Fast-charging aluminum negative electrode material based on stepped temperature lithiation and preparation method of fast-charging aluminum negative electrode material

Abstract

The invention provides a preparation method of a fast-charging aluminum negative electrode material based on stepped temperature lithiation, which comprises the following steps: (S1) placing an aluminum foil with a surface oxide layer removed in a first lithiation reagent, and forming a LiAl phase on the surface of the aluminum foil under a low-temperature condition to obtain a first pre-lithiated aluminum foil; (S2) putting the aluminum foil subjected to primary pre-lithiation into a second lithiation reagent, and partially converting a LiAl phase into a lithium-aluminum alloy phase with higher lithium content under a high-temperature condition, so as to obtain aluminum foil subjected to secondary pre-lithiation; and (S3) washing and drying the aluminum foil subjected to secondary pre-lithiation to obtain the fast-charging aluminum negative electrode material. According to the invention, a lithiation process of first low temperature and then high temperature in steps is adopted, so that controllable and stable construction of the gradient alloy layer is realized, and the interfacial ion transport kinetics and fast charge performance of the aluminum negative electrode are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion batteries, specifically relating to a fast-charging aluminum anode material based on stepped temperature lithiation and its preparation method. Background Technology

[0002] Lithium-ion batteries, as highly efficient electrochemical energy storage devices, have been widely used in portable electronic devices, electric vehicles, and energy storage systems. With the increasing demands for charging efficiency in end-use applications, the development of novel anode materials with excellent fast-charging performance has become a research hotspot. Traditional graphite anodes are limited by their relatively low theoretical capacity (372 mAh g⁻¹). -1 The operating voltage, which is close to the lithium deposition potential, can easily induce lithium dendrite growth during high-current charging, posing a safety hazard.

[0003] Among numerous alternative materials, aluminum anodes stand out due to their high theoretical capacity (993 mAh g⁻¹). -1 Based on the LiAl alloying reaction, and with a suitable operating potential (0.3–0.4 V vs. Li), + With its advantages such as low cost and abundant reserves, aluminum anodes (Li₂O₃) show promising application prospects. However, the practical application of aluminum anodes still faces two key challenges: First, the dense alumina (Al2O3) insulating layer naturally formed on the surface of metallic aluminum severely hinders the lithiation reaction. This oxide layer not only significantly increases interfacial impedance but also inhibits the migration of lithium ions at the interface, making conventional chemical pre-lithiation methods difficult to carry out effectively below 60°C. This results in incomplete and uneven pre-lithiation reactions, directly affecting the coulombic efficiency and rate performance of the negative electrode.

[0004] Secondly, existing pre-lithiation technologies (such as physical pre-lithiation and electrochemical pre-lithiation) are typically carried out only at room temperature, resulting in a low-lithium-content LiAl alloy phase on the aluminum surface. This phase has limited intrinsic ionic conductivity, which cannot meet the requirements of high-rate charge and discharge. More importantly, a single-depth lithium-aluminum alloy layer undergoes significant volume changes during cycling, leading to electrode pulverization and rapid capacity decay, thus limiting its fast-charging performance and cycle stability.

[0005] CN119833615A discloses a high-performance silicon-aluminum composite anode material, comprising an aluminum-containing compound and nano-silicon particles uniformly attached to a framework structure formed by the aluminum-containing compound; the aluminum-containing compound includes aluminum powder and / or a lithium-aluminum alloy, wherein the lithium-aluminum alloy is obtained through pre-lithiation treatment. CN116544359A discloses an aluminum-based anode and its preparation method, wherein a pre-lithiation technique is used to convert Al2O3 on the Al2O3 layer of the aluminum foil of the aluminum-based anode into Li2O3 completely covering the electrode surface. x AlO yA pre-lithiated aluminum-based anode is obtained by layering y=2, 0<x≤1. CN111326717A discloses an aluminum anode material, the preparation method of which involves coating a slurry composed of a lithium-donating material, a binder, and optionally a conductive agent onto the surface of an aluminum anode substrate, drying it, and obtaining an aluminum anode material with a pre-lithiated coating on the surface. The above patents all involve the process of pre-lithiating aluminum anodes, but as mentioned above, the pre-lithiation of aluminum anodes has defects: the pre-lithiation reaction is incomplete and uneven; the low lithium content LiAl alloy phase has low conductivity, and significant volume changes occur during cycling, leading to electrode pulverization and rapid capacity decay.

