DE102016124586A1 - Electrode material, process for producing electrodes and these electrodes and electrochemical cells - Google Patents

Abstract

In a first aspect, the present invention is directed to an electrode material, which is in the form of a colloidal solution of a molecular complex of nanoscale redox-active organic oligomer and / or polymer and at least nanoscale graphitic material. In addition, a method for the production of electrodes is provided, as well as corresponding electrodes. Furthermore, the present invention relates to electrochemical cells with electrodes according to the invention and / or electrode material according to the invention. Finally, a process for the preparation of redox-active organic oligomers and / or polymers is described.

Description

In a first aspect, the present invention is directed to an electrode material, which is in the form of a colloidal solution of a molecular complex of nanoscale redox-active organic oligomer and / or polymer and at least nanoscale graphitic material. In addition, a method for the production of electrodes is provided, as well as corresponding electrodes. Furthermore, the present invention relates to electrochemical cells with electrodes according to the invention and / or electrode material according to the invention. Finally, a process for the preparation of redox-active organic oligomers and / or polymers is described.

State of the art

Mobility and information exchange are increasingly shaping the life of modern society. Therefore, more and more efficient, rechargeable, portable batteries and accumulators are inevitably needed. High gravimetric and / or volumetric energy and / or power density and stability over many charge / discharge cycles are required. By way of example, it is expected that a smartphone will run for several days without having to recharge it, that is to say a high volumetric and gravimetric energy density of the accumulator. The battery pack of an electric car should guarantee a range of at least 500 kilometers, this requires a high energy and power density and the battery should also be fast, such as in a few minutes, rechargeable, which requires a high power density. For example, to keep a drone in flight for more than an hour, the cells used, ie the batteries / accumulators, require a high power and energy density.

Moreover, in the future, the external shape of the battery should be able to be adapted to given external shapes, for example be woven or incorporated into fabrics of clothing, or be integrated into the bracelet of a smartwatch or the like. That is, a flexibility of the batteries is provided. In addition to energy and power density, recyclability, degradability, for example by composting, but also a reduction in the toxicity, in the present case of heavy metal content, and an expression reliability play an increasingly important role, especially in the case of large production numbers.

There are a variety of batteries / accumulators based on different principles. In the present case, the terms batteries and accumulators are used synonymously, unless stated otherwise.

In principle, all anode / cathode systems are subsumed under the term LIBs (Lithium Ion Batteries) with two surface-anchored lithium ion intercalation systems. Usually, this term is understood to mean the lithium ion batteries on the market. These dominate the accumulator market because of their high energy density, their high Zyklisierbarkeit and their relatively high friendly handling in various variations. The standard anode of such LIBs is based on a (de) intercalation of Li ⁺ in graphite corresponding to a potential that practically corresponds to the potential of the Li ⁺ / lithium half-cell. As a result, it has a negative potential of about -3V against a SHE (standard hydrogen electrode), the gravimetric capacity is about 350 mAh / g and the average volumetric capacity is between 330 to 430 mAh / cm ³ . The area-specific capacity is between 3 to 4 mAh / cm ² , thereby making it an ideal anode material.

The cathode in such a system is based on the reversible (de) intercalation of lithium ions in crystalline metal oxides and phosphates. Here is currently the most improvement potential seen. We are looking for materials with high volume-, mass-specific and area-specific energy and power density. Conventionally, materials of the LiMO ₂ type have hitherto been used, with M being nickel, cobalt and / or manganese. These deliver capacities of around 180 mAh / g, recently describing a vanadium oxide cathode capable of up to 400 mAh / g, but exhibiting variable discharge voltage and poor cyclability.

In general, these lithium ion batteries with a graphite anode and a LiMO ₂ cathode cell voltage of> 3V, but this undesirable side reactions and a considerable hazard potential (explosion safety) occur. Among other things, a decomposition of the combustible organic solvent is observed, the Zyklisierbarkeit and charge capacity is deteriorated.

A large area specific charge (current density) in such LIB cathode materials is limited by the low ion and electrode conductivity in the intercalation grid and between the crystals. This limitation and overcoming of this is currently the subject of intensive research into the To circumvent diffusion of lithium ions and electrons in and out of the cathodic host crystal, for example, small crystals are used, the synthesis of which, however, is expensive. To improve the ion and electrode conductivity between the host crystals, graphitic micro- and nanomaterials are added. Compressing these nano- and microcomponents, that is the host crystals and graphitic material in the presence of binders, results in a porous composite material with electrolyte and electrode percolation system, but this does not result in molecular contact between the electrical conductor and the charge storage material, so that sufficient Connection between the different components takes place.

Such systems are usually in a ratio of active material: electrode conductor: binder in percent by weight of a maximum of 75:50:10 ago. Although the addition of graphitic material increases the specific current density (mA / cm ² ), the surface and area-specific capacitance (mAh / gcm ² ) is lower than its own weight. Solving this problem of conflicting requirements is the subject of much research. Typical values for such systems are, for example, energy densities of 150 to 100 mA / g, with a maximum layer thickness of approximately 100 μm, with approximately 1 to 4 mAh / cm ² at maximum current densities of 5 to 8 mA / cm ² .

For example, in the WO 2014/093876 A1 described a semisolid electrode material with a high capacity, the cathodic materials have layer thicknesses up to several 100 microns, it could have specific capacities of up to 12 mA / cm ² and current densities up to 10 mA / cm ² without loss of capacity and up to 16 mA / cm ² with a 50 percent capacity loss.

The LIBs based on aqueous systems, however, have the problem that they can not afford high cell voltages, that is, aqueous electrolytes can not be used in the above-mentioned lithium ion batteries due to the evolution of hydrogen and oxygen and the resulting possible explosion potential, but rather Organic solvents are necessary, but have other disadvantages, such as a high flammability.

Corresponding problems often occur with lithium anodes. Although alternative anode materials are compatible with aqueous electrolytes (for example, TiO ₂ ), they did not have sufficient capacity and an insufficient charge / discharge cycle number to reduce the cell voltage.

As already stated, flexibility in batteries is also desirable. However, there is no flexibility in crystalline material due to the cathodes used by the LIBs. The use of thin layers of host crystals on a flexible current collector attempts to produce flexible batteries, but these have limited performance characteristics.

Crystalline ceramic cathode systems, that is to say those based on oxides and phosphates in known LIB systems, are poorly suited for flexible, bendable or stretchable batteries, although some embodiments have already been proposed. In principle, the inorganic-ceramic intercalation host systems are brittle and flexibility can only be achieved by using small host crystals with admixture of a flexible binder and / or conductor polymer, but this significantly reduces the energy and power density of the battery material.

Organic and organometallic redox polymers are widely referred to in the literature as potentially active battery materials; However, their potential as active battery materials has not yet been exhausted. In particular, it has not been possible to come close to the performance characteristics of the established lithium batteries. Corresponding redox polymer electrodes and redox polymer electrochemical cells may be used as cathodes instead of lithium graphite anodes and / or inorganic ion intercalation systems.

All kinds of combinations between these two systems are possible.

However, it has not yet been possible to achieve the desired, economically interesting surface-specific charge densities (mAh / cm ² ) and area-specific maximum current (mA / cm ² ) with redox polymer materials. The reason for this is the insufficient ion and / or electron Perkolationsverhalten of the redox polymer material, a problem, which could not be overcome so far.

Various approaches have already been described in the literature, inter alia, in which polymeric aromatic boron and sulfur compounds or polymeric N-oxides are used. Farther there are poliologists / PolitTEMPObatterien (TEMPO = 2,2,6,6-tetramethylpiperidin-1-yl) oxyl) with PolyTEMPOschichten to 3 microns and linear scalable surface specific capacity up to about 120 mA / cm ² , this were at a small layer thickness of 100 nm and capacities of about 2.8 mC / cm ² (corresponding to 0.001 mAh / cm ² ) charge / discharge cycles of 60 C / cm ² possible. However, the current technique of fast charging and discharging cycles, that is to say those with a specific charging speed (C / cm ² )> 10, allows redox polymer modified electrodes to have a maximum formation of 100 monolayers so that the necessary specific capacities are not achieved. Advantages of organic redox polymer cathodes over the conventional based on inorganic transition metals are their environmental friendliness, since the organic redox system is biodegradable, they can also be flexibly equipped as well as the possible synthesis of the arbitrary determination of the reduction potential.

