Binary transition metal composite negative electrode material and preparation method thereof
By constructing an alloying system of Sb and In2S3, the structural instability of alloyed anode materials caused by volume expansion in sodium-ion batteries was solved, achieving high cycle life and excellent discharge performance of the material.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUANGZHOU UNIVERSITY
- Filing Date
- 2023-06-09
- Publication Date
- 2026-07-07
Smart Images
Figure CN116730382B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery anode material technology, and in particular to a binary transition metal composite anode material and its preparation method. Background Technology
[0002] Lithium-ion batteries have become the preferred choice for chemical energy storage due to their high energy density and power density. It is reported that lithium-ion battery energy storage accounts for as much as 94.5% of new energy storage installations nationwide. However, given that current global lithium production capacity cannot meet demand, and lithium resources are mainly concentrated in South America, in order to gain the initiative in energy storage, in addition to continuing to strongly support the development of lithium batteries, it is also necessary to develop other types of batteries. Sodium-ion batteries have similar redox potentials and energy storage mechanisms to lithium-ion batteries, and metallic sodium resources are relatively abundant, thus they are expected to become a new generation of energy storage devices. However, although sodium-ion batteries have been industrialized, they can only be applied in limited scenarios. One important factor restricting the development of sodium-ion batteries is that commercial graphite is not suitable as a negative electrode material for sodium batteries; therefore, it is necessary to explore and find suitable negative electrode materials for sodium batteries.
[0003] Alloy-type anode materials refer to materials that can undergo alloying and dealloying reactions with metallic sodium during charge and discharge. These are primarily elements from Groups IV and V, such as phosphorus (P) and silicon (Si) with high theoretical capacity, germanium (Ge) and tin (Sn) with relatively low operating voltages, and antimony (Sb) and bismuth (Bi) with good stability. All of these elements can undergo alloying reactions with metallic sodium, and their sodiumization voltages are generally below 1V, making them promising anode materials for sodium-ion batteries. However, alloy-type anode materials exhibit significant volume expansion, which often has several negative impacts on battery performance. First, the solid electrolyte interface formed during charge and discharge can rupture due to the material's volume expansion, exposing a new interface to the active material that was originally encapsulated by the SEI film. This exposed interface often requires electrolyte to form a new solid electrolyte film, resulting in lower coulombic efficiency. Second, the continuous contraction and expansion of the active material can lead to rupture, pulverization, and agglomeration, making it prone to detachment from the current collector and affecting electrochemical performance. Furthermore, even though silicon and phosphorus have very high theoretical capacity, as non-metallic elements, their conductivity is worse than that of metals, which makes their actual performance poor. Summary of the Invention
[0004] The purpose of this invention is to provide a binary transition metal composite anode material and its preparation method, which can solve the above-mentioned technical problems.
[0005] This invention provides a method for preparing a binary transition metal composite anode material, comprising the following steps:
[0006] Step 1: Disperse few-layer MXene, In(NO3)3 and SbCl3 in ethylene glycol by ultrasonication;
[0007] Step 2: Disperse thiourea in ethylene glycol by physical stirring;
[0008] Step 3: Mix the solution obtained in Step 1 with the solution obtained in Step 2 and stir until homogeneous to obtain a mixture. Transfer the mixture to a hydrothermal reactor lined with polytetrafluoroethylene for reaction.
[0009] Step 4: After the reaction in Step 3 is completed, wait for it to cool to room temperature and remove the liner. Centrifuge the solution obtained in Step 3 to obtain the precipitate, wash it, and dry it to obtain the intermediate product MXene@(SbIn)S.
[0010] Step 5: Place the intermediate product MXene@(SbIn)S obtained in Step 4 into a ceramic boat and anneal it in a tube furnace filled with inert gas. After annealing is completed, the target product MXene@Sb / In2S3 is obtained.
[0011] Preferably, the molar ratio of In(NO3)3 to SbCl3 in step 1 is 1:1.
[0012] Preferably, in step 2, the molar ratio of thiourea to In(NO3)3 is 6.25:1.
[0013] Preferably, in step 3, the solution obtained in step 1 is mixed with the solution obtained in step 2 and stirred for 4 hours.
[0014] Preferably, the reaction conditions in step 3 are: reaction at 200°C in a forced-air oven for 32 hours.
[0015] Preferably, the cleaning process in step 4 is to first wash with deionized water three times, and then wash with anhydrous ethanol three times; or to first wash with anhydrous ethanol three times, and then wash with deionized water three times.
[0016] Preferably, the drying time in step 4 is 12 hours.
[0017] Preferably, the annealing temperature in step 5 is 450°C.