[0006] While current improvement strategies have alleviated the volume expansion problem to some extent through nanostructuring or composite structure design, it remains difficult to construct alloy layers with compositional gradients on the aluminum surface, failing to simultaneously address the challenges of interfacial lithiation and slow bulk kinetics. Existing processes are often complex and costly, hindering large-scale fabrication. Summary of the Invention

[0007] To address the aforementioned problems, this invention provides a fast-charging aluminum anode material based on stepped-temperature lithiation and its preparation method. Employing a stepwise lithiation process, it achieves controllable and stable construction of the gradient alloy layer, significantly improving the interfacial ion transport kinetics and fast-charging performance of the aluminum anode. Specifically, this invention achieves the above objectives through the following technical solutions: A method for preparing a fast-charging aluminum anode material based on stepped temperature lithiation includes the following steps: (S1) The aluminum foil with the surface oxide layer removed is placed in the first lithiation reagent, and under low temperature conditions, a LiAl phase is formed on the surface of the aluminum foil to obtain the first pre-lithiation aluminum foil; (S2) The aluminum foil that has been pre-lithiated for the first time is placed in the second lithiation reagent. Under high temperature conditions, the LiAl phase is partially transformed into a lithium-aluminum alloy phase with a higher lithium content, thus obtaining the aluminum foil that has been pre-lithiated for the second time. (S3) The aluminum foil pre-lithiated for the second time is washed and dried to obtain the fast-charging aluminum anode material.

[0008] Further, in step (S1), the method for removing the surface oxide layer includes immersing the aluminum foil in an acidic or alkaline solution to react the surface aluminum oxide into soluble aluminum salts for removal. The acid salts include, but are not limited to, hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, phosphoric acid, benzoic acid, trifluoroacetic acid, and perchloric acid; the alkaline solution includes, but is not limited to, at least one of sodium hydroxide and potassium hydroxide. There is no particular limitation on the treatment time with the acid salts or alkaline solution, as long as the aluminum oxide on the surface of the aluminum foil is completely removed.

[0009] Further, in steps (S1) and (S2), the first lithiation reagent and the second lithiation reagent are solutions of aromatic hydrocarbon radical anionic lithium salts, wherein the aromatic hydrocarbons are selected from at least one of naphthalene, anthracene, pyrene, phenanthrene, tetraphenylene, biphenyl, dimethylbiphenyl, and 9,9-dimethylfluorene; the solvent of the aromatic hydrocarbon radical anionic lithium salt solution is selected from at least one of ethylene glycol dimethyl ether, methyl propyl ether, ethylene glycol diethyl ether, tetrahydrofuran, dimethyltetrahydrofuran, and tetrahydropyran; and even further, the concentration of the aromatic hydrocarbon radical anionic lithium salt is 0.5-2 mol / L, preferably 1-1.5 mol / L.

[0010] Furthermore, the aromatic hydrocarbon in the first lithiation reagent is selected from at least one of naphthalene, anthracene, pyrene, phenanthrene, and tetraphenylene. The first lithiation can achieve mild lithiation, avoiding stress concentration or structural damage caused by excessively violent alloying reactions, and forming a uniform LiAl seed layer. The aromatic hydrocarbon in the second pre-lithiation reagent is selected from at least one of biphenyl, dimethylbiphenyl, and 9,9-dimethylfluorene. The second lithiation is a lithiation agent with strong actual reducing properties and good thermal stability. The aromatic hydrocarbon is selected to effectively drive the surface LiAl to transform into the Li9Al4 phase with high ionic conductivity, while ensuring safety and stability under high temperature conditions.

