Conductive Binder Materials

Abstract

An electrode comprised of an active material and a binder material, the binder material comprising a copolyester comprising repeat units derived from a diol, a dicarboxylic acid, and a poly(alkylene oxide), the binder material may further comprise a first metal ion-containing component selected from a conductive ceramic particulate material and / or may further comprise additional metal ions from one or more sources other than the conductive ceramic particulate material.

Description

Detailed Description of the Invention

[0001] The present invention relates to binder materials, electrodes made from the binder materials, and methods for the manufacture of electrodes. In particular, the present invention relates to binder materials and electrodes that exhibit the properties required for use as electrodes in metal-ion batteries, especially lithium-ion batteries.

[0002] Lithium-ion batteries are widely used in the field of rechargeable batteries, which is expected to continue to grow for the foreseeable future, due in part to the increasing demand for consumer electronics and renewable energy storage. During the operation of the battery (i.e., during charging and discharging), lithium ions are transferred between the electrodes (i.e., between the anode and the cathode). Typically, each electrode is made of multiple components, including an electrochemically active material, an optional conductive additive (such as carbon), and a binder material. The binder material must enable the movement of lithium ions through the electrode. Furthermore, the binder material plays an important role in the mechanical stability of the electrode. The binder material is typically a fluoride resin, especially polyvinylidene fluoride (PVDF), given its favorable rheological properties and electrochemical stability. Typically, a composition or slurry of these multiple components is coated or otherwise deposited as a thin film on a current collector to form a solid electrode upon drying. Thus, the solid anode is in contact with the anode current collector, and the solid cathode is in contact with the cathode current collector.

[0003] A problem with known electrodes is that they are not easily recyclable. At the high temperatures used during metal extraction, toxic gases can result from the decomposition of the PVDF binder. However, it is difficult to separate and recover the PVDF binder, especially because there are few solvents capable of dissolving PVDF so that it can be recovered from used electrodes in an environmentally friendly manner. Typical solvents capable of dissolving PVDF itself have environmental concerns. It would therefore be desirable to provide binder materials and electrodes that are more easily recyclable than known electrodes that include a PVDF binder, for example by providing binder materials and electrodes that can be recycled while avoiding the solvents typically used to dissolve PVDF.

[0004] Commercially available lithium-ion batteries are usually provided as wet cell batteries that contain a microporous separator and a liquid or gel electrolyte. The microporous separator is placed in contact between two solid electrodes. Typically, microporous separators for lithium-ion batteries have a thickness of about 20 μm to about 25 μm and are based on stretched polyolefin films (particularly polyethylene and polypropylene). The separator allows the movement of the liquid or gel electrolyte through its pores, thereby allowing the movement of lithium ions, but prevents direct electrical contact between the anode and cathode in the battery. However, concerns remain about the safety of wet cell lithium-ion batteries, which have been known to catch fire or even explode. The pore network can lead to the growth of lithium dendrites between the anode and cathode, which can result in short circuiting, thermal runaway, and flammability of the battery.

[0005] Dry cell batteries have been developed that alleviate some of the safety concerns mentioned above. These dry cell batteries instead contain a solid separator between two solid electrodes, which prevents contact between the electrodes and provides a physical barrier to dendrite growth. In dry cell batteries, the potentially flammable liquid or gel electrolyte is eliminated. The separator must therefore effectively function as both a separator and an electrolyte, and in the case of lithium-ion batteries, the separator must allow the movement of lithium ions within its structure.

[0006] In particular, lithium ion migration must be allowed across the separator-electrode interface. Thus, high interfacial compatibility between each of the solid electrodes and the separator is desired to facilitate lithium ion migration. However, it is difficult to achieve interfacial compatibility between the solid electrodes and solid separators in dry cell batteries that is comparable to that achieved in wet cell batteries, where wetting allows the liquid electrolyte to fully penetrate into the electrodes. Thus, it would be desirable to improve the interfacial compatibility between the solid electrodes and solid separators in dry cell batteries.

[0007] Furthermore, during battery operation, the volumes of the anode and cathode change. In addition, the battery may be exposed to elevated temperatures for extended periods of time. Thus, the separator must accommodate these volume variations during battery cycling while maintaining contact between the separator and the electrodes. It would therefore be desirable to improve the retention of interfacial contact between the solid electrodes and the solid separator in a dry cell battery during battery use, thus improving the cycling capability and lifespan of the battery.

[0008] It is an object of the present invention to address one or more of the above problems. In particular, it is an object of the present invention to provide an improved binder material for use in electrodes of metal-ion batteries, preferably for use in lithium-ion batteries. It is a particular object of the present invention to provide binder materials and electrodes that are more easily recyclable. It is also a particular object of the present disclosure to provide electrodes that exhibit improved interfacial compatibility with separators during the manufacture of metal-ion batteries, preferably lithium-ion batteries. It is also a particular object of the present invention to provide electrodes that exhibit improved interfacial compatibility with separators and that advantageously maintain interfacial contact during end use of the battery, thus improving the cycling capability and lifespan of the battery. It is a further object to provide electrodes with increased electronic conductivity.

[0009] The present invention is particularly directed to lithium-ion batteries. Thus, the terms "metal ion", "metal" and "metal-ion battery" as used in the preceding paragraphs and in the corresponding context below preferably refer to "lithium ion", "lithium" and "lithium-ion battery", respectively. However, the present invention is also applicable to other rechargeable metal-ion batteries, including those containing sodium, potassium, calcium, magnesium and aluminum, particularly sodium, magnesium and aluminum, and particularly sodium.

[0010] In a first aspect, the present invention provides an electrode comprised of an active material and a binder material, the binder material comprising a copolyester comprising repeat units derived from a diol, a dicarboxylic acid, and a poly(alkylene oxide), the binder material may further comprise a first metal ion-containing component selected from a conductive ceramic particulate material, and / or may further comprise additional metal ions from one or more sources other than the conductive ceramic particulate material.

[0011] It will be understood that the term "electrode comprised of" as used in the first aspect and in the corresponding context below refers to an electrode that includes an active material and a binder material, or that is obtained from a composition that includes an active material and a binder material.

[0012] Thus, in one embodiment, the electrode comprises an active material and a binder material. Optionally, the electrode consists essentially of the active material and the binder material. In other words, the electrode does not include any further components that contribute to the electrochemical activity of the electrode. Optionally, the electrode consists of the active material and the binder material.

[0013] In an alternative embodiment, the electrode is obtained from a composition comprising an active material and a binder material. The composition may further comprise a liquid solvent. Typically, the liquid solvent is removed from the composition once the electrode is formed.

[0014] Preferably, the binder material further comprises said first metal ion-containing component selected from an electrically conductive ceramic particulate material.

[0015] It should be understood that for utility in metal ion batteries, the metal of the first metal ion-containing component of the film is preferably the same as the metal of the additional metal ion (hereinafter also referred to as the second metal ion-containing component).

[0016] Preferably, the first metal ion-containing component is a first lithium ion-containing component, in which case the additional metal ion is preferably an additional lithium ion. Alternatively, the first metal ion-containing component is a first sodium ion-containing component, in which case the additional metal ion is preferably an additional sodium ion.

[0017] Thus, in a preferred embodiment, the first aspect of the invention provides an electrode constituted by an active material and a binder material, the binder material comprising said copolyester and a first metal ion-containing component selected from a conductive ceramic particulate material.

[0018] Preferably, the binder material comprises said additional metal ion, if present, preferably in the form of a second metal ion-containing component, preferably selected from a metal salt, preferably selected from a lithium salt or a sodium salt, preferably selected from a lithium salt.

[0019] Thus, in a preferred embodiment, the first aspect of the invention provides an electrode constituted by an active material and a binder material, the binder material comprising said copolyester and a metal ion-containing component selected from metal salts.

[0020] In a particularly preferred embodiment, the first aspect of the present invention provides an electrode constituted by an active material and a binder material comprising said copolyester, a first metal ion-containing component selected from a conductive ceramic particulate material, and a second metal ion-containing component selected from a metal salt, it being understood that the first and second metal ion-containing components are different from each other.

[0021] In a particularly preferred embodiment, the first aspect of the invention provides an electrode comprised of an active material and a binder material comprising said copolyester, a first lithium ion-containing component selected from a conductive ceramic particulate material, and a second lithium ion-containing component selected from a lithium salt, it being understood that the first and second lithium ion-containing components are different from each other.

[0022] In an alternative embodiment, the first aspect of the present invention provides an electrode comprised of an active material and a binder material, the binder material comprising said copolyester, a first sodium ion-containing component selected from a conductive ceramic particulate material, and a second sodium ion-containing component selected from a sodium salt, it being understood that the first and second sodium ion-containing components are different from each other.

[0023] The electrodes of the present invention may be cathodes or anodes. The electrodes of the present invention are more easily recyclable than known electrodes containing PVDF binders. The inventors have surprisingly found that the electrodes of the present invention exhibit good interfacial compatibility with subsequent separators, particularly solid separators in dry cell batteries. The inventors have surprisingly found that the electrodes of the present invention continue to have good interfacial contact during the final use of the battery.

[0024] The binder material comprises a copolyester comprising repeat units derived from a diol, a dicarboxylic acid, and a poly(alkylene oxide), and may further comprise a first metal ion-containing component selected from an electrically conductive ceramic particulate material, and / or may further comprise additional metal ions from one or more sources other than the electrically conductive ceramic particulate material.

[0025] As used herein, the term "copolyester" refers to a polymer containing ester linkages and derived from three or more comonomers. The copolyesters described herein are thermoplastic.

[0026] Suitable dicarboxylic acids for the copolyester include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acids (such as 2,5-, 2,6-, or 2,7-naphthalenedicarboxylic acid), and aliphatic dicarboxylic acids such as succinic acid, sebacic acid, adipic acid, and azelaic acid. Cycloaliphatic dicarboxylic acids may also be used. Other suitable dicarboxylic acids include 4,4'-diphenyldicarboxylic acid and hexahydroterephthalic acid. Preferably, the dicarboxylic acid used in the present invention is an aromatic dicarboxylic acid, preferably terephthalic acid or isophthalic acid, preferably terephthalic acid.

[0027] The copolyester preferably comprises at least one aromatic dicarboxylic acid, preferably terephthalic acid, isophthalic acid, or naphthalenedicarboxylic acid, and preferably terephthalic acid or isophthalic acid, and preferably terephthalic acid. In a first most preferred embodiment, the dicarboxylic acid component comprises only one aromatic dicarboxylic acid. In a second embodiment, the dicarboxylic acid component comprises a first aromatic dicarboxylic acid (preferably terephthalic acid or isophthalic acid, preferably terephthalic acid) and a second dicarboxylic acid. The second dicarboxylic acid may be selected from an aliphatic dicarboxylic acid such as succinic acid, sebacic acid, adipic acid, or azelaic acid, and in one embodiment, the second dicarboxylic acid is azelaic acid.

