Aluminate positive electrode material and preparation method and application thereof

Abstract

The application relates to the technical field of aluminum ion batteries, in particular to an aluminate positive electrode material and a preparation method and application thereof. The chemical formula of the aluminate positive electrode material is MAl2O4; the structure of the aluminate positive electrode material is a spinel structure, and the space group is Fd-3m; M represents one or more of Ni, Co and Fe. The stability of the aluminate positive electrode material is higher through optimization of the structure of the aluminate positive electrode material, the aluminate positive electrode material has the ability of simultaneously storing aluminum ions, chlorine ions and hydrogen ions, and the specific capacity, cycle performance and rate performance of the battery can be significantly improved.

Description

Technical Field

[0001] This invention relates to the field of aluminum-ion battery technology, and in particular to an aluminate cathode material, its preparation method, and its application. Background Technology

[0002] With the emergence of the energy crisis and the subsequent development of tidal, geothermal, wind, and solar energy, energy storage materials have become increasingly important. Among devices for storing clean energy, lithium-ion batteries, with their advantages of high voltage, high cycle stability, and high energy density, are widely used. Although lithium-ion batteries appear to be the most efficient charging devices and have attracted extensive research over the past 30 years, they cannot fully meet the ever-increasing demand for energy storage. Commercialized lithium-ion batteries will eventually approach their theoretical energy density and may reach maturity in the near future. Furthermore, improvements to lithium-ion batteries are limited by raw material reserves; the uneven distribution of raw materials, with lithium ranking only 27th among the most abundant elements in the Earth's crust, restricts the continued development of lithium-ion batteries. In addition, during charging and discharging, lithium dendrites form on the electrode surface and eventually puncture the separator, leading to short circuits and heat release. In recent years, catastrophic failures of lithium-ion batteries have caused enormous losses, raising public concern about their safety risks.

[0003] The aforementioned drawbacks limit the application of lithium-ion batteries in large-scale, stationary energy storage, leading to a shift in research focus towards developing next-generation energy storage devices as alternatives to lithium-ion batteries. Aluminum, however, possesses a very high capacity (8046 mAh / cm³). 3 Aluminum, far exceeding several other elements, has a higher standard reduction potential (-1.66V) compared to other metals. Due to the potential three-electron transfer process, rechargeable aluminum batteries exhibit high energy density. In terms of sustainability, aluminum is the cheapest of all metals (only 1 / 150th the cost of lithium) and is the third most abundant element in the Earth's crust. Aluminum ions have the smallest cation radius (0.535 Å), leading to favorable transport kinetics. Due to its high electronegativity, aluminum exhibits lower reactivity and higher safety in air and moisture compared to other metals, particularly lithium or sodium. Aluminum-ion batteries are considered a promising type of multivalent ion battery.

[0004] Currently, research on cathode materials for aluminum-ion batteries mainly focuses on transition metal oxides, Prussian blue analogues, organic compounds, and graphite materials. These materials suffer from drawbacks such as low capacity, poor cycle stability, and poor rate performance, leaving significant room for improvement before commercialization. Therefore, to achieve the secondary commercialization of aluminum-ion batteries, further research and exploration of cathode materials are needed. Finding an aluminum-ion battery cathode material with long cycle life, high capacity, low production cost, and simple preparation process has become a research hotspot and key issue in aluminum-ion battery development.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] In fact, current research focuses primarily on lithium-ion and sodium-ion batteries, with only a few researchers studying aluminum-ion batteries. Among these few, due to the varied structures of manganese-based oxides, their widespread distribution in the Earth's crust, and their low cost, most aluminum-ion batteries incorporate manganese doping. However, this invention reveals that manganese in the electrode material easily disintegrates in the electrolyte, leading to battery failure, capacity reduction, and poor stability. This invention, however, discovers that aluminate cathode materials with a spinel structure and space group Fd-3m exhibit higher stability and the ability to simultaneously store aluminum, chloride, and hydrogen ions, significantly improving the battery's specific capacity, cycle performance, and rate performance.

[0007] The specific technical solution of the present invention is as follows:

[0008] In a first aspect, the present invention provides an aluminate cathode material, wherein the aluminate cathode material has a spinel structure and a space group of Fd-3m.

