DE102017217654A1 - Electrochemical cell comprising at least one molecular sieve - Google Patents

Abstract

The invention relates to an electrochemical cell (1) comprising at least one positive electrode (22), at least one negative electrode (21) and at least one electrolyte composition (15), wherein the negative electrode (21) comprises at least one active material (41) is reactive with protic compounds, in particular with respect to water, and wherein additionally at least one molecular sieve (50) is incorporated in the electrochemical cell (1).

Description

The invention relates to an electrochemical cell comprising at least one molecular sieve. The invention also relates to a corresponding battery comprising the electrochemical cell and its use. The subject matter is also the use of at least one molecular sieve in an electrochemical cell.

State of the art

The storage of electrical energy by means of electrochemical primary or secondary cell has been known for many years. In particular, secondary cells based on lithium in ionic or elemental form are the focus of research. Through the development of new active materials for the negative electrode (anode) and the positive electrode (cathode), the properties of the individual electrochemical cells and also of the batteries produced therefrom can be steadily improved.

Active materials commonly used in electrochemical cells are sometimes highly reactive towards electrochemical cell contaminants with protic compounds, especially compounds such as water and alcohols. This is the case in particular for electrochemical cells which use metallic lithium as the active material. Especially the presence of water in the materials which are used in the electrochemical cell can not always be sufficiently reduced under economically and technically reasonable conditions. In addition, low molecular weight compounds such as water can diffuse into the cell during operation of the cell or, if appropriate, can also be formed in undesirable side reactions in the cell. In particular, in electrochemical cells with anodes comprising elemental lithium, this can lead to unwanted, sometimes violent reactions.

JP 1995-252999 discloses an electrochemical cell comprising a liquid electrolyte containing an absorbent having a pore diameter smaller than the effective diameter of the solvent of the electrolyte and having absorption properties to polar molecules such as water.

KR 2003-0013851 discloses an energy storage device comprising an organic electrolyte containing up to 20% by weight of a zeolite. The organic electrolyte is an aprotic, polar solvent such as an alkyl carbonate or acetonitrile.

Disclosure of the invention

The present invention relates to an electrochemical cell comprising at least one positive electrode, at least one negative electrode and at least one electrolyte composition, wherein the negative electrode comprises at least one active material which is reactive with protic compounds, in particular with respect to water, and wherein additionally at least one molecular sieve in the electrochemical cell is incorporated.

The electrochemical cell according to the invention comprises at least one positive electrode and at least one negative electrode. The electrodes each comprise an electrically conductive current collector, also called a collector, and an active material applied thereto. The current collector includes, for example, copper or aluminum as an electrically conductive material. In a preferred embodiment, the current conductor of the electrodes is made of aluminum.

The positive electrode active material is capable of reversibly releasing lithium ions in an electrochemical reaction. Suitable materials are known to the person skilled in the art. For example, lithiated intercalation compounds which are capable of reversibly taking up and liberating lithium ions are suitable.

The positive electrode active material (hereinafter also referred to as positive active material) may comprise a composite oxide containing at least one metal selected from the group consisting of cobalt, magnesium, nickel, and lithium.

One embodiment of the present invention includes a positive active material comprising a compound of the formula LiMO ₂ wherein M is selected from Co, Ni, Mn or mixtures thereof and mixtures of these with Al. In particular, LiCoO ₂ should be mentioned.

In a preferred embodiment, the positive active material is a material comprising nickel, ie LiNi _1-x M ' _x O ₂ , where M' is selected from one or more of Co, Mn and Al and 0 ≤ x <1 is. Examples include lithium nickel cobalt aluminum oxide cathodes (eg, LiNi _0.8 Co _0.15 Al _0.05 P ₂ ; NCA) and lithium nickel manganese cobalt oxide cathodes (eg, LiNi _0.8 Mn _0.1 Co _0.1 O ₂ (NMC (811)), LiNi _0.33 Mn _0.33 Co _0.33 O ₂ (NMC (111)), LiNi _0.6 Mn _0.2 Co _0.2 O ₂ (NMC (622)), LiNi _0.5 Mn _0.3 Co _0.2 O ₂ (NMC (532)) or LiNi _0.4 Mn _0.3 Co _0.3 O ₂ (NMC (433)) ,

Further, as preferred positive active materials, mention may be made of overithiated oxides which are known in the art. Examples of these are layer oxides of the general formula n (Li ₂ MnO ₃ ): 1-n (LiMO ₂ ) where M = Co, Ni, Mn, Cr and 0 ≦ n ≦ 1 and spinels of the general formula n (Li ₂ MnO ₃ ) : 1-n (LiM ₂ O ₄ ) with M = Co, Ni, Mn, Cr and 0 ≤ n ≤ 1.