[0028] Suitable diols for the copolyester include acyclic, alicyclic and aromatic dihydroxy compounds. Preferred diols have 2 to 15 carbon atoms and include ethylene, propylene, isobutylene, tetramethylene, 1,4-pentamethylene, 2,2-dimethyltrimethylene, hexamethylene and decamethylene glycol, dihydroxycyclohexane, cyclohexanedimethanol, resorcinol, hydroquinone and 1,5-dihydroxynaphthalene. Aliphatic diols are preferred, especially acyclic aliphatic diols containing 2 to 8 carbon atoms, especially aliphatic diols containing 2 to 4 carbon atoms. Unbranched aliphatic diols are preferred. Preferably, the diol is selected from ethylene glycol, 1,3-propanediol and 1,4-butanediol, more preferably ethylene glycol and 1,4-butanediol, most preferably ethylene glycol. Cycloaliphatic (alicylic) glycols such as 1,4-cyclohexanedimethanol (CHDM) can also be used. Instead of the diol, the equivalent ester-forming derivatives of the diol can also be used. Preferably, the copolyester contains only one type of diol residue. In one embodiment, at least 90 mol %, preferably at least 95 mol %, preferably at least 98 mol %, and preferably at least 99 mol % of the diol fraction consists of one type of diol.

[0029] The poly(alkylene oxide) suitable for the copolyester is preferably C2-C 15 , preferably C2 to C 10 , preferably C2-C6 alkylene chains. The poly(alkylene oxide) may be selected from polyethylene glycol (PEG), polypropylene glycol (PPG), and poly(tetramethylene oxide) glycol (PTMO), preferably polyethylene glycol. Ethylene oxide terminated poly(propylene oxide) segments may also be used. In one embodiment, the copolyester comprises only one type of poly(alkylene oxide) residue. In an alternative embodiment, the copolyester comprises more than one type of poly(alkylene oxide) residue, such as a mixture of polyethylene glycol (PEG) and polypropylene glycol (PPG).

[0030] The number average molecular weight (M N ) is preferably about 200 g / mol to about 20,000 g / mol, preferably about 200 g / mol to about 6,000 g / mol, preferably about 200 g / mol to about 5,000 g / mol, preferably about 5,000 g / mol or less, preferably about 4,000 g / mol or less, preferably about 400 g / mol to about 3,900 g / mol, preferably at least about 500 g / mol, preferably about 500 g / mol to about 3,800 g / mol, most preferably about 500 g / mol to about 3,700 g / mol, preferably about 800 g / mol to about 3,600 g / mol, preferably about 1,000 g / mol to about 3,600 g / mol, preferably about 2,000 g / mol to about 3,500 g / mol, and preferably about 3,350 to about 3,450 g / mol, and preferably about 3,350 g / mol or about 3,450 g / mol. The number average molecular weight (M N The number average molecular weight (M) of the poly(alkylene oxide) is preferably at least about 200 g / mol, preferably at least about 400 g / mol, preferably at least about 500 g / mol, and preferably at least about 800 g / mol, for example at least about 1000 g / mol. N) is preferably about 20000 g / mol or less, preferably about 5000 g / mol or less, preferably about 4000 g / mol or less, preferably about 3800 g / mol or less, for example about 3700 g / mol or less.

[0031] It has been found that if the molecular weight of the poly(alkylene oxide) is too high, it becomes more difficult to copolymerize with the dicarboxylic acid and diol to form a copolyester that has a high enough solution viscosity to form a reliable film. Moreover, it has been found that if the molecular weight of the poly(alkylene oxide) is too high, the electrical conductivity may decrease.

[0032] Unless otherwise indicated by context, the term molecular weight as used herein refers to the number average molecular weight (M N )

[0033] Polydispersity Index, PDI (or Dispersity, D) is M W / M N It is defined as M W is the weight average molecular weight. The polydispersity index is a measure of the uniformity (or heterogeneity) of sizes of different macromolecules that comprise a polymer (which is a mixture of macromolecules of different sizes). A composition with a polydispersity index of 1 (i.e., monodisperse) consists of macromolecules (such as dendrimers) that each have the same size. Monodisperse compositions of macromolecules are usually made by nonpolymeric processes and are not usually called polymers.

[0034] The poly(alkylene oxide) of the copolyester preferably has a polydispersity index greater than 1, preferably at least about 1.01, preferably at least about 1.1, preferably at least about 1.2, and preferably about 2.0 or less, preferably about 1.8 or less, preferably about 1.6 or less, and preferably from about 1.01 to about 2.0, preferably from about 1.1 to about 1.8, and preferably from about 1.2 to about 1.6.

[0035] Copolyesters may be block (segmented) copolymers containing alternating random length sequences linked by ester bonds. Such copolyesters exhibit semicrystalline (or hard) segments derived from dicarboxylic acids and diols, and amorphous (or soft) segments derived from poly(alkylene oxide). For example, the hard segments consist of repeating units of [R1-OC(=O)-AC(=O)-O], where R1 is derived from an aliphatic diol and A is an aromatic ring (preferably phenyl or naphthyl) derived from an aromatic dicarboxylic acid as defined above. The soft segments consist of repeating units of [RO], where R is an alkylene chain from poly(alkylene oxide). The soft segments may be end-capped with the dicarboxylic acid via an ester bond.

[0036] In a further embodiment, the copolyesters are random copolymers in which the dicarboxylic acid, diol, and poly(alkylene oxide) units are arranged in a random sequence within the copolyester backbone.

[0037] Between the extremes of random and block copolymers are copolyesters, referred to herein as "blocky" copolymers. In blocky copolymers, the poly(alkylene oxide) units are interspersed among the dicarboxylic acid units to a greater extent than in block copolymers, so that the crystalline (or hard) segments are, on average, much shorter than in block copolymers. The arrangement of the comonomer units in the copolymer chain, and thus the degree of randomness of the copolyesters, can be described using conventional techniques known in the art, preferably as described herein. 13 The degree of randomness, B, can be determined by C NMR spectroscopy. Copolyesters can be characterized as block, blocky, or random copolyesters by quantifying the degree of randomness, B, with a value of 0 representing a pure block copolymer and a value of 1 representing a statistically random copolymer as defined by the Bernoulli model.

[0038] Preferably, B is in the range of about 0.1 to 1.0, preferably about 0.2 to about 0.95, preferably about 0.3 to about 0.9, preferably about 0.4 to about 0.8, for example about 0.5 to about 0.7. The copolyesters preferably have a value of B of at least about 0.1, preferably at least about 0.2, preferably at least about 0.3, and preferably at least about 0.4, for example at least about 0.5. The copolyesters preferably have a value of B of 1.0 or less, preferably about 0.95 or less, preferably about 0.9 or less, preferably about 0.8 or less, and preferably about 0.7 or less.

[0039] Preferably, the copolyesters of the present invention are "blocky" or random copolyesters.

[0040] More preferably, the copolyesters of the present invention are "blocky" copolyesters, obtainable by selecting the molecular weight of the poly(alkylene oxide)s as described herein.

[0041] It has been found that the molecular weight of the poly(alkylene oxide) has a significant effect on the arrangement of the comonomers in the copolyester and on the characterization of the copolymer as a block copolymer, block-like copolymer, or random copolymer. Thus, poly(alkylene oxide)s with lower molecular weight favor the formation of random copolymers, and poly(alkylene oxide)s with higher molecular weight favor the formation of block copolymers. Block copolymers usually exhibit a stronger tendency to crystallize and a higher melting point than the corresponding random copolymers. In the present invention, higher melting temperatures are preferably avoided, since they require higher processing temperatures and increase the risk of degradation. Furthermore, in the present invention, it is preferable to avoid the increased tendency of crystallization of pure block copolymers, since this may hinder the mobility of metal ions within the copolymer structure, which may reduce its electrical conductivity.

[0042] The poly(alkylene oxide) is preferably about 0.1 to about 80% by weight, preferably about 5 to about 78% by weight, preferably about 10 to about 75% by weight, preferably about 12 to 65% by weight, preferably about 15 to about 60% by weight, preferably about 16 to about 55% by weight of the total weight of the copolyester.

[0043] Preferably, the poly(alkylene oxide) is at least about 0.1 wt.%, preferably at least about 5 wt.%, preferably at least about 10 wt.%, preferably at least about 12 wt.%, preferably at least about 15 wt.%, preferably at least about 16 wt.%, preferably not more than about 80 wt.%, preferably not more than about 78 wt.%, preferably not more than about 75 wt.%, preferably not more than about 65 wt.%, preferably not more than about 60 wt.%, preferably not more than about 55 wt.% of the total weight of the copolyester.

[0044] When the copolyester comprises repeat units derived from a diol (preferably ethylene glycol), terephthalic acid, and a poly(alkylene oxide), the poly(alkylene oxide) is preferably present in an amount of from about 5 to about 30 weight percent, preferably from about 10 to about 25 weight percent, and preferably from about 15 to about 20 weight percent of the total weight of the copolyester.

[0045] When the copolyester comprises repeat units derived from a diol (preferably ethylene glycol), isophthalic acid, and a poly(alkylene oxide), the poly(alkylene oxide) is preferably present in an amount of from about 35 to about 65 weight percent, preferably from about 40 to about 60 weight percent, and preferably from about 45 to about 55 weight percent of the total weight of the copolyester.

[0046] The amount of copolyester present in the binder material is preferably about 99.9% by weight or less, preferably about 95% by weight or less, preferably about 92% by weight or less, preferably about 90% by weight or less of the total weight of the binder material. Preferably, the amount of copolyester present in the binder material is at least about 40% by weight, preferably at least about 50% by weight, preferably at least about 65% by weight, preferably about 80% by weight of the total weight of the binder material. Thus, the amount of copolyester present is preferably about 40% by weight to about 99.9% by weight, preferably about 50% by weight to about 95% by weight, preferably about 65% by weight to about 92% by weight, preferably about 80% by weight to about 90% by weight of the total weight of the binder material.

[0047] It is preferred that the copolyester be the only polyester present in the binder material.

[0048] As noted above, the binder material preferably includes a first lithium-ion-containing component selected from an electrically conductive ceramic particulate material. There may be more than one electrically conductive ceramic particulate material.

[0049] It is understood by those skilled in the art that ceramic materials are inorganic non-metallic solids containing both metallic and non-metallic elements that are formed or densified by heating at high temperatures. Ceramic materials are typically hard, brittle, corrosion resistant, have low chemical reactivity and high melting points. The ceramic materials referred to herein may be crystalline or glassy. The ceramic particulate materials used in the present invention are electrically conductive. The present invention is described below primarily with respect to lithium ion-containing electrically conductive ceramic particulate materials, but the technical principles are generally applicable to other metal ion-containing electrically conductive ceramic particulate materials.

[0050] In particular, any suitable lithium-ion-containing conductive ceramic particle material can be used, such as NASICON-type ceramic particle materials (such as lithium-ion-containing conductive glass ceramic particle materials), LISICON-type ceramic particle materials, perovskite-type oxide ceramic particle materials, garnet-type oxide ceramic particle materials, lithium phosphorus oxynitride (LIPON)-type ceramic particle materials, and lithium aluminum silicate (LAS) ceramic particle materials.

[0051] As is known in the art, NASICON (sodium superionic conductor) materials refer to solid families having the chemical formula Na 1+x Zr2Si x P 3-x O 12 and similar compounds in which Na, Zr, and / or Si are replaced by isovalent elements. In the context of the most preferred embodiments of the present invention, sodium is replaced by lithium. Particularly suitable lithium-containing NASICON-type ceramic particle materials have the general formula LiM y (PO4)3, where M represents a polyvalent metal ion in the above formula. For example, M can be selected from one or more of Al, Si, Ti, Zr, Ge, Sn, and Hf. Other suitable lithium-containing NASICON-type ceramic particle materials have the general formula Li 1+x M x Ti 2-x (PO4)3 (LATP), where M represents a trivalent cation selected from one or more of Al, Sc, Y, and La in the above formula. Other suitable lithium-containing NASICON-type ceramic particle materials can have, for example, the general formula Li 1+x Al x Ge 2-x (PO4)3 (LAGP) when x is 0.5.

