EP3847711A1

EP3847711A1 - Method of producing a rechargeable high-energy battery having an anionically redox-active composite cathode

Info

Publication number: EP3847711A1
Application number: EP19765458.5A
Authority: EP
Inventors: Ulrich Wietelmann
Original assignee: Albemarle Germany GmbH
Current assignee: Albemarle Germany GmbH
Priority date: 2018-09-05
Filing date: 2019-09-05
Publication date: 2021-07-14
Also published as: WO2020049104A1; CN112789749A; KR20210049095A; US12062785B2; JP2021535551A; JP7420790B2; US20210320296A1

Abstract

The invention relates to a method of producing a rechargeable high-energy battery having an anionically redox-active composite cathode containing lithium hydroxide as electrochemically active constituent in a form in which it has been mixed and contacted with electronically or mixedly conductive transition metals and/or transition metal oxides, so as to form an electronically or mixedly conductive network, this mixture is applied to an output conductor, and the composite cathode formed in this way is introduced into a cell housing together with a separator, a Li-conductive electrolyte and a lithium-containing anode, so as to give an electrochemical cell, and this is subjected to at least one first forming cycle.

Description

Process for producing a rechargeable high-energy battery with an anion-redox-active composite cathode

The invention relates to a method for producing a rechargeable battery

High energy battery with an anion-redox active composite cathode.

State of the art

The principle of operation of commercial rechargeable lithium-ion batteries is based on an insertion mechanism: both the negative electrode (anode) and the positive electrode (cathode) consist of materials that can insert lithium ions without fundamental changes in the microstructure. While a carbon-based material - graphite or hard carbon - is used as the anode material, the cathode active materials consist of transition metal oxides. The transition metals in the latter oxides are redox-active, i.e. they change their oxidation state when loading or unloading. This is demonstrated by the following example reaction:

LiM ^{+ l, l} 0 ₂ Li ⁺ + e- + M ^{+ IV} 0 ₂ M = discharge metal, e.g. Ni, Co, Mn

With the cathode materials currently in use, the oxidation level of the redox-active metal centers is only changed by one level when charging / discharging the battery, in the above case the oxidation levels change between +111 and +

IV instead. For this reason, the capacity of the cathode materials is relatively low.

In the case of the classic cathode material L1C0O2, the theoretical capacity is 274 mAh / g, of which only approx. 135 mAh / g can be used in practice. The graphitic material used for the anode also has a relatively low capacity for the limit stoichiometry LiC6 with 372 mAh / g. As a result, the theoretical energy density for the graphite (C6) / LiCo0 _{2 system is also} unsatisfactorily low and is around 380 Wh / g. Another disadvantage of lithium ion batteries lies in the fact that the cathode materials mainly used are those of the unavailable elements such as cobalt and nickel. There is a fear that the metals mentioned are insufficient Amount is available to ensure a nationwide supply of lithium batteries for worldwide electromobility and stationary energy storage.

Open battery systems are being investigated as an alternative to cation redox active positive electrode materials. These contain a porous structure, usually made of carbon, which is open to the environment and the surface of which is covered with a noble metal-containing catalyst, so that diffused oxygen can be bound to form lithium oxides (oxygen reduction reaction):

In the initially formed product - lithium superoxide (L1O2) - the oxygen has an average oxidation number of -0.5. Further absorption of lithium produces lithium peroxide (L12O2) with an oxygen oxidation number of -1. The latter lithium oxide can be converted back into lithium and elemental oxygen in the presence of a metal catalyst catalyzing the oxygen oxidation, in reverse of the formation reaction:

It is disadvantageous that the air electrode described above has only a very moderate power density and, above all, only a very limited reversibility, so that this cathode shape is still a long way from being used in practical batteries. In addition, there is a large distance of typically 0.5 - 1 V between the charging and discharging potential, so that the energy efficiency ("round trip efficiency") is completely unsatisfactory. The current major technical challenges lead to the expectation that the lithium / air battery can be commercialized at the earliest in 10 - 20 years. For an overview, see K. Amine et al., Chem. Review 2014, 561 1 -40, 1 14.

There are also efforts to use lithium oxides (L12O, L12O2 and L1O2) as active cathode materials that work according to the anion redox principle. Since all of the lithium oxygen compounds mentioned are electronic insulators, they must be in finely divided (amorphous or nanoparticulate) form or in a very thin layer and the individual particles must be contacted using a conductive network. In addition, there are, for example, conductive, finely divided metals as well as many metal oxides and lithium metal oxides. Such systems are known from the literature and only exemplary embodiments are mentioned here. So a composite cathode consisting of 20% L12O2, 20% carbon black and 60% PEO-LiCI0 ₄ could be discharged / charged three times in an electrochemical cell with lithium foil as counter electrode (MD Wardinsky and DN Bennion, Proc. Electrochem. Soc. 1993, 93-23 (Proc. Symp. New Sealed Rech. Batt. And Supercapacitors, 1993, 389-400)).

