EP3692586A1

EP3692586A1 - Electrode comprising elemental lithium, and manufacturing process

Info

Publication number: EP3692586A1
Application number: EP18780035.4A
Authority: EP
Inventors: Heiko Graebe
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2017-10-05
Filing date: 2018-09-19
Publication date: 2020-08-12
Also published as: DE102017217656A1; WO2019068463A1

Abstract

The invention relates to an electrode for an electrochemical cell, comprising at least one current collector and at least one active material composition which contains at least one active material, elemental lithium and at least one binder and which is made without using solvents.

Description

Description title

Electrode comprising elemental lithium and manufacturing process

The invention relates to an electrode for an electrochemical cell, in particular a solid-state cell, which in addition to an active material elemental lithium and was prepared without the addition of solvents. The subject matter is also the manufacturing process and the use of the electrode in a solid state cell.

State of the art

The storage of electrical energy by means of electrochemical primary or secondary batteries has been known for many years. In particular

Secondary batteries 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.

Conventional electrochemical secondary batteries, such as

Lithium-ion batteries, often use graphite as an anode active material, which is characterized by good Coloumb efficiency and low

Charge loss in the first charge cycle is characterized. During operation of such an electrochemical cell is formed on the surface of the

Active material a so-called solid-electrolyte interphase (SEI). This is due to the reaction of the active material with the remaining components of the electrochemical cell, such as lithium. While the formation of a (as defined) SEI is sometimes desired, the loss of lithium from the electrochemical cell is generally undesirable. The lithium is thereby removed from the electrochemical reaction for energy storage. This adversely affects the performance of the electrochemical cell. The prior art therefore describes processes which serve to introduce additional lithium into the electrochemical cell. The additional lithium is intended to compensate for the loss of lithium occurring during the later operation of the electrochemical cell due to the formation of the SEI. For this example, elemental lithium or organolithium compound in the

Active material introduced. These processes have the disadvantage that both compounds are highly reactive and in the preparation of the electrode with the commonly used solvents or contained therein

Impurities (such as traces of water) can react. Thus, there is further loss of lithium, as well as the formation of by-products (e.g., LiOH,

H2), which may negatively affect the performance of the electrochemical cell.

Disclosure of the invention

The invention relates to an electrode for an electrochemical cell, comprising at least one current collector and at least one

An active material composition, wherein the active material composition comprises at least one active material, elemental lithium and at least one

Binder comprises and was prepared without the use of solvents.

The current collector consists of an electrically conductive material. Suitable materials from which the current collector may be formed are, for example, aluminum, copper, nickel or even alloys of these metals. Particularly preferred are aluminum and / or copper. The layer thickness of the current collector is not particularly limited and ranges for example from 1 to 500 μηη, in particular from 5 to 200 μηη. Preferably, the current collector is designed flat.

According to the invention, the active material composition comprises at least one active material, elemental lithium and at least one binder and is arranged on at least one surface of the at least one current collector and electrically conductively connected thereto. In principle, any active material which is suitable as the active material of an electrode of an electrochemical cell and optionally undergoes an irreversible reaction with the lithium contained in the cell to form a solid electrolyte interphase (SEI) and the lithium may be used as the active material so that

Can remove electricity storage process. In a preferred

Embodiment, the active material comprises a carbon-based active material. In a particularly preferred embodiment, the active material comprises graphite or consists of graphite. Graphite is particularly suitable as an active material for negative electrodes (anodes) of electrochemical cells and is characterized by a good Coloumb efficiency and low charge loss in the first charge cycle. During the first charge cycles, however, irreversible reactions with lithium lead to SEI formation on the surface of the graphite. This is a loss of lithium, which is available for energy storage in the electrochemical cell connected.

Preferably, the graphite is used in the form of particles. These preferably have an average particle size of> 0.1 nm and <100 μm, more preferably in a range of> 1 nm and <1 μm, in particular in a range of> 10 nm and <100 nm.