[0009] Preferably, the aluminate cathode material has the chemical formula MAl2O4; M represents one or more of Ni, Co and Fe.

[0010] This invention discovers that when the aluminate cathode material for aluminum-ion batteries contains one or more of Ni, Co, and Fe (but does not contain manganese), it is possible to prepare a spinel-structured aluminate cathode material with space group Fd-3m.

[0011] Secondly, the present invention provides a method for preparing the above-mentioned aluminate cathode material, comprising: mixing an aluminum source, a metal M source and a solvent to obtain a precursor solution; and then subjecting the precursor solution to spray drying and sintering in sequence to obtain the aluminate cathode material; M represents one or more of Ni, Co and Fe.

[0012] The preparation method described in this invention has the advantages of simple process, low cost and environmental friendliness, and is suitable for large-scale industrial production.

[0013] Furthermore, the mixing operation can be carried out by mechanical stirring to ensure uniform mixing, preferably with a stirring speed of 200 to 2000 rpm.

[0014] Furthermore, the mixing temperature is 20–80°C.

[0015] Preferably, the sintering includes sequentially performing low-temperature sintering, grinding, and high-temperature sintering; wherein the sintering temperature of the low-temperature sintering is 300–600°C; and the sintering temperature of the high-temperature sintering is 700–1600°C.

[0016] Preferably, the heating rate for the low-temperature sintering is 1–10 °C / min; and the heating rate for the high-temperature sintering is 1–15 °C / min.

[0017] Furthermore, the low-temperature sintering and the high-temperature sintering are respectively followed by heat preservation, the heat preservation time for the low-temperature sintering is 2 to 12 hours; the heat preservation time for the high-temperature sintering is 2 to 96 hours.

[0018] In practice, those skilled in the art can use conventional grinding equipment, such as a universal grinder, to perform the grinding operation. Preferably, the grinding time is 0.5 to 8 hours, and the grinding speed is 200 to 4000 rpm.

[0019] Preferably, when the molar ratio of the aluminum source to the metal M source is (1-2):(1-2), it is beneficial to form a precursor with small particles, which in turn is beneficial to improve performance; more preferably, it is 1:1.

[0020] When the metal source M contains multiple metals, the preferred molar ratio of the different metal sources M is (1-2):(1-2). For example, when the metal source M is ferrous oxalate, nickel sulfate, and cobalt sulfate, the molar ratio of ferrous oxalate, nickel sulfate, and cobalt sulfate is (1-2):(1-2):(1-2); more preferably, it is 1:1:1.

[0021] Preferably, the inlet air temperature of the spray dryer is 200-400℃, the outlet air temperature is 80-180℃, and the flow rate is 50-8000mL / h.

[0022] Preferably, the aluminum source includes one or more of aluminum nitrate, aluminum chloride, aluminum sulfate, and aluminum trifluoromethanesulfonate; the anion in the metal M source is one or more of sulfate ion, chloride ion, aminosulfonate ion, bromide ion, nitrate ion, and acetate ion; and the solvent includes water and / or ethanol.

[0023] More preferably, the aluminum source is aluminum nitrate or aluminum sulfate; the anions in the metal M source are nitrate ions and sulfate ions.

[0024] Preferably, the preparation method of the present invention further includes: cooling after high-temperature sintering, followed by crushing, sieving, and demagnetizing. Further, a 200-400 mesh sieve is selected during the sieving process, and even more specifically, a 300 mesh sieve is selected.

[0025] As a preferred embodiment of the present invention, the preparation method includes: mixing aluminum sulfate, metal M source and water to obtain a precursor solution; then subjecting the precursor solution to spray drying, low-temperature sintering, grinding and high-temperature sintering in sequence, and cooling to obtain the aluminate cathode material;

[0026] The molar ratio of the aluminum source to the metal M source is (1-1.5):(1-1.5); the anion in the metal M source is sulfate ion; the inlet air temperature of the spray drying is 200-300℃, the outlet air temperature is 90-110℃, and the flow rate is 50-90mL / min; the heating rate of the low-temperature sintering is 4-6℃ / min, the low-temperature sintering temperature is 300-600℃, and the holding time is 10-12h; the grinding time is 3-5h, and the grinding speed is 200-400rpm; the heating rate of the high-temperature sintering is 4-6℃ / min, the temperature is 700-1600℃, and the holding time is 11-13h.

