Preparation process of perlithiated lithium metal oxides

Abstract

The present invention relates to a process for preparing perlithiated transition metal oxides, such as LiNiO, from a mixture of lithium peroxide and at least one transition metal oxide or manganese-containing spinel compound in a two-stage calcination process with respect to temperature and atmosphere composition.

Description

[Technical Field]

[0001] The present invention relates to an economical process for preparing perlithiated lithium metal oxides from lithium peroxide and at least one transition metal oxide, and their uses. Perlithiated lithium metal oxides are used as cathode additives for the purpose of prelithiation in lithium-ion batteries. [Background technology]

[0002] In terms of energy density, lithium-ion batteries represent the upper limit of battery technology currently available on an industrial scale. Therefore, they are rapidly increasing in use in both stationary and mobile galvanic energy storage systems. The increasing demand for range in mobile applications, particularly in automobiles and other transportation technologies, necessitates ever-increasing energy densities. This trend necessitates the use of electrode materials with the highest possible capacity and electrode pairs capable of achieving the highest possible voltages.

[0003] Modern high-power lithium batteries use high-voltage cathode materials, primarily nickel-rich materials Li(Ni x Mn y Co z )O2(x+y+z=1 and Ni>0.33), or LiMn 1.5 Ni 0.5 These include high-voltage spinel compounds such as O4. Graphite-based materials, with a theoretical capacity of 372 mAh / g, are typically used as anode materials. To increase this capacity, lithium-alloyable materials, especially Si-based powders, are mixed with the graphite.

[0004] The usable energy content of lithium-ion batteries (LIBs) is degraded by a series of decomposition and parasitic reactions. The most important parasitic reaction in LIBs involves the loss of "active lithium" during the filming of the negative electrode, i.e., the formation of a "solid electrolyte layer (SEI)" on the surface of the anode particles during the initial charge / discharge cycles. Graphite anodes are known to typically consume approximately 3-5% of the total lithium introduced into the battery cell along with the cathode material to form an SEI that remains stable for the remainder of the process. The lithium "consumed" by the formation of the protective layer, i.e., converted to a form that is no longer electrochemically active, is insufficient for the full utilization and further discharge of the cathode material during cycling.

[0005] When alloyable anode components such as Si or Sn-based powders are used, the irreversible initial losses are even significantly higher, and Li losses can account for up to 20% depending on their proportion in the anode material.

[0006] To compensate for these losses, metallic lithium or various Li-rich compounds can be added to the cathode and / or anode materials. Such prelithiation agents provide a stock of lithium during the "formation" of the battery cell (i.e., the first charge / discharge cycle) and decompose to form volatile by-products or primarily electrochemically inactive solids. To keep this proportion of inactive solids as low as possible, the activatable Li content must be as high as possible. This is the case for many so-called perlithiated lithium metal oxides. Perlithiated metal oxides, sometimes alternatively referred to as lithium-rich metal oxides, are lithium-containing oxide compounds that have an increased lithium content compared to standard LIB cathode materials and make this additional content available during the first charge / discharge cycle to compensate for the irreversible lithium loss at the anode side. Because this process is irreversible, perlithiated metal oxides cannot be recovered during subsequent cycles.

[0007] To balance the charge, the transition metal M is coupled to the corresponding LIB cathode material. In comparison, they exist in correspondingly reduced forms.

[0008] This is illustrated in the following table: [Table 1]

[0009] Perlithiated lithium metal oxides may release lithium from their structure (usually irreversibly) when the battery is discharged, forming oxide compounds in which the included redox-active metals are oxidized accordingly.

[0010] The table above lists the final stages of perlithiation. Starting with a "normal" cathode material, there are all intermediate stages between the "normal form" and the perlithiated form in terms of lithium content. These are formally formed by lithium incorporation into the host material, mostly under reducing conditions, i.e., in a non-oxidizing atmosphere. For purposes of this invention, all of the above LIB cathode materials with lithium contents exceeding normal lithiation are considered "perlithiated" (see also U.S. Pat. No. 6,652,605). Unlike LIB cathode materials, perlithiated metal oxides are generally not stable in air or water; that is, they must be handled under inert gas to avoid undesired changes.

