A single-phase spinel-type high-entropy oxide lithium-ion battery anode material, its preparation method and application

Abstract

This invention discloses a single-phase spinel-type high-entropy oxide lithium-ion battery anode material, its preparation method, and its application, belonging to the field of lithium-ion battery technology. The preparation method of this anode material includes: weighing nitrates of Fe, Co, Ni, Zn, and Mg, and cetyltrimethylammonium bromide, adding them to water, and stirring to dissolve them to obtain solution A; then adding a precipitant and mixing evenly to obtain solution B; after hydrothermal reaction, separating the supernatant and precipitate, washing the precipitate with water and ethanol, and drying it to obtain a solid precursor material; sintering the solid precursor material, cooling, and then pulverizing it to obtain the lithium-ion battery anode material. This invention improves the electrochemical performance of the anode material by introducing Zn and Mg elements with well-matched atomic radii to the main elements and by controlling the material morphology. The coin-type lithium-ion battery assembled with this anode material exhibits excellent long-term cycle performance and rate performance over a wide temperature range.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, specifically to a single-phase spinel-type high-entropy oxide lithium-ion battery anode material, its preparation method, and its application. Background Technology

[0002] Currently, in the field of battery technology, lithium-ion batteries have become the main electrochemical system for energy storage due to their advantages such as high open-circuit voltage, long cycle life, high energy density, and no memory effect. The anode material is crucial for improving battery performance; however, graphite, the anode material in traditional commercial lithium-ion batteries, suffers from low capacity (372 mAh·g). -1 The current technology cannot meet the market demand for large-scale power batteries and energy storage batteries. Developing new lithium-ion battery anode materials has become a hot topic.

[0003] Given the shortcomings of the aforementioned materials, researchers are dedicated to developing novel anode materials to achieve higher specific capacity and superior electrochemical reaction kinetics. Against this backdrop, high-entropy materials, due to their advantages such as high structural disorder, strong compositional controllability, and stable structure and mechanical properties, have become a promising new class of electrode materials, enabling the regulation of electrochemical reaction active sites and operating voltage, and suppressing structural collapse and electrode pulverization during charge and discharge processes. High-entropy compound anodes possess diverse crystal structures, such as spinel, rock salt, perovskite, and fluorite, among which the spinel structure stands out for its unique advantages: it contains two distinct Wyckoff sites, allowing for a wide range of valence state changes during charge and discharge, thus achieving high specific capacity; simultaneously, the spinel structure is more thermodynamically stable, endowing the anode material with excellent cycle performance.

[0004] In recent years, significant progress has been made in the research of high-entropy oxides as anode materials for lithium-ion batteries. For example, Nguyen et al. synthesized spinel-structured high-entropy oxides (Co) via a surfactant-assisted hydrothermal method. 0.2 Cr 0.2 Fe 0.2 Mn 0.2 Ni 0.2 )3O4, and applied to lithium-ion battery anode materials, with an initial discharge specific capacity as high as 1235 mAh·g -1 And at 0.5 A·g -1 After 200 cycles at a current density of 2 A·g, the capacity retention rate is as high as 90%; -1 At current densities, the reversible specific capacity remains as high as 500 mAh·g. -1 Chen et al. used in-situ synchrotron X-ray absorption spectroscopy to analyze in detail the spinel structure of high-entropy oxide (Ni). 0.2 Co 0.2 Mn0.2 Fe 0.2 Ti 0.2 The lithium storage mechanism of 3O4 involves the conversion of some transition metal ions into metallic Ni during discharge. 0 Co 0 Mn 0 and Fe 0 Ti ions, as inactive components, remain stable in the original structure to form LiTi2O4. During lithiation, the spinel structure helps maintain structural stability. During delithiation, most of the metallic nanoparticles are re-oxidized into the spinel structure. In addition, due to the entropy stabilization effect, the material exhibits relatively small volume expansion during the reaction, demonstrating good structural stability.

[0005] Despite the great potential of high-entropy oxide anode materials in terms of performance, further optimization is still needed in terms of discharge specific capacity, reaction reversibility, and cycle stability. At the same time, the complexity of elemental composition and the disorder of atomic arrangement of high-entropy materials pose new challenges to the study of the structure-property relationship between material composition, material structure and electrochemical performance, as well as their application over a wide temperature range. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a single-phase spinel-type high-entropy oxide lithium-ion battery anode material, its preparation method, and its applications. This invention addresses the issue that high-entropy oxides, currently a hot research topic, contain many elements with mismatched atomic radii, preventing the formation of a single-phase structure. These materials often exhibit impurities, uneven atomic / molecular distribution, and the presence of highly toxic elements (such as Cr), leading to poor low-temperature performance in lithium-ion batteries. This invention introduces Zn and Mg, elements with well-matched atomic radii to the main elements, to form a single-phase structure. By modifying the reaction conditions to control the material morphology, the electrochemical performance of the high-entropy oxide anode material is further improved.

