EP2794472A1

EP2794472A1 - Metal phosphate containing manganese and method for its production

Info

Publication number: EP2794472A1
Application number: EP12809277.2A
Authority: EP
Inventors: Gunnar BÜHLER; Christian Dr. Graf; Andreas Jazdanian; Kilian Schwarz; Michael RAPPHAHN
Original assignee: Chemische Fabrik Budenhiem KG
Current assignee: Chemische Fabrik Budenhiem KG
Priority date: 2011-12-21
Filing date: 2012-12-21
Publication date: 2014-10-29
Also published as: RU2014129527A; MY185281A; WO2013093014A1; JP6097306B2; BR112014012066A2; CN104039693B; CN104039693A; RU2616063C2; JP2015502911A; DE102011056816A1; KR20140110892A; US20150108412A1; US9350020B2; BR112014012066A8; TW201343542A; TWI576312B; IN2014KN00962A; CA2851432A1

Abstract

Monometallic phosphate containing manganese (Mn) of the type Mn₃(PO₄)₂ ⋅ 3 H₂O or mixed metallic phosphate of the type (Mn_x Met_y)₃(PO₄)₂ ⋅ 3 H₂O, wherein x + y = 1 and Met represents one or multiple metals selected from Fe, Co, Ni, Sc, Ti, V, Cr, Cu, Zn, Be, Mg, Ca, Sr, Ba, AI, Zr, Hf, Re, Ru, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, characterised in that the phosphate in the powder x-ray diffraction diagram has peaks at 10.96 ± 0.05, 12.78 ± 0.17, 14.96 ± 0.13, 17.34 ± 0.15, 18.98 ± 0.18, 21.75 ± 0.21, 22.07 ± 0.11, 22.97 ± 0.10, 25.93 ± 0.25, 26.95 ± 0.30, 27.56 ± 0.10, 29.19 ± 0.12, 29.84 ± 0.21, 30.27 ± 0.12, 34.86 ± 0.21, 35.00 ± 0.20, 35.33 ± 0.30, 35.58 ± 0.10, 35.73 ± 0.12, 42.79 ± 0.45, 43.37 ± 0.45, 44.70 ± 0.15 and 44.93 ± 0.20 degree two-Theta, based on CuKα radiation.

Description

Manganese-containing metal phosphates and process for their preparation

Subject of the invention

The invention relates to a new manganese (Mn) containing monometallic phosphate of the type Mn ₃ (P0 ₄ ) ₂ ^■ 3 H ₂ 0 or mixed metallic phosphate of the type (Mn _x Met _y ) ₃ (P0 ₄ ) 2 ^■ 3 H ₂ 0, wherein x + y = 1 and Met represents one or more metals selected from Fe, Co, Ni, Sc, Ti, V, Cr, Cu, Zn, Be, Mg, Ca, Sr, Ba, Al, Zr, Hf, Re , Ru, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. The invention further relates to a process for the preparation of the phosphate and its use.

Background of the invention

Rechargeable Li-ion batteries are widely used energy storage devices, especially in the field of mobile electronics. The cathode materials are lithium metal oxides such as LiCo0 ₂ , LiNi0 ₂ , LiNi |. _x Co _x 0 ₂ and LiMn ₂ 0 ₄ , established. In addition to the oxides, lithium-containing phosphines with olivine structure, such as LiFePO ₄ (LFP), have been developed, which are suitable as cathode materials. These materials are characterized by good performance, high specific capacity and very high stability. In addition, there are other LFP containing lithium phosphates, which are discussed as commercially useful cathode materials, such as LiMnP0 _4, LiCoP0 ₄ or LiNiP0. ₄ In addition, also be mixed-metal compounds of the type LiA _x B _y C _z P0 ₄ ((x + y + z) = 1) will be discussed, such as alloys of LiNiP0 ₄ and LiCoP0 ₄ in the form of LiNi _x Co _x .- | P0 ₄ or LiFe _x Mn- |. _x P0 ₄ . In particular, LiFe _x Mn _y P0 ₄ and LiFe _x Mn _y M _z PO ₄ (LFMP), where M is a metal cation such as Mg, are discussed as suitable compounds for the replacement of pure LiFePO ₄ (LFP) in cathode materials. Due to the higher working voltage of manganese or nickel or cobalt-containing compounds compared to iron-containing olivines, a higher energy storage density can be achieved.

DE 10 2009 001 204 describes a process for the preparation of crystalline iron (III) orthophosphate dihydrate (FOP) with phosphosiderite or metastrengite II crystal structure which, owing to the preparation process and the material properties, works well as precursor compound for the preparation of LFP according to methods described in the literature. WO 97/40541, US Pat. No. 5,910,382 and WO 00/60680 describe the preparation of lithium mixed metal phosphates, with physical mixtures of different metal salts or organometallic compounds being prepared as a rule, which are prepared in a subsequent step using classical methods the solid state synthesis at high temperatures and possibly atmospheric control are calcined. In most cases, the starting compounds are decomposed in such a way that only the desired ions remain to build up the target compound in the reaction system. In order to achieve an ideal isotropic distribution of the various cations in a crystal matrix, in thermal processes, such as calcining, a sufficiently high energy must generally be introduced into the reaction system in order to ensure efficient ion diffusion. In general, an intensive mixing of all raw materials used upstream to reduce the energy and time required. Dry or wet mechanical processes, eg ball mills, are particularly suitable for mixing the raw materials. However, only mechanical mixtures of particles or crystals of different metal salts are obtained in this way. During the subsequent calcination, it must therefore be ensured that the ions required to build up the desired crystal phase diffuse beyond the primary grain boundaries. Usually this requires temperatures above 700 to 800 ° C and calcination times over 15 hours. It is also customary to first heat the physical mixtures at lower temperatures (300-400 ° C.) in order to bring about initial decomposition. Subsequently, these intermediates are then crushed again and mixed thoroughly to achieve any good results in terms of phase purity, crystallinity and homogeneity. The known thermal processes are therefore energy and time consuming.

In addition, particularly high purity requirements are placed on the starting materials used for the production of cathode materials for lithium-ion batteries, since all components and impurities that do not decompose remain in the reaction system and thus in the product. In the decomposition of cations and anions of the metal compounds used as starting materials (eg, NH ₄ ⁺ , C ₂ 0 ₄ ^{2 "} , (CH ₃ ) (CH ₂ ) _n COO ^~ , C0 ₃ ^{2 ~} , etc.) also arise gases , which due to potentially dangerous properties (eg CO, NH ₃ , NO _x , etc.) must be treated consuming in the exhaust stream.

CA 02443725 describes the preparation of UXYPO 4 (X, Y = metal, eg Fe, Mn, etc.) using iron sulfate, manganese sulfate and lithium phosphate, and additionally lithium hydroxide as starting materials, from which initially an unspecified solid mixture is prepared, which is then converted by a calcination step at 300 to 1000 ° C in the desired product. The introduction of certain metals in the form of their sulfates in equimolar amount to the phosphate usually requires that the product be subjected to an intensive washing process in order to reduce the sulfate content to a tolerable level. Sulphate is known to be an undesirable contaminant in lithium-ion batteries due to the corrosive action. However, as a result of an intensive washing process, the product can also be deprived of lithium in a considerable amount since only trilithium orthophosphate has a very low solubility among the lithium orthophosphates. If the product of CA 02443725 undergoes such a washing process, leaching of lithium is to be assumed. However, in CA 02443725 a washing process is not mentioned, which in turn would result in a high sulphate contamination of the product.

In principle, quite homogeneous cation distributions can be achieved by hydro- or solvothermal methods if the solubilities and complex formation constants or the crystal growth factors of the introduced cations and anions can be controlled and adjusted over the course of the reaction in the selected matrix so that only the desired species is formed in isolable form , In many cases, surface-active substances or auxiliaries which promote the formation of a specific crystal phase or growth in a preferred direction, so-called templates which are known to the person skilled in the art, are used to control crystal growth. These processes often work in closed systems beyond the boiling point of the reaction matrix, resulting in very high pressures. This places high demands on the reactor technology. In many cases, however, the products obtained have to be calcined afterwards or additionally in order to ensure the necessary crystallinity. Also, the surface-active adjuvants must be removed quantitatively so as not to cause any negative effects in the subsequent application. This is also achieved by heating, whereby these substances burn or char / soot.