[0018] Preferably, the heating rate during the annealing process is 2°C / minute, and the holding time is 6 hours.
[0019] The present invention also provides a binary transition metal composite anode material prepared by the above preparation method.
[0020] To mitigate the significant volume expansion of alloyed anode materials during charging and discharging, in-situ alloying systems within the anode material have proven to be an effective and feasible strategy. Alloying systems typically refer to the combination of an electrochemically active metal with another elemental substance to form an intermetallic compound. Sb is commonly alloyed with Bi, Sn, Cu, Zn, etc., and used in sodium-ion batteries. Among the many metals that alloy with Sb, indium-antimony (In-Sb) alloys are particularly attractive due to their high theoretical capacity (In's theoretical specific capacity is 467 mAh g / g). -1 Besides its high theoretical specific capacity, In exhibits strong plasticity, with an elongation rate of up to 60% and a shrinkage rate of up to 22%. This means that In can effectively mitigate the effects of volume expansion and contraction during cycling. To address these issues, an alloying system is constructed, utilizing the alloying / dealloying potentials of two different metals to act as buffers, ensuring the structural stability of the electrode material.
[0021] The beneficial effects of this invention are:
[0022] During the charging and discharging process, the binary transition metal composite anode material of this invention, because both Sb and In2S3 are alloy materials, the generated Sb and In elements eventually form the InSb phase, constructing an alloy system. This system can act as a buffer to ensure the stability of the electrode material structure, greatly reduce the volume expansion during charging and discharging, and improve the cycle life and stability of the material. Attached Figure Description
[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0024] Figure 1 This is a flowchart illustrating the preparation of MXene@Sb / In2S3 according to the present invention;
[0025] Figure 2 This is a scanning electron microscope image of MXene@(SbIn)S prepared in this invention;
[0026] Figure 3 This is the X-ray diffraction pattern of MXene@(SbIn)S prepared in this invention;
[0027] Figure 4 Here is a scanning electron microscope image of MXene@Sb / In2S3 prepared in this invention;
[0028] Figure 5This is the X-ray diffraction pattern of MXene@Sb / In2S3 prepared in this invention;
[0029] Figure 6 This is a graph showing the long-cycle performance of MXene@Sb / In2S3 prepared in this invention;
[0030] Figure 7 This is a rate performance diagram of MXene@Sb / In2S3 prepared in this invention. Detailed Implementation
[0031] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.
[0032] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0033] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0034] Example 1
[0035] A method for preparing a binary transition metal composite anode material:
[0036] I. Synthesis of MXene@(SbIn)S
[0037] (1) The few-layer MXene (90 mg), In(NO3)3 (0.8 mmol), and SbCl3 (0.8 mmol) were ultrasonically dispersed in 80 mL of ethylene glycol (EG) for 30 min.
[0038] (2) Thiourea (CH4N2S, 5 mmol) was dispersed in 80 mL of EG by physical stirring;
[0039] (3) Mix the solution from step (1) with the solution from step (2) and stir for 4 hours. Transfer the mixture to a polytetrafluoroethylene liner and cover it with a hydrothermal reactor. React in a 200°C forced-air oven for 32 hours.
[0040] (4) After cooling to room temperature, remove the liner, centrifuge the solution from step (3), wash it three times each with deionized water and anhydrous ethanol, and dry it to obtain the intermediate product MXene@(SbIn)S. The scanning electron microscope image of MXene@(SbIn)S is shown below. Figure 2 As shown, the X-ray diffraction pattern is as follows: Figure 3 As shown.
[0041] 2. Synthesis of MXene@Sb2S3 / In2S3
[0042] (5) Place the MXene@(SbIn)S obtained in step (4) into a porcelain boat and anneal it in a tube furnace filled with inert gas. The annealing temperature is 450℃, the heating rate is 2℃ per minute, and the holding time is 6h. After annealing is completed, the target product MXene@Sb / In2S3 can be obtained. The scanning electron microscope image of MXene@Sb / In2S3 is shown below. Figure 4 As shown, the X-ray diffraction pattern is as follows: Figure 5 As shown.
[0043] Note: MXene: Ti3C2; MXene@(SbIn)S: MXene@Sb2S3 / In2S3.
[0044] When MXene@Sb / In2S3 is used as the negative electrode of a sodium-ion battery, such as Figure 6 As shown, at a high current density of 1 A / g, the MXene@Sb / In2S3 anode material maintains a discharge specific capacity of 328.4 mAh / g after 1000 cycles. Figure 7 As shown, in rate performance testing, the MXene@Sb / In2S3 anode material exhibited discharge specific capacities of 801, 411, 377, 349, 330, and 309 mAh / g at current densities of 0.1, 0.2, 0.5, 1.0, 2.0, and 5.0 A / g, respectively. When the current density returned to 0.1 A / g, the discharge specific capacity returned to 400 mAh / g.
