Preparation process of multi-element halogenated MXene / carbon fiber metal lithium negative electrode
By employing acidification pretreatment and multi-element halogenation heat treatment, the problems of weak interfacial bonding and inaccurate lithium-ion deposition behavior of MXene and carbon fiber composite materials in lithium metal anodes were solved, achieving a stable composite framework and uniform lithium deposition, improving the cycle stability and safety of the electrode, and making it suitable for high-energy-density lithium secondary batteries.
Patent Information
- Application Number
- CN202610591501.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-04-30
- Publication Date
- 2026-06-23
AI Technical Summary
In existing technologies, MXene and carbon fiber composite materials in lithium metal anodes suffer from weak interfacial bonding, imprecise control of lithium-ion deposition behavior, and cumbersome preparation processes, leading to easy damage to the electrode structure, severe lithium dendrite growth, and poor battery safety.
By acidifying and pretreating carbon fibers to introduce oxygen-containing functional groups, and then combining them with MXene colloidal dispersion, followed by heat treatment under a protective atmosphere to perform multi-halogenation, a stable multi-halogen terminal is formed, realizing the chemical bonding between MXene and carbon fibers. Finally, a multi-halogenated MXene/carbon fiber composite skeleton is formed by loading lithium metal.
It achieves a stable combination of MXene and carbon fiber, precisely controls lithium-ion deposition behavior, suppresses lithium dendrite growth, and improves the cycle stability and safety of the electrode, making it suitable for high-energy-density lithium secondary batteries.
Abstract
Description
Technical Field
[0001] This application relates to the field of electrochemical energy storage technology, and more specifically, it relates to a process for preparing a multi-component halide MXenes / carbon fiber lithium metal anode. Background Technology
[0002] With the rapid development of electric vehicles, portable electronic devices and large-scale energy storage systems, the market demand for high-energy-density and high-safety secondary batteries is becoming increasingly urgent. Due to its extremely high theoretical specific capacity and the lowest electrode potential, lithium metal anode is considered to be the ideal anode material for the next generation of high-energy-density lithium batteries.
[0003] However, lithium metal anodes face numerous technical challenges in practical applications. First, upon contact with the electrolyte, lithium metal easily forms an unstable solid-state electrolyte interface (SEI) film. This film repeatedly breaks and reconstructs during lithium deposition / stripping, leading to continuous electrolyte consumption and shortened battery cycle life. Second, uneven deposition of lithium ions on the anode surface during charging and discharging easily forms sharp lithium dendrites. Dendrite growth can pierce the separator, causing internal short circuits and posing serious safety hazards. Furthermore, lithium metal lacks stable skeletal support during deposition / stripping, resulting in significant volume expansion and electrode structure pulverization, further exacerbating SEI film rupture and dendrite growth problems.
[0004] To address these challenges, researchers have proposed a strategy of constructing a three-dimensional conductive framework to load lithium metal. MXenes, as novel two-dimensional transition metal carbide / nitride materials, possess excellent conductivity, abundant surface functional groups, and good mechanical strength, and have been widely studied as lithium metal host materials. Carbon fibers, with their high conductivity, lightweight, and three-dimensional network structure, can serve as an ideal structural framework. Existing technologies have reported the construction of three-dimensional frameworks by combining MXenes with carbon fibers, for example, by loading MXenes onto the carbon fiber surface through physical mixing or simple coating methods, and then introducing lithium metal through electrodeposition or melt infusion.
[0005] However, the aforementioned existing technical solutions still have significant drawbacks. First, existing technologies mostly employ physical adsorption to attach MXene nanosheets to the carbon fiber surface, resulting in a lack of chemical bonding between the two. During long-term cycling, repeated expansion and contraction cause MXene to easily detach from the carbon fiber surface, leading to damage to the conductive network and electrode structure failure. Second, the surface functional groups of MXene prepared by conventional methods are mainly -F and -OH, which have weak affinity for lithium ions and uneven surface energy distribution, making it impossible to effectively control lithium ion deposition behavior. MXene with single functional groups is difficult to precisely regulate the lithium nucleation overpotential and has limited inhibitory effect on dendrite growth. Third, to achieve effective composite formation of MXene and carbon fiber and control of surface properties, existing technologies often require multi-step reactions and complex post-processing, which are cumbersome, time-consuming, and unfavorable for large-scale production. Summary of the Invention
[0006] To overcome the shortcomings of existing MXenes / carbon fiber composite lithium metal anode materials, such as weak interfacial bonding, imprecise control of lithium-ion deposition behavior, and cumbersome and costly preparation processes, this application provides a preparation process for multi-element halide MXenes / carbon fiber lithium metal anodes.
