METHOD FOR THE PRODUCTION OF A LITHIUM MANGANE NICKELOXIDE CATHOD USING HIGH-PURITY ELECTROLYTIC MANGANE DIOXIDE FOR IMPROVED PERFORMANCE OF ELECTROCHEMICAL CELLS

Abstract

Method for producing a lithium manganese nickel oxide cathode using electrolytic manganese dioxide, the method comprising: Dissolving metallic manganese in acid to obtain a solution containing dissolved manganese; Arranging the solution with dissolved manganese in an electrolytic cell with an anode of the electrolytic cell and a cathode of the electrolytic cell; Applying a current between the anode of the electrolytic cell and the cathode of the electrolytic cell to the solution containing dissolved manganese, the application of the current forming a deposit layer of MnO2 on the anode of the electrolytic cell; Harvesting the formed MnO2 deposition layer from the anode of the electrolytic cell; Producing a manganese precursor by neutralizing the MnO2 deposition layer and grinding the MnO2 deposition layer to form an MnO2 powder; Mixing the manganese precursor with a nickel precursor and a lithium precursor to create a mixture; Calcining the mixture to produce a lithium manganese nickel oxide powder; and Coating a current collector with lithium manganese nickel oxide powder to form the lithium manganese nickel oxide cathode.

Description

INTRODUCTION

[0001] The disclosure generally relates to a process for producing a lithium manganese nickel oxide cathode using high-purity electrolytic manganese dioxide for improved performance of electrochemical cells.

[0002] A battery or battery system comprises one or more battery cells. A lithium-ion cell or lithium-ion battery cell operates such that during a discharge cycle, lithium ions move from an anode to a cathode through an electrolyte. During a charge cycle, lithium ions move in the opposite direction, from the cathode to the anode. An electrolyte is configured to provide a medium through which the lithium ions can move during battery operation.

[0003] Various methods for producing a lithium manganese nickel oxide cathode are known, for example, from CN 1 09 678 216 A, DE 696 32 586 T2, DE 23 32 729 A1, US 2014 / 0 077 127 A1 and US 2010 / 0 239 911 A1. SUMMARY

[0004] According to the invention, a process for producing a lithium manganese nickel oxide cathode with electrolytic manganese dioxide is provided. The process comprises dissolving metallic manganese in acid to produce a solution containing dissolved manganese, placing the solution containing dissolved manganese in an electrolytic cell comprising an anode and a cathode, and applying a current between the anode and cathode of the electrolytic cell to the solution containing dissolved manganese. The application of the current causes a deposition layer of MnO₂ to form on the anode of the electrolytic cell. The process further comprises obtaining or...The process involves harvesting the formed MnO2 deposit layer from the anode of the electrolytic cell, generating a manganese precursor by neutralizing the MnO2 deposit layer and milling the MnO2 deposit layer to form an MnO2 powder, and mixing the manganese precursor with a nickel precursor and a lithium precursor to create a mixture. The process further includes calcining the mixture to produce a lithium-manganese-nickel oxide powder and coating a current collector with the lithium-manganese-nickel oxide powder to form the lithium-manganese-nickel oxide cathode.

[0005] In some embodiments, the production of the manganese precursor also includes calcining the MnO2 powder under atmospheric air or oxygen gas to produce Mn2O3.

[0006] In some embodiments, the calcination of the MnO2 powder includes calcining the MnO2 powder at a temperature of 700 °C to 950 °C for 1 hour to 24 hours.

[0007] In some embodiments, the calcination of the MnO2 powder includes calcining the MnO2 powder at a temperature of 700 °C to 850 °C for 12 hours.

[0008] In some embodiments, the manganese precursor contains alkali metal impurities and alkaline earth metal impurities in amounts ranging from 10 parts by weight to 100 parts by weight, based on one million parts by weight of the manganese precursor.

[0009] In some embodiments, the manganese precursor contains particles with a diameter of at least 100 nanometers.

[0010] In some embodiments, the manganese precursor contains particles with a diameter of 100 to 300 nanometers.

[0011] In some embodiments, the manganese precursor has a particle surface area of ​​0.5 square meters per gram to 5 square meters per gram.

[0012] In some embodiments, calcining the mixture involves heating the mixture at a temperature of 700 °C to 950 °C for 1 hour to 24 hours.