There are also described methods without pressure, wherein the crystallization times of the desired products are always given with several days to weeks. This calls into question the economic efficiency of commercial use. task

The object of the present invention was to provide novel monometallic or mixed-metallic phosphates which are suitable, for example, for the production of cathode materials for lithium-ion batteries, in particular those with which cathode materials with high energy storage densities can be produced, and to provide a method for their production which is comparatively energy-efficient and is easy and with which the phosphates are produced in high purity, so that they are better than the prior art, for example, as precursor compounds (precursors) for the production of lithiated cathode materials for lithium ion batteries better. Description of the invention

The object of the invention is achieved by a manganese (Mn) containing mono-metal phosphate of the type Mn ₃ (P0 ₄₎ ₂ ^■ 3 H ₂ 0 or mixed metal phosphate of the type (Mn _x Met _y) ₃ (P0 ₄₎ 2 ^■ 3 H ₂ O, where x + y = 1 and Met represents one or more metals selected from Fe, Co, Ni, Sc, Ti, V, Cr, Cu, Zn, Be, Mg, Ca, Sr, Ba, Al, Zr, Hf, Re, Ru, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, characterized in that the phosphate in the powder X-ray diffraction pattern peaks at 10, 96 ± 0.05, 12.78 ± 0.17, 14.96 ± 0.13, 17.34 ± 0.15, 18.98 ± 0.18, 21.75 ± 0.21, 22.07 ± 0.11, 22.97 ± 0.10, 25.93 ± 0.25, 26.95 ± 0.30, 27.56 ± 0.10, 29.19 ± 0.12, 29.84 ± 0, 21, 30.27 ± 0.12, 34.86 ± 0.21, 35.00 ± 0.20, 35.33 ± 0.30, 35.58 ± 0.10, 35.73 ± 0.12, 42.79 ± 0.45, 43.37 ± 0.45, 44.70 ± 0.15 and 44.93 ± 0.20 degrees two-theta based on CuKo radiation. The manganese (Mn) -containing phosphate of the present invention has a novel structural type characterized by its peak positions in the powder X-ray diffraction pattern. The new structure type is also referred to herein as "Mn ₃ (P0 ₄ ) ₂ ^■ 3 H ₂ O-structure type". This type of structure is unknown in the literature. It can be-called with the above both as mono-metal phosphate of the type Mn ₃ (P0 ₄₎ ₂ ^■ 3 H ₂ 0, as well as mixed metal phosphate of the type (Mn _x Met _y) ₃ (P0 ₄₎ ₂ ^■ 3 H ₂ 0 obtained characteristic peak positions in the powder X-ray diffraction diagram. The individual peaks, depending on the composition of the metal components, may be subject to slight shifts within an angular range indicated by "±" given in degrees two-theta. The novel structure-type manganese (Mn) -containing phosphate of the present invention preferably has an orthorhombic unit cell with lattice parameters of 13, 2 ± 0.2, 8.6 ± 0.2 and 8.1 ± 0.2 angstrom.

In a preferred embodiment of the invention, the manganese (Mn) -containing phosphate is present as carbon composite and contains 1 to 10 wt .-% carbon, preferably 1.5 to 5 wt .-% carbon, more preferably 1.8 to 4 wt. % Carbon, based on the total weight of phosphate and carbon.

Such phosphate-carbon composites are obtained by adding a carbon source during the preparation of the phosphate according to the invention, which is described in more detail below in connection with the process according to the invention. The inclusion of carbon in the product according to the invention allows an electrically conductive equipment of the material per se and / or the producible from the material products, for example, cathode materials for lithium ion batteries. Due to the amount and type of carbon source added in the preparation, the resulting carbon content and thus the conductivity can be adjusted freely within certain limits. One Too high a carbon content has the disadvantage of reducing the maximum possible amount of cathode active material in later use in lithium ion batteries. At a carbon content below 1 wt .-%, a sufficient conductivity increase is no longer achieved. In a further preferred embodiment of the invention, the manganese (Mn) -containing phosphate has a platelet-shaped morphology, preferably with a platelet thickness (= smallest spatial extent) in the range of 10 to 100 nm, more preferably in the range of 20 to 70 nm, most preferably in Range of 30 to 50 nm. The platelet-shaped morphology preferred according to the invention has particular advantages, for example when using the phosphate according to the invention for the production of lithiated (Li-containing) cathode material for Li-ion batteries. The platelet form with nanoscale platelet thickness of the primary crystallites ensures the lowest possible diffusion distances and diffusion times during lithiation via simple and inexpensive calcination processes. The ideally isotropic distribution of the metal ions present in the material according to the invention also reduces the necessary calcination temperatures and calcining times, since no diffusion of matrix ions across grain boundaries is necessary. The defined crystal structure ensures clear and reproducible reaction paths during calcination and in the production of cathode materials. In a further preferred embodiment of the invention, the manganese (Mn) is containing phosphate is a mixed metal phosphate of the type (Mn _x Met _y) ₃ (P0 ₄₎ 2 ^■ 3 H ₂ 0, in which the ratio of Mn: (Mn + Met) = x: (x + y) 0.15, preferably> 0.4, more preferably> 0.5. The ratio of Mn: (Mn + Met) denotes the atomic ratio of manganese to the sum of all metals included in the present invention including manganese. In the formula notation used for the mixed-metal phosphate according to the invention (Mn _x Met _y ) ₃ (PO ₄ ) 2 ^.3H ₂ 0 m with x + y = 1, the ratio of Mn: (Mn + Met) can also be given by x: ( x + y). In a monometallic phosphate according to the invention, the ratio x: (x + y) = 1, since in this case y = 0. At too low a manganese content in the mixed-metal phosphate of the new "Mn ₃ (P0 ₄₎ ₂ ^■ 3 H ₂ 0-structure type" can not be obtained.

The present invention also includes a method for preparing a manganese (Mn) containing monometallic phosphate type Mn ₃ (P0 ₄₎ ₂ ^■ a H ₂ 0 or mixed-metal phosphate of the type (Mn _x Met _y) ₃ (P0 ₄₎ ₂ ^■ a H ₂ O, where x + y = 1, a = 0 to 9 and Met represents one or more metals selected from Fe, Co, Ni, Sc, Ti, V, Cr, Cu, Zn, Be, Mg, Ca, Sr, Ba, Al, Zr, Hf, Re, Ru, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, the process being characterized in that you

a) preparing an aqueous solution (I) which contains at least divalent manganese cations (Mn ²⁺ ) and optionally one or more of the metals Fe, Co and / or Ni as divalent cations, by oxidic metal (II) -, metal (III) and / or metal (IV) compounds or mixtures thereof or compounds having mixed oxidation states selected from Hydroxides, oxides, oxide hydroxides, oxide hydrates, carbonates and hydroxide carbonates of at least one of Mn, Fe, Co and / or Ni together with the elemental forms or alloys of at least one of Mn, Fe, Co and / or Ni in a phosphoric acid containing aqueous medium and the oxidic metal compounds fertilize with the elemental forms or alloys of the metals (in a redox reaction) to the bivalent metal ions, wherein at least one of the oxide metal compounds and / or at least one of the elemental forms or alloys of metal comprises manganese,

b) separating any solids present from the phosphoric acid aqueous solution (I), c) if the phosphate is a mixed-metal phosphate and, in addition to the metals introduced into the solution in step a), contains further metals selected under Met, the aqueous solution (I) further at least one compound of at least one of the metals Met in the form of an aqueous solution or as a solid in the form of a salt, wherein the at least one compound is preferably selected from hydroxides, oxides, oxide hydroxides, oxide hydrates, carbonates, hydroxide carbonates, carboxylates, sulfates, chlorides or nitrates of the metals is selected,

d) providing a phosphoric acid solution prepared by neutralization with an aqueous alkali hydroxide solution or a prepared from an aqueous solution of one or more Alkaliphosphate template solution (II) having a pH of 5 to 8, e) the aqueous solution (I) to the Added to template solution (II) and simultaneously a basic aqueous alkali metal hydroxide solution so metered that the pH of the resulting reaction mixture in the range of 5 to 8, preferably 6 to 7, is maintained, wherein the phosphate of the type Mn ₃ (P0 ₄ ) ₂ ^■ a H ₂ O or (Mn _x Met _y ) ₃ (PO ₄ ) 2 ^■ a H ₂ O is precipitated,

f) separating the precipitated phosphate from the reaction solution.

The metals introduced into the solution (I) in step a) are also referred to herein as "main metals." The main metals comprise at least manganese (Mn) and optionally Fe, Co and / or Ni which are optionally added to the solution in step (c). I) introduced metals selected from Fe, Co, Ni, Sc, Ti, V, Cr, Cu, Zn, Be, Mg, Ca, Sr, Ba, Al, Zr, Hf, Re, Ru, La, Ce, Pr , Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu are also referred to herein as "doping metals". Also further manganese (Mn) can be introduced in step c). The doping metals may be in the form of the divalent metal ions in the solution, but they may also be in the form of the trivalent or tetravalent metal ions in the solution. Some of the doping metals are preferably in the trivalent form. If, for example, the phosphate according to the invention is further processed into a cathode material, then these non-divalent metal ions constitute quasi-impurities in the structure, which may advantageously influence the performance of the cathode material.

The process according to the invention for producing a monometallic or mixed-metal phosphate is simple and inexpensive compared to the prior art. Another advantage of the method according to the invention is that the aqueous phosphoric acid solution (I) only contains the desired metal cations and exclusively or predominantly phosphate anions or phosphoric acid. An expensive removal of foreign anions, such as sulfates, nitrates, chlorides or others, in the further course of the preparation of the products according to the invention is therefore not required. If doping metals, for example in the form of their sulfates, nitrates or chlorides, are introduced in stage c) of the process according to the invention, this takes place in small amounts which are still acceptable in the product to be produced and do not adversely affect the product properties or only to an acceptable extent. The phosphates according to the invention thus have a high purity, which makes them particularly suitable, for example, for the preparation of lithiated cathode materials. The lithiation can be carried out by a simple thermal reaction step (calcining), in which case a suitable lithium salt must be added depending on the type of phosphate material.

