WO2024066064A1 - 原位包覆氧化铜的氧化物复合正极材料、制备方法和用途 - Google Patents

原位包覆氧化铜的氧化物复合正极材料、制备方法和用途 Download PDF

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WO2024066064A1
WO2024066064A1 PCT/CN2022/138546 CN2022138546W WO2024066064A1 WO 2024066064 A1 WO2024066064 A1 WO 2024066064A1 CN 2022138546 W CN2022138546 W CN 2022138546W WO 2024066064 A1 WO2024066064 A1 WO 2024066064A1
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positive electrode
electrode material
copper
group
situ
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French (fr)
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胡勇胜
胡紫霖
容晓晖
陈立泉
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中国科学院物理研究所
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to the technical field of sodium ion battery materials, and in particular to an oxide composite positive electrode material coated with copper oxide in situ, a preparation method and use thereof.
  • the existing energy storage methods are divided into physical energy storage and chemical energy storage.
  • pumped storage is currently the most widely used and has the largest storage capacity, but pumped storage is limited by geographical location and has a long construction period.
  • Other physical energy storage such as compressed air energy storage and flywheel energy storage have not yet been scaled up.
  • Electrochemical energy storage refers to the storage or release of electricity through reversible chemical reactions. It has attracted widespread attention for its advantages such as high energy conversion efficiency and power density, long cycle life, short construction period, and low maintenance cost.
  • electrochemical energy storage mainly includes high-temperature sodium-sulfur batteries, flow batteries, lead-acid batteries and lithium-ion batteries.
  • the operating temperature of sodium-sulfur batteries Na-S batteries is 300°C, and metallic sodium and elemental sulfur are in a molten state. If the material is damaged at high temperature, it is easy to cause a fire in the battery module. Therefore, there are great safety issues and it has not been widely used.
  • Liquid flow batteries have low energy density and large volume. Compared with Ni-Cd batteries, lead-acid batteries have no memory effect and low cost. They currently account for the vast majority of the energy storage market and are widely used. However, their disadvantages are also quite obvious.
  • lead has a large environmental pollution
  • the battery has a low energy density, is heavy, has a large volume, and the maintenance cost will also increase.
  • the energy storage system needs to have the characteristics of low cost, green environmental protection, long life and high safety performance, among the many electrochemical energy storage materials, lithium-ion secondary batteries and sodium-ion secondary batteries have become more important technologies in energy storage technology.
  • lithium-ion batteries as electrochemical energy storage, have been widely used in daily life due to their advantages such as high energy density, high cycle stability, long cycle life, small size, light weight and no pollution.
  • sodium is an alkali metal element like lithium in the periodic table, they have similar physical and chemical properties.
  • Sodium-ion batteries and lithium-ion batteries have similar charging and discharging storage mechanisms. More importantly, sodium is abundant and widely distributed in nature, and has a significant price advantage.
  • aluminum foil can be used for both the positive and negative current collectors of sodium-ion batteries, while only copper can be used for the negative electrode of lithium-ion batteries. Obviously, copper is much more expensive than aluminum, so the raw material cost is low and easy to obtain.
  • Na x MO 2 represents 3d transition metal elements, which can contain one or more, such as Ti, V, Cr, Fe, Mn, Co, Ni, Cu, Nb, Ru, Mo, Zn, etc.
  • the basis of the battery is redox reaction, and the essence of the reaction is the change of valence, that is, the transfer and displacement of electrons.
  • the half-reaction of losing electrons is an oxidation reaction, and the valence of the cathode material increases; the half-reaction of gaining electrons is a reduction reaction, and the valence of the cathode material decreases.
  • the layered oxide cathode materials of sodium-ion batteries introduced above all have transition metal materials that can undergo redox reactions, and the variable valence transition metals in the initial state of the materials are in a lower valence state, but there are still many cases where the transition metal ions cannot completely change valence and the capacity cannot be fully utilized, and the air stability of these cathode materials is insufficient, resulting in poor consistency.
  • the purpose of the present invention is to provide an oxide composite positive electrode material in situ coated with copper oxide, a preparation method and use thereof, which utilizes the property that the solid solubility of copper is lower than that of other elements in the material preparation and synthesis process, and realizes one-step in situ coating of the positive electrode oxide material by adding an excessive amount of Cu element, so as to form a positive electrode material with the surface in situ coated with copper oxide, which can improve the air stability of the material and the electrical conductivity and sodium ion diffusion capacity of the material, so that the charge transfer impedance is lower, the first charge and discharge efficiency of the positive electrode material is higher, the cycle capacity is better, and the cycle life is longer.
  • an embodiment of the present invention provides an oxide composite positive electrode material in situ coated with copper oxide, the chemical formula of which is: ⁇ CuO-Na a Cu b Mn c M d O 2+ ⁇ ;
  • M is an element that is doped to replace the transition metal position, including one or more of the non-metallic elements of group IIIA, group IV, group VA, and group VIA, and one or more of the transition metal elements of the fourth period and the fifth period;
  • the space group of the layered oxide composite positive electrode material is P63/mmc or P63/mcm, and the corresponding structure is P2 phase; or the space group is The corresponding structure is O3 phase; or the space group is P63/mmc and Mixed, the corresponding structure is or P2/O3 mixed phase;
  • ⁇ CuO is a coating layer in situ generated on the surface of Na a Cu b Mn c M d O 2+ ⁇ by excessively added Cu element during the sintering process of preparing the positive electrode material, and ⁇ is the molar ratio of excess copper element in the precursor material; wherein 0.1% ⁇ 10%.
  • an embodiment of the present invention provides a method for preparing an oxide composite positive electrode material in situ coated with copper oxide, the method being a solid phase method, comprising:
  • the positive electrode material precursor is uniformly mixed by ball milling to obtain precursor powder;
  • the precursor powder is placed in a muffle furnace or a tube furnace and heat treated in an air or oxygen atmosphere at 600° C. to 1000° C. for 2 to 24 hours;
  • the powder obtained after the heat treatment is ground to obtain the in-situ copper oxide-coated oxide composite positive electrode material.
  • an embodiment of the present invention provides a method for preparing an oxide composite positive electrode material in situ coated with copper oxide, the method being a spray drying method, comprising:
  • the slurry is spray-dried to obtain a precursor powder
  • the precursor powder is placed in a muffle furnace or a tube furnace and heat treated in an air or oxygen atmosphere at 600° C. to 1000° C. for 2 to 24 hours;
  • the powder obtained after the heat treatment is ground to obtain the oxide composite positive electrode material with the surface in-situ coated with copper oxide.
  • an embodiment of the present invention provides a method for preparing an oxide composite positive electrode material in situ coated with copper oxide, the method being a combustion method, comprising:
  • Sodium nitrate with a stoichiometric amount of 100wt% to 110wt% of the required sodium, copper nitrate with a stoichiometric amount of 100.1wt% to 110wt% of the required copper, and nitrates of manganese and M with a stoichiometric amount are mixed to form a positive electrode material precursor; wherein M is an element for doping and replacing the transition metal position, including one or more of the non-metallic elements of group IIIA, group IV, group VA, and group VIA, and one or more of the transition metal elements of the fourth period and the fifth period;
  • the precursor powder is placed in a muffle furnace or a tube furnace and heat treated in an air or oxygen atmosphere at 600° C. to 1000° C. for 2 to 24 hours;
  • the powder obtained after the heat treatment is ground to obtain the oxide composite positive electrode material with surface in-situ coated copper oxide.