Lithium peroxide (L12O2) can be contacted by cover grinding with mixed-conductive LiNio _{, 33} Coo _{, 33} Mno _{, 33} 0 ₂ and completely decomposed cathodically (Y. Bie et al., Chem. Commun. 2017, 53, 8324-7). Composites consisting of a mixture of Co-Metall and L12O, both in nanoparticulate form, can also be completely decomposed cathodically (Y. Sun, Nature Energy, January 2016, 15008). The practical functionality of a full battery cell containing nanoparticulate lithium oxides (a mixture of U2O, L12O2 and L1O2), embedded in a matrix of Co ₃ 0 ₄ , is known (Z. Zhu, Nature Energy, 25 July 2016, 161 1 1). To avoid oxygen release from the lithium oxides, a charging voltage of about 3 - 3.5 V vs Li / Li ^{+ must} not be exceeded.

However, the use of lithium oxides as cathode active materials has practical disadvantages in terms of commercialization. Lithium superoxide (L1O2) is not thermodynamically stable in crystalline form, but breaks down into L12O2 and oxygen (K.C. Lau, J. Phys. Chem. C 1 15, 23625-33). Lithium peroxide is a strong oxidizing agent and decomposes in contact with water with the evolution of oxygen. Both connections mentioned can therefore not be handled safely on a larger scale. Lithium oxide L12O, although thermodynamically stable, is not commercially available. It is very caustic and can only be achieved using energy-intensive processes, e.g. gain the thermal decomposition of L12CO3 at temperatures from around 1000 ° C (RB Poeppel in: Advances in ceramics, Vol. 25, "Fabrication and properties of lithium ceramics", ed. IJ Hastings and GW Hollenberg, 1989, 1 1 1 -1 16).

Task

The invention has for its object to provide a method for manufacturing and an electrochemical storage system that ensure a high enough energy density of at least 500 Wh / kg especially for mobile applications can. Furthermore, commercially available and safe to handle active materials with the lowest possible content of rare or poorly available metals are to be used.

Solution of the task

The object is achieved by a method for producing a rechargeable high-energy battery with an anion-redox-active composite cathode, in which the anion-redox-active composite cathode contains lithium hydroxide as an electrochemically active component, which is mixed and contacted with electronically or mixed conductive transition metals and / or transition metal oxides lies, so that an electronic or mixed-conductive network is formed, this mixture is applied to a current conductor and the composite cathode formed in this way is introduced into a cell housing together with a separator, a lithium-conductive electrolyte and a lithium-containing anode, so that a electrochemical cell is present. This is subjected to at least one initial forming cycle. In the case of a rechargeable high-energy battery whose positive electrode (cathode) consists of a composite material which, as an electrochemically active component, lithium compounds selected from at least lithium hydroxide (LiOH), and optionally lithium oxide (L1 ₂ O), lithium peroxide (L12O2) and / or lithium superoxide (L1O2), the cathode contains lithium hydride (LiH) at least after the first discharge cycle (ie in the lithium-rich state). This LiH arises according to one of the equations (1) to (3), see below. The electrochemically active constituents are embedded in an electronically or mixedly conductive network which contains transition metal particles and / or electronically conductive transition metal oxides and, if appropriate, further conductivity-improving materials.

For the production of the electrochemically active composite cathode material, at least the lithium oxygen compound lithium hydroxide (LiOH) and optionally a further lithium oxygen compound selected from L1 ₂ O, L1 ₂ O ₂ and L1O ₂ are used. Lithium hydroxide is commercially available and is easy and safe to use. The proportion of LiOH in the composite cathode material, based on the total content of the above-mentioned lithium oxygen compounds, is at least 10 mol%, preferably at least 30 mol%. The negative electrode (anode) contains at least one lithium-donating component or compound with an electrochemical potential of <2 V against the Li / Li ⁺ reference electrode. The lithium-donating, electrochemically active component or compound is selected from metallic lithium, a lithium-containing metal alloy, a lithium nitrido transition metalate or composite materials, the electrochemically active component of which is a metal nitrogen compound, which is embedded in a transition metal-containing electronic or mixed-conductive network.

When producing a rechargeable high-energy battery, preferably a secondary lithium battery, containing a composite cathode according to the invention and an anode, the active materials of which have an electrochemical potential of <2 V against Li / Li ⁺ , the two electrodes must be properly balanced (i.e. weight-matched) with regard to the electrochemically active ingredients they contain. Proper balancing is characterized by the fact that the electrochemical active materials can be used as completely as possible. In the present case, this means in particular that the anode contains a molar amount of electrochemically activatable lithium, i.e. electrochemically extractable from the anode, before the first discharge cycle, which contains at least half, preferably at least the same and particularly preferably at least twice the molar amount of the corresponds to the LiOH content of the composite cathode. This is explained below.