With the method according to the invention an extremely flexible reaction principle is available with which a multiplicity of phosphate systems of the type described herein can be represented, for example (pseudo) binary, (pseudo) ternary and (pseudo) quaternary systems.

The process according to the invention offers the possibility, by suitable choice of the precipitation conditions, such as pH, concentrations, temperature, etc., of certain material parameters, such as crystal phase and cation distribution, morphology, crystallite and secondary particle size and the chemical purity of the resulting products check. Preference is given to the products described above with platelet-shaped morphology, which have a uniform crystal phase and an isotropic distribution of the cations.

In the first reaction stage of the process according to the invention, the oxidic metal (II), metal (III) and / or metal (IV) compounds are reacted with elemental metal or alloys in phosphoric acid aqueous medium in a redox reaction to form the divalent metal ions. The course of the described redox reaction between the elemental metals and the oxidic components depends on their respective specific surface areas, since the electron transfer takes place at the interface. As a competing side reaction to the transition of electrons from the elemental metal forms on the oxidic metal forms, the formation of hydrogen gas is taken into account. This leads to the electron transfer from the elemental metal forms to protons with the formation of radicals, which form hydrogen gas by radical combination. The particle sizes of the elemental and oxidic metal forms used should therefore be matched to suppress the side reaction and to take maximum advantage of the dissolution of the inexpensive oxide metal mold. Generally, the finer the elemental metal form, the more likely the side reaction is favored if the oxic form does not provide a sufficiently high active surface area.

Depending on the composition of the reaction solution, unreacted components may remain as solid residues in the solution. If in the resulting reaction solution still solids are contained, they are preferably separated from the phosphoric acid aqueous solution. The separation of solids can be carried out by any suitable known methods for the separation of liquids and solids, for example filtration, centrifugation, sedimentation etc.

If the phosphate to be prepared according to the invention is a mixed-metal phosphate and, in addition to the metals introduced into the solution in step a), contains further metals selected under Met, the aqueous solution (I) is added to the initial solution (II) in step e) before being metered. at least one compound of at least one of metals selected under Met, optionally also manganese, in the form of an aqueous solution or as a solid in the form of a salt, said at least one compound preferably among hydroxides, oxides, oxide hydroxides, oxide hydrates, carbonates, hydroxide carbonates , Carboxylates, sulfates, chlorides or nitrates of the metals. The addition of these doping metals is expediently carried out in stage c) of the process after any solids present have been separated off from the phosphoric acid aqueous solution (I). Alternatively, the described addition of the doping metals can also be carried out immediately after the preparation of the solution (I) in stage a) and before the separation of any solids present. The separation of optionally contained solids then takes place after the addition of the doping metals. By adding suitable metal salts (doping metals) in the form mentioned, the desired metal content or the ratio of the metals to one another in the phosphate to be produced can be set very precisely. This is especially true for metals that are used in relatively small quantities. Expediently, metal compounds should be introduced which do not introduce any interfering anions into the mixture in the further course of the process in order to ensure the highest degree of purity of the product. These are, in particular, hydroxides, oxides, oxide hydroxides, oxide hydrates, carbonates and hydroxide carbonates which react or decompose to form water under the prevailing acidic conditions. If necessary, buffers familiar to those skilled in the art can be used to prevent undesirable premature or uncontrolled precipitation. Carboxylates are likewise suitable, since the proportions of organic acids remaining in the mixture generally decompose on later calcination of the products. The addition of the metals in the form of their sulfates, chlorides or nitrates may also be suitable for dopants, if the content of sulfates, chlorides or nitrates in the product does not exceed certain limits which are still considered acceptable for the particular application. The template solution (II) for the subsequent precipitation of the phosphates according to the invention is likewise a phosphate solution having a pH in the range of 5 to 8 buffered. The initial solution is prepared either from an aqueous phosphoric acid solution by neutralization with an aqueous alkali metal hydroxide solution or directly from an aqueous solution of one or more alkali metal phosphates. For the precipitation of the phosphates according to the invention, the aqueous solution (I) is added to the pre-treatment solution (II). Due to the low pH of the phosphoric acid solution (I) metered at the same time adding a basic aqueous alkali hydroxide solution in order to keep the pH of the resulting reaction mixture in the range of 5 to 8. Too low a pH of the template solution (II) or of the resulting reaction mixture at a pH of 5 has the disadvantage that, in addition to the desired crystal phase according to the invention, it is also possible to form further crystal phases, eg. As metal hydrogen or Metalldihydrogenphosphate. An excessively high pH of the template solution (II) above a pH of 8 has the disadvantage that traces of metal hydroxides can form which represent undesired contamination in the products according to the invention. The basic aqueous alkali metal hydroxide solution is preferably added in such a way that a pH in the range from 6 to 7 is established in the reaction mixture when the solution (I) is metered in. This has the advantage that only the crystal phase according to the invention forms.

After precipitation of the phosphate according to the invention this is separated from the reaction solution. This is also done again by methods known per se, for example filtration, centrifugation, sedimentation etc. The phosphate separated off from the reaction solution is then expediently dried, ie. H. dewatered. The drying can be carried out either under ambient atmosphere, under a protective gas atmosphere and / or under reduced pressure and / or elevated temperature (above room temperature, 25 ° C). The methods suitable for this purpose are familiar to the person skilled in the art and require no further description. In addition, reference is made to the following examples. During drying, free water is removed from the residue separated from the reaction solution. Depending on the desired product but also bound water of crystallization is removed by drying up to a desired hydrate level of the product.

In a preferred embodiment of the invention, the precipitated phosphate separated from the reaction solution is up to a hydrate stage Mn ₃ (P0 ₄ ) ₂ ^■ a H ₂ 0 or (Mn _x Met _y ) ₃ (P0 ₄ ) 2 ^■ a H ₂ 0 with 0 <a <9, particularly preferably with a 0, 3 or 7, very particularly preferably with a = 3, dried. The hydrate stage with a = 3 has the novel structure type according to the invention. It is stable over a wide temperature range. The hydrate stages with a = 0 and a = 7 are sufficiently stable. In a preferred embodiment, the manganese (Mn) -containing phosphate produced by the process according to the invention is a mixed-metal phosphate which contains at least one other metal (Met) in addition to manganese (Mn), the phosphate preferably containing not more than 7 different metals. In most cases it will be convenient to produce a mixed metal phosphate of the type according to the invention with two, three or four different metals. It is often desirable to prepare a mixed-metal phosphate which, in addition to manganese (Mn), contains one or two metals selected from Fe, Co and Ni in high proportions as so-called main metals and / or one or more metals in small proportions as so-called doping metals , For example, it may be advantageous for a manganese containing as main metal according to the invention containing a small proportion of a further metal, for example Mg, Al, Cu or a Lanthanoidenmetalls, as demonstrated in the following examples. With particular preference, the manganese (Mn) -containing mixed-metal phosphate contains at least 40 at.% Mn, preferably at least 60 at.% Mn, more preferably at least 80 at.% Mn, most preferably at least 90 ath. -% Mn.

In an alternative preferred embodiment, the manganese (Mn) -containing phosphate produced by the process according to the invention is a monometallic phosphate which, in addition to process-related impurities, contains only manganese (Mn) as the metal. The process according to the invention has considerable advantages over the state of the art in terms of efficiency, process costs, energy consumption and product purity achievable, in particular in the production of mixed-metal phosphates. In addition, the proportions of the various metals in the mixed metal phosphate can be adjusted very easily and accurately. Furthermore, the process according to the invention makes it possible to control certain material parameters, such as crystal phase and cation distribution, morphology, crystallite and secondary particle size and the chemical purity of the products obtained, by suitably selecting the precipitation conditions, such as pH, concentrations, temperature, etc. , This is in the known methods in which metal phosphates and other metal salts mixed and then thermally reacted by calcination, not or only to a limited extent possible and is usually associated with a much higher energy consumption.

The manganese (Mn) -containing phosphate produced according to the invention particularly preferably has the novel "Mn ₃ (PO ₄ ) ₂ ^.3 H ₂ O structure type" described herein with peaks in the powder X-ray diffraction diagram at 10.96 ± 0.05, 12, 78 ± 0.17, 14.96 ± 0.13, 17.34 ± 0.15, 18.98 ± 0.18, 21, 75 ± 0.21, 22.07 ± 0.11, 22.97 ± 0.10, 25.93 ± 0.25, 26.95 ± 0.30, 27.56 ± 0.10, 29.19 ± 0.12, 29.84 ± 0.21, 30.27 ± 0, 12, 34.86 ± 0.21, 35.00 ± 0.20, 35.33 ± 0.30, 35.58 ± 0.10, 35.73 ± 0.12, 42.79 ± 0.45, 43.37 ± 0.45, 44.70 ± 0.15 and 44.93 ± 0.20 degrees two-theta based on CuKa radiation. This manganese (Mn) -containing phosphate of the novel structural type preferably has an orthorhombic unit cell with lattice parameters of 13.2 ± 0.2, 8.6 ± 0.2, and 8.1 ± 0.2 angstroms.