[0013] In some embodiments, applying the current to the solution containing dissolved manganese includes applying a current density to the anode and cathode of the electrolytic cell of 10 amperes per square meter of electrode surface to 100 amperes per square meter of electrode surface.

[0014] In some embodiments, applying the current to the solution containing dissolved manganese includes applying a current density to the anode and cathode of the electrolytic cell of 27 amperes per square meter of electrode surface to 64.4 amperes per square meter of electrode surface.

[0015] According to an alternative embodiment (according to the invention), a method for producing a battery with a lithium manganese nickel oxide cathode is provided. The method comprises providing an anode for the battery, a separator for the battery, and an electrolyte solution for the battery. The method further comprises producing the lithium manganese nickel oxide cathode. The formation of the lithium manganese nickel oxide cathode comprises dissolving metallic manganese in acid to produce a solution containing dissolved manganese, arranging the solution containing dissolved manganese in an electrolytic cell with an anode and a cathode, and applying a current between the anode and cathode of the electrolytic cell. Applying the current causes a deposition layer of MnO₂ to form on the anode of the electrolytic cell.The formation of the lithium manganese nickel oxide cathode further comprises harvesting the formed MnO₂ deposit layer from the anode of the electrolytic cell, generating a manganese precursor by neutralizing the MnO₂ deposit layer and grinding the MnO₂ deposit layer to form an MnO₂ powder, and mixing the manganese precursor with a nickel precursor and a lithium precursor to produce a mixture. The formation of the lithium manganese nickel oxide cathode further comprises calcining the mixture to produce a lithium manganese nickel oxide powder and coating a current collector with the lithium manganese nickel oxide powder. The process further comprises arranging the separator and the electrolyte solution between the battery anode and the lithium manganese nickel oxide cathode to form the battery.

[0016] In some embodiments, the production of the manganese precursor also includes calcining the MnO2 powder under atmospheric air or oxygen gas to produce Mn2O3.

[0017] In some embodiments, the calcination of the MnO2 powder involves heating the MnO2 powder at a temperature of 700 °C to 950 °C for 1 hour to 24 hours.

[0018] In some embodiments, the manganese precursor contains alkali metal impurities and alkaline earth metal impurities of 10 parts by weight to 100 parts by weight, based on one million parts by weight of the manganese precursor.

[0019] In some embodiments, the manganese precursor contains particles with a diameter of at least 100 nanometers.

[0020] In some embodiments, the manganese precursor has a particle surface area of ​​0.5 square meters per gram to 5 square meters per gram.

[0021] In some embodiments, calcining the mixture involves heating the mixture to a temperature of 700 °C to 950 °C for 1 hour to 24 hours.

[0022] In some embodiments, applying the current to the solution containing dissolved manganese includes applying a current density to the anode and cathode of the electrolytic cell of 10 amperes per square meter of electrode surface to 100 amperes per square meter of electrode surface.

[0023] In some embodiments, a device is provided which contains a lithium manganese nickel oxide cathode formed by the method disclosed herein.

[0024] The above features and advantages, as well as further features and advantages of the present disclosure, are readily apparent from the following detailed description of the best variants for carrying out the disclosure in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 schematically shows an exemplary battery cell comprising an anode, a cathode, a separator and an electrolyte composition according to the present disclosure; Fig. 2 and Fig. Figure 3 schematically shows an industrial electrolytic cell for obtaining or harvesting MnO2 from a solution containing dissolved manganese according to the present disclosure; Fig. Figure 2 shows the solution containing dissolved manganese located between the anode and the cathode before current is applied to the anode and the cathode; Fig. Figure 3 schematically shows the industrial electrolytic cell after current has been applied to the solution containing dissolved manganese and a deposition layer of MnO2 has formed on the anode. Fig. 2 formed; Fig. 4 shows the anode of Fig. 3, wherein the deposition layer of MnO2 is made of Fig. 3 was removed from a surface of the anode, according to the present disclosure; Fig. Figure 5 schematically shows an exemplary device, e.g. a battery-powered electric vehicle (BEV), with a battery pack containing a plurality of batteries, according to the present disclosure; Fig. Figure 6 is a graph showing the effect of an electrolyte additive and lithium manganese nickel oxide (LNMO) purity on the maintenance of battery capacity for a plurality of batteries according to the present disclosure; Fig. Figure 7 is a graph showing the effect of an electrolyte additive and LNMO purity on the Coulomb efficiency for a plurality of batteries designed as single-layer pouch battery cells according to the present disclosure; and Fig. Figure 8 schematically shows a workflow of a disclosed process for producing a lithium manganese nickel oxide cathode and a battery containing the cathode, according to the present disclosure. DETAILED DESCRIPTION