When using LiOH in the cathode of a rechargeable lithium battery, lithium hydride (LiH) is formed in addition to lithium oxide (L12O), lithium peroxide (L12O2) and / or lithium superoxide (L1O2) in the first discharge cycle. The general cathode half-reactions when the galvanic cells according to the invention are first discharged correspond to at least one of the following three equations:

As a result of the first discharge reaction, in addition to lithium hydride, at least one lithium oxide compound is formed which is anion-redox active and which does so for the subsequent cycles represents electrochemically active cathode material used. The inventors have found that reactions (1) to (3) surprisingly only take place if adequate electronic or mixed electronic / ionic contacting of the lithium hydroxide particles is ensured. In addition, the lithium hydroxide particles should preferably be in finely divided form (nanoparticulate). The same also applies to any other lithium oxygen compounds present in the cathode material, selected from L12O, L12O2 and LiC> 2.

Since L12O has the highest lithium content of the considered lithium oxygen compounds and thus a cathode with the highest theoretical electrochemical capacity can be formed, reaction equation (1) with a molar ratio of 1: 2 between LiOH: extractable (i.e. electrochemically active) lithium, particularly preferred.

The electrochemically active cathode material according to the invention in the lithium-rich form present after the first discharge cycle can in principle also be produced by mixing L12O and / or another lithium oxygen compound and LiH. However, this manufacturing variant is not particularly advantageous for practical reasons. Lithium hydride is namely not stable to reactive Luftbe components such as water vapor and carbon dioxide (decomposition to lithium hydroxide or lithium carbonate). In addition, lithium oxide is not commercially available and requires energy-intensive manufacturing processes.

In the subsequent charge-discharge cycles, further, sometimes irreversible, changes in the electrode composition take place. In contrast to the prior art (Z. Zhu, Nature Energy, July 25, 2016, 161 1 1), the cathode according to the invention contains lithium hydride at least after it has been discharged for the first time (ie in the lithium-rich state). Surprisingly, the lithium hydride formed in the first discharge cycle decomposes smoothly in the subsequent charge cycle, presumably according to the following reaction:

In addition to hydrogen gas, lithium is released. Rechargeable lithium batteries require operation to prevent access to metallic lithium reactive gases and compounds. For example, the air components oxygen, nitrogen, carbon dioxide, water vapor and other air trace components are reactive towards lithium. As a result, rechargeable lithium batteries generally have to be operated in the closed state (ie filled in a hermetically sealed housing). In the present case, hydrogen gas is formed at least in the first charging cycle. The hydrogen formed is not reactive towards metallic lithium at moderate temperatures, but it would lead to an undesirable build-up of pressure within a hermetically sealed battery cell. In order to avoid this undesirable effect, at least the first and possibly further discharge / charge cycles must be carried out in the open state. Such a procedure during the first cycle or the first cycles, the so-called forming cycles, is a known method. In order to avoid excessive contact of the battery constituents with the environment, the pressure equalization is generally carried out via an open capillary, which is closed after the gas-forming reaction or the gas-forming reactions have ended completely.

The lithium formed in the first charging cycle migrates in a cationic form through the separator to the anode and separates there in the metallic state or reacts with substances or compounds present there which are capable of absorbing lithium. This can be an at least partially reversible reaction, such as, for example, with a graphitic material, a metal capable of absorbing lithium, a low-metal alloy, and low-lithium forms of lithium nitride transition metalates and / or composite materials, the electrochemically active component of which is a metal nitrogen compound, the metal nitrogen compound being a transition metal-containing compound electronic or mixed-conductive network is embedded. However, irreversible reactions such as, for example, electrolyte decomposition and / or the formation of a passivating layer on the surface of particulate or sheet-like constituents of the anode, in particular their electrochemically active components, can also be involved. The irreversibly consumed lithium in this way indirectly increases the gravimetric capacity of a rechargeable lithium battery cell, since otherwise lithium from another source, for example a lithium oxygen compound selected from L1 ₂ O, U ₂ O ₂ , L1O ₂ and / or one other cathode material, such as a lithium transition metal oxide, must be used. In the case of lithium hydride, the hydrogen gas which does not react with the remaining cell components, in particular the electrolyte, which is produced during the release of lithium escapes from the battery cell, while in the case of the lithium oxygen compounds mentioned, oxygen gas reactive with the electrolyte is produced. If the lithium used for the passivation or protective layer formation comes from a lithium transition metal oxide introduced in the cathode, the delithiated material, i.e. ίί _cd MOg (5 = 0 to x; x and y can assume values between 1 and 10) or completely lithium-free transition metal oxide back. Due to the lack of lithium, this can no longer participate in the battery redox process; it is therefore an electrochemically inactive mass that lowers the energy density of the system. In this case, the lithium hydride formed according to the invention acts as an elegant prelithiation agent.