[0045] In process one, MXene@(SbIn)S is prepared via a one-step hydrothermal method. The surface of MXene has abundant negatively charged functional groups, such as -OH and -F. The metal source is In. 3+ and Sb 3+ It can connect with negatively charged functional groups, thereby enabling In 3+ and Sb 3+ It can anchor on the MXene surface, and the addition of thiourea can convert metal ions into corresponding metal sulfides under high temperature and pressure, ultimately generating MXene@(SbIn)S.
[0046] In process two, MXene@(SbIn)S undergoes prolonged low-temperature annealing, reducing Sb₂S₃ to elemental Sb, yielding the final product MXene@Sb / In₂S₃. During charge and discharge, because both Sb and In₂S₃ are alloy materials, the generated elemental Sb and In ultimately form the InSb phase, constructing an alloyed system. This system acts as a buffer to ensure the structural stability of the electrode material, significantly reducing volume expansion during charge and discharge, and improving the cycle life and stability of the material.
[0047] The final prepared MXene@Sb / In2S3 electrode material was mixed and ground uniformly with binder (PVDF, polyvinylidene fluoride) and conductive carbon black at a mass ratio of 7:1:2. N-methylpyrrolidone (NMP) was then added and ground into a slurry, which was then coated onto copper foil. Using metallic sodium as the negative electrode, glass fiber as the separator, and 1.0M NaPF6 DEM as the electrolyte, a sodium-ion battery was assembled in an argon-filled glove box. After assembly, its electrochemical performance (long-cycle performance and rate performance) was tested using a Neware testing system, with a test voltage range of 0.01-2.7V. After charge-discharge testing, as shown... Figure 6 and 7 As shown, the MXene@Sb / In2S3 electrode material maintains a discharge specific capacity of 328.4 mAh / g after 1000 cycles at a high current density of 1 A / g. At current densities of 0.1, 0.2, 0.5, 1.0, 2.0, and 5.0 A / g, it exhibits discharge specific capacities of 801, 411, 377, 349, 330, and 309 mAh / g, respectively. When the current density returns to 0.1 A / g, the discharge specific capacity recovers to 400 mAh / g, demonstrating excellent cycle reversibility.
[0048] 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 or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for preparing a binary transition metal composite anode material, characterized in that, Includes the following steps: Step 1: Disperse few-layer MXene, In(NO3)3 and SbCl3 in ethylene glycol by ultrasonication, with the molar ratio of In(NO3)3 to SbCl3 being 1:1; Step 2: Disperse thiourea in ethylene glycol by physical stirring, with a molar ratio of thiourea to In(NO3)3 of 6.25:1; Step 3: Mix the solution obtained in Step 1 with the solution obtained in Step 2 and stir until homogeneous to obtain a mixture. Transfer the mixture to a hydrothermal reactor lined with polytetrafluoroethylene for reaction. Step 4: After the reaction in Step 3 is completed, the liner is removed after cooling to room temperature. The solution obtained in Step 3 is centrifuged to obtain the precipitate, which is then washed and dried to obtain the intermediate product MXene@(SbIn)S. Step 5: Place the intermediate product MXene@(SbIn)S obtained in Step 4 into a ceramic boat and anneal it in a tube furnace filled with inert gas. After annealing is completed, the target product MXene@Sb / In2S3 is obtained.
2. The preparation method of the binary transition metal composite anode material according to claim 1, characterized in that, In step 3, the solution obtained in step 1 is mixed with the solution obtained in step 2 and stirred for 4 hours.
3. The method for preparing the binary transition metal composite anode material according to claim 1, characterized in that, The reaction conditions in step 3 are as follows: reaction at 200 °C in a forced-air oven for 32 h.
4. The method for preparing the binary transition metal composite anode material according to claim 1, characterized in that, The cleaning process in step 4 is to first wash with deionized water three times, and then wash with anhydrous ethanol three times; or to first wash with anhydrous ethanol three times, and then wash with deionized water three times.
5. The method for preparing the binary transition metal composite anode material according to claim 1, characterized in that, The drying time in step 4 is 12 hours.
6. The method for preparing the binary transition metal composite anode material according to claim 1, characterized in that, The annealing temperature in step 5 is 450 ℃.
7. The method for preparing the binary transition metal composite anode material according to claim 1, characterized in that, The annealing process involves a heating rate of 2 °C / min and a holding time of 6 h.
8. The binary transition metal composite anode material prepared by the preparation method according to any one of claims 1-7.