Composition comprising lithium lanthanum zirconium oxide

Abstract

The invention relates to a composition comprising a) particles comprising lithium lanthanum zirconium oxide, and b) a polymer comprising a polyether segment, wherein the polymer comprises one alkyl ether end group and one carboxylic acid end group, wherein the carboxylic acid end group is linked to the polyether segment via a linking segment comprising a carboxylic acid ester group.

Description

[0001] Composition comprising lithium lanthanum zirconium oxide

[0002] The invention relates to a composition comprising particles comprising lithium lanthanum zirconium oxide and a polymer, to the use of the composition for preparing a battery, to a solid electrolyte battery, to the use of a polymer comprising a polyether segment for dispersing solid particles comprising lithium lanthanum zirconium oxide, and to process of preparing an ion- conductive membrane or separator for an electrochemical device.

[0003] Rechargeable lithium-ion batteries typically use liquid electrolytes to separate the positive and negative electrodes. Several drawbacks are associated with liquid electrolytes, such as flammability of liquid electrolytes, gas formation at high voltage, chemical incompatibility with lithium metal electrodes, and poor cycling performance. Some of these drawbacks are believed to be avoided with the use of solid-state electrolytes. Moreover, solid-state batteries are potentially safer and may realize higher energy densities in batteries.

[0004] Solid-state electrolytes candidate materials include ceramics such as lithium orthosilicate, glass, sulfides and RbAg^s. Other solid electrolytes include lithium aluminum germanium phosphate, lithium aluminum titanium phosphate, lithium lanthanum titanium oxide, and lithium lanthanum zirconium oxide.

[0005] International patent application WO 2018 / 027200 A1 describes a battery or components thereof comprising lithium lanthanum zirconium oxide particles as solid electrolyte. The use of various dispersants in combination with such particles is described, for example phosphate esters, fish oil, and acrylic polymers.

[0006] US 2022 / 0021024 relates to solid-state separators which are useful in lithium ion-conducting electrolytes in electrochemical cells and devices. Various lithium-containing solid electrolytes are described, including lithium lanthanum zirconium oxide particles. As dispersants for the solid electrolytes are mentioned, among others, phosphate esters, fish oil, surfactants, polyvinyl pyridine, and polyalkylene amine.

[0007] There is an ongoing need for dispersants for lithium lanthanum zirconium oxide particles, which provide a low viscosity of the dispersion, and a low particle size of the solid particles. Moreover, for use in electrochemical cells the dispersants should have a low ash content. The resulting electrochemical cells should exhibit a good electrochemical stability. In view of the above, the invention provides a composition comprising a) particles comprising lithium lanthanum zirconium oxide, and b) a polymer comprising a polyether segment, wherein the polymer comprises one alkyl ether end group and one carboxylic acid end group, wherein the carboxylic acid end group is linked to the polyether segment via a linking segment comprising a carboxylic acid ester group.

[0008] The composition of the invention has a low viscosity and provides for well dispersed particles of lithium lanthanum zirconium oxide having as low particle size. The polymer has a low ash content. When the composition is used for the production of electrochemical cells, such electrochemical cells have a good electrochemical stability.

[0009] As mentioned above, the composition of the invention comprises a polymer comprising a polyether segment, wherein the polymer comprises one alkyl ether end group and one carboxylic acid end group, wherein the carboxylic acid end group is linked to the polyether segment via a linking segment comprising a carboxylic acid ester group.

[0010] The polymer suitably is a linear polymer or essentially linear polymer having a polymer main chain without or with at most one polymeric branch. Preferably, the polymer has no polymeric branches.

[0011] The polymer has one alkyl ether end group. Generally, the alkyl ether end group comprise alkyl groups having 1 to 32 carbon atoms, preferably 1 to 24 carbon atoms. When the alkyl ether end groups contain more than 32 carbon atoms, the stability of the dispersions of lithium lanthanum zirconium oxide particles may deteriorate.

[0012] The polymer comprises a polyether segment. In an exemplary embodiment, the polyether segment comprises polyalkylene oxide units.

[0013] Polyether segments based on polyalkylene oxide units are commercially commonly available. Examples of polyalkylene oxide units are polyethylene oxide units (PEG), polypropylene oxide units (PPO) and polybutylene oxide units (PBO). In exemplary embodiments, the polyether segment comprises at least one polyalkylene oxide unit selected from the group consisting of polyethylene oxide units, polypropylene oxide units and polybutylene oxide units.