The half reactions in the cathode that occur during the cyclization of a rechargeable electrochemical cell are schematically as follows:

These are (5) to (7) read from left to right to discharge reactions. The double arrows are intended to symbolize that it is reversible (provided sufficient electronic or mixed contacting is required).

The electrochemically active lithium compounds selected from lithium hydroxide (LiOH), lithium oxide (L12O), lithium peroxide (L12O2) and / or lithium superoxide (L1O2) and possibly lithium hydride (LiH) must be embedded in an electronically or mixed conductive network consisting of finely divided transition metal particles and / or finely divided conductive transition metal oxide compounds with an electrochemical potential (lithium intercalation potential) of> 2 V against Li / Li ⁺ . It is important that the closest possible contact between the electrochemically active lithium compounds and the transition metal or the conductive transition metal oxide compounds with an electrochemical potential> 2 V is guaranteed. It is also advantageous if the latter as well as the electronically or mixed-conductive transition metal oxide compounds with an electrochemical potential of> 2 V against Li / Li ^{+ are present} in the finest possible distribution, ie amorphous or nanoparticulate form. The exact dimensions of the preferred nanoparticulate impression depend on the mechanical form factor (ie the three-dimensional shape of the particles). In the case of spherical (or similar) particle shapes, this is 0.1-100 nm, preferably 1-30 nm.

The solid components of the cathode composite material can be comminuted by a grinding process, preferably using a high-energy mill, and brought into close contact with one another. When using a planetary ball mill, nanoparticulate forms of the lithium oxygen compounds and the electronically or mixedly conductive transition metals or transition metal oxide compounds with an electrochemical potential of> 2 V against Li / Li ⁺ are obtained in this way. Nanoparticulate particle morphologies can also be produced by alternative physical (vapor deposition, plasma and laser methods) or chemical processes, for example solvent-based processes, preferably sol / gel processes.

The molar ratio between the finely divided transition metals and / or the electronically or mixed-conductive transition metal oxide compounds on the one hand and the active materials based on lithium oxygen compounds selected from LiOH, L12O, L12O2 and L1O2 on the other hand in the cathode is in the range of 1: 100 to 1: 1, preferably 1:50 to 1: 1.5.

The transition metal M is preferably the elements from the 3rd to 12th group of the Periodic Table of the Elements, particularly preferably M = Sc, Ti, Zr, Hf, V, Cr, Mo, W, Mn, Fe, Ni, Co, Cu, Ag , Zn and the rare earth metals La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, TM, Yb and Lu or any mixture of the above-mentioned transition metals.

Electronically conductive transition metal oxides with M = a metal from the 3rd to 12th group of the Periodic Table of the Elements are used as transition metal oxide compounds. Both binary (MO _x ) and ternary (MM ' _y O _x ) and higher mixed phases can be used, the further metal M' at least is a further transition metal from the 3rd to 12th group of the periodic table and / or the element lithium (Li _y MO _x ). Here are: w, y = 0 to 8; x = 0.5 to 4.

The following metal oxide compounds are preferably used: binary metal oxides such as titanium oxides (TiO, T12O3), vanadium oxides (V2O3, VO, VO2), iron oxides (Fe ₃ 0 ₄ , FeO), cobalt oxides (C0O2, Co ₃ 0 ₄ ), nickel oxides (N12O3 ), Manganese oxides (Mn02, Mn ₃ 0 ₄ ), chromium oxides (Cr02, Cr ₃ 03), niobium oxides (NbO); layer-structured lithium metal oxides (L1C0O2, LiNiC> 2, Li (Ni, Mn, Co) C> 2), L1V3O8; Spinel-structured lithium metal oxides (LiMn20 ₄ , LiMnNi02, LiNio.5Mn1 5O4,, L1V3O5; inverse spinel-structured lithium metal oxides (UN1VO4, LiCoV0 ₄ ); olivine-structured lithium metal oxides (LiFeP0 ₄ , L1VPO ₄ ). The chemical formulas given above give the ideal chemical formulas of the basic compounds. In practice, however, these are used in a slightly or more modified form, which means materials with structure-stabilizing doping (eg Al-stabilized lithium cobalt oxide, "NCA") or compounds made with foreign metals or non-metals doped for the purpose of increasing the conductivity Doping modified variants of the parent compounds can also be used according to the invention.

It is particularly preferred to use electronically or mixed-conductive transition metal oxides and lithium transition metal oxides, which can reversibly release and insert lithium. In these cases, the additional electrochemical capacity of these conductivity improvers can be used if their electrochemical potential has approximately the same potential position as the electrochemically active lithium oxygen compounds (approx. 3 V). The electronic conductivity of the metal oxide compounds which can be used according to the invention at room temperature is at least 10 ⁷ S / cm, preferably at least 10 ⁶ S / cm and particularly preferably at least 10 ⁵ S / cm.