[0011] Further, in step (S1), the low temperature condition is 25-60°C, and the first pre-lithiation time is 5 minutes to 2 hours; preferably, the low temperature condition is 40-50°C, and the first pre-lithiation time is 10 minutes to 30 minutes.

[0012] Further, in step (S2), the high temperature condition is 100-200°C, and the second pre-lithiation time is 1-20 minutes; preferably, the high temperature condition is 120-200°C, and the second pre-lithiation time is 1-6 minutes.

[0013] Furthermore, in step (S2), the lithium-aluminum alloy phase with a higher lithium content includes, but is not limited to, the Li9Al4 phase and Li... 2-x Al phase, 0.5 > x > 0, Li3Al2 phase.

[0014] Further, in step (S3), the solvent used for washing is selected from at least one of ethylene glycol dimethyl ether, methyl propyl ether, ethylene glycol diethyl ether, tetrahydrofuran, dimethyl tetrahydrofuran, and tetrahydropyran, that is, the same solvent used in the above-mentioned aromatic hydrocarbon free radical anion lithium salt solution.

[0015] This invention also provides a fast-charging aluminum anode material prepared by the above method, wherein the Al content increases and the Li content decreases from the inside to the surface. For example, from the inside to the surface, the phases are LiAl phase, Li3Al2 phase, and Li... 2-x Al phase and Li9Al4 phase.

[0016] By adopting the above technical solution, the present invention mainly has the following technical effects: (1) A stepwise lithiation process was adopted to achieve controllable and efficient construction of gradient alloy layers. The core of this invention lies in first forming a uniform and dense LiAl seed layer through low-temperature pre-lithiation, and then performing selective phase transformation through high-temperature secondary lithiation. This design avoids problems such as loose alloy layer, pulverization, or detachment from the current collector caused by the violent reaction during direct high-temperature processing.

[0017] (2) Significantly improved interfacial ion transport kinetics and fast charging performance of aluminum anode. The gradient alloy layer constructed by the above process provides a high-speed channel for ion migration on the surface, which greatly reduces the interfacial impedance; the inner layer effectively retains good toughness and mechanical strength, which together enable the anode to exhibit extremely high capacity retention and excellent rate performance under high current charging conditions.

[0018] (3) It comprehensively balances the contradiction between deep lithiation and volume expansion, and significantly improves cycle stability. The present invention uses a two-step method to precisely control the alloying depth and phase composition, avoiding the huge volume effect caused by deep lithiation of the entire bulk phase. This gradient structure design enables the surface layer to undertake the high-activity fast charging function, while the inner layer acts as a buffer substrate to resist volume changes, thereby effectively solving the common problem of short cycle life of alloy-type anodes without significantly increasing the complexity of the process.

[0019] (4) The preparation method is simple and efficient, and has the potential for large-scale production. The entire process (pretreatment-low temperature lithiation-high temperature lithiation) is smoothly connected, the parameters are easy to control, and the repeatability is good. It does not require complex nanofabrication or expensive equipment and can be realized on a conventional roll-to-roll production line, providing a reliable and efficient solution for the industrial application of high-performance fast-charging aluminum anodes. Attached Figure Description

[0020] Figure 1 Optical photographs of aluminum foil in its original state, in Example 1, and in Comparative Example 1 after low-temperature lithiation and high-temperature lithiation; Figure 2 An optical photograph of the aluminum foil in Comparative Example 2; Figure 3 This is a transmission electron microscope image of the surface lithium-aluminum alloy composition in Example 1; Figure 4 This is a depth profile of lithium secondary ions and aluminum secondary ions in the time-of-flight secondary ion mass spectrometry of the surface lithium-aluminum alloy composition in Example 1. Figure 5 The image shows the X-ray photoelectron spectrum of the aluminum foil in Example 1. Figure 6 The X-ray diffraction pattern of the aluminum foil in Comparative Example 3 is shown. Figure 7 The cycling performance graphs for Example 1 and Comparative Example 3 are shown. Figure 8 Optical photographs of the aluminum foil in Example 2 and Comparative Example 4. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. The embodiments described below are only some embodiments of the present invention and do not represent 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.