[0011] These have the following composition: Li 2+x FeO4(x=0~3);Li 1+x NiO2(x=0~1);Li 1+x CoO 1.5+0.5x (x=0 to 5); Perlithiated spinel compound Li 1+x Mn2O4(x=0>~1);Li 1+x Ni 0.5 Mn 1.5 O4 (x = 0 > 1). In the case of Li6CoO4, this compound formally absorbs additional oxygen during lithium absorption (F. Hortstige, Batteries 2018, 4, 4).

[0012] The preparation of perlithiated metal compounds is typically carried out by reacting a lithium base salt such as lithium hydroxide monohydrate, lithium carbonate, or preferably lithium oxide, with the corresponding transition metal hydroxide or oxide, or a mixture of different transition metal hydroxides or oxides.

[0013] For example, prior art perlithiated lithium nickel oxide (Li2NiO2) according to the state of the art (G. Cedar, Chem. Mater. 2004, 2685) is produced by reacting lithium oxide with nickel in an inert (i.e., oxygen-free) atmosphere.

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[0014] For this purpose, nickel oxide is first ground with lithium oxide in a ball mill, then pelletized and calcined at 650 °C for 24 hours under an inert argon atmosphere. Perlithiated cobalt oxide Li6CoO4 is prepared by solid-solid reaction by reacting CoO and Li2O at 900 °C under a nitrogen atmosphere (Yinging Zhou, dissertation 2021, https: / / doi.org / 10.14989 / doctor.k22548). Li5FeO4 is prepared from Li2O and Fe3O4 under an air atmosphere at 500 °C or 800 °C (MV Blanco et al., Chem. Eng. J. 354, 2018, 370-7), as follows: Fe3O4+7.5Li2O+0.5O2→3Li5FeO4 Alternatively, it can be synthesized from a ground mixture of Fe2O3 and Li2O by heating first to 450°C and then to 750°C under inert conditions (WM Dose et al., J. Electrochem. Soc. 2020, 167 160543). Fe2O3+5Li2O→2Li5FeO4

[0015] Li1+x Ni 0.5 Mn 1.5 Perlithiated spinels such as O4 are often used in the corresponding conventional cathode materials, LiNi 0.5 Mn 1.5 It is prepared by reacting O4 with a lithium source at 600 °C under reducing conditions (G. Gabrielli et al., J. Power Sources,351,2017,35).

[0016] A drawback of these described processes is the use of LiO, which can only be produced by very complex processes, for example, by combustion of metallic lithium or by pyrolysis of lithium carbonate at temperatures above 900 °C or a mixture of lithium carbonate and carbon black at temperatures above 700 °C. Since lithium carbonate is already molten at 720 °C, pyrolysis of lithium carbonate usually results in a solidified melt or at least a high-strength sintered product, which must be broken and crushed in a complex process. This mechanical crushing and subsequent screening must exclude air components (H2O and CO2), which are reactive with lithium oxide, making the process very expensive.

[0017] In contrast, the thermal decomposition of lithium peroxide, LiO, to form LiO requires relatively low temperatures of about 300-400°C, well below the melting point.

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[0018] The drawback of this production process is that the LiO produced from LiO must be isolated as is, which must then be mixed with NiO or another transition metal oxide or hydroxide in a separate reaction step and then thermally decomposed (KR101887171 B1 ).

[0019] The goal to solve A method is desired that allows for the synthesis of perlithiated lithium metal oxides, such as LiNiO, from LiO and a transition metal oxide, such as NiO, via a low-cost synthesis, preferably a one-pot synthesis.

[0020] According to the present invention, the object is to a) Lithium peroxide Li2O2 is a compound containing at least one transition metal oxide M a O b or mixed with manganese-containing spinel compounds, followed by b) the mixture is fired, Here, M of the transition metal oxide is selected from Fe, Ni, Co, and Mn, a is a number from 1 to 3, and b is a number from 1 to 4. The manganese-containing spinel compounds are LiMn2O4 and LiNi 0.5 Mn 1.5 Selected from O4, The mixture is successively fired at at least two successively different temperature levels; In b), the first temperature level is in the range of 280-450°C, and the second temperature level is in the range of 500-950°C.

[0021] In this process, a mixture of powdered lithium peroxide and at least one desired metal oxide or manganese-containing spinel compound is mixed, preferably under grinding conditions, with the at least two components—lithium peroxide and at least one transition metal oxide or manganese-containing spinel compound, respectively—then compacted or pressed, preferably by applying external pressure.

[0022] The mixture is then converted to perlithiated lithium metal oxide by calcination in two process steps at two different temperature levels, which is preferably carried out in a one-pot process.