[0014] In particular embodiments, the polyether segment comprises at least two polyalkylene oxide blocks, a first polyalkylene oxide block being different from a second polyalkylene oxide block, wherein each polyalkylene oxide block comprises one polyalkylene oxide unit selected from the group consisting of PEO, PPO and PBO. Preferably, polyether segment comprises three polyalkylene oxide blocks, wherein a second polyalkylene oxide block, which is arranged between a first polyalkylene oxide block and a third polyalkylene oxide block, is different from said first polyalkylene oxide block, and wherein the third polyalkylene oxide block is equal to the first polyalkylene oxide block. In an example, said polyether segment is a PEO / PPO / PEO triblock copolymer. An example of a PEO / PPO / PEO triblock copolymer is Pluronic P-123 supplied by BASF.

[0015] In particular embodiments, the polyether segment comprises at least two polyalkylene oxide units, which at least two polyalkylene oxide units are arranged in a random order along the polyether segment. Said polyether segment is a statistical copolymer of said at least two polyalkylene oxide units.

[0016] It is generally preferred that the polyether segment comprises polymerized units of ethylene oxide or propylene oxide, or combinations thereof.

[0017] In preferred embodiments, the polymer has a number average molecular weight in the range of 200 to 1500 g / mol. More preferably, the polymer has a number average molecular weight in the range of 300 to 1400 g / mol, most preferably in the range of 350 to 1300 g / mol. The number average molecular weight can be determined by gel permeation chromatography, using polystyrene as calibration standard and THF as eluent, according to DIN EN ISO 13885-1.

[0018] As mentioned above, the carboxylic acid end group is linked to the polyether segment via a linking segment comprising a carboxylic acid ester group. Said linking segment, which has a linking ester group, may be easily formed by a condensation or addition reaction using a dicarboxylic acid or a cyclic acid anhydride.

[0019] In a particular embodiment, the linking segment is formed by a ring opening addition reaction of a cyclic acid anhydride and a polyether segment having one hydroxyl end group per molecule. The resulting linking segment comprises an ester group and a hydrocarbyl group located between the ester group and the carboxylic acid group. A carboxylic acid end group is provided by the ring opening addition reaction of the anhydride. Said cyclic acid anhydride may be selected from the group consisting of maleic anhydride, itaconic anhydride, citraconic anhydride, succinic anhydride, substituted succinic anhydride, such as alkyl succinic anhydride or alkenyl succinic anhydride, phthalic anhydride, and glutaric anhydride. An advantage of using a cyclic acid anhydride is a desired number of the carboxylic acid end groups may easily be obtained due to a high selectivity of the addition reaction. Another advantage is that the average molecular weight and / or the polydispersity of the resulting polymer is substantially unchanged compared to the pre-polymer or polyether segment having the hydroxyl end groups. Another advantage is that no water is formed due to the addition reaction of the cyclic acid anhydride and the polyether segment having hydroxyl end groups.

[0020] The linking segment further comprises a hydrocarbyl group having 2 to 30 carbon atoms located between the ester group and the carboxylic acid group.

[0021] In an exemplary embodiment, the linking segment comprises a hydrocarbyl group located between the ester group and the carboxylic acid group, wherein the ester group and the carboxylic acid group are separated by at most 6 carbon atoms. The at most 6 carbon atoms between the ester group and the carboxylic acid group may be part of at least one of a linear, saturated, halogenated or non-halogenated alkyl group with 1 to 6 carbon atoms, a branched, saturated, halogenated or non-halogenated alkyl group, an aryl group, an alkylaryl group or arylalkyl group, an alkoxyalkyleneoxide residue or an alkoxypolyalkyleneoxide residue, wherein the alkylene unit is in each case preferably a C2-C4, more preferably an C2- and / or C3- alkylene unit.

[0022] In particular embodiments, the linking segment may comprise more than said at most 6 carbon atoms. For example any one of a branched alkyl group, an arylgroup, and an arylalkyl group may comprise additional carbon atoms additional to the 6 carbon atoms, which separate the ester group from the carboxylic acid group.

[0023] Due to the presence of carboxylic acid groups, the polymer used in the composition of the invention has an acid value. In specific embodiments, the polymer has an acid value in the range of 25 to 250 mg KOH / g. Preferably, the acid value of the polymer is at least 30 mg KOH / , and most preferably at least 35 mg KOH / g. In further preferred embodiments, the acid value of the polymer is at most 230 mg KOH / g, more preferably at most 200 mg KOH / g. An acid value within the preferred ranges leads to a particular good dispersion of lithium lanthanum zirconium oxide particles. The acid value is the KOH quantity in mg that is required for neutralizing 1 g of substance. The acid value are suitably determined by a neutralization reaction with a 0.1 N KOH in Ethanol according to DIN EN ISO 2114.