[0007] This invention provides a single-phase spinel-type high-entropy oxide lithium-ion battery anode material, its preparation method, and its application, employing the following technical solution: In a first aspect, the present invention provides a method for preparing a single-phase spinel-type high-entropy oxide lithium-ion battery anode material, comprising the following steps: Step 1): Weigh out the nitrates of Fe, Co, Ni, Zn, and Mg and cetyltrimethylammonium bromide (CTAB), add them to water, and stir to dissolve to obtain solution A; Step 2): Add a precipitant to solution A obtained in step 1) and mix thoroughly to obtain solution B; Step 3): After the solution B obtained in Step 2) undergoes a hydrothermal reaction, the supernatant and precipitate are separated. The precipitate is washed with water and ethanol and dried to obtain a solid precursor material. Step 4): Sinter the solid precursor material obtained in Step 3), cool it, and then pulverize it to obtain a single-phase spinel-type high-entropy oxide lithium-ion battery anode material.

[0008] Preferably, in step 1), the molar ratio of Fe:Co:Ni:Zn:Mg:CTAB is 1:1:1:1:1:0.6~0.8; and the stirring is performed by magnetic stirring for 10~30 min.

[0009] Preferably, in step 2), the precipitant is urea.

[0010] Preferably, in step 2), the molar ratio of the precipitant to Fe, Co, Ni, Zn, and Mg is 10~20:1:1:1:1:1.

[0011] Preferably, in step 3), the hydrothermal reaction is carried out by heating at 120~200℃ for 8~24 hours.

[0012] Preferably, in step 4), sintering is performed by heating at 600~900℃ for 1~6 hours in an air atmosphere.

[0013] Preferably, in step 4), the material is crushed into uniform and fine dust particles by grinding in a mortar and pestle.

[0014] In a second aspect, the present invention provides a single-phase spinel-type high-entropy oxide lithium-ion battery anode material prepared by the above-described preparation method.

[0015] In a third aspect, the present invention provides an application of the above-mentioned single-phase spinel-type high-entropy oxide lithium-ion battery anode material to prepare lithium-ion batteries suitable for a wide temperature range.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention introduces Zn and Mg, two inexpensive and non-toxic elements with good atomic radius matching to the host elements, and leverages the high-entropy effect to induce moderate lattice distortion, thereby generating more oxygen vacancies and ion transport channels. The precursor is synthesized via a high-temperature hydrothermal method, followed by high-temperature sintering to form single-phase spinel-type high-entropy oxide nanoparticles (FeCoNiZnMg)3O4 (FCNZMO) with an average particle size of 40 nm. The single-phase structure exhibits strong structural stability and excellent process adaptability, thus effectively regulating oxygen vacancy concentration, improving electrical conductivity, enhancing electrochemical performance, and significantly improving cycle stability over a wide temperature range of 0.5 A·g. -1 Cycling at current density for 150 cycles, 2 A·g -1 It maintains a high discharge specific capacity even after 300 cycles at current density. Attached Figure Description

