EP2661781A1

EP2661781A1 - Electrode materials and method for producing same

Info

Publication number: EP2661781A1
Application number: EP12704053.3A
Authority: EP
Inventors: Robert Bayer; Bastian Ewald; Jordan Keith Lampert; Simon SCHRÖDLE
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2011-02-14
Filing date: 2012-02-10
Publication date: 2013-11-13
Also published as: CN103354959A; JP2014507050A; WO2012110404A1; KR20140001997A

Abstract

The invention relates to a method for producing electrode materials, characterized in that the components (A) at least one iron compound in which Fe is present in the oxidation state of +2 or +3, (B) at least one phosphorous compound, (C) at least one lithium compound, (D) at least one carbon source that can be a separate carbon source or the same at least one iron compound (A) or phosphorous compound (B) or lithium compound (C), (E) optionally at least one reducing agent, (F) optionally at least one other metal compound that has a metal that is different from iron, and (G) optionally water or at least one organic solvent are (a) mixed together, (b) spray dried together using at least one device that uses at least one spray nozzle for spraying, and (c) thermally treated at temperatures ranging from 350 to 1200 °C.

Description

Electrode materials and process for their preparation

The present invention relates to a process for the production of electrode materials, which is characterized in that

(a) mixed together:

(A) at least one iron compound in which Fe is in the oxidation state +2 or +3,

(B) at least one phosphorus compound,

(C) at least one lithium compound,

(D) at least one carbon source, which may be a separate carbon source or at least one iron compound (A) or phosphorus compound (B) or lithium compound (C),

(E) optionally at least one reducing agent,

(F) optionally at least one further metal compound which has a metal other than iron,

(G) optionally water or at least one organic solvent,

(b) spray-dried with each other by means of an at least apparatus which uses at least one spray nozzle for spraying

(c) thermally treated at temperatures in the range of 350 to 1200 ° C.

Furthermore, the present invention relates to electrode materials which are obtainable by the process according to the invention. Furthermore, the present invention relates to the use of electrode materials according to the invention in electrochemical cells. In the search for advantageous electrode materials for batteries which use lithium ions as conductive species, numerous materials have hitherto been proposed, for example lithium-containing spinels, layered mixed oxides such as lithiated nickel-manganese-cobalt oxides and lithium-iron-phosphates. Lithium iron phosphates are of particular interest because they contain no toxic heavy metals and in many cases are very robust against oxidation and water. A disadvantage of lithium iron phosphates may be the comparatively low energy density.

One problem is that it is often desired that lithium iron phosphates should be very finely divided to have suitable electrochemical properties. With finely divided lithium iron phosphates, high levels of dust and poor rheological properties are often observed, which cause problems in production and processing.

It is therefore the object to provide a method for producing electrode materials, which is simple, requires as few steps as possible and provides access to chemically insensitive electrode materials with good rheological properties. A further object was to provide chemically insensitive electrode materials which can be produced with as little effort as possible and which do not cause any great dust load. chen. Furthermore, the object was to provide electrochemical cells which have overall positive application properties. Examples of application properties are the properties when processing into batteries or battery components as well as the properties of the batteries produced therefrom.

Accordingly, the method defined above was found, hereinafter also referred to as inventive method.

For carrying out the process according to the invention, in stage (a) several of the starting materials, preferably all the starting materials involved, are mixed in several or preferably in one step. As vessels for mixing, for example, stirred tank and stirred flasks are suitable.

In the following, the starting materials are further characterized.

The starting material (A) is selected from at least one iron compound, hereinafter also called iron compound (A). In this case, iron compound (A) is chosen from those in which iron, ie Fe, is present in the oxidation state +2 or +3. These are preferably inorganic iron compounds, for example iron oxide such as FeO, Fe20 ₃ or Fe ₃ 0 ₄ , iron hydroxide, for example Fe (OH) ₃ , FeOOH, furthermore FeC0 ₃ , hydrous iron oxide, also written as FeO aq or Fe ₂ <D ₃ -aq, or water-soluble iron salts such as FeS0 ₄ , Fe2 (S0 ₄ ) ₃ , iron (II) acetate, iron phosphate, iron phosphonate, iron citrate, lithium iron citrate, ammonium iron citrate, iron lactate, furthermore basic iron carbonate and iron citrate. In the context of the present invention, carboxylic acid salts of iron are to be considered as inorganic iron compounds.

Preferred iron compounds (A) are Fe (OH) _3, basic Fe (lll) hydroxide, particularly FeOOH, ammonium citrate, Fe20 _3, Fe ₃ 0 _4, iron acetate, iron citrate, iron lactate, iron phosphate, iron carbonate and Eisenphosphonat.

In one embodiment of the present invention, at least two iron compounds are selected as starting material (A), at least one of which has at least one, preferably at least two, Fe in the oxidation state +2 or +3. In one embodiment of the present invention, as starting material (A) at least three iron compounds are chosen, all of which have Fe in the oxidation state +2 or +3.

In another embodiment of the present invention, the starting material (A) selected is exactly one iron compound present in Fe in the oxidation state +2 or +3. Starting material (A) can be used, for example, as an aqueous solution, as an aqueous suspension or as a powder, for example with average particle diameters in the range from 10 to 750 nm, preferably in the range from 25 to 500 nm. As starting material (B), at least one phosphorus compound is chosen , hereinafter also called phosphorus compound (B), selected from phosphine and compounds in which phosphorus is in the oxidation state +1 or +3 or +5, for example phosphines having at least one alkyl group or at least one alkoxy group per molecule, phosphorus halides, phosphonic acid , hypophosphorous acid and phosphoric acid. Preferred phosphanes are PH 3 and phosphanes of the general formula (I)

P (R ¹ ) _r (X ¹ ) sH _t (I) where the variables are chosen as follows:

R ¹ may be different or the same and is selected from phenyl and preferably C 1 -C 10 -alkyl, cyclic or linear, for example methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, cyclopentyl, iso-amyl, iso-pentyl, n-hexyl, iso-hexyl, cyclohexyl, and 1, 3-dimethylbutyl, preferably n-Ci-Cö-alkyl, more preferably methyl, Ethyl, n-propyl, isopropyl, and most preferably methyl or ethyl.

If a substance has a plurality of alkoxy groups per mole, as R ¹ may be different or preferably identical and are selected from the above-mentioned Ci-C _ß alkyl radicals.