In order to compensate for the loss of lithium by the irreversible reaction with the active material, the active material composition additionally comprises elemental (metallic) lithium. The lithium may in principle be in any form within the active material composition, e.g. in the form of particles, foils, strips, wires and / or pieces. Preferably, however, the lithium is distributed as homogeneously as possible in the active material composition, so that in a particularly preferred embodiment the lithium is in the form of particles in the active material composition.

Particles in the sense of this invention are particles of a uniform chemical composition which can be delimited from the environment by a surface and have an average particle diameter of less than 1 mm. The smallest particle in the sense of this definition consists of at least two identical atoms or molecules, eg two lithium atoms. Preferably, the lithium particles according to the present invention have an average particle diameter of> 0.1 nm to <100 μηη, more preferably from> 1 nm to <1 μηη, in particular from> 10 nm to <100 nm.

Films in the sense of this invention are planar structures of a uniform chemical composition, which is defined by a surface of the

Surrounding neighborhood and their greatest extent in two of the three spatial directions at least ten times, preferably at least one hundred times, especially at least one thousand times the extent to the third

Spatial direction corresponds. For example, lithium foils have a thickness (i.e., an extension in the third spatial direction) of> 0.1 nm to <100 μm, more preferably from> 1 nm to <1 μm, in particular from> 10 nm to <100 nm.

Strips in the sense of this invention are flat structures of a uniform chemical composition which can be obtained by or from the surface of the

Surround boundaries and their largest extension in one of the three spatial directions at least ten times, preferably at least one hundred times, especially at least one thousand times the extent to the second

Direction of space, as well as at least ten times, preferably at least fifty times, in particular at least one hundred times the extent to the third

Spatial direction corresponds. Lithium strips have, for example, a thickness (ie an extension in the second spatial direction) of> 0.1 nm to <100 μm, more preferably from> 1 nm to <1 μm, in particular from> 10 nm to <100 nm and can be achieved, for example the cutting of films are obtained.

For the purposes of this invention, wires are three-dimensional structures of a uniform chemical composition that can be delimited from the environment by a surface and whose greatest extent is essentially equal in two of the three spatial directions and whose expansion in the third spatial direction is at least ten times, preferably at least

one hundred times, in particular at least one thousand times the extent in the first and second spatial direction corresponds. Lithium wires are preferred an extent in two of the three spatial directions of the second spatial direction of> 0.1 nm to <1 mm, more preferably of> 1 μηη to <1 mm,

in particular of> 100 μηη to <0.5 mm and in their extension in these two spatial directions by not more than 50% from each other.

Pieces in the sense of this invention are particles of a uniform chemical composition which can be delimited from the environment by a surface and have an average particle diameter of> 100 μm. Preferably, lithium pieces according to the present invention have an average particle diameter of> 0.5 mm to <1 cm, more preferably from> 1 mm to <10 mm, in particular from> 1 mm to <5 mm.

Preferably, the lithium is used in an amount sufficient to compensate for the loss of lithium through the formation of the SEI. This amount depends on the active material and the operating conditions of the

electrochemical cell during the first charge cycles dependent. Generally, the lithium is used in an amount of 0.1 to 5 wt .-%, preferably 0.1 to 1 wt .-%, based on the total weight of the active material of the electrode. The elemental (metallic) lithium preferably has a purity of at least 95%, more preferably at least 98%, and

in particular of at least 99%. As impurities example traces of other alkali metals, especially sodium, may be included.

Finally, the active material composition comprises at least one

Binder. This serves the remaining components of the

Active material composition together. In principle, any binder known to the person skilled in the art, in particular any polymeric binder, is suitable. Preferably, however, the at least one binder comprises at least one polymer selected from polyethylene oxide (PEO), a

Copolymer of polyethylene oxide, a Polymalonsäureester and / or a

Polyoxalic acid esters, in particular polyethylene oxide (PEO) and / or a copolymer of polyethylene oxide.