In a preferred embodiment of the process according to the invention, the precipitation of the manganese (Mn) -containing phosphate in step e) is carried out at a temperature in the range from 5 to 105.degree. C., preferably in the range from 10 to 40.degree. The temperature can be kept constant by a suitable control unit in the range +/- 5 ° C to the desired point. Higher temperatures generally result in a more pronounced crystallinity of the products. Temperatures below 5 ° C are possible, but require unnecessary cooling. The best solution is to carry out the precipitation at room temperature or at the reaction-dependent temperature. to lead. At temperatures above 105 ° C, the reaction mixture boils, which is undesirable and may be disadvantageous. Particularly preferably, the precipitation of the phosphate in step e) is carried out at a temperature in the range from 10 to 40 ° C., since this is the most cost-effective. In a further preferred embodiment of the method according to the invention is dispersed in the aqueous solution (I) prior to metering to the template solution (II) in step d) a carbon source, wherein the carbon source comprises elemental carbon or consists exclusively of elemental carbon and is preferably selected from Graphite, expanded graphite, carbon black or black carbon, carbon nanotubes (CNT), fullerenes, graphene, vitreous carbon, carbon fibers, activated carbon or mixtures thereof, or the aforesaid carbon source comprises organic compounds in addition to elemental carbon wherein the organic compounds are preferably selected from hydrocarbons, alcohols, aldehydes, carboxylic acids, surfactants, oligomers, polymers, carbohydrates or mixtures thereof.

The addition of a carbon source to the aqueous solution (I) in the process according to the invention allows the production of phosphate-carbon composites, whereby an electrically conductive equipment of the material itself and / or the products can be made of the material possible, for example for the production of cathode materials for lithium ion batteries. Due to the added amount and type of carbon source directly to the solution (I), the resulting carbon content and thus the conductivity can be freely adjusted within certain limits. Conveniently, the carbon source of the aqueous solution (I) in an amount of 1 to 10 wt .-% carbon, preferably 1, 5 to 5 wt .-% carbon, more preferably 1, 8 to 4 wt .-% carbon, based on the weight of the phosphate precipitated together with the carbon, too. Too high a carbon content has the disadvantage of reducing the maximum possible amount of cathode active material in later use in lithium ion batteries. At a carbon content below 1 wt .-%, a sufficient conductivity increase is no longer achieved.

To increase the dispersion stability of the carbon component in the solution, it may be advantageous, depending on the type of carbon source, to finely distribute the carbon source by the action of mechanical forces in the solution. In addition to known methods for introducing high shear forces, the use of agitator ball mills is particularly suitable for this purpose. By using a stirred ball mill, in addition to the fine distribution of the carbon source, its average particle size or agglomerate size can also be modified. For example, the mean grain size of a graphite can be reduced to <300 nm. The dispersions obtained are very stable and have little tendency to sedimentation of the graphite solid even after several days, although this generally has initially hydrophobic material properties. The described treatment and an excess of free phosphate or phosphoric acid in the mixture modify the surfaces of the graphite and stabilize the solid in the dispersion. There are also known methods for the hydrophilization of carbon or graphite, which are used advantageously can be, for example, the partial oxidation of the surface. Furthermore, the stability of the dispersion of the carbon source in the solution (I) can be improved with advantage by the addition of surface-active substances. The solution may be added in addition to other carbon sources or, alternatively, a polymer or biopolymer as carbon source. Advantages here provide soluble carbon sources under the acidic conditions prevailing in the solution (I). If the component is insoluble, the distribution in the solution can also be improved by the action of shear forces.

In a further preferred embodiment of the process according to the invention, the aqueous medium containing phosphoric acid for the preparation of the aqueous solution (I) contains the phosphoric acid in a molar excess in relation to the sum of the molar amounts of the metal cations of the oxidic metal compounds to be introduced into the solution the metals to be introduced in elemental form or as an alloy. Without an excess of phosphoric acid, the redox process does not proceed or at such a slow rate that the process may not be of interest to commercial application.

Conveniently, the concentration of phosphoric acid in the aqueous solution (I) in stage a) is 5% to 85%, preferably 10% to 40%, more preferably 15% to 30%, most preferably 20% to 25% on the weight of the aqueous solution (I).

In a further preferred embodiment of the method according to the invention, the template solution (II) contains the phosphate ions, calculated as P ₂ O ₅ , in a concentration in the range from 0.35 to 1.85 mol / L. A concentration of phosphation below 0.35 mol / LP ₂ 0 ₅ has the disadvantage that it would unnecessarily dilute the reaction mixture and, in the case of a commercial application, would have to treat an unnecessarily large volume of filtrate. A phosphate concentration above 1.85 mol / LP ₂ 0 ₅ has the disadvantage that the reaction mixture can not be optimally mixed due to a high solids content and the resulting high viscosity. This can lead to local concentration gradients, which in turn can adversely affect the formation of the desired crystal phase.

In a further preferred embodiment of the process according to the invention, the reaction of the oxidic metal compounds with the elemental forms or alloys of the metals in stage a) is carried out at a temperature in the range from 5 ° C. to 105 ° C., preferably in the range from 10 ° C. to 75 ° ° C, more preferably in the range of 20 ° C to 50 ° C, by. At temperatures within the range according to the invention, the reaction with various metal components can be carried out smoothly and at a satisfactory speed, without the occurrence of oxidation phenomena with atmospheric oxygen. Furthermore, it is advantageous to carry out the reaction of the oxidic metal compounds with the elemental forms or alloys of the metals in step a) with thorough mixing in order to achieve a uniform reaction and to avoid local excess concentrations within the reaction solution. This also applies to the subsequent precipitation stage.

It is expedient to carry out the reaction of the oxidic metal compounds with the elemental forms or alloys of the metals in stage a) for a period of from 1 minute to 240 minutes, preferably from 5 minutes to 120 minutes, more preferably from 30 minutes to 90 minutes. The reaction time required for a sufficiently complete reaction depends on the reactants and the reaction conditions and can be easily determined by the skilled person by a few simple experiments. If the reaction time is too short, the reaction will generally not be sufficiently complete and will yield too much unreacted starting materials. The reaction time should also not be too long, since the process is then less economical. A complete reaction is desired to obtain a defined metal composition. As described above, the concentration of individual metals in the solution can optionally be adjusted by the addition of suitable metal salts. However, this means additional expense and increases the cost of the process and the risk of intolerable Anionenkontamination.

The invention also includes a manganese (Mn) containing mono-metal phosphate of the type Mn ₃ (P0 ₄₎ ₂ ^■ 3 H ₂ 0 or mixed metal phosphate of the type (Mn _x Met _y) ₃ (P0 ₄₎ 2 ^■ 3 H ₂ 0, where x + y = 1 and Met represents one or more metals selected from Fe, Co, Ni, Sc, Ti, V, Cr, Cu, Zn, Be, Mg, Ca, Sr, Ba, Al, Zr, Hf, Re , Ru, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, wherein the phosphate in the powder X-ray diffraction pattern shows peaks at 10.96 ± 0.05, 12.78 ± 0, 17, 14.96 ± 0, 13, 17.34 ± 0.15, 18.98 ± 0.18, 21, 75 ± 0.21, 22, 07 ± 0, 1 1, 22.97 ± 0 , 10, 25,93 ± 0,25, 26,95 ± 0,30, 27,56 ± 0, 10, 29, 19 ± 0, 12, 29,84 ± 0,21, 30,27 ± 0, 12 , 34.86 ± 0.21, 35.00 ± 0.20, 35.33 ± 0.30, 35.58 ± 0.10, 35.73 ± 0.12, 42.79 ± 0.45, 43 , 37 ± 0.45, 44.70 ± 0.15 and 44.93 ± 0.20 degrees two-theta based on CuKo radiation, preparable or prepared by the method of the invention described herein. The invention also encompasses the use of the phosphate according to the invention for the production of lithiated (Li-containing) cathode material for Li-ion accumulators, for example according to methods described in the literature. The use of the phosphate according to the invention as a precursor for the preparation of lithiated cathode material has the advantage over the use of the methods known for this purpose that in the phosphate according to the invention the various desired metal cations are already present in an ideally isotropically distributed form in a high-purity precursor which its crystal phase, composition and morphology can be clearly characterized by simple and well-known methods. The inventively preferred nanoscale platelet shape of the primary crystallites ensures the lowest possible diffusion distances and diffusion times in lithiation via simple and inexpensive calcination. The already ideal isotropic distribution of the metal ions also reduces the necessary calcination and calcination times, since no Matallionendiffusion across grain boundaries across is necessary. The defined crystal structure ensures clear and reproducible reaction paths during calcination and in the production of cathode materials. The effort in the precise production of Präkursormischungen is significantly reduced compared to known methods, since the essential components are already present in a defined compound. The high purity of the phosphate according to the invention, in particular the most extensive absence or very low levels of anionic impurities such as sulfates, nitrates, chlorides, etc., in a later battery application by a significantly higher cycle life and durability, which increases the efficiency of lithium-ion batteries and applications eg in electric vehicles.