[0022] Example 1 (1) Pretreatment: The aluminum foil was placed in a 0.5 mol / L hydrochloric acid solution for 3 min to remove the surface oxide layer, then washed with deionized water and dried in a vacuum oven at 60°C for 6 h; (2) Low-temperature pre-lithiation: The aluminum foil treated in step (1) is placed in 1 mol / L naphthalene lithium-tetrahydrofuran lithiation agent and reacted at 50°C for 10 minutes; (3) High-temperature lithiation: The aluminum foil treated in step (2) is placed in a 1 mol / L biphenyl lithium-tetrahydrofuran lithiation agent and reacted at 200°C for 1 minute; (4) Cleaning and drying: Take out the lithium-ionized aluminum foil, clean it three times with tetrahydrofuran solvent, and dry it at room temperature for 10 minutes to obtain a gradient lithium-aluminum alloy anode.

[0023] Example 2 (1) Pretreatment: The aluminum foil was placed in a 1 mol / L hydrochloric acid solution for 1 min to remove the surface oxide layer, then washed with deionized water and dried in a vacuum oven at 60°C for 6 h. (2) Low-temperature pre-lithiation: The aluminum foil treated in step (1) is placed in 1 mol / L naphthalene lithium-tetrahydrofuran lithiation agent and reacted at 50°C for 20 minutes; (3) High-temperature lithiation: The aluminum foil treated in step (2) is placed in 1 mol / L of biphenyl lithium-tetrahydrofuran lithiation agent and reacted at 120°C for 6 minutes; (4) Cleaning and drying: Take out the lithium-ionized aluminum foil, clean it three times with tetrahydrofuran solvent, and dry it at room temperature for 10 minutes to obtain a gradient lithium-aluminum alloy anode.

[0024] Example 3 (1) Pretreatment: The aluminum foil was placed in a 2 mol / L phosphoric acid solution for 5 h to remove the surface oxide layer, then washed with deionized water and dried in a vacuum oven at 60 °C for 6 h. (2) Low-temperature pre-lithiation: The aluminum foil treated in step (1) is placed in 1 mol / L anthracene lithium-ethylene glycol dimethyl ether lithiation agent and reacted at 50°C for 30 minutes; (3) High-temperature lithiation: The aluminum foil treated in step (2) is placed in 1 mol / L of 9,9-dimethylfluorene lithium-ethylene glycol dimethyl ether lithiation agent and reacted at 120°C for 4 minutes; (4) Cleaning and drying: Take out the lithium-ionized aluminum foil, clean it three times with ethylene glycol dimethyl ether solvent, and dry it at room temperature for 10 minutes to obtain a gradient lithium-aluminum alloy anode.

[0025] Example 4 The other conditions are the same as in Example 1, except that in step (2), the low-temperature pre-lithiation is changed to: placing the aluminum foil treated in step (1) in a 1 mol / L biphenyl lithium-tetrahydrofuran lithifying agent and reacting it at 50°C for 10 minutes. That is, compared with Example 1, both the low-temperature lithiation and high-temperature lithiation in Example 4 are carried out in a biphenyl lithium-tetrahydrofuran lithifying agent.

[0026] Example 5 The other conditions are the same as in Example 1, except that in step (3), the high-temperature pre-lithiation is changed to: placing the aluminum foil treated in step (2) in a 1 mol / L naphthalene lithium-tetrahydrofuran lithifying agent and reacting it at 200°C for 1 minute. That is, compared with Example 1, both the low-temperature lithiation and high-temperature lithiation in Example 5 are carried out in a naphthalene lithium-tetrahydrofuran lithifying agent.