[0025] The disclosed methods and devices use a high-purity manganese precursor as a starting material for the synthesis of high-voltage (4.7 V) LiNi. x Mn y O z (LMNO), which can be used as a cathode material, where x = 0.4 - 0.6, y = 1.45 - 1.55, z = 3.8 - 4.0. In one embodiment, the LNMO can be used as LiNi 0,5 Mn 1,5O4 are represented. In one embodiment, the high-purity manganese precursor comprises electrolytic manganese dioxide (EMD) or MnO2. In another embodiment, the high-purity manganese precursor comprises Mn2O3 (manganese(III) oxide).

[0026] One process for producing a high-purity manganese precursor involves the conversion of metallic manganese to manganese oxide. Manganese precursors produced by some processes can contain impurities such as alkali metals (e.g., sodium and potassium) and alkaline earth metals (e.g., calcium) in amounts of 200 parts per million (ppm) or more. The described process enables the production of a high-purity manganese precursor in which such impurities are present in amounts of 50 ppm to 100 ppm.

[0027] The high-purity manganese precursor can be produced in powder form. In a first step of producing the high-purity manganese precursor, metallic manganese is converted to manganese dioxide (MnO2). This conversion can involve dissolving metallic manganese in sulfuric or nitric acid to produce a solution containing dissolved manganese, maintaining a manganese concentration of 20 grams per liter to 100 grams per liter. In one embodiment, the manganese concentration can be approximately 47 grams per liter. The solution containing dissolved manganese can have a pH of 5.5 to 7.0. The solution containing dissolved manganese is passed through at least one industrial electrolytic cell and subjected to an electric current, maintaining a temperature of 93 °C to 99 °C and an anode current density of 10 amperes per square meter to 100 amperes per square meter.In one embodiment, the anode current density in the electrolytic cell can be maintained at 27 amperes per square meter up to 64.4 amperes per square meter. The industrial electrolytic cell is used to recover MnO₂ from the solution containing dissolved manganese and differs from the electrical cell produced using the disclosed LMNO cathode. As the solution containing dissolved manganese flows through the industrial electrolytic cell, MnO₂ is deposited on the anode. The deposited MnO₂ is collected at the anode. This collected MnO₂ is ground and neutralized with a basic solution, e.g., an ammonium hydroxide solution. After neutralization, the MnO₂ particles are ground to produce an MnO₂ powder or EMD powder. In one embodiment, this EMD powder can be used to produce LNMO cathodes.In another embodiment, where Mn₂O₃ powder is used to produce LNMO cathodes, the MnO₂ powder can be calcined at a temperature of 700 °C to 950 °C for 1 to 24 hours under atmospheric air or oxygen gas, resulting in the oxidation of the MnO₂ to Mn₂O₃. In another embodiment, the MnO₂ powder can be calcined at a temperature of 700 °C to 850 °C for 12 hours. The resulting manganese precursor can contain particles with a diameter greater than 100 nanometers, or with a diameter of 100 to 300 nanometers, or with a particle surface area of ​​0.5 to 5 square meters per gram.

[0028] The manganese precursor powder can be used to produce an LNMO cathode powder. Suitable molar ratios of EMD or Mn₂O₃, NiCO₃, and Li₂CO₃ are mixed and calcined at a temperature of 700 °C to 950 °C for 1 to 24 hours. This produces the LNMO cathode powder, which can be used to manufacture the cathode.

[0029] A cathode-shaped device manufactured according to the described method offers excellent cathode utilization, excellent coulombic efficiency, and excellent cycle life when used in a lithium-ion battery cell. The performance of the battery cells can be further improved by the use of an electrolyte additive.