X ¹ may be different or the same and is selected from halogen, phenoxy groups and alkoxy groups, preferably of the formula OR ¹ , in particular methoxy and ethoxy, and wherein

Halogen is preferably bromine and particularly preferably chlorine, r, s are selected from integers in the range from zero to three,

t is selected from integers ranging from zero to two, where the sum is r + s + t = 3, and where at least one of the inequalities r 0

s 0 is satisfied. In one embodiment of the present invention, phosphorus compound (B) is selected from compounds of general formula P (OR ¹ ) ₃ , wherein R ^{1 is} different or preferably may be the same and selected from phenyl and C 1 -C 10 -alkyl, particularly preferred are P (OCH 3) 3 and P (OC ₂ H ₅ ) ₃ .

As phosphonic acid, hypophosphorous acid and phosphoric acid can be selected in each case the free acid or corresponding salts, in particular lithium and ammonium salts. As phosphoric acid and phosphonic acid can be selected in each case the mononuclear acids H ₃ P0 ₃ or H ₃ P0 ₄ , but also two-, three- or more-nuclear acids, for example I-ÜP2O7 or polyphosphoric acid. In one embodiment of the present invention, as the starting material (B), two or more phosphorus compounds (B) are selected. In another embodiment of the present invention, exactly one phosphorus compound (B) is chosen.

The starting material (C) used is at least one lithium compound, also called lithium compound (C), preferably at least one inorganic lithium compound. Examples of suitable inorganic lithium compounds are lithium halides, for example lithium chloride, furthermore lithium sulfate, lithium acetate, LiOH, Li 2 CO ₃ , L 12 O and LiNO ₃ ; preferred are L12SC, LiOH, Li2C0 ₃ , L12O and LiN0 ₃ . In this case, lithium compound can contain water of crystallization, for example LiOH ^■ H2O.

In a specific embodiment of the present invention, phosphorus compound (B) and lithium compound (C) are each selected from lithium phosphate, lithium orthophosphate, lithium metaphosphate, lithium phosphonate, lithium phosphite, lithium hydrogen phosphate or lithium dihydrogen phosphate, ie lithium phosphate, lithium phosphonate, lithium phosphite or lithium (di) Hydrogen phosphate can each serve simultaneously as a phosphorus compound (B) and as a lithium compound (C).

As starting material (D), at least one carbon source, also called carbon source (D) for short, may be used, which may be a separate carbon source or at least one iron compound (A) or phosphorus compound (B) or lithium compound (C).

For the purposes of the present invention, a separate carbon source (D) is to be understood as meaning that a further starting material is used which is selected from elemental carbon in a modification which conducts the electric current or a compound which is used in the thermal treatment in step (c) is decomposed into carbon and different from iron compound (A), phosphorus compound (B) and lithium compound (C).

As carbon source (D), for example, carbon in a modification that conducts the electric current is suitable, for example, carbon black, graphite, graphene, carbon nanotubes or activated carbon. Examples of graphite are not only mineral and synthetic graphite, but also expanded graphite and intercalated graphite.

Carbon black may, for example, be selected from lampblack, furnace black, flame black, thermal black, acetylene black, carbon black and furnace carbon black. Carbon black may contain impurities, for example hydrocarbons, in particular aromatic hydrocarbons, or oxygen-containing compounds or oxygen-containing groups, for example OH groups. Furthermore, sulfur or iron-containing impurities in carbon black are possible. Further suitable carbon sources (D) are compounds of carbon which are decomposed to carbon during the thermal treatment in step (c). For example, synthetic and natural polymers, unmodified or modified, are suitable. Examples of synthetic polymers are polyolefins, for example polyethylene and polypropylene, furthermore polyacrylonitrile, polybutadiene, polystyrene, and copolymers of at least two comonomers selected from ethylene, propylene, styrene, (meth) acrylonitrile and 1,3-butadiene. Furthermore, polyisoprene and polyacrylates are suitable. Particularly preferred is polyacrylonitrile.

In the context of the present invention, polyacrylonitrile is understood to mean not only polyacrylonitrile homopolymers, but also copolymers of acrylonitrile with 1,3-butadiene or styrene. Preference is given to polyacrylonitrile homopolymers.

In the context of the present invention, polyethylene is understood to mean not only homo-polyethylene, but also copolymers of ethylene which contain at least 50 mol% of ethylene in copolymerized form and up to 50 mol% of at least one further comonomer, for example Olefins such as propylene, butylene (1-butene), 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-pentene, also isobutene, vinyl aromatics such as styrene, further

(Meth) acrylic acid, vinyl acetate, vinyl propionate, C 1 -C 10 -alkyl esters of (meth) acrylic acid, in particular methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, furthermore maleic acid, maleic acid acid anhydride and itaconic anhydride. Polyethylene may be HDPE or LDPE.

In the context of the present invention, polypropylene is understood to mean not only homo-polypropylene but also copolymers of propylene which contain at least 50 mol% of propylene polymerized and up to 50 mol% of at least one further comonomer, for example ethylene and α-propylene. Olefins such as butylene, 1-hexene, 1-octene, 1-decene, 1-dodecene and 1-pentene. Polypropylene is preferably isotactic or substantially isotactic polypropylene. In the context of the present invention, polystyrene is understood to mean not only homopolymers of styrene, but also copolymers with acrylonitrile, 1,3-butadiene, (meth) acrylic acid, C 1 -C 10 -alkyl esters of (meth) acrylic acid, divinylbenzene, in particular 1, 3-divinylbenzene, 1, 2-diphenylethylene and α-methylstyrene.

Another suitable synthetic polymer is polyvinyl alcohol.

Suitable natural polymers as carbon source (D) are for example starch, cellulose, alginates (eg agar agar, furthermore pectins, gum arabic, oligo and polysaccharides, guar gum and locust bean gum as well as amylose and amylopectin.) Also suitable Examples of modified natural polymers include methanol-etherified starch, acetylated starch and acetylcellulose, and further phosphated and sulfated starch.

Furthermore, carbides are suitable as the carbon source (D), preferably covalent carbides, for example iron carbide Fe ₃ C.