[0027] Example 6 The other conditions are the same as in Example 1, except that step (2) is changed to: placing the aluminum foil treated in step (1) in 1 mol / L lithium biphenyl tetrahydrofuran lithiation agent and reacting it at 50°C for 20 minutes; step (3) is changed to: placing the aluminum foil treated in step (2) in 1 mol / L lithium naphthalene tetrahydrofuran lithiation agent and reacting it at 120°C for 10 minutes. That is, compared with Example 1, the pre-lithiation reagents used in the low-temperature lithiation and high-temperature lithiation of Example 6 are changed.

[0028] Comparative Example 1 (1) Low-temperature pre-lithiation: Place aluminum foil in 1 mol / L naphthalene lithium-tetrahydrofuran lithiation agent and react at 50°C for 10 minutes; (2) High-temperature lithiation: The aluminum foil treated in step (1) is placed in a 1 mol / L biphenyl lithium-tetrahydrofuran lithiation agent and reacted at 200°C for 1 minute; (3) Cleaning and drying: Take out the lithium-ionized aluminum foil, clean it three times with tetrahydrofuran solvent, and dry it at room temperature for 10 minutes to obtain the aluminum anode.

[0029] Comparative Example 2 (1) Pretreatment: The aluminum foil was placed in a 0.5 mol / L hydrochloric acid solution for 3 min to remove the surface oxide layer, then washed with deionized water and dried in a vacuum oven at 60°C for 6 h; (2) High-temperature lithiation: The aluminum foil treated in step (1) is placed in a 1 mol / L biphenyl lithium-tetrahydrofuran lithiation agent and reacted at 200°C for 1 minute; (3) Cleaning and drying: Take out the lithium-ionized aluminum foil, clean it three times with tetrahydrofuran solvent, and dry it at room temperature for 10 minutes to obtain the aluminum anode; (4) Battery assembly: Due to severe damage, it is impossible to assemble it into a lithium-ion battery.

[0030] Comparative Example 3 (1) Pretreatment: The aluminum foil was placed in a 0.5 mol / L hydrochloric acid solution for 3 min to remove the surface oxide layer, then washed with deionized water and dried in a vacuum oven at 60°C for 6 h; (2) Low-temperature pre-lithiation: The aluminum foil treated in step (1) is placed in 1 mol / L naphthalene lithium-tetrahydrofuran lithiation agent and reacted at 50°C for 10 minutes; (3) Cleaning and drying: Take out the lithium-ionized aluminum foil, clean it three times with tetrahydrofuran solvent, and dry it at room temperature for 10 minutes to obtain the aluminum anode.

[0031] Comparative Example 4 (1) Pretreatment: The aluminum foil was placed in a 1 mol / L hydrochloric acid solution for 1 min to remove the surface oxide layer, then washed with deionized water and dried in a vacuum oven at 60°C for 6 h. (2) Low-temperature pre-lithiation: The aluminum foil treated in step (1) is placed in 1 mol / L naphthalene lithium-tetrahydrofuran lithiation agent and reacted at 50°C for 20 minutes; (3) High-temperature lithiation: The aluminum foil treated in step (2) is placed in 1 mol / L of biphenyl lithium-tetrahydrofuran lithiation agent and reacted at 120°C for 15 minutes; (4) Cleaning and drying: Take out the lithium-ionized aluminum foil, clean it three times with tetrahydrofuran solvent, and dry it at room temperature for 10 minutes to obtain the aluminum anode.

[0032] Application examples The aluminum anodes prepared in the above examples and comparative examples are assembled into batteries. The specific steps are as follows: the aluminum anode in (4) is assembled with the lithium cobalt oxide cathode, electrolyte, gasket and spring sheet into a lithium-ion battery. The electrolyte is 1 mol / L lithium hexafluorophosphate (LiPF6) dissolved in DEC / FEC (volume ratio 1:1).

[0033] The lithium-ion batteries assembled with aluminum anodes prepared in the above embodiments and comparative examples were tested at room temperature with a current density of 3C (1C = 160 mA / g) (wherein, only Example 2 had 1C = 160 mA / g and a cutoff voltage of 2.3-3.5V, while the other application examples had 1C = 180 mA / g and a cutoff voltage of 2.8-4.2V). The results are shown in Table 1 below: Table 1. Lithium-ion battery performance test .