[0030] A variety of electrolyte solutions can be used with the disclosed LNMO cathode. For example, a battery with an LNMO cathode can use either a carbonate-based or a boron-based electrolyte. Additionally, an electrolyte additive can be used to improve battery performance. In one example, fluorine-based electrolyte additives can be used. The disclosed method for producing LNMO cathodes and the LNMO cathodes with reduced impurities can operate more efficiently in the battery and interact with the electrolyte solution and / or electrolyte additives used, based on improved control over the chemical reactions taking place in the battery. The fewer impurities present in the cathode, the fewer unintended side reactions occur in the battery.

[0031] Referring to the drawings, in which the same reference numbers refer to the same features in the different views, shows Fig. Figure 1 schematically shows an exemplary battery cell 100 with an anode 110, a cathode 120, a separator 130, and an electrolyte solution 140. The battery 100 can be referred to as a battery cell or a battery system. In a charging cycle, the battery 100 enables the conversion of electrical energy into stored chemical energy, and in a discharging cycle, the battery 100 enables the conversion of stored chemical energy into electrical energy. The anode 110 contains a first current collector 112. The cathode 120 contains a second current collector 122. The first current collector 112 and the second current collector 122 can be made of copper, aluminum, or another non-reactive conductive material that can be used in the battery 100. The separator 130 can be operated in such a way that it separates the anode 110 from the cathode 120 and enables ion transfer through the separator 130.The electrolyte solution 140 is a liquid and / or a gel that provides a lithium ion conduction path between the anode 110 and the cathode 120.

[0032] The cathode 120 contains LNMO material that was produced and shaped on the cathode 120 according to the procedure described here.

[0033] The battery 100 and its components include the cathode 120, which is manufactured by the methods disclosed herein. Fig. 2 and Fig. Figure 3 schematically shows an industrial electrolytic cell 200 for the production of MnO2 from a solution 240 containing dissolved manganese. The electrolytic cell 200, an anode 210 and a cathode 220 used for the production of MnO2, differs from the battery 100, the anode 110 and the cathode 120. Fig. 1, which includes the cathode 120 formed from the recovered MnO2. The industrial electrolytic cell 200 is configured to receive current from an external power source to generate a current flow between the anode 210 and the cathode 220 within the industrial electrolytic cell 200. The solution 240 containing dissolved manganese is located in the industrial electrolytic cell 200 between the anode 210 and the cathode 220. The solution 240 containing dissolved manganese can be mixed with an electrolyte solution. The industrial electrolytic cell 200 also includes a separator 230, which is configured to allow ion transfer through the separator 230.

[0034] Fig. Figure 2 shows the solution containing dissolved manganese located between the anode and the cathode before current is applied to the anode and the cathode. Fig. Figure 3 schematically shows the industrial electrolytic cell 200 after current has been applied to the solution 240 with dissolved manganese and a deposition layer of MnO2 250 has formed on the anode 210.

[0035] Fig. Figure 4 shows anode 210, where the formed deposit layer of MnO2 250 has been removed from a surface of anode 210. Anode 210 can be obtained from the industrial electrolytic cell 200. Fig. 2 are removed to obtain or harvest the deposited layer of MnO2 250. The deposited layer of MnO2 250 can then be neutralized and milled as part of the disclosed process to generate EMD and / or further oxidize EMD to Mn2O3. The anode 210 can then be inserted or reinstalled in the industrial electrolytic cell 200 for repeated cycles of obtaining or harvesting the formed deposited layers of MnO2 250.

[0036] The Battery 100 can be used in a wide range of applications and powertrains. Fig. Figure 5 schematically shows an exemplary device 300, e.g., a battery-powered electric vehicle (BEV), with a battery pack 310 containing a plurality of batteries 100. The plurality of batteries 100 can be connected to one another in various combinations, e.g., by connecting some in parallel and some in series, to achieve the supply of electrical energy at a desired voltage. The battery pack 310 is electrically connected to a motor-generator unit 320, which serves to provide the vehicle 300 with motive power. The motor-generator unit 320 can include an output component 322, e.g., an output shaft, which provides mechanical energy that can be used to supply the motive power for the vehicle 300. A number of variations of the vehicle 300 are conceivable, and the disclosure is not intended to be limited to the examples given.