[0024] The polymer has one carboxylic acid group. This means that the majority of individual molecules has one carboxylic acid end group. However, due to impurities in raw materials and due to possible side reactions, there may be a small amount of polymer molecules having no carboxylic acid end group, as well as a small proportion of molecules having 2 carboxylic acid end groups. As a consequence, the average functionality, i.e. the average number of carboxylic acid groups end per molecule, may be in the range of 0.8 to 1 .2. If the average carboxylic acid functionality is outside this range, the quality of the dispersion of lithium lanthanum zirconium oxide particles deteriorates.

[0025] The polymer has one alkyl ether end group. This means that the majority of individual molecules has one alkyl ether end group. However, due to impurities in raw materials and due to possible side reactions, there may be a small amount of polymer molecules having no alkyl ether end group, as well as a small proportion of molecules having 2 alkyl ether end groups. As a consequence, the average functionality, i.e. the average number of alkyl ether groups per molecule, may be in the range of 0.8 to 1.2. If the average alkyl ether end group functionality is outside this range, the quality of the dispersion of lithium lanthanum zirconium oxide particles deteriorates.

[0026] In preferred embodiments, the composition of the invention is a liquid or in the form of a paste at a temperature of 20 °C. In order to render the composition liquid or paste-like, the composition preferably comprises one or more solvents or diluents which is liquid at a temperature of 20 °C. Generally, an organic solvent is selected as diluent that is capable of dissolving the polymeric or oligomeric components of the composition. The organic solvent may also comprise more than one type of organic solvent, for example a mixture of two or more types of solvents. Examples of suitable solvents include ester solvents, such as methyl acetate, ethyl acetate, butyl butyrate, y-butyrolactone, and e-caprolactone; an aromatic-based solvent such as tetralin; an ether-based solvent such as dibutyl ether or tetrahydrofuran; a ketone-based solvent such as cyclohexanone; an aromatic hydro- carbon-based solvent such as benzene, toluene, xylene, and fluorobenzene; or a carbonate-based solvent such as dimethyl carbonate (DMC), diethyl carbonate (DEC), methylethyl carbonate (MEC), ethylmethyl carbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC); an alcohol-based solvent such as ethyl alcohol and isopropyl alcohol; nitriles such as R-CN (where R is a linear, branched, or cyclic C2-C20 hydrocarbon group and may include a doublebond aromatic ring or ether bond); amides such as dimethylformamide; dioxolanes such as 1 ,3-dioxolane; or sulfolanes may be used as the organic solvent. Examples of further suitable solvents include aprotic dipolar solvents, such as dimethyl sulfoxide, dimethyl formamide or N- methyl pyrrolidone, or other solvents comprising an amide group. In the case of using water as a solvent, it may be preferred to use further include a thickener. The amount of the solvent is adjusted so as to obtain a viscosity at which a paste can be applied to a collector easily.

[0027] Generally, the solvent or diluent is present in the composition of the invention in an amount of 10 to 90 % by weight, calculated on the total weight of the composition.

[0028] In another embodiment, the composition further comprises an organic polymeric binder which is different from component b). The binder improves the adhesion between the components and any surfaces to which the composition is applied, such as a current collector, or any other component of an electrochemical device. Examples of the binder include known binders such as: fluorine-based polymers such as polyvinylidene fluoride, polyvinylidene fluoridehexafluoropropylene copolymer, and polytetrafluoroethylene; rubber-based binders such as styrene-butadiene rubber (SBR), nitril-butadiene rubber (NBR), hydrogenated nitrile-butadiene rubber (HNBR), ethylene-propylene-diene monomer rubber (EPDM), a sulfonated EPDM, and a fluorine rubber; polyethylene; polypropylene; polyvinyl alcohol; polyvinylpyrrolidone, polyacrylonitrile; carboxymethyl cellulose (CMC); starch; hydroxypropyl cellulose; regenerated cellulose; and binders based on polyacrylates, such as poly(acrylic acid) (PAA). If so desired, the binder may be used in the form of an aqueous dispersion.

[0029] A suitable use amount of the binder is 1 .0 to 50.0 parts by mass in terms of 100 parts by mass of the non-volatile material of the composition, and in particular, the used amount is preferably about 1.0 to 20.0, more preferably 1.0 to 10.0 parts by mass.

[0030] The composition further comprises particles comprising lithium lanthanum zirconium oxide.

[0031] Lithium lanthanum zirconium oxide or lithium lanthanum zirconate is a lithium-stuffed garnet material that is under investigation for its use in solid-state electrolytes in lithium-based battery technologies. Lithium lanthanum zirconium oxide has a high ionic conductivity and chemical stability against lithium metal, giving it an advantage for use as an electrolyte in solid-state batteries.

[0032] In preferred embodiments, lithium lanthanum zirconium oxide doped with aluminum is used.