Furthermore, low volatility low molecular weight organic compounds are suitable as carbon source (D). Particularly suitable compounds are those which react at temperatures in the

Range of 350 to 1200 ° C does not evaporate, but decompose, for example as a solid or in the melt. Examples are dicarboxylic acids, for example phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, tartaric acid, citric acid, pyruvic acid, furthermore sugars, for example monosaccharides having 3 to 7 carbon atoms per molecule (trioses, tetroses, pentoses, hexoses, heptoses) and condensates of monosaccharides such as for example, di-, tri- and oligosaccharides, in particular lactose, glucose and fructose, as well as sugar alcohols and sugar acids, for example aldonic acids, ketoaldonic acids, uronic acids and aldaric acids, in particular galactonic acid. Further examples of low molecular weight organic compounds as carbon source (D) are urea and its less volatile condensates biuret, melamine, melam (N2- (4,6-diamino-1, 3,5-triazin-2-yl) -1, 3, 5-triazine-2,4,6-triamine) and Meiern (1, 3,4,6,7,9,9b-heptaazaphenalene-2,5,8-triamine). Further examples of carbon sources (D) are salts, preferably iron, ammonium salts and alkali metal salts, more preferably iron, sodium, potassium, ammonium or lithium salts, of organic acids, for example acetates, propionates, lactates, citrates, tartrates, benzoates , Butyrates. Particularly preferred examples are ammonium acetate, potassium ammonium tartrate, potassium hydrogen tartrate, potassium sodium tartrate, sodium tartrate (disodium tetradrate), sodium hydrogentartrate, lithium hydrogentate, lithium ammonium tartrate, lithium tartrate, lithium citrate,

Potassium citrate, sodium citrate, iron acetate, lithium acetate, sodium acetate, potassium acetate, lithium lactate, ammonium lactate, sodium lactate and potassium lactate. In a specific other embodiment of the present invention are selected as the carbon source (D) and phosphorus compound (B) an organic phosphorus compound, which may include, for example, trimethyl trimethylate, triethyl phosphite, triphenyl phosphine and triphenylphosphine oxide (CeHs ^ PO.

In a specific embodiment of the present invention, as the carbon source (D) and the lithium compound (C), lithium acetate, lithium lactate or lithium hydrogen tartrate are respectively selected. Lithium compound (C) Lithium acetate, lithium lactate or lithium hydrogen tartrate can each serve simultaneously as carbon source (D).

In a specific embodiment of the present invention, the carbon source (D) and iron compound (A) are each selected from iron acetate, iron citrate, iron carbide or ammonium citrate, i. the iron compound (A) iron acetate, iron citrate, iron carbide or ammonium citrate can simultaneously serve as carbon source (D).

In a specific embodiment of the present invention, the iron compound (A), carbon source (D) and lithium compound (C) are each selected from lithium iron citrate, i. Lithium-iron citrate can in each case simultaneously serve as iron compound (A), carbon source (D) and as lithium compound (C).

In a specific embodiment of the present invention, two different carbon sources (D) and two different phosphorus compounds (B) are chosen. As starting material (E), it is also possible to use a reducing agent, also called reducing agent (E) for short. As the reducing agent (E), it is possible to use gaseous, liquid or solid substances which, under the conditions of step (a), (b) or (c), convert iron, if necessary, into the oxidation state +2. In one embodiment of the present invention, a solid reducing agent (E) is selected from a metal, for example nickel or manganese, or a metal hydride.

As gaseous reducing agent (E) can be used for example hydrogen, carbon monoxide, ammonia and / or methane.

A very suitable reducing agent is H3PO3 and its ammonium and lithium salts.

Other suitable reducing agents are metallic iron and iron pentacarbonyl. In a preferred embodiment of the present invention, phosphoric acid (B) and reducing agent (E) are each selected to be H3PO3, ie H3PO3 can simultaneously serve as phosphorus compound (B) and as reducing agent (E). In one embodiment of the present invention, no reducing agent (E) is used.

As starting material (F) it is possible to use at least one further metal compound in which the one or more metals are different from iron, in short also called metal compound (F). In this case, it is preferable to use one or more metals from the first period of the transition metals as the metal. It is particularly preferable to choose metal compound (F) from compounds of Ti, V, Cr, Mn, Co, Ni, Mg, Al, Nb, W, Mo, Cu and Zn. Sc, V, Mn, Ni, Co. Most preferably one selects metal compound (F) from oxides, hydroxides, carbonates and sulfates of metals of the first period of the transition metals.

Metal compound (F) may be anhydrous or hydrous. Metal cation in metal compound (F) can be present in complexed form, for example as hydrate complex, or uncomplexed.

Metal compound (F) can be a salt, for example halide, in particular chloride, furthermore nitrate, carbonate, sulfate, oxide, hydroxide, acetate, citrate, tartrate or salts with different anions. Preferably, salts are selected from oxides, carbonates, hydroxides and nitrates, basic or neutral. Very particularly preferred examples of metal compounds (F) are oxides, hydroxides, carbonates and sulfates.

In another embodiment of the present invention, metal compound (F) is selected from fluorides, for example as alkali metal fluoride, especially sodium fluoride. In one embodiment of the present invention, metal compound (F) may function as one or the sole carbon source (D), exemplified by nickel acetate, cobalt acetate, zinc acetate and manganese (II) acetate.

In one embodiment of the present invention, metal compound (F) may act as one or the sole reducing agent (E). Examples include manganese (II) acetate, MnC0 ₃ , MnS0 ₄ , nickel lactate, manganese hydride, nickel hydride, nickel suboxide, nickel carbide, manganese carbide and manganese (ll) lactate called.

In one embodiment of the present invention, one or more solvents may be added in step (a), for example one or more organic solvents (G) and / or water. Organic solvents (G) are to be understood as meaning those substances which are liquid at the temperature of step (a) of the process according to the invention and which have at least one CH bond per molecule. In one variant, water and an organic solvent (G) are added. Examples of suitable organic solvents (G) are, in particular, halogen-free organic solvents. such as methanol, ethanol, isopropanol or n-hexane, cyclohexane, acetone, ethyl acetate, diethyl ether and diisopropyl ether.

Preference is given to water.

Without wishing to prioritize any particular theory, it is possible that certain organic solvents (G), such as secondary or primary alkanols, may also act as reducing agents (E). The mixing in step (a) can be carried out, for example, by stirring one or more suspensions of the starting materials (A) to (D) and optionally (E), (F) and (G). In other embodiments, the starting materials (A) to (D) and optionally (E) and (F) are intimately mixed together as solids. In another embodiment of the present invention, the starting materials (A) to (D) and optionally (E), (F) and (G) may be kneaded together to form a paste.

In one embodiment of the present invention, the mixing in step (a) is carried out at temperatures in the range from zero to 200 ° C, preferably it is carried out at temperatures in the range of room temperature up to 1 10 ° C, particularly preferably up to 80 ° C.

In one embodiment of the present invention, the mixing in step (a) is carried out under atmospheric pressure. In other embodiments, the mixing is carried out at elevated pressure, for example at 1, 1 up to 20 bar. In other embodiments, the mixing in step (a) is carried out under reduced pressure, for example at 10 mbar up to 990 mbar.

The mixing in step (a) can be carried out over a period in the range of one minute to 12 hours, preferred are 30 minutes to 4 hours, more preferably 45 minutes to 2 hours.

In one embodiment of the present invention, the mixing in step (a) is performed in one step.