[0052] Particularly preferred is a lithium-ion-containing conductive glass ceramic particle material having a NASICON structure. A preferred granular material is commercially available from Ohara Inc. under the trade name "LICGC". A preferred particle material is commercially available from Ohara Inc. as LICGC (trademark) PW-01 powder, which is Li1+x+y Al x Ti 2-x S y P 3-y O 12 and a composition of Li2O-Al2O3-SiO2-P2O5-TiO2. A further preferred granular material is commercially available from Ohara Inc. as LICGC™ AG-01, which contains Li 1+x+y Al x (Ti,Ge) 2-x S y P 3-y O 12 It is understood to have a primary crystalline phase of Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2.

[0053] As known in the art, LISICON (lithium superionic conductor) material has the chemical formula Li 2+2x Zinc 1-x It refers to a family of solids having GeO4. As with NASICON-type materials, other elements (usually isovalent elements) may replace Li, Zn, and / or Ge. The preferred LISICON-type particulate material is Li 2+2x Zinc 1-x Ge4O 16 , Li 14 ZnGeO 16 , Li (3+x) Ge x V (1-x) O4, Li (4-x) S (1-x) P x O4, and formula Li (4-x) Ge (1-x) P x S4Li 10 GeP2S 12 where x is between 0 and 1.

[0054] A suitable perovskite oxide particle material is Li 3x La (2 / 3)-x TiO3(LLTO) and Li 3x La 1 / 3-x It may be selected from TaO3.

[0055] Suitable garnet-type oxide particle materials have the general formula Li 7-3y-x La3Zr 2-x M1 y M2 x O 12 (wherein M1 represents a trivalent cation such as Al and Ga, M2 represents a pentavalent cation such as Nb and Ta, and x≧0 and y≦2), Li5La3M2O 12 (where M represents Nb and / or Ta), Li6ALa2M2O 12 (wherein A represents Ca, Sr, and / or Ba, and M represents Nb or Ta), or Li 6.5 La 2.5 Ba 0.5 ZrTaO 12 may have:

[0056] Suitable LIPON type ceramic particle materials are of the general formula LiPON, such as Li2PO2N x PO y N z may have:

[0057] A suitable LAS ceramic particle material may be selected from AlLiO6Si2.

[0058] With regard to the sodium ion-containing ceramic particle material, NASICON-type ceramic particle materials (such as sodium ion-containing conductive glass-ceramic particle materials), beta-alumina and beta''-alumina phases Na2O.nAl2O3 (where 5≦n≦11), rare earth sodium silicates, and Na-ion conductive oxyhalide glasses are particularly suitable. Suitable NASICON-type ceramic particle materials have the general formula Na3Zr2Si2PO 12 , NaTi2(PO4)3, NaGe2(PO4)3, or Na 1+x [Sn x Ge 2-x The preferred rare earth sodium silicates are oxides of the NASICON structure, which may have the general formula Na5MSi4O 12where M is Y, Sc, Lu, and / or any trivalent rare earth cation. A suitable Na-ion conducting oxyhalide glass may be NaI-NaCl-Na2O-B2O3.

[0059] Preferably, the volume distribution median particle size (equivalent spherical diameter corresponding to 50% of the volume of the total particles, read on a cumulative distribution curve relating volume percentage to particle size, often referred to as the "Dv50" or "D50" value) of the conductive ceramic particle material is in the range of 0.01-5 μm, preferably 0.05-3 μm, preferably 0.1-2 μm, preferably 0.2-1.5 μm, preferably 0.4-1.0 μm. The particle size may be measured by laser light diffraction (preferably Fraunhofer diffraction). A particularly preferred method utilizes a Mastersizer (e.g. 3000) available from Malvern. The median particle size may be determined by plotting a cumulative distribution curve representing the percentage of particle volume below a chosen particle size and measuring the 50th percentile.

[0060] When present, the amount of said metal ion-containing conductive ceramic particulate material in the binder material is preferably about 60% by weight or less, preferably about 50% by weight or less, preferably about 35% by weight or less, preferably about 20% by weight or less, and preferably at least about 0.1% by weight, preferably at least about 5% by weight, preferably at least about 8% by weight, preferably at least about 10% by weight of the total weight of the binder material. Thus, the amount of conductive ceramic particulate material present is preferably from about 0.1% to about 60% by weight, preferably from about 5% to about 50% by weight, preferably from about 8% to about 35% by weight, preferably from about 10 to about 20% by weight of the total weight of the binder material.

[0061] The metal ion containing conductive ceramic particulate material is held within a polymer matrix of a binder material.

[0062] As mentioned above, the binder material preferably includes additional metal ions from one or more sources other than the conductive ceramic particle material. When the conductive ceramic particle material is a lithium ion-containing conductive ceramic particle material, the composition preferably includes additional lithium ions from one or more sources other than the conductive ceramic particle material. When the conductive ceramic particle material is a sodium ion-containing conductive ceramic particle material, the composition preferably includes additional sodium ions from one or more sources other than the conductive ceramic particle material. These additional metal ions are referred to herein as second metal ion components, such as a second lithium ion component or a second sodium ion component. It should be understood that the first metal ion-containing component and the second metal ion component are different from each other. The second metal ion component is preferably a metal ion-containing component selected from metal salts. The present invention is described below mainly with respect to lithium salts, but the technical principles are generally applicable to other metal salt materials.

[0063] Any suitable lithium salt may be used. One or more different types of lithium salt may be used. Preferably, the lithium salt is selected from lithium salts suitable for use in lithium ion batteries, such as lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium thiocyanate (LiSCN), lithium hexafluoroarsenate (LiAsF6), lithium trifluoromethanesulfonate (LiCF3SO3), lithium bromide (LiBr), lithium iodide (LiI), lithium bis(trifluoromethanesulfonimide) (LiN(CF3SO2)2), lithium tris(trifluoromethylsulfonyl)methide (LiC(CF3SO2)3), lithium orthosilicate, lithium trifluoroacetate (LiCF3CO2), and lithium bis(fluorosulfite)amide (LiN(FO2S)2).

[0064] When electrodes are formed using solvent casting techniques, it is preferred that the metal ions are derived from a metal salt that has high solubility in the solvent used in the solution re-casting step. Thus, for lithium ion batteries, a particularly preferred lithium salt is lithium trifluoromethanesulfonate (LiCF3SO3).

[0065] The metal salts (including the preferred lithium salts) may be selected from: (i) an aromatic carboxylic acid, preferably an aromatic dicarboxylic acid, preferably terephthalic acid or isophthalic acid; (ii) an aliphatic carboxylic acid, preferably comprising an aliphatic dicarboxylic acid, such as acetic acid, glycolic acid, or succinic acid; (iii) carbonic acid, (iv) phenolic acids, preferably salicylic acid; (v) mineral acids such as perchloric acid or phosphoric acid, in particular phosphoric acid, and (vi) Boric acid, preferably bis(oxalic)boric acid.

[0066] Optionally, the metal salt is selected from metal salts (i) to (v) above.

[0067] Thus, suitable lithium salts include dilithium terephthalate (DLTA), dilithium isophthalate, lithium glycolate, lithium benzoate, lithium acetate, lithium carbonate, lithium perchlorate, lithium orthosilicate, lithium phosphate, lithium salicylate, lithium succinate, and lithium bis(oxalato)borate.

[0068] Preferably, the metal salt is an organometallic salt.

[0069] In a preferred embodiment, the metal salt is the salt of the aromatic dicarboxylic acid from which the copolyester is obtained. Thus, in the case of the preferred copolyester obtained from terephthalic acid, the lithium salt is preferably selected from monolithium terephthalate or dilithium terephthalate, preferably dilithium terephthalate. The inventors have found that dilithium terephthalate is particularly preferred for reasons of thermal stability and cost. In the case of the preferred copolyester obtained from isophthalic acid, the lithium salt is preferably selected from monolithium isophthalate or dilithium isophthalate, preferably dilithium isophthalate.

[0070] Other preferred metal salts may be selected from the alkoxylate esters of the acids mentioned above, especially carboxylic acids, especially dicarboxylic acids, especially aromatic dicarboxylic acids, especially terephthalic acid. Such alkoxylate esters are preferably from aliphatic diols, preferably C 2-10 From aliphatic diols, preferably C 2-6 It is derived from an aliphatic diol, preferably from a C2, C3, or C4 aliphatic diol, more preferably from ethylene glycol, 1,3-propanediol, and 1,4-butanediol, more preferably from ethylene glycol.

[0071] A particularly suitable lithium salt has the formula (I) below, and is referred to herein as dilithium bishydroxyethyl terephthalate (DL-BHET). [ka]

[0072] Preferably, the lithium salt is selected from lithium trifluoromethanesulfonate (LiCF3SO3), dilithium terephthalate or dilithium bishydroxyethyl terephthalate. Preferably, the lithium salt is selected from dilithium terephthalate.

[0073] For sodium-containing embodiments of the present invention, any suitable sodium salt may be used. One or more different types of sodium salt may be used. It is understood that the preferences and elements described for lithium salts apply equally to sodium salts, except that lithium ions are replaced by sodium ions. Preferably, the sodium salt is selected from sodium nitrate (NaNO3), sodium perchlorate (NaClO4), sodium tetrafluoroborate (NaBF4), sodium hexafluorophosphate (NaPF6), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI), sodium bis(trifluoromethane)sulfonimide (Na[N(CF3SO2)2]), sodium hexafluoroarsenate(V) (NaAsF6), sodium bis(oxalatoborate) ("NaBOB"), sodium halides (NaX) (where X = Cl, Br, or I), sodium thiocyanate (NaSCN), sodium pentacyanopropenide (NaPCPI), sodium tetracyanopyrrolate (NaTCP), and sodium tricyanoimidazolate (NaTIM).

[0074] In one embodiment, the metal ions of the second metal ion component are present in and retained within the polymer matrix of the binder material by interactions between metal cations and polarizable electronegative oxygen atoms of the copolyester, preferably at least the electronegative oxygen atoms of the polyalkylene oxide units.

[0075] In a preferred embodiment, the metal ions of the second metal ion component are retained in the polymer matrix of the binder material by interaction between the metal cations and the anions of the metal salt. Thus, in this embodiment, the binder material comprises a metal salt. Preferably at least a portion, preferably at least 50% by weight, preferably at least 60% by weight, preferably at least 70% by weight, preferably at least 80% by weight, preferably at least 90% by weight, preferably at least 95% by weight, preferably at least 99% by weight, and preferably substantially all, of the second metal ion component is in the form of a metal salt. The metal salt is selected from the metal salts mentioned above, and the preferences mentioned above apply here. Thus, in this preferred embodiment, the metal salt is retained in the polymer matrix. In this embodiment, the metal salt is not part of the polymer backbone, i.e. the metal salt is not polymerized in the copolyester. In other words, in this preferred embodiment, the anions of the metal salt are not covalently bonded to the copolyester. In the preferred embodiment described above, where the metal salt is a salt of the same aromatic dicarboxylic acid from which the copolyester is derived, the metal-containing copolyester films described herein exhibit excellent thermal stability that is believed to result from matching the morphology of the copolyester with the morphology of the metal salt.