[0033] Suitable lithium lanthanum zirconium oxide particles are commercially available. Examples of commercial suppliers include Materion Advance Chemicals, NEI Corporation, OHARA, Ionic material, Empower Materials, Ampeca Corp, and TOSHIMA Manufacturing. In some embodiments, the lithium lanthanum zirconium oxide particles comprise a material of the formula

[0034] LiuLavZrxMeyOz, wherein u is in the range of 4 to 8; v is in the range of 2 to 4; x is in the range of 1 to 3; y is in the range of 0 to 1 ; z is in the range of 10 to 14;

[0035] Me is a metal.

[0036] In some embodiments, the optional metal Me is a post-transition metal. The post-transiton metals are the metallic elements in the periodic table located between the transition metals and the non-metallic elements to their right. Particularly suitable metals are aluminum, gallium, indium, tallium niobium, tantalum, tin, lead, and bismuth.

[0037] Preferably, Me is aluminum.

[0038] In the composition of the invention polymer b) acts as a dispersing agent for the particles comprising lithium lanthanum zirconium oxide.

[0039] Stable dispersions are obtained when polymer b) is present in an amount of 0.5 to 20.0 % by weight, calculated on the weight of the particles comprising lithium lanthanum zirconium oxide. In preferred embodiments, polymer b) is present in an amount of 1.5 to 15.0 % by weight, more preferably 2.0 to 12.0 % by weight, calculated on the weight of the particles comprising lithium lanthanum zirconium oxide.

[0040] The size of the lithium lanthanum zirconium oxide particles in the composition of the invention is generally in the range of 100 nm to 2000 nm, preferably in the range of 200 to 1800 nm. The particle size is expressed as D50 particle size, determined by the dynamic light scattering method.

[0041] The invention also relates to the use of a polymer comprising a polyether segment, wherein the polymer comprises one alkyl ether end group and one carboxylic acid end group, wherein the carboxylic acid end group is linked to the polyether segment via a linking segment comprising a carboxylic acid ester group for dispersing solid particles comprising lithium lanthanum zirconium oxide.

[0042] In a further aspect, the invention relates to a process of dispersing particles comprising lithium lanthanum zirconium oxide in a liquid medium, wherein a dispersing agent is present, which is a polymer comprising a polyether segment, wherein the polymer comprises one alkyl ether end group and one carboxylic acid end group, wherein the carboxylic acid end group is linked to the polyether segment via a linking segment comprising a carboxylic acid ester group. In the process according to the invention, shear force is exerted to a liquid composition comprising particles comprising lithium lanthanum zirconium oxide and a polymer comprising a polyether segment, wherein the polymer comprises one alkyl ether end group and one carboxylic acid end group, wherein the carboxylic acid end group is linked to the polyether segment via a linking segment comprising a carboxylic acid ester group.

[0043] In a further aspect, the invention also relates to use of the composition according to the invention for preparing a battery comprising a solid electrolyte.

[0044] In one embodiment, the invention relates to a process of preparing an ion-conductive membrane or separator for an electrochemical device, wherein the composition according to is employed for producing the membrane or separator.

[0045] Suitably, the membrane or separator is conductive for Lithium ions and is polycrystalline.

[0046] Suitably, the process includes at least one step which includes sintering, hot isostatic pressing, sinter forging, gel casting, hot pressing sintering, spark plasma sintering, or a combination thereof.

[0047] In a typical embodiment, the process comprises the steps of providing an inorganic material comprising lithium lanthanum zirconium oxide; milling the inorganic material to form a milled inorganic material; annealing the milled inorganic material to form an annealed inorganic material; pressing the annealed inorganic material; and heating the inorganic material.

[0048] In some embodiments of the process, the milling the inorganic material to form a milled inorganic material includes milling until the inorganic material has a d50 particle size of 100 nm to 1000 nm.

[0049] In some embodiments, the annealing the milled inorganic material to form an annealed inorganic material includes heating the inorganic material. In some examples, the heating includes heating the inorganic material to at least 400, 500, 600, 700, 800, 900, or 1000° C. In some embodiments, the process comprises melting an ion-conductor material or combination of ion-conductor materials or precursors to ion conductor materials and moulding, flowing, or pressing the melt into shape.