Generally, during charging / discharging, electron currents flow in / out of the final current collector and ion currents flow from / into the electrolyte phase into the battery material. The local electron currents in the active layer material grow in the direction of the final current collector, while the ion currents rise in the direction of the bulk electrolyte. Ideally, the cross sections of the electron and ion current conductors in the battery material layer should be adapted to the locally expected maximum currents in order to be able to conduct currents over a large current density range without resistance at high energy density. From Magasinski (Maginski, A. et al; Nature Materials, 2010, 9 (4), 353-358) For example, in the case of a lithium ion anode, it has already been speculated that efficient electron percolation through the battery material at the nanometer and micro to macro scales can well be accomplished only by a hierarchical percolation system.

Such hierarchical electron and ion conductor networks support electron and / or ion percolation at the molecular, nanoscopic, microscopic and macroscopic level. For example, micrometer-sized graphene-encapsulated Si particles are described that achieve 3.2 mA / cm ² , and SiC particles deposited on carbon black are also used, which are then converted into granular structures by self-assembly. As a result, five times higher specific capacities are achieved.

In order to avoid a current- or capacity-limited situation, efficient electron as well as ion percolation must be optimized simultaneously. However, an implementation thereof for organic redox polymers is not described in the literature.

In addition to the above-mentioned problems of sufficient charge capacity, etc., environmental and safety aspects continue to play a major role. The recycling of inorganic battery materials, such as metal oxide cathodes, is complex and even more expensive than that of lead-acid batteries. Furthermore, LIBs can heat up and burn off in the event of an internal or external short circuit, with flammable organic solvents / electrolytes playing an important role. Examples of fires in vehicles are known. Notorious is the exploding of lithium batteries with high cell voltage in case of internal short circuit. For this reason, for example, it is not possible to send small lithium batteries by means of simple air mail, it is necessary security containers.

The required cell voltages, for example, with LIBs with graphite anode and a LiMO ₂ cathode of up to 3.5 V require the use of non-aqueous electrolyte, since in water a thermodynamic decomposition voltage is 1.24 V. Although organic solvents / electrolytes can be used for higher cell voltage, they are often combustible. To overcome this problem, activation barriers have been designed which allow an increase in cell delivery to as high as 1.6V to employ aqueous electrolytes, but do not achieve the desired cell voltages of three and more volts.

The use of inorganic intercalation systems is not compatible at the molecular-nanoscopic level with a design of flexible, d. H. bendable and stretchable accumulators as they are increasingly demanded by the economy, eg. Smart watches and apparel industry. Even grinding of corresponding materials with subsequent crosslinking does not permit large area-specific current densities with a large area-specific capacity. In addition, the use of heavy metals, d. H. from Z. B. 3-D transition metals, as used today in LIBs, the cathode material for environmental reasons of concern, previous redox oligomer or polymer systems do not allow large area-specific current densities at large capacity.

Description of the invention

The aim of the present invention is to provide novel electrode materials based on redox-active organic oligomers and / or polymers and graphitic material, this Electrode material is particularly useful for providing nanoscopic and microscopic level inventive percolation systems that provide improved area-specific current densities at high capacitance and thickness scalability.

Surprisingly, it was found that the bad volumetric energy density hitherto assumed when using redox polymer is in fact not given by the electrode material according to the invention and the electrodes according to the invention, but the materials and electrodes according to the invention show a good volumetric energy density.

By using the electrode material according to the invention, several 100 μm thick layers can be built up on corresponding current collectors for the formation of electrodes in order to obtain corresponding electrodes of the next larger hierarchy. In this case, the electrode material according to an embodiment of the present invention is selected so that the potential between-1 volt and plus 1 volt is freely selectable. Because of the size-thickness scalability of the electrode material, hierarchically larger current collectors can be easily connected to the electrode material. As a result, previously unachieved specific charge and current densities can be realized with organic batteries. In addition, the electrode materials with the redox-active organic oligomer and / or polymer do not receive heavy metals, they can be operated with aqueous electrodes and / or organic electrodes and are essentially biodegradable. These redox-active organic oligomers and / or polymers (hereinafter also referred to as redox polymers) also allow the formation of flexible, d. H. bendable and stretchable batteries.

In a first aspect, therefore, an electrode material in the form of a colloidal solution of a molecular complex comprising at least one maximum nanoscale redox-active organic oligomer and / or polymer and at least one nanoscale graphitic material, wherein these in a weight ratio of redox-active oligomer and / or polymer and graphitic material is from 1: 1 to 20: 1 and wherein the redox-like organic oligomer and / or polymer forms a complex with the graphitic material provided. In one embodiment, an addition of 1 to 10 weight percent, e.g. B. 3-7 wt.%, How 4-6 wt.%, Based on the redox polymer used, a pore-forming agent, such as polyvinylidene fluoride, carried out in order to increase the Zyklisierbarkeit and reversibility of the material. The skilled person is aware of suitable pore formers.

This electrode material in the form of a colloidal solution permits the production of electrodes on corresponding current collectors having the properties desired according to the invention; in this case, corresponding hierarchical structures with 2 or 3 hierarchical generations can be formed. The electrodes with the corresponding current collectors and the electrode material according to the invention have, at least in the hierarchies, a nanoscopic hierarchy (Hierarchy III), possibly a microscopic hierarchy (II) and furthermore a macroscopic hierarchy (Hierarchy I). The redox-active organic oligomer and / or polymer forms a complex with the graphitic nanoscale material of hierarchy III.

In the electrode material according to the invention, the weight ratio of the redox-active oligomer and / or polymer and graphitic material is in a range from 1: 1 to 20: 1. In one embodiment, the weight ratio is in the range of 2: 1 to 10: 1. The redox-active oligomer and / or polymer and graphitic material, both of which are nanoscale, may be one with a polycationic charge carrier of the oligomer and / or polymer and negatively charged graphene oxide.

In order for the complexation of the graphene oxide to take place completely, the zeta potential of the colloid should be inverted from negative to clearly positive, so that a stable colloidal solution can be achieved. In one embodiment, the minimum weight ratio is from 2: 1 to 3: 1.

When providing an electrode material for the production of batteries with a possible optimization for high current density, the weight ratio of redox-active oligomer and / or polymer, graphitic material is preferably in a range of 3: 1 to 5: 1.

In an electrode material for producing battery material with optimized high capacity density, the weight ratio is preferably in a range of 5: 1 to 10: 1. When manufacturing the electrode material for batteries, paying attention to a high current and capacity density, the weight ratio is 3: 1 to 6: 1.

With large layer thicknesses of, for example,> 10 .mu.m, rather smaller weight ratio ranges should be used, while with smaller layer thicknesses of, for example, <1 .mu.m, weight ratios in the higher ratio range are used.

In one embodiment, the oligomers or polymers which are, for example, partially formed as dendrimers are present in the formed complex in polycationic form. It is believed that this charge is due to either the charge of the polymer in the existing oxidation state, or by complete or partial oxidation of the polymer prior to complex formation or by synthesis in the polymer chain of the oligomer and / or polymer.

In one embodiment, the colloidal solution is present in a solvent such as water or aqueous solvents.

In one embodiment according to the invention, the electrode material according to the invention does not contain any heavy metals and / or heavy metal ions.

In one embodiment, the oligomers and / or polymers may be present at least partially as dendrimers.

In one embodiment of the electrode material according to the invention, the redox-active organic oligomer and / or polymer has at least two electrophorus groups of predominantly cathodic character from the classes of electrophorus groups of aliphatic or aromatic N-oxides, 9-alkyl and aryl-carbazoles, 1,4-diisocyanates. Alkyloxy and aryloxy-2,5-tert-butylbenzenes, benzoquinone diimines, N-alkyl-phenothiazines, or at least two predominantly anodic electrophorus groups selected from the classes of electrophore groups derived from bipyridinium salts, quinones, anthachinones or aromatic 1,4 or 1 , 2 dioxo compounds, aromatic tetracarboxylic diimides, aromatic dicarboxylic acid salts, benzylic or aromatic disulfides.

The mentioned electrophoretic groups can carry a plurality of electronically reducible subunits, which complement each other to form a 2-electronically reducible subunit. An example is the bipyridinium, which has two electronically reducible subunits.