[0023] Lithium peroxide with a high specific surface area is preferably used, preferably at least 1 m 2 / g, particularly preferably at least 2m 2 / g.

[0024] Preferably, the first temperature is in the range of 300 to 400°C, and preferably, the second temperature is in the range of 600 to 900°C.

[0025] Preferably, the firing time at the first temperature is in the range of 0.5 to 20 hours, more preferably 1 to 10 hours, and most preferably 2 to 10 hours.

[0026] Regardless, the duration of firing at the second temperature is preferably in the range of 1 to 96 hours, preferably 1 to 72 hours, more preferably 2 to 72 hours, and even more preferably 2 to 48 hours.

[0027] During firing at the first temperature, lithium oxide Li2O is formed with the release of oxygen, which is evacuated from the system either in a vacuum or by overflowing with an inert gas (e.g., nitrogen or argon).

[0028] During calcination at the second temperature, the formed lithium oxide, Li2O, reacts with at least one transition metal oxide or manganese-containing spinel compound to form a perlithiated lithium metal oxide.

[0029] The firing at the first and second temperatures is suitably carried out under vacuum or inert gas atmosphere, the vacuum being preferably 1 to 10,000 Pa (0.01 to 100 mbar), in particular 5 to 5,000 Pa (0.05 to 50 mbar), the inert gas atmosphere being formed by an inert gas or gas mixture excluding water / humidity and CO, the inert gas / mixture preferably comprising nitrogen, argon or helium, and the firing at the second temperature being additionally carried out mainly excluding oxygen.

[0030] The two calcination steps may preferably be carried out at different temperature levels in the same reaction vessel, either by temporal and / or spatial separation measures to ensure the different temperature and atmospheric condition requirements of the two reaction steps.

[0031] Surprisingly, we found that the decomposition of lithium peroxide under oxygen release does not result in undesired oxidation of the metal oxide or manganese-containing spinel compounds present in the mixture. Therefore, the transition metal-containing oxide compounds are inert under the first calcination temperature levels of 280-450°C required for decomposition of the peroxide under vacuum or inert gas flow (e.g., nitrogen). Thus, a second calcination step at a higher temperature of at least 500-950°C can yield the desired perlithiated metal oxide compounds in high purity.

[0032] According to the present invention, the calcination is carried out in a corrosion-resistant and high-temperature resistant vessel or reactor, the construction material of which is in particular a high-temperature resistant material resistant to corrosion by basic lithium salts, preferably a metallic material selected from high-temperature resistant Cr- and / or Al-containing materials (in particular Cr- and / or Al-containing nickel-based alloys, Ni- and Cr-containing austenitic steels, low-Ni or Ni-free Cr- and Al-containing ferritic steels, or chromium-containing mixed austenitic-ferritic steels), oxide ceramics (in particular AlO, lithium aluminate ceramics (LiAlO), Ce-based ceramics (in particular Ce-stabilized ZrO), non-oxide ceramics (in particular carbides, preferably SiC, BC, TiC; nitrides, preferably TiN, AlN; and borides, preferably NbB, BN, Al-infiltrated TiB, "TiBAl").

[0033] The process of the present invention can be carried out under static conditions, in which a mixture of transition metal oxide and Li2O2 in a corrosion-resistant shell or as bulk on a belt is first heated to a temperature in the range of 280-450°C under vacuum conditions or in an inert gas atmosphere, and the thermal decomposition of Li2O2 occurs accompanied by the release of oxygen. After the decomposition of Li2O2 is complete and the formed oxygen is removed from the system, a higher temperature required for the formation of the perlithiated metal oxide is set in the range of 500-950°C while ensuring an oxygen-free atmosphere.

[0034] Alternatively, the process according to the invention can be carried out under moving-bed conditions in a reactor that ensures continuous mixing of the reaction mixture. In this case, the reactor is preferably a continuously operated, heatable rotary tube with at least two different temperature zones: in the inlet region for the raw material mixture, the temperature is 280-450°C; in the rear region, closer to the product discharge zone, the temperature is 500-950°C; in the 500-950°C temperature zone, conditions suitable for the formation of superlithiated lithium metal oxide are established by supplying an excess of inert gas or an inert gas mixture substantially free of O, CO, and HO. In this process, the inert gas or gas mixture is preferably flowed counter to the direction of movement of the solid reaction mixture.