[0076] The amount of metal ions of the second metal ion component in the composition is preferably effective to provide a metal:O molar ratio of from about 5:1 to about 1:50, preferably from about 4:1 to about 1:50, preferably from about 3:1 to about 1:50, preferably from about 2:1 to about 1:50, preferably from about 1:1 to about 1:40, preferably from about 1:2 to about 1:30, preferably from about 1:4 to about 1:25, where the number of O atoms in this ratio is defined as the number of O atoms in the poly(alkylene oxide) residue and the number of metal atoms in this ratio is defined as the number of metal atoms provided by the additional metal ions (i.e., the second metal ion component, excluding the first metal ion-containing component).

[0077] When present, the amount of the second metal ion component (i.e., preferably the metal salt) is preferably about 40 wt.% or less, preferably about 10 wt.% or less, preferably at least about 0.1%, preferably at least about 1%, and preferably from about 0.1 wt.% to about 40 wt.%, preferably from about 1 wt.% to about 10 wt.%, of the total weight of the binder material.

[0078] When the binder material includes the first metal ion-containing component and the second metal ion component, the total weight of the first metal ion-containing component and the second metal ion component is preferably about 60% by weight or less, preferably about 50% by weight or less, preferably about 35% by weight or less, preferably about 20% by weight or less, and preferably at least 0.1% by weight, preferably at least about 5% by weight, preferably at least about 8% by weight, preferably at least about 10% by weight of the total weight of the binder material. Thus, the total amount of the first metal ion-containing component and the second metal ion component materials present is preferably about 0.1% by weight to about 60% by weight, preferably about 5% by weight to about 50% by weight, preferably about 8% by weight to about 35% by weight, preferably about 10% by weight to about 20% by weight of the total weight of the binder material.

[0079] The electrode of the present invention may further comprise any other additives conventionally used in the manufacture of polyester compositions or polyester films. Thus, agents such as antioxidants, heat stabilizers, and antifoaming agents may be incorporated as necessary. Such additives may be introduced into the electrode in a conventional manner. For example, the additive(s) may be introduced by mixing with the monomer reactants from which the copolyester is obtained, or the additive(s) may be mixed with the composition by tumbling or dry mixing, or by compounding in an extruder, then cooling and typically grinding into granules or chips. Masterbatching techniques may also be used.

[0080] In a preferred embodiment, the electrode includes an antioxidant. A variety of antioxidants can be used, including antioxidants that function by scavenging radicals or by decomposing peroxides. Suitable radical-scavenging antioxidants include hindered phenols, secondary aromatic amines, and hindered amines such as Tinuvin™ 770 (Ciba-Geigy). Suitable peroxide-decomposing antioxidants include trivalent phosphorus compounds such as phosphonites, phosphites (e.g., triphenyl phosphate and trialkyl phosphites), and thiosynergics (e.g., esters of thiodipropionic acid such as dilauryl thiodipropionate). Hindered phenol-based antioxidants are preferred. A particularly preferred hindered phenol is tetrakis-(methylene 3-(4'-hydroxy-3',5'-di-t-butylphenylpropionate)methane, available commercially as Irganox™ 1010 (Ciba-Geigy). Other suitable commercially available hindered phenols include Irganox™ 1035, 1076, 1098, and 1330 (Ciba-Geigy), Santanox™ R (Monsanto), Cyanox™ antioxidant (American Cyanamid), and Goodrite™ antioxidant (BF Goodrich). The concentration of antioxidant present in the electrode is preferably in the range of 50 ppm to 5000 ppm, more preferably in the range of 300 ppm to 1500 ppm, particularly in the range of 400 ppm to 1200 ppm, especially in the range of 450 ppm to 600 ppm, based on the weight of the electrode. A mixture of more than one antioxidant may be used, in which case the total concentration is preferably in the above range. The antioxidant may be incorporated into the copolyester, which incorporation may be achieved by conventional techniques and preferably by mixing with the monomeric reactants from which the copolyester is obtained, prior to polycondensation, particularly at the end of the direct esterification or transesterification reaction.

[0081] In a further preferred embodiment, the binder material comprises an inorganic particle filler, preferably selected from semi-metal oxides (such as alumina, titania, zirconia, zinc oxide, talc, and silica), calcined china clay, alkali metal salts (such as calcium and barium carbonates and sulfates), and non-conductive ceramic particle materials. The inorganic particle filler should have a particle size smaller than the final electrode thickness, and preferably has a particle size of 10 μm or less, preferably about 5 μm or less, preferably about 2 μm or less, preferably in the range of about 0.5 μm to about 2.0 μm. It should be understood that the identity of the inorganic particle filler (or indeed any other additive of the conventional additive) is a different entity from the first or second metal ion-containing components described above. In particular, the inorganic particle filler (or any other additive of the conventional additive) does not contain the metal ions of the first or second metal ion-containing components described above, and therefore, the inorganic particle filler is referred to herein as a "passive filler" because the inorganic particle filler cannot directly transport the metal ions. Nevertheless, it has surprisingly been found that such passive fillers enhance the ionic conductivity produced by the first or second metal ion-containing components.

[0082] Thus, in a preferred embodiment of the first aspect of the present invention, there is provided an electrode constituted by an active material and a binder material, the binder material comprising a copolyester comprising repeat units derived from a diol, a dicarboxylic acid, and a poly(alkylene oxide), the binder material further comprising a passive filler.

[0083] In a further preferred embodiment of the first aspect of the present invention, there is provided an electrode constituted by an active material and a binder material, the binder material comprising a copolyester comprising repeat units derived from a diol, a dicarboxylic acid, and a poly(alkylene oxide), the binder material further comprising a first metal ion-containing component selected from an electrically conductive ceramic particulate material, and a passive filler.

[0084] In a further preferred embodiment of the first aspect of the present invention, there is provided an electrode comprised of an active material and a binder material, the binder material comprising a copolyester comprising repeat units derived from a diol, a dicarboxylic acid, and a poly(alkylene oxide), the binder material further comprising a first metal ion-containing component selected from a conductive ceramic particulate material, a passive filler, and additional metal ions from one or more sources other than the conductive ceramic particulate material and other than the passive filler.

[0085] Inorganic particle fillers are routinely added to polyester films to improve handling and windability during manufacture and downstream processing, and for such purposes, fillers are usually used in relatively small amounts, so that the total weight of fillers is generally about 2.5% by weight or less, preferably about 2.0% by weight or less, preferably about 1.0% by weight or less, more typically about 0.6% by weight or less, and preferably about 0.3% by weight or less, based on the total weight of the copolyester film. However, in the present invention, passive fillers are preferably used in an amount of at least 5% by weight, preferably at least about 7% by weight, preferably at least about 10% by weight, and preferably about 5% to about 20% by weight, preferably about 7% to about 20% by weight, preferably about 7% to about 15% by weight, based on the total weight of the binder material.

[0086] The binder material is present in an amount of preferably from about 0.1 to about 25 wt %, preferably from about 0.2 to about 20 wt %, preferably from about 0.4 to about 10 wt %, preferably from about 0.5 to about 7 wt %, preferably from about 1 wt % to about 6 wt %, preferably from about 2 to about 5 wt %, of the total weight of the electrode.

[0087] As used herein, the term "active material" refers to an electrochemically active material that can store metal ions (preferably lithium ions in lithium ion batteries) and reversibly release the metal ions in a controlled manner. Any suitable electrochemically active material may be used.

[0088] It should be understood that the binder material may have some degree of electrochemical activity, but the active material is a separate entity from the binder material described hereinabove, and from each of the copolyester, first metal ion-containing component, and second metal ion-containing component described above.

[0089] When the electrode is an anode, the active material is preferably selected from graphite and / or lithium titanate (LTO).

[0090] If the electrode is a cathode, the active material is preferably selected from lithium or mixed oxides of lithium and other metal(s), in particular lithium titanate (LTO), lithium iron phosphate (LiFePO4, also known as LFP), and / or lithium nickel manganese cobalt oxide (LiNiMnCoO2, also known as NMC).

[0091] The active material is preferably in the form of fine particles.

[0092] The active material is preferably present in an amount of about 75 to about 99.1% by weight, preferably about 80 to about 95% by weight, of the total weight of the electrode. If the electrode is an anode, the active material is preferably present in an amount of about 90 to about 95% by weight, for example about 93% by weight, of the total weight of the electrode.

[0093] The active material (comprised of the copolyester and the first metal ion-containing component and / or second metal ion component, if present) and binder material are the major components of the electrode and preferably comprise at least about 75%, preferably at least about 80%, preferably at least about 85%, preferably at least about 90%, preferably at least about 95%, and preferably at least about 98% of the total weight of the electrode.

[0094] The electrodes of the present invention may further comprise a conductive additive, such as a carbon material. Thus, a carbon material, such as carbon black (e.g., acetylene black) or graphite, may be incorporated as needed. A particularly preferred carbon black is commercially available as Super-P (Timcal Co., Ltd.). The conductive additive may be present in an amount of about 0.5 to about 10% by weight, preferably about 1 to about 6% by weight, and preferably about 2.5 to about 5% by weight, of the total weight of the electrode.

[0095] As mentioned above, the electrode may be obtained from a composition including an active material, a binder material, and a liquid solvent. Suitable liquid solvents include N-methyl-2-pyrrolidone (NMP), acetonitrile (ACN), tetrahydrofuran (THF), dimethylformamide (DMF), dimethylsulfoxide (DMSO), dimethylcarbonate (DMC), ethylene carbonate (EC), propylene carbonate (PC), dimethoxyethane (DME), methyl formate (MF), nitromethane (NM), diethyl carbonate (DEC), toluene, water, ethanol, acetone, isopropyl alcohol, methanol, ethyl alcohol, and ethyl acetate.

[0096] The electrode may be a film or a coating. In one embodiment, the electrode is a film. The film may be an oriented film, most preferably a biaxially oriented film. The film may be a free-standing film or may be cast onto a supporting base. Preferably, the film is cast onto the supporting base. In an alternative preferred embodiment, the electrode is coated onto the supporting base. The supporting base may itself be a component of the solid-state battery, such as a current collector or separator. If the electrode is coated onto the current collector, the electrode is in electrical contact with the current collector by being deposited on the current collector. If the electrode is coated onto the separator, the electrode is in interfacial contact with the separator by being deposited on the separator.

[0097] According to a second aspect of the present invention, there is provided a binder material comprising a copolyester comprising repeat units derived from a diol, a dicarboxylic acid, and a poly(alkylene oxide), the binder material may further comprise a first metal ion-containing component selected from an electrically conductive ceramic particulate material, and / or may further comprise additional metal ions from one or more sources other than the electrically conductive ceramic particulate material.

[0098] Also provided is the use of a binder material in a composition to form an electrode, the binder material comprising a copolyester comprising repeat units derived from a diol, a dicarboxylic acid, and a poly(alkylene oxide), and the binder material may further comprise a first metal ion-containing component selected from a conductive ceramic particulate material, and / or may further comprise additional metal ions from one or more sources other than the conductive ceramic particulate material.

[0099] The preferences and elements discussed in relation to the first aspect apply equally to the second aspect.