The invention further comprises a lithiated (Li-containing) cathode material for Li-ion accumulators, prepared using manganese (Mn) -containing phosphate according to the invention.

The invention further comprises a Li-ion accumulator which contains the lithiated (Li-containing) cathode material according to the invention.

Description of the figures

Figure 1: X-ray powder diffraction pattern of the product from Example 4 with CuK _a radiation;

Figure 2: Transmission electron micrograph (TEM) of individual platelet-shaped

Crystals of the product of Example 4;

FIG. 3: electron diffraction images from TEM investigations of individual platelet dyes

Crystals of the product of Example 4;

Figure 4: Electron micrograph of the product of Example 1;

Figure 5: Electron micrograph of the product of Example 3;

FIG. 6: Electron micrograph of the product from Example 18; Figure 7: X-ray powder diffraction pattern of the product of Example 17 with CuK _a radiation, fully indexed by PDF 75-1186 (Fe ₃ (P0 ₄₎ ₂ 8 x H ₂ 0) and 41-0375 (Co ₃ (P0 ₄₎ ₂ x 8 H ₂ O); Figure 8: X-ray powder diffraction pattern of the product of Example 16 with CuK _a radiation, fully indexed by PDF 75-1186 (Fe ₃ (P0 ₄₎ ₂ 8 x H ₂ 0) (or 46-1388 (Ni ₃ P0 ₄₎ ₂ x 8H ₂ 0);

Figure 9: Powder X-ray diffraction pattern of the product from Example 3 with CuK _a radiation.

Examples Example 1

A phosphoric acid solution (I) was prepared from 80 g of 75% H ₃ PO ₄ and 160 g of deionized water. Into this solution (I) was added 14.3 g of Mn ₃ O ₄ and 3.5 g of Fe. The solution (I) was stirred for 90 minutes at room temperature and then filtered to remove any remaining residue from the solution.

Furthermore, a basic solution of 40g NaOH and 1000g deionized water was prepared. Subsequently, 25 g of H ₃ PO _{4 were} charged with 100 g of water in a reaction vessel and neutralized with the basic solution to a pH of 7 to obtain the template solution (II). To the neutralized template solution (II), the Me ²⁺ phosphoric acid solution (I) and the basic solution were simultaneously metered in with stirring so that the pH of the template solution (II) was always kept between 6.5 and 7. After completion of the addition, the solution was stirred for a further 5 minutes. The precipitated solid was then filtered with suction using a Nutsche filter and washed with deionized water. The filter cake was dried at 120 ° C in a convection oven.

Example 2

A phosphoric acid solution (I) was prepared from 230 g of 75% H ₃ PO 4 and 460 g of deionized water. In this solution (I) were 8.9 g MnO 2 and 30,1g Mn ₃ 0 ₄ and 13, 1 g of Fe. The solution (I) was stirred for 60 minutes at room temperature and then filtered to remove any remaining residue from the solution.

Furthermore, a basic solution of 120g NaOH and 3000g deionized water was prepared. Subsequently, 25 g of H ₃ PO _{4 were} charged with 100 g of water in a reaction vessel and neutralized with the basic solution to a pH of 7 to obtain the original solution (II). To the neutralized template solution (II), the Me ²⁺ phosphoric acid solution (I) and the basic solution were simultaneously metered in with stirring so that the pH of the template solution (II) was always kept between 6.5 and 7. After completion of the addition, the solution was stirred for a further 5 minutes. The precipitated solid was then removed with the aid of a Suction filter filtered off and washed with deionized water. The filter cake was dried at 90 ° C in a convection oven.

Example 3

A phosphoric acid solution (I) was prepared from 80 g of 75% H ₃ PO ₄ and 160 g of deionized water. Into this solution (I), 14.3 g of Mn ₃ O ₄ and 3.8 g of Co were added. The solution (I) was stirred for 60 minutes at 60 ° C and then filtered to remove any remaining residue from the solution. Furthermore, a basic solution of 40.4 g NaOH and 229 g water was prepared. Subsequently, 25 g of H ₃ PO _{4 were} charged with 100 g of water in a reaction vessel and neutralized with the basic solution to a pH of 7 to obtain the template solution (II). To the neutralized template solution (II), the Me ²⁺ phosphoric acid solution (I) and the basic solution were simultaneously metered in with stirring so that the pH of the template solution (II) was always kept between 6.5 and 7. After completion of the addition, the solution was stirred for a further 5 minutes. The precipitated solid was then filtered with suction using a Nutsche filter and washed with deionized water. The filter cake was dried at 70 ° C in a convection oven.

Example 4

A phosphoric acid solution (I) was prepared from 80 g of 75% H ₃ PO ₄ and 160 g of deionized water. Into this solution (I) was added 14.1 g of Mn ₃ O ₄ and 4.5 g of Mn. The solution (I) was stirred for 90 minutes at 20 ° C and then filtered to remove any remaining residue from the solution. Furthermore, a basic solution of 17.6 g of NaOH and 158.7 g of water was prepared. Subsequently, 10 g of H ₃ PO _{4 were} charged with 100 g of water in a reaction vessel and neutralized with the basic solution to a pH of 7 to obtain the template solution (II). To the neutralized template solution (II), 100 g of the Me ²⁺ phosphoric acid solution (I) and the basic solution were simultaneously metered in with stirring so that the pH of the template solution (II) was always kept between 6.5 and 7. After completion of the addition, the solution was stirred for a further 5 minutes. The precipitated solid was then filtered with suction using a Nutsche filter and washed with deionized water. The filter cake was dried at 80 ° C in a convection oven. Example 5

A phosphoric acid solution (I) was prepared from 80 g of 75% H ₃ PO ₄ and 160 g of deionized water. Into this solution (I) was added 14.3 g of Mn ₃ O ₄ and 3.5 g of Fe. The solution (I) was stirred for 90 minutes at room temperature and then 17.7 g of CoSO ₄ -6H ₂ 0 dissolved in 20 g of water was added. Subsequently, the resulting solution was filtered to remove any remaining residue. Furthermore, a basic solution of 40g NaOH and 1000g water was prepared. Subsequently, 25 g of H ₃ PO _{4 were} charged with 100 g of water in a reaction vessel and neutralized with the basic solution to a pH of 7 to obtain the template solution (II). To the neutralized template solution (II), the Me ²⁺ phosphoric acid solution (I) and the basic solution were simultaneously metered in with stirring so that the pH of the template solution (II) was always kept between 6.5 and 7. After completion of the addition, the solution was stirred for a further 5 minutes. The precipitated solid was then filtered with suction using a Nutsche filter and washed with deionized water. The filter cake was dried at 80 ° C in a convection oven.

Example 6

A phosphoric acid solution (I) was prepared from 80 g of 75% H ₃ PO ₄ and 160 g of deionized water. Into this solution (I) was added 14.3 g of Mn ₃ O ₄ and 3.5 g of Fe. The solution (I) was stirred for 90 minutes at 60 ° C and then added 2.6g Mg (acetate) ₂ -6H ₂ 0 dissolved in 20g of water. Subsequently, the resulting solution was filtered to remove any remaining residue.

Furthermore, a basic solution of 50g NaOH and 450g water was prepared. Subsequently, 10 g of H ₃ PO _{4 were} charged with 100 g of water in a reaction vessel and neutralized with the basic solution to a pH of 7 to obtain the template solution (II). To the neutralized template solution (II), the Me ²⁺ phosphoric acid solution (I) and the basic solution were simultaneously metered in with stirring so that the pH of the template solution (II) was always kept between 6.5 and 7. After completion of the addition, the solution was stirred for a further 5 minutes. The precipitated solid was then filtered with suction using a Nutsche filter and washed with deionized water. The filter cake was dried at 80 ° C in a convection oven.

Example 7

A phosphoric acid solution (I) was prepared from 80 g of 75% H ₃ PO ₄ and 160 g of deionized water. Into this solution (I), 14.3 g of Mn ₃ O ₄ and 2.2 g of Fe and 1.5 g of Co were added. The solution (I) was stirred for 90 minutes at room temperature and then filtered to remove any remaining residue from the solution.

Furthermore, a basic solution of 40g NaOH and 1000g deionized water was prepared. Subsequently, 25 g of H ₃ PO _{4 were} charged with 100 g of water in a reaction vessel and neutralized with the basic solution to a pH of 7 to obtain the template solution (II). To the neutralized template solution (II), the Me ²⁺ phosphoric acid solution (I) and the basic solution were simultaneously metered in with stirring so that the pH of the template solution (II) was always kept between 6.5 and 7. After completion of the addition, the solution was stirred for a further 5 minutes. The precipitated solid was then sucked with the aid of a Nutsche filter and with washed deionized water. The filter cake was divided and one part each dried at 60 ° C or 120 ° C in a convection oven.