In another embodiment, the mixing in step (a) is carried out in two or more stages. Thus, it is possible, for example, first to dissolve or suspend iron compound (A) and lithium compound (C) together in water, then to mix with phosphorus compound (B) and carbon source (D) and then optionally with reducing agent (E) and / or further metal compound (F) to mix. In one embodiment, initially introducing water and / or organic solvent, then added successively with lithium compound (C), iron compound (A), phosphorus or Phosphorus compound (D), carbon compound (B) and optionally with reducing agent (E) and / or further metal compound (F).

Step (a) gives a mixture of at least one iron compound (A), at least one phosphorus compound (B), at least one lithium compound (C), at least one carbon source (D), optionally reducing agent (E), optionally further metal compound ( F) and preferably water and / or at least one organic solvent (G) in pasty form, as a water-containing powder, as a suspension or as a solution. In step (b) of the process according to the invention, the mixture from step (a) is spray-dried by means of an at least apparatus which uses for spraying at least one spray nozzle, i. one carries out a spray drying or spray drying. The spray drying can be carried out in a spray dryer. Suitable spray dryers are drying towers, for example drying towers with one or more atomizing nozzles and spray dryer with integrated fluidized bed.

Particularly preferred nozzles are two-phase nozzles, in other words nozzles in the interior of which or at the mouth of which substances of different physical state are intensively mixed by means of separate accesses.

In order to carry out step (b), it is possible in a variant to compress the mixture obtained in step (a) through one or more spray devices, for example through one or more nozzles or into a hot air stream or into a hot inert gas stream or hot burner exhaust gases wherein the hot gas stream or the hot inert gas stream or the hot burner exhaust gases may have a temperature in the range of 90 to 500 ° C. As a result, the mixture is dried within a fraction of a second or within a few seconds to a dry material, which is preferably obtained as a powder. The resulting powder may have a certain residual moisture, for example in the range of 500 ppm to 10 wt .-%, preferably in the range of 1 to 8 wt .-%, particularly preferably in the range of 2 to 6 wt .-%.

In a preferred embodiment, the temperature of the hot air stream or of the hot inert gas stream or of the hot burner exhaust gas in step (b) is selected to be above the temperature in step (a).

In one embodiment of the present invention, the hot air stream or the hot inert gas stream or the hot burner exhaust gases flow in the direction of the introduced mixture from step (a) (DC method). In another embodiment of the present invention, the hot air stream or hot inert gas stream flows the hot burner exhaust gases in the direction opposite to the introduced mixture from step (a) (countercurrent process). The spraying device is preferably located at the upper part of the spray dryer, in particular the spray tower. The dry material obtained in step (b) can be separated off after the actual spray drying by a separator, for example a cyclone from the hot air stream or hot inert gas stream or from the hot burner exhaust gases. In another embodiment, the dry material obtained in step (b) is separated from the hot air stream or hot inert gas stream or from the hot burner exhaust gases after the actual spray drying by one or more filters.

The dry material obtained in step (b) may, for example, have an average particle diameter (D50, weight average) in the range from 1 to 50 μm. It is preferred if the average particle diameter (D90, volume average) is up to 120 μιη, more preferably up to 50 μιη and most preferably up to 20 μιη.

Step (b) can be carried out batchwise (batchwise) or else continuously.

In the subsequent step (c), the dry material from step (b) is treated thermally, specifically at temperatures in the range from 350 to 1200 ° C., preferably from 400 to 900 ° C.

In one embodiment of the present invention, the thermal treatment in step (c) is carried out in a temperature profile with two to five, preferably with three or four zones, wherein each zone of the temperature profile preferably has a higher temperature than the preceding one. For example, in a first zone, a temperature in the range of 350 to 550 ° C can be set, in a second zone in the range of 450 to 750 ° C, the temperature being higher than in the first zone. If you wish to introduce a third zone, you can thermally treat in the third zone at 700 to 1200 ° C, but in any case at a temperature higher than in the second zone. The zones can be created, for example, by setting certain heating zones.

If one wishes to carry out step (c) intermittently, one can set a temporal temperature profile, ie. H. For example, it is first treated at 350 to 550 ° C, then at 450 to 750 ° C, the temperature being higher than in the first phase. If you wish to introduce a third phase, you can treat in the third phase at 700 to 1200 ° C, but in any case at a temperature that is higher than in the second phase. The thermal treatment according to step (c) can be carried out, for example, in a rotary kiln, a pendulum reactor, a muffle open, a calcination furnace, a, a quartz ball furnace or a push-through furnace (English roller hearth kiln or RHK).

The thermal treatment according to step (c) can be carried out, for example, in a weakly oxidizing atmosphere, preferably in an inert or reducing atmosphere. In the context of the present invention, weakly oxidizing means an oxygen-containing nitrogen atmosphere which contains up to 2% by volume of oxygen, preferably up to 1% by volume. Examples of inert atmosphere are noble gas, in particular argon atmosphere, and nitrogen atmosphere. Examples of a reducing atmosphere are nitrogen or noble gases containing 0.1 to 10% by volume of carbon monoxide, hydrocarbon, ammonia or hydrogen. Further examples of a reducing atmosphere are air or air enriched with nitrogen or with carbon dioxide, each containing more than one mole of carbon monoxide, rather than oxygen.

In one embodiment of the present invention, step (c) may be carried out over a period in the range of 1 minute to 24 hours, preferably in the range of 10 minutes to 3 hours. The inventive method can be carried out without much dust. By the method according to the invention electrode materials with excellent Theological properties are accessible, which are suitable as electrode materials and can be processed very well. For example, they can be processed into pastes with good rheological properties, such pastes have a lower viscosity.

Another object of the present invention are electrode materials containing

(H) carbon in an electrically conductive modification and

(I) at least one compound of general formula (I), Lix (M (i- _y) Fe _y ) aPOz (I) in short also called transition metal compound (I), wherein the variables are defined as follows:

M is selected from Sc, Ti, V, Cr, Mn, Co, Ni, Mg, Al, Nb, W, Mo, Cu and Zn, preferably selected from Sc, V, Mn, Ni and Co.

x is a number in the range of 0.1 to 4, preferably at least 0.8, particularly preferably 1 to

3, most preferably 1, 5 to 2.5;

y is a number in the range of 0.1 to 1, preferably at least 0.2;

z is a number in the range of 2 to 6, preferably 3 to 5, particularly preferably 2.5 to 4.5, and very particularly preferably z = 4;

a is a number in the range of 0.1 to 4, preferably 0.2 to 2, more preferably 0.5 to 1.5, and most preferably a = 1. wherein carbon (H) is present in the pores of secondary particles of transition metal compound (I) or in the form of particles which can contact particles of transition metal compound (I) at one point or one or more particles of carbon (H). In one embodiment of the present invention, in transition metal compound (I), the variables

x is a number in the range of 0.8 to 3,

y is a number in the range of 0.01 to 1,

z is a number in the range of 3 to 5,

a is a number in the range of 0.2 to 2.0

and the remaining variables as defined above.