  • an embodiment of the present invention provides a method for preparing an oxide composite positive electrode material in situ coated with copper oxide, the method being a sol-gel method, comprising:
  • Sodium salt of the required sodium stoichiometric amount of 100wt% to 110wt%, copper nitrate or sulfate of the required copper stoichiometric amount of 100.1wt% to 110wt%, and nitrate or sulfate of the required manganese and M in the required stoichiometric amount are dissolved in water or ethanol in proportion to form a precursor solution;
  • the M is an element for doping and replacing the transition metal position, including one or more of the non-metallic elements of group IIIA, group IV, group VA, and group VIA, and one or more of the transition metal elements of the fourth period and the fifth period;
  • the sodium salt includes: one or more of sodium acetate, sodium nitrate, sodium carbonate or sodium sulfate;
  • the precursor solution is stirred at 50° C. to 100° C., and a chelating agent is added in an amount of 2 to 6 times the total molar amount of the transition metal, and evaporated to form a precursor gel;
  • the transition metal includes Cu and M;
  • the precursor gel is placed in a crucible and pre-fired for 2 hours in an air atmosphere at 200° C. to 500° C.;
  • the pre-calcined powder is then placed in a muffle furnace or a tube furnace and heat treated in an air or oxygen atmosphere at 600°C to 1000°C for 2 to 24 hours;
  • the material obtained after the heat treatment is ground to obtain the oxide composite positive electrode material with the surface in-situ coated with copper oxide.
  • an embodiment of the present invention provides a method for preparing an oxide composite positive electrode material in situ coated with copper oxide, the method being a coprecipitation method, comprising:
  • Copper nitrate of the required stoichiometric amount of copper 100.1wt% to 110wt% and nitrate of manganese and M of the required stoichiometric amount are dissolved in water in proportion and mixed to form a precursor solution;
  • M is an element for doping and replacing the transition metal position, including one or more of the non-metallic elements of group IIIA, group IV, group VA, and group VIA, and one or more of the transition metal elements of the fourth period and the fifth period;
  • the obtained precipitate is cleaned with deionized water, dried, and then uniformly mixed with sodium carbonate having a stoichiometric ratio of 100 wt% to 110 wt% of the required sodium to obtain a precursor;
  • the precursor is placed in a crucible or a porcelain boat, and heat treated in an air or oxygen atmosphere at 600° C. to 1000° C. for 2 to 24 hours;
  • the powder obtained after the heat treatment is ground to obtain the oxide composite positive electrode material with surface in-situ coated copper oxide.
  • an embodiment of the present invention provides a positive electrode plate for a sodium ion secondary battery, comprising: a current collector, a conductive additive coated on the current collector, a binder, and the in-situ copper oxide-coated oxide composite positive electrode material described in the first aspect above.
  • an embodiment of the present invention provides a sodium ion secondary battery comprising the positive electrode plate described in the seventh aspect.
  • an embodiment of the present invention provides a use of the sodium ion secondary battery described in the eighth aspect above, wherein the sodium ion secondary battery is used for large-scale energy storage equipment for solar power generation, wind power generation, smart grid peak regulation, distributed power stations, backup power supplies or communication base stations.
  • the in-situ copper oxide-coated oxide composite positive electrode material provided by the embodiment of the present invention utilizes the lower solid solubility of copper compared to other elements to form an in-situ generated copper oxide coating layer enriched on the surface.
  • the presence of the coating layer greatly reduces the residual alkali generated on the surface of the material due to contact with the air, significantly improves the stability in the air, and has higher electrical conductivity and sodium ion diffusion capacity of the material, lower charge transfer impedance, higher initial charge and discharge efficiency, better cycle capacity, and especially longer cycle life.
  • FIG1 is a schematic diagram of a process for preparing an oxide composite positive electrode material in situ coated with copper oxide by sintering provided in an embodiment of the present invention
  • FIG2 is an X-ray diffraction (XRD) spectrum of an oxide composite positive electrode material in situ coated with copper oxide according to different embodiments provided in an embodiment of the present invention
  • FIG3 is a charge and discharge curve diagram of the sodium ion battery provided in Example 1 of the present invention at 2.5-4.2V;
  • FIG4 is a comparison diagram of sodium ion battery cycle curves provided in Example 1 of the present invention.
  • FIG5 is an XRD spectrum of the in-situ copper oxide-coated oxide composite positive electrode material provided in Example 1 of the present invention before and after being immersed in deionized water for 48 hours;
  • Example 6 is a comparison diagram of the charge and discharge curves of a sodium ion battery at 2.5-4.2V prepared from the oxide composite positive electrode material in situ coated with copper oxide provided in Example 1 of the present invention before and after being immersed in deionized water for 48 hours;
  • FIG. 7 is an XRD spectrum of the unsurface-coated oxide positive electrode material provided in Example 1 of the present invention before and after being immersed in deionized water for 48 hours.
  • the embodiment of the present invention provides an oxide composite positive electrode material coated with copper oxide in situ, and its general chemical formula is: ⁇ CuO-Na a Cu b Mn c M d O 2+ ⁇ ;
  • M is an element that dopes and replaces the transition metal position, including one or more of the non-metallic elements of group IIIA, group IV, group VA, and group VIA, and one or more of the transition metal elements of the fourth period and the fifth period;
  • the space group of the layered oxide composite positive electrode material is P63/mmc or P63/mcm, and the corresponding structure is P2 phase; or the space group is The corresponding structure is O3 phase; or the space group is P63/mmc and Mixed, the corresponding structure is or P2/O3 mixed phase;
  • ⁇ CuO is a coating layer in situ generated on the surface of Na a Cu b Mn c M d O 2+ ⁇ by excessively added Cu element during the sintering process of preparing the positive electrode material, and ⁇ is the molar ratio of excess copper element in the precursor material; wherein 0.1% ⁇ 10%, preferably 2% ⁇ 6%.
  • the solid solubility of copper is lower than that of other elements.
  • the excessive copper added in the precursor cannot be dissolved into the bulk phase of the material during the sintering process, and is enriched on the surface of the particles in the form of copper oxide. It can evenly and completely wrap the layered oxide positive electrode, and the copper oxide coating layer is generated in situ.
  • the process schematic diagram is shown in Figure 1.
  • the oxide composite positive electrode material with copper oxide in-situ coated on the surface has the characteristics of air stability, high capacity, and high cycle stability. This material can remain structurally stable after being placed in 45% RH-60% RH air for more than 48 hours.
  • the copper-based oxide material in situ coated with copper oxide of the present invention can be used in a positive electrode sheet, and is prepared by mixing the copper-based oxide material in situ coated with copper oxide with a conductive additive and a binder and then coating the mixture on a current collector.
  • the conductive additive, binder and current collector used can all be conductive additives, binders and current collectors commonly used in sodium ion battery positive electrodes in the prior art, and are not particularly limited here.
  • the oxide composite positive electrode material that can be in-situ coated with copper oxide proposed by the present invention is used for large-scale energy storage equipment such as solar power generation, wind power generation, smart grid peak regulation, distributed power stations, backup power supplies or communication base stations.
  • the in-situ copper oxide-coated oxide composite positive electrode material of the present invention can be prepared by the following methods.
  • a solid phase method is used for preparation, and the main steps include:
  • spray drying is used for preparation, and the main steps include:
  • M is as defined above.
  • the combustion method is used for preparation, and the main steps include:
  • the sol-gel method is used for preparation, and the main steps include:
  • sodium salt includes: one or more of sodium acetate, sodium nitrate, sodium carbonate or sodium sulfate.
  • a coprecipitation method is used for preparation, and the main steps include:
  • the following uses a number of specific examples to illustrate the specific process of preparing the in-situ copper oxide-coated oxide composite positive electrode material using several methods provided in the above embodiments of the present invention, as well as the method and battery characteristics of applying it to sodium ion secondary batteries.
  • a solid phase method is used to prepare an oxide composite positive electrode material in situ coated with copper oxide.