[0017] Figure 1 The X-ray diffraction (XRD) pattern of the single-phase spinel-type high-entropy oxide powder prepared in Example 1 of this invention. Figure 2 This is a scanning electron microscope (SEM) image of the single-phase spinel-type high-entropy oxide powder prepared in Example 1 of the present invention. Figure 3 This is an energy dispersive X-ray spectral elemental distribution analysis image (EDS) of the single-phase spinel-type high-entropy oxide powder prepared in Example 1 of the present invention. Figure 4 After the single-phase spinel-type high-entropy oxide powder prepared in Example 1 of this invention was assembled into a coin cell lithium-ion battery, it was tested at room temperature (25°C) and 0.5 A·g. -1 Long-cycle performance at current density; Figure 5 After the single-phase spinel-type high-entropy oxide powder prepared in Example 1 of this invention was assembled into a coin cell lithium-ion battery, it was tested at room temperature (25°C) and 2 A·g -1 Long-cycle performance at current density; Figure 6 After the single-phase spinel-type high-entropy oxide powder prepared in Example 1 of this invention was assembled into a coin cell lithium-ion battery, it was tested at room temperature (25°C) and at a speed of 0.1~5 A·g. -1 Rate performance at current density; Figure 7 The fitted electrochemical impedance spectroscopy (EIS) at room temperature (25°C) is obtained after the single-phase spinel-type high-entropy oxide powder prepared in Example 1 of this invention is assembled into a coin-type lithium-ion battery. Figure 8 After the single-phase spinel-type high-entropy oxide powder prepared in Example 1 of this invention was assembled into a coin cell lithium-ion battery, it was tested at a low temperature (-10°C) and 0.5 A·g -1 Long-cycle performance at current density; Figure 9 After the single-phase spinel-type high-entropy oxide powder prepared in Example 1 of this invention was assembled into a coin cell lithium-ion battery, it was subjected to low temperature (-10°C) and 2A·g -1 Long-cycle performance at current density. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. The preferred embodiments and their descriptions are for illustrative purposes only and are not intended to limit the invention. Unless otherwise specified, specific conditions in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, all reagents or instruments used are commercially available and readily available products.

[0019] This invention provides a single-phase spinel-type high-entropy oxide lithium-ion battery anode material, its preparation method, and its application. Nitrates of Fe, Co, Ni, Zn, and Mg, and CTAB are weighed and added to water, stirred, and dissolved to obtain solution A. A precipitant is then added and mixed thoroughly to obtain solution B. After a hydrothermal reaction, the supernatant and precipitate are separated. The precipitate is washed with water and ethanol and dried to obtain a solid precursor material. The solid precursor material is sintered, cooled, and then pulverized to obtain the single-phase spinel-type high-entropy oxide lithium-ion battery anode material. This invention improves the electrochemical performance of the anode material by introducing Zn and Mg elements with well-matched atomic radii to the main elements and by controlling the material morphology. The coin-type lithium-ion battery assembled with this anode material exhibits excellent long-term cycle performance and rate performance over a wide temperature range.

[0020] Example 1 This invention provides a method for preparing a single-phase spinel-type high-entropy oxide lithium-ion battery anode material, comprising the following steps: (1) Weigh 1 mmol of Fe(NO3)3·9H2O, Co(NO3)2·6H2O, Ni(NO3)2·6H2O, Zn(NO3)2·6H2O and Mg(NO3)2·6H2O respectively, and weigh 0.8 mmol of CTAB; measure 40 mL of deionized water into a 100 mL beaker, place the above drugs in the deionized water, and stir magnetically for 15 min to dissolve them to obtain solution A; (2) Add 20 mmol of urea to solution A, mix well, and obtain solution B; (3) Place the completely dissolved solution B in a 100 mL hydrothermal reactor and react in a heating box at a temperature of 150 °C for 14 h. After the heating box cools to room temperature, remove it and pour out the supernatant from the hydrothermal reactor. Take out the precipitate from the hydrothermal reactor and place it in a centrifuge tube. Add anhydrous ethanol and deionized water to wash it. Centrifuge at 8000 rpm for 5 min. Repeat the washing process 3 times. Place the washed precipitate in a 60 °C oven to dry it and obtain the solid precursor material. (4) The solid precursor material was placed in a muffle furnace under air atmosphere at 5°C / min. -1 Sinter at 650℃ for 1 hour. After the muffle furnace cools to room temperature, remove the sintered high-entropy oxide material and place it in a mortar. Manually grind it into uniform and fine dust particles to obtain a single-phase spinel-type high-entropy oxide lithium-ion battery anode material.