N,N'-Dimethyl-4,4'-Bipyridinium

N,N'-Dimethyl-2,2'-Bipyridinium

Anthrachinon

Phenamthren-9, 10-dion

N,N'Dimethyl-Py-romellitdiimid

Li Terephthalat

Dihydrotetrathiaanthracen

(2,2,6,6-Tetramethylpiperidin-1-yl)oxyl

Galvinoxyl

9-Methylcarbazole

1,4-Di-t-Butyl-2,5-dimethoxybenzol

N,N'-2,5-cyclohexadiene-1,4-diylidenebis

n-methyl phenothiazine In a further embodiment, the electrode material is one in which these oligomers and / or polymers have multiple, localized or conjugated, reversibly oxidizable / reducible electrophors, in particular having at least two electrophore groups selected from the following electrophoretic groups:

N, N'-dimethyl-4,4'-bipyridinium

N, N'-dimethyl-2,2'-bipyridinium

anthraquinone

Phenythrene-9, 10-dione

N, N'Dimethyl-Py-romellitdiimid

Li terephthalate

Dihydrotetrathiaanthracen

(2,2,6,6-tetramethylpiperidin-1-yl) oxyl

galvinoxyl

9-Methylcarbazole

1,4-di-t-butyl-2,5-dimethoxybenzene

N, N'-2,5-cyclohexadiene-1,4-diylidenebis

n-methyl phenothiazines

It was found that the electrode material according to the invention improves the formation of the hierarchies and the linking of these hierarchies with one another.

The electrode material according to the invention is in particular a biodegradable electrode material.

In one embodiment, the electrode material according to the invention is one with graphene oxide and a redox-active oligomer and / or polymer based on N, N'-dimethyl-4,4'-bipyridinium.

In a further aspect, the present invention is directed to a method for producing an electrode with an electrode material according to the invention. This method comprises applying the electrode material in the form of a colloidal solution to a current collector; Subsequently, the solvent in which the said components are present, while maintaining the molecular complex structure of the electrode material of the graphitic material and the redox-active organic oligomer and / or polymer on the current collector removed.

In a further aspect, the electrode manufacturing method of the invention comprises the step of converting the graphitic material in the form of a graphene oxide by chemical reduction, in particular by electrochemical reduction, such as by electrocatalytic reduction to reduced graphene oxide.

By converting the graphene oxide into reduced graphene oxide, it is possible that this reduced graphene oxide has graphene-like properties and thus is well suited as an electrode material.

Those skilled in the art are well-known methods for reducing graphene oxide to reduced graphene oxide (rGO). Thus, this activation of the electrode material can be carried out by reduction electrochemically. This is z. B. the corresponding electrode after application of the electrode material several times cyclically scanned to the range of -1.1 V (against Ag / AgCl). For example, as the electrocatalyst, the polymer itself is active when it is reducible more negatively than -0.5 V in the potential range, or monomeric viologen is added to the electrolyte, which then takes on the role of the electrocatalyst. The appropriate scan speed can be adapted to the thickness of the layer. The reduction of graphene oxide to reduced graphene oxide is seen by a cathodic catalytic stream in the range of more negative than -0.3 V, after decrease or disappearance of the electrocatalytic stream, the conversion to reduced graphene oxide is completed.

In a further aspect, the present invention is directed to an electrode with an electrode material according to the invention and a current collector, this current collector is formed at least microscale.

Herein, the term "nanoscale" means materials which are smaller than 500 nm in the smallest dimension, in particular materials smaller than 200 nm in their smallest dimension, such as smaller than 100 nm, for example smaller than 50 nm, smaller than 10 nm are the term micro-scale materials that are in their smallest dimension between 500 nm and 100 μm, and the term macro-scale to materials that are greater than 100 μm in all dimensions.

The final macroscopic current collector is, for example, an electrically conductive, possibly flexible plate. The microscopic current collector is typically one embodiment of carbon fibers, such as a felt or nonwoven fabric, or in the form of a fabric, or in the form of a foam such as a 3D carbon foam carrier material, wherein at least one dimension of the structure is in the range of 500 nm and 100 μm. The microscopic current collector may further consist of an ensemble of VGCFs (vapor grown carbon fibers).

Based on the hierarchical system described herein, the current collectors are those of the hierarchy III, such as graphene oxide or conductive single-wall carbon nanotubes (SW-CNTs) or multiwall carbon nanotubes (CNTs) or vapor-grown carbon nanofibers (VGCNFs) Zeta potentials.

Suitable current collectors of the hierarchy II are the mentioned carbon fibers in the form of felt or fleece, for example those with fibers in the thickness range of approximately 5 to 30 μm or VGCF in the thickness range of> 200 nm.

In one embodiment, the layer thicknesses of the various components of the individual hierarchies are adjusted to be compatible with the other hierarchies. For example, the thickness of the hierarchy I layer is preferably selected to be similar to the thickness of the fiber diameter or pore diameter of the Hierarchy II current collectors, so that after receipt there is still a percolating ionic conduction system of Hierarchy II. Suitable Hierarchy I Current collectors are molecularly flat carbon sheets or plates in the thickness range of 10 μm to 1 cm.

1. a) Mehrfache (serielle) Applikation/Lösungsmittelentzug (wie beschrieben in Beispiel 1
2. b) Kontinuierliche Applikation der kolloidalenLösung mittels Spritze auf den ständig geheizten Stromkollektor
3. c) air brush Applikation der kolloidalen Lösung auf den geheizten Stromkollektor
4. d) Elektrophoretische Belegung des Stromkollektors. Zur Verwendung kommt die im Verhältnis 3:1 (Polymer/Graphenoxid) hergestellte Lösung

The electrodes can be produced by known methods, for example, the occupation of the current collector of the hierarchy I can be carried out with he colloidal solution of the electrode material according to the invention such that thick homogeneous hierarchy III / I electrodes arise. Suitable methods for coating the micro- or macroscopic current collector with the colloidal solution include:

1. a) Multiple (serial) application / solvent removal (as described in Example 1
2. b) Continuous application of the colloidal solution by syringe to the constantly heated current collector
3. c) air brush application of the colloidal solution to the heated current collector
4. d) Electrophoretic assignment of the current collector. For use comes in the ratio 3: 1 (polymer / graphene oxide) prepared solution

Methods a) -d) provide similar performance but are well suited for industrial applications.

In the case of a combination of all three hierarchies in the electrode, the layer thickness of the hierarchy III should also be adjusted as homogeneously as possible, but additionally in the fiber or pore size of the collector of the hierarchy II. The preparation of such an electrode with a Hierarch III electrode material and a Hierarchy II fibrous current collector can be accomplished by repetitive immersion / annealing of the fibrous electrode with the colloid.

When using graphene oxide, the production of the electrode takes place first, then the conversion of the graphene oxide into reduced graphene oxide takes place.

As stated above, this includes an electrocatalytic method using self-catalysis, preferably the redox-active oligomer and / or polymer of one with E ⁰ <-0.3 V. In another embodiment, it is an electrocatalytic method and using a redox mediator with E ⁰ <- 0.3 V. Such a method is to be used in particular if self-catalysis is not possible. Alternatively, an electrochemical conversion or the simple thermal However, such a thermal method is suitable only for a few inventive redox-active oligomers and / or polymers, such as polyimides, since otherwise destruction of these can take place.

In one embodiment, the electrode is designed as a flexible electrode. The current collector is selected accordingly to form a flexible electrode. In particular, this flexible electrode is one using a carbon film as a current collector and an electrode material having reduced graphene oxide or graphene as a graphitic material.

Furthermore, the present invention is directed to an electrochemical cell having a cathode and an anode, wherein an electrode material according to the invention and / or an electrode according to the invention forms at least one of the cathode or anode.

The electrochemical cells can be present in various combinations. This means that on the one hand one of the electrodes can be present with an electrode material according to the invention, while the second electrode is a conventional material or both electrodes can be made of the electrode material according to the invention.

1. 1. Redoxpolymeranode/traditionelle Übergangsmetall(phosphat)kathode oder
2. 2. Traditionelle Li(Li-Graphit)anode/Redoxpolymerkathode oder
3. 3. Redoxpolymeranode/Redoxpolymerkathode.

In principle, the following combination options are available:

1. 1. Redox polymer anode / traditional transition metal (phosphate) cathode or
2. 2. Traditional Li (Li-graphite) anode / redox polymer cathode or
3. 3. Redox polymer anode / redox polymer cathode.