[0027] Thirdly, the present invention provides an aluminum-ion battery containing the aforementioned aluminate cathode material.

[0028] Preferably, the aluminum-ion battery includes a negative electrode, a positive electrode, a separator, and an electrolyte, wherein the positive electrode includes an aluminate positive electrode material, a conductive agent, a binder, and a current collector, wherein the mass ratio of the aluminate positive electrode material, the conductive agent, and the binder is 80-95:2-10:3-10.

[0029] Furthermore, the conductive agent may be carbon black and / or acetylene black, and the binder may be polyvinylidene fluoride and / or polytetrafluoroethylene.

[0030] Furthermore, the coating density of the positive electrode is 0.1–20 mg / cm³. 2 Preferably 1–18 mg / cm³ 2 More preferably 3–15 mg / cm³ 2 .

[0031] Fourthly, the present invention provides applications of the aluminum-ion battery in energy storage power stations, start-stop power supplies, mobile power supplies, electric two-wheelers, electric boats, electric vehicles, and hybrid electric vehicles.

[0032] Based on the above technical solution, the beneficial effects of the present invention are as follows:

[0033] This invention optimizes the structure of aluminate cathode materials, making them more stable and capable of simultaneously storing aluminum ions, chloride ions, and hydrogen ions, thereby significantly improving the battery's specific capacity, cycle performance, and rate performance. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0035] Figure 1 This is the XRD pattern of the NiAl2O4 cathode material prepared in Example 1 of this invention;

[0036] Figure 2 This is a graph showing the cycling performance of the NiAl2O4 cathode material prepared in Example 1 of this invention at a current density of 100 mA / g.

[0037] Figure 3 This is a graph showing the cycling performance of the NiAl2O4 cathode material prepared in Example 1 of this invention at a current density of 500 mA / g.

[0038] Figure 4 This is a cycle performance diagram of the CoAl2O4 cathode material prepared in Example 2 of the present invention;

[0039] Figure 5 This is a cycle performance diagram of the FeAl2O4 cathode material prepared in Example 3 of the present invention;

[0040] Figure 6 The Fe prepared in Example 4 of this invention 1 / 3 Ni 1 / 3 Co 1 / 3 Cycle performance diagram of Al2O4 cathode material;

[0041] Figure 7 The Fe prepared in Example 5 of this invention 1 / 2 Ni 1 / 2 Cycle performance diagram of Al2O4 cathode material;

[0042] Figure 8 The Co prepared in Example 6 of this invention 1 / 2 Ni 1 / 2 Cycle performance diagram of Al2O4 cathode material;

[0043] Figure 9 This is a cycle performance diagram of the NiAl2O4 cathode material prepared in Example 7 of the present invention;

[0044] Figure 10 This is a discharge curve of the aqueous aluminum-ion battery prepared in Example 8 of the present invention;

[0045] Figure 11The Co prepared in Comparative Example 1 provided by this invention 1 / 2 Mn 1 / 2 XRD pattern of Al2O4 cathode material;

[0046] Figure 12 The Co prepared in Comparative Example 1 provided by this invention 1 / 2 Mn 1 / 2 Cyclic performance diagram of Al2O4 cathode material. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0048] Unless otherwise specified, all raw materials used in the embodiments are commercially available conventional raw materials, and the technical means used are conventional means well known to those skilled in the art.

[0049] Example 1

[0050] This embodiment first provides an aluminate cathode material, the preparation method of which includes the following steps:

[0051] (1) Disperse aluminum sulfate and nickel sulfate in a molar ratio of 1:1 into deionized water and stir mechanically to obtain a homogeneous precursor solution with a metal ion concentration of 1 mol / L.