Example 8

A phosphoric acid solution (I) was prepared from 80 g of 75% H ₃ PO ₄ and 160 g of deionized water. Into this solution (I), 14.3 g of Mn ₃ O ₄ and 2.2 g of Fe and 1.5 g of Co were added. The solution (I) was stirred for 90 minutes at room temperature and then filtered to remove any remaining residue from the solution. To this solution then added with 2.6 g of Mg (acetate) -6H ₂ 0 dissolved in 20 g of water.

Furthermore, a basic solution of 40g NaOH and 1000g deionized water was prepared. Subsequently, 25 g of H ₃ PO _{4 were} charged with 100 g of water in a reaction vessel and neutralized with the basic solution to a pH of 7 to obtain the template solution (II). To the neutralized template solution (II), the Me ²⁺ phosphoric acid solution (I) and the basic solution were simultaneously metered in with stirring so that the pH of the template solution (II) was always kept between 6.5 and 7. After completion of the addition, the solution was stirred for a further 5 minutes. The precipitated solid was then filtered with suction using a Nutsche filter and washed with deionized water. The filter cake was divided and one part each dried at 60 ° C or 120 ° C in a convection oven.

Example 9

A phosphoric acid solution (I) was prepared from 1090 g of 75% H ₃ PO ₄ and 2380 g of deionized water. Into this solution (I) was added 209 g of Mn ₃ O ₄ and 51 g of Fe. The solution (I) was stirred for 90 minutes at room temperature and then to 100 g of this solution 1, 94g Al ₂ (S0 ₄ ) ₃ -18H ₂ 0 dissolved in 20 ml of water was added to the solution and filtered to any remaining residue from the solution to remove.

Example 10

A phosphoric acid solution (I) was prepared from 1090 g of 75% H ₃ PO ₄ and 2380 g of deionized water. Into this solution (I) was added 209 g of Mn ₃ O ₄ and 51 g of Fe. The solution (I) was stirred at room temperature for 90 minutes and then 0.65 g of Cu were added to 100 g of this solution. CO ₃ Cu (OH) ₂ 0.5H ₂ O dissolved in 20 ml dilute HCl added to the solution and filtered to remove any remaining residues from the solution.

Furthermore, a basic solution of 50g NaOH and 450g water was prepared. Subsequently, 10 g of H ₃ PO _{4 were} charged with 100 g of water in a reaction vessel and neutralized with the basic solution to a pH of 7 to obtain the template solution (II). To the neutralized template solution (II), the Me ²⁺ phosphoric acid solution (I) and the basic solution were simultaneously metered in with stirring so that the pH of the template solution (II) was always kept between 6.5 and 7. After completion of the addition, the solution was stirred for a further 5 minutes. The precipitated solid was then sucked off with the aid of a suction filter and washed with deionized water. The filter cake was dried at 80 ° C in a convection oven.

Example 11

A phosphoric acid solution (I) was prepared from 1090 g of 75% H ₃ PO ₄ and 2380 g of deionized water. Into this solution (I) was added 209 g of Mn ₃ O ₄ and 51 g of Fe. The solution (I) was stirred for 90 minutes at room temperature and then to 100 g of this solution 1.10 g LaCI ₃ -7H ₂ 0 dissolved in 20 ml of water was added to the solution and filtered to remove any remaining residues from the solution. Furthermore, a basic solution of 50g NaOH and 450g water was prepared. Subsequently, 10 g of H ₃ PO _{4 were} charged with 100 g of water in a reaction vessel and neutralized with the basic solution to a pH of 7 to obtain the template solution (II). To the neutralized template solution (II), the Me ²⁺ phosphoric acid solution (I) and the basic solution were simultaneously metered in with stirring so that the pH of the template solution (II) was always kept between 6.5 and 7. After completion of the addition, the solution was stirred for a further 5 minutes. The precipitated solid was then filtered with suction using a Nutsche filter and washed with deionized water. The filter cake was dried at 80 ° C in a convection oven.

Example 12

A phosphoric acid solution (I) was prepared from 1090 g of 75% H ₃ PO ₄ and 2380 g of deionized water. Into this solution (I) was added 209 g of Mn ₃ O ₄ and 51 g of Fe. The solution (I) was stirred for 90 minutes at room temperature and then to 100 g of this solution 1, 12g EuCl ₃ -7H ₂ 0 dissolved in 20ml of water was added to the solution and filtered to remove any remaining residue from the solution.

Furthermore, a basic solution of 50g NaOH and 450g water was prepared. Subsequently, 10 g of H ₃ PO _{4 were} charged with 100 g of water in a reaction vessel and neutralized with the basic solution to a pH of 7 to obtain the template solution (II). To the neutralized template solution (II), the Me ²⁺ phosphoric acid solution (I) and the basic solution were simultaneously metered in with stirring so that the pH of the template solution (II) was always kept between 6.5 and 7 has been. After completion of the addition, the solution was stirred for a further 5 minutes. The precipitated solid was then filtered with suction using a Nutsche filter and washed with deionized water. The filter cake was dried at 80 ° C in a convection oven. Example 13

A phosphoric acid solution (I) was prepared from 1090 g of 75% H ₃ PO ₄ and 2380 g of deionized water. Into this solution (I) was added 209 g of Mn ₃ O ₄ and 51 g of Fe. The solution (I) was stirred for 90 minutes at room temperature, and then this solution, 0.66 g of SnCl ₂ -2H ₂ 0 were dissolved in 20ml of dilute HCl added to the solution and filtered to remove any remaining residue from the solution to 100 g.

Example 14

A phosphoric acid solution (I) was prepared from 1090 g of 75% H ₃ PO ₄ and 2380 g of deionized water. Into this solution (I) was added 209 g of Mn ₃ O ₄ and 51 g of Fe. The solution (I) was stirred for 90 minutes at room temperature and then 0.95 g of ZrOCl ₂ dissolved in 20 ml of dilute HCl was added to the solution to 100 g of this solution and filtered to remove any remaining residue from the solution.

Example 15

A phosphoric acid solution (I) was prepared from 1090 g of 75% H ₃ PO ₄ and 2380 g of deionized water. Into this solution (I) was added 209 g of Mn ₃ O ₄ and 51 g of Fe. The solution (I) was stirred at room temperature for 90 minutes, and then to 100 g of this solution was added 0.33 g of CaCl ₂ dissolved in 20 ml of dilute HCl added to the solution and filtered to remove any remaining residues from the solution.

Example 16 (comparison)

A phosphoric acid solution (I) was prepared from 80 g of 75% H ₃ PO ₄ and 160 g of deionized water. Into this solution (I) was added 14.1 g of Fe ₃ O ₄ and 3.5 g of Fe. The solution (I) was stirred at 60 ° C. for 60 minutes and then 33.1 g of NiSO ₄ -6H ₂ O dissolved in 100 g of water were added. The resulting solution was filtered to remove any remaining residue.

Furthermore, a basic solution of 50g NaOH and 500g water was prepared. Subsequently, 10 g of H ₃ PO _{4 were} charged with 100 g of water in a reaction vessel and neutralized with the basic solution to a pH of 7 to obtain the template solution (II). To the neutralized template solution (II), the Me ²⁺ phosphoric acid solution (I) and the basic solution were simultaneously metered in with stirring so that the pH of the template solution (II) was always kept between 6.5 and 7. After completion of the addition, the solution was stirred for a further 5 minutes. The precipitated solid was then sucked off with the aid of a suction filter and washed with deionized water. The filter cake was dried at 100 ° C in a convection oven.

Example 17 (comparison)

A phosphoric acid solution (I) was prepared from 80 g of 75% H ₃ PO ₄ and 160 g of deionized water. Into this solution (I) was added 14.1 g of Fe ₃ O ₄ and 3.8 g of Co. The solution (I) was stirred for 60 minutes at 60 ° C and then filtered to remove any remaining residue from the solution.

Furthermore, a basic solution of 50g NaOH and 500g water was prepared. Subsequently, 10 g of H ₃ PO _{4 were} charged with 100 g of water in a reaction vessel and neutralized with the basic solution to a pH of 7 to obtain the template solution (II). To the neutralized template solution (II), the Me ²⁺ phosphoric acid solution (I) and the basic solution were simultaneously metered in with stirring so that the pH of the template solution (II) was always kept between 6.5 and 7. After completion of the addition, the solution was stirred for a further 5 minutes. The favored The solid was then sucked off with the aid of a suction filter and washed with deionized water. The filter cake was dried at 70 ° C in a convection oven.