[0100] According to a third aspect of the present invention there is provided a method for manufacturing an electrode as described in the first aspect herein, the method comprising the steps of: (i) reacting the diol with the dicarboxylic acid or its ester (preferably a lower alkyl (C 1-4 ) ester, preferably a dimethyl ester) to form a bis(hydroxyalkyl) ester of the dicarboxylic acid; (ii) polymerizing the bis(hydroxyalkyl) ester of the dicarboxylic acid in a polycondensation reaction in the presence of a poly(alkylene oxide) to form a copolyester; (iii) optionally incorporating, during synthesis of the copolyester of steps (i) and / or (ii) and / or during a subsequent compounding or mixing step with a separate copolyester, the first metal ion-containing component selected from an electrically conductive ceramic particulate material, and optionally incorporating the additional metal ions from one or more sources other than the electrically conductive ceramic particulate material; (iv) providing the copolyester product from step (ii) or (iii) as a binder material; (v) mixing the active material and the binder material to form a composition; (vi) forming an electrode from the composition, preferably by solvent casting a dispersion or solution comprising the composition; Includes.

[0101] The copolyesters described herein can be synthesized according to conventional techniques for the manufacture of polyester materials. Thus, the copolyesters can be made by a first step of direct esterification or transesterification, followed by a second step of polycondensation. In a direct esterification embodiment, diols and dicarboxylic acids are reacted directly in the presence of a base (e.g., sodium hydroxide) at elevated temperature (usually about 150-260° C.) and pressure (usually about 40 psi), and the water by-product of the direct esterification reaction is distilled off to form a bis(hydroxyalkyl)carboxylate. Once the direct esterification reaction is complete, a stabilizer (e.g., phosphoric acid) is added to neutralize the base. In an alternative embodiment, the copolyesters are prepared by an esterification route, which preferably comprises an ester of a dicarboxylic acid (suitably a lower alkyl (C 1-4The process involves heating a bis(hydroxyalkyl) ester, preferably a dimethyl ester, with a molar excess of a diol in the presence of a basic esterification catalyst (e.g., manganese(II) acetate tetrahydrate, Mn(OAc)2·4H2O) at elevated temperature (usually in the range of about 150-260 °C) where the methanol by-product of the transesterification reaction is distilled off to form a bis(hydroxyalkyl) carboxylate. Polymerization is accomplished in a polycondensation step carried out using a suitable catalyst, usually antimony trioxide, at elevated temperature (usually about 290 °C), usually under reduced pressure (e.g., about 1 mm Hg), with continuous distillation of the by-product(s). Since the dicarboxylic acid or dicarboxylic acid ester starting material usually reacts selectively with the diol rather than the poly(alkylene oxide), the poly(alkylene oxide) may be present at the start of the synthesis procedure, especially as the molecular weight of the poly(alkylene oxide) increases. However, preferably, the poly(alkylene oxide) is added at the start of the polycondensation step.

[0102] Preferably, the synthesis procedure further comprises a solid state polymerization (SSP) step to increase the molecular weight of the copolyester and to increase and / or complete the polymerization of the poly(alkylene oxide) into the copolyester.

[0103] The product of the polycondensation reaction (step (ii)) is therefore preferably subjected to an SSP step. The solid state polymerization can be carried out in a fluidized bed, e.g. fluidized with nitrogen, or in a vacuum fluidized bed using a rotary vacuum dryer. Suitable solid state polymerization techniques are disclosed, for example, in EP-A-0419400, the disclosure of which is incorporated herein by reference. Thus, the SSP is usually carried out at a temperature close to the crystalline melting point (T M ) is 10 to 50°C below the glass transition temperature (T g ) (or, if the copolyester exhibits multiple glass transition temperatures, above the highest glass transition temperature). An inert atmosphere of dry nitrogen or vacuum is used to prevent degradation. In a preferred embodiment, the solid state polymerization is carried out at 220° C. under vacuum for 16 hours.

[0104] The optional first metal ion-containing component and the optional second metal ion-containing component may be introduced into the copolyester alone or together. When introduced alone, the first metal ion-containing component and the second metal ion-containing component may be introduced simultaneously or sequentially. When either or both of the first and second metal ion-containing component(s) contain multiple different compounds, the multiple compounds may be introduced into the copolyester alone or together, and when introduced alone, the multiple compounds may be introduced simultaneously or sequentially.

[0105] In one embodiment, referred to herein as embodiment A1, the first and second metal ion-containing components are introduced into the copolyester during synthesis of the copolyester in steps (i) and / or (ii). Preferably, the first and second metal ion-containing components are added to one or more of the reactants or reaction mixtures at the beginning of the synthesis procedure. Alternatively, the first and second metal ion-containing components are added to the reaction product of direct esterification or transesterification step (i) prior to the polycondensation stage (ii).

[0106] In a second embodiment, referred to herein as Embodiment A2, the first and second metal ion-containing components are introduced into the copolyester in separate combining or mixing steps.

[0107] In a third embodiment, herein referred to as embodiment A3, the first and second metal ion-containing components are introduced into the copolyester during different steps, e.g., the second metal ion-containing component is introduced during the synthesis of the copolyester in steps (i) and / or (ii) (preferably added to one or more of the reactant(s) or reaction mixture at the start of the synthesis) and the first metal ion-containing component is introduced during a separate combining or mixing step.

[0108] The electrodes can be formed by conventional solvent casting techniques well known in the art. Generally speaking, the process involves forming a dispersion including the binder material, the active material, and a liquid solvent. Suitable liquid solvents include N-methyl-2-pyrrolidone (NMP), acetonitrile (ACN), tetrahydrofuran (THF), dimethylformamide (DMF), dimethylsulfoxide (DMSO), dimethylcarbonate (DMC), ethylene carbonate (EC), propylene carbonate (PC), dimethoxyethane (DME), methyl formate (MF), nitromethane (NM), diethyl carbonate (DEC), toluene, water, ethanol, acetone, isopropyl alcohol, methanol, ethyl alcohol, and ethyl acetate.

[0109] The type of mixing vessel, the duration of the dispersing step, and the temperature of the dispersing step vary depending on the type of copolyester and liquid solvent used. Typically, the temperature used is between about 22° C. and about 100° C. Typically, the duration of the dispersing step is several hours, for example, between about 6 and 48 hours, between about 10 and 30 hours, between about 12 and 24 hours.

[0110] The optional first metal ion-containing component and the optional second metal ion-containing component may already be present in the copolyester that is contacted with the liquid solvent to form the dispersion. Alternatively, the first and second metal ion-containing components may be mixed with the copolyester dispersion, and in this embodiment, the first and second metal ion-containing components may be introduced into the dispersion alone or together. When introduced alone, the first and second metal ion-containing components may be introduced simultaneously or sequentially. When either or both of the first and second metal ion-containing components contain multiple different compounds, the multiple compounds may be introduced alone or together, and when introduced alone, the multiple compounds may be introduced simultaneously or sequentially.

[0111] The active material may be introduced into the dispersion alone or together with the components of the binder material. When the active material contains multiple different compounds, the multiple compounds may be introduced alone or together, and when introduced alone, the multiple compounds may be introduced simultaneously or sequentially.

[0112] In this manner, a composition is formed that includes the active material and the binder material.

[0113] The composition is then cast into a film or coated onto a supporting base. The cast film or coating is then appropriately dried to remove residual solvent. Typically, the cast film or coating is dried at a temperature of about 50°C to about 170°C, preferably about 80°C to 160°C. It should be understood that the drying step may include multiple (e.g., at least two) drying steps over different temperature ranges to reduce the amount of residual solvent. Once dried, the cast film may be removed from the supporting base for further processing and incorporated into a battery as an electrode.

[0114] In a particularly preferred method of manufacture, the composition is cast or coated onto a supporting base which is itself a component of the battery, in particular a current collector or separator, i.e. the electrode is formed in situ during battery manufacture. Thus, in a preferred embodiment, the battery's electrode is formed in situ during battery manufacture by casting the electrode composition onto a current collector. The composite structure of electrode and current collector then undergoes subsequent processing to manufacture the battery. In an alternative embodiment, the battery's electrode is formed in situ during battery manufacture by casting the electrode onto a separator. The composite structure of electrode and separator then undergoes subsequent processing to manufacture the battery.

[0115] The present invention further provides an electrode produced by the method of the third aspect.

[0116] The preferences and elements discussed in relation to the first and second aspects apply equally to the third aspect.

[0117] According to a fourth aspect of the present invention, there is provided an assembly comprising a current collector and an electrode, the electrode being as described in the first aspect or being an electrode obtained from the method of the third aspect.

[0118] It should be understood that the electrodes may be deposited on the surface of the current collector, for example, by casting or coating the resulting composition directly onto the surface of the current collector.

[0119] Any suitable current collector may be used, such as any suitable anode current collector and / or cathode current collector.

[0120] Suitable anode and / or cathode current collectors are disclosed, for example, in UK Application No. 2106834.1, the disclosure of which is incorporated herein by reference. In particular, the anode and / or cathode current collectors may be selected solely from current collectors comprising a biaxially oriented polymeric substrate layer (preferably, the polymeric substrate layer is a polyester, preferably PET or PEN), and a first metal layer on a side of the polymeric substrate layer, the polymeric substrate layer having a positive thermal expansion (preferably greater than 0% and less than or equal to 3.0%, preferably 0.1% to 2.0%, preferably 1.0% to 1.5%, in each of the transverse direction (TD) and machine direction (MD) in air at 200° C.) 0.2% to 1.5%), the polymer substrate layer has a thickness of 12 μm or less (preferably 1.0 to 12.0 μm, preferably 2.0 to 8.0 μm, preferably 4.0 to 8.0 μm, preferably 4.0 to 6.0 μm), the first metal layer has a thickness of 1000 nm or less, and preferably the current collector further comprises a second metal layer, the first metal layer and the second metal layer being on the opposite side of the polymer substrate layer, and the second metal layer alone has a thickness of 1000 nm or less. Preferably, the thickness of the first metal layer, and the second metal layer, if present, each alone is 50 nm to 1000 nm, preferably 100 nm to 1000 nm, preferably 100 nm to 800 nm, preferably 150 nm to 700 nm. The first metal layer, and if present the second metal layer, suitably each independently exhibit an isotropic thermal expansion in air at 200° C. of greater than 0% and less than or equal to 1.0%, preferably 0.25% to 0.75%, preferably 0.3% to 0.5%, and preferably the first metal layer and the second metal layer each independently comprise at least one of aluminium, copper, nickel, titanium, silver, a nickel-copper alloy, or an aluminium-zirconium alloy, preferably the first and second metal layers are selected from the same material, and preferably the first and second metal layers are both either aluminium or copper. Such a current collector preferably exhibits one or more of the following properties: (i) an adhesion strength between the metal layer and the polymeric substrate layer of at least 600 g / 25 mm, preferably at least about 700 g / 25 mm, and preferably at least about 800 g / 25 mm; (ii) 0.01 Ω sq -1 ~2.0Ωsq -1 , preferably 0.02Ωsq -1 ~2.5Ωsq -1 , preferably 0.02Ωsq -1 ~2.0Ωsq -1 , preferably 0.02Ωsq -1 ~1.5Ωsq -1 , preferably 0.05Ωsq -1 ~1.0Ωsq -1 Sheet resistance of (iii) a breakdown current of less than about 30 A and / or a breakdown temperature of less than about 300° C.