[0035] The mixture of lithium peroxide and at least one transition metal oxide is preferably used at an energy input of about 10 to 500 kW / m 3 or in a mill, in particular an impact rotary mill (impact mill), grinding media mill or pin mill. .

[0036] The subsequent compression is preferably carried out, for example, during a tableting process, i.e., by applying pressure to the powder mixture placed in a die using a moving die, or by using a rolling mill, i.e., by two rollers rotating against each other, or by a powder press. The pressing pressure is 0.001 to 100 kbar, preferably 0.01 to 50 kbar.

[0037] The transition metal oxides used in the process of the present invention are preferably selected from NiO, CoO, Fe2O3, Fe3O4 and FeO.

[0038] The molar mixing ratio of Li2O2 to transition metal oxide in the process according to the invention is usually in the range of 0.6:1 to 3:1, preferably 0.9:1 to 3:1, and in particular 1:1 when M=Ni. For example, a ratio of Fe=5:1, Ni=2:1, and Co=6:1 is preferred.

[0039] The perlithiated lithium metal oxides prepared according to the present invention are preferably LiFeO, LiNiO, LiCoO, or perlithiated manganese-containing spinel compounds, especially Li 1+x Mn2O4 or Li 1+x Ni 0.5 Mn 1.5 O4 (wherein x=0 or more and 1 or less).

[0040] Particularly preferably, the perlithiated lithium metal oxide is Li2NiO2, and the mixed molar ratio of Li2O2:NiO is 1:1.

[0041] The perlithiated metal oxide compounds prepared by the method according to the present invention can be used for prelithiation in the manufacture of lithium ion batteries.

[0042] The process according to the present invention is carried out as described in more detail below.

[0043] To carry out the process according to the invention, a mixture of lithium peroxide Li2O2 and transition metal oxide(s) M, preferably powdered, is used. a O b are first mixed. For the mixing process, different equipment and process technologies can be applied. Approximately 10 to 500 kW / m 3 Particularly suitable are rotary mixers, which provide an energy input in the range of 1000 to 15000 kcal / min. Among rotary mixers, both those with a rotating vessel and those with a rotating mixing tool are suitable. What is important is a sufficiently powerful energy input. Such units, which can be designed according to the countercurrent or crossflow principle, are offered, for example, by Eirich under the name "Intensive Mixer". Other suitable mixer designs are paddle dryers with an additionally installed knife mill, for example, offered by Lodige, and intensive mixers with high-speed rotors, for example, available from Hosokawa under the brand name "Nobilta".

[0044] Most types of mills are suitable for intensive mixing, especially beater rotary mills (impact mills), grinding media mills, or pin mills. Knife mills or cutter mills can also be used to a limited extent. In grinding media mills, mixing is carried out in a grinding drum using hard grinding media such as balls or rods made of metal (steel or nickel-based alloys) or hard ceramics (metal oxides, metal carbides, metal nitrides, etc.). The Vickers hardness of the grinding vessel and grinding media is at least 400, preferably at least 600. Materials made of stainless steel or metal oxides, such as aluminum oxide or zirconium oxide, are particularly preferred. Ball mills, rod mills, or hammer mills can be used.

[0045] For subsequent compaction, a uniaxial powder press, such as those available from Frey & Co., can be used. On a small scale, a simple punch / die system is preferred. For larger powder quantities, axial powder presses with servomotor, mechanical, or hydraulic compaction, such as those offered by Dorst Technologies, are suitable.

[0046] The subsequent thermally induced transformation (calcination) is carried out at two different temperature levels and in different atmospheres.

[0047] This is illustrated by the example of the production of perlithiated Li-nickel oxide.

[0048] In the first step, a low-temperature step in the range of 280 to 450°C, preferably 300 to 400°C, particularly 320 to 380°C, only the lithium peroxide in the mixture is converted to lithium oxide. Li2O2 / NiO → Li2O / NiO+1 / 2O2

[0049] The evolved oxygen is removed from the reactor system either by a vacuum process, i.e., under constant reduced pressure (dynamic vacuum), or by a carrier gas stream consisting of a gas mixture free of HO and CO. Suitable carrier gas streams are inert gases (commercial quality N, Ar, He) or dry CO-free air.