The rechargeable high-energy battery according to the invention has a negative electrode (anode) which contains a material with an electrochemical potential <2 V against Li / Li ⁺ . These can be: graphitic materials (graphite itself, hard carbon, graphene and the like); metallic lithium; elements capable of alloying with lithium (for example aluminum, silicon, germanium, tin, lead, boron, zinc, mixtures thereof) and lithium-containing compounds of the metallic elements mentioned; Transition metal nitrides (nitridometalates) (MM ' _V N _X ) with M = a metal from the 3rd to 12th group of the Periodic Table of the Elements and M' = at least one further transition metal from the 3rd to 12th group of the Periodic Table and / or the ele ment lithium (Li _y MN _x ) and with y = 0 to 8; x = 0.5 to 1; Metal nitrogen compounds of the general formulas

LiM ² _z (NH) o, 5x ₊ z (I) and

Li _m M ² _n (NH ₂ ) i _{+ n} (II), where

(I) and (II) can be present in any mixing ratio and M ² = an alkaline earth element (Mg, Ca, Sr, Ba or any mixture thereof) and

x = 0-4; z = 0-2

m = 1 or 0; n = 1 or 0, where (m + n) = 1.

In the fully charged (lithium-rich) state, the metal nitrogen compounds correspond to the general formulas (III) and / or (IV)

Li2z ₊ xM ² z (NH) o, 5x ₊ z (III)

Li ₃ N n (LiM ² N) (4-2m) LiH (IV) where

(III) and (IV) can be in any mixing ratio and

M ² = alkaline earth element (Mg, Ca, Sr, Ba or any mixture thereof) x = 0 - 4; z = 0-2

m = 1 or 0; n = 1 or 0, where (m + n) = 1.

Metal nitrogen compounds are preferably used as electrochemically active anode materials, the metal nitrogen compounds being embedded in a transition-metal-containing electronic or mixed-conductive network. In the fully discharged (low-lithium) state of charge, the electrochemically active metal nitrogen compound has a composition which is indicated by at least one of the two general formulas (I) and / or (II). The transition metal-containing electronic or mixed-conductive network contains finely divided transition metals M in elemental form or finely divided conductive interstitial transition metal compounds with an electrochemical potential (lithium intercalation potential) of <2.5 V against Li / Li ⁺ . The transition metal powder M is preferably the elements of the 3rd to 12th group of the Periodic Table of the Elements, particularly preferably M = Sc, Ti, Zr, Hf, V, Cr, Mo, W, Mn, Fe, Co, Ni, Cu, Ag , Zn and the rare earth metals La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Tm, Yb and Lu or any mixture of the transition metals mentioned.

Electronically conductive interstitial compounds are used as transition metal compounds with an electrochemical potential (lithium intercalation potential) of <2.5 V against Li / Li ⁺ . These are preferably transition metal nitrides (nitridometalates) and / or transition metal carbides, each with M = a metal from the 3rd to 12th group of the Periodic Table of the Elements and / or transition metal tallides with M = a metal from the 3rd to 10th Group of the periodic table of the elements. Both binary (MN _X , MC _X, MH _X ) and ternary (MM ' _y N _x ; MM'yC _x ; MM' _y H _x ) and higher mixed phases can be used, the further metal M 'being at least one further transition metal from the 3rd to 12th group of the periodic table (M _x M ' _y N _z ) and / or the element is lithium (Li _y MN _x ; Li _y MC _x ; LiwM _x M' _y N _z ; Li _w M _x M'yH _z ; etc). Here are: w, y = 0 to 8; x = 0.5 to 1; z = 0 to 3.

In the discharged (low-lithium) state according to the generic formula (I), the nitridometalates preferably consist of at least one of the following compounds: Li ₂ NH, MgNH, CaNH, Li ₂ Mg (NH) _2, Li ₂ Ca (NH) _2, MgCa ( NH) _2, Li ₄ Mg (NH) _3, Li ₂ Mg ₂ (NH) 3 and / or according to the generic formula (II) from one or more of the following compounds: LiNH ₂ , Mg (NH ₂ ) ₂ , Ca ( NH ₂ ) ₂ .

If the high-energy battery according to the invention is charged by applying an external voltage, the active N-containing anode materials change into a lithium-rich state. When fully charged, the lithium-rich compounds are formed according to the generic formulas (III), preferably: Li ₄ NH, Li ₂ MgNH, Li ₂ CaNH, Li ₆ Mg (NH) _2, Li ₆ Ca (NH) ₂ , Li ₄ MgCa (NH ) _2, Lii ₀ Mg (NH) _3, Li ₈ Mg ₂ (NH) ₃ and / or according to the generic formula (IV), preferably: Li ₃ N, MgLiN, CaLiN and LiH.