Furthermore, in particular spinel compounds of the formula LiM _x Mn _2-x O ₄ with M = Ni, Co, Cu, Cr, Fe (eg LiMn ₂ O ₄ , LiNi _0.5 Mn _1.5 O ₄ ), olivine compounds of the formula LiMPO ₄ with M = Mn , Ni, Co, Cu, Cr, Fe (eg LiFePO ₄ , LiMnPO ₄ ), silicate compounds of the formula Li ₂ MSiO ₄ with M = Ni, Co, Cu, Cr, Fe, Mn (eg Li ₂ FeSiO ₄ ), tavorite compounds ( eg LiVPO ₄ F), Li ₂ MnO ₃ , Li _1.17 Ni _0.17 Co _0.1 Mn _0.56 O ₂ and Li ₃ V ₂ (PO ₄ ) ₃ as suitable positive active materials. Furthermore, conversion materials such as SPAN (polyacrylonitrile, which has been reacted with an excess of sulfur at elevated temperature in the range 300 ° C-500 ° C and thereby formed sulfur side chains and bridges), iron fluoride (FeF ₃ ) or iron oxyfluorides ( FeOF) suitable positive active materials.

The active material of the negative electrode (hereinafter also referred to as negative active material) comprises at least one material which is reactive with protic compounds, in particular with respect to water and / or alcohols. Examples of such active materials are in particular materials which comprise alkali metals and / or alkaline earth metals in elemental form. In a preferred embodiment of the invention, the negative electrode active material comprises metallic lithium and / or sodium. In a particularly preferred embodiment, the active material of the negative electrode comprises metallic lithium or consists of metallic lithium.

As further components, the negative active material and / or the positive active material, in particular binders such as styrene-butadiene copolymer (SBR), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), carboxymethylcellulose (CMC), polyacrylic acid (PAA), polyvinyl alcohol (PVA) and Ethylene-propylene-diene terpolymer (EPDM) to increase the stability of the electrodes. Furthermore, conductive additives such as Leitruß or graphite may be added.

In addition, the electrochemical cell comprises at least one electrolyte or at least one electrolyte composition. Suitable electrolytes are in particular solid electrolytes and / or electrolyte compositions based on ionic liquids.

Solid electrolytes in the context of this invention are solids which have ionic conductivity for at least one type of ion. Examples of suitable solid electrolytes include LiTiCoO ₄ , Li ₂ PO ₂ N, Li ₄ Ti ₅ O ₁₂ , NASICON or LISICON type compounds (eg, compounds of the general formulas Li _{1 + x} Zr ₂ Si _x P ₃ -x O ₁₂ with 0 <x <3 or Li _{2 + 2x} Zn _1-x GeO ₄ with 0 <x <1), sulfidic glasses such as LSPS, garnet structures such as LLTO (Li _3x La _2/3-x TiO ₃ with x = 0, 1) or LLZO (Li ₇ La ₃ Zr ₂ O ₁₂ and polymer electrolytes.) The solid electrolyte or the solid electrolyte composition can also be used instead of the aforementioned binder in negative and / or positive active material.

In a preferred embodiment, the solid electrolyte composition is a polymer electrolyte composition. Suitable polymer electrolyte compositions comprise at least one polymer and at least one conducting salt. Suitable polymers are polyalkylene oxides, e.g. Polyethylene oxide (PEO) and polypropylene oxide (PPO), polymalonic acid esters, polyoxalic acid esters, polyacrylates, e.g. Poly [2- (2-methoxyethoxyethyl glycidyl ether)] (PMEEGE), polyphosphazenes, polysiloxanes, polyvinylidene fluoride (PVDF), polyvinylidene fluoride-copolyhexafluoropropylene (PVDF-HFP), polyacrylonitrile (PAN), and styrene-butadiene copolymers (SBR). In one embodiment, suitable polymer electrolyte compositions include copolymers of alkylene oxides and acrylates, phosphazenes, or siloxanes, with an acrylate, phosphazene, or siloxane polymer chain as the backbone substituted with polyalkylene chains as side chains.

Particularly preferred polymers include polyethylene oxide (PEO), copolymers of polyethylene oxide, polymalonic acid esters and / or polyoxalic acid esters.