Very particular preference is given to corresponding transition metal compound (I) of the formula LiFeP0 ₄ or LiFeo, 2Mn ₀ , 8P0 ₄ or LiFe ₀ , 5Mn ₀ , 5PO ₄ or LiFe ₀ , 7Mn ₀ , 3PO ₄ .

Elements such as potassium and sodium are ubiquitous, at least in trace amounts. In the context of the present invention, therefore, amounts of sodium or potassium in the range of 0.1 wt .-%, based on total transition metal compound (I), or less should not be considered as a component of transition metal compound (I).

In one embodiment of the present invention, transition metal compound (I) may be doped or contaminated with one or more other metal cations, for example with alkaline earth metal cations, in particular with Mg ²⁺ or Ca ²⁺ , or with alkali metal cations, in particular with K ⁺ or Na ⁺ .

In one embodiment of the present invention, electrode material according to the invention has a BET surface area in the range from 10 to 40 m ² / g, determined in accordance with DIN 66131. In one embodiment of the present invention, electrode material according to the invention has a monomodal pore diameter distribution. In another embodiment of the present invention, electrode material according to the invention has a bimodal pore diameter distribution. In another embodiment of the present invention, electrode material according to the invention has a multimodal pore diameter distribution.

Carbon in an electrically conductive modification (H), or carbon for short, is, for example, carbon black, graphite, graphene, carbon nanotubes, expanded graphites, intercalated graphites or activated carbon. In one embodiment of the present invention, electrically conductive carbonaceous material is carbon black. Carbon black may, for example, be selected from lampblack, furnace black, flame black, thermal black, acetylene black, carbon black and furnace carbon black. Carbon black may contain impurities, for example hydrocarbons, in particular aromatic hydrocarbons, or oxygen-containing compounds or oxygen-containing groups, for example OH groups, epoxide groups, carbonyl groups and / or carboxyl groups. Furthermore, sulfur or iron-containing impurities in carbon black are possible. In one variant, electrically conductive, carbonaceous material is partially oxidized carbon black. Partially oxidized carbon black, also referred to as activated carbon black, contains oxygen-containing groups such as, for example, OH groups, epoxide groups, carbonyl groups and / or carboxyl groups.

In one embodiment of the present invention, electrically conductive carbonaceous material is carbon nanotubes. Carbon nanotubes (carbon nanotubes, short CNT or English carbon nanotubes), for example single-walled carbon nanotubes (SW CNT) and preferably multi-walled carbon nanotubes (MW CNT), are known per se. A process for their preparation and some properties are described, for example, by A. Jess et al. In Chemie Ingenieur Technik 2006, 78, 94-100.

In one embodiment of the present invention, carbon nanotubes have a diameter in the range of 0.4 to 50 nm, preferably 1 to 25 nm.

In one embodiment of the present invention, carbon nanotubes have a length in the range of 10 nm to 1 mm, preferably 100 nm to 500 nm. Carbon nanotubes can be prepared by methods known per se. For example, one can use a volatile carbon-containing compound such as methane or carbon monoxide, acetylene or ethylene, or a mixture of volatile carbon-containing compounds such as synthesis gas in the presence of one or more reducing agents such as hydrogen and / or another gas such as nitrogen decompose. Another suitable gas mixture is a mixture of carbon monoxide with ethylene. Suitable decomposition temperatures are, for example, in the range from 400 to 1000.degree. C., preferably from 500 to 800.degree. Suitable pressure conditions for the decomposition are, for example, in the range of atmospheric pressure to 100 bar, preferably up to 10 bar. Single- or multi-walled carbon nanotubes can be obtained, for example, by decomposition of carbon-containing compounds in the arc, in the presence or absence of a decomposition catalyst.

In one embodiment, the decomposition of volatile carbon-containing compound or carbon-containing compounds in the presence of a decomposition catalyst, for example Fe, Co or preferably Ni.

In the context of the present invention, graphene is understood as meaning almost ideal or ideally two-dimensional hexagonal carbon crystals, which are constructed analogously to individual graphite layers. They can be one C-atom layer thick or only a few, for example 2 to 5 C-atom layers. Graphene can be prepared by exfoliation or by delamination of graphite. In the context of the present invention, intercalated graphites are understood to mean not completely delaminated graphites which contain other atoms, ions or compounds intercalated between the hexagonal C atom layers. For example, alkali metal ions, S0 ₃ , nitrate or acetate can be incorporated. The production of intercalated graphites (also: expandable graphites) are known, see for example Rüdorff, Z. anorg. Gen. Chem. 1938, 238 (1), 1. Intercalated graphites can be prepared, for example, by thermal expansion of graphite.

Expanded graphites can be obtained, for example, by expansion of intercalated graphites, see, e.g. McAllister et al. Chem. Mater. 2007, 19, 4396-4404.

In one embodiment of the present invention, the weight ratio of transition metal compound (I) and carbon (H) is in the range from 200: 1 to 5: 1, preferably 100: 1 to 10: 1, more preferably 100: 1, 5 to 20: 1 ,

Carbon (H) exists in the pores of secondary particles of transition metal compound (I) or in the form of particles which can contact particles of transition metal compound (I) at a point or one or more particles of carbon (H). Carbon (H) is not present as a coating of secondary particles of transition metal compound (I), neither as a complete coating nor as a partial coating. Particles of carbon (H) do not contact secondary particles of transition metal compound (I) beyond edges. In one embodiment of the present invention, carbon (H) and transition metal compound (I) coexist in discrete particles which contact each other point-wise or not at all.

The above-described morphology of carbon (H) and transition metal compound (I) can be understood, for example, by light microscopy, transmission electron microscopy

(TEM) or scanning electron microscopy (SEM) prove, in addition, for example, by X-ray on the diffraction pattern.

In one embodiment of the present invention, primary particles of compound (I) have an average diameter in the range from 1 to 2000 nm, preferably 10 to 1000 nm, particularly preferably 50 to 500 nm. The mean primary particle diameter can be determined, for example, by SEM or TEM.

In one embodiment of the present invention, transition metal compound (I) is present in the form of particles which have an average particle diameter in the range from 1 to 150 μm (d50) and can be present in the form of agglomerates (secondary particles). Before- zugt are average particle diameter (d50) in the range of 2 to 50 μιη, more preferably in the range of 4 to 30 μιη.