The transition metal compounds listed above with the qualitative composition Li _w M _x M'yE _z (E = N, C, H; w, y = 0 to 8; x = 0.5 to 1; z = 0 to 3) belong to the group the so-called interstitial metal compounds or Alloys, ie the embedded foreign elements E, that is: carbon, nitrogen or hydrogen, are arranged on interstitial layers (interstitial sites) of the underlying metal lattice. The stoichiometries given indicate the highest or highest levels (limit stoichiometries) of carbon, nitrogen or hydrogen. However, the interstitial compounds are not exactly stoichiometric compounds, that is to say all compositions, starting from the pure metal to the limit stoichiometry, are generally possible and mostly stable. All compounds with lower foreign element contents, i.e. qualitatively represented by Li _w M _x M ' _y E _z-6 (5 can have any value between 0 and z), are also electronic or mixed-conducting materials and are therefore suitable for the division of the nitrogen-containing composite anode materials .

The electronically conductive transition metals or their corresponding likewise electronically conductive nitride, carbide or hydride compounds are preferably used in finely divided form (nanoparticulate). They can be mixed as homogeneously as possible with the anode material, which also contains nanoparticulate lithium nitrogen, using a physical mixing process, with subsequent pressing (in technical manufacturing processes generally by calendering) in the anode strip production ensuring good contacting of the individual particles and the fully functional nitrogen and transition metal containing composite anode material is obtained. Suitable composite anode materials can also be produced by chemical processes, for example reactions with nitrogen sources. Elemental nitrogen (N ₂ ) serves as the preferred nitrogen source; Ammonia (NH3); Hydrazine (N ₂ H ₄ ); Urea (CH ₄ N ₂ 0). In the case of ammonolysis with NH3, the metals, that is to say lithium and the selected transition metals, are reacted with ammonia, preferably at elevated temperatures and under pressure conditions. The amide compounds obtained can then be converted further by subsequent thermolysis, for example into imide compounds and / or nitrides. If non-nitridic conductivity improvers are desired, appropriate transition metal hydrides and / or transition metal carbides can be added before or after ammonolysis. After removing excess ammonia, the remaining solids can be ground together. This measure causes a particle size reduction and an improvement in the contact. When reacting with nitrogen at mostly elevated temperatures and pressures, nitridic phases form immediately. In this case, too, desired non-non-iridic conductivity improvers can be added.

In a preferred embodiment of the invention, the lithium nitrogen-containing anode materials are co-ground with the conductivity-improving transition metals or their nitrides, carbides or hydrides. A high-energy mill, for example of the planetary ball mill type, is used for the grinding.

Further materials which improve the functionality of the anode can be added to the nitrogen-containing composite anode materials. These primarily include non-metal-based conductivity improvers, lithium-donating additives and binders. All conductive forms of elemental carbon (graphite, carbon black, graphene, carbon nanotubes) come into consideration as non-metal-based conductivity improvers. Lithium-metal additives (preferably coated, ie surface passivated and in powder form or as a thin film) or lithium-rich compounds such as lithium graphite (LiC6-5, d = 0-5) or coated lithium silicides (Li _n SiO _x @Li ₂ 0) can be used as lithium-donating additives come. The organic polymers conventionally used for the production of electrodes can be used as binders. These include PTFE, PVdF, polyisobutylene (eg: Oppanols ^® from BASF) and similar materials. In the composite anode material containing nitrogen and transition metal, the weight ratio between the finely divided transition metal or the electronically or mixed conductive transition metal compound Li _w M _x M'yE _z (E = N, C, H; w, y = 0 to 8; x = 0.5 to 1; z = 0 to 3) on the one hand and the nitrogen-containing electrochemically active nitrogen-containing anode material on the other hand generally between 1: 100 to 1: 2. It is preferably between 1:50 to 1: 5 The ready-to-use (complete) nitrogen and transition metal-containing composite anode can also contain further conductivity improvers (up to 30% by weight), binders (up to 20% by weight) and / or prelithiating agents (up to 20% by weight).

Anodes containing metallic lithium are also preferably used, where the lithium is present either as a sheet metal or powder electrode or as an alloy with a metal selected from silicon, tin, boron and aluminum.