[0037] Fig. Figure 6 is a graph 400 showing the effect of an electrolyte additive and LNMO purity on battery capacity retention for a variety of batteries. The horizontal axis 402 denotes cycles, or a number of cycles, and represents the aging effects of a battery over time. The vertical axis 404 denotes the capacity retention of a battery as a percentage of the battery's original maximum capacity. Curves 410, 420, and 440 are shown, illustrating the capacity retention over time for four batteries with different configurations. Curve 410 shows the capacity retention over time for a base battery, or standard battery. Curve 420 shows the capacity retention over time for a battery with an electrolyte additive.Curve 440 shows the capacity retention over time for battery 100 with a high-voltage LNMO cathode (4.7 V) manufactured with a high-purity EMD powder. Curve 420 shows an improvement over curve 410. Curve 440 shows the improvement in capacity retention over time in the battery with the LNMO cathode compared to curves 410 and 420.

[0038] Fig. Figure 7 is a curve 500 showing the effect of an electrolyte additive and LNMO purity on the coulombic efficiency for a variety of batteries designed as single-layer pouch cells. The horizontal axis 502 denotes cycles or a number of cycles and represents the aging effects of a battery over time. The vertical axis 504 shows the coulombic efficiency of a battery as a percentage. Curves 510, 520, and 540 show the coulombic efficiency over time for four batteries of different configurations. Curve 510 shows the coulombic efficiency over time for a basic or standard battery. Curve 520 shows the coulombic efficiency over time for a battery with an electrolyte additive. Curve 540 shows the Coulomb efficiency over time for a battery with an LNMO high-voltage cathode (4.7 V) manufactured with a high-purity EMD powder.It can be seen that the battery with the LNMO cathode has an excellent efficiency compared to the other batteries.

[0039] Fig.Figure 8 schematically shows a workflow 600 of the disclosed process for producing the LMNO cathode. A process for producing a high-purity manganese precursor 605 is presented, comprising a step 602 in which metallic manganese is provided. In step 604, the metallic manganese is dissolved in acid to obtain a solution containing dissolved manganese. In step 606, the dissolved manganese is processed in an industrial electrolytic cell such that MnO2 is deposited on an anode of the industrial electrolytic cell. In step 608, the MnO2 deposited on the anode is harvested. In step 610, the recovered MnO2 is neutralized and milled. In an additional, optional step, the neutralized and milled MnO2 can be calcined to oxidize it to a Mn2O3 powder.The high-purity manganese precursor can also be described as a manganese precursor with alkali or alkaline earth metal impurities in amounts of 10 to 100 parts per million.

[0040] In step 612, a nickel precursor, such as nickel carbonate powder, is provided. In step 614, a lithium precursor, such as lithium carbonate powder, is provided. In step 616, the manganese precursor powder from step 610, the nickel precursor from step 612, and the lithium precursor from step 614 are mixed and calcined to produce LNMO for use in the fabrication of a cathode. In step 618, the LNMO is used to fabricate or create a cathode, for example, by forming the LNMO as a cathode electrode on a current collector. In step 620, the cathode is used to fabricate a battery that can be used in a variety of systems and devices. In the optional step 622, the cathode and / or a battery fabricated with the cathode can be tested, and the results evaluated.These evaluated test results can be fed back into the EMD production process 605 to optimize the process of producing high-purity manganese precursors 605. A number of variations of the described method and workflow 600 are conceivable, and the disclosure is not intended to be limited to the exemplary embodiments presented here.

[0041] A variety of alternative lithium precursors can be used in the described process. Examples include lithium hydroxide (LiOH), lithium hydroxide monohydrate (LiOH·H2O), lithium nitrate (LiNO3), lithium tert-butoxide (LiOC(CH3)3), lithium isopropoxide (LiCHO(CH3)2), and Lithia or lithium oxide (Li2O).

[0042] A variety of alternative nickel precursors can be used in the described process. Examples include nickel oxides, including various oxidation states of nickel oxides such as NiO and Ni2O3, nickel tetracarbonyl (Ni(CO)4), nickel nitrate (Ni(NO3)2), nickel sulfate (NiSO4), nickel isopropoxide (Ni(OC3H7)2), and metallic nickel.