  • the required stoichiometric Na 2 CO 3 (analytical grade) and MnO 2 (analytical grade) were mixed with the required copper stoichiometric 101wt% CuO (analytical grade) and 100wt% CuO (analytical grade) (comparative example) in a stoichiometric ratio, respectively, and ball-milled in an agate mortar for half an hour to obtain two positive electrode material precursors, one with excess CuO and the other with no excess CuO (as a comparative example);
  • the two cathode material precursors were transferred into Al 2 O 3 crucibles respectively and treated in an oxygen atmosphere in a muffle furnace at 900°C for 15 hours to obtain black powder layered oxide materials Na 0.67 Cu 0.33 Mn 0.6 O 2 (CuO was not obtained in excess) and 1% CuO-Na 0.67 Cu 0.33 Mn 0.6 O 2 (CuO was obtained in excess), and their XRD patterns are shown in Figure 2.
  • the crystal structures of Na 0.67 Cu 0.33 Mn 0.6 O 2 and 1% CuO-Na 0.67 Cu 0.33 Mn 0.6 O 2 are both P2 phase layered oxides, and their space group is P63/mmc.
  • the above-prepared in-situ copper oxide-coated oxide composite positive electrode material is used as the active material of the battery positive electrode material for the preparation of a sodium ion battery:
  • the prepared 1% CuO-Na 0.67 Cu 0.33 Mn 0.6 O 2 powder is mixed with acetylene black and binder polyvinylidene fluoride (PVDF) in a mass ratio of 80:10:10, and an appropriate amount of N-methylpyrrolidone (NMP) solution is added, and the slurry is ground in a dry environment at room temperature to form a slurry, and then the slurry is evenly coated on the current collector aluminum foil, and after drying under an infrared lamp, it is cut into (8 ⁇ 8) mm 2 pole pieces. The pole pieces are dried at 110°C for 10 hours under vacuum conditions and then transferred to a glove box for standby use.
  • PVDF acetylene black and binder polyvinylidene fluoride
  • NMP N-methylpyrrolidone
  • the assembly of the simulated battery was carried out in a glove box with an Ar atmosphere, using metallic sodium as the counter electrode and 1 mol/L NaClO 4 / diethyl carbonate (DEC) solution as the electrolyte to assemble a CR2032 button cell.
  • the constant current charge and discharge mode was used to perform charge and discharge tests at C/10 and 1.0C current density. Under the conditions of a discharge cut-off voltage of 2.5V and a charge cut-off voltage of 4.2V, the charge and discharge test results at 2.5-4.2V are shown in Figure 3, and the battery cycle curve is shown in Figure 4.
  • Figures 5 and 6 are the XRD patterns before and after the comparison. It can be seen that the XRD of the oxide composite positive electrode material with copper oxide in situ coated on the surface did not change significantly before and after soaking in deionized water for 48 hours, while the XRD of the oxide positive electrode material without copper oxide changed significantly before and after soaking in deionized water for 48 hours, indicating that the oxide composite positive electrode material with copper oxide in situ coated on the surface prepared by the present invention greatly improves the stability of the material to water.
  • the layered oxide material obtained before and after soaking in deionized water is used as the active material of the battery positive electrode material for the preparation of sodium ion batteries, and an electrochemical charge and discharge test is performed.
  • the preparation process and test method are the same as in Example 1, and the test voltage range is 2.5 to 4.2 V.
  • FIG7 is the charge and discharge test result. From the charge and discharge curve and the reversible specific capacity, the presence of the coating layer greatly improves the stability of the material to water, further proving that the presence of the coating layer can improve the air stability of the material.
  • a solid phase method is used to prepare an oxide composite positive electrode material in situ coated with copper oxide.
  • the required stoichiometric Na 2 CO 3 (analytical grade), MnO 2 (analytical grade), Fe 2 O 3 (analytical grade) and the required stoichiometric CuO (analytical grade) of 102 wt% were mixed in a stoichiometric ratio; the mixture was ball-milled in an agate mortar for half an hour to obtain a precursor;
  • the precursor was transferred into an Al 2 O 3 crucible and treated in an oxygen atmosphere in a muffle furnace at 900° C. for 15 hours to obtain a black powder layered oxide material 2% CuO—Na 0.67 Cu 0.22 Mn 0.67 Fe 0.11 O 2 . See FIG2 for its XRD spectrum.
  • the crystal structure of 2%CuO-Na 0.67 Cu 0.22 Mn 0.67 Fe 0.11 O 2 is a P2 phase layered oxide. Its space group is P63/mmc.
  • the above-prepared in-situ copper oxide-coated oxide composite positive electrode material was used as the active material of the battery positive electrode material for the preparation of a sodium ion battery, and an electrochemical charge and discharge test was performed.
  • the preparation process and test method were the same as in Example 1.
  • the test voltage range was 2.5 to 4.2 V, and the reversible specific capacity of the material was shown in Table 1.
  • a solid phase method is used to prepare an oxide composite positive electrode material in situ coated with copper oxide.
  • the required stoichiometric Na 2 CO 3 (analytical grade), Li 2 CO 3 (analytical grade), NiO (analytical grade), MnO 2 (analytical grade) and the required copper stoichiometric 104 wt % CuO (analytical grade) were mixed in a required stoichiometric ratio; ball milled in an agate mortar for half an hour to obtain a precursor;
  • the precursor was transferred into an Al 2 O 3 crucible and treated in an oxygen atmosphere in a muffle furnace at 900° C. for 15 hours to obtain a black powder layered oxide material 4% CuO-Na 0.76 Li 0.03 Ni 0.15 Cu 0.18 Mn 0.64 O 2 , whose XRD spectrum is shown in FIG2 .
  • the crystal structure of 4%CuO-Na 0.76 Li 0.03 Ni 0.15 Cu 0.18 Mn 0.64 O 2 is a P2 phase layered oxide. Its space group is P63/mmc.
  • the above-prepared in-situ copper oxide-coated oxide composite positive electrode material was used as the active material of the battery positive electrode material for the preparation of a sodium ion battery, and an electrochemical charge and discharge test was performed.
  • the preparation process and test method were the same as in Example 1.
  • the test voltage range was 2.5 to 4.2 V, and the reversible specific capacity of the material was shown in Table 1.
  • a solid phase method is used to prepare an oxide composite positive electrode material in situ coated with copper oxide.
  • the required stoichiometric Na 2 CO 3 (analytical grade), MnO 2 (analytical grade), Fe 2 O 3 (analytical grade), ZnO (analytical grade) and the required copper stoichiometric 100.5 wt% CuO (analytical grade) were mixed in a required stoichiometric ratio; the mixture was ball-milled in an agate mortar for half an hour to obtain a precursor;
  • the precursor was transferred into an Al 2 O 3 crucible and treated in an oxygen atmosphere in a muffle furnace at 900° C. for 15 hours to obtain a black powder layered oxide material 0.5% CuO-Na 0.8 Cu 0.2 Mn 0.63 Fe 0.12 Zn 0.05 O 2 , whose XRD spectrum is shown in FIG2 .
  • the crystal structure of 0.5% CuO-Na 0.8 Cu 0.2 Mn 0.63 Fe 0.12 Zn 0.05 O 2 is a P2/O3 mixed phase oxide. Its space group is P63/mmc and Mix.
  • the above-prepared in-situ copper oxide-coated oxide composite positive electrode material was used as the active material of the battery positive electrode material for the preparation of a sodium ion battery, and an electrochemical charge and discharge test was performed.
  • the preparation process and test method were the same as in Example 1.
  • the test voltage range was 2.5 to 4.2 V, and the reversible specific capacity of the material was shown in Table 1.
  • a solid phase method is used to prepare an oxide composite positive electrode material in situ coated with copper oxide.
  • the precursor was transferred into an Al 2 O 3 crucible and treated in an oxygen atmosphere in a muffle furnace at 900° C. for 15 hours to obtain a black powder layered oxide material 7% CuO-Na 1.0 Cu 0.5 Mn 0.3 Ti 0.2 O 2 , whose XRD spectrum is shown in FIG2 .