[0050] In the second step, the mixture, consisting of an approximately equimolar mixture of lithium oxide and nickel oxide, is calcined at a higher temperature to form the desired superlithiated nickel oxide in a solid / solid reaction. Li2O / NiO → Li2NiO2

[0051] This second reaction step requires higher temperatures of 550-750°C, preferably 600-700°C, and is carried out under vacuum conditions or even under an inert gas atmosphere. This gas atmosphere, in contrast to the first calcination phase, must therefore be oxygen-free (i.e., a gas atmosphere free of H2O, CO2 and O2 is ensured). Suitable inert gases are, for example, nitrogen and noble gases such as argon or helium. According to the invention, two different process variants are conceivable for the production of perlithiated metal oxides:

[0052] 1.Static process: The mixture of transition metal oxide and Li2O2 is first heated in corrosion-resistant trays or in bulk on a conveyor belt to temperatures between 280 and 450 °C, where thermal decomposition of the peroxide occurs with the release of O2. This initial reaction stage requires either vacuum conditions or an inert gas atmosphere, i.e., a gas or gas mixture (free of H2O and CO2) that is non-reactive with the reactants and products.

[0053] After the release of O2 gas is complete, the temperature is raised to 500-950°C, which is the temperature required for the production of perlithiated lithium transition metal oxides. This reaction step is also carried out under vacuum conditions or in an oxygen-free inert gas atmosphere (i.e., a gas atmosphere that does not contain H2O, CO2, or O2). Suitable inert gases include nitrogen and noble gases such as argon or helium.

[0054] 2. Moving bed process: This transformation is preferably carried out continuously in a reactor that ensures mixing. This reactor is preferably a rotary tube with two different temperature zones: in the inlet region of the raw material mixture, the temperature is between 280 and 450°C, while in the rear region, i.e., the region closer to the product outlet, the temperature is between 280 and 450°C, which is the temperature of the lithium oxide formed in the first zone and at least one The temperature level allows for a synthesis reaction between the transition metal oxide and the desired superlithiated lithium metal oxide. For the synthesis of Li2NiO2, this is in the range of 550-950°C. To avoid undesirable oxidation of the transition metal oxides used at these higher temperature levels (e.g., from Ni(II) to Ni(III) or Ni(IV)), a reducing (i.e., oxygen-free) atmosphere must be established in the high-temperature zone. This is ensured by passing an oxygen-free inert gas stream countercurrently (i.e., opposite to the direction of movement of the moving bed of solids) over the reaction mixture.

[0055] The two calcination steps are carried out in an apparatus whose product-facing surfaces are made of a material resistant to high temperatures and corrosion from basic lithium salts. A wide range of metallic materials can be used for this purpose, selected from high-temperature-resistant Cr- and / or Al-containing materials. In particular, Cr- and / or Al-containing nickel-based alloys, Ni- and Cr-containing austenitic steels, low- or Ni-free Cr- and Al-containing ferritic steels, and chromium-containing mixed austenitic-ferritic steels can be used as container materials. The chromium content of alloys suitable for use is at least 15% by weight, preferably at least 20% by weight, and particularly preferably at least 30% by weight. If the Al content is at least 1% by weight, the chromium content can be significantly lower (at least 5% by weight). A preferred Al content is at least 1% by weight, and particularly preferably at least 2% by weight. In addition to chromium and aluminum, metallic alloys usable in the process according to the invention can contain niobium, titanium, tantalum, and / or silicon, in proportions of up to 10% by weight in each case. Low-Mo alloys are preferably used. The Mo content is less than 2% by weight, preferably less than 1% by weight.

[0056] The following commercially available metallic materials are particularly advantageous for use: Nickel-based alloys: Inconel600, Inconel601, Inconel693, Inconel702, Inconel800, Inconel825, Incoloy901, Nichrome, Nichrome V, Nimonic75, Nimonic80A, Nimonic90, RA602CA / Alloy 602CA, Alloy X and equivalent grades; Austenitic steels: SS347 (1.4550), 253MA (1.4835), Nitronic50, 310S, 316L, SS310, SS304, RA253MA, etc.; Ferritic steels: Kanthal (e.g., Kanthal A1, Kanthal AF, Kanthal D (FeCrAl)), PM2000, Incoloy MA956, etc.

[0057] Both solid metal materials selected from the above-mentioned group of materials and appropriately coated high-temperature resistant black steel or stainless steel can be used. The anti-corrosion coating on the side facing the product contains at least 10% by weight, preferably at least 30% by weight, of chromium. Furthermore, this material can contain the elements Ni, Fe, Nb, Al, Ti, Ta and Si in a maximum content of each of 10% by weight.