[0050] Examples

[0051] Raw materials:

[0052] Succinic anhydride: (Sigma-Aldrich)

[0053] Maleic anhydride: (Sigma-Aldrich)

[0054] Trimellitic anhydride: (Sigma-Aldrich)

[0055] Pyromellitic dianhydride: (Sigma-Aldrich)

[0056] Dodecenyl succinic anhydride: (Sigma-Aldrich)

[0057] Pentadecenyl succinic anhydride: (Sigma-Aldrich)

[0058] 1 ,2,3,6-Tetrahydrophthalic anhydride: (Sigma-Aldrich)

[0059] Hexahydrophthalic anhydride: (Sigma-Aldrich)

[0060] RICACID TMEG-500: Mixture of 1 ,2,4-benzentricarboxylic acid, ester with 1 ,2-ethanediol (90%) and trimellitic anhydride (10%) (New Japan Chemical)

[0061] Lutensol ON 50: RO(CH2CH2O)XH, R = saturated, synthetic, short-chain fatty alcohol, x = 5 (BASF)

[0062] Lutensol AO 5: C13-C15 Alkoxylated polyethyleneglycol (number of ethylene oxide unit: 5) (BASF)

[0063] Lutensol AO 11 : C13-C15 Alkoxylated polyethyleneglycol (number of ethylene oxide unit: 11) (BASF)

[0064] Lutensol XL 100: C10 Guerbet alcohol alkoxylate (number of ethylene oxide unit: 10) (BASF)

[0065] Plurafac LF 224: Alkoxylated, predominantly unbranched fatty alcohols and higher alkene oxides alongside ethylene oxide (BASF) Polyglykol B01 / 40: Polypropylene glycol monobutyl ether (number of propylene oxide unit = 40) (Cl a ria nt)

[0066] BIKANOL M-1 / 1 ,25 B-500: RO[CH2C(CH3)O]x(CH2CH2O)yH, R = methyl, x = 4, y = 5 (Synovelle)

[0067] LEOSOLVE 703B: Polyoxyethylene-polyoxypropylene monobutyleter (Lion Specialty Chemicals)

[0068] PEG-200: Polyethylene glycol (number of ethylene oxide unit = 4) (Sigma-Aldrich)

[0069] PEG-400: Polyethylene glycol (number of ethylene oxide unit = 9) (Sigma-Aldrich)

[0070] MPEG-350: Methoxy polyethylene glycol (number of ethylene oxide unit = 8) (Sigma-Aldrich)

[0071] 5-Caprolactone: (Sigma-Aldrich)

[0072] 6-Valerolactone: (Sigma-Aldrich)

[0073] PPA: Polyphosphoric acid (Sigma-Aldrich)

[0074] KOH: Potassium hydroxide (Sigma-Aldrich)

[0075] DABCO: 1 ,4-Diazabicyclo[2.2.2]octane (Sigma-Aldrich)

[0076] DBSA: Dodecylbenzenesulfonic acid (Sigma-Aldrich)

[0077] Measurement of non-volatile content (solids content)

[0078] The sample (1 .0 ± 0.2 g of the tested substance) was weighed accurately into a previously dried aluminum dish and approximately 2 ml of Ethanol was added. After being homogenized, it is dried for 20 minutes at 150°C in the varnish drying cabinet, cooled in a desiccator and then reweighed. The residue corresponds to the solids content in the sample (ISO 3251).

[0079] Measurement of the acid value

[0080] 1.5 to 3.0 g of a sample was precisely weighed out into a 80 mL beaker and is dissolved with 50 mL of ethanol. Using an automatic titration device provided with a pH electrode, this solution was neutralization-titrated with a 0.1 mol / L ethanolic KOH solution. A flexion point of a titration pH curve was used as a titration endpoint, and an amine value was obtained by the following equation.

[0081] Acid value [mg KOH / g] = (561 x Q.1 x f x V) / (W x S)

[0082] (wherein f: factor of titration agent, V: titration amount at titration endpoint [mL], W: weighed amount of sample [g], S: solid matter concentration of sample [wt%]) Synthesis of Dispersant AD-1

[0083] 82.30 g of Lutensol ON 50, 17.60 g of succinic anhydride and 0.10 g of DABCO were added into a reaction vessel, and the reaction vessel was heated up to 80°C. Synthesis of Dispersant AD-1 was carried out at 80°C for 1 hour.

[0084] Dispersant AD-1 had 100% of solid content, 97 mg KOH / g of acid value of polymer and 498 g / mol of theoretical molecular weight (Details were described in Table 1).

[0085] Synthesis of Dispersants AD-2 - AD-8

[0086] Dispersants AD-2 - AD-8 were synthesized using the same procedure as used for Dispersant AD-1 , except using different types and amounts of anhydrides and alcohols (Details were described in Table 1)

[0087] Synthesis of Dispersants AD-9 - AD-16

[0088] Dispersants AD-9 - AD- 16 were synthesized using the same procedure as used for Dispersant AD-1 , except using different types and amounts of anhydrides and alcohols (Details were described in Table 2)

[0089] Synthesis of Comparative Dispersants AD-17 - AD-22

[0090] Dispersants AD-17 - AD-22 were synthesized using the same procedure as used for Dispersant AD-1 , except using different types and amounts of catalysts, anhydrides and alcohols (Details were described in Table 3)

[0091] Synthesis of Comparative Dispersant AD-23

[0092] 44.96 g of MPEG-350, 27.86 g of S-caprolactone, 16.72 g of b-valerolactone and 0.12 g of DBSA were added into a reaction vessel, and the reaction vessel was heated up to 80°C. The reaction was carried out at 80°C for 1 hour. After that, 10.34 g of PPA was added to the reaction vessel. Synthesis of Dispersant AD-23 was carried out at 80°C for 1 hour.