Example 18 (comparison)

A phosphoric acid solution (I) was prepared from 80 g of 75% H ₃ PO ₄ and 160 g of deionized water. Into this solution (I) was added 14.4 g of Co ₃ O ₄ and 3.8 g of Co. The solution (I) was stirred for 60 minutes at room temperature and then filtered to remove any remaining residue from the solution. Furthermore, a basic solution of 41.9 g of NaOH and 376.8 g of water was prepared. Subsequently, 10 g of H ₃ PO _{4 were introduced} with 100 g of water in a reaction vessel and neutralized with the basic solution to a pH of 7 to obtain the template solution (II). To the neutralized template solution (II), the Me ²⁺ phosphoric acid solution (I) and the basic solution were simultaneously metered in with stirring so that the pH of the template solution (II) was always kept between 6.5 and 7. After completion of the addition, the solution was stirred for a further 5 minutes. The precipitated solid was then filtered with suction using a Nutsche filter and washed with deionized water. The filter cake was dried at 80 ° C in a convection oven. Example 19 (comparison)

A phosphoric acid solution (I) was prepared from 80 g of 75% H ₃ PO ₄ and 160 g of deionized water. Into this solution (I) was added 14.1 g of Fe ₃ O ₄ and 3.5 g of Fe. The solution (I) was stirred for 60 minutes at 60 ° C and then filtered to remove any remaining residue from the solution.

Furthermore, a basic solution of 17.6 g of NaOH and 158.7 g of water was prepared. Subsequently, 10 g of H ₃ PO _{4 were} charged with 100 g of water in a reaction vessel and neutralized with the basic solution to a pH of 7 to obtain the template solution (II). 100 g of the Me ²⁺ phosphoric acid solution (I) and the basic solution were added simultaneously to the neutralized original solution (II) with stirring so that the pH of the original solution (II) was always between 6.5 and 7 has been. After completion of the addition, the solution was stirred for a further 5 minutes. The precipitated solid was then filtered with suction using a Nutsche filter and washed with deionized water. The filter cake was dried at 80 ° C in a convection oven.

Example 20 (comparison)

A phosphoric acid solution (I) was prepared from 80 g of 75% H ₃ PO ₄ and 160 g of deionized water. Into this solution (I) was added 14.4 g of Co ₃ O ₄ and 3.5 g of Fe. The solution (I) was stirred for 60 minutes at room temperature and then filtered to remove any remaining residue from the solution. Furthermore, a basic solution of 41.9 g of NaOH and 376.8 g of water was prepared. Subsequently, 10 g of H ₃ PO _{4 were} charged with 100 g of water in a reaction vessel and neutralized with the basic solution to a pH of 7 to obtain the template solution (II). To the neutralized original solution (II), the Me ²⁺ phosphoric acid solution (I) and the basic solution were simultaneously metered in with stirring so that the pH of the template solution (II) was always kept between 6.5 and 7. After completion of the addition, the solution was stirred for a further 5 minutes. The precipitated solid was then filtered with suction using a Nutsche filter and washed with deionized water. The filter cake was dried at 80 ° C. in a circulating air drying cabinet.

Table 1 summarizes Examples 1 to 20 and the results of the analytical tests of the respective products. Examples 1 to 15 show that according to the inventive process in which manganese (Mn) containing monometallic and mixed metal phosphates "Mn ₃ (P0 ₄₎ ₂ ^■ 3 H ₂ 0-structure type" from be obtained. The ratio of metal to phosphate (P0 ₄ ) in the products obtained is about 3 to 2. The metals manganese (Mn) and, if present, the metals Fe, Ni and Co are present in the products in their divalent form. It is conceivable that very small amounts of these metals are present in a different oxidation state, for example, Fe can oxidize to the particle surfaces to a small extent, for. B when drying and high temperatures. Such slight deviations from the divalent form are to be considered in the sense of the present invention as unavoidable impurities, whereby the scope of protection of the invention is not abandoned. The doping metals may be present in the form of their stable or known oxidation states.

Examples (comparative examples) 16 to 20 show that monom etal or mixed metal phosphates are obtained by the comparable method but without the addition of elemental manganese (Mn) or manganese-containing oxidic compounds which do not contain the "Mn ₃ (P0 ₄ ) ₂ ^■ 3 H ₂ 0 structure type ". In the X-ray diffraction analysis, the products of Examples 16 to 20 could all be assigned to the vivanite crystal structure type [Fe ₃ (PO ₄ ) ₂ 8 H ₂ O] or its dehydration stages.

The drying temperature had an influence on the content of bound water of crystallization. The higher the drying temperature and the longer the drying time, the lower the content of water of crystallization. A reduced water partial pressure accelerated the drying.

The products according to the invention of Examples 1 to 15 all show the same analytical X-ray diffraction pattern in the powder X-ray diffraction diagram with Pea ks be i 10, 96 ± 0.05, 12.78 ± 0.17, 14.96 ± 0.13, 17.34 ± 0.15, 18.98 ± 0.18, 21, 75 ± 0.21, 22.07 ± 0, 1 1, 22.97 ± 0.10, 25.93 ± 0.25, 26 , 95 ± 0.30, 27.56 ± 0.10, 29, 19 ± 0.12, 29.84 ± 0.21, 30.27 ± 0.12, 34.86 ± 0.21, 35.00 ± 0.20, 35.33 ± 0.30, 35.58 ± 0.10, 35.73 ± 0.12, 42.79 ± 0.45, 43.37 ± 0.45, 44.70 ± 0.15 and 44, 93 ± 0.20 degrees two-theta, based on CuKa radiation. Only the peak positions, depending on the nature and concentration of the various metals in the multimetallic phosphates to slight shifts, which are caused by different ionic radii and varying occupancy rate of the cation sites in the crystal lattice of the unit cell.

The powder X-ray analysis and electron diffraction analyzes in the transmission electron microscope prove for the products of Examples 1 to 15 an orthorhom bische unit cell with axial lengths of 13.2 +/- 0.2; 8.6 +/- 0.2 and 8.1 +/- 0.2 Angstroms.

The powder X-ray diffraction diagrams obtained for the products according to the invention with the abovementioned peaks and the product cells intended for the products with the said parameters and slightly varying within the given ranges depending on the composition of the metal components are for compounds of composition Mn ₃ (P0 ₄ ) ₂ ^' 3H ₂ 0 and their (pseudo) binary, (pseudo) ternary or (pseudo) quaternary variants in the relevant databases are not yet known. For the products according to the invention, a new "Mn ₃ (PO ₄ ) ₂ ^.3H ₂ O structure type" was identified. The structure is observed when the product according to the invention exclusively contains Mn as metal (see Example 3), but also when other metals are present. For a connection of the type Mn ₃ (P0 ₄ ) ₂ 3H ₂ 0, there is a PDF entry (Powder Diffraction File) in the database of the ICDD (International Center for Diffraction Data) under the number 003-0426, but there are between them deposited data and for the inventive products of the "Mn ₃ (P0 ₄ ) ₂ ^■ 3 H ₂ 0-structure type" experimentally determined here values no match regarding position, number and intensity of the described reflexes. For the compound described in the ICDD database, no crystallographic data are additionally stored which describe the crystal structure in more detail. The products of the invention specified by the herein "Mn ₃ (P0 ₄₎ ₂ ^■ 3 H ₂ 0-structure type" have thus far not been described.

The products according to the invention predominantly have a platelet-shaped morphology of the primary crystallites, it being possible to determine the platelet thickness in the order of about 10 to 50 nm in the scanning electron microscope.

The platelet-shaped morphology of the products according to the invention allows, in principle, a dense packing of the crystallites, i. the platelets can stack at a lower cut-off volume than is the case with round spherical particles. Layered aggregates or agglomerates of this material can be easily converted by conventional methods under the action of shear forces in dispersions of the primary particles.

The small thickness of the crystal platelets of the product according to the invention ensures a high reaction rate in the lithiation of the phosphates to active cathode materials, since the Lithium ions in the implementation of only short diffusion paths must cover. This also leads to a better performance of the finished cathode material, since the diffusion distances and times of Li ions can be significantly reduced compared to a conventional material.

Table 1

T * = drying temperature; "vac" = vacuum

- M 1, M2, M3 and M4 under "analytical results" = wt .-% of the introduced metal, based on the total amount of the introduced metals (- = for equal metals proportion of the metal already given in the previous column)

Claims

claims

Mn (Mn) -containing monometallic phosphate of the Mn ₃ (P0 ₄ ) ₂ ^· 3 H ₂ 0 or mixed metal phosphate type (Mn _x Met _y ) ₃ (PO ₄ ) 2 ^· 3 H ₂ O, where x + y = 1 and Met represents one or more metals selected from Fe, Co, Ni, Sc, Ti, V, Cr, Cu, Zn, Be, Mg, Ca, Sr, Ba, Al, Zr, Hf, Re, Ru, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, characterized in that the phosphate in the powder X-ray diffraction pattern peaks at 10.96 ± 0.05, 12.78 ± 0, 17, 14.96 ± 0.13, 17.34 ± 0.15, 18.98 ± 0.18, 21.75 ± 0.21, 22.07 ± 0.11, 22.97 ± 0.10, 25.93 ± 0.25, 26.95 ± 0.30, 27.56 ± 0.10, 29.19 ± 0.12, 29.84 ± 0.21, 30.27 ± 0.12, 34, 86 ± 0.21, 35.00 ± 0.20, 35.33 ± 0.30, 35.58 ± 0.10, 35.73 ± 0.12, 42.79 ± 0.45, 43.37 ± 0.45, 44.70 ± 0.15 and 44.93 ± 0.20 degrees two-theta based on CuKo radiation.