[0007] Firstly, this application provides a preparation process for a multi-component halide MXenes / carbon fiber lithium metal anode, employing the following technical solution: A process for preparing a multi-component halide MXenes / carbon fiber lithium metal anode includes the following steps: Acidification pretreatment is performed on carbon fibers to introduce oxygen-containing functional groups on the surface of the carbon fibers, thus obtaining acidified carbon fibers. Preparation of MXene colloidal dispersion; Acidified carbon fibers were impregnated in MXene colloidal dispersion to allow MXene nanosheets to adsorb onto the carbon fiber surface, thus obtaining a composite precursor. The composite precursor and a halide source were then heat-treated under a protective atmosphere to perform multi-component halogenation of MXene and bonding between MXene and carbon fibers, thereby obtaining a multi-component halogenated MXene / carbon fiber composite framework. A lithium metal anode was prepared by loading a multi-component MXene / carbon fiber composite skeleton with lithium metal.
[0008] By employing the above technical solution, carbon fibers are first pretreated with acidification to introduce oxygen-containing functional groups, such as -COOH and -OH, onto their surface, enhancing their hydrophilicity and reactivity and providing reaction sites for subsequent chemical bonding with MXene. The pretreated carbon fibers are then impregnated in an MXene colloidal dispersion, allowing MXene nanosheets to initially adsorb onto the carbon fiber surface via electrostatic interactions or hydrogen bonding, forming a composite precursor. The composite precursor and a halide source are then heat-treated under a protective atmosphere. This step serves a dual purpose: firstly, the heat drives a displacement reaction between some -F / -OH functional groups on the MXene surface and the halogen source, forming uniform -Cl, -Br, and -I multi-halogen terminals on the MXene surface and edges; secondly, this heat treatment process promotes a chemical reaction between the MXene nanosheets and the oxygen-containing functional groups on the activated carbon fiber surface, achieving in-situ strong interfacial composite bonding and solving the problem of weak interfacial bonding in traditional physical adsorption methods. Finally, the obtained multi-halogenated MXene / carbon fiber composite framework is used as a host, and lithium metal is loaded onto it to introduce lithium metal into its three-dimensional porous structure, thus preparing a lithium metal anode. Multi-halogen terminals, through the differences in electronegativity and ionic radius of different halogens, synergistically regulate the adsorption energy and diffusion barrier of lithium ions, inducing lithium to preferentially nucleate and grow uniformly between MXene sheets and at carbon fiber network nodes, forming a dendrite-free dense lithium deposition layer, thereby significantly improving the cycle stability and safety of the anode.
[0009] Preferably, the halide source is one or a mixture of ammonium iodide, ammonium bromide, zinc chloride, lithium iodide, and potassium bromide.
[0010] By adopting the above technical solutions, the halide sources can release corresponding halide ions or halogen gases under heat treatment conditions, which can then undergo displacement reactions with the -F and -OH functional groups on the MXene surface. By using a mixture of multiple halide sources, multiple halogen terminals can be introduced simultaneously onto the MXene surface, forming a surface chemical environment for multi-halogen synergistic modification. Ammonium salt halides decompose under heating conditions to produce hydrogen halide gas, which is beneficial for the uniformity of gas-phase halogenation reactions. Alkali metal or transition metal halides can achieve solid-phase halogenation through the molten salt pathway. The combined use of multiple halide sources allows for flexible control of the type, ratio, and distribution of halogen terminals on the MXene surface, enabling precise control of lithium deposition behavior.
[0011] Preferably, the heat treatment temperature is 200-450℃.
[0012] By employing the above technical solution, the heat treatment temperature is controlled within the range of 200-450℃. This effectively drives the halogenation substitution reaction, allowing the functional groups on the MXene surface to fully react with the halogen source and form stable multi-halogen terminals. Simultaneously, it avoids excessively high temperatures that could lead to MXene oxidation or a decrease in the mechanical properties of the carbon fiber. Furthermore, this temperature range is conducive to chemical bonding reactions (such as esterification and ether bond formation) between MXene and oxygen-containing functional groups on the carbon fiber surface, forming strong chemical bonds such as CO-Ti, achieving a stable interfacial bond. Too low a temperature results in an incomplete reaction, while too high a temperature may damage the material structure. Therefore, this temperature range is the preferred range that balances reaction efficiency and material structural stability.