  • the crystal structure of 7% CuO-Na 1.0 Cu 0.5 Mn 0.3 Ti 0.2 O 2 is an oxide with an O3 structure. Its space group is
  • the above-prepared in-situ copper oxide-coated oxide composite positive electrode material was used as the active material of the battery positive electrode material for the preparation of sodium ion batteries, and electrochemical charge and discharge tests were performed.
  • the preparation process and test method are the same as
  • Example 1 The test voltage range is 2.5 to 4.2 V, and the reversible specific capacity of the material is shown in Table 1.
  • the oxide composite positive electrode material prepared by the present invention and coated with copper oxide in situ has better performance in reversible specific capacity and 1.0C cycle capacity retention rate than the positive electrode material without copper oxide coating.

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Abstract

一种原位包覆氧化铜的氧化物复合正极材料、其制备方法和用途。原位包覆氧化铜的氧化物复合正极材料的化学通式为：γCuO-Na aCu bMn cM dO 2+β；Na aCu bMn cM dO 2+β中，Cu、Mn、M共同占据晶体结构中的过渡金属位；M为对过渡金属位进行掺杂取代的元素；γCuO为烧结制备原位包覆氧化铜的氧化物复合正极材料的过程中，过量添加的Cu元素在Na aCu bMn cM dO 2+β表面原位生成的包覆层。

Description

原位包覆氧化铜的氧化物复合正极材料、制备方法和用途
本申请要求于2022年09月27日提交中国专利局、申请号为202211183418.1、发明名称为“原位包覆氧化铜的氧化物复合正极材料、制备方法和用途”的中国专利申请的优先权。
技术领域
本发明涉及钠离子电池材料技术领域，尤其涉及原位包覆氧化铜的氧化物复合正极材料、制备方法和用途。
背景技术
随着社会的发展与进步，人类对能源的需求量越来越大，但煤、石油、天然气等传统化石能源由于资源日渐枯竭，再加上其造成的城市环境污染和温室效应问题日益严峻，其应用逐渐受到多方面限制，因此可持续清洁能源的开发一直是各国关注的方向。但是将风能、太阳能和潮汐能等转换成电能的过程中，这些可再生能源受自然条件的限制较大，并具有明显的时间不连续性、空间分布不均匀性等特点，这导致它们提供的电力可控性和稳定性较差，不能直接输入电网使用。因此，只有配套高性能的大规模储能系统，以此解决发电与用电的时差矛盾、调节电能品质，才能确保电力系统可靠供电。当前我国能源的可持续发展对大规模储能技术需求较为迫切，同时这也是世界各国的研究热点。
目前已有的储能方式分为物理储能和化学储能。物理储能中抽水蓄能是目前使用最多，储能量最大的，但是抽水蓄能受到地理位置的限制，且建设工期较长，其它物理储能如压缩空气储能、飞轮储能等都还未成规模。电化学储能是指通过发生可逆的化学反应来储存或释放电量，它以其高能量转换效率和功率密度、循环寿命长、建设周期短、维护成本低等优势受到人们的普遍关注。
现今阶段，电化学储能主要包括高温钠硫电池、液流电池、铅酸电池和锂离子电池等这几大类。钠硫电池Na-S电池的工作温度为300℃，金属钠和单质硫处于熔融状态，如果高温下材料破损容易在电池模块中引起火灾，因此安全问题很大，未能大规模应用。液流电池能量密度较低、体积较大。铅酸电池相对于Ni-Cd电池无记忆效应、成本低，目前一直占储能市场的绝大部分比例，应用广泛。但是其缺点也比较明显， 例如铅对环境污染大、电池能量密度低、质量重、体积较大，维护费用也会增加。由于储能系统需要具有成本低廉、绿色环保、寿命长和安全性能高等特点，在众多的电化学储能材料中，锂离子二次电池和钠离子二次电池成为储能技术中比较重要的技术。
目前作为电化学储能的锂离子电池以高能量密度、高循环稳定性、长循环寿命、体积小重量轻及无污染等优点，在日常生活中得到了广泛应用。考虑到钠在元素周期表中与锂同属于碱金属元素，因此具有相似的物理化学性质。钠离子电池和锂离子电池有相似的充放电储存机制，更重要的是钠在自然界中储量丰富且分布广泛，还有很显著的价格优势。除了钠离子价格低外，钠离子电池的正负极集流体均可以使用铝箔，而锂离子电池负极只能用铜，显然铜比铝贵的多，因此原材料成本低廉且容易获得，这些优势使得钠离子电池越来越受到世界范围的广泛关注。
但目前钠离子电池还处于研究阶段，还没有商业化的钠离子电池正极材料，现在研究者对于钠离子电池的研究主要集中在层状结构的氧化物正极材料Na xMO 2(M代表3d过渡金属元素中，可包含一种或者多种，如Ti、V、Cr、Fe、Mn、Co、Ni、Cu、Nb、Ru、Mo、Zn等)。电池的基础是氧化还原反应，反应的本质是化合价有变化，即电子有转移和偏移。失电子的半反应是氧化反应，正极材料的化合价升高；得电子的半反应是还原反应，正极材料中化合价降低。而以上介绍的钠离子电池层状氧化物正极材料中均具有可以发生氧化还原反应的过渡金属材料，且材料初始状态的可变价过渡金属处于较低的价态，但是过渡金属离子无法完全变价、容量无法完全发挥的情况仍然有很多，且这些正极材料的空气稳定性不足导致一致性不好。
发明内容
本发明的目的是提供一种原位包覆氧化铜的氧化物复合正极材料、制备方法和用途，利用了材料制备合成过程铜的固溶度相较于其他元素的固溶度较低的特性，通过过量的Cu元素的加入，实现了正极氧化物材料的一步原位包覆，形成表面原位包覆氧化铜的正极材料，能够提高材料的空气稳定性和材料的电导率和钠离子扩散能力，从而电荷转移阻抗更低，正极材料的首次充放电效率更高，循环能力更佳，循环寿命更长。
为此，第一方面，本发明实施例提供了一种原位包覆氧化铜的氧化物复合正极材料的化学通式为：γCuO-Na aCu bMn cM dO 2+β；
所述氧化物复合正极材料中，Cu、Mn、M共同占据晶体结构中的过渡金属离子位置； M为对过渡金属位进行掺杂取代的元素，包括ⅢA族、Ⅳ主族、VA族元素，以及VIA族的非金属元素中的一种或多种以及第四周期和第五周期的过渡金属元素中的一种或多种；