[0121] Such preferred current collectors may be made by a process comprising the steps of (I) forming a biaxially oriented polymeric substrate layer, and (II) depositing a metal onto one or both surfaces of the substrate layer to form a metal layer (preferably using thermal evaporation, electron beam evaporation, or virtual cathode evaporation). Preferably, step (I) comprises, in order, the following steps: (1) extruding a layer of molten polymer and subjecting the extrudate to biaxial orientation at a temperature above the glass transition temperature(s) of the polymer, preferably the biaxial orientation is simultaneous biaxial orientation, preferably wherein orientation is accomplished such that the dimensions of the oriented film are 2 to 5 times their original dimensions in each direction of orientation; (2) A temperature above the polymer's glass transition temperature(s) but not below its melting point (T M dimensionally stabilizing the biaxially stretched film by annealing under dimensional support at a temperature less than T M -80℃~T M stabilizing the temperature within the range of -10°C, and preferably within the range of 200 to 245°C, preferably within the range of 220 to 240°C; (3) subjecting the annealed biaxially stretched film to a dimensional relaxation, preferably a simultaneous dimensional relaxation, in both the transverse and machine directions, the extent of relaxation being 0.5-5.0%, preferably 1.0-4.0%, preferably 1.0-3.0%, preferably 1.0-2.0% in each of the transverse and machine directions, preferably the extent of relaxation in the machine and transverse directions is the same, preferably the extent of relaxation is the same in the machine and transverse directions, preferably the temperature of the relaxation step is equal to or lower than the temperature of the preceding annealing step, preferably 200°C-240°C, preferably 210°C to 230°C, preferably 215°C-230°C; (4) optionally a second relaxation step carried out at a lower temperature than the preceding relaxation step, preferably at least 5° C. lower, and preferably in the range of 195° C. to 230° C., preferably 195° C. to 220° C.; (5) optionally subjecting the exposed surface of the polymeric substrate layer to a surface modification treatment, which treatment step is performed after step (I) and before step (II), preferably the treatment comprises subjecting the exposed surface of the polymeric substrate layer to a plasma treatment, preferably a corona discharge; Includes.

[0122] It is to be understood that the term "metal" of the metal layer of the preferred current collector is used in a context separate and independent of the use of the term "metal" in the context of electrodes and batteries in the remainder of this disclosure. In particular, the identity of the metal layer within the current collector is independent of the identity of the metal ion in the electrode and the identity of the metal-ion battery (i.e., whether the metal-ion battery is a lithium-ion battery or a sodium-ion battery, etc.).

[0123] The preferences and elements discussed in relation to the first to third aspects apply equally to the fourth aspect.

[0124] According to a fifth aspect of the present invention, there is provided an assembly comprising a separator and an electrode, the electrode being as described in the first aspect or obtained from the method of the third aspect.

[0125] Any suitable separator may be used.

[0126] Preferred separators are disclosed, for example, in WO-2019 / 186173-A1, WO-2021 / 064359-A1, and UK Application No. 2110926.9, the disclosures of which are incorporated herein by reference. In particular, the separator may be a copolyester film comprising a copolyester comprising repeat units derived from a diol, a dicarboxylic acid, and a poly(alkylene oxide), the copolyester film further comprising a first metal ion-containing component selected from a conductive ceramic particulate material, and the film may further comprise additional metal ions from one or more sources other than the conductive ceramic particulate material.

[0127] Such a preferred separator may be made by a process that includes producing a copolyester film, the process comprising: (i) reacting the diol with the dicarboxylic acid or its ester (preferably a lower alkyl (C 1-4 ) ester, preferably a dimethyl ester) to form a bis(hydroxyalkyl) ester of the dicarboxylic acid; (ii) polymerizing the bis(hydroxyalkyl) ester of the dicarboxylic acid in a polycondensation reaction in the presence of a poly(alkylene oxide) to form a copolyester; (iii) introducing the first metal ion-containing component selected from an electrically conductive ceramic particulate material during synthesis of the copolyester of steps (i) and / or (ii) and / or during a subsequent separate compounding or mixing step to form a copolyester composition, and optionally introducing the additional metal ions from one or more sources other than the electrically conductive ceramic particulate material; (iv) forming a copolyester film from the copolyester composition, preferably by melt extruding the composition or by solvent casting a dispersion or solution comprising the copolyester composition. Includes.

[0128] The separator may be synthesized according to the techniques disclosed in UK Application No. 2110926.9, the disclosure of which is incorporated herein by reference. In particular, the film-forming copolyester composition may be cast onto a supporting base which is itself a component of the battery, in particular the electrode as described herein, i.e. the cast film is formed in situ during battery manufacture. This method of manufacture is particularly useful for solvent casting methods, but is not limited thereto, and may also be used for extrusion methods of film formation. Thus, in this embodiment, the separator of the battery is formed in situ during battery manufacture by casting the copolyester film onto the electrode. In that case, the composite structure of the electrode and the cast copolyester film is then subjected to subsequent processing to manufacture the battery.

[0129] Advantageously, when this is the case, it has been found that a continuous coating on the electrodes of the present invention can be achieved, ultimately leading to effective interfacial compatibility and contact between the separator and the electrode during use. It has been found that the contact between the separator and the electrode is not only excellent immediately after the separator is placed in the separator, but also remains excellent after use.

[0130] When conventional electrodes are used, problems occur in coating the copolyester film on the electrodes, resulting in a discontinuous coating, which in turn leads to poor interfacial compatibility and poor contact between the separator and the electrodes.

[0131] The preferences and elements discussed in relation to the first to fourth aspects apply equally to the fifth aspect.

[0132] According to a sixth aspect, there is provided a metal-ion battery (particularly a lithium-ion battery) comprising an anode, a cathode, a separator, an anode current collector and a cathode current collector, such that the layer sequence is anode current collector / anode / separator / cathode / cathode current collector, and at least one of the anode and cathode is an electrode as described herein.

[0133] Preferably, the metal-ion battery is a solid-state battery (also referred to herein as a dry cell battery). Alternatively, the metal-ion battery further comprises a liquid or gel electrolyte, which is usually referred to in the art as a wet cell battery. It is understood by those skilled in the art that the metal-ion battery is a rechargeable battery.

[0134] Any suitable anode, anode current collector, separator, cathode, cathode current collector, and electrolyte may be used as conventional in the art and as described herein.

[0135] When the metal ion battery is a solid-state battery, preferably at least one of the anode and cathode is an electrode as described herein, and the binder material comprises a copolyester comprising repeat units derived from a diol, a dicarboxylic acid, and a poly(alkylene oxide), and the binder material further comprises a first metal ion-containing component selected from a conductive ceramic particulate material, and further comprises additional metal ions from one or more sources other than the conductive ceramic particulate material.

[0136] When the metal ion battery is a wet cell battery, in one embodiment, at least one of the anode and the cathode is an electrode as described herein, and the binder material comprises a copolyester comprising repeat units derived from a diol, a dicarboxylic acid, and a poly(alkylene oxide), and the binder material does not include a first metal ion-containing component selected from a conductive ceramic particle material, and additional metal ions from one or more sources other than the conductive ceramic particle material. In this embodiment, it should be understood that the electrode does not include metal ions prior to assembly of the wet cell battery. However, during use and operation of the wet cell battery, the metal ions present in the electrolyte are mobile and enable the required conductivity. Thus, during use and operation of the wet cell battery, the metal ions saturate the electrode. In other words, during use and operation of the wet cell battery, the electrode further includes metal ions.

[0137] The preferences and elements discussed in relation to the first to fifth aspects apply equally to the sixth aspect.

[0138] According to a seventh aspect, there is provided the use of an electrode as described herein as an electrode in a battery, preferably in a metal ion battery, preferably in a lithium ion battery.

[0139] The preferences and elements discussed in relation to the first to sixth aspects apply equally to the seventh aspect.

[0140] According to an eighth aspect of the present invention, there is provided a method for manufacturing a metal-ion battery comprising an electrode as described herein, the method comprising: (a) providing an electrode as described herein; (b) assembling a metal ion battery, the battery including an anode, a cathode, a separator, an anode current collector, and a cathode current collector, such that the layer sequence is anode current collector / anode / separator / cathode / cathode current collector, and at least one of the anode and cathode is an electrode described herein; Includes.

[0141] The preferences and elements discussed in relation to the first to seventh aspects apply equally to the eighth aspect.

[0142] Characteristic measurements The following test methods were used to characterize the properties of the copolyesters, electrodes, and batteries described herein.

[0143] (i) Glass transition temperature (T g ), crystal temperature (T c ), and crystalline melting point (T m ) These thermal parameters were measured by Differential Scanning Calorimetry (DSC) using a PerkinElmer HyperDSC8500. Unless otherwise stated, measurements were performed according to the following standard test method, as described in ASTM E1356-98. Samples were kept under a dry nitrogen atmosphere for the duration of the scan. Flow rate 20 ml min -1 and Al pans were used. The samples (5 mg) were first heated at 20 °C min -1 The samples were heated from 20 to 350 °C at 100 °C. After being held isothermal at 350 °C for 2 min, the samples were heated at 20 °C min -1 The sample was then cooled to 20 °C at 20 °C min -1 The sample was then reheated to 350°C (second heating scan). g and T M The values ​​of T were obtained from the second heating scan. As is well known, the glass transition temperature of a polymer is the temperature at which the polymer changes from a glassy, ​​brittle state to a plastic, rubbery state. As explained in ASTM E1356-98, T g The value of was determined as the extrapolated onset temperature of the glass transition observed in the DSC scan (heat flow (W / g) versus temperature (°C)). g value, i.e., T of one of the soft segments g value and one of the hard segments T g It should be understood that the T c and T m The value of was determined from the DSC scan as the peak exotherm or endotherm of the transition.

[0144] (ii) Melt Viscosity As used herein, the term "melt viscosity" refers to the complex viscosity of a polymer measured at a specific melt temperature and a specific frequency. Complex viscosity was measured by rotational rheology testing using a TA Instruments DHR-1 according to the following test method: Polymer samples (2.5 g) were dried at 140°C for 16 hours under dynamic vacuum. The samples were then held between 2 x 25 mm diameter parallel plates and heated to the required temperature under a nitrogen atmosphere. Analysis of the complex viscosity of polymers was performed by the temperature ramp method, where the samples were subjected to constant strain (5%) and angular frequency (10 rad s -1 ) at 4℃ for 30 min. -1 was heated at a rate of

[0145] (iii) Bulk resistance and transmembrane ionic conductivity of preferred separators (dry cell setup (solid state)) The transmembrane ionic conductivity of the film samples in the absence of additional electrolyte, i.e., in a dry cell setup (solid state), was measured by electrochemical impedance spectroscopy (EIS). Dry coin cells of 12 mm diameter were constructed. Symmetric Al / Al dry coin cells with 1×1 mm spacers were constructed in an argon glove box at a dew point of <40° C. AC impedance spectra were acquired using an AutoLab unit under open circuit voltage (OCV) at the operating temperature of the battery (within the range of about 25° C. and about 75° C., and at ambient temperature (25° C.) unless otherwise specified) at 100 mHz to 1 MHz AC frequency range following a perturbation voltage of 10 mV. Nyquist impedance plots were generated and the x-axis intercepts were used to calculate the resistance (in ohms) of the coin cell component resistance R1 and the bulk resistance R2 of the separator (it should be understood that the separator has the relatively higher resistance value of the two values ​​generated from the Nyquist plot). The transmembrane ionic conductivity (σ) of the film separator was calculated from the bulk resistance R2 using the following equation:

number

[0146] (iv) Molecular weight (M N ) GPC measurements were performed on a Malvern / Viscotek TDA 301 using an Agilent PL HFIP gel guard column and a 2 × 30 cm PL HFIP gel column. As eluent, a HFIP solution containing 25 mM NaTFAc was used, with a nominal flow rate of 0.8 mL min -1 All experiments were performed at 40°C using a refractive index detector. Molecular weights were referenced to polymethylmethacrylate calibrators. Data acquisition and subsequent data analysis were performed using Omnisec software. Samples were 2 mg mL -1 The polymer was prepared at a concentration of 0.01 mg / mL, and 20 mg of the sample was dissolved in 10 mL of elution solution. These solutions were stirred at room temperature for 24 h and then heated at 40 °C for 30 min to completely dissolve the polymer. Each sample was filtered through a 0.45 μm polytetrafluoroethylene membrane before injection. Using such measurements, the M W M W Value and M N Once the value is known, the PDI can be determined.