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 / b7 polystyrene block copolymer.

Polymalonic acid esters include repeat units of the general formula

with R ¹ , R ² = H or F;

R ³ = organic radical, in particular alkyl radical of the formula - (Chbjm-, where m is an integer from 1 to 10, preferably 2 to 8, and

n = 2 to 1000, in particular 10 to 500.

Polyoxalic acid esters include repeat units of the general formula

OD:

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 8; and

p = 2 to 1000, in particular 10 to 500.

In addition, the active material composition may also contain conductive additives such as carbon black, carbon nanotubes (CNT) and / or carbon fibers

(in particular vapor-grown carbon fibers (VGCF)) or ionic compounds, in particular lithium salts. Suitable lithium salts are in particular those which are also present in

Polymer electrolytes find use. These are explained below. The preferred amounts used correspond to those in

Polymeric amounts used.

In order to avoid a reaction of the elemental (metallic) lithium with solvents or any impurities contained therein, the

Active material composition produced substantially without the use of solvents. That is, no solvents are added during the preparation of the active material composition and the active material composition is substantially free of solvents, i.

less than 1 wt .-%, in particular less than 1 wt .-%, based on the

Total weight of the active material composition, comprising of solvents. Solvents in this case are liquid compounds at room temperature which are capable of at least partially dissolving the at least one binder. The essentially solvent-free production of

Active material composition is preferably done with the production method of the invention as more fully explained herein. This allows the substantially solvent-free production of a

Active material composition, in particular in the form of a freestanding active material composition film, which is subsequently applied to the

Current collector can be applied.

The invention also relates to the use of an electrode according to the invention in an electrochemical solid-state cell, in particular as a negative electrode in a solid-state electrochemical cell. Such

electrochemical solid-state cell, in addition to the invention

Electrode furthermore at least one solid electrolyte and at least one positive electrode.

The solid electrolyte is characterized in that it comprises or consists of a material which is substantially solid at room temperature and at least at operating temperature has sufficient ionic conductivity to ensure the transport of ions, in particular lithium ions, between the electrodes. In addition, the solid electrolyte is not electrically conductive. As a solid electrolyte can in principle all the

Professional known solid electrolytes such. As ceramic solid electrolytes and / or polymer electrolytes in the electrochemical invention Solid state cell can be used. In a preferred embodiment of the invention, the solid-state electrochemical cell comprises at least one polymer electrolyte. This preferably comprises at least one polymer and at least one conducting salt. Suitable polymers include polyalkylene oxides such as polyethylene oxide (PEO) and polypropylene oxide (PPO) and copolymers thereof. Preferably, the polymer comprises a polyethylene oxide (PEO) and / or a copolymer of polyethylene oxide. In a particularly preferred embodiment, the polymer of the polymer electrolyte is identical to the at least one binder of the negative electrode of the electrochemical solid-state cell according to the invention. Suitable conductive salts are in particular lithium salts. The conductive salt may for example be selected from the group consisting of lithium perchlorate (L1CIO4),

Lithium tetrafluoroborate (L1BF4), lithium hexafluorophosphate (LiPFe),

Lithium hexafluoroarsenate (LiAsFe), lithium trifluoromethanesulfonate (L1SO3CF3), lithium bis (trifluormethylsulphonyl) imide ((LiN S02CF ₃₎ 2),

Lithium bis (pentafluoroethylsulphonyl) imide (LiN (SO 2 C 2 F ₅ ) 2),

Lithium bis (oxalato) borate (LiBOB, LiB (C2C> 4) 2), lithium difluoro (oxalato) borate (LiBF 2 (C 2 C> 4)), lithium tris (pentafluoroethyl) trifluorophosphate (LiPF 3 (C 2 F ₅ ) 3) and combinations thereof. These can each be used individually or in combination with each other. Preferably, this makes at least one

Conducting salt a proportion of 1 to 5 wt .-%, in particular 2 to 3 wt .-% of the total weight of the polymer electrolyte.