所述层状氧化物复合正极材料的空间群为P63/mmc或P63/mcm，对应结构为P2相；或空间群为
Figure PCTCN2022138546-appb-000001
对应结构为O3相；或空间群为P63/mmc与
Figure PCTCN2022138546-appb-000002
混和，对应结构为或P2/O3混和相；
所述a，b，c，d，2+β分别为对应元素所占的摩尔百分比，化学通式中各组分满足电荷守恒和化学计量守恒；其中，b+c+d＝1，且a+2b+4c+md＝2(2+β)；0.66≤a≤1；0＜b≤0.5；0＜c≤0.8；0＜d≤0.65；-0.05≤β≤0.05；m为M的化合价态；
γCuO为烧结制备正极材料过程中，过量添加的Cu元素在Na aCu bMn cM dO 2+β表面原位生成的包覆层，γ为前驱体材料中铜元素过量的摩尔比；其中，0.1％≤γ≤10％。
优选的，2％≤γ≤6％。
第二方面，本发明实施例提供了一种原位包覆氧化铜的氧化物复合正极材料的制备方法，所述方法为固相法，包括：
将所需钠的化学计量100wt％～108wt％的碳酸钠、所需铜的化学计量100.1wt％～110wt％的铜的氧化物、所需化学计量的锰和M的氧化物或碳酸盐混合成正极材料前驱体；所述M为对过渡金属位进行掺杂取代的元素，包括ⅢA族、Ⅳ主族、VA族元素，以及VIA族的非金属元素中的一种或多种以及第四周期和第五周期的过渡金属元素中的一种或多种；
采用球磨的方式将所述正极材料前驱体均匀混合得到前驱体粉末；
将所述前驱体粉末置于马弗炉或管式炉内，在600℃～1000℃的空气或氧气气氛中热处理2～24小时；
将热处理后所得粉末进行研磨，得到所述原位包覆氧化铜的氧化物复合正极材料。
第三方面，本发明实施例提供了一种原位包覆氧化铜的氧化物复合正极材料的制备方法，所述方法为喷雾干燥法，包括：
将所需钠的化学计量100wt％～110wt％的碳酸钠或硝酸钠、所需铜的化学计量100.1wt％～110wt％的铜的硝酸盐、所需化学计量的锰的硝酸盐和M的氧化物或碳酸混合成正极材料前驱体；所述M为对过渡金属位进行掺杂取代的元素，包括ⅢA族、Ⅳ主 族、VA族元素，以及VIA族的非金属元素中的一种或多种以及第四周期和第五周期的过渡金属元素中的一种或多种；
将所述正极材料前驱体加乙醇或水后搅拌均匀形成浆料；
对所述浆料进行喷雾干燥后得到前驱体粉末；
将所述前驱体粉末置于马弗炉或管式炉内，在600℃～1000℃的空气或氧气气氛中热处理2～24小时；
将热处理后所得粉末进行研磨，得到所述表面原位包覆氧化铜的氧化物复合正极材料。
第四方面，本发明实施例提供了一种原位包覆氧化铜的氧化物复合正极材料的制备方法，所述方法为燃烧法，包括：
将所需钠的化学计量100wt％～110wt％的硝酸钠、所需铜的化学计量100.1wt％～110wt％的铜的硝酸盐、所需化学计量的锰和M的硝酸盐混合成正极材料前驱体；所述M为对过渡金属位进行掺杂取代的元素，包括ⅢA族、Ⅳ主族、VA族元素，以及VIA族的非金属元素中的一种或多种以及第四周期和第五周期的过渡金属元素中的一种或多种；
将所述正极材料前驱体加乙酰丙酮搅拌均匀形成浆料；
对所述浆料进行干燥后得到前驱体粉末；
将所述前驱体粉末置于马弗炉或管式炉内，在600℃～1000℃的空气或氧气气氛中热处理2～24小时；
将热处理后所得粉末进行研磨，得到所述具有表面原位包覆氧化铜的氧化物复合正极材料。
第五方面，本发明实施例提供了一种原位包覆氧化铜的氧化物复合正极材料的制备方法，所述方法为溶胶-凝胶法，包括：
将所需钠的化学计量100wt％～110wt％的钠盐，所需铜的化学计量100.1wt％～110wt％的铜的硝酸盐或硫酸盐，所需化学计量的锰和M的硝酸盐或硫酸盐按比例溶于水或者溶于乙醇，混合成前驱体溶液；所述M为对过渡金属位进行掺杂取代的元素，包括ⅢA族、Ⅳ主族、VA族元素，以及VIA族的非金属元素中的一种或多种以及第四周期和第五周期的过渡金属元素中的一种或多种；所述钠盐包括：乙酸钠、硝酸钠、碳酸钠或 硫酸钠中的一种或几种；
对所述前驱体溶液在在50℃～100℃下搅拌，并且加入过渡金属的摩尔总量2-6倍的螯合剂，蒸干形成前驱体凝胶；过渡金属包括Cu与M；
将所述前驱体凝胶置于坩埚中，在200℃～500℃的空气气氛下，预烧2个小时；
再将预烧所得粉末置于马弗炉或管式炉内，在600℃～1000℃的空气或氧气气氛中热处理2～24小时；
将热处理后所得材料进行研磨，得到所述表面原位包覆氧化铜的氧化物复合正极材料。
第六方面，本发明实施例提供了一种原位包覆氧化铜的氧化物复合正极材料的制备方法，所述方法为共沉淀法，包括：
将所需铜的化学计量100.1wt％～110wt％的铜的硝酸盐，以及所需化学计量的锰和M的硝酸盐按比例溶于水混合成前驱体溶液；所述M为对过渡金属位进行掺杂取代的元素，包括ⅢA族、Ⅳ主族、VA族元素，以及VIA族的非金属元素中的一种或多种以及第四周期和第五周期的过渡金属元素中的一种或多种；
用蠕动泵将所述前驱体溶液滴加在pH在7-14之间的氨水溶液中，生成沉淀物；
将得到的沉淀物用去离子水清洗干净，烘干后将所述沉淀物与所需钠的化学计量100wt％～110wt％的碳酸钠按照化学计量比均匀混合得到前驱物；
将所述前驱物置于坩埚或瓷舟中，在600℃～1000℃的空气或氧气气氛中热处理2～24小时；
将热处理后所得粉末进行研磨，得到所述具有表面原位包覆氧化铜的氧化物复合正极材料。
第七方面，本发明实施例提供了一种钠离子二次电池的正极极片，包括：集流体、涂覆于所述集流体之上的导电添加剂、粘结剂和上述第一方面所述的原位包覆氧化铜的氧化物复合正极材料。
第八方面，本发明实施例提供了一种包括上述第七方面所述的正极极片的钠离子二次电池。
第九方面，本发明实施例提供了一种上述第八方面所述的钠离子二次电池的用途，所述钠离子二次电池用于太阳能发电、风力发电、智能电网调峰、分布电站、后备电 源或通信基站的大规模储能设备。
本发明实施例提供的原位包覆氧化铜的氧化物复合正极材料，利用铜的固溶度相较于其他元素的固溶度较低，从而形成氧化铜在表面富集，原位生成的氧化铜包覆层，包覆层的存在使得材料表面由于与空气接触而产生的残碱大幅减少，空气中稳定性显著提升，材料的电导率、钠离子扩散能力更高，电荷转移阻抗更低，首次充放电效率更高，循环能力更佳，尤其循环寿命更长。
附图说明
图1为本发明实施例提供的烧结制备原位包覆氧化铜的氧化物复合正极材料过程中示意图；
图2为本发明实施例提供的不同实施例的原位包覆氧化铜的氧化物复合正极材料的X射线衍射(XRD)图谱；
图3为本发明实施例1提供的钠离子电池在2.5-4.2V充放电曲线图；
图4为本发明实施例1提供的钠离子电池循环曲线对比图；
图5为本发明实施例1提供的原位包覆氧化铜的氧化物复合正极材料在去离子水中浸泡48小时前后的XRD图谱；
图6为本发明实施例1提供的原位包覆氧化铜的氧化物复合正极材料在去离子水中浸泡48小时前后的材料制备的钠离子电池在2.5-4.2V充放电曲线对比图；
图7为本发明实施例1提供的未表面包覆的氧化物正极材料在去离子水中浸泡48小时前后的XRD图谱。
具体实施方式
下面通过附图和实施例，对本发明的技术方案做进一步的详细描述。
下面通过附图和实施例，对本发明的技术方案做进一步的详细描述。