One embodiment thus comprises an electrochemical cell, where the cathode and the anode comprise an electrode material according to the invention. In a further embodiment, the electrochemical cell is a flexibly configured cell. In one embodiment, this is an electrochemical cell with an organic electrolyte, this in one embodiment, cell voltages of ≥ 1.5 V, such as ≥ 2 V on.

In a further embodiment, it is an electrochemical cell, which has a surface-specific capacity of ≥ 20 mAh / cm ² with a total thickness of the electrochemical cell of ≦ 1 cm.

The invention is characterized in that, because of the excellent thickness scalability of the electrode material of the third hierarchy, the next higher hierarchies, namely the hierarchy II and the hierarchy I, can be connected to the hierarchy III in terms of capacitance and current density substantially without any loss. As a result, the electrochemical cells according to the invention, for example based on the redox-active organic oligomers and / or polymers, achieve performance values which have hitherto only been achieved by heavy metals containing LIBs. The electrode material according to the present invention is scalable in the range of 100 nm to 2 mm.

In a suitable embodiment, these are electrodes and electrochemical cells having such electrodes, wherein the current collector is one of the next larger hierarchy II, for example a three-dimensional current collector based on a foam or based on a carbon fiber fleece. Suitable fibers are, for example, the 1D graphite fibers of a carbon felt, the fibers of a carbon nonwoven consist of fibers in the thickness range of approximately 5 to 20 μm or VGCFs with a diameter of> 500 nm. For dense fibers or spaced-apart fibers, the intermediate regions can be covered with the electrode material according to the invention, This creates an optimal solvent and electrode percolating system of two hierarchical generations. This will be further explained below. This allows surface-specific capacities of 21 mA / cm ^{2 to be} achieved. In addition, the electrochemical cells are those that are compostable, that is, have the biodegradable materials.

The electrochemical cells according to the invention are particularly suitable as batteries / accumulators in the vehicle sector. Another particularly suitable application is the use as flexible electrochemical cells, for example in the field of clothing or smartwatches, etc.

The electrochemical cells may also have aqueous electrolytes, this represents in particular environmentally friendly batteries.

• - Bereitstellens eines 1,1-(2,4-Dinitrophenyl)-4,4-Bipyridiniumdichlorids und einer zweiten Einheit umfassend mindestens zwei Aminogruppen;
• - Umsetzen dieser beiden Verbindungen unter Freisetzung von einem 2,4-Dinitroanilins unter Erhalt einer oligomeren oder polymeren Viologengruppen aufweisenden Verbindung.

Finally, the present invention provides a process for preparing a viologen-group-containing oligomer or polymer. This procedure includes the steps

• - Providing a 1,1- (2,4-dinitrophenyl) -4,4-Bipyridiniumdichlorids and a second unit comprising at least two amino groups;
• - Reacting these two compounds to release a 2,4-dinitroaniline to give an oligomeric or polymeric viologen-containing compound.

In one embodiment, the reaction takes place after a Zincke reaction.

The invention will now be further explained with reference to the figures and to the examples.

The invention relates to the production and use of a hierarchical conductor system with 2 or 3 Hierarchiegenerationen, for organic, oligomeric or polymeric, rigid or flexible battery materials, the hierarchies necessarily the nanoscopic (Hierarchy III), possibly the microscopic (II) and necessarily the macroscopic Range (hierarchy I) include ( and ). The conductor material preferably consists of graphene oxide / graphene but can also consist of conductive CNTs (carbon nanotubes), multiwall CNTs, or VGCNFs (vapor grown carbon nanofibers). The hierarchical electron conductor system is paired with a nanoscopic, preferably also hierarchically constructed ion guide system. For the preparation of the nanoscale Generation III composite, the molecular self-assembly of oligomeric, dendritic or polymeric organic or organometallic, especially multi-cationic compounds or salts on the nanoscopic conductive or latent conductive, nanoscale, advantageously negatively charged current collectors is used. This technique makes it possible for the first time to produce anodic or cathodic redox polymer battery composites of hierarchy III with thicknesses down to submicrons down to the mm range, without much sacrifice in area-specific capacitance and current density. Thus, the composite surpasses corresponding redox polymers without the nanoscopic nanoscopic conductor system by a factor of 10 to 1000 in terms of current density and capacitance.

Hierarchy III, self-assembly:

The production of the hierarchy III nanoscopic current conductor / ion conductor / redox polymer system is based on the self-assembly of oligomeric, dendritic or polymeric organic or organometallic, in particular multi-cationic compounds or salts (the polycationic reversible charge carriers) on nanoscopic conductive or latent conductive, preferably multiple negative charged, graphitic materials such as graphene oxide, partially oxidized, conductive carbon nanotubes or carbon fibers (VGCNFs). In principle, it is possible to use all known oligomeric or polymerizable organic or organometallic, reversible redox systems as charge carrier components. Particularly suitable are polycationic charge carriers that undergo electrostatically driven self-assembly with the nanoscale current collector systems. The preparation of the polycationic charge carriers is in described. In principle, systems with the redox-active component (RA) in side chains (IIX) or in the main chain (IX) are suitable. The positive charge is either naturally present in the stable state, or must be caused by partial oxidation of the charge carrier prior to self-assembly, or it must be synthetically introduced by linking to a persistent positive group (PC ⁺ ). In certain cases (in extended π systems, eg in aromatic polyimides), the π interaction already suffices to form the self-assembly of reversible charge carriers and nanoscopic current collectors. In this case, preferably a phase transfer reaction between aqueous-colloidal solution of graphene oxide and a homogeneous solution of the uncharged redox polymer, for example in diethyl ether, as described in Example 5, are used. Possible structures concerning the redox-active unit (RA) are shown in Table 1. The table shows monomeric classes and each a typical molecular representative. The integration of molecular RA into a polymer is not documented in the table but is well known to the skilled chemist from the literature. In Examples 1-5, the synthesis of the oligomers and polymers is presented in detail.

Possible combinations of redox systems (Hierarchy III)

All of the monomers shown above are redox systems, the more stable oxidation state being indicated. Depending on the substituents, they are water- and / or organic-soluble and are characterized by a localized electrochromic group, which is accompanied by a limited extent of HOMO and LUMO. As a result of the polymerization, the extent of the electrochromophore is generally not changed and, in particular, the polymerization does not necessarily produce electronic polymerization Conductivity such as in the case of polythiophene or polyaniline. Electron transfer within a polymer chain therefore occurs via an "electron hopping mechanism", as long as it is not in molecular contact with the nanoscopic conductor. An important aspect of this invention is that the slow "electron hoping mechanisme" between the redox systems in the polymer can be achieved by a fast electron flow in the nanoscopic ladder (after polymer self-assembly on graphene oxide and its reduction to graphene). The redox units in Table 1 are roughly divided into anodic and cathodic. Since most composite materials are to be used in organic as well as in aqueous systems, a precise specification of the standard reduction potentials is not possible. However, the potential difference between the compound with the most positive (1,4-di-t-butyl-2,5-dimethoxybenzene) and the most negative potential (dihydrotetrathia-anthracene) is> 2.3 V. Compared to a lithium electrode, of course, all redox systems are cathodic (range approx. +3.5 to +1.5 V).

The self-assembling surface modification can be done on graphene oxide, on oxidized CNTs or VGCNFs. As already mentioned, the negatively charged graphene oxide is particularly suitable as a precursor of a nanoscale current collector because the self-assembly of the polycationic redox polymers on suspended graphene oxide layers is particularly efficient. For self-assembly, a solution of graphene oxide (1-4 mg / ml, also in water) is slowly added to a solution of about 0.1-5 mg / ml of the polymer, preferably in water and under the action of ultrasound. The final mass ratio polymer / graphene oxide can be chosen from 2 to 10 (stable colloidal solution). In order to favor high current densities the ratio polymer / graphene oxide should be small. To reach high capacities it should be as high as possible. Each battery application can thus be optimized individually. The formation of the complex can be monitored by changing the zeta potential of the colloid. The strongly positive values indicate a double-sided coverage and sometimes multiple wrapping of the graphene oxide particles (see ). At a polymer / graphene oxide ratio> 10: 1, the efficient electron percolation threshold is exceeded.