In one embodiment of the present invention, transition metal compound (I) is in the form of particles which have an average pore diameter in the range from 0.05 μm to 2 μm and which can be present in agglomerates. The average pore diameter can be determined, for example, by mercury porosimetry, for example according to DIN 66133.

In one embodiment of the present invention, transition metal compound (I) is present in the form of particles which have an average pore diameter in the range of 0.05 μm to 2 μm and exhibit a mono- or multimodal course of the intrusion volumes in the range 100-0.001 μm and thereby preferably have a pronounced maximum in the range between 10 μιτι and 1 μιη, preferably two distinct maxima, one each between 10 and 1 and between 1 and 0.1 μιη.

In one embodiment of the present invention, carbon (H) has an average primary particle diameter in the range of 1 to 500 nm, preferably in the range of 2 to 100 nm, more preferably in the range of 3 to 50 nm, most preferably in the range of 4 to 10 nm.

Particle diameters in the context of the present invention are preferably given as volume average, determinable for example by laser diffraction on dispersions according to the Fraunhofer or Mie theory. In one embodiment of the present invention, electrode material according to the invention additionally contains at least one binder (J), for example a polymeric binder.

Suitable binders (J) are preferably selected from organic (co) polymers. Suitable (co) polymers, ie homopolymers or copolymers, can be selected, for example, from anionic, catalytic or free-radical (co) polymerization

(Co) polymers, in particular of polyethylene, polyacrylonitrile, polybutadiene, polystyrene, and copolymers of at least two comonomers selected from ethylene, propylene, styrene, (meth) acrylonitrile and 1, 3-butadiene. In addition, polypropylene is suitable. Furthermore, polyisoprene and polyacrylates are suitable. Particularly preferred is polyacrylonitrile.

In the context of the present invention, polyacrylonitrile is understood to mean not only polyacrylonitrile homopolymers, but also copolymers of acrylonitrile with 1,3-butadiene or styrene. Preference is given to polyacrylonitrile homopolymers. In the context of the present invention, polyethylene is understood to mean not only homo-polyethylene, but also copolymers of ethylene which contain at least 50 mol% of ethylene in copolymerized form and up to 50 mol% of at least one further comonomer, for example example, α-olefins such as propylene, butylene (1-butene), 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-pentene, also isobutene, vinyl aromatics such as styrene, continue

(Meth) acrylic acid, vinyl acetate, vinyl propionate, Ci-Cio-alkyl esters of (meth) acrylic acid, in particular methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, further maleic acid, maleic anhydride and itaconic. Polyethylene may be HDPE or LDPE.

In the context of the present invention, polypropylene is understood to mean not only homo-polypropylene but also copolymers of propylene which contain at least 50 mol% of propylene polymerized and up to 50 mol% of at least one further comonomer, for example ethylene and α-propylene. Olefins such as butylene, 1-hexene, 1-octene, 1-decene, 1-dodecene and 1-pentene. Polypropylene is preferably isotactic or substantially isotactic polypropylene.

In the context of the present invention, polystyrene is understood to mean not only homopolymers of styrene, but also copolymers with acrylonitrile, 1,3-butadiene, (meth) acrylic acid, C 1 -C 10 -alkyl esters of (meth) acrylic acid, divinylbenzene, in particular 1, 3. Divinylbenzene, 1, 2-diphenylethylene and a-methylstyrene.

Another preferred binder (J) is polybutadiene.

Other suitable binders (J) are selected from polyethylene oxide (PEO), cellulose, carboxymethyl cellulose, polyimides and polyvinyl alcohol.

In one embodiment of the present invention, binders (J) are selected from those (co) polymers which have an average molecular weight M _w in the range from 50,000 to 1,000,000 g / mol, preferably up to 500,000 g / mol. Binders (J) may be crosslinked or uncrosslinked (co) polymers.

In a particularly preferred embodiment of the present invention, binders (J) are selected from halogenated (co) polymers, in particular from fluorinated (co) polymers. Halogenated or fluorinated (co) polymers include those (co) polymers which contain at least one (co) monomer in copolymerized form which has at least one halogen atom or at least one fluorine atom per molecule, preferably at least two halogen atoms or at least two fluorine atoms per molecule.

Examples are polyvinyl chloride, polyvinylidene chloride, polytetrafluoroethylene, polyvinylidene fluoride (PVdF), tetrafluoroethylene-hexafluoropropylene copolymers, vinylidene fluoride-hexafluoropropylene copolymers (PVdF-HFP), vinylidene fluoride-tetrafluoroethylene copolymers, perfluoroalkylviny- lether copolymers, ethylene-tetrafluoroethylene copolymers, vinylidene fluoride-chlorotrifluoroethylene copolymers and ethylene-chlorofluoroethylene copolymers.

Suitable binders (J) are in particular polyvinyl alcohol and halogenated (co) polymers, for example polyvinyl chloride or polyvinylidene chloride, in particular fluorinated (co) polymers such as polyvinyl fluoride and in particular polyvinylidene fluoride and polytetrafluoroethylene.

In one embodiment of the present invention, electrode material according to the invention contains:

in the range from 60 to 98% by weight, preferably from 70 to 96% by weight of transition metal compound (I), in the range from 1 to 25% by weight, preferably from 2 to 20% by weight, of carbon (H),

in the range of 1 to 20 wt .-%, preferably 2 to 15 wt .-% binder (J).

Inventive electrode materials can be used well for the production of electrochemical cells. For example, they can be processed into pastes with good theological properties.

Another object of the present invention are electrochemical cells prepared using at least one electrode according to the invention. A further subject of the present invention are electrochemical cells containing at least one electrode according to the invention.

Another aspect of the present invention is an electrode containing at least one transition metal compound (I), carbon (H) and at least one binder (J).

Compound of the general formula (I), carbon (H) and binder (J) are described above.

The geometry of electrodes according to the invention can be chosen within wide limits. It is preferred to design electrodes according to the invention in thin films, for example in films having a thickness in the range from 10 μm to 250 μm, preferably from 20 to 130 μm.

In one embodiment of the present invention, electrodes according to the invention comprise a foil, for example a metal foil, in particular an aluminum foil, or a polymer foil, for example a polyester foil, which may be untreated or siliconized.

Another object of the present invention is the use of electrode materials according to the invention or electrodes according to the invention in electrochemical cells. A further subject of the present invention is a process for the production of electrochemical cells using electrode material according to the invention or electrodes according to the invention. Another object of the present invention are e- electrochemical cells containing at least one electrode material according to the invention or at least one electrode according to the invention.