Polyethylene oxide (also polyethylene glycol) is a polymer which is composed of the repeating unit (-CH ₂ -CH ₂ -O-) and preferably comprises 10 to 1000, in particular 20 to 500 repeating units per molecule. Copolymers of the polyethylene oxide include, in particular, block copolymers of at least one polyethylene oxide block and at least one block of an ionically or radically polymerizable monomer, in particular styrene or a styrene derivative (eg α-methylstyrene). A particularly preferred copolymer is a polyethylene oxide [b] polystyrene block copolymer.

mit R¹, R² = H oder F;
R³ = organischer Rest, insbesondere Alkylrest der Formel -(CH₂)_m-, wobei m eine ganze Zahl von 1 bis 10, vorzugsweise 2 bis 8, darstellt; und n = 2 bis 1000, insbesondere 10 bis 500.Polymalonic acid esters include repeat units of the general formula (I):

with R ¹ , R ² = H or F;
R ³ = organic radical, in particular alkyl radical of the formula - (CH ₂ ) _m -, where m is an integer from 1 to 10 , preferably 2 to 8th , represents; and n = 2 to 1000, in particular 10 up to 500.

mit R⁴ = organischer Rest, insbesondere Alkylrest der Formel -(CH₂)_q-, wobei q eine ganze Zahl von 1 bis 10, vorzugsweise 2 bis 8, darstellt; und
p = 2 bis 1000, insbesondere 10 bis 500.Polyoxalic acid esters include repeat units of the general formula (II):

with R ⁴ = organic radical, in particular alkyl radical of the formula - (CH ₂ ) _q -, where q is an integer from 1 to 10 , preferably 2 to 8th , represents; and
p = 2 to 1000, in particular 10 up to 500.

In addition, the polymer electrolyte composition may also comprise mixtures of the aforementioned polymers.

In a further alternative embodiment of the invention, the at least one electrolyte or the at least one electrolyte composition may also comprise or consist of an ionic liquid. In this case, the electrochemical cell preferably further comprises at least one separator. This may be a conventional separator.

Ionic liquids in the context of this invention are organic salts which do not form stable crystal lattices as a result of charge delocalization and steric effects. It therefore has a low melting temperature, which is preferably ≦ 75 ° C., more preferably ≦ 50 ° C., and especially ≦ 30 ° C.

Suitable cations of the ionic liquids include imidazolium, pyridinium, pyrrolidinium, guanidinium, uronium, thiouronium, piperidinium, morpholinium, ammonium and phosphonium cations, optionally with one or more alkyl radicals 1 to 6 Carbon atoms can be substituted. Particularly preferred are imidazolium, pyridinium, pyrrolidinium and ammonium cations, preferably with one or more alkyl radical (s) with 1 to 6 Carbon atoms can be substituted.

Suitable anions of the ionic liquid include halide, tetrafluoroborate, trifluoroacetate, triflate, hexafluorophosphate, phosphinate, tosylate, and bulky imide and amide anions. Preferably, the carbon atoms of the anions are perfluorinated. Particularly preferred are sterically demanding imide anions, in particular perfluorinated imide anions such as the bis (trifluoromethylsulfonyl) imide anion.

Preferred ionic liquids are 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, 1-methyl-1-propylpiperidinium bis (trifluoromethylsulfonyl) imide, 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide, butyltrimethylammonium bis ( trifluoromethylsulfonyl) imide, diethylmethyl (methoxyethyl) ammonium bis (trifluoromethylsulfonyl) imide, and mixtures thereof. Particularly preferred is 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide.

Furthermore, the electrolyte composition comprises at least one conductive salt. This is in particular an alkali metal salt. Particularly preferred are sodium and lithium salts, in particular lithium salts. Suitable examples of such lithium conductive salts include lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), LiSbF ₆ , LiAsF ₆ , Li (CF ₃ ) SO ₂ NSO ₂ (CF ₃ ) (LiTFSI), LiClO ₄ , lithium bis (oxalato) borate (Li [B (C ₂ O ₄ ) ₂ ], LiBOB) and lithium difluoro (oxalato) borate (Li [BF ₂ (C ₂ O ₄ ], LiDFOB), which may each be used singly or in combination the at least one conductive salt makes up a proportion of 1 to 5% by weight, in particular 2 to 3% by weight, of the total weight of the electrolyte composition.