[0147] (v) the level of poly(alkylene oxide) in the copolyester 1H NMR spectroscopy was used to determine the levels of poly(alkylene oxide) in the copolyester using an ECS400 spectrometer at 80 °C, based on the residual solvent (d2-TCE (1,1,2,2-tetrachloroethane)) resonance.

[0148] (vi) Expansion of the biaxially oriented polymer layer (of the preferred current collector) A sample of the biaxially oriented polymer layer of the preferred current collector having dimensions of 5 mm x 8 mm was subjected to thermomechanical analysis using a thermomechanical analyzer (TMA Q400 by TA Instruments Inc.). The longer dimension of the sample (i.e., the 8 mm dimension) corresponds to the direction in which the sample was being tested for expansion. The sample was mounted in the instrument and subjected to a strain of 1 N / mm in either the machine direction (MD) or the transverse direction (TD). 2 and a temperature ramp rate of 10°C / min from 32°C to 220°C. Thermal expansion in air at a temperature of 200°C was measured. Thermal expansion in air at 200°C is defined as the % change in the dimension of the film in a given direction (i.e., MD or TD) and was calculated as (L1-L0) / L0x100, where L0 is the dimension at 32°C and L1 is the dimension at 200°C. As one skilled in the art would understand, a negative thermal expansion indicates thermal contraction.

[0149] (vii) Sheet resistance (of the preferred current collector) The sheet resistance of the conductive layer of the preferred current collector was measured using a linear four-point probe (Jandel model RM2) in accordance with ASTM F390-98(2003).

[0150] (viii) Breakdown current and temperature at breakdown (of the preferred current collector) A current collector sample having dimensions of 50 mm x 10 mm was held at each end between a pair of conductive clamps. The sample was clamped to within 10 mm of each end of the sample. 2 The specimen was then tightened so that the wire was held within the clamp. A current was passed through the specimen at a ramp rate of 2 A / min until failure was observed. The temperature profile of the specimen was monitored throughout the test using a thermal imaging camera to determine the temperature at failure.

[0151] (ix) Adhesive strength (of the preferred current collector) The adhesion strength of the metallized polymer substrate to 25 μm thick EAA (ethylene acrylic acid film) (commercially available as Vistafix (TP) from UCB Sidac Division) was evaluated as follows: A sample of current collector and a sample of EAA film were positioned together such that the outer surface of the metallized polymer substrate layer was in contact with the surface of the EAA film. The samples were heat fused using a Sentinel Model 12 (Packaging Industries Group Inc) machine under the following conditions: 105° C. (upper jaw) and 25° C. (lower jaw), 50 psi pressure for 10 seconds. The fused samples were cut into 25 mm wide strips and the adhesion strength was measured using an Instron model 4464. The jaws were set 50 mm apart. The upper jaw held the EAA portion of the fused sample and rose at a rate of 300 mm / min, while the lower jaw held the current collector portion of the fused sample and remained stationary. The average peel force was measured and reported as the average of five results. The adhesive failure surface was also observed. If the adhesive strength between the metal layer and the polymeric substrate layer is lower than the adhesive strength between the metal layer and the EEA film (about 800 g / 25 mm), the test sample peels off along the interface of the metal layer and the polymeric substrate layer. In this case, the average peel force represents the adhesive strength between the metal layer and the polymeric substrate layer. If the adhesive strength between the metal layer and the polymeric substrate layer is higher than the adhesive strength between the metal layer and the EEA film (800 g / 25 mm), the test sample peels off along the interface of the metal layer and the EEA film. A further failure surface is a coherent failure within the metallized layer itself, which also indicates that the adhesive strength between the metal layer and the polymeric substrate layer is greater than the force required to achieve a coherent failure (thus, typically, the adhesive strength between the metal layer and the polymeric substrate layer is greater than about 800 g / 25 mm).

[0152] The invention will now be further described with reference to the following non-limiting examples. [Brief description of the drawings]

[0153] [Figure 1] FIG. 1 is a diagram showing the results of Comparative Example 1. [Diagram 2] FIG. 1 shows the results of Example 1. [Diagram 3] 13 is a graph showing electrode potential as a function of specific capacitance in experiment 2. EXAMPLES

[0154] In the following description, "LICGC" refers to a lithium ion conductive glass-ceramic powder commercially available from Ohara under the trade name LICGC™ PW-01, and "PEG3350" refers to a PEG having a number average molecular weight (M N ) refers to polyethylene glycol having the formula:

[0155] Experiment 1 In the examples, an assembly was prepared that included an electrode, a current collector, and a separator, with the layer order being separator / electrode / current collector.

[0156] Specifically, an aluminum current collector foil was obtained. An electrode was prepared and cast onto the surface of the current collector as detailed in the specific examples below. A separator film comprising a copolyester, LICGC, and LiCF3SO3 was then prepared and cast onto the opposing surface of the electrode as follows.

[0157] A copolyester was prepared using bis(2-hydroxyethyl)isophthalic acid (BHEI) and polyethylene glycol (PEG 3350). PEG 3350 was present at a level of 50% by weight of the copolyester. The copolyester was prepared by reacting 49.82 g of BHEI with 50.18 kg of PEG 3350 with the addition of an antioxidant (Irganox® 1010, 2.95 g). Polycondensation was achieved at approximately 280-290°C using antimony trioxide catalyst (0.20 g) and the pressure above the melt was reduced to less than 5 mm Hg. The viscosity of the batch increased as the polycondensation reaction proceeded and when the desired viscosity was reached, the polycondensation reaction was stopped by returning the pressure in the vessel to atmospheric pressure. The copolyester was then extruded into a lacy shape, cast into a water bath and dried. Solvent cast copolyester films were made by dissolving 0.4 g of the copolyester in 5 mL of NMP containing 0.1 g of LiCF3SO3 and 0.5 g of LICGC. The components were dispersed in NMP in a beaker and mixed thoroughly at 25°C for 12 hours to provide the copolyester composition. Separator films were made by solvent casting the copolyester composition onto the surface of an electrode, heated and dried at 60°C for 24 hours, and then vacuum dried at 60°C for an additional 24 hours to provide a separator film with a thickness of 82 μm. The uniformity of coverage of the separator film on the electrode was evaluated.

[0158] Comparative Example 1 The electrodes were obtained from a composition made by mixing lithium titanate oxide (LTO) as the active material, polyvinylidene fluoride (PVDF), Li salt, and LiCGC.

[0159] The composition was cast onto an aluminum current collector foil, and the resulting product was then dried, thereby forming an electrode.

[0160] The separator material was then cast onto the electrode as described above. The results are shown in Figure 1 and show that the separator did not achieve a continuous film coverage on the electrode surface. Instead, only partial coverage was observed, and the interfacial compatibility and contact between the electrode and the separator was poor.

[0161] Example 1 The electrodes were obtained from a composition made by mixing lithium titanate oxide (LTO) with the copolyester composition described above for the separator material (i.e., a composition including the copolyester, LiCF3SO3, and LICGC dispersed and thoroughly mixed in NMP).

[0162] The composition was cast onto an aluminum foil and the resulting product was then dried, thereby obtaining an electrode.

[0163] The separator material was then cast onto the electrode as described above. The results are shown in Figure 2 and show that the separator achieved a continuous and uniform film coverage over the entire electrode surface. Interfacial compatibility and contact between the electrode and separator were excellent.

[0164] Experiment 2 A solid-state cell battery was prepared using the separator, cathode, and cathode current collector of Example 2. Lithium foil was used as the anode and was in contact with the separator surface such that the layer sequence was lithium foil anode / separator / cathode / aluminum foil cathode current collector.

[0165] The battery characteristics were evaluated. The bulk resistance was 5.6 kΩ. Figure 3 presents the electrode potential as a function of specific capacity. As shown in Figure 3, the battery could be effectively charged and discharged.

Claims

1. 1. An electrode comprising an active material and a binder material, wherein the binder material comprises a thermoplastic copolyester comprising repeating units derived from a diol, a dicarboxylic acid, and a poly(alkylene oxide), the binder material further comprising a first metal ion-containing component selected from a conductive ceramic particulate material, the first metal being lithium, the lithium ion-containing conductive ceramic particulate material being selected from a NASICON-type ceramic particulate material, a LISICON-type ceramic particulate material, a perovskite-type oxide ceramic particulate material, a garnet-type oxide ceramic particulate material, and a lithium phosphorus oxynitride (LIPON)-type ceramic particulate material, and the binder material may further comprise additional metal ions from one or more sources other than the conductive ceramic particulate material.

2. 10. The electrode of claim 1, wherein the copolyester comprises a semi-crystalline segment derived from a dicarboxylic acid and an aliphatic diol and an amorphous segment derived from a poly(alkylene oxide).

3. 2. The electrode of claim 1, wherein the poly(alkylene oxide) comprises 0.1 to 80 weight percent of the total weight of the copolyester.

4. The diol is C 2 , C 3 , or C 4 10. The electrode of claim 1, wherein the diol is selected from aliphatic diols.

5. 2. The electrode of claim 1, wherein the dicarboxylic acid is an aromatic dicarboxylic acid selected from isophthalic acid, naphthalene dicarboxylic acid, and terephthalic acid.

6. 2. The electrode of claim 1, wherein the poly(alkylene oxide) is selected from polyethylene glycol (PEG), polypropylene glycol (PPG), and poly(tetramethylene oxide) glycol (PTMO).

7. 2. The electrode of claim 1, wherein the poly(alkylene oxide) has a number average molecular weight of 200 to 20,000 g / mol.

8. The electrode of claim 1, wherein the binder material comprises the additional metal ions.

9. 10. The electrode of claim 1, wherein the additional metal ion is in the form of a second metal ion component selected from metal salts.

10. The electrode of claim 1 , wherein the metal of the first metal ion-containing component is the same as the metal of the additional metal ion.

11. The electrode of claim 1, wherein the metal of the additional metal ion is selected from lithium, sodium, potassium, calcium, magnesium, and aluminum.

12. An electrode as described in claim 1, wherein the lithium ion-containing conductive ceramic particle material is selected from NASICON-type ceramic particle materials which are lithium ion-containing conductive glass ceramic particle materials.