As electrolytes for the rechargeable high-energy battery according to the invention with an anion-redox-active composite cathode, the composite cathode, which is in the State before the first discharge in an electronically or mixed-conductive network embedded lithium hydroxide and, if necessary, additionally contains one or more lithium oxygen compounds selected from L12O, L12O2 and L1O2, come the types familiar to the person skilled in the art (liquid, gel, polymer and Solid electrolytes) in question. In the matrix used, soluble lithium salts with weakly coordinating, oxidation-stable anions are used as the conductive salt for liquid, polymer and gel-polymer systems. These include, for example, LiPF ₆ , lithium fluoroalkylphosphates, LiBF ₄ , imide salts (e.g. LiN (S0 ₂ CF3) 2), UOSO2CF3, methide salts (e.g. LiC (S0 ₂ CF ₃ ) 3), LiCI0 ₄ , lithium chelatoborates (e.g. LiB (C20 ₄ ) 2 , also called "LiBOB"), lithium fluorochelatoborates (e.g. LiC ₂ 0 ₄ BF ₂ , called "LiDFOB"), lithium chelatophosphates (e.g. LiP (C ₂ 0 ₄ ) ₃ , called "LiTOP") and

Lithium fluorochelatophosphates (e.g. Li (C ₂ 0 ₄ ) ₂ PF ₂ ). Salts with anions which are stable against anion dissociation and which are fluorine-free are particularly preferred.

Solid electrolytes, ie Li-ion-conducting glasses, ceramics or crystalline inorganic solids are also particularly preferred. Examples of such materials are: lithium thiophosphates (e.g. Li ₃ PS ₄ ), argyrodite (L16PS5X with X = CI, Br, I), phosphidosilicates (e.g. Ü2SiP2), nitridophosphates (e.g. Li _2.9 P0 _3.3 No, 36), nitridoborophosphates (e.g. Li ₄₇ B3Pi ₄ N ₄₂ ), metal sulfidophosphates (e.g. LiioGeP2Sn), garnets (e.g. Ü ₇ La ₃ Zr ₂ 0i ₂ ), titanium phosphates (Li 1 _{, d} AIo _{, d} Tϊ i _, s (P0 ₄ ) ₃ ) and

Borohydride compounds (e.g. LiBH ₄ , and L12B12H12).

The anode compartment is separated from the cathode compartment by means of a lithium ion-permeable but electronically insulating separator (e.g. consisting of microporous polyolefins) or a solid electrolyte (of the type of an inorganic solid or a solid polymer material).

The invention is illustrated by the following examples:

EXAMPLE 1 Production of a Composite Cathode Containing Lithium Hydroxide by Milling (Transition Metal Oxide and Carbon Black as Conductivity Improver)

In an Ar-filled glove box, 0.9 g of Co ₃ 0 ₄ (<50 nm, supplier Aldrich), 3.6 g of anhydrous lithium hydroxide powder (supplier Albemarle Germany) and 0.2 g of carbon black (AB 400) were premixed in a beaker. The homogenized mixture was mixed with approx. 27 g 3 mm zircon ceramic balls in a 50 mL zircon ceramic Grinding bowl filled and closed. The mixture was then milled in a planetary ball mill (Pulverisette P7 from Fritsch) for 240 minutes at 900 rotations per minute (rpm).

The grinding bowl was reinserted into the Ar-filled Flandschuh box and opened there. The ground product was separated from the grinding media by sieving.

Yield: 4.1 g of fine powder

EXAMPLE 2 Production of a Composite Cathode Containing Lithium Hydroxide by a Solvent-Based Process (Transition Metal Oxide as Conductivity Improver)

1.2 g of cobalt chloride (97% from Aldrich), 0.69 g of lithium peroxide (> 93% from Albemarle Germany) and 3.6 g of anhydrous lithium hydroxide powder (Albemarle Germany) were dissolved or suspended in 50 ml of anhydrous ethanol and suspended using a high-energy stirrer ( Ultraturrax IKA T 65) homogenized for 15 minutes. The resulting suspension was magnetically stirred at RT for a further 4 h and then filtered.

The filter residue was first predried in vacuo and then sintered for 5 hours at 300 ° C. in an oxygen atmosphere.

Yield: 3.6 g of fine powder

The powder contains 15% Co ₃ 0 ₄ and about 73% LiOH; the rest at 100% consists essentially of lithium oxide.

Claims

1 . A process for producing a rechargeable high-energy battery with an anion-redox-active composite cathode, characterized in that it contains lithium hydroxide as an electrochemically active component, which is mixed and contacted with electronically or mixed conductive transition metals and / or transition metal oxides, so that an electronically or mixed -conductive network is formed, this mixture is applied to a current collector, and the composite cathode formed in this way is introduced into a cell housing together with a separator, a lithium-conductive electrolyte and a lithium-containing anode, so that an electrochemical cell is present and this at least undergoes a first formation cycle.

2. The method according to claim 1, characterized in that the lithium hydroxide is mixed with other lithium oxygen compounds selected from lithium oxide, lithium peroxide and lithium superoxide, the proportion of LiOH in the electrochemically unchanged composite cathode material, based on the total content of lithium oxygen compounds, at least 10 mol%, preferably at least 30 mol%.