[0058] The thickness of the chromium-containing anticorrosive coating is at least 5 μm, preferably at least 10 μm. The coating thickness is measured by electron microscopy. For example, austenitic steels with only moderate corrosion resistance, such as 1.4401, can be significantly improved in terms of corrosion resistance by applying a 50 μm-thick Cr- and Al-containing coating. Such coating processes can be achieved via various electrochemical or physical techniques, such as the pack cement process (Kim, Mater. Transact. 43, 2002, 593).

[0059] In addition to the above-mentioned metallic materials, certain oxide ceramics (e.g., Al2O3, lithium aluminate ceramics (LiAlO2), or Ce-based ceramics (e.g., Ce-stabilized ZrO2) and non-oxide ceramics (e.g., carbides such as SiC, BC, TiC, etc.; nitrides such as TiN, AlN, etc.; borides such as NbB2, BN, Al-infiltrated TiB2, "TiBAl" etc.) can also be used as container materials. Materials coated with the above-mentioned ceramics (preferably LiAlO2), for example, high-temperature resistant steels, can also be used.

[0060] Carbon-based materials such as graphite (carbon graphite, hard carbon) and pure carbon (glass carbon), which has a disordered graphitic structure and ceramic properties, can be used to a limited extent. However, the use of carbon-based materials in high-temperature calcination processes, i.e., processes at temperatures above approximately 400°C, requires particularly rigorously controlled inert conditions, i.e., the complete exclusion of oxidizing agents such as oxygen or other oxygen donors such as water or CO2. Because oxygen is released in the initial reaction substep, a certain amount of combustion is almost unavoidable over longer periods. Therefore, oxide-stabilized graphite materials, which exhibit significantly lower combustion than high-purity graphite when in contact with ambient air, are preferred (DV Savchenko, New Carbon Materials 2012, 27, 12-18). Graphite materials are high-temperature resistant materials produced from raw materials such as petroleum coke, pitch coke, carbon black, and graphite via a filler / binder system. They are first crushed to a defined particle size distribution, mixed at high temperature, compacted in a press into compacts, and then carbonized by a high-temperature pyrolysis process.

[0061] Carbon-based materials can be used as solid reaction vessels, or hollow bodies coated or lined with graphitic materials (e.g., metal tubes lined with graphitic foil) can be used.

[0062] The perlithiated metal oxide compounds produced in accordance with the present invention are mixed with a lithium-ion battery cathode material for prelithiation purposes and processed to form a positive electrode strip. As a component of the positive electrode, the perlithiated metal oxide compounds decompose to release lithium during the first charge-discharge cycle. [Example]

[0063] overview: All handling of lithium sources (lithium peroxide and lithium oxide) was carried out under inert conditions, i.e., inside an Ar-filled glove box.

[0064] The reaction products were characterized by powder diffraction (XRD) using a Bruker instrument (AXS D2 Phaser A26).

[0065] The determination of the specific surface area of ​​the lithium compounds used was carried out by gas adsorption according to the method of Stephen Brunauer, Paul Hugue Emmett and Edward Teller ("BET").

[0066] Example 1 Formation of Li2NiO2 from NiO and Li2O2 In an Ar-filled glovebox, 1.90 g (41.4 mmol) of lithium peroxide (97%, BET = 7.6 m 2 / g, supplier Albemarle Germany) and 3.09 g (41.4 mmol) of nickel(II) oxide (NiO green, Sigma Aldrich, catalogue number SIAL399523-100G) were mixed and pre-ground in an agate mortar and then crushed in a Fritsch planetary ball mill (Pulverisette 7, Z The powder mixture was ground together in an Easy GTM grinding bowl manufactured by ZrO2. For grinding approximately 5 g of powder mixture, 12 ZrO2 balls with a diameter of 10 mm were used. The grinding time was 2 hours at 600 rpm. A brownish mixture was obtained, from which the balls were removed by sieving.

[0067] 1.0 g of the ground mixture was loaded into a die set set up on a Specac and compressed into tablets at a contact pressure of 500 kg (equivalent to approximately 620 bar) for 15 minutes.

[0068] The tablets were then fired in aluminum oxide crucibles in a tube furnace under a slight nitrogen flow (20 L / h). The heated nitrogen flux furnace tube was made of quartz glass. It was first heated to 300°C and held at this temperature for 2 hours. The furnace temperature was then increased to 700°C within approximately 30 minutes and held at this temperature for 24 hours.