本发明实施例提供了一种原位包覆氧化铜的氧化物复合正极材料，其化学通式为：γCuO-Na aCu bMn cM dO 2+β；
氧化物复合正极材料中，Cu、Mn、M共同占据晶体结构中的过渡金属离子位置；M为对过渡金属位进行掺杂取代的元素，包括ⅢA族、Ⅳ主族、VA族元素，以及VIA族的非金属元素中的一种或多种以及第四周期和第五周期的过渡金属元素中的一种或多种；
a，b，c，d，2+β分别为对应元素所占的摩尔百分比，化学通式中各组分满足电 荷守恒和化学计量守恒；其中，b+c+d＝1，且a+2b+4c+md＝2(2+β)；0.66≤a≤1；0＜b≤0.5；0＜c≤0.8；0＜d≤0.65；-0.05≤β≤0.05；m为M的化合价态；
层状氧化物复合正极材料的空间群为P63/mmc或P63/mcm，对应结构为P2相；或空间群为
Figure PCTCN2022138546-appb-000003
对应结构为O3相；或空间群为P63/mmc与
Figure PCTCN2022138546-appb-000004
混和，对应结构为或P2/O3混和相；
γCuO为烧结制备正极材料过程中，过量添加的Cu元素在Na aCu bMn cM dO 2+β表面原位生成的包覆层，γ为前驱体材料中铜元素过量的摩尔比；其中，0.1％≤γ≤10％，优选为2％≤γ≤6％。
在烧结制备铜基氧化物材料的过程中，利用铜的固溶度相较于其他元素的固溶度较低，前驱体中过量添加的铜在烧结过程中无法固溶进材料体相中去，以氧化铜的形式在颗粒表面富集，能够均匀、完整地包裹着层状氧化物正极，原位生成的氧化铜包覆层，过程示意图如图1所示。
由于致密、均匀的氧化铜包覆层的存在，使得材料表面由于与空气接触而产生的残碱大幅减少，空气中稳定性显著提升，材料的电导率、钠离子扩散能力更高，电荷转移阻抗更低，首次充放电效率更高，循环能力更佳，因而使得表面原位包覆氧化铜的氧化物复合正极材料具有空气稳定、高容量、高循环稳定性的特性，这种材料可以在45％RH-60％RH空气中放置48小时以上仍然保持结构稳定。
本发明的原位包覆氧化铜的铜基氧化物材料，可以用于正极极片中，通过将上述原位包覆氧化铜的铜基氧化物材料与导电添加剂和粘结剂混合后涂覆于集流体之上，制备得到。所用导电添加剂、粘结剂和集流体均可采用现有技术中钠离子电池正极常用的导电添加剂、粘结剂和集流体，在此不作特殊限定。
在装载有上述正极极片半电池测试中发现，该材料不但具有较高的质量比容量和比能量，比容量是普通钠离子电池正极材料的1.5到2倍，且循环寿命较好，具有很大实用价值。本发明提出的可以原位包覆氧化铜的氧化物复合正极材料用于太阳能发电、风力发电、智能电网调峰、分布电站、后备电源或通信基站的大规模储能设备。
本发明的原位包覆氧化铜的氧化物复合正极材料，可以通过如下几种方法制备得到。
在第一种方法中，采用固相法进行制备，主要步骤包括：
S1，将所需钠的化学计量100wt％～108wt％的碳酸钠、所需铜的化学计量100.1wt％～110wt％的铜的氧化物、所需化学计量的锰和M的氧化物或碳酸盐混合成正极 材料前驱体；其中，M如上限定。
S2，采用球磨的方式将正极材料前驱体均匀混合得到前驱体粉末；
S3，将前驱体粉末置于马弗炉或管式炉内，在600℃～1000℃的空气或氧气气氛中热处理2～24小时；
S4，将热处理后所得粉末进行研磨，得到原位包覆氧化铜的氧化物复合正极材料。
在第二种方法中，采用喷雾干燥法进行制备，主要步骤包括：
S1，将所需钠的化学计量100wt％～110wt％的碳酸钠或硝酸钠、所需铜的化学计量100.1wt％～110wt％的铜的硝酸盐、所需化学计量的锰的硝酸盐和M的氧化物或碳酸混合成正极材料前驱体；
其中，M如上限定。
S2，将正极材料前驱体加乙醇或水后搅拌均匀形成浆料；
S3，对浆料进行喷雾干燥后得到前驱体粉末；
S4，将前驱体粉末置于马弗炉或管式炉内，在600℃～1000℃的空气或氧气气氛中热处理2～24小时；
S5，将热处理后所得粉末进行研磨，得到表面原位包覆氧化铜的氧化物复合正极材料。
在第三种方法中，采用燃烧法进行制备，主要步骤包括：
S1，将所需钠的化学计量100wt％～110wt％的硝酸钠、所需铜的化学计量100.1wt％～110wt％的铜的硝酸盐、所需化学计量的锰和M的硝酸盐混合成正极材料前驱体；其中，M如上限定。
S2，将正极材料前驱体加乙酰丙酮搅拌均匀形成浆料；
S3，对浆料进行干燥后得到前驱体粉末；
S4，将前驱体粉末置于马弗炉或管式炉内，在600℃～1000℃的空气或氧气气氛中热处理2～24小时；
S5，将热处理后所得粉末进行研磨，得到具有表面原位包覆氧化铜的氧化物复合正极材料。
在第四种方法中，采用溶胶-凝胶法进行制备，主要步骤包括：
S1，将所需钠的化学计量100wt％～110wt％的钠盐，所需铜的化学计量100.1wt％～110wt％的铜的硝酸盐或硫酸盐，所需化学计量的锰和M的硝酸盐或硫酸盐按比例溶于水或者溶于乙醇，混合成前驱体溶液；
其中，M如上限定；钠盐包括：乙酸钠、硝酸钠、碳酸钠或硫酸钠中的一种或几种。
S2，对前驱体溶液在在50℃～100℃下搅拌，并且加入过渡金属的摩尔总量2-6倍的螯合剂，蒸干形成前驱体凝胶，过渡金属包括Cu与M；
S3，将前驱体凝胶置于坩埚中，在200℃～500℃的空气气氛下，预烧2个小时；
S4，再将预烧所得粉末置于马弗炉或管式炉内，在600℃～1000℃的空气或氧气气氛中热处理2～24小时；
S5，将热处理后所得材料进行研磨，得到表面原位包覆氧化铜的氧化物复合正极材料。
在第五种方法中，采用共沉淀法进行制备，主要步骤包括：
S1，将所需铜的化学计量100.1wt％～110wt％的铜的硝酸盐，以及所需化学计量的锰和M的硝酸盐按比例溶于水混合成前驱体溶液；其中，M如上限定。
S2，用蠕动泵将前驱体溶液滴加在pH在7-14之间的氨水溶液中，生成沉淀物；
S3，将得到的沉淀物用去离子水清洗干净，烘干后将沉淀物与所需钠的化学计量100wt％～110wt％的碳酸钠按照化学计量比均匀混合得到前驱物；
S4，将前驱物置于坩埚或瓷舟中，在600℃～1000℃的空气或氧气气氛中热处理2～24小时；
S5，将热处理后所得粉末进行研磨，得到具有表面原位包覆氧化铜的氧化物复合正极材料。
为更好的理解本发明提供的技术方案，下述以多个具体实例分别说明应用本发明上述实施例提供的几种方法制备该原位包覆氧化铜的氧化物复合正极材料的具体过程，以及将其应用于钠离子二次电池的方法和电池特性。
实施例1
本实施例中采用固相法制备原位包覆氧化铜的氧化物复合正极材料。
将所需化学计量的Na 2CO 3(分析纯)、MnO 2(分析纯)，分别与所需铜的化学计量 101wt％的CuO(分析纯)、100wt％的CuO(分析纯)(对比例)按化学计量比混合，分别在玛瑙研钵中球磨半小时，得到两份正极材料前驱体，其中一份CuO过量，一份CuO不过量(作为对比例)得到；
将两份正极材料前驱体分别转移到Al 2O 3坩埚内，在马弗炉中氧气氛围900℃下处理15小时，得到黑色粉末的层状氧化物材料Na 0.67Cu 0.33Mn 0.6O 2(CuO不过量得到)与1％CuO-Na 0.67Cu 0.33Mn 0.6O 2(CuO过量得到)，其XRD图谱参见图2。