Another feature of the present invention is the extremely large thickness scalability of the Generation III composite without significant loss of observed capacitance even at high current densities. The previously known redox polymer electrodes exhibited corresponding growth of the observed capacitance at high current densities up to a maximum of about 100 nm layer thickness. No other known additive (carbon black, electrically conductive polymers, etc.) has so far exhibited a similar performance enhancement in the electrochemical behavior of oligo or polymeric organic battery materials. In addition, it is shown with Examples 1-4 that the present invention has generality and applies to a wide variety of redox oligo- and polymers.

Flexible anodes, cathodes and complete batteries:

In its thickness of 0.1 to 1000 μm, the hierarchy III composite can be scaled over a considerable current density range without loss of capacity. Being largely made of a non-crystalline polymer, it is also flexible. As shown in Example 1, the composite can be applied to a bendable, 0.2 mm thick SIGRACET TF6 (SGL Carbon). The resulting battery electrode of hierarchy type III / I is therefore also bendable. At capacitances of 0.6 to 1.2 mAh / cm ² under load up to 16 mA / cm ² hardly measurable capacity loss is found (Example 1, electrode b)). In addition, the III / I electrode shows no capacity losses after 200 bending cycles (radius 1.8 cm). Since both anodic and cathodic redox polymers have the described thickness-scalable properties described in this patent, it is obvious that the expert is able to assemble a complete, flexible battery therefrom. It is therefore an important aspect of this invention that the use of Hierarchy III's composite on hierarchical I flexible current collector can result in thin flexible batteries. Thus, this invention represents a solution to the general problem concerning the production of flexible batteries for a variety of mobile applications.

Polymer redox batteries with extremely high surface-specific capacities and high current densities. For polymer redox batteries, large capacitors could not be produced at high current density. Because of the great thickness scalability of the hierarchy III composite, it is now possible, starting from the Hierarchy III composite, to connect the next higher hierarchy II of current and ion flux collectors to the hierarchy III without loss (Example 1, electrode c with hierarchy I / II / III) 21 mAh / cm ² ). For the first time, batteries based on organic (or organometallic) oligo- or polymers achieve performance values that have so far only been achieved by the commercial but heavy-metal-contaminated LIBs. The practical realization of Hierarchy II - Hierarchy III connection is in shown. Since the composite material (Hierarchy III) is scalable in the range 100 nm to 2 mm, the current collector of the next larger hierarchy II must have a Extension (in one dimension) from 100 nm to 2 mm. Suitable are, for example. the 1d graphite fibers of a carbon felt, the fibers of a carbon flow consisting of fibers in the thickness range about 5-30 μm, or thick (diameter> 500 nm) VGCFs (see - ). If the individual fibers are densely covered (or even better with a spacing also in the 5-30 μm (or about 1 μm for VGCF) area, then an optimal solvent and electron percolating system of 2 hierarchical generations (including the final one) is obtained flat collector plate calculated with 3 hierarchies). Example 1 shows that this easily achieves a surface-specific capacity of 21 mAh / cm ² (with a non-optimized layer thickness of about 2 mm) Current collector material of the hierarchy generation II (see .5).

It is an important part aspect of this invention that by using the thick-scalable composite hierarchy generation III and using a 3d current collector of the hierarchy generation II with matched current conductor dimensions in the micron range redox polymer batteries with similar good properties can be produced as the Have traditionally known batteries and accumulators. However, the redox polymer batteries are generally more environmentally friendly ("compostable" materials, not heavy metals, and with the option of using an aqueous electrolyte).

pictures:

Figure 1: Electrode material with hierarchy generations I and III:

1. a) Electron Conductor: Ia: Generation I Electron Conductor: macroscopic current collector (typically graphite plate) in electrical contact with: IIIa: Generation III electron conductor: nanoscopic current collector (typically reduced graphene oxide) in molecular self-assembled contact with redox polymer c).
2. b) ionic conductor: Ib: Generation I ionic conductor: Microscopic or macroscopic ions Bulk (typically aqueous or organic electrolyte, possibly polymeric or gelatinous) in ionic contact with: IIIb: Generation III ionic conductor: nanoscopic self-assembly tube system (typically redox polymer + graphene oxide / reduced graphene oxide).
3. c) redox oligo- or polymer or dendrimer.

Figure 2: Electrode material with hierarchy generations I, II and III

1. a) Electron conductor: Ia: Generation I electron conductor in electrical contact with: IIa: Generation II electron conductor: microscopic current collector (typically graphite fibers) in electrical contact with: IIIa: Generation III electron conductor in contact with redox polymer c).
2. b) ion conductor: Ib: Generation I ionic conductor in ionic contact with: IIb: Generation II ionic conductor: microscopic electrolyte channel (typically macropores in graphite felt or flow in ionic contact with IIIb: generation III ionic conductor in contact with c)
3. c) redox oligo- or polymer or dendrimer.

Abbreviations as in Fig. 1

Figure 3: Colloidal ladder / polymer carrier suspension, precursor of Generation III battery material

Colloid particles in aqueous solution consisting of nanoscopic electron conductor with negative surface charge (black) enveloped by the 2d and 1d nanoscopic polymeric redox carrier (vertically hatched). Total surface charge of colloid: positive. Solvent removal results in battery material (charge carriers / electrical conductors / ionic conductors of the hierarchical generation III ( and ).

K1: neg. Charged 2dim graphene oxide (2, with 2 nm <d2 <50) enveloped by pos. charged redox polymer / oligomer / dendrimer (1)

K2: pos. charged 1dim CNT (with 2 nm <d2 <50) or VGCNF (3, with d2 <500 nm) enclosed by the pos. charged redox polymer / oligomer / dendrimer (1) Positive total charge adjusted by ratio of 1: 2 or 1: 3 in the range 2: 8 (g / g)

d1: Thickness of 1 on conductor (0.5 <d1 <5 nm).

Figure 4: Hierarchy III and combinations Hierarchy III / II

4-1 and 4-2: Generation III electrode material

(Nanoscale with bulk dimensions) consisting of a mixture of the nanoscale composite material with additionally formed mesopores, formed by partial solvent removal from K1 (2-dimensional nanotubes) or from K2 (1-dimensional graphene oxide / graphene) (see ).

1a: oligomeric or polymeric reversible redox compound as polymer matrix in contact with 2a and 4a

2a: Electron percolating conductor system consisting of 1-dimer nanoscale conductor (for example CNT, multiwall CNT) with 0 nm <d4 <50 nm

3a: Electron percolating conductor system consisting of 2-diminus nanoscale conductors (for example graphene oxide / graphene) with 30 nm <d4 <50 nm

4: Ion percolating mesoporous ladder system, formed by self-assembly of the polymer and by interaction of the colloid during solvent removal

d3: depth of the nanoscale composite material, (100 nm <d3 <500 μm)

4-3: Abbreviation for 4-1 and 4-2 (composite material in a thickness of 100nm <d3 <500μm) used in 4-4 and 4-5.

4-4 and 4-5: macroporous, electron and electrolyte ions percolating support material with composite 4-3.

4-4: 2nd hierarchical generation electron and ion percolation system using 1-d graphitic fibers in the form of graphite felt, graphite flow or thick VGCF) with a 1d-conductor diameter of 500 nm <d5 <20 μm, an original porosity of 50 - 95%, and a thickness d4 of 100μm <d4 <10 mm. 4-5: Electron and electrolyte percolating carrier material consisting of carbon foam with a pore density of 10 - 200 ppi.

5: 1d current collector consisting of a large number of graphitized carbon fibers with a 1d conductor diameter of 500 nm <d5 <20 μm and 1 d length (L, 10 μm <L <10 cm). The fibers per se form an electron-percolating conductor system

(Points of contact)

6: Percolating, macroporous electrolyte conduit system with pore diameter 50 nm <d6 <100 μm. The pore system exists naturally and is reduced by the occupancy of the inner surface, but not prevented.

7. Carbon foam pore with pore diameter d8 (200 μm> d7> 10 μm)

8. Carbon foam pore wall with thickness 10nm <d5 <1 μm

Figure 5: Principally permissible polymer types with cationic total charge for self-assembly on graphene oxide

Figure Principles for the formation of polycationic redox polymer electron storage.

IIX : Polymers, Oligomers and Dendrimers with Redox Center (RA) in the Side Chain in the

polycationic state (prepared for self-assembly on graphene oxide).

IX : Polymers, Oligomers and Dendrimers with Redox Center (RA) in the Main Chain in the

polycationic state (prepared for self-assembly on graphene oxide).