As a positive electrode all known in the art

Electrodes are used, which are used as positive electrodes in

Electrochemical solid-state cells, especially in lithium-containing

electrochemical solid-state cells can be used. These usually comprise at least one current collector, as well as at least one

An active material composition disposed on and electrically connected to at least one surface of the at least one current collector. The current collector is made of an electrically conductive material and may otherwise be formed like the current collector of the negative electrode according to the invention. The active material composition comprises at least one active material and usually at least one

Binder. The positive active material usually includes compounds, which are able to reversibly take up and release lithium ions. Typical positive active materials are mixed oxides which comprise lithium and at least one metal selected from the group consisting of nickel, cobalt, manganese (so-called NCM mixed oxides). Examples include: L1C0O2, lithium-nickel-cobalt-aluminum oxides (eg LiNio.eCoo.isAlo.osCh;

NCA) and lithium nickel-manganese-cobalt oxides (z. B. LiNiO, 8Mno, ICOO, i0 ₂ (NMC (811)), LiNiO, 33Mn _0, 33Co _0, 330 ₂ (NMC (111)), LiNi ₀ , 6Mno, 2Coo, ₂ 0 ₂ (NMC (622)), LiNio, 5Mno, 3Coo, 20 ₂ (NMC (532)) or LiNio, 4Mno, 3Coo, 30 ₂ (NMC (433)), overlaid layer oxides of the general Formula n (U2MnO3) ^■ 1-n (L1 MO2) with M = Co, Ni, Mn, Cr and 0 <n <1, spinels of the general formula

n (Li ₂ MnO ₃ ) ^■ 1-n (LiM ₂ O) with M = Co, Ni, Mn, Cr and 0 <n <1. Furthermore, in particular spinel compounds of the formula LiM _x Mn 2- _x 0 ₄ with M = Ni , Co, Cu, Cr, Fe (eg LiMn20 ₄ , LiNio.5Mni.s0 ₄ ), olivine compounds of the formula LiM P0 ₄ where M = Mn, Ni, Co, Cu, Cr, Fe (eg LiFeP0, LiMnP0) , Silicate compounds of the formula Li ₂ MSiO with M = Ni, Co, Cu, Cr, Fe, Mn (eg Li ₂ FeSiO),

Tavorite compounds (eg LiVP0 ₄ F), Ü2Mn03, Li1.17Nio.17Coo.1Mno.56O2 and Ü3V2 (P0 ₄ ) 3 are highlighted as suitable positive active materials. Common positive electrode binders include styrene-butadiene copolymer (SBR), polyvinylidene fluoride (PVDF), polytetrafluoroethene (PTFE),

Carboxymethylcellulose (CMC), polyacrylic acid (PAA), polyvinyl alcohol (PVA) and ethylene-propylene-diene terpolymer (EPDM). Furthermore, the

Active material composition preferably still conductive additives, e.g. Conductive carbon black.

Furthermore, the solid-state electrochemical cell may optionally comprise at least one separator which is between the negative and the positive

Electrode is arranged. The purpose of the separator is to protect the electrodes from direct contact with each other, thus preventing a short circuit. At the same time, the separator must ensure the transfer of ions from one electrode to another. It is therefore important that the separator is electrically non-conductive, but has the highest possible ion conductivity, in particular with respect to lithium ions. Suitable materials are in particular polymers, such as polyolefins, polyesters and fluorinated polymers. Particularly preferred polymers are polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polytetrafluoroethene (PTFE) and Polyvinylidene fluoride (PVDF). Frequently, the solid electrolyte takes over the role of the separator, so that it is not necessary.