[0034] Based on the comparative experimental results of the examples and comparative examples, the following conclusions can be drawn: (1) It is demonstrated that surface pretreatment is an indispensable prerequisite for achieving effective chemical prelithiation. Figure 1 This indicates that the untreated aluminum foil in Comparative Example 1, due to the presence of an alumina barrier on its surface, cannot effectively react with the lithiation agent at low temperatures. While high-temperature treatment alone can partially overcome this barrier, the reaction is violent and uncontrollable, resulting in an uneven alloy layer and poor adhesion. Example 1 confirms that only by thoroughly removing the oxide layer through pretreatment can a foundation be laid for a uniform and controllable subsequent lithiation reaction.

[0035] (2) It reveals that the key role of the “low temperature pre-lithiation” step is to form a strong seed layer and ensure structural integrity. Figure 2 This indicates that, as shown in Comparative Example 2, if the low-temperature pre-lithiation step is skipped, even with pretreatment, the aluminum foil will curl and break during direct high-temperature lithiation due to the instantaneous and intense alloying reaction and stress. Example 1 demonstrates that the uniform and dense LiAl seed layer formed by room-temperature pre-lithiation not only induces the uniformity of the subsequent high-temperature reaction but also serves as an important buffer layer, effectively releasing the internal stress generated by high-temperature lithiation, thereby ensuring the structural integrity and flatness of the electrode after high-temperature treatment.

[0036] (3) The decisive contribution of the "high temperature secondary lithiation" step to improving fast charging performance was clarified. Figure 3 It was confirmed that the outermost alloy phase of the aluminum foil prepared in Example 1 was Li9Al4. Figure 4 This confirms that a gradient-distributed lithium-aluminum alloy layer was successfully constructed on the aluminum foil surface in Example 1. After 400 s of etching, the relative strength of Li decreased by 36.96%, while the relative strength of Al increased by 18.02%. Further XPS analysis of the aluminum foil in Example 1 yielded the following results: Figure 5 As shown, the gradient distribution of the lithium-aluminum alloy indicates that from the surface to the interior, the phases are Li9Al4, Li... 2-x Al phase, Li3Al2 phase, LiAl phase. Figure 6 This indicates that the aluminum foil in Comparative Example 3, which did not undergo high-temperature lithiation, only contained LiAl and Al. For example... Figure 7As shown, the electrode obtained by only performing room temperature pre-lithiation in Comparative Example 3 exhibits poor high-current (fast charging) performance. This is because its surface is mainly composed of the LiAl phase, which has relatively low ionic conductivity. Example 1 demonstrates that high-temperature short-time treatment is a key step in promoting the transformation of the surface LiAl phase to a phase with higher ionic conductivity, thereby significantly improving the rate performance and fast charging capability of the negative electrode.

[0037] (4) The process window for precise control of high-temperature treatment time was established. Figure 8 This indicates that, as in Comparative Example 4, an excessively long high-temperature lithiation time can lead to an excessively thick alloy layer and excessive internal stress accumulation, which can also damage the structural integrity of the negative electrode. This contrasts with the results of Examples 1 and 2, demonstrating that the short-time high-temperature treatment described in this invention is an optimized process window that can both achieve surface phase transformation to optimize performance and strictly guarantee product yield.

[0038] (5) This invention not only clarifies that stepwise pre-lithiation, i.e., first low-temperature pre-lithiation followed by high-temperature pre-lithiation, can yield aluminum anodes with excellent electrochemical performance, but also determines the optimal scheme for the lithiation reagents used in the first low-temperature pre-lithiation and the second high-temperature pre-lithiation. The low-temperature pre-lithiation selects a pre-lithiation reagent with mild activity and a relatively long lithiation time; the second pre-lithiation selects a lithiation reagent with high activity and high temperature resistance and a relatively short lithiation time. This operation ensures that the surface layer can be rapidly, uniformly, and controllably transformed into a high ionic conductivity phase in the subsequent high-temperature stage, while the inner layer maintains the buffer structure of the LiAl phase, thereby precisely constructing a gradient distribution with optimal performance.