[0052] (2) The precursor solution was spray-dried using an airflow atomizing dryer with an inlet air temperature of 220℃, an outlet air temperature of 110℃, and a peristaltic pump flow rate of 60mL / min to obtain precursor powder. The precursor powder was then mechanically ground until uniform and placed in a high-temperature sintering furnace. The temperature was increased to 600℃ at a heating rate of 5℃ / min and held for 12 hours. After cooling, zirconia balls and pre-sintered powder were placed in a zirconia jar at a ball-to-material ratio of 20:1 and ball-milled for 4 hours at a speed of 300rpm. The ball-milled pre-sintered powder was then placed in a high-temperature sintering furnace and heated to 1100℃ at a heating rate of 5℃ / min and held for 12 hours. After cooling, the powder was pulverized for 5 minutes, sieved through a 300-mesh sieve, and demagnetized using a demagnetizer to obtain NiAl2O4 cathode material.

[0053] The crystal structure of NiAl2O4 cathode material was analyzed using XRD technology, see [link / reference]. Figure 1 As shown, according to standard PDF card 10-0339, the material has a cubic nickel-aluminum spinel structure with space group Fd-3m.

[0054] This embodiment further provides an aluminum-ion battery, the preparation method of which includes the following steps:

[0055] NiAl2O4 cathode material, super carbon black, polyvinylidene fluoride (PVDF), and N-methylpyrrolidone (NMP) solution were mixed evenly at a mass ratio of 80:10:10:25 to form a slurry with an areal density of 4 mg / cm³. 2 The material was uniformly coated onto titanium foil and vacuum dried at 120°C for 12 hours to obtain a NiAl2O4 positive electrode. Electrochemical performance was tested using a three-electrode simulated battery, with a platinum electrode as the counter electrode, a silver / silver chloride electrode as the reference electrode, and an aqueous aluminum chloride solution as the electrolyte.

[0056] Charge-discharge tests were conducted at room temperature with a current density of 100 mA / g, and the test voltage range was 0–1.2 V. The cycle performance test results of the NiAl₂O₄ cathode material are shown below. Figure 2 The initial discharge capacity was 217 mAh / g, which increased to 232 mAh / g after 50 cycles.

[0057] Charge-discharge tests were conducted at room temperature with a current density of 500 mA / g, and the test voltage range was 0–1.2 V. The cycle performance test results of the NiAl₂O₄ cathode material are shown below. Figure 3 The initial discharge capacity is 194 mAh / g, which increases to 196 mAh / g after 50 cycles.

[0058] Example 2

[0059] This embodiment first provides an aluminate cathode material, the preparation method of which includes the following steps:

[0060] (1) Disperse aluminum sulfate and cobalt sulfate in a molar ratio of 1:1 into deionized water and stir mechanically to obtain a uniform precursor solution with a metal ion concentration of 1 mol / L.

[0061] (2) The precursor solution was spray-dried using an airflow atomizing dryer with an inlet air temperature of 220℃, an outlet air temperature of 110℃, and a peristaltic pump flow rate of 60mL / min to obtain precursor powder. The precursor powder was then mechanically ground until uniform and placed in a high-temperature sintering furnace. The temperature was increased to 600℃ at a heating rate of 5℃ / min and held for 12 hours. After cooling, zirconia balls and pre-sintered powder were placed in a zirconia jar at a ball-to-material ratio of 20:1 and ball-milled for 4 hours at a speed of 300rpm. The ball-milled pre-sintered powder was placed in a high-temperature sintering furnace and heated to 800℃ at a heating rate of 5℃ / min and held for 12 hours. After cooling, the powder was pulverized for 5 minutes, sieved through a 300-mesh sieve, and demagnetized using a demagnetizer to obtain CoAl2O4 cathode material.

[0062] This embodiment further provides an aluminum-ion battery, the preparation method of which includes the following steps:

[0063] CoAl2O4 cathode material, super carbon black, polyvinylidene fluoride (PVDF), and N-methylpyrrolidone (NMP) solution were mixed evenly in a mass ratio of 80:10:10:25 to form a slurry. This slurry was then uniformly coated onto titanium foil and vacuum dried at 120°C for 12 hours to obtain the cathode sheet with a coating density of 4 mg / cm². 2 Electrochemical performance was tested using a three-electrode simulated battery. A platinum electrode was used as the counter electrode, a silver / silver chloride electrode was used as the reference electrode, and an aqueous solution of aluminum chloride was used as the electrolyte.

[0064] Charge-discharge tests were conducted at room temperature with a current density of 100 mA / g, and the test voltage range was 0–1.2 V. The cycle performance test results of the CoAl2O4 cathode material are shown below. Figure 4 The initial discharge capacity is 80mAh / g, which increases to 135mAh / g after 50 cycles.