An essential feature of the electrochemical cell according to the invention is that it comprises at least one molecular sieve. A molecular sieve in the sense of this invention is a natural or synthetic silicate which has a strong adsorption capacity to gases, vapors and / or solutes. Molecular sieves have pores of uniform size which have a pore diameter in the range of the effective molecular diameters of the molecules to be adsorbed. They can thus absorb molecules reversibly or irreversibly and bind preferably by weak interactions, in particular hydrogen bonds. Typically, the molecular sieves have an internal surface area of 600 to 700 m ² / g.

In a preferred embodiment of the invention, the molecular sieve is suitable for adsorbing low molecular weight compounds, in particular protic, low molecular weight compounds such as water, methanol or ethanol, in particular water. Low molecular weight compounds in the context of this invention have a molecular weight of not more than 50 g / mol. In order to achieve the adsorption of such compounds, molecular sieves are preferably used which have a pore diameter of 2 to 5 Ä, more preferably 3 to 4 Ä have.

Preferably, natural or synthetic zeolites are used as molecular sieves. Zeolites are alkali or alkaline earth cations containing aluminum silicates of the general structure M _{2 / n} O • Al ₂ O ₃ • x SiO ₂ • y H ₂ O with M = alkali or alkaline earth metal cation; n = valency of the cation M; x ≥ 2. y may vary depending on the degree of hydration. Preferably, it is incorporated into the electrochemical cell in a mold with y ≦ 3, in particular y = 0.

Particularly preferred is the use of zeolite A (Na ₁₂ ((AlO ₂ ) ₁₂ (SiO ₂ ) ₁₂ · 27H ₂ O) as a molecular sieve, especially in its fully dehydrogenated form Na ₁₂ ((AlO ₂ ) ₁₂ (SiO ₂ ) ₁₂ ).

The molecular sieve is preferably used in the form of molecular sieve particles having an average particle diameter of not more than 100 μm, more preferably not more than 50 μm, in particular not more than 20 μm, and particularly preferably not more than 10 μm.

In one embodiment of the invention, the at least one molecular sieve is incorporated into the positive electrode active material. Due to the polar nature of the positive electrode active material, it is particularly demanding to completely remove polar contaminants such as water from this material. The active material of the positive electrode is thus potentially a component with which molecules of protic, low molecular weight compounds, in particular water molecules, can get into the electrochemical cell. In order to intercept and bind these protic molecules as they are desorbed from the surface of the positive active material, the at least one molecular sieve in this embodiment is incorporated into the positive active material composition in direct contact with the positive active material. Preferably, at least one of the aforementioned binders is used to achieve a stable positive active material composition. Alternatively, the solid electrolyte composition can be used as a binder. Preferably, the molecular sieve is incorporated in an amount of ≦ 5% by weight, preferably 0.1 to 3% by weight, more preferably 1 to 2% by weight, based on the positive electrode active material in the active material composition.

In an alternative embodiment of the invention, the at least one molecular sieve is incorporated into at least one solid electrolyte composition. The solid electrolyte composition located between the positive and negative electrodes is thus suitable for protecting the protic compound-sensitive negative electrode active material from both low molecular weight protic compounds, especially from water molecules derived from the positive-electrode positive active material Such low molecular weight protic compounds such as water molecules, which originate from the solid electrolyte composition itself or may be formed during operation of the electrochemical cells in a region of the cell by an undesirable side reaction and / or diffuse from the outside through the cell housing in the electrochemical cell.

In addition, the addition of molecular sieve to the solid electrolyte composition increases its mechanical stability. The mechanical stability of a solid electrolyte composition, especially if it is a polymer electrolyte composition, depends on the melting or softening temperature and the solid electrolyte used, the type and amount of the further additives and the operating temperature of the electrochemical cell. Since the ionic conductivity of a solid electrolyte composition is usually low at room temperature, solid state electrochemical cells are often operated at temperatures higher than 80 ° C. Frequently, softening of the solid electrolyte composition, in particular of the polymer of a polymer electrolyte composition, already occurs at these temperatures. By adding molecular sieves, in particular zeolites, the stability of the solid electrolyte composition, in particular of a polymer electrolyte composition, can be improved and the safety of the electrochemical cells can be increased.

The molecular sieve is preferably incorporated in an amount of ≦ 10% by weight, preferably 0.1 to 5% by weight, in particular 1 to 2% by weight, based on the weight of the solid electrolyte composition. This is done, for example, by melting the solid electrolyte composition and mixing the molten solid electrolyte composition with the molecular sieve and optionally further additives contained. Alternatively, for example, the molecular sieve can already be incorporated into it during the production of the solid electrolyte composition. For example, the molecular sieve may be incorporated into a powdery composition of the constituents of the solid electrolyte composition and then jointly hot pressed and / or calendered.