[0069] After cooling to room temperature, the crucible was placed in an air-excluded glove box. The tablets remained intact and were black in color.

[0070] Yield: 0.87 g (weight loss 13.1%, corresponding to 99% of theory). XRD: Mixture of Li2NiO2, 23 wt%; NiO, 51 wt%; Li2O, 26 wt%.

[0071] Example 2 (Comparative Example) Formation of Li2NiO2 from NiO and Li2O In an Ar-filled glove box, 1.429 g (47.8 mmol) of lithium oxide (99%, BET = 2.4 m 2 3.571 g (47.8 mmol) of nickel(II) oxide (NiO green, Sigma Aldrich catalog number SIAL399523-100G) were mixed and pre-ground in an agate mortar and then ground together in a Fritsch planetary ball mill (Pulverisette 7, Easy GTM grinding bowl made of ZrO). For grinding approximately 5 g of powder mixture, 12 ZrO balls with a diameter of 10 mm were used. The grinding time was 2 hours at 600 rpm. A brownish-gray mixture was obtained, from which the balls were removed by sieving.

[0072] 1.0 g of the ground mixture was loaded into a die set set up on a Specac and compressed into tablets at a contact pressure of 500 kg (equivalent to approximately 620 bar) for 15 minutes.

[0073] The tablets were then fired in aluminum oxide crucibles in a tube furnace under a slight nitrogen flow. The heated nitrogen flow furnace tube was made of quartz glass. It was first heated to 300°C and held at this temperature for 2 hours. The furnace temperature was then increased to 700°C and held at this temperature for 24 hours.

[0074] After cooling to room temperature, the crucible was placed in an air-excluded glove box. The tablets remained intact and were black in color.

[0075] Yield: 1.0 g (no significant weight loss). XRD: Mixture of Li2NiO2, 11 wt%; NiO, 60 wt%; Li2O, 29 wt%.

[0076] The experiment showed that in the process control according to the present invention, Li2O2 was used to obtain the desired Li2NiO2 without changing the oxidation state of NiO used by the oxygen generated during the first firing step. Surprisingly, the conversion using Li2O2 is more than two times higher than that observed using Li2O.

[0077] The degree of conversion can be further increased by optimizing the experimental conditions, especially by extending the calcination time.

Claims

1. A process for preparing lithium metal peroxide by reacting lithium peroxide with at least one transition metal oxide or manganese-containing spinel compound, a) Lithium peroxide Li 2 O 2 This includes at least one transition metal oxide M a O b Alternatively, it is mixed with a manganese-containing spinel compound, and subsequently b) The mixture is calcined, Here, M of the transition metal oxide is selected from Fe, Ni, Co, and Mn, and the manganese-containing spinel compound is LiMn 2 O 4 and LiNi 0.5 Mn 1.5 O 4 selected from, a is a number from 1 to 3, b is a number from 1 to 4, The mixture is fired continuously at at least two consecutively different temperature levels. b) The process characterized in that the first temperature level is in the range of 280 to 450°C and the second temperature level is in the range of 500 to 950°C.

2. The process according to claim 1, characterized in that the first temperature is preferably in the range of 300 to 400°C, the second temperature is preferably in the range of 600 to 900°C, the firing time at the first temperature is preferably in the range of 0.5 to 20 hours, particularly in the range of 1 to 10 hours, and the firing time at the second temperature is independently preferably 1 to 96 hours, preferably 1 to 72 hours, more preferably 2 to 72 hours, and even more preferably 2 to 48 hours.

3. The firing at the first and second temperatures is carried out under vacuum or inert gas atmosphere, the vacuum being preferably 1 to 10,000 Pa (0.01 to 100 mbar), particularly 5 to 5,000 Pa (0.05 to 50 mbar), and the inert gas atmosphere being water / humidity and CO 2 The process according to any one of claim 1 or 2, characterized in that it is formed by an inert gas or mixture of inert gases, the inert gas / gas mixture preferably includes nitrogen, argon, or helium, and the calcination at the second temperature is carried out in addition, excluding oxygen.

4. The process according to claim 1 or 2, characterized in that the two firing steps are carried out at different temperature levels in the same reaction vessel, and the requirements for the different temperature and atmospheric conditions of the two reaction steps are ensured by either temporal or spatial separation measures.