[0093] Dispersant AD-23 had 100% of solid content, 137 mg KOH / g of acid value of polymer and 797 g / mol of theoretical molecular weight (Details were described in Table 3). Synthesis of Comparative Dispersant AD-24

[0094] 44.42 g of MPEG-350, 27.52 g of S-caprolactone, 16.52 g of 5-valerolactone and 0.11 g of DBSA were added into a reaction vessel, and the reaction vessel was heated up to 80°C. The reaction was carried out at 80°C for 1 hour. After that, 11 .43 g of succinic anhydride was added to the reaction vessel. Synthesis of Dispersant AD-24 was carried out at 80°C for 1 hour.

[0095] Dispersant AD-24 had 100% of solid content, 64 mg KOH / g of acid value of polymer and 757 g / mol of theoretical molecular weight (Details were described in Table 3). Table 1 : Recipes of Dispersants AD-1 - AD-8 Table 2: Recipes of Dispersants AD-9 - AD-16

[0096] Table 3: Recipes of Comparative Dispersants AD-17 - AD-24 Production of metal oxide dispersions used for battery application

[0097] LLZO: Li6.4La3Zr2AI0.2O12, purity: 99% (MATERION)

[0098] Xylene: (Sigma-Aldrich) General procedure for producing Dispersion L-1 used for battery application

[0099] 0.5 g of Dispersant AD-1 described above was placed into a 70 ml glass bottle. After that, 9.5 g of Xylene was added to the glass bottle to dissolve Dispersant AD-1. Then, 10.0 g of LLZO and 60 g of zirconia beads (diameter: 0.4 - 0.6 mm, components: ZrO2 / Y2Oa = 95% / 5%) were added into the glass bottle. The dispersion process was performed in a LAU-Disperser DAS 200 over a period of 3 hours at 30°C. After removing the zirconia beads, the dispersion was filtered into a 50 ml glass bottle and named Dispersion L-1.

[0100] General procedure for producing Dispersions L-2 - L-24 used for battery application

[0101] Dispersions L-2 - L-24 were produced according to the procedure of Dispersion L-1 (Details were described in Table 4).

[0102] Table 4: Recipes of Dispersions L-1 - L-24 used for battery application

[0103] Comparative Examples are marked by test results

[0104] PVDF: Polyvinylidene difluoride, product name: Solef 5130 (Solvay)

[0105] Carbon black: Product name: Denka black Li 400 (Denka)

[0106] Production of Model cells AD- 1 - AD-24 for anode

[0107] 12 g of PVDF was dissolved in 88 g of NMP to prepare PVDF NMP solution. Then, 0.7 g of Dispersant AD-1 , 0.7 g of PVDF NMP solution and 30 g of NMP were placed into a 70 ml plastic vessel and stirred by using Dispermat CV at 1000 rpm for 10 minutes. After that, 1.0 g of carbon black was added gradually under stirring. After finishing the addition of carbon black, the ingredients were stirred by using Dispermat CV at 1000 rpm for 10 minutes to produce Slurry AD- 1.

[0108] Slurry AD-1 was coated to a copper foil (wiped by using ethanol) by using an applicator (wet film thickness: 6 mil), and the coating film was dried on a hot plate (90°C) at 30 minutes to produce Anode electrode AD-1.

[0109] Mode cell AD-1 for anode was produced by building a Li foil, a separator including 150 pl of 1.0 mol / L LiPFe ethyl carbonate / diethyl carbonate (50 / 50, volume ratios) solution and Anode electrode AD-1 under a condition of argon atmosphere.

[0110] Model cells AD-2 - AD-24 for anode and Model cell Blank for anode (a model cell for anode without any dispersants) were produced according to the procedure of Model cell AD-1 for anode.

[0111] Production of Model cells AD- 1 - AD-24 for cathode

[0112] Slurry AD-1 described above was coated to an aluminum foil (wiped by using ethanol) by using the applicator (wet film thickness: 10 mil), and the coating film was dried on a hot plate (90°C) at 30 minutes to produce Cathode electrode AD-1.

[0113] Model cell AD-1 for cathode was produced by building the Li foil, the separator with 150 pl of 1.0 mol / L LiPFe ethyl carbonate / diethyl carbonate (50 / 50, volume ratios) solution and Cathode electrode AD-1 under the condition of argon atmosphere.