The invention also provides a process for solvent-free

Preparation of an active material composition which is elemental

(Metallic) lithium, in particular in the form of a free-standing active material composition film. The method comprises at least the following steps:

(i) providing at least one active material, in particular one

Graphite-containing active material,

(ii) providing elemental (metallic) lithium, especially in the form of particles, films, strips, wires, and / or pieces;

(Iii) providing at least one binder, in particular

selected from polyethylene oxide (PEO), a copolymer of

Polyethylene oxide, a Polymalonsäureester and / or a

Polyoxalsäureester;

(iv) preparing a homogeneous mixture of the at least one active material, the elemental (metallic) lithium and the at least one binder;

(v) introducing kinetic and / or thermal energy into the

homogeneous mixture to effect the formation of adhesive bonds between the at least one active material, the elemental (metallic) lithium and the at least one binder;

(vi) applying the resulting, optionally pasty mass

at least one substrate surface;

wherein none of steps (i) to (vi) use a solvent.

The previously made definitions and preferred embodiments for the active material, the elemental (metallic) lithium and the binder also apply correspondingly to the process according to the invention.

The process steps (i), (ii) and (iii) can be carried out separately or simultaneously. Likewise, the process steps (iv) and (v) can be carried out separately or at the same time. The elemental lithium is in a preferred embodiment of the

Invention in the form of lithium particles used in step (ii). However, it is also possible to use other shapes, e.g. Choose transparencies, strips, wires, and / or pieces. Due to the softness of the elemental lithium this can in the following process steps (iv) and / or (v) to

Be crushed lithium particles.

The at least one binder preferably comprises PEO and / or a copolymer of PEO. The at least one binder is preferably used in the form of particles, in particular in the form of particles having an average particle diameter of> 0.1 nm and <100 μηη, more preferably in a range of> 1 nm and <1 μηη, in particular in a range of> 10 nm and <100 nm. According to process step (iv), a homogeneous mixture of the at least one active material, the elemental lithium and the at least one binder is prepared. This can be done by any mixing method known to those skilled in the art, provided that this mixing method is suitable for the preparation of homogeneous mixtures of particles of said particle sizes. Suitable mixing devices are: mixer with movable

Mixing tools (e.g., screw mixers, paddle mixers,

Plowshare mixers), moving vessel mixers (e.g., drum mixers, cone mixers), pneumatic mixers (e.g., fluidized bed mixers,

Gas jet mixer), free fall mixer, shear mixer, litter mixer and / or centrifugal mixer.

According to process step (v), kinetic and / or thermal energy is introduced into the homogeneous mixture obtained in process step (iv). As a result, adhesive bonds are formed between the at least one active material, the elemental (metallic) lithium and the at least one binder. In a preferred

Embodiment, the at least one binder comprises at least one polymer selected from polyethylene oxide (PEO), a copolymer of

Polyethylene oxide, a Polymalonsäureester and / or a

Polyoxalsäureester. These polymers are characterized by being at Room temperature are comparatively soft, and have a low glass transition temperature and a low melting temperature. Binders are preferably used which have a glass transition temperature T _g of <20 ° C, in particular <10 ° C and / or a melting temperature T _m of <150 ° C, in particular <100 ° C. Particles of these binders can by the introduction of kinetic and / or thermal energy a

Form adhesive bond to the particles of the other components of the homogeneous mixture, as long as they collide with each other. In one embodiment of the invention, this adhesive bond is formed by subjecting the homogeneous mixture at least temporarily, i. for a period of at least 1 minute, preferably at least 5 minutes, to one

Temperature is heated, which is greater than or equal to the melting temperature of the at least one binder, while the homogeneous mixture is further, preferably continuously, mixed. As a mixing device for this purpose, one of the aforementioned mixing devices can be used. By introducing the thermal energy, a softening of the at least one binder, in particular on the surface of the binder particles, is thus at least partially achieved. In a collision of the binder particles with the active material and / or the lithium so adhesive bonds are formed.