[0039] In summary, this invention achieves a balance between fast charging performance and structural stability by employing a multi-step synergistic process of pretreatment, low-temperature lithiation, and high-temperature lithiation, which addresses multiple challenges such as surface oxidation barrier, reaction intensity, and phase composition control.

Claims

1. A method for preparing a fast-charging aluminum anode material based on stepped-temperature lithiation, characterized in that, Includes the following steps: (S1) The aluminum foil with the surface oxide layer removed is placed in the first lithiation reagent, and under low temperature conditions, a LiAl phase is formed on the surface of the aluminum foil to obtain the first pre-lithiation aluminum foil; (S2) The aluminum foil that has been pre-lithiated for the first time is placed in the second lithiation reagent. Under high temperature conditions, the LiAl phase is partially transformed into a lithium-aluminum alloy phase with a higher lithium content, thus obtaining the aluminum foil that has been pre-lithiated for the second time. (S3) The aluminum foil pre-lithiated for the second time is washed and dried to obtain the fast-charging aluminum anode material.

2. The preparation method according to claim 1, characterized in that, The first and second lithiation reagents are solutions of aromatic hydrocarbon radical anionic lithium salts, wherein the aromatic hydrocarbons are selected from at least one of naphthalene, anthracene, pyrene, phenanthrene, tetraphenylene, biphenyl, dimethylbiphenyl, and 9,9-dimethylfluorene; and the solvent of the aromatic hydrocarbon radical anionic lithium salt solution is selected from at least one of ethylene glycol dimethyl ether, methyl propyl ether, ethylene glycol diethyl ether, tetrahydrofuran, dimethyltetrahydrofuran, and tetrahydropyran.

3. The preparation method according to claim 2, characterized in that, The concentration of the aromatic hydrocarbon radical anionic lithium salt is 0.5-2 mol / L, preferably 1-1.5 mol / L.

4. The preparation method according to claim 2, characterized in that, The aromatic hydrocarbon of the first lithiation reagent is selected from at least one of naphthalene, anthracene, pyrene, phenanthrene, and tetraphenylene; the aromatic hydrocarbon of the second prelithiation reagent is selected from at least one of biphenyl, dimethylbiphenyl, and 9,9-dimethylfluorene.

5. The preparation method according to claim 1, characterized in that, In step (S1), the low temperature condition is 25-60°C, and the first pre-lithiation time is 5 minutes to 2 hours; preferably, the low temperature condition is 40-50°C, and the first pre-lithiation time is 10 minutes to 30 minutes.

6. The preparation method according to claim 1, characterized in that, In step (S2), the high temperature condition is 100-200℃, and the second pre-lithiation time is 1-20 minutes; preferably, the high temperature condition is 120-200℃, and the second pre-lithiation time is 1-6 minutes.

7. The preparation method according to claim 1, characterized in that, In step (S2), the lithium-aluminum alloy phase with higher lithium content includes, but is not limited to, Li9Al4 phase, Li 2-x Al phase, 0.5 > x > 0, Li3Al2 phase.

8. The preparation method according to claim 1, characterized in that, In step (S3), the solvent used for washing is selected from at least one of ethylene glycol dimethyl ether, methyl propyl ether, ethylene glycol diethyl ether, tetrahydrofuran, dimethyl tetrahydrofuran, and tetrahydropyran.

9. A fast-charging aluminum anode material, prepared by the preparation method according to any one of claims 1-8, wherein the Al content increases and the Li content decreases from the interior to the surface of the fast-charging aluminum anode material.

10. A lithium-ion battery, comprising a positive electrode, a negative electrode, and an electrolyte, characterized in that, The negative electrode is a fast-charging aluminum negative electrode material prepared by the preparation method according to any one of claims 1-8.

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