Electrochemical cells according to the invention definitely serve as cathodes in electrochemical cells according to the invention. Electrochemical cells according to the invention contain a counterelectrode which is defined as an anode in the context of the present invention and which can be, for example, a carbon anode, in particular a graphite anode, a lithium anode, a silicon anode or a lithium titanate anode. Electrochemical cells according to the invention may be, for example, batteries or accumulators.

Electrochemical cells according to the invention may comprise, in addition to the anode and the electrode according to the invention, further constituents, for example conductive salt, nonaqueous solvent, separator, current conductor, for example of a metal or an alloy, furthermore cable connections and housing.

In one embodiment of the present invention, electrical cells according to the invention contain at least one non-aqueous solvent which may be liquid or solid at room temperature, preferably selected from polymers, cyclic or non-cyclic ethers, cyclic and non-cyclic acetals and cyclic or not cyclic organic carbonates.

Examples of suitable polymers are in particular polyalkylene glycols, preferably P0IV-C1-C4-alkylene glycols and in particular polyethylene glycols. Polyethylene glycols may contain up to 20 mol% of one or more C 1 -C 4 -alkylene glycols in copolymerized form. Preferably, polyalkylene glycols are polyalkylene glycols double capped with methyl or ethyl. The molecular weight M _w of suitable polyalkylene glycols and especially of suitable polyethylene glycols may be at least 400 g / mol.

The molecular weight M _w of suitable polyalkylene glycols and in particular of suitable polyethylene glycols may be up to 5,000,000 g / mol, preferably up to 2,000,000 g / mol

Examples of suitable non-cyclic ethers are, for example, diisopropyl ether, di-n-butyl ether, 1, 2-dimethoxyethane, 1, 2-diethoxyethane, preference is 1, 2-dimethoxyethane.

Examples of suitable cyclic ethers are tetrahydrofuran and 1,4-dioxane. Examples of suitable non-cyclic acetals are, for example, dimethoxymethane, diethoxymethane, 1,1-dimethoxyethane and 1,1-diethoxyethane.

Examples of suitable cyclic acetals are 1, 3-dioxane and in particular 1, 3-dioxolane.

Examples of suitable non-cyclic organic carbonates are dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate.

Examples of suitable cyclic organic carbonates are compounds of the general formulas (I I) and (II I)

in which R ³ , R ⁴ and R ^{5 may be} identical or different and selected from hydrogen and C 1 -C 4 -alkyl, for example methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec. Butyl and tert-butyl, preferably R ⁴ and R ^{5 are} not both tert-butyl.

In particularly preferred embodiments, R ^{3 is} methyl and R ⁴ and R ⁵ are each hydrogen or R ⁵ , R ³ and R ⁴ are each hydrogen.

Another preferred cyclic organic carbonate is vinylene carbonate, formula (IV).

Preferably, the solvent or solvents are used in the so-called anhydrous state, i. with a water content in the range of 1 ppm to 0.1 wt .-%, determined for example by Karl Fischer titration.

Inventive electrochemical cells also contain at least one conductive salt. Suitable conductive salts are in particular lithium salts. Examples of suitable lithium salts are LiPF _6, LiBF _4, L1CIO4, LiAsF _6, L1CF3SO3, LiC (CnF ₂ n ₊ IS0 ₂₎ 3, lithium imides such as LiN (CnF ₂ n ₊ IS0 ₂₎ 2, where n is an integer ranging from 1 to 20; LiN (SO 2 F) 2, Li 2 SiF 6, LiSbF 2 O, LiAICU, and salts of the general formula (C _n F 2n + i SO 2) mYLi, where m is defined as follows:

m = 1, when Y is selected from oxygen and sulfur,

m = 2 when Y is selected from nitrogen and phosphorus, and

m = 3 when Y is selected from carbon and silicon.

Preferred conducting salts are selected from LiC (CF ₃ SO ₂ ) 3, LiN (CF ₃ SO ₂ ) 2, LiPF ₆ , LiBF ₄ ,

L1CIO4, and particularly preferred are LiPFβ and LiN (CF3SC> 2) 2.

In one embodiment of the present invention, electrochemical cells according to the invention contain one or more separators, by means of which the electrodes are mechanically separated. Suitable separators are polymer films, in particular porous polymer films, which are unreactive with respect to metallic lithium. Particularly suitable materials for separators are polyolefins, in particular film-shaped porous polyethylene and film-shaped porous polypropylene.

Polyolefin separators, particularly polyethylene or polypropylene, may have a porosity in the range of 35 to 45%. Suitable pore diameters are for example in the range from 30 to 500 nm.

In another embodiment of the present invention, separators may be selected from inorganic particle filled PET webs. Such separators may have a porosity in the range of 40 to 55%. Suitable pore diameters are, for example, in the range from 80 to 750 nm.

Electrochemical cells according to the invention furthermore contain a housing which can have any shape, for example cuboidal or the shape of a cylindrical disk. In one variant, a metal foil developed as a bag is used as the housing.

Inventive electrochemical cells provide a high voltage and are characterized by a high energy density and good stability.

Electrochemical cells according to the invention can be combined with one another, for example in series connection or in parallel connection. Series connection is preferred.

Another object of the present invention is the use of electrochemical cells according to the invention in devices, in particular in mobile devices. Examples of mobile devices are vehicles, for example automobiles, two-wheelers, aircraft or watercraft, such as boats or ships. Other examples of mobile devices are those that you move yourself, such as computers, especially laptops, phones, or electrical tools, for example in the field of construction, in particular drills, cordless screwdrivers or cordless tackers.

The use of electrochemical cells in devices according to the invention offers the advantage of a longer running time before reloading. If one wanted to realize an equal running time with electrochemical cells with a lower energy density, then one would have to accept a higher weight for electrochemical cells.

The invention will be explained by working examples.

working examples

Preparation of an electrode material step (a.1)

Starting materials:

12.14 kg a-FeOOH (A.1)

5.83 kg of LiOH ^■ H ₂ O (C.1)

5.66 kg H ₃ P0 ₃ (B.1)

7.89 kg H ₃ P0 ₄ (B.2)

2.17 kg lactose (D.1)

1, 96 kg thickness (D.2)

First, 133.5 l of distilled water were placed in a 200 liter double-walled stirred vessel with an anchor stirrer and heated to 58.5 ° C. Subsequently, the LiOH was dissolved ^■ H2O (C.1) therein, and then the iron compound (A.1) was added. Thereafter, (B.1) and (B.2) were added. The temperature rose to 78 ° C. Then you gave (D.1) and (D.2). The mixture was stirred at 75 ° C. for 16 hours (pH 5). A yellow suspension was obtained. Step (b.1)

The solution from step (a.1) was sprayed in a spray tower by program under air. The hot air flow had a temperature of 330 ° C at the entrance, at the exit still 1 10 ° C. The dryer was operated with 350 kg / h of drying gas and 33 kg / h of nozzle gas (sputtering gas) with an atomization pressure of 3.5 bar.