X: Polymers, oligomers and dendrimers with redox center (RA) in the side or main chain in the neutral state, convertible by partial oxidation in the state IIX or IX.

R: non-redox active chain subunit

RA : electroactive side-chain subunit

RA * : electroactive backbone subunit

PC + : persistently positively charged subunit

n: number of subunits in the polymer, oligomer or dendrimer m +: number of persistent charges generated by (partial) oxidation of RA or RA * .

where m ⁺ <= n

example 1

Synthesis of Redox Polymer Poly (vinyl-diphenyl-4,4'-bipyridinium) dichloride: 4.5 g (0.8 mmol) bis- [1,1 '- (2,4-dinitrophenyl-4,4'-bipyridinium dichloride)]) ²⁷ : (1) and 1.7 g (8 mmol) of 4,4'-ethylenedianiline were dissolved in a mixture of methanol / water (8: 2 (v: v)) and poly (poly (methane) under reflux / Ar atmosphere for 14 days by Zincke reaction -condensed. The solvent was removed and the residue was refluxed in acetone for 6 h, filtered and the filter cake was washed with acetone and dried under high vacuum, yield: 3.19 g, 7.84 mmol), 98% poly (vinyl-diphenyl-4,4 '-bipyridinium), 12 << n <7. (1).

Preparation of colloidal solution: Variant 1: 3 g (7.36 mmol) 1 was dissolved in 750 ml H ₂ O / methanol (9: 1 (v: v)). 250 ml of an aqueous solution of graphene oxide (4 mg / ml, Graphenea SA, San Sebastián, Spain, with C: 49-56%, O: 41-50%, H, N, S, 0) was added to this solution under the action of ultrasound -2%) over 30 minutes. In a second variant, a polyvinylidene (PVDF) may additionally be added to the colloidal solution of variant 1 as a pore former, for. In an amount of 5% by weight based on the amount of redox polymer.

Preparation of the modified electrodes:

1. a) Hierarchy Type III / I on Rigid Current Collector:
   • a1) A glassy carbon electrode (Metrohm, Herisau, CH 0.07 cm ² ), or
   • a2) a 0.7 mm thick graphite electrode (SGL GROUP, SIGRACELL PV15 graphite plate, Wiesbaden DL) with the dimensions: and weight: 1 * 1 cm ² : 130 mg
2. b) Hierarchy type III / I on flexible current collector: a flexible graphite foil (SGL GROUP, SIGRACET bipolar plate TF6: 0.2 mm thick). Current collector weight: 1 * 1 cm ² : 24mg.
3. c) Hierarchy Type III / II / I on Rigid Current Collector: a carbon felt electrode (SGL GROUP, SIGRACELL GFD3 BATTERY FELT - R & D grade-surface treated) with macroscopic dimensions area and 3mm thickness was used Dimensions: Weight: 1 * 1cm ² : 21mg. The felt electrode was pressed against a SIGRACELL PV15 (graphite plate).

To the electrode a1), the colloidal solution was applied stepwise with a syringe, then heated in the oven at 50 ° C for 15 min and it was the next application of the colloidal solution. The sequence Colloidal solution Application / heating was repeated until the value indicated in the table was reached (applied measures).

Surface modification:

The electrodes a2) and b) were heated on a hot plate at 100 ° C. during the colloidal solution application. The amounts applied in the example resulted in layer thicknesses of 45 and 400 μm composite on the flat current collector (the corresponding specific electrode c) was treated stepwise with colloid solution similar to that described for a1), gently pressed and heated in the oven up to the weight ratio composite: carbon felt 10 mg / mg.

Conversion of graphene oxide into reduced graphene oxide and electrochemical properties of the resulting modified electrodes:

The electrodes a) -c) described above were switched as a working electrode in a 3-electrode system (reference electrode: Ag / AgCl / KCl, auxiliary electrode: Pt wire, electrolyte: 0.1 M KCl). The potential of the working electrode was repeatedly scanned over the range (0 → -1.3 → 0 V etc, for thick layers: potential range to -1.5 V) at 0.1 to 0.001 V / s, depending on the thickness of the composite layer, until the catalytic current in the range -0.6 to -1.3 had completely disappeared.

The capacity of the resulting modified electrodes prepared according to Variant 1 were measured in aqueous 0.1 M KCl electrolyte, Electrochemical measurements on polyimide (compound 1) Amperometry ^x Discret. Voltammetry * Electrode assembly Appl. spec. Dimensions / appl. spec. Capacity / obser. spec. Capacity / appl. Stoma density in (mg / cm ² ) / (mAh / cm ² ) / mAh / cm ² ) / (mA / cm ² ) Appl. spec. Dimensions / appl. spec. Capacity / obser. spec. Capacity / appl. Stoma density in (mg / cm ² ) / mAh / cm ² ) / (mAh / cm ² ) / (mA / cm ² ) Appl. spec. Dimensions / appl. spec. Capacity / obser. spec. Capacity / scan rate (mg / cm ² ) / (mAh / cm ² ) / (mAh / cm ² ) / (V / s) Electrolyte / solvent medium a1) ^v) 0.07 / 0.008 / 0.007 / 75 0.18 / 0.02 / 0.018 / 94 6.1 / 0.7 / 0.69 /0.005 0.1 M KCl / H ₂ O a1) ^w) - - 5.1 / 0.6 /0.21 /0.005 0.1 M KCl / H ₂ O a2) 51 / 5.8 / 5.7 / 8 51 / 5.8 / 5/16 115 / 13.7 / 13.3 / 0.0002 0.1 M KCl / H ₂ O b) before bending test ^y) 5.2 / 0.59 / 0.59 / 8 10.9 / 1.23 / 1.16 / 16 - 0.1 M KCl / H ₂ O b) after bending test ^y) 5.2 / 0.59 / 0.59 / 8 10.9 / 1.23 / 1.14 / 16 - 0.1 M KCl / H ₂ O Cyclic voltammetry * Amperometry ^x c) 195/22/21 / 0.001 88.5 / 10/10 / 0.001 - 0.1 M KCl / H ₂ O a1) polymer without graphene - - 2.1 / 0.28 / 0.07 / 0.001 0.1 M KCl / H ₂ O ^z) : Redox polymer Compound 1 accounts for 85% of the total weight (15% is Gaphen) ^*) : Values from CV Measurement: last entry Scan Rate in (V / s) ^x) ; Values from amperometry: last indication of imposed stoma density in (mA / cm ² ) ^y) : The composite-modified electrode strip (0.2 mm thick SIGRACET TF6) of 5.6 cm in length was compressed 200 times in 20 s in each case to form a semicircle with a radius of 2.8 cm and stretched again to full length. ^v) : polymer / graphene oxide ratio: 3/1 ^w) : polymer / graphene oxide ratio: 8/1

The redox polymer compound 1 accounts for 85% of the total weight (15% is Gaphen). Taking into account the graphene fraction results in a specific capacity of 137 mAh / g r. With hierarchy type III / I (a2, thickness of the battery material: 460 μm) 13.3 mAh / cm ^{2 are} measured. This results in a volumetric, area-specific charge density of 289 mAh / cm ³ , with> 97% coulometric efficiency being achieved.

Colloidal solutions, prepared according to variant 2, provide further increased stability and better reversibility.

Using the combination of hierarchy type III / II / I (c), at least 21 mAh / cm ^{2 can be achieved} at> 95% coulometric efficiency. Due to the additional use of the microscopic current collector (carbon felt), the specific capacity drops from 137 mAh / g to 115 mAh / g. On the other hand, however, higher area-specific capacities can be achieved. The capacity loss after 100 charge / discharge cycles in H ₂ O / KCl is <5%.