[0065] Example 3

[0066] This embodiment first provides an aluminate cathode material, the preparation method of which includes the following steps:

[0067] (1) Disperse aluminum hydroxide and ferrous oxalate in a molar ratio of 1:1 into deionized water and stir mechanically to obtain a uniform precursor solution with a metal ion concentration of 1 mol / L.

[0068] (2) The precursor solution was spray-dried using an airflow atomizing dryer with an inlet air temperature of 220℃, an outlet air temperature of 110℃, and a peristaltic pump flow rate of 60mL / min to obtain precursor powder. The precursor powder was then mechanically ground until uniform and placed in a high-temperature sintering furnace. The temperature was increased to 300℃ at a rate of 5℃ / min and held for 10 hours. After cooling, zirconia balls and pre-sintered powder were placed in a zirconia container at a ball-to-material ratio of 20:1 and ball-milled for 4 hours at a speed of 300rpm. The ball-milled pre-sintered powder was then placed in a high-temperature sintering furnace and heated to 1300℃ at a rate of 5℃ / min and held for 12 hours. After cooling, the powder was pulverized for 5 minutes, sieved through a 300-mesh sieve, and demagnetized using a demagnetizer to obtain FeAl2O4 cathode material.

[0069] This embodiment further provides an aluminum-ion battery, the preparation method of which includes the following steps:

[0070] FeAl2O4 cathode material, super carbon black, polyvinylidene fluoride (PVDF), and N-methylpyrrolidone (NMP) solution were mixed evenly in a mass ratio of 80:10:10:25 to form a slurry. This slurry was then uniformly coated onto titanium foil and vacuum dried at 120°C for 12 hours to obtain the cathode sheet with a coating density of 4 mg / cm². 2 Electrochemical performance was tested using a three-electrode simulated battery. A platinum electrode was used as the counter electrode, a silver / silver chloride electrode was used as the reference electrode, and an aqueous solution of aluminum chloride was used as the electrolyte.

[0071] Charge-discharge tests were conducted at room temperature with a current density of 100 mA / g, and the test voltage range was 0–1.2 V. The cycle performance test results of the FeAl2O4 cathode material are shown below. Figure 5 The initial discharge capacity is 242 mAh / g, which increases to 339 mAh / g after 50 cycles.

[0072] Example 4

[0073] This embodiment first provides an aluminate cathode material, the preparation method of which includes the following steps:

[0074] (1) Disperse aluminum sulfate, ferrous oxalate, nickel sulfate and cobalt sulfate in a molar ratio of 3:1:1:1 into deionized water and stir mechanically to obtain a homogeneous precursor solution with a metal ion concentration of 1 mol / L.

[0075] (2) The precursor solution was spray-dried using an airflow atomizing dryer with an inlet air temperature of 220℃, an outlet air temperature of 110℃, and a peristaltic pump flow rate of 60mL / min to obtain precursor powder. The precursor powder was then mechanically ground until homogeneous and placed in a high-temperature sintering furnace. The temperature was increased to 300℃ at a rate of 5℃ / min and held for 10 hours. After cooling, zirconia balls and pre-sintered powder were placed in a zirconia container at a ball-to-powder ratio of 20:1 and ball-milled for 4 hours at 300rpm. The pre-sintered powder was then placed in a high-temperature sintering furnace and heated to 1300℃ at a rate of 5℃ / min, held for 12 hours, cooled, and pulverized for 5 minutes. The powder was then sieved through a 300-mesh sieve and demagnetized using a demagnetizer to obtain Fe. 1 / 3 Ni 1 / 3 Co 1 / 3 Al2O4 cathode material.

[0076] This embodiment further provides an aluminum-ion battery, the preparation method of which is the same as in Example 1. Charge-discharge tests were conducted at room temperature with a current density of 100 mA / g, and the test voltage range was 0–1.2 V. Fe 1 / 3 Ni 1 / 3 Co 1 / 3 Cyclic performance testing of Al2O4 cathode material is shown in [link to test results]. Figure 6The results showed that the initial discharge capacity was 120 mAh / g, which increased to 172 mAh / g after 50 cycles.