13. The lithium ion-containing conductive ceramic particulate material, General formula LiM y (P.O. 4 ) 3 wherein M represents a polyvalent metal ion such as one or more of Al, Si, Ti, Zr, Ge, Sn, and Hf; General formula Li 1+x M x Ti 2-x (P.O. 4 ) 3 wherein M represents a trivalent cation selected from one or more of Al, Sc, Y, and La; General formula Li 1+x Al x Ge 2-x (P.O. 4 ) 3 NASICON type materials having Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 and the crystalline phase of Li 2 O-Al 2 O 3 -SiO 2 -P 2 O 5 -TiO 2 and a material having a composition of Li 1+x+y Al x (Ti, Ge) 2-x Si y P 3-y O 12 The main crystalline phase of Li 2 O-Al 2 O 3 -SiO 2 -P 2 O 5 -TiO 2 -GeO 2 and a material having a composition of General formula Li 2+2x Zn 1-x GeO 4 and optionally other elements are Li 2+2x Zn 1-x Ge 4 O 16 , Li 14 ZnGe 4 O 16 , Li (3+x) Ge x V (1-x) O 4 , Li (4-x) Si (1-x) P x O 4 the LISICON-type material, which may replace the Li, Zn, and / or Ge, such as Li (4-x) Ge (1-x) P x S 4 Li 10 GeP 2 S 12 Thiolicon-type materials such as Li 3x La (2 / 3)-x TiO 3 and Li 3x La 1 / 3-x TaO 3 Perovskite oxide materials such as (i) Li 5 La 3 M 2 O 12 (wherein M represents Nb and / or Ta), (ii) Li 6 ALa 2 M 2 O 12 (wherein A represents Ca, Sr, and / or Ba, and M represents Nb or Ta), or (iii) Li 6.5 La 2.5 Ba 0.5 ZrTaO 12 General formula Li 7-3y-x La 3 Zr 2-x M1 y M2 x O 12 wherein M1 represents trivalent cations such as Al and Ga, M2 represents pentavalent cations such as Nb and Ta, and x≧0 and y≦2; and Li 2 P.O. 2 N, etc., with the general formula Li x P.O. y N z LIPON type material having The electrode of claim 1 , wherein the electrode is selected from:

14. 10. The electrode of claim 1, wherein the amount of said metal ion-containing conductive ceramic particulate material is present in said binder material in the range of 0.1% to 60% by weight of the total weight of said binder material.

15. The additional metal ion is (i) aromatic carboxylic acids, (ii) aliphatic carboxylic acids, including aliphatic dicarboxylic acids (iii) carbonic acid, (iv) phenolic acids, (v) a mineral acid, and (vi) Boric acid 10. The electrode of claim 1, in the form of a metal salt selected from the salts of

16. 10. The electrode of claim 1, wherein the additional metal ions are in the form of a metal salt of an organic acid.

17. 16. The electrode of claim 15, wherein the additional metal ion is in the form of a metal salt selected from the alkoxylate ester of the acid and / or the alkoxylate ester is derived from the aliphatic diol.

18. The additional metal ion is a lithium ion, and bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium thiocyanate (LiSCN), lithium hexafluoroarsenate (LiAsF 6 ), lithium trifluoromethanesulfonate (LiCF 3 SO 3 ), lithium bromide (LiBr), lithium iodide (LiI), lithium bis(trifluoromethanesulfonimide) (LiN(CF 3 SO 2 ) 2 ), lithium tris(trifluoromethylsulfonyl)methide (LiC(CF 3 SO 2 ) 3 ), lithium orthosilicate, lithium trifluoroacetate (LiCF 3 CO 2 ), lithium bis(fluorosulfite)amide (LiN(FO 2 S) 2 ), dilithium terephthalate (DLTA), dilithium isophthalate, lithium glycolate, lithium benzoate, lithium acetate, lithium carbonate, lithium perchlorate, lithium orthosilicate, lithium phosphate, lithium salicylate, lithium succinate, lithium bis(oxalato)borate, and dilithium bishydroxyethyl terephthalate (DL-BHET).

19. The additional metal ion is a lithium ion, and examples thereof include dilithium terephthalate (DLTA), dilithium isophthalate, dilithium bishydroxyethyl terephthalate (DL-BHET), and LiCF 3 SO 3 10. The electrode of claim 1, in the form of a lithium salt selected from:

20. The additional metal ion is sodium ion, and sodium nitrate (NaNO 3 ), sodium perchlorate (NaClO 4 ), sodium tetrafluoroborate (NaBF 4 ), sodium hexafluorophosphate (NaPF 6 ), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI), sodium bis(trifluoromethane)sulfonimide (Na[N(CF 3 SO 2 ) 2 ]), sodium hexafluoroarsenate(V) (NaAsF 6 10. The electrode of claim 1, wherein the electrode is in the form of a sodium salt selected from sodium bis(oxalatoborate) ("NaBOB"), sodium halide (NaX) (where X = Cl, Br, or I), sodium thiocyanate (NaSCN), sodium pentacyanopropenide (NaPCPI), sodium tetracyanopyrrolate (NaTCP), and sodium tricyanoimidazolate (NaTIM).

21. 2. The electrode of claim 1, wherein the additional metal ions are present in and held within the polymer matrix of the binder material by the interaction between the metal cations and negatively charged oxygen atoms of the copolyester.

22. 2. The electrode of claim 1, wherein the additional metal ions are in the form of a metal salt and are held within the polymer matrix of the copolyester by the interaction between the metal cation and the anion of the metal salt that is not covalently bonded to the copolyester.

23. 10. The electrode of claim 1, wherein the amount of the additional metal ions in the film is effective to provide a metal:O molar ratio of from 5:1 to 1:50, where the number of O atoms in this ratio is defined as the number of O atoms in the poly(alkylene oxide) residue and the number of metal atoms in this ratio is defined as the number of metal atoms provided by the additional metal ions.

24. 2. The electrode of claim 1, wherein the additional metal ions are in the form of a second metal ion component present in the binder material in an amount of 0.1 wt. % to 40 wt. %, preferably 1 wt. % to 10 wt. % of the total weight of the binder material.

25. 2. The electrode of claim 1, wherein the binder material comprises an inorganic particulate filler selected from alumina, titania, zirconia, zinc oxide, semi-metallic oxides such as talc and silica, calcined china clay, alkali metal salts such as carbonates and sulfates of calcium and barium, and non-conductive ceramic particulate materials, and the inorganic particulate filler is a separate entity from the first and second metal ion-containing components and does not contain the metal ions of the first or second metal ion-containing components.

26. 10. The electrode of claim 1, wherein the binder material is present in an amount of 0.1 to 25 weight percent of the total weight of the electrode.

27. 10. The electrode of claim 1, wherein the electrode is an anode and the active material is selected from graphite and / or lithium titanate (LTO).

28. 10. The electrode of claim 1, wherein the electrode is a cathode and the active material is selected from lithium or mixed oxides of lithium and other metal(s).

29. 10. The electrode of claim 1, wherein the active material is present in an amount of 75 to 99.1 wt. % of the total weight of the electrode.

30. The electrode of claim 1 which is a film.

31. 10. The electrode of claim 1, cast onto a supporting base, preferably said supporting base being a current collector or separator.

32. 1. Use of a binder material in a composition for forming an electrode, the binder material comprising a thermoplastic copolyester comprising repeating units derived from a diol, a dicarboxylic acid, and a poly(alkylene oxide), the binder material further comprising a first metal ion-containing component selected from a conductive ceramic particulate material, the first metal being lithium, the lithium ion-containing conductive ceramic particulate material being selected from a NASICON-type ceramic particulate material, a LISICON-type ceramic particulate material, a perovskite-type oxide ceramic particulate material, a garnet-type oxide ceramic particulate material, and a lithium phosphorus oxynitride (LIPON)-type ceramic particulate material, and the binder material may further comprise additional metal ions from one or more sources other than the conductive ceramic particulate material.

33. 33. Use of a binder material according to claim 32, wherein the binder material is as described in claim 2.

34. 10. A method for manufacturing the electrode of claim 1, comprising: (i) reacting the diol with the dicarboxylic acid or ester thereof to form a bis(hydroxyalkyl) ester of the dicarboxylic acid; (ii) polymerizing the bis(hydroxyalkyl) ester of the dicarboxylic acid in a polycondensation reaction in the presence of a poly(alkylene oxide) to form a thermoplastic copolyester; (iii) optionally introducing, during synthesis of the copolyester of step (i) and / or (ii) and / or subsequent combining or mixing with a separate copolyester, the first metal ion-containing component selected from a conductive ceramic particulate material, and optionally introducing the additional metal ions from one or more sources other than the conductive ceramic particulate material, wherein the first metal ion-containing component is a lithium ion-containing conductive ceramic particulate material selected from a NASICON-type ceramic particulate material, a LISICON-type ceramic particulate material, a perovskite-type oxide ceramic particulate material, a garnet-type oxide ceramic particulate material, and a lithium phosphorus oxynitride (LIPON)-type ceramic particulate material; (iv) providing the copolyester product from step (ii) or (iii) as a binder material; (v) mixing the active material with the binder material to form a composition; (Vi) forming an electrode from the composition, preferably by solvent casting a dispersion or solution comprising the composition; The method comprising:

35. 35. The method of claim 34, wherein the electrode composition is disposed on a supporting base that is itself a component of a solid-state battery.

36. 35. An electrode obtained by the method of claim 34.

37. An assembly comprising a current collector and an electrode, wherein the electrode is the electrode of claim 1.

38. An assembly comprising a separator and an electrode, wherein the electrode is the electrode of claim 1.

39. 38. Use of an electrode according to claim 1 or of an assembly according to claim 37 in a metal ion battery.

40. 10. A metal-ion battery comprising an anode, a cathode, a separator, an anode current collector, and a cathode current collector, such that the layer order is anode current collector / anode / separator / cathode / cathode current collector, and at least one of the anode and the cathode is the electrode of claim 1.

41. 41. The metal-ion battery of claim 40, wherein the metal-ion battery is a solid-state battery.

42. 41. The metal-ion battery of claim 40, wherein the metal of the metal-ion battery is lithium.

43. 41. The metal-ion battery of claim 40, wherein the separator is a copolyester film comprising a copolyester comprising repeating units derived from a diol, a dicarboxylic acid, and a poly(alkylene oxide), the copolyester film further comprising a first metal ion-containing component selected from a conductive ceramic particulate material, the first metal being lithium, the lithium ion-containing conductive ceramic particulate material being selected from a NASICON-type ceramic particulate material, a LISICON-type ceramic particulate material, a perovskite-type oxide ceramic particulate material, a garnet-type oxide ceramic particulate material, and a lithium phosphorus oxynitride (LIPON)-type ceramic particulate material, and the film may further comprise additional metal ions from one or more sources other than the conductive ceramic particulate material.

44. the anode current collector and / or the cathode current collector is independently selected from current collectors comprising a biaxially oriented polyester substrate layer and a first metal layer on a side surface of the polyester substrate layer, the polyester substrate layer exhibiting positive thermal expansion in air at 200°C in each of the transverse direction (TD) and the machine direction (MD), the polyester substrate layer having a thickness of 12 μm or less, the first metal layer having a thickness of 50 to 1000 nm, and / or the current collector further comprising a second metal layer having a thickness of 50 to 1000 nm; 41. The metal-ion battery of claim 40, wherein the first metal layer and the second metal layer are on opposite sides of the polyester substrate layer, and preferably the first metal layer, and, if present, the second metal layer, each independently comprise at least one of aluminum, copper, nickel, titanium, silver, a nickel-copper alloy, or an aluminum-zirconium alloy; and / or the first and second metal layers are selected from the same material, preferably both are either aluminum or copper.

45. 41. A method of manufacturing the metal ion battery of claim 40 comprising the electrode of claim 1, comprising: (a) providing or obtaining an electrode according to claim 1; (b) assembling a lithium ion rechargeable battery, the battery comprising an anode, a cathode, a separator, an anode current collector, and a cathode current collector, wherein at least one of the anode and the cathode is the electrode obtained from step (a); The method comprising:

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