[0013] Preferably, the MXenes are Ti3C2T. x T x It is a -OH group or a -F group.
[0014] By adopting the above technical solution, Ti3C2T x It is one of the most mature and stable MXene materials in terms of research and preparation process. Its precursor, Ti3AlC2MAX phase, is easy to obtain, and the etching process is mature. Ti3C2T x The surface is rich in -OH and -F functional groups, providing ample active sites for subsequent multi-component halogenation substitution reactions. Furthermore, Ti3C2T x It possesses excellent electrical conductivity and mechanical strength, and when used as a lithium metal host material, it can provide a good electron transport channel and structural support, which is beneficial for achieving uniform lithium deposition.
[0015] Preferably, the loaded lithium metal treatment is performed by electrochemical deposition or molten lithium infusion.
[0016] By employing the above-mentioned technical solutions, the electrochemical deposition method can precisely control the deposition amount and distribution morphology of metallic lithium in the composite framework by controlling the current density, deposition time, and electrolyte composition. This method is simple to operate and operates under mild conditions. The molten lithium infusion method utilizes capillary forces to draw molten metallic lithium into the three-dimensional porous structure of the composite framework, achieving efficient and rapid lithium loading, and is particularly suitable for large-scale preparation. Both methods are well-suited to the composite framework structure, enabling efficient filling of metallic lithium within the framework and forming a dense, dendrite-free lithium deposition layer.
[0017] Preferably, the surface of the multi-halogenated MXene / carbon fiber composite skeleton contains at least two halogen terminals selected from -Cl, -Br, and -I.
[0018] By adopting the above technical solution, the combination of multiple halogen terminals forms a gradient distribution of chemical energy on the MXene surface. Different halogens have different electronegativity and ionic radii, and their binding energy for lithium ions varies. When multiple halogens coexist, a synergistic regulation effect of local electric field and adsorption energy can be formed on the MXene surface, inducing lithium ions to preferentially nucleate at specific active sites, avoiding dendrite growth caused by local current concentration. The introduction of multiple halogen terminals changes the polarity and wettability of the MXene surface, which is conducive to uniform wetting of electrolyte and rapid transport of lithium ions, thereby improving the rate performance and cycle stability of the battery.
[0019] Secondly, this application provides a multi-component halide MXenes / carbon fiber lithium metal anode, employing the following technical solution: A multi-component MXene / carbon fiber lithium metal anode is prepared by a multi-component MXene / carbon fiber lithium metal anode preparation process, comprising a multi-component MXene / carbon fiber composite framework and lithium metal filling the pores therein.
[0020] By adopting the above technical solution, the lithium metal anode uses a multi-halogenated MXene / carbon fiber composite framework as the supporting structure, combining the high specific surface area and excellent conductivity of two-dimensional MXene materials with the structural stability of three-dimensional carbon fiber framework. Multi-halogenation modification endows the MXene surface with the ability to regulate lithium deposition behavior, and the chemical bonding interface ensures the structural integrity of the framework during cycling. Lithium metal is uniformly filled in the pores of the framework, effectively suppressing lithium dendrite growth and volume expansion. This anode has high coulombic efficiency, long cycle life and excellent safety performance.
[0021] Thirdly, this application provides a lithium secondary battery, which adopts the following technical solution: A lithium secondary battery comprising a positive electrode, an electrolyte, a separator, and the multi-component halogenated MXenes / carbon fiber lithium metal anode as described in claim 7.
[0022] By adopting the above technical solution, the lithium secondary battery containing the above-mentioned lithium metal anode exhibits excellent capacity retention and cycle stability during charge and discharge cycles. The anode structure is stable and has good interface compatibility, effectively suppressing lithium dendrite growth, reducing the risk of internal short circuits in the battery, and significantly improving the battery's safety performance. It is suitable for applications with high energy density and high safety requirements, such as electric vehicles, portable electronic devices, and large-scale energy storage systems.