[0077] Example 5

[0078] This embodiment first provides an aluminate cathode material, the preparation method of which includes the following steps:

[0079] (1) Disperse aluminum sulfate, ferrous oxalate and nickel sulfate in a molar ratio of 2:1:1 into deionized water and stir mechanically to obtain a homogeneous precursor solution with a metal ion concentration of 1 mol / L.

[0080] (2) The precursor solution was spray-dried using an airflow atomizing dryer with an inlet air temperature of 220℃, an outlet air temperature of 110℃, and a peristaltic pump flow rate of 60mL / min to obtain precursor powder. The precursor powder was then mechanically ground until homogeneous and placed in a high-temperature sintering furnace. The temperature was increased to 300℃ at a rate of 5℃ / min and held for 10 hours. After cooling, zirconia balls and pre-sintered powder were placed in a zirconia container at a ball-to-powder ratio of 20:1 and ball-milled for 4 hours at 300rpm. The pre-sintered powder was then placed in a high-temperature sintering furnace and heated to 1300℃ at a rate of 5℃ / min, held for 12 hours, cooled, and pulverized for 5 minutes. The powder was then sieved through a 300-mesh sieve and demagnetized using a demagnetizer to obtain Fe. 0.5 Ni 0.5 Al2O4 cathode material.

[0081] This embodiment further provides an aluminum-ion battery, the preparation method of which is the same as in Example 1. Charge-discharge tests were conducted at room temperature with a current density of 100 mA / g, and the test voltage range was 0–1.2 V. Fe 0.5 Ni 0.5 Cyclic performance testing of Al2O4 cathode material is shown in [link to test results]. Figure 7 The results showed that the initial discharge capacity was 112 mAh / g, which increased to 177 mAh / g after 50 cycles.

[0082] Example 6

[0083] This embodiment first provides an aluminate cathode material, the preparation method of which includes the following steps:

[0084] (1) Disperse aluminum sulfate, cobalt sulfate and nickel sulfate in a molar ratio of 2:1:1 into deionized water and stir mechanically to obtain a homogeneous precursor solution with a metal ion concentration of 1 mol / L.

[0085] (2) The precursor solution was spray-dried using an airflow atomizing dryer with an inlet air temperature of 220℃, an outlet air temperature of 110℃, and a peristaltic pump flow rate of 60mL / min to obtain precursor powder. The precursor powder was then mechanically ground until homogeneous and placed in a high-temperature sintering furnace. The temperature was increased to 300℃ at a rate of 5℃ / min and held for 10 hours. After cooling, zirconia balls and pre-sintered powder were placed in a zirconia jar at a ball-to-powder ratio of 20:1 and ball-milled for 4 hours at 300rpm. The ball-milled pre-sintered powder was then placed in a high-temperature sintering furnace and heated to 1300℃ at a rate of 5℃ / min, held for 12 hours, cooled, and pulverized for 5 minutes. The powder was then sieved through a 300-mesh sieve and demagnetized using a demagnetizer to obtain Ni. 0.5 Co 0.5 Al2O4 cathode material.

[0086] This embodiment further provides an aluminum-ion battery, the preparation method of which is the same as in Example 1. Charge-discharge tests were conducted at room temperature with a current density of 100 mA / g, and the test voltage range was 0–1.2 V. 0.5 Co 0.5 Cyclic performance testing of Al2O4 cathode material is shown in [link to test results]. Figure 8 The results showed that the initial discharge capacity was 92 mAh / g, which increased to 163 mAh / g after 50 cycles.

[0087] Example 7

[0088] This embodiment first provides an aluminate cathode material, the preparation method of which is the same as that in Example 1, the only difference being that: during sintering, the precursor powder is mechanically ground uniformly, and then directly heated to 1100℃ at a heating rate of 5℃ / min and held for 12 hours; finally, NiAl2O4 cathode material is obtained.

[0089] This embodiment further provides an aluminum-ion battery, the preparation method of which is the same as in Example 1. Charge-discharge tests were conducted at room temperature with a current density of 100 mA / g, and the test voltage range was 0–1.2 V. The cycle performance test of the NiAl2O4 cathode material is shown in [reference needed]. Figure 9 The results showed that the initial discharge capacity was 75 mAh / g, which increased to 134 mAh / g after 50 cycles.