In another alternative embodiment, the molecular sieve is incorporated in both the solid electrolyte composition and the positive electrode active material composition. This will provide as much protection as possible moisture-sensitive active material of the negative electrode.

The electrochemical cell according to the invention can advantageously be used in a lithium-containing battery. In this case, a battery comprises at least one, preferably at least two electrochemical cells. An electrochemical cell according to the invention or a battery produced therefrom advantageously finds use in an electric vehicle (EV), in a hybrid vehicle (HEV), in a plug-in hybrid vehicle (PHEV), in a tool or in a consumer electronics product. Under tools are in particular home tools and garden tools to understand. Consumer electronics products are in particular mobile phones, tablet PCs or notebooks.

The invention also provides the use of at least one molecular sieve for absorbing protic, low molecular weight compounds, in particular water and / or alcohols, in an electrochemical cell which comprises at least one negative electrode which comprises a material which is resistant to protic compounds, in particular to water and / or alcohols is reactive.

The invention likewise provides methods for binding low molecular weight compounds in an electrochemical cell, the method comprising introducing molecular sieves into the electrochemical cell.

Advantages of the invention

The electrochemical cell according to the invention is characterized in that due to the low water concentration in the electrochemical cell, the surface of the moisture-sensitive active material of the negative electrode comes into contact only slightly with water molecules. Thus, no or only a very small cover layer forms on the active material surface of the anode, which is formed by the reaction of the active material with low molecular weight protic compounds such as water. The electrochemical cell according to the invention is characterized by a lower internal resistance, better C-rate performance and increased long-term stability. The performance of the electrochemical cell is maintained over a much longer period of time. In addition, the addition of at least one molecular sieve to a solid electrolyte composition increases its stability, especially at elevated temperatures. This further improves the safe time of the electrochemical cell. In addition, the addition of the particles reduces the crystallinity of the solid electrolyte composition and thus increases the ionic conductivity thereof.

list of figures

• 1 eine schematische Darstellung einer erfindungsgemäßen elektrochemischen Zelle;
• 2 eine alternative schematische Darstellung einer erfindungsgemäßen elektrochemischen Zelle;
• 3 eine weitere alternative schematische Darstellung einer erfindungsgemäßen elektrochemischen Zelle.

It shows:

• 1 a schematic representation of an inventive electrochemical cell;
• 2 an alternative schematic representation of an electrochemical cell according to the invention;
• 3 a further alternative schematic representation of an electrochemical cell according to the invention.

Embodiments of the invention

In 1 is an electrochemical cell 1 shown schematically. The electrochemical cell 1 includes a cell housing 2 , The cell case 2 In the present case, it is designed to be electrically conductive and, for example, made of aluminum. The cell case 2 but can also be made of an electrically insulating material, such as plastic.

The electrochemical cell 1 includes a negative terminal 11 and a positive terminal 12 , About the terminals 11 . 12 can be one of the electrochemical cell 1 provided voltage can be tapped. Furthermore, the electrochemical cell 1 over the terminals 11 . 12 also be loaded. The terminals 11 . 12 are spaced from each other on a top surface of the cell housing 2 arranged.

Inside the cell housing 2 At least two electrodes are arranged, namely at least one negative electrode 21 and at least one positive electrode 22 , The negative electrode 21 and the positive electrode 22 are each made like a foil and spaced from each other. Between the negative electrode 21 and the positive electrode 22 is an electrolyte composition 15 arranged. This is embodied here as a solid electrolyte composition, in particular a polymer electrolyte composition, and thus separates the negative electrode 21 and the positive electrode 22 from each other.

The negative electrode 21 includes an active material 41 , which is designed like a film. The active material 41 the negative electrode 21 comprises at least one moisture-sensitive material, in particular lithium or a lithium-containing alloy.

The negative electrode 21 further includes a current collector 31 , which also foil-like is trained. The active material 41 the negative electrode 21 and the current collector 31 the negative electrode 21 are laid flat against each other and connected to each other. The current collector 31 the negative electrode 21 is made electrically conductive and made of a metal, such as copper. The current collector 31 the negative electrode 21 is electric with the negative terminal 11 the electrochemical cell 1 connected.

At the positive electrode 22 In the present case, this is, for example, an NCM (nickel-cobalt-manganese) electrode. Alternatively, for example, NCA (nickel-cobalt-aluminum) or lithium-iron phosphate electrodes can be used. The positive electrode 22 includes an active material 42 which is in particulate form. Between the particles of the active material 42 the positive electrode 22 are additives, in particular conductive carbon black and binder arranged. The active material 42 and said additives form a composite, which is designed like a film.