[0021] Example 2 This invention provides a method for preparing a single-phase spinel-type high-entropy oxide lithium-ion battery anode material, comprising the following steps: (1) Weigh 1 mmol of Fe(NO3)3·9H2O, Co(NO3)2·6H2O, Ni(NO3)2·6H2O, Zn(NO3)2·6H2O and Mg(NO3)2·6H2O respectively, and weigh 0.65 mmol of CTAB; measure 40 mL of deionized water into a 100 mL beaker, place the above drugs in the deionized water, and stir magnetically for 30 min to obtain solution A; (2) Add 14 mmol of urea to solution A, mix well, and obtain solution B; (3) Place the completely dissolved solution B in a 100mL hydrothermal reactor and react in a heating box at a temperature of 160℃ for 12 hours. After the heating box cools to room temperature, remove it and pour out the supernatant from the hydrothermal reactor. Take out the precipitate from the hydrothermal reactor and place it in a centrifuge tube. Add anhydrous ethanol and deionized water to wash it. Centrifuge at 8000rpm for 5 minutes. Repeat the washing process 3 times. Place the washed precipitate in a 60℃ oven to dry it and obtain the solid precursor material. (4) The solid precursor material was placed in a muffle furnace under air atmosphere at 5°C / min. -1 Sinter at 600℃ for 1 hour. After the muffle furnace cools to room temperature, remove the sintered high-entropy oxide material and place it in a mortar. Grind it manually into uniform and fine dust particles to obtain a single-phase spinel-type high-entropy oxide lithium-ion battery anode material.

[0022] Example 3 This invention provides a method for preparing a single-phase spinel-type high-entropy oxide lithium-ion battery anode material, comprising the following steps: (1) Weigh 1 mmol of Fe(NO3)3·9H2O, Co(NO3)2·6H2O, Ni(NO3)2·6H2O, Zn(NO3)2·6H2O and Mg(NO3)2·6H2O respectively, and weigh 0.6 mmol of CTAB; measure 40 mL of deionized water into a 100 mL beaker, place the above drugs in the deionized water, and stir magnetically for 30 min to obtain solution A; (2) Add 18 mmol of urea to solution A, mix well, and obtain solution B; (3) Place the completely dissolved solution B in a 100mL hydrothermal reactor and react in a heating box at a temperature of 130℃ for 15h. After the heating box cools to room temperature, remove it and pour out the supernatant from the hydrothermal reactor. Take out the precipitate from the hydrothermal reactor and place it in a centrifuge tube. Add anhydrous ethanol and deionized water to wash it. Centrifuge at 8000rpm for 5min. Repeat the washing process 3 times. Place the washed precipitate in a 60℃ oven to dry it and obtain the solid precursor material. (4) The solid precursor material was placed in a muffle furnace under air atmosphere at 5°C / min. -1 Sinter at 700℃ for 1 hour. After the muffle furnace cools to room temperature, remove the sintered high-entropy oxide material and place it in a mortar. Grind it manually into uniform and fine dust particles to obtain a single-phase spinel-type high-entropy oxide lithium-ion battery anode material.

[0023] Various experimental tests were conducted on the single-phase spinel-type high-entropy oxide lithium-ion battery anode material prepared in Example 1: like Figure 1 As shown, the X-ray diffraction (XRD) structural test results indicate that the anode material has a single-phase spinel structure and good crystallinity.

[0024] like Figure 2 As shown, the scanning electron microscope characterization results indicate that the negative electrode material has a spherical structure with a particle size of about 40 nm and a uniform distribution.

[0025] like Figure 3 As shown, the elemental distribution analysis (EDS) results of energy dispersive X-ray spectroscopy indicate that the elements in this anode material are uniformly distributed.

[0026] like Figure 4 As shown, after assembling the single-phase spinel-type high-entropy oxide lithium-ion battery anode material obtained in Example 1 into a coin cell lithium-ion battery, it was tested at room temperature (25°C) and 0.5 A·g. -1 Long-cycle testing at current density revealed that the initial discharge specific capacity was 1016.9 mAh·g. -1 And after 150 cycles, it still has a high capacity of 705.6 mAh·g. -1 Its discharge specific capacity demonstrates excellent cycle performance.

[0027] like Figure 5 As shown, after assembling the single-phase spinel-type high-entropy oxide lithium-ion battery anode material obtained in Example 1 into a coin cell lithium-ion battery, it was tested at room temperature (25°C) and 2A·g. -1 Long-cycle testing at current density showed that the discharge specific capacity after 300 cycles was 644.2 mAh·g. -1 With a capacity retention rate of up to 87%, it demonstrates excellent cycle performance.

[0028] like Figure 6 As shown, after assembling the single-phase spinel-type high-entropy oxide lithium-ion battery anode material obtained in Example 1 into a coin cell lithium-ion battery, it was tested at room temperature (25°C) and at a speed of 0.1~5 A·g. -1 Rate performance testing at current densities shows that the discharge specific capacity only slightly decreases during uninterrupted testing from low to high current densities, and the capacity increases only slightly when the current density returns to 0.5 A·g.-1 The post-charge / discharge specific capacity also basically recovered to the initial 0.5 A·g. -1 Its specific capacity exhibits excellent rate stability.