[0090] Example 8

[0091] An aqueous aluminum-ion battery was fabricated using the NiAl2O4 positive electrode, aluminum negative electrode, glass fiber separator, aluminum chloride aqueous electrolyte, and aluminum-plastic film shell provided in Example 1.

[0092] Charge-discharge tests were conducted at room temperature with a current density of 500 mA / g, and the voltage range was 0–1.9 V. The test results are shown below. Figure 10 At a current density of 500 mA / g, the battery's operating voltage plateau is 1.55V and 1.08V, with an initial discharge capacity of 103.2 mAh / g and a discharge capacity of 30 mAh / g after 50 cycles. Therefore, it is a promising energy storage device.

[0093] Comparative Example 1

[0094] This comparative example first provides an aluminate cathode material, the preparation method of which is the same as that in Example 5, except that nickel sulfate is replaced with an equal amount of manganese sulfate; finally, Co is obtained. 0.5 Mn 0.5 Al2O4 cathode material.

[0095] Ni was analyzed using XRD technology 0.5 Mn 0.5 The crystal structure of Al2O4 cathode material is shown below. Figure 11 As shown, the material has a spinel structure and a space group of P4332.

[0096] This embodiment further provides an aluminum-ion battery, the preparation method of which is the same as in Example 1. Charge-discharge tests were conducted at room temperature with a current density of 100 mA / g, and the test voltage range was 0–1.2 V. 0.5 Mn 0.5 The cycle performance test results of the Al2O4 cathode material are shown in [the table]. Figure 12 The initial discharge capacity was 102.6 mAh / g, which decreased to 83.4 mAh / g after 50 cycles.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An aluminate cathode material, characterized in that, The aluminate cathode material has a spinel structure and a space group of Fd-3m.

2. The aluminate cathode material according to claim 1, characterized in that, The chemical formula of the aluminate cathode material is MAl2O4; M represents one or more of Ni, Co and Fe.

3. The method for preparing the aluminate cathode material according to claim 1 or 2, characterized in that, include: An aluminum source, a metal M source, and a solvent are mixed to obtain a precursor solution; The precursor solution is then spray-dried and sintered sequentially to obtain the aluminate cathode material; M represents one or more of Ni, Co and Fe.

4. The method for preparing the aluminate cathode material according to claim 3, characterized in that, The sintering process includes sequentially performing low-temperature sintering, grinding, and high-temperature sintering; wherein the sintering temperature for low-temperature sintering is 300–600°C; and the sintering temperature for high-temperature sintering is 700–1600°C.

5. The method for preparing the aluminate cathode material according to claim 4, characterized in that, The heating rate for the low-temperature sintering is 1–10 °C / min; the heating rate for the high-temperature sintering is 1–15 °C / min.

6. The method for preparing the aluminate cathode material according to any one of claims 3 to 5, characterized in that, The molar ratio of the aluminum source to the metal M source is (1-2):(1-2).

7. The method for preparing the aluminate cathode material according to any one of claims 3 to 6, characterized in that, The spray dryer has an inlet air temperature of 200–400°C, an outlet air temperature of 80–180°C, and a flow rate of 50–8000 mL / h.

8. The method for preparing the aluminate cathode material according to any one of claims 3 to 7, characterized in that, The aluminum source includes one or more of aluminum nitrate, aluminum chloride, aluminum sulfate, and aluminum trifluoromethanesulfonate; the anion in the metal M source is one or more of sulfate ion, chloride ion, aminosulfonate ion, bromide ion, nitrate ion, and acetate ion; the solvent includes water and / or ethanol.

9. An aluminum-ion battery, characterized in that, The aluminate cathode material contained in claim 1 or 2 or the aluminate cathode material prepared by any one of claims 3 to 8.

10. The aluminum-ion battery according to claim 9, characterized in that, The aluminum-ion battery includes a negative electrode, a positive electrode, a separator, and an electrolyte. The positive electrode includes an aluminate positive electrode material, a conductive agent, a binder, and a current collector. The mass ratio of the aluminate positive electrode material, the conductive agent, and the binder is 80–95:2–10:3–10.

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