The positive electrode 22 further includes a current collector 32 , which is also formed like a film. The composite of the active material 42 the positive electrode 22 and the additives and the current collector 32 are laid flat against each other and connected to each other. The current collector 32 the positive electrode 22 is made electrically conductive and made of a metal, such as aluminum. The current collector 32 the positive electrode 22 is electric with the positive terminal 12 the electrochemical cell 1 connected.

The cell case 2 the electrochemical cell 1 is with an electrolyte composition 15 , in this case in particular a polymer electrolyte composition filled. The solid electrolyte composition 15 separates the negative electrode 21 and the positive electrode 22 from each other. Also the electrolyte composition 15 is ionically conductive and includes, for example, polyethylene oxide (PEO) as the polymer and Li (CF ₃ ) SO ₂ NSO ₂ (CF ₃ ) (LiTFSI) as the conductive salt.

In 1 is an electrochemical cell according to the invention 1 shown in direct contact with the active material 42 the positive electrode 22 at least one molecular sieve 50 in the composite of active material 42 the positive electrode 22 and the optional additives incorporated. As a molecular sieve 50 For example, zeolite A particles, preferably having a particle size of less than 10 to 20 microns, are used.

In 2 is a modification of the electrochemical cell 1 out 1 shown schematically. The modified electrochemical cell 1 also includes a cell housing 2 and is largely similar to the electrochemical cell 1 out 1 , Unlike the electrochemical cell 1 out 1 is in the electrochemical cell 1 out 2 the at least one molecular sieve 50 in the electrolyte composition 15 , which is designed as a polymer electrolyte composition incorporated. As a molecular sieve 50 For example, zeolite A particles, preferably having a particle size of less than 10 to 20 microns, are also used.

Finally shows 3 another corresponding modification of the electrochemical cell 1 which differs from that of the electrochemical cells 1 out 1 and 2 differentiates that at least one molecular sieve 50 both in the composite of active material 42 the positive electrode 22 and the optionally used additives as well as in the electrolyte composition 15 , which is designed as a polymer electrolyte composition, is incorporated. This ensures optimal binding of the water molecules and optimal protection of the active material 41 the negative electrode 21 achieved.

The invention is not limited to the embodiments described herein and the aspects highlighted therein. Rather, within the scope given by the claims a variety of modifications are possible, which are within the scope of expert action.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 7252999 [0004]
• KR 20030013851 [0005]

Claims (10)

An electrochemical cell (1) comprising at least one positive electrode (22), at least one negative electrode (21) and at least one electrolyte composition (15), said negative electrode (21) comprising at least one active material (41) reactive with protic compounds , in particular to water, and wherein additionally at least one molecular sieve (50) is incorporated in the electrochemical cell (1). Electrochemical cell (1) after Claim 1 wherein the at least one molecular sieve (50) is incorporated in the active material (42) of the positive electrode (22). Electrochemical cell (1) after Claim 1 or 2 wherein the electrolyte composition (15) is a solid electrolyte composition and the at least one molecular sieve (50) is incorporated in the solid electrolyte composition. Electrochemical cell (1) according to one of Claims 1 to 3 wherein the molecular sieve (50) is suitable for reversibly binding low molecular weight compounds, in particular water molecules. Electrochemical cell (1) according to one of Claims 1 to 4 wherein the molecular sieve (50) has a pore diameter of 3 to 4 Å. Electrochemical cell (1) according to one of Claims 1 to 5 wherein the molecular sieve (50) comprises at least one zeolite, in particular zeolite A. Lithium-ion battery, comprising at least one electrochemical cell (1) according to one of Claims 1 to 6 , Use of an electrochemical cell (1) according to one of Claims 1 to 6 and / or a lithium-ion battery Claim 7 in an electric vehicle (EV), in a hybrid vehicle (HEV), in a plug-in hybrid vehicle (PHEV), in a tool or in a consumer electronics product. Use of at least one molecular sieve (50) for absorbing protic, low molecular weight compounds, in particular water and / or alcohols, in an electrochemical cell (1) which comprises at least one negative electrode (21) comprising a material which is resistant to protic compounds, especially reactive towards water and / or alcohols. A method of binding low molecular weight compounds in an electrochemical cell (1), the method comprising introducing at least one molecular sieve (50) into the electrochemical cell (1).

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