[0114] Model cells AD-2 - AD-24 for cathode and Model cell Blank for cathode (a model cell for cathode without any dispersants) were produced according to the procedure of Model cell AD- 1 for cathode.

[0115] Electrochemical stability of Dispersants AD-1 - AD-24 for anode Model cell AD-1 for anode described above was applied voltage (0.01 - 4.8 V) by using cyclic voltammetry machine (product name: MPG-2, Bio-Logic SAS) at 0.05 mV / s of scan rate to get a chart (waveform data). Electrochemical stability of Dispersant AD- 1 for anode was evaluated by preparing between the chart of Model cell AD-1 for anode and that of Model cell Blank for anode and marked as follows;

[0116] 1 (Excellent): There was no waveform gaps between the chart of Model cell AD-1 for anode and that of Model cell Blank for anode

[0117] 2 (Pass): a few waveform gaps existed in the chart of Model cell AD-1 for anode

[0118] 3 (Intermediate): Some waveform gaps existed in the chart of Model cell AD-1 for anode

[0119] 4 (NG): There are huge waveform gaps between the chart of Model cell AD-1 for anode and that of Model cell Blank for anode

[0120] Electrochemical stability of Dispersants AD-2 - AD-24 for anode were evaluated according to the procedure of the electrochemical stability of Dispersant AD-1 for anode.

[0121] Electrochemical stability of Dispersants AD-1 - AD-24 for cathode

[0122] Model cell AD-1 for cathode described above was applied voltage (0.01 - 4.8 V) by using cyclic voltammetry machine (product name: MPG-2, Bio-Logic SAS) at 0.05 mV / s of scan rate to get a chart (waveform data). Electrochemical stability of Dispersant AD-1 for cathode was evaluated by preparing between the chart of Model cell AD-1 for cathode and that of Model cell Blank for cathode and marked as follows;

[0123] 1 (Excellent): There was no waveform gaps between the chart of Model cell AD-1 for cathode and that of Model cell Blank for cathode

[0124] 2 (Pass): a few waveform gaps existed in the chart of Model cell AD-1 for cathode

[0125] 3 (Intermediate): Some waveform gaps existed in the chart of Model cell AD-1 for cathode

[0126] 4 (NG): There are huge waveform gaps between the chart of Model cell AD-1 for cathode and that of Model cell Blank for cathode

[0127] Electrochemical stability of Dispersants AD-2 - AD-24 for cathode were evaluated according to the procedure of the electrochemical stability of Dispersant AD-1 for cathode.

[0128] Confirmation of ash component of Dispersants AD- 1 - AD-24

[0129] 1.0 g of Dispersant AD-1 described above was measured with an accuracy of 0.0001 g and added into a previously ignition-treated quartz fiber crucible. In order to remove organic components in Dispersant AD-1 , pre-ignition of the sample was carried out at 400°C for 15 minutes by using a rapid incinerator. After the pre-ignition, the sample was placed in an incinerator (Laboratory chamber furnace K 114, Thermo Electron LED GmbH) and heated up to 600°C. The ignition was carried out at 600°C for 30 minutes. After cooling down, the sample after ignition was measured again. Ash content was obtained by the following equation.

[0130] Ash content [%] = W2 / W1 x 100

[0131] (wherein W initial weighed amount of sample [g], W2: weighed amount of sample after ignition [g])

[0132] Confirmation of ash component of Dispersant AD-1 was marked as follows;

[0133] 1 (Excellent): There was no residue in the crucible after ignition, and ash content was less than 0.1%

[0134] 2 (Poor): Some residues existed in the crucible after ignition even though ash content was less than 0.1 %

[0135] 3 (Miserable): Residues existed in the crucible after ignition, and ash content was more than 0.1%

[0136] Confirmation of ash component of the Dispersants AD-2 - AD-24 were marked as the same procedure of the Dispersant AD- 1.

[0137] Particle size of Dispersions L-1 - L-24

[0138] Particle sizes at 10% of cumulative particle size distribution (D10), 50% of cumulative particle size distribution (D50) and 90% of cumulative particle size distribution (D90) of Dispersions L- 1 - L-24 were measure by using Particle Size Analyzer ELSZ-1000 (Otsuka Electronics).