5. Minimum 1m 2 / g, preferably a minimum of 2m 2 The process according to claim 1 or 2, characterized by using lithium peroxide having a specific surface area of ​​1 / g.

6. The firing is carried out in a corrosion-resistant and high-temperature resistant reactor, and the constituent materials of the reactor are, in particular, high-temperature resistant materials that are corrosion-resistant to basic lithium salts, preferably high-temperature resistant Cr and / or Al-containing materials (in particular Cr and / or Al-containing nickel alloys, Ni and Cr-containing austenitic steel, low-Ni or Ni-free Cr and Al-containing ferritic steel, or chromium-containing mixed austenitic-ferritic steel), oxide ceramics (in particular Al 2 O 3 Lithium aluminate ceramic (LiAlO 2 ), Ce-based ceramics (especially Ce-stabilized ZrO 2 ), non-oxidizing ceramics (especially carbides, preferably SiC, BC, TiC; nitrides, preferably TiN, AlN; and borides, preferably NbB) 2 , BN, Al infiltrated TiB 2 The process according to claim 1 or 2, characterized in that the material is a metallic material selected from "TiBAl".

7. The process is carried out under static conditions, and the transition metal oxides and Li are used as bulk in a corrosion-resistant shell or on a belt. 2 O 2 The mixture is first heated to a temperature of 280-450°C under vacuum conditions or in an inert gas atmosphere, and Li 2 O 2 The thermal decomposition of Li occurs accompanied by the release of oxygen. 2 O 2 The process according to claim 1 or 2, characterized in that, after the decomposition of is completed, the high temperature of 500 to 950°C required for the formation of the superlithiated metal oxide is set while ensuring an oxygen-free atmosphere.

8. The process according to claim 1 or 2, characterized in that it is carried out under moving bed conditions in a reactor to ensure continuous mixing of the reaction mixture.

9. The reactor is preferably a continuously operated, heatable rotating tube having at least two different temperature zones, wherein the temperature in the inlet region of the raw material mixture is 280 to 450°C, and the temperature in the rear region, closer to the product discharge region, is 500 to 950°C, and in the 500 to 950°C temperature zone, an inert gas or O 2 CO 2 and H 2 The process according to claim 8, characterized in that conditions suitable for the formation of the lithium metal oxide overlithide are set by supplying an excess of an inert gas mixture containing almost no oxygen.

10. The mixture of lithium peroxide and at least one transition metal oxide has an energy input of approximately 10 to 500 kW / m². 3 The process according to claim 1 or 2, characterized in that it is carried out in a rotary mixer or mill, in particular in an impact rotary mill (impact mill), a grinding media mill or a pin mill.

11. The process according to claim 1 or 2, characterized in that the mixture comprising lithium peroxide and at least one transition metal oxide or manganese-containing spinel compound is compressed before calcination using a contact pressure in the range of 0.001 to 100 kbar, preferably 0.01 to 50 kbar.

12. The transition metal oxide is nickel, manganese, cobalt, or iron oxide, preferably NiO, CoO, Fe 2 O 3 Fe 3 O 4 and FeO, particularly preferably NiO, CoO and Fe 2 O 3 The process according to claim 1 or 2, characterized by being selected from.

13. Li to the transition metal oxide 2 O 2 The process according to claim 1 or 2, characterized in that the mixed molar ratio is in the range of 0.6:1 to 3:1, preferably 0.9:1 to 3:1, and particularly 1:1 when M = Ni.

14. The aforementioned lithium metal oxide perlithide is Li 2+x FeO 4 (x=>0~3);Li 1+x NiO 2 (x=>0~1);Li 1+x CoO 1.5+0.5x (x=>0~5);Li 1+x Mn 2 O 4 (x=>0~1);Li 1+x Ni 0.5 Mn 1.5 O 4 (x = greater than 0 to 1), preferably Li 5 FeO 4 Li 2 NiO 2 Li 6 CoO 4 Li 2 Mn 2 O 4 or Li 2 Ni 0.5 Mn 1.5 O 4 Preferably, the lithium metal oxide perlithide is Li 2 NiO 2 Li 2 O 2 The process according to claim 1 or 2, characterized in that the mixed molar ratio of NiO is 1:

1.

15. Use of a hyperlithiated metal oxide compound produced by the process described in claim 1 or 2 for prelithiation in the manufacture of lithium-ion batteries.