[0043] The high-purity precursor further improved the testing of pouch cells compared to the conventional precursor. It is expected that a lack of or low levels of impurities in high-purity precursors will minimize side reactions between impurity particles and the electrolyte, as well as between impurity particles and lithium ions. This reduces the possibility of new compound formation. Furthermore, impurity particles can migrate to various parts of a pouch cell, including the separator and anode electrode, thereby triggering several failure mechanisms such as self-discharge and / or an increase in cell resistance. By reducing impurities in the cathode, existing impurities cannot migrate to the anode.

[0044] All of the above-mentioned conditions, such as interactions between electrolyte and impurities or between Li-ions and impurities, can worsen at elevated temperature, high voltage, or both.

[0045] Testing samples of the electrodes formed in the pouch cell allows for process adjustments to produce better resulting cathodes using the disclosed precursors. This enables an excellent contrast between LMNO precursors with an average amount of impurities and high-purity LMNO precursors.

Claims

[1] Method for producing a lithium manganese nickel oxide cathode using electrolytic manganese dioxide, the method comprising: Dissolving metallic manganese in acid to obtain a solution containing dissolved manganese; Arranging the solution with dissolved manganese in an electrolytic cell with an anode of the electrolytic cell and a cathode of the electrolytic cell; Applying a current between the anode of the electrolytic cell and the cathode of the electrolytic cell to the solution containing dissolved manganese, the application of the current forming a deposit layer of MnO2 on the anode of the electrolytic cell; Harvesting the formed MnO2 deposition layer from the anode of the electrolytic cell; Producing a manganese precursor by neutralizing the MnO2 deposition layer and grinding the MnO2 deposition layer to form an MnO2 powder; Mixing the manganese precursor with a nickel precursor and a lithium precursor to create a mixture; Calcining the mixture to produce a lithium manganese nickel oxide powder; and Coating a current collector with lithium manganese nickel oxide powder to form the lithium manganese nickel oxide cathode. [2] Method according to claim 1, wherein the production of the manganese precursor further comprises calcining the MnO2 powder under atmospheric air or oxygen gas to produce Mn2O3. [3] Method according to claim 2, wherein the calcining of the MnO2 powder comprises calcining the MnO2 powder at a temperature of 700 °C to 950 °C for 1 hour to 24 hours. [4] Method according to claim 2, wherein the calcining of the MnO2 powder comprises calcining the MnO2 powder at a temperature of 700 °C to 850 °C for 12 hours. [5] The method of claim 1, wherein the manganese precursor contains alkali metal impurities and alkaline earth metal impurities in an amount of 10 parts by weight to 100 parts by weight, based on one million parts by weight of the manganese precursor. [6] Method according to claim 1, wherein the manganese precursor contains particles with a diameter of at least 100 nanometers. [7] Method according to claim 1, wherein the manganese precursor contains particles with a diameter of 100 nanometers to 300 nanometers. [8] Method according to claim 1, wherein the manganese precursor has a particle surface area of ​​0.5 square meters per gram to 5 square meters per gram. [9] Method according to claim 1, wherein the calcining of the mixture comprises heating the mixture to a temperature of 700 °C to 950 °C for 1 hour to 24 hours. [10] Method for manufacturing a battery with a lithium manganese nickel oxide cathode, the method comprising: Providing an anode for the battery, a separator for the battery, and an electrolyte solution for the battery; Formation of the lithium manganese nickel oxide cathode, wherein the formation includes: Dissolving metallic manganese in acid to obtain a solution containing dissolved manganese; Arranging the solution with dissolved manganese in an electrolytic cell with an anode of the electrolytic cell and a cathode of the electrolytic cell; Applying a current between the anode of the electrolytic cell and the cathode of the electrolytic cell to the solution containing dissolved manganese, the application of the current forming a deposit layer of MnO2 on the anode of the electrolytic cell; Harvesting the formed MnO2 deposition layer from the anode of the electrolytic cell; Producing a manganese precursor by neutralizing the MnO2 deposition layer and grinding the MnO2 deposition layer to form an MnO2 powder; Mixing the manganese precursor with a nickel precursor and a lithium precursor to create a mixture; Calcining the mixture to produce a lithium manganese nickel oxide powder; and Coating a current collector with lithium manganese nickel oxide powder; and Arranging the separator and electrolyte solution between the anode for the battery and the lithium manganese nickel oxide cathode to form the battery.

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