从XRD图谱上看,Na 0.67Cu 0.33Mn 0.6O 2与1％CuO-Na 0.67Cu 0.33Mn 0.6O 2的晶体结构均为P2相层状结构的氧化物。其空间群为P63/mmc。
将上述制备得到的原位包覆氧化铜的氧化物复合正极材料作为电池正极材料的活性物质用于钠离子电池的制备：
具体步骤为：将制备好的1％CuO-Na 0.67Cu 0.33Mn 0.6O 2粉末，分别与乙炔黑、粘结剂聚偏氟乙烯(PVDF)按照80:10:10的质量比混合，加入适量的N-甲基吡咯烷酮(NMP)溶液，在常温干燥的环境中研磨形成浆料，然后把浆料均匀涂覆于集流体铝箔上，并在红外灯下干燥后，裁成(8×8)mm 2的极片。极片在真空条件下，110℃干燥10小时，随即转移到手套箱备用。
模拟电池的装配在Ar气氛的手套箱内进行，以金属钠作为对电极，以1mol/L NaClO 4/碳酸二乙酯(DEC)溶液作为电解液，装配成CR2032扣式电池。使用恒流充放电模式，在C/10以及1.0C电流密度下进行充放电测试。在放电截至电压为2.5V，充电截至电压为4.2V的条件下，在2.5-4.2V充放电测试结果见图3，电池循环曲线见图4。
此外，我们还对本实施例1制备所得的表面原位包覆氧化铜的氧化物复合正极材料与未包覆氧化铜的氧化物正极材料在去离子水中浸泡48小时前后进行对比，图5与图6为对比前后的XRD图谱。可以看到经过表面原位包覆氧化铜的氧化物复合正极材料在去离子水中浸泡48小时前后XRD未发生明显变化，而未包覆氧化铜的氧化物正极材料在去离子水中浸泡48小时前后XRD明显发生变化，表明本发明制备所得的表面原位包覆氧化铜的氧化物复合正极材料大大改善了材料对水的稳定性。
将上述在去离子水中浸泡前后得到的层状氧化物材料作为电池正极材料的活性物质用于钠离子电池的制备，并进行电化学充放电测试。其制备过程和测试方法同实施例1，测试电压范围为2.5～4.2V，图7为其充放电测试结果，从充放电曲线以及可逆比容量上来看，包覆层的存在大幅提升了材料对水的稳定性，进一步证明了包覆层的 存在可以提升材料的空气稳定性。
实施例2
本实施例中采用固相法制备原位包覆氧化铜的氧化物复合正极材料。
将所需化学计量的Na 2CO 3(分析纯)、MnO 2(分析纯)、Fe 2O 3(分析纯)，与所需铜的化学计量102wt％的CuO(分析纯)按化学计量比混合；在玛瑙研钵中球磨半小时，得到前驱体；
将前驱体转移到Al 2O 3坩埚内，在马弗炉中氧气氛围900℃下处理15小时，得到黑色粉末的层状氧化物材料2％CuO-Na 0.67Cu 0.22Mn 0.67Fe 0.11O 2，其XRD图谱参见图2。
从XRD图谱上看,2％CuO-Na 0.67Cu 0.22Mn 0.67Fe 0.11O 2晶体结构为P2相层状结构的氧化物。其空间群为P63/mmc。
将上述制备得到的原位包覆氧化铜的氧化物复合正极材料作为电池正极材料的活性物质用于钠离子电池的制备，并进行电化学充放电测试。其制备过程和测试方法同实施例1。测试电压范围为2.5～4.2V，材料的可逆比容量如表1。
实施例3
本实施例中采用固相法制备原位包覆氧化铜的氧化物复合正极材料。
将所需化学计量的Na 2CO 3(分析纯)、Li 2CO 3(分析纯)、NiO(分析纯)、MnO 2(分析纯)，与所需铜的化学计量104wt％的CuO(分析纯)按所需化学计量比混合；在玛瑙研钵中球磨半小时，得到前驱体；
将前驱体转移到Al 2O 3坩埚内，在马弗炉中氧气氛围900℃下处理15小时，得到黑色粉末的层状氧化物材料4％CuO-Na 0.76Li 0.03Ni 0.15Cu 0.18Mn 0.64O 2，其XRD图谱参见图2。
从XRD图谱上看,4％CuO-Na 0.76Li 0.03Ni 0.15Cu 0.18Mn 0.64O 2的晶体结构为P2相层状结构的氧化物。其空间群为P63/mmc。
将上述制备得到的原位包覆氧化铜的氧化物复合正极材料作为电池正极材料的活性物质用于钠离子电池的制备，并进行电化学充放电测试。其制备过程和测试方法同实施例1。测试电压范围为2.5～4.2V，材料的可逆比容量如表1。
实施例4
本实施例中采用固相法制备原位包覆氧化铜的氧化物复合正极材料。
将所需化学计量的Na 2CO 3(分析纯)、、MnO 2(分析纯)、Fe 2O 3(分析纯)、ZnO(分析纯)，与所需铜的化学计量100.5wt％的CuO(分析纯)按所需化学计量比混合；在玛瑙研钵中球磨半小时，得到前驱体；
将前驱体转移到Al 2O 3坩埚内，在马弗炉中氧气氛围900℃下处理15小时，得到黑色粉末的层状氧化物材料0.5％CuO-Na 0.8Cu 0.2Mn 0.63Fe 0.12Zn 0.05O 2，其XRD图谱参见图2。
从XRD图谱上看,0.5％CuO-Na 0.8Cu 0.2Mn 0.63Fe 0.12Zn 0.05O 2的晶体结构为P2/O3混合相结构的氧化物。其空间群为P63/mmc与
Figure PCTCN2022138546-appb-000005
混和。
将上述制备得到的原位包覆氧化铜的氧化物复合正极材料作为电池正极材料的活性物质用于钠离子电池的制备，并进行电化学充放电测试。其制备过程和测试方法同实施例1。测试电压范围为2.5～4.2V，材料的可逆比容量如表1。
实施例5
本实施例中采用固相法制备原位包覆氧化铜的氧化物复合正极材料。
将所需化学计量的Na 2CO 3(分析纯)、MnO 2(分析纯)、TiO 2(分析纯)与所需铜的化学计量107wt％的CuO(分析纯)按所需化学计量比混合；在玛瑙研钵中研磨半小时，得到前驱体；
将前驱体转移到Al 2O 3坩埚内，在马弗炉中氧气氛围900℃下处理15小时，得到黑色粉末的层状氧化物材料7％CuO-Na 1.0Cu 0.5Mn 0.3Ti 0.2O 2，其XRD图谱参见图2。
从XRD图谱上看,7％CuO-Na 1.0Cu 0.5Mn 0.3Ti 0.2O 2的晶体结构为O3状结构的氧化物。其空间群为
Figure PCTCN2022138546-appb-000006
将上述制备得到的原位包覆氧化铜的氧化物复合正极材料作为电池正极材料的活性物质用于钠离子电池的制备，并进行电化学充放电测试。其制备过程和测试方法同
实施例1。测试电压范围为2.5～4.2V，材料的可逆比容量如表1。
Figure PCTCN2022138546-appb-000007
表1
通过对比可以看到，使用本发明制备的原位包覆氧化铜的氧化物复合正极材料在可逆比容量和1.0C循环容量保持率上较没有氧化铜包覆的正极材料性能更优异。
虽然以上实施例仅以固相法为例对本发明方案的具体实施进行了详细说明，但在本发明所提供的喷雾干燥法、燃烧法、溶胶-凝胶法和共沉淀法的制备方法，均为本领域技术人员所熟知的方法，本领域技术人员根据本发明提供的以上制备方法的制备流程步骤，可以在不付出创造性劳动的前提下即可实现本发明的技术方案。
以上所述的具体实施方以上所述的具体实施方式，对本发明的目的、技术方案和有益效果进行了进一步详细说明，所应理解的是，以上所述仅为本发明的具体实施方式而已，并不用于限定本发明的保护范围，凡在本发明的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本发明的保护范围之内。