3. The method according to claim 1 or 2, characterized in that the finely divided, electronically or mixed-conductive network components on the one hand and the cathode active materials based on lithium oxygen compounds selected from LiOH, U2O, L12O2 and L1O2 on the other hand in a molar ratio from 1: 100 to 1: 1, preferably 1:50 to 1: 1, 5, the electronic conductivity of the materials forming the network at room temperature at least 10 ⁷ S / cm, preferably at least 10 ⁶ S / cm and particularly preferably is at least 10 ⁵ S / cm.

4. The method according to claim 1 to 3, characterized in that the transition metal particles preferably from elements of the 3rd to 12th group of the Periodic Table of the Elements, particularly preferably M = Sc, Ti, Zr, Hf, V, Cr, Mo, W, Mn, Fe, Co, Ni, Cu, Ag, Zn and from the rare earth metals La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Tm, Yb and Lu or any mixture of the above transition metals.

5. The method according to claim 1 to 4, characterized in that the conductive

Transition metal oxides are selected from: binary metal oxides, layer-structured lithium metal oxides, spinel-structured

Lithium metal oxides, inverse spinel structured lithium metal oxides and / or olivine structured lithium metal oxides.

6. The method according to claim 5, characterized in that the binary metal oxides are selected from titanium oxides (TiO, T1 ₂ O ₃ ), vanadium oxides (V ₂ O ₃ , VO, V0 ₂ ), iron oxides (Fe30 ₄ , FeO), cobalt oxides (C0O2, Co ₃ 0 ₄ ), N12O3, manganese oxides (Mhq2, Mn ₃ 0 ₄ ), chromium oxides (CrC> 2, Cr ₃ 0 ₃ ), NbO; the layer-structured lithium metal oxides made of L1C0O2, LiNiCte, Li (Ni, Mn, Co) 02, L1V ₃ O ₈ ; the spinel-structured lithium metal oxides from LiMn ₂ 0 ₄ , LiMnNi0 ₂ , LiNio _.5 Mni _.5 0 ₄ ,, L1V ₃ O ₅ ; the inverse spinel structured lithium metal oxide from LiNiV0 ₄ , LiCoV0 ₄ and the olivine structured lithium metal oxides from LiFeP0 ₄ , LiVP0 ₄ .

7. The method according to claim 1 to 6, characterized in that the

Transition metal particles and / or the conductive

Transition metal oxide compounds and the electrochemically active lithium oxygen compounds are present in finely divided, amorphous or nanoparticulate form with particle dimensions in the range from 0.1 to 100 nm, preferably 1 to 30 nm, in homogeneously mixed form.

8. The method according to claim 1 to 7, characterized in that metallic lithium is used as anode, the lithium being present either as a sheet or as a powder electrode or as an alloy with a metal selected from silicon, tin, boron and aluminum.

9. The method according to claim 1 to 8, characterized in that in the anode before the first discharge cycle, a molar amount of electrochemically activatable, from the anode electrochemically extractable lithium is used, which is at least half, preferably at least the same and particularly preferably at least twice the molar amount corresponding to the LiOH content in the composite cathode.

10. The method according to claim 1 to 9, characterized in that non-metal-based conductivity improvers and binders are used in the anion-redox-active composite cathode and optionally also in the anode.

1 1. A method according to claim 10, characterized in that graphitic materials such as graphite, hard carbon, carbon black and graphene are used as non-metal-based conductivity improvers.

12. The method according to claim 1 to 1 1, characterized in that both the anion-redox-active composite cathode and the anode are compressed by a pressing process or calendering.

13. The method according to claim 1 to 12, characterized in that the solid components of the anion-redox-active composite cathode by a Mahlpro zeß, preferably using a high energy mill, crushed and brought into close contact with each other.

14. High-energy battery with anion-redox-active composite cathode, characterized in that the cathode before the first electrochemical discharge consists of a composite material which contains at least lithium hydroxide as an electrochemically active component, and optionally further lithium oxygen compounds selected from lithium oxide, lithium peroxide and / or lithium superoxide embedded in contains an electronically or mixed conductive network, which consists of electronically conductive

There are transition metals and / or transition metal oxides, the electronically or mixed-conductive network components on the one hand and the cathode active materials based on

Lithium oxygen compounds selected from LiOH, U2O, L12O2 and L1O2, on the other hand, are present in a molar ratio of 1: 100 to 1: 1, preferably 1:50 to 1: 1.5. High-energy battery according to claim 14, characterized in that the anode contains at least one lithium-donating component or compound with an electrochemical potential of <2 V against the Li / Li ⁺ reference electrode, selected from metallic lithium, a lithium-containing metal alloy, one Lithium nitrido transition metalate or composite materials, the electrochemically active component of which is a metal nitrogen compound, which is embedded in a transition metal-containing, electronic or mixed-conductive network.