Example 2

Synthesis of the tri-viologen-tetra-bisanisidine redox oligomer (2):

Synthetic principle:

The precursor V2 ₁ * 2Cl ^- was prepared according to literature. Nanasawa, M et al; The Journal of Organic Chemistry 2000, 65 (2), 593-595 ,

To prepare V2 ₂ * 2 Cl ^- 2 g (3.56 mmol) of V2 ₁ * 2 Cl ^- in 250 ml of MeOH / H ₂ O (8: 2 (V: V)) was dissolved at 50 ° C, and with 2.2 g ( 9.05 mmol) of o-dianisidine in 200 ml in MeOH / H ₂ O (8: 2 (v: v)). The mixture was refluxed for 20 h, the solvents evaporated, and the residue washed with acetone. After drying, V2 ₂ * 2 Cl ^- (1.98 g, 82%) was obtained. For the preparation of the hexafluorophosphate salt of V2 ₃ , 0.5 g (0.73 mmol) V2 ₂ * 2 Cl ^- and 1.7 g (3.02 mmol) V2 ₁ * 2Cl ^- in 250 ml MeOH / H ₂ O (8: 2 (V: V)). ) refluxed for 72 h. The solvent was distilled off and the crude product was precipitated twice from methanol / ethyl acetate. The yellow product was taken up in 200 ml of methanol and added to 10 ml of a 3 M aq. NH ₄ PF ₆ solution. The filtrate was then precipitated from MeCN / diethyl ether. After drying under HV, V2 ₃ * 6 PF _{6 was obtained} as a dark yellow product (1.32 g, 86%). For the preparation of 2 * 6 PF ₆ , 0.9 g (0.42 mmol) of V2 ₃ * 6PF ₆ ^- and 0.55 g (2.25 mmol) of o-anisidine were refluxed in 100 nl MeCN for 48 h. The crude product was precipitated from the solution by addition of 250 ml of diethyl ether at room temperature, filtered, washed several times with MeOH and then with diethyl ether. The product was then redissolved several times in MeCN and precipitated with diethyl ether, and finally dried in HV: 2 × 6 PF ₆ ^- was obtained as a dark colored material (0.89 g, 93.4%).

¹ H NMR (CD ₃ CN, 250 MHz) δ: 9.19 (bs, Vio, 12H); 8.69 (bs, vio, 12h); 7.83 (s, CH _arom. , 4H); 7.74 (bs, CH _arom. , 10H); 7.56 (bs, CH _arom. , 4H); 7.27 (bs, CH _arom. , 4H); 6.87 (bs, CH _arom. , 2H); 4.45 (s, NH2, 4H); 4.11 (s, O-CH3, 12H); 4.05 (s, O-CH ₃ , 6H); 4.00 (s, O-CH ₃ , 6H).

Preparation of colloidal solution: 0.3 mg of multi-wall carbon nanotubes carbonated (MWCNT-COOH (8%)) with degree of carboxylation> 8%, average diameter of 9.5 nm and average length of 1.5 μm, Aldrich, No. 755125) suspended in 6 ml of DMF by short-term ultrasound treatment at 0 ° C. 1.5 mg of Oligomer 2 was dissolved in 20 ml of DMF, added slowly to the MWCNT-COOH dispersion and further sonicated for 30 minutes.

Preparation of Modified Electrodes: Electrodes of type a1) (hierarchical type III / I on rigid glassy carbon) were prepared as described in Ex. The structure of the modification layer was also as described for a1) systems in Example 1.

Electrochemical Properties of the Resulting Modified Electrode Only thin-layer modified electrodes were investigated. The thickness scalability was not investigated in detail. Electrochemical measurements on compound 2 Cyclic voltammetry * electrode type Appl. spec. Dimensions / appl. spec. Capacity / obser. spec. Capacity / scan rate Appl. spec. Dimensions / appl. spec. Capacity / obser. spec. Capacity / scan rate Electrolyte / solvent (mg / cm ² ) / (mAh / cm ² ) / (mAh / cm ² ) / (V / s) (mg / cm ² ) / (mAh / cm ² ) / (mAh / cm ² ) / (V / s) a1) 0.66 / 0.04 / 0.04 / 0.05 1.65 / 0.1 / 0.1 / 0.01 0.1 M LiClO ₄ / CH ₃ CN a1) 0.66 / 0.04 / 0.04 / 0.05 1.65 / 0.1 / 0.1 / 0.01 0.1 M KCl / H ₂ O

The redox oligomer 2 corresponds to 83% by weight of the composite (17% is MWCNT-COOH). Specific capacities> = 0.1mAh / cm ² . Coulomb efficiencies> 95% at 101 mAh / g are observed in both aqueous and organic electrolytes with hierarchy combinations III / I. The capacity loss is <5% over 30 CV charge / discharge cycles in MeCN / LiClO ₄ .

Comparative Example 1

Synthesis of the Partially Oxidized Poly (vinylferrocene (PVFc): PVFc (3) is commercially available (Polysciences Inc., Warrington, PA).) The n≈50 polymer partially transformed into PVFc ^{z +} in a 2-phase solvent system as described ■ zNO ₃ ^- (10 <z <30%) oxidized ²⁸

Preparation of the colloidal solution: An aqueous graphene dispersion (. 0:29 g in 580 ml, specifications, see Example 1) was added dropwise located to the ultrasonic bath PVFC ^{z +} ■ ZnO ₃ ^- (3) - suspension (1.27 l, 6 mmol = 01.27 g Containing PVFc). Subsequently, the solution was distilled with 0.68 l. Diluted with water and sonicated for another 30 minutes.

Preparation of Modified Electrodes: Electrodes of type a1) (hierarchical type III / I on rigid glassy carbon) were prepared as described in Ex. The structure of the modification layer was also as described for a1) systems in Example 1).

Conversion of graphene oxide into reduced graphene oxide and electrochemical properties of the resulting modified electrodes:

The reduction of graphene oxide in the composite material of the modified electrode was electrocatalytically in a solution of 0.1 M LiClO _4/4 × 10 ^-3 M methyl viologen.

The potential of the working electrode (details as in Ex. 1) was scanned until the catalytic stream had disappeared. After the electrochemical reduction, the modified electrode was at 50 ° C for 30 min in dist. Washed water.

The properties of the poly-3 composite electrode in aqueous and organic electrolytes, as well as in comparison to the electrode material without graphene are summarized in the table: Electrochemical measurements on poly (vinylferrocene) (compound 3) Amperometry ^x Discret. Voltammetry * electrode type appl. spec. Dimensions / appl. spec. Capacity / obser. spec. Capacity / appl. Stoma density in (mg / cm ² ) / (mAh / cm ² ) / mAh / cm ² ) / (mA / cm ² ) appl. spec. Dimensions / appl. spec. Capacity / obser. spec. Capacity / appl. Stoma density in (mg / cm ² ) / (mAh / cm ² ) / mAh / cm ² ) / (mA / cm ² ) appl. spec. Dimensions / appl. spec. Capacity / obser. spec. Capacity / scan rate (mg / cm ² ) / (mAh / cm ² ) / (mAh / cm ² ) / (V / s) Electrolyte / solvent medium a1 0.014 / 0.0015 / 0.0014 / 7 0.024 / 0.0025 / 0.0023 / 5.4 2 / 0.21 / 0.21 / 0.01 0.1 M LiClO ₄ / CH ₃ CN a1 - - 2 / 0.21 / 0.21 / 0.01 0.1 M LiClO ₄ / H ₂ O a1 Pure redox polymer without graphene - - 0.43 / 0.054 / 0.01 / 0.01 0.1 M LiClO ₄ / CH ₃ CN

The composite material consists of 88% of the redox polymer (12 percent by weight is deposited on the graphene). The composite allows specific capacities> 0.21 mAh / cm2 at 29 μm layer thickness and> 99% Coulomb efficiency (capacity density of the material (including graphene) = 114 mAh / g). The capacity loss after 300 charge / discharge cycles is <5%.

Example 4

Synthesis: 1,4,5,8-Naphthalenetetracarboxylic dianhydrides (NTCDA, 0.536 g, 2 mmol) and 2,3,5,6-tetramethyl-1,4-diaminobenzene (0.32 g, 2 mmol) were dissolved in dimethylacetamide (DMA) and polycondensed at 140 ° C for 3 days. The precipitated product was isolated by filtration, washed with ethanol and water, and dried under high vacuum at 50 ° C (0.25, 0.64 mmol (32%), n could not be determined.

Preparation of the colloidal solution: 0.3 g (0.75 mmol) of 4 was dissolved in 100 ml of DMF and admixed with ultrasound with 15 ml of a graphene oxide suspension (4 mg / ml). After addition, the suspension was sonicated for a further 30 min.

Electrode modification: 0.29 ml of the composite suspension was added dropwise to an FTO glass electrode (Fluorine doped tin oxide, 10 Ω / sq, 1 * 1 cm ² dimensions) (using the "drop-casting" described in Example 1). Method).