Manganese (Mn) -containing phosphate according to claim 1, characterized in that it has a Orthorhom bische unit cell with lattice parameters of 13.2 ± 0.2, 8.6 ± 0.2 and 8.1 ± 0.2 Angstrom.

Manganese (Mn) -containing phosphate according to one of the preceding claims, characterized in that it is present as carbon composite and 1 to 10 wt .-% carbon, preferably 1.5 to 5 wt .-% carbon, more preferably 1.8 to 4 Wt .-% carbon, based on the total weight of phosphate and carbon.

Manganese (Mn) -containing phosphate according to one of the preceding claims, characterized in that it has a platelet-shaped morphology, preferably with a platelet thickness (= smallest spatial extent) in the range of 10 to 100 nm, preferably in the range of 20 to 70 nm, particularly preferably in the range of 30 to 50 nm.

Manganese (Mn) containing phosphate according to any one of the preceding claims, characterized in that it is a mixed metal phosphate of the type (Mn _x Met _y) ₃ (P0 ₄₎ 2 ^■ 3 H ₂ 0 and the ratio of Mn: (Mn + Met ) = x: (x + y)> 0.15, preferably> 0.4, more preferably> 0.5.

Manganese (Mn) -containing phosphate according to one of Claims 1 to 5, preparable or prepared according to one of Claims 7 to 19 [Adjust according to the reduction in the number of claims!].

A method for preparing a manganese (Mn) containing monometallic phosphate type Mn ₃ (P0 ₄₎ ₂ ^■ a H ₂ 0 or mixed-metal phosphate of the type (Mn _x Met _y) ₃ (P0 ₄₎ ₂ ^■ a H ₂ 0, where x + y = 1, a = 0 to 9, and Met represents one or more metals selected from Fe, Co, Ni, Sc, Ti, V, Cr, Cu, Zn, Be, Mg, Ca, Sr, Ba, Al, Zr , Hf, Re, Ru, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, the process being characterized in that

a) preparing an aqueous solution (I) which contains at least divalent manganese cations (Mn ²⁺ ) and optionally one or more of the metals Fe, Co and / or Ni as divalent cations, by oxidic metal (II) -, metal (III) - and / or metal (IV) compounds or mixtures thereof or compounds having mixed oxidation states, selected from hydroxides, oxides, oxide hydroxides, oxide hydrates, carbonates and hydroxide carbonates, of at least one of the metals Mn, Fe, Co and / or Ni together with the elemental forms or alloys of at least one of the metals Mn, Fe, Co and / or Ni in an aqueous medium containing phosphoric acid and the oxidic metal compounds with the elemental forms or alloys of the metals (in a redox reaction) to reacting the divalent metal ions, wherein at least one of the oxidic metal compounds and / or at least one of the elemental forms or alloys of metal comprises manganese,

b) optionally separated solids from the phosphoric acid aqueous solution (I),

(c) if the phosphate is a mixed-metallic phosphate and, in addition to the metals introduced into the solution in step (a), further metals selected to be Met, the aqueous solution (I) further comprises at least one compound of at least one of the Met metals in the form of an aqueous solution Solution or as a solid in the form of a salt, wherein the at least one compound is preferably selected from hydroxides, oxides, oxide hydroxides, oxide hydrates, carbonates, hydroxide carbonates, carboxylates, sulfates, chlorides or nitrates of the metals, d) one from an aqueous phosphoric acid solution Neutralization prepared with an aqueous alkali hydroxide solution or a prepared from an aqueous solution of one or more alkali metal phosphates template solution (II) having a pH of 5 to 8 provides,

e) adding the aqueous solution (I) to the initial solution (II) and at the same time adding a basic aqueous alkali metal hydroxide solution in such a way that the pH of the resulting reaction mixture is kept in the range from 5 to 8, preferably 6 to 7, the phosphate of the type Mn ₃ (P0 ₄ ) ₂ ^■ a H ₂ 0 or (Mn _x Met _y ) ₃ (P0 ₄ ) 2 ^■ a H ₂ O is precipitated,

f) separating the precipitated phosphate from the reaction solution.

A method according to claim 7, characterized in that drying the precipitated and separated from the reaction solution phosphate, preferably up to a Hydratstufe Mn ₃ (P0 ₄₎ ₂ ^■ a H ₂ 0 or (Mn _x Met _y) ₃ (P0 ₄₎ ₂ ^■ a H ₂ 0 with 0 <a <9, particularly preferably with a = 0, 3 or 7, very particularly preferably with a = 3. Method according to one of claims 7 or 8, characterized in that the manganese (Mn) -containing phosphate is a mixed metallic phosphate which contains at least one other metal (Met) in addition to manganese (Mn), the phosphate preferably not more than 7 different metals contains.

Method according to one of claims 7 to 9, characterized in that the manganese (Mn) -containing phosphate based on all metals contained at least 40 at .-% Mn, preferably at least 60 at .-% Mn, more preferably at least 80 at .-% Mn, very particularly preferably contains at least 90 at.% M n or contains the manganese (Mn) -containing phosphate in addition to process-related impurities as metal only manganese (Mn).

Method according to one of claims 7 to 10, characterized in that the manganese (Mn) -containing phosphate in the powder X-ray diffraction pattern peaks at 10.96 ± 0.05,

12.78 ± 0, 1 7, 1 4, 96 ± 0, 13, 17,34 ± 0, 15, 18,98 ± 0, 18, 21, 75 ± 0,21, 22,07 ± 0, 1 1, 22 , 97 ± 0.10, 25.93 ± 0.25, 26.95 ± 0.30, 27.56 ± 0.10, 29, 19 ± 0.12, 29.84 ± 0.21, 30.27 ± 0, 1 2, 34, 86 ± 0.21, 35.00 ± 0.20, 35.33 ± 0.30, 35.58 ± 0.10, 35.73 ± 0.12,

42.79 ± 0.45, 43.37 ± 0.45, 44.70 ± 0.15 and 44.93 ± 0.20 degrees two-theta based on CuKo radiation

Process according to one of Claims 7 to 11, characterized in that the manganese (Mn) -containing phosphate is an orthorhombic unit cell with lattice parameters of 13.2 ± 0.2, 8.6 ± 0.2 and 8.1 ± 0.2 Angstrom has.

Process according to one of claims 7 to 12, characterized in that the phosphate containing the precipitation of the manganese (Mn) in stage e) is carried out at a temperature in the range from 5 to 105 ° C, preferably in the range from 10 to 40 ° C ,

Method according to one of claims 7 to 13, characterized in that dispersed in the aqueous solution (I) before the addition to the template solution (II) in step e) a carbon source, wherein the carbon source comprises elemental carbon or consists exclusively of elemental carbon and is preferably selected from graphite, expanded graphite, carbon blacks or carbon blacks, carbon nanotubes (CNTs), fullerenes, graphene, vitreous carbon, carbon fibers, activated carbon or mixtures thereof, or the aforementioned carbon source comprises organic compounds besides elemental carbon , wherein the organic compounds are preferably selected from hydrocarbons, alcohols, aldehydes, carboxylic acids, surfactants, oligomers, polymers, carbohydrates or mixtures thereof.

A method according to claim 14, characterized in that the carbon source in the aqueous solution (I) in an amount of 1 to 10 wt .-% carbon, preferably 1, 5 to 5 Wt .-% carbon, more preferably from 1, 8 to 4 wt .-% carbon, based on the weight of the co-precipitated with the carbon mixed metallic phosphate added. 16. The method according to any one of claims 7 to 15, characterized in that the phosphoric acid-containing aqueous medium for the preparation of the aqueous solution (I), the phosphoric acid in a molar excess over the sum of the molar amounts of the metal cations to be introduced into the solution of the oxidic metal compounds and the metals to be introduced in elemental form or as an alloy.

17. The method according to any one of claims 7 to 16, characterized in that the template solution (II) contains the phosphate ions, calculated as P ₂ 0 ₅ , in a concentration in the range of 0.35 to 1, 85 mol / L. 18. The method according to any one of claims 7 to 17, characterized in that reacting the oxidic metal compounds with the elemental forms or alloys of the metals in step a) at a temperature in the range of 5 ° C to 105 ° C, preferably in the range from 10 ° C to 75 ° C, more preferably in the range of 20 ° C to 50 ° C, and / or with intensive mixing and / or for a period of 1 min to 240 min, preferably from 5 min to 120 min , more preferably from 30 minutes to 90 minutes.

19. The method according to any one of claims 7 to 18, characterized in that the concentration of phosphoric acid in the aqueous solution (I) in step a) 5% to 85%, preferably 10% to 40%, particularly preferably 15% to 30% , very particularly preferably 20% to 25%, based on the weight of the aqueous solution (I).

20. Use of a manganese (Mn) -containing phosphate according to any one of claims 1 to 6 to r H first l l u ng of L ith i ming (Li containing em) cathode material for Li-ion accumulators.

21. A lithium ion-containing (Li-containing) cathode material for Li-ion secondary batteries prepared by using a manganese (Mn) -containing phosphate according to any one of claims 1 to 6.