[0029] like Figure 7 As shown, after assembling the single-phase spinel-type high-entropy oxide lithium-ion battery anode material obtained in Example 1 into a coin-type lithium-ion battery, the electrochemical impedance spectroscopy was tested and fitted under room temperature (25°C) conditions (R0). s R represents ohmic impedance. ct As can be seen from the charge transfer impedance, the impedance increases from 59.26Ω in the 3rd cycle to 221Ω in the 150th cycle. As the cycle proceeds steadily, the dynamics of the cycle process are enhanced.

[0030] like Figure 8 As shown, after assembling the single-phase spinel-type high-entropy oxide lithium-ion battery anode material obtained in Example 1 into a coin cell lithium-ion battery, it was tested at low temperature (-10°C) and 0.5 A·g -1 Long-cycle testing at current density revealed that the initial discharge specific capacity was 552.9 mAh·g. -1 And after 100 cycles, it still has a high capacity of 386.7 mAh·g. -1 It has a high discharge specific capacity with only slight capacity decay, making it promising for applications at low temperatures.

[0031] like Figure 9 As shown, after assembling the single-phase spinel-type high-entropy oxide lithium-ion battery anode material obtained in Example 1 into a coin cell lithium-ion battery, it was tested at low temperature (-10°C) and 2A·g. -1 Long-term cycling tests at current density show that the discharge specific capacity is 273.3 mAh·g after 150 cycles. -1 With a capacity retention rate of 21.6%, it shows promise for application at low temperatures.

[0032] Table 1 shows the performance test results of the single-phase spinel-type high-entropy oxide lithium-ion battery anode material prepared in Example 1 after being assembled into a coin-type lithium-ion battery. Table 1 Performance Test Results

[0033] As shown in Table 1, after introducing Zn and Mg, which have good matching atomic radii with the main elements, the prepared single-phase spinel-type high-entropy oxide lithium-ion battery anode material induces more oxygen vacancies and ion transport channels by means of lattice distortion caused by the high-entropy effect. The coin-type lithium-ion battery assembled based on this anode material exhibits excellent long-cycle stability and rate performance at room temperature, and also shows good performance at low temperature, with promising application prospects in a wide temperature range.

[0034] It should be noted that the above embodiments are intended to illustrate the substantive content of the present invention, but are not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and protection of the present invention.

Claims

1. A method for preparing a single-phase spinel-type high-entropy oxide lithium-ion battery anode material, characterized in that, Includes the following steps: Step 1): Weigh out the nitrates of Fe, Co, Ni, Zn, and Mg and hexadecyltrimethylammonium bromide respectively, add them to water, stir and dissolve to obtain solution A; Step 2): Add a precipitant to solution A obtained in step 1) and mix thoroughly to obtain solution B; Step 3): After the solution B obtained in Step 2) undergoes a hydrothermal reaction, the supernatant and precipitate are separated. The precipitate is washed with water and ethanol and dried to obtain a solid precursor material. Step 4): Sinter the solid precursor material obtained in Step 3), cool it, and then pulverize it to obtain a single-phase spinel-type high-entropy oxide lithium-ion battery anode material.

2. The preparation method according to claim 1, characterized in that, In step 1), the molar ratio of Fe:Co:Ni:Zn:Mg:hexadecyltrimethylammonium bromide is 1:1:1:1:1:0.6~0.8; Stir with magnetic stirring for 10-30 minutes.

3. The preparation method according to claim 1, characterized in that, In step 2), the precipitant is urea.

4. The preparation method according to claim 1, characterized in that, In step 2), the molar ratio of the precipitant to Fe, Co, Ni, Zn, and Mg is 10~20:1:1:1:1:

1.

5. The preparation method according to claim 1, characterized in that, In step 3), the hydrothermal reaction is carried out by heating at 120~200℃ for 8~24 hours.

6. The preparation method according to claim 1, characterized in that, In step 4), sintering is performed by heating at 600-900°C for 1-6 hours in an air atmosphere.

7. The preparation method according to claim 1, characterized in that, In step 4), the powder is crushed into uniform and fine dust particles by grinding in a mortar.

8. A single-phase spinel-type high-entropy oxide lithium-ion battery anode material, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 7.

9. The application of a single-phase spinel-type high-entropy oxide lithium-ion battery anode material as described in claim 8, characterized in that, To prepare lithium-ion batteries suitable for a wide temperature range.

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