The activation was carried out either electrochemically (as described in Example 1) or thermally. The electrochemical activation was carried out by self-catalytic reduction without additional viologen, in principle as shown in Example 1, wherein 0.5 M TEABF ₄ in CH ₃ CN was used as the electrolyte, the scan range from 0 to -2.5 V and a scanning speed of 0.005 to 0.05 V. / s was created. In the alternative method, the reduction of graphene oxide was thermally effected by heating the FTO glass plate to 400 ° C for 2 hours.

Electrochemical properties with thermal and electrochemical reduction, as well as with the use of organic electrolyte / solvent are listed in the table: Cyclic voltammetric investigations on polyimide composite 4 on FTO electrodes Comparison of electrochemical and thermal transformation of graphene oxide in graphene All electrodes consist of FTO on glass The reduction was carried out electrochemically or thermally. appl. spec. Dimensions / appl. spec. Capacity / obser. spec. Capacity / scan rate (mg / cm ² ) / (mg / cm ² ) / (mAh / cm ² ) / (mAh / cm ² ) / (V / s) appl. spec. Dimensions / appl. spec. Capacity / obser. spec. Capacity / scan rate (mg / cm ² ) / (mAh / cm ² ) / (mAh / cm ² ) / (V / s) Electrolyte / solvent medium Electroreduction a1 (FTO) *, 0.36 / 0.044 / 0.044 / 0.01 0.89 / 0.11 / 0.089 / 0.01 0.5M TEABF ₄ / CH ₃ CN Therm. Reduction a1 (FTO) * 0.36 / 0.044 / 0.044 / 0.01 0.89 / 0.11 / 0.093 / 0.01 0.5M TE-ABF ₄ / CH ₃ CN a1 (FTO) pure polymer 0.22 / 0.03 / 0.001 / 0.01 0.5M TE-ABF ₄ / CH ₃ CN * T = 130 ° C, 20 min

The thermal and electrochemical methods lead to identical results. The thermal method can only be applied to a few polymers. The redox material 4 makes> 90% of the Total weight off. Specific capacities> 0.11 mAh / cm ² are possible, both reduction methods provide Coulombefficiencies> 80%, capacity losses after 30 CV charging / discharging cycles were <5%.

Example 5

Synthesis of poly-o-dianisidine-NTCDA (4a)

Synthesis: 488.00 mg (2.0 mmol) of o-dianisidine in 15 ml of dimethylacetamide (DMA) and 538.00 mg (2.0 mmol) of 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA) in 20 ml DMA each at 40 ° C for 20 minutes and dissolved with stirring. The solutions were combined and the polycondensation was carried out at 140 ° C for three days under reflux. The red-brown precipitate was separated after cooling to RT with a glass frit and washed with 20 ml of water and then dried at 40 ° C under high vacuum (yield: 580 mg, 61%). About 30 mg of this amount was dried for one day at 180 ° C and then passed to the spectroscopic analysis.

¹ H-NMR (DMSO, 250 MHz): 8.818-8.620 (s, 4H); 7.561 (m, 6H); 3.905 (s, 6H)

Preparation of colloidal solution:

30 mg of poly-o-dianisidine-NTCDA (4a) was dispersed in 15 ml of diethyl ether under the action of ultrasound for 30 minutes. The dispersion was added to 1 mg of graphene oxide in 5 ml of water. The two-phase system was stirred mechanically for 24 h. It formed an emulsion. After separation of the two liquid phases, the molecular complex poly-o-dianisidine-NTCDA @ GO was in the aqueous phase.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• WO 2014/093876 A1 [0010]

Cited non-patent literature

• Magasinski (Maginski, A. et al; Nature Materials, 2010, 9 (4), 353-358) [0019]
• Nanasawa, M et al; The Journal of Organic Chemistry 2000, 65 (2), 593-595 [0121]

Claims (19)

An electrode material in the form of a colloidal solution of a molecular complex comprising at least one maximum nanoscale redox-active organic oligomer and / or polymer and at least one nanoscale graphitic material, wherein these in a weight ratio of redox-active oligomer and / or polymer and graphitic material of 1: 1 to 20: 1 and wherein the redox-active organic oligomer and / or polymer forms a complex with the graphitic material. Electrode material after Claim 1 , wherein this electrode material does not contain heavy metals / heavy metal ions. Electrode material after Claim 1 or 2 wherein the oligomers and / or polymers are at least partially present as dendrimers. An electrode material according to any one of the preceding claims, wherein the graphitic material is at least one selected from graphene or graphene oxide, at least partially oxidized CNTs or VGCNFs, in particular graphene oxide, such as reduced graphene oxide. Electrode material according to one of the preceding claims, wherein the redox-active organic oligomer and / or polymer at least two electrophorus groups predominantly cathodic character from the classes of electrophorus groups of aliphatic or aromatic N-oxides, 9-alkyl and aryl-carbazoles, 1,4-di Alkyloxy and aryloxy-2,5-tert-butylbenzenes, benzoquinone diimines, N-alkyl-phenothiazines, or at least two predominantly anodic electrophorus groups selected from the classes of electrophore groups derived from bipyridinium salts, quinones, anthachinones or aromatic 1,4 or 1 , 2 dioxo compounds, aromatic tetracarboxylic diimides, aromatic dicarboxylic acid salts, benzylic or aromatic disulfides. Electrode material according to one of the preceding claims, wherein said oligomers and / or polymers comprise multiple, localized or conjugated, reversibly oxidizable / reducible electrophors, in particular having at least two electrophore groups selected from the following electrophoretic groups:

N, N'-dimethyl-4,4'-bipyridinium

N, N'-dimethyl-2,2'-bipyridinium

anthraquinone

Phenamthren-9,10-dione

N, N'Dimethyl-Pyromel-litdiimid

Li terephthalate

Dihydrotetrathiaanthracen

(2,2,6,6-tetramethylpiperidin-1-yl) oxyl

galvinoxyl

9-Methylcarbazole

1,4-di-t-butyl-2,5-dimethoxybenzene

N, N'-2,5-cyclohexa-diene-1,4-diylidenebis

n-methyl phenothiazines An electrode material according to any one of the preceding claims, which additionally contains a pore-forming polymer, such as polyvinylidene fluoride, in an amount of from 1 to 10% by weight, based on the redox polymer. A process for producing an electrode with an electron material according to any one of Claims 1 to 7 comprising applying the electrode material in the form of a colloidal solution to a current collector; Removing the solvent while maintaining the molecular complex structure of the electrode material of the graphitic material and the redox-active organic oligomer and / or polymer on the current collector. Method according to Claim 7 further comprising the step of chemical reduction, in particular electrochemical reduction, such as by electrocatalytic reduction, of the graphene oxide present in the electrode material. Electrode with an electrode material according to one of Claims 1 to 7 and a current collector that is at least microscale. Electrode after Claim 10 wherein the current collector is one with carbon fibers such as felt or nonwoven fabric; in the form of a fabric or foam, such as in the form of a 3D carbon foam carrier material, in the form of VGCF; in the form of a foil or plate. Electrode after Claim 10 or 11 in which the electrode is a flexible electrode, in particular one with a carbon foil as the current collector and an electrode material with reduced graphene oxide or graphene as the graphitic material. An electrochemical cell having a cathode and an anode, wherein an electrode material according to one of Claims 1 to 7 and / or an electrode according to one of Claims 10 to 12 at least one of the cathode or anode forms. Electrochemical cell after Claim 13 wherein the cathode and the anode are an electrode material according to any one of Claims 1 to 7 having. Electrochemical cell after one of Claims 13 or 14 , wherein this cell is flexible. Electrochemical cell after one of Claims 13 to 15 In particular, one of these organic electrolytes has a cell voltage of ≥ 1.5 V such as ≥ 2 V. Electrochemical cell after one of Claims 13 to 16 , which has a surface specific capacity of ≥ 20 mAh / cm ² with a total thickness of the electrochemical cell of ≤ 1 cm. A process for preparing a viologen-group-containing oligomer or polymer comprising the steps of: - providing a 1,1- (2,4-dinitrophenyl) -4,4-bipyridinium dichloride and a second moiety comprising at least two amino groups; - Reacting these two compounds to release a 2,4-dinitroaniline to give an oligomeric or polymeric viologen-containing compound. Method according to Claim 18 , wherein the reaction takes place after a Zincke reaction.

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