The resulting active material composition is then cooled, preferably without further mixing. After cooling, a shapable, pasty, homogeneous active material composition is obtained. In an alternative embodiment of the invention, the adhesive bond is formed by a kinetic energy is at least briefly entered into the homogeneous mixture, which allows at least partial plasticization of the binder. This can be done, for example, by accelerating and selectively colliding the particulate constituents of the homogeneous mixture from process step (iv). In a preferred embodiment, the process step (v) is carried out in a jet mill or a ball mill. Particularly preferred is the use of a jet mill. This allows a speedy at least partially

Plastification of the binder without too much comminution of the

To reach active material particles. In return, elemental lithium, if it was not used in the form of particles but in the form of films, strips, wires, and / or pieces, due to the low hardness of lithium in this process step to particles are comminuted. This gives a moldable, pasty, homogeneous active material composition.

In an alternative embodiment, a homogeneous mixture of active material and elemental lithium is first prepared in step (iv), wherein the elemental lithium is optionally comminuted by appropriate (kinetic) energy input in step (iv) into particles into the mixture if necessary. Only then is the binder added and by further energy input in the form of kinetic and / or thermal energy, the formation of

Bonding achieved. This gives a shapable, pasty, homogeneous

Active material composition. In a preferred embodiment, the method steps (iv) and (v) are carried out in the same mixing device, in particular in a jet mill. This allows a reduction in the number of process steps. Preferably, in this case, mixing of the components at low energy input, i. be carried out at low power of the jet mill. Subsequently, the formation of the adhesive joints in a performance of

Jet mill instead, which allows at least a partial plasticization of at least one binder. Alternatively, the at least one active material and the lithium can first be mixed alone in a jet mill and, if necessary, comminuted. Subsequently, the binder is added and the formation of the adhesive bonds takes place.

The moldable, pasty, homogeneous active material composition is then in a further process step (vi) to a

Substrate surface applied. The substrate surface in the sense of this invention, in particular the surface of a tool, the surface of a

Support material (e.g., a plastic film) or the surface of a

Be a current collector.

In one embodiment, the substrate surface is the surface of a tool, eg, the surface of a treadmill. This is preferably made of plastic. The

Active material composition can in this case at the end of the

Production process can be removed as a free-standing active material composition film. This may then be detached from the substrate surface and applied to a current collector, e.g. at a temperature above the

Glass transition temperature T _{g of} the binder to be laminated.

In a preferred embodiment of the invention, the substrate surface is the surface of a current collector. In this case, no free-standing active material film is produced, but an electrode is obtained.

In a further alternative embodiment, the method steps (v) and (vi) are carried out together in a calender. The homogeneous mixture of active material and elemental lithium prepared in step (iv) is added to the calender, processed by additions of thermal and kinetic energy to a homogeneous, preferably moldable (pasty) mass and applied to a substrate surface. This can be done by a pressing process, a calendering process or a combination thereof. This gives a freestanding active material composition.

Subsequently, the active material layer, preferably at a temperature above the glass transition temperature T _{g of} the at least one

Binder is compacted by a press, a punch or a roller. The densification step may additionally be carried out under the action of heat in order to prevent the binder from adhering to the surface of the substrate

Support current collector and cause a permanent consolidation. If the substrate surface is not the current collector, preferably no heat is supplied.

Preferably, each of the method steps of the invention

Process in which elemental lithium is present or used is carried out with the exclusion of water or other acidic compounds, in particular under a dried gas atmosphere, in particular

Inertgasatmosphäre such as dried argon or nitrogen atmosphere. By the method according to the invention it is possible to produce an electrode without the use of a solvent. The obtained electrode is substantially free of solvents.

The invention also provides the use of the method according to the invention for producing an active material composition film for an electrode according to the invention. The electrode according to the invention and the electrochemical solid-state cell according to the invention find advantageous 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.

Advantages of the invention

The electrode according to the invention makes it possible to introduce additional elemental lithium into an electrochemical cell, which can compensate for the loss of lithium in the electrochemical cell which occurs as a result of the formation of a solid electrolyte interphase. The invention

In addition, by eliminating solvents, the production process also makes it possible to minimize the occurrence of side reactions of the lithium with the solvent and any impurities contained therein and the associated loss of elemental lithium in the active material composition of the electrode.