[0139] Examples 1 - 16: Electrochemical stability (for anode and cathode) and confirmation of ash component of Dispersants AD- 1 - AD-16 and particle size (D10, D50 and D90) of Dispersions L-1 - L-16

[0140] Electrochemical stability for anode and cathode of Dispersants AD-1 - AD-16, confirmation of ash component of Dispersants AD-1 - AD-16 and particle size (D10, D50 and D90) of Dispersions L-1 - L-16 were described in Table 5. Table 5: Electrochemical stability (for anode and cathode) and confirmation of ash component of Dispersants AD-1 - AD-16 and particle size (D10, D50 and D90) of Dispersions L-1 - L-16

[0141] Comparison examples 1 - 8: Electrochemical stability (for anode and cathode) and confirmation of ash component of Dispersants AD-17 - AD-24 and particle size (D10, D50 and D90) of Dispersions L-17 - L-24

[0142] Electrochemical stability for anode and cathode of Dispersants AD-17 - AD-24, confirmation of ash component of Dispersants AD-17 - AD-24 and particle size (D10, D50 and D90) of Dispersions L-17 - L-24 were described in Table 6. Table 6: Electrochemical stability (for anode and cathode) and confirmation of ash component of Dispersants AD-17 - AD-24 and particle size (D10, D50 and D90) of Dispersions L-17 - L- 24

[0143] According to the results in Table 5, Dispersants AD-1 - AD-16, which had one carboxylic acid group and were produced by an esterification reaction between monoanhydride and monoalcohol using organic catalyst, showed excellent electrochemical stability and no ash components. Moreover, Dispersions L-1 - L-16 including AD-1 - AD-16, respectively, showed smaller particle size (D10, D50 and D90).

[0144] However, according to the results in Table 6, Dispersants AD- 17 and AD- 19 which had multiple carboxylic acid groups (Comparison examples C-1 and C-3) showed poor dispersibility as well as existence of ash components originated from an inorganic catalyst (KOH). Dispersants AD- 18, AD-20 and AD-21 , which were produced by an esterification reaction between dianhydride and monoalcohol (Comparison example C-2) or monoanhydride and dialcohol (Comparison examples C-4 and C-5) also showed poor dispersibility.

[0145] Dispersants AD-22 and AD-23 which had a phosphoric acid group (Comparison examples C- 6 and C-7) showed poor dispersibility as well as existence of huge amount of ash components originated from a phosphoric acid group. Dispersants AD-24, which were produced by an esterification reaction between caprolactones, monoalcohol and monoanhydride (Comparison examples C-8) showed poor dispersibility as well as existence of ash components originated from KOH.

Claims

Claims1. A composition comprising a) particles comprising lithium lanthanum zirconium oxide, and b) a polymer comprising a polyether segment, wherein the polymer comprises one alkyl ether end group and one carboxylic acid end group, wherein the carboxylic acid end group is linked to the polyether segment via a linking segment comprising a carboxylic acid ester group.

2. The composition according to claim 1 , the alkyl ether end group comprise alkyl groups having 1 to 32 carbon atoms.

3. The composition according to claim 1 or 2, wherein the polyether segment comprises polymerized units of ethylene oxide or propylene oxide, or combinations thereof.

4. The composition according to any one of the preceding claims, wherein the linking segment further comprises a hydrocarbyl group located between the ester group and the carboxylic acid group having 2 to 30 carbon atoms.

5. The composition according to any one of the preceding claims, wherein the polymer b) has a number average molecular weight in the range of 200 to 1500 g / mol.

6. The composition according to any one of the preceding claims, wherein the polymer has an acid value in the range of 25 to 250 mg KOH / g.

7. The composition according to any one of the preceding claims, wherein the composition further comprises an organic diluent which is liquid at a temperature of 20 °C.

8. The composition according to any one of the preceding claims, wherein the composition further comprises an organic binder polymer which is different from the polymer b).

9. The composition according to any one of the preceding claims, wherein the particles comprising lithium lanthanum zirconium oxide comprise a material of the formulaLiuLavZrxMeyOz, wherein u is in the range of 4 to 8; v is in the range of 2 to 4; x is in the range of 1 to 3; y is in the range of 0 to 1 ; z is in the range of 10 to 14;Me is a metal.

10. The composition according to any one of the preceding claims, wherein polymer b) is present in an amount of 0.5 to 20.0 % by weight, calculated on the weight of the particles comprising lithium lanthanum zirconium oxide.

11. Use of the composition according to any one of the preceding claims for preparing a battery comprising a solid electrolyte.

12. A solid electrolyte battery comprising the composition according to any one of the preceding claims 1 to 10.

13. Use of a polymer comprising a polyether segment, wherein the polymer comprises one alkyl ether end group and one carboxylic acid end group, wherein the carboxylic acid end group is linked to the polyether segment via a linking segment comprising a carboxylic acid ester group for dispersing solid particles comprising lithium lanthanum zirconium oxide.

14. A process of preparing an ion-conductive membrane or separator for an electrochemical device, wherein the composition according to any one of the preceding claims 1 to 10 is employed for producing the membrane or separator.

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