A yellow free-flowing powder with a residual moisture content of 8% was obtained. It was in the form of particles whose diameter (D50) was 19 μm. SEM images showed spherical agglomerates of yellow powder held together by the organic components lactose and starch.

Step (c.1) The yellow powder from step (b.1) was thermally treated in a 2 liter steel laboratory rotary kiln under an N 2 atmosphere. The 2-liter steel laboratory rotary kiln had three temperature zones and rotated at a speed of 10 revolutions / min. The temperature in zone 1 was 450 ° C., in zone 2 the temperature was 725 ° C. and in zone 3 it was 775 ° C. The mean residence time was one hour. After the thermal treatment was allowed to cool to room temperature. Inventive electrode material containing transition metal compound (1.1) and carbon (H.1) was obtained. Carbon (H.1) and transition metal compound (1.1) were present in discrete particles, as shown by light microscopy, which did not touch at all or only at a single point. Diameter (D50): 17.2 μιτι.

The tamped density of the sieve fraction <32μιτι was 0.92 g / ml.

II. Production of Electrochemical Cells According to the Invention

Inventive electrode material was processed with a binder (J.1): copolymer of vinylidene fluoride and hexafluopropene, as a powder, commercially available as Kynar Flex® 2801 from Arkema, Inc., as follows.

To determine the electrochemical data of the electrode materials, 8 g of electrode material according to the invention from step (c.1) and 1 g (J.1) with the addition of 1 g of N-methylpyrrolidone (NM P) were mixed to form a paste. A 30 μιη thick aluminum foil is coated with the paste described above (active material loading 2.72 mg / cm ² ). After drying, but without compression, at 105 ° C, circular parts of the thus coated aluminum foil (diameter 20 mm) were punched out. Electrochemical cells were prepared from the electrodes thus obtained. As the electrolyte, a 1 mol / l solution of LiPFß in ethylene carbonate / dimethyl carbonate (1: 1 based on mass fractions) was used. The anode of the test cells consisted of a lithium foil, which is in contact with the cathode foil via a separator made of glass fiber paper.

The invention gives electrochemical cells EZ.1.

When cycling electrochemical cells of the invention between 3V and 4V at 25 ° C in 100 cycles (charged / discharged) and charging and discharging currents are 150 mA / g cathode material, one can determine the retention of discharge capacity after 100 cycles.

Inventive electrochemical cells EZ.1 show good cycling stability.

Claims

claims

Process for the production of electrode materials, characterized in that

(a) mixed together:

(A) at least one iron compound in which Fe is in the oxidation state +2 or +3,

(B) at least one phosphorus compound,

(C) at least one lithium compound,

(D) at least one carbon source which may be a separate carbon source or at least one iron compound (A) or phosphorus compound (B) or lithium compound (C),

(E) optionally at least one reducing agent,

(F) optionally at least one metal compound having a metal other than iron,

(G) optionally water or at least one organic solvent,

(c) at least two different temperatures in the range of 350 to

1200 ° C thermally treated.

Process according to Claim 1, characterized in that the carbon source (D) used is a separate carbon source selected from activated carbon, carbon black, carbon black, graphenes, carbides, organic polymers and graphite.

A method according to claim 1, characterized in that at least one salt of iron or lithium with at least one organic acid is used as the carbon source which is equal to at least one iron compound (A) or lithium compound (C).

Method according to one of claims 1 to 3, characterized in that iron compound (A) is selected from Fe (OH) ₃ , FeOOH, ammonium iron citrate, Fe2 <D ₃ , Fe ₃ 0 ₄ , iron acetate, FeS0 ₄ , iron citrate, iron lactate , Iron phosphate, iron phosphonate and iron carbonate.

Method according to one of claims 1 to 4, characterized in that lithium compound (C) is selected from LiOH, Li ₂ C0 ₃ , Li ₂ 0, LiN0 ₃ , Li ₂ S0 ₄ , lithium phosphonates and Li phosphates. 6. The method according to any one of claims 1 to 5, characterized in that one selects phosphorus compound (B) from H ₃ P0 ₄ , H ₃ P0 ₃ and salts and esters of the abovementioned acids. Method according to one of claims 1 to 6, characterized in that one carries out the thermal treatment in step (c) in an inert or a reducing atmosphere.

Method according to one of claims 1 to 6, characterized in that one carries out the thermal treatment in step (c) in an oxidizing atmosphere.

Method according to one of claims 1 to 8, characterized in that one selects metal compound (F) from compounds of Sc, Ti, V, Cr, Mn, Co, Ni, Mg, Al, Nb, W, Mo, Cu and Zn.

Electrode material containing

(H) carbon in an electrically conductive modification,

(I) at least one compound of general formula (I)

Lix (M _(i-y) Fe _y) APOZ (I) wherein the variables are defined as follows:

M is selected from Sc, Ti, V, Cr, Mn, Co, Ni, Mg, Al, Nb, W, Mo, Cu and Zn, x is a number in the range of 0.1 to 4,

y is a number in the range of 0.1 to 1,

z is a number in the range of 2 to 6,

a is a number in the range of 0.1 to 4, wherein carbon (H) is present in the pores of secondary particles of transition metal compound (I) or in the form of particles, the particles of transition metal compound (I) point or one or more particles of carbon ( H) can contact.

Electrode material according to claim 10, characterized in that (characterized in that the variables are chosen as follows:

x is a number in the range of 0.8 to 3,

y is at least 0.01,

z is a number in the range of 3 to 5,

a is a number in the range of 0.2 to 2,

and that the remaining variables are as defined above.

Electrode material according to claim 10 or 11, characterized in that the variables are chosen as follows:

x is 1,

y is 1, Electrode material according to one of claims 10 to 12, characterized in that carbon (H) has an average particle diameter in the range of 1 to 500 nm.

Electrode material according to one of claims 10 to 13, characterized in that it has a residual moisture in the range of 100 to 5000 ppm.

An electrode material according to any one of claims 10 to 14, characterized in that compound of the general formula (I) is in the form of particles which may be present in agglomerates and have a mean particle diameter in the range of 1 to 150 μιη (d50).

An electrode material according to any one of claims 10 to 15, characterized in that compound of the general formula (I) is in the form of particles having a mean pore diameter in the range of 0.05 μιη to 2 μιτι and which may be present in agglomerates.

Use of electrode materials according to any one of claims 10 to 16 for the production of electrochemical cells.

Electrochemical cells containing at least one electrode material according to one of Claims 10 to 16.

Use of electrochemical cells according to claim 18 in devices.