Brief description of the drawings

It shows:

Figure 1 is a schematic representation of an inventive

electrochemical cell.

Embodiments of the invention In Figure 1, the structure of a solid-state electrochemical cell 1 is shown schematically. A negative electrode 21 comprising a current collector 31 and an active material composition 41 is connected to the negative terminal 11 via the current collector 31. Opposite there is a positive electrode 22, which also comprises an active material composition 42 and a current collector 32, via which the positive electrode 22 is connected to the positive terminal 12 for discharge. The negative electrode 21 and the positive electrode 22 are disposed in a cell case 2. The solid electrolyte 15 mechanically separates the negative electrode 21 and the positive electrode 22 from each other and simultaneously makes an ion conductive bond between the negative electrode 21 and the positive electrode 22. The solid electrolyte 15 thus also assumes the role of the separator.

The active material composition 41 of the negative electrode 21 includes, for example, graphite as the active material, elemental lithium, and

Polyethylene oxide as a binder. Preferably, the polyethylene oxide additionally comprises a conductive additive, for example Li (CF ₃ ) SO ₂ NSO ₂ (CF ₃ ) (LiTFSI). The current collector 31 is preferably made of a metal, for example of copper.

The active material composition 42 of the positive electrode 22 includes, for example, an N-CM mixed oxide as an active material and further at least one binder such as a binder. Carboxymethylcellulose (CMC), as well as a conductive additive, e.g. Conductive carbon black. The current collector 32 is preferably made of a metal, e.g. made of aluminium.

As the solid electrolyte 15, a polymer electrolyte, for example, a mixture of polyethylene oxide and Li (CF ₃ ) SO ₂ NSO ₂ (CF ₃ ) (LiTFSI) is used.

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.

Claims

claims

An electrode for an electrochemical cell, comprising at least one current collector and at least one active material composition, wherein the active material composition comprises at least one active material, elemental lithium and at least one binder and was prepared without the use of solvents.

The electrode of claim 1, wherein the at least one active material comprises graphite.

3. An electrode according to claim 1 or 2, wherein the at least one

Binder is a polymer selected from polyethylene oxide (PEO), a copolymer of polyethylene oxide, a Polymalonsäureester and / or a polyoxalic acid ester.

4. An electrode according to any one of claims 1 to 3, wherein the

Active material composition in the form of a freestanding

Active material composition film is provided.

5. Use of an electrode according to one of claims 1 to 4 as a negative electrode (21) in a solid-state electrochemical cell (1).

6. Electrochemical solid-state cell (1) comprising at least one

A solid electrolyte (15), at least one positive electrode (22) and at least one negative electrode (21), wherein the at least one negative electrode (21) is an electrode according to any one of claims 1 to 4.

7. Electrochemical solid state cell (1) according to claim 6, wherein the

at least one solid electrolyte (15) comprises polyethylene oxide (PEO) and / or a copolymer of polyethylene oxide. Process for the solvent-free production of a

Active material composition comprising elemental lithium, in particular in the form of a free-standing

Active material composition film comprising at least the following process steps:

(i) providing at least one active material,

(ii) providing elemental lithium;

(iii) providing at least one binder, in particular selected from polyethylene oxide (PEO), a copolymer of polyethylene oxide, a polymalonic acid ester and / or a polyoxalic acid ester;

(iv) preparing a homogeneous mixture of the at least one active material, the elemental lithium and the at least one binder;

(v) introducing kinetic energy into the homogeneous mixture to effect the formation of adhesive bonds between the at least one active material, the elemental lithium and the at least one binder;

(vi) applying the resulting composition to at least one

Substrate surface;

wherein none of steps (i) to (vi) use a solvent.

The method of claim 8, wherein the substrate surface is the

Surface of a current collector is.

Use of the method according to claim 8 or 9 for producing an active material composition film for an electrode according to any one of claims 1 to 4.