Claims (10)

  1. 一种原位包覆氧化铜的氧化物复合正极材料，其特征在于，所述原位包覆氧化铜的氧化物复合正极材料的化学通式为：γCuO-Na aCu bMn cM dO 2+β；
    所述氧化物复合正极材料中，Cu、Mn、M共同占据晶体结构中的过渡金属离子位置；M为对过渡金属位进行掺杂取代的元素，包括ⅢA族、Ⅳ主族、VA族元素，以及VIA族的非金属元素中的一种或多种以及第四周期和第五周期的过渡金属元素中的一种或多种；
    所述层状氧化物复合正极材料的空间群为P63/mmc或P63/mcm，对应结构为P2相；或空间群为
    Figure PCTCN2022138546-appb-100001
    对应结构为O3相；或空间群为P63/mmc与
    Figure PCTCN2022138546-appb-100002
    混和，对应结构为或P2/O3混和相；
    所述a，b，c，d，2+β分别为对应元素所占的摩尔百分比，化学通式中各组分满足电荷守恒和化学计量守恒；其中，b+c+d＝1，且a+2b+4c+md＝2(2+β)；0.66≤a≤1；0＜b≤0.5；0＜c≤0.8；0＜d≤0.65；-0.05≤β≤0.05；m为M的化合价态；
    γCuO为烧结制备正极材料过程中，过量添加的Cu元素在Na aCu bMn cM dO 2+β表面原位生成的包覆层，γ为前驱体材料中铜元素过量的摩尔比；其中，0.1％≤γ≤10％。
  2. 根据权利要求1所述的原位包覆氧化铜的氧化物复合正极材料，其特征在于，2％≤γ≤6％。
  3. 根据权利要求1或2所述的原位包覆氧化铜的氧化物复合正极材料的制备方法，其特征在于，所述方法为固相法，包括：
    将所需钠的化学计量100wt％～108wt％的碳酸钠、所需铜的化学计量100.1wt％～110wt％的铜的氧化物、所需化学计量的锰和M的氧化物或碳酸盐混合成正极材料前驱体；所述M为对过渡金属位进行掺杂取代的元素，包括ⅢA族、Ⅳ主族、VA族元素，以及VIA族的非金属元素中的一种或多种以及第四周期和第五周期的过渡金属元素中的一种或多种；
    采用球磨的方式将所述正极材料前驱体均匀混合得到前驱体粉末；
    将所述前驱体粉末置于马弗炉或管式炉内，在600℃～1000℃的空气或氧气气氛中热处理2～24小时；
    将热处理后所得粉末进行研磨，得到所述原位包覆氧化铜的氧化物复合正极材 料。
  4. 根据权利要求1或2所述的原位包覆氧化铜的氧化物复合正极材料的制备方法，其特征在于，所述方法为喷雾干燥法，包括：
    将所需钠的化学计量100wt％～110wt％的碳酸钠或硝酸钠、所需铜的化学计量100.1wt％～110wt％的铜的硝酸盐、所需化学计量的锰的硝酸盐和M的氧化物或碳酸混合成正极材料前驱体；所述M为对过渡金属位进行掺杂取代的元素，包括ⅢA族、Ⅳ主族、VA族元素，以及VIA族的非金属元素中的一种或多种以及第四周期和第五周期的过渡金属元素中的一种或多种；
    将所述正极材料前驱体加乙醇或水后搅拌均匀形成浆料；
    对所述浆料进行喷雾干燥后得到前驱体粉末；
    将所述前驱体粉末置于马弗炉或管式炉内，在600℃～1000℃的空气或氧气气氛中热处理2～24小时；
    将热处理后所得粉末进行研磨，得到所述表面原位包覆氧化铜的氧化物复合正极材料。
  5. 根据权利要求1或2所述的原位包覆氧化铜的氧化物复合正极材料的制备方法，其特征在于，所述方法为燃烧法，包括：
    将所需钠的化学计量100wt％～110wt％的硝酸钠、所需铜的化学计量100.1wt％～110wt％的铜的硝酸盐、所需化学计量的锰和M的硝酸盐混合成正极材料前驱体；所述M为对过渡金属位进行掺杂取代的元素，包括ⅢA族、Ⅳ主族、VA族元素，以及VIA族的非金属元素中的一种或多种以及第四周期和第五周期的过渡金属元素中的一种或多种；
    将所述正极材料前驱体加乙酰丙酮搅拌均匀形成浆料；
    对所述浆料进行干燥后得到前驱体粉末；
    将所述前驱体粉末置于马弗炉或管式炉内，在600℃～1000℃的空气或氧气气氛中热处理2～24小时；
    将热处理后所得粉末进行研磨，得到所述具有表面原位包覆氧化铜的氧化物复合正极材料。
  6. 根据权利要求1或2所述的原位包覆氧化铜的氧化物复合正极材料的制备方 法，其特征在于，所述方法为溶胶-凝胶法，包括：
    将所需钠的化学计量100wt％～110wt％的钠盐，所需铜的化学计量100.1wt％～110wt％的铜的硝酸盐或硫酸盐，所需化学计量的锰和M的硝酸盐或硫酸盐按比例溶于水或者溶于乙醇，混合成前驱体溶液；所述M为对过渡金属位进行掺杂取代的元素，包括ⅢA族、Ⅳ主族、VA族元素，以及VIA族的非金属元素中的一种或多种以及第四周期和第五周期的过渡金属元素中的一种或多种；所述钠盐包括：乙酸钠、硝酸钠、碳酸钠或硫酸钠中的一种或几种；
    对所述前驱体溶液在在50℃～100℃下搅拌，并且加入过渡金属的摩尔总量2-6倍的螯合剂，蒸干形成前驱体凝胶；过渡金属包括Cu与M；
    将所述前驱体凝胶置于坩埚中，在200℃～500℃的空气气氛下，预烧2个小时；
    再将预烧所得粉末置于马弗炉或管式炉内，在600℃～1000℃的空气或氧气气氛中热处理2～24小时；
    将热处理后所得材料进行研磨，得到所述表面原位包覆氧化铜的氧化物复合正极材料。
  7. 根据权利要求1或2所述的原位包覆氧化铜的氧化物复合正极材料的制备方法，其特征在于，所述方法为共沉淀法，包括：
    将所需铜的化学计量100.1wt％～110wt％的铜的硝酸盐，以及所需化学计量的锰和M的硝酸盐按比例溶于水混合成前驱体溶液；所述M为对过渡金属位进行掺杂取代的元素，包括ⅢA族、Ⅳ主族、VA族元素，以及VIA族的非金属元素中的一种或多种以及第四周期和第五周期的过渡金属元素中的一种或多种；
    用蠕动泵将所述前驱体溶液滴加在pH在7-14之间的氨水溶液中，生成沉淀物；
    将得到的沉淀物用去离子水清洗干净，烘干后将所述沉淀物与所需钠的化学计量100wt％～110wt％的碳酸钠按照化学计量比均匀混合得到前驱物；
    将所述前驱物置于坩埚或瓷舟中，在600℃～1000℃的空气或氧气气氛中热处理2～24小时；
    将热处理后所得粉末进行研磨，得到所述具有表面原位包覆氧化铜的氧化物复合正极材料。
  8. 一种钠离子二次电池的正极极片，其特征在于，所述正极极片包括：集流体、涂覆于所述集流体之上的导电添加剂、粘结剂和上述权利要求1或2所述的原位包覆氧化铜的氧化物复合正极材料。
  9. 一种包括上述权利要求8所述的正极极片的钠离子二次电池。
  10. 一种上述权利要求9所述的钠离子二次电池的用途，其特征在于，所述钠离子二次电池用于太阳能发电、风力发电、智能电网调峰、分布电站、后备电源或通信基站的大规模储能设备。
PCT/CN2022/138546 2022-09-27 2022-12-13 原位包覆氧化铜的氧化物复合正极材料、制备方法和用途 WO2024066064A1 (zh)

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