[0023] In summary, this application has the following beneficial effects: 1. Because this application adopts a sequentially controllable "adsorption-halogenation-bonding" integrated process, after MXene is initially attached to carbon fiber, multi-element halogenation modification and interfacial chemical bonding are achieved simultaneously through one-step heat treatment. The steps are simplified and the conditions are mild. At the same time, it overcomes the problems of weak interfacial bonding and complicated processes in the prior art, and has the potential for large-scale production. Through the chemical bonding of MXene with the functional groups on the surface of carbon fiber during the heat treatment process, the two-dimensional MXene and one-dimensional carbon fiber are stably integrated, avoiding the problem of MXene falling off during cycling and ensuring the long-term mechanical integrity of the electrode structure.
[0024] 2. In this application, multi-halogen modification is preferred, introducing at least two of the halogen terminals -Cl, -Br, and -I on the MXene surface. By utilizing the differences in electronegativity and ionic radius of different halogens, the adsorption energy and diffusion barrier of lithium ions are synergistically controlled. The multi-halogen terminals form a gradient distribution of chemical energy on the MXene surface, inducing lithium ions to preferentially nucleate uniformly between MXene layers and at carbon fiber network nodes, thereby achieving dendrite-free dense lithium deposition and effectively solving the problem of imprecise control of lithium deposition behavior in the prior art.
[0025] 3. The method of this application introduces oxygen-containing functional groups on the carbon fiber surface through acidification pretreatment, providing reaction sites for subsequent chemical bonding; achieves uniform distribution of MXene on the carbon fiber surface through impregnation adsorption; simultaneously completes multi-component halogenation modification and interfacial bonding through heat treatment; and obtains the final anode product through lithium metal loading treatment. The synergistic effect of each step forms a complete technology chain from framework construction to surface modification to lithium loading. The lithium metal anode prepared by this method is significantly superior to the prior art in terms of cycle stability, coulombic efficiency and safety. The lithium secondary battery containing this anode has high energy density and long cycle life, and is suitable for a variety of demanding application scenarios. Detailed Implementation
[0026] The present application will be further described in detail below with reference to the embodiments. Example
[0027] Example 1 A process for preparing a multi-component halide MXenes / carbon fiber lithium metal anode includes the following steps: Carbon fiber cloth was cut into 5cm×5cm pieces, ultrasonically cleaned in acetone for 30 minutes to remove surface contaminants, washed with deionized water and dried. The cleaned carbon fiber cloth was then immersed in a mixed acid solution of 98% concentrated sulfuric acid and 68% concentrated nitric acid (volume ratio 3:1) and acidified in a 60℃ water bath for 2 hours. After treatment, it was washed with a large amount of deionized water until the pH value was close to neutral, and then vacuum dried at 60℃ for 12 hours to obtain acidified carbon fiber with oxygen-containing functional groups introduced on the surface. Take 2g of Ti3AlC2MAX phase powder, add 20mL of 40% hydrofluoric acid solution, and etch in a 40℃ water bath with stirring for 24h. The etched product is washed repeatedly by centrifugation with deionized water until the pH of the supernatant is 6. The resulting multilayer Ti3C2T x MXene precipitate was dispersed in 50 mL of deionized water, and 1 mL of dimethyl sulfoxide was added as an intercalating agent. The mixture was stirred for 12 h, followed by sonication in an ice bath for 60 min under nitrogen protection. After sonication, the mixture was centrifuged at 2000 rpm for 10 min, and the supernatant was collected to obtain Ti3C2T with a concentration of 2.5 mg / mL. x MXene colloidal dispersion, stored at 4°C for later use; Take the obtained Ti3C2T x 100 mL of MXene colloidal dispersion was used to immerse the acidified carbon fiber cloth in it and let it stand at room temperature for 12 h to allow the MXene nanosheets to be fully adsorbed onto the carbon fiber surface. After removal, it was vacuum dried at 60 °C for 6 h to obtain the composite precursor. The composite precursor was placed in a tube furnace. Ammonium iodide and zinc chloride were mixed at a mass ratio of 2:1 as a halide source. 1g of the halide source was weighed and placed in the upstream of the furnace. Argon gas was introduced for protection. The furnace was heated to 350℃ at a heating rate of 5℃ / min and held for 4h. After natural cooling, the multi-halogenated MXene / carbon fiber composite skeleton was obtained. The molten lithium infusion method was used to heat metallic lithium to 200°C in an argon glove box to melt it. The multi-halogenated MXene / carbon fiber composite skeleton was immersed in the molten lithium, and the metallic lithium was filled into the pores of the skeleton by capillary action. After holding for 10 minutes, it was taken out and naturally cooled to obtain the multi-halogenated MXenes / carbon fiber metallic lithium anode.
