification, unless the Detailed Description section explicitly defines /5 such terms. Accordingly, the actual scope of the technology encompasses not only the disclosed examples, but also all equivalent ways of practicing or implementing the technology under the claims.

To reduce the number of claims, certain aspects of the technology are presented below in certain claim forms, but the applicant contemplates the various aspects of the technology in any number of claim forms. For example, while some aspect of the technology may be recited as a computer-readable medium claim, other aspects may likewise be embodied as a computer-readable medium claim, or in other forms, such as being embodied in a meansplus-function claim.