[0028] Example 2
[0029] The difference between Example 2 and Example 1 is that in Example 2, the halide source is a mixture of ammonium bromide and lithium iodide in a mass ratio of 1:1, the heat treatment temperature is 300℃, and the holding time is 3h. Lithium metal was loaded using an electrochemical deposition method. A composite framework was used as the working electrode and a lithium metal sheet was used as the counter electrode. The lithium metal anode was prepared by constant current deposition at a current density of 1 mA / cm² for 4 h in a 1 mol / L LiTFSI / DOL-DME electrolyte.
[0030] Example 3
[0031] The difference between Example 3 and Example 1 is that in Example 3, the halide source is a mixture of zinc chloride and potassium bromide in a mass ratio of 1:2, the heat treatment temperature is 400℃, and the holding time is 2h. Comparative Example
[0032] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, the composite precursor is not heat-treated with the halide source, but is directly used to load lithium metal. That is, the composite precursor is directly loaded with lithium metal by the molten lithium infusion method to obtain the lithium metal anode.
[0033] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, the halide source is only zinc chloride.
[0034] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that in Comparative Example 3, no carbon fiber skeleton is used. Instead, the MXene colloidal dispersion prepared in Example 1 is vacuum filtered to form a film, dried, and then directly used as the host material. Metallic lithium is loaded by the molten lithium infusion method to obtain a metallic lithium anode. Performance testing
[0035] The following performance tests were performed on the lithium metal anodes prepared in Examples 1-3 and Comparative Examples 1-3, and the results are recorded in Table 1: 1. Coulomb efficiency test Reference standard: SJ / T 11793-2022 "Test Methods for Electrochemical Performance of Lithium-ion Battery Electrode Materials"; Test conditions: Current density 1 mA / cm² 2 Deposition / stripping capacity 1mAh / cm 2 Cutoff potential 0-1.0V (vs Li / Li) + Record the initial coulomb efficiency and the cyclic coulomb efficiency; 2. Long-cycle stability test Reference standard: SJ / T 11793-2022 "Test Methods for Electrochemical Performance of Lithium-ion Battery Electrode Materials"; Test conditions: Current density 1 mA / cm² 2 Deposition / stripping capacity 1mAh / cm 2 Record the number of cycles when the capacity retention rate decays to 80%; 3. Evaluation of lithium dendrite suppression Reference method: SJ / T 11793-2022 "Test Method for Electrochemical Performance of Lithium-ion Battery Electrode Materials"; Test conditions: at 1 mA / cm 2 After cycling at current density for 100 cycles, the battery was disassembled and the surface morphology of the negative electrode was observed using a scanning electron microscope (SEM). 4. Interface impedance test Reference standard: SJ / T 11793-2022 "Test Methods for Electrochemical Performance of Lithium-ion Battery Electrode Materials"; Test conditions: Frequency range 10 6 -10 -2Hz, AC disturbance signal amplitude 5mV, R_SEI and R_CT are obtained by equivalent circuit fitting; 5. Ratio Performance Test Reference standard: SJ / T 11793-2022 "Test Methods for Electrochemical Performance of Lithium-ion Battery Electrode Materials"; Test conditions: at 4 mA / cm 2 Charge-discharge tests were conducted at a current density of 0.5 mA / cm². 2 The capacity retention rate is calculated based on the lower capacity. 6. Negative electrode structure stability test Reference method: SJ / T 11793-2022 "Test Method for Electrochemical Performance of Electrode Materials for Lithium-ion Batteries"; Test conditions: Measure the electrode thickness after 100 cycles, and calculate the volume expansion rate: d = (thickness after cycling - original thickness) / original thickness × 100%.
[0036] Table 1 Performance Tests of Lithium Metal Anodes project First Coulomb efficiency / % Cyclic coulomb efficiency / % Cycle life / cycles Surface morphology description R_SEI / Ω R_CT / Ω Capacity retention rate / % Volume expansion rate / % Example 1 92.6 98.7 850 The surface is dense and smooth, without dendrites. 12.5 18.3 89.3 17.1 Example 2 91.8 98.2 780 The surface is dense and smooth, without dendrites. 13.8 19.6 88.1 19.3 Example 3 92.1 98.5 820 The surface is dense and smooth, without dendrites. 13.1 19.2 88.7 17.9 Comparative Example 1 85.6 92.3 210 The surface is porous and contains obvious dendrites. 28.6 45.2 72.6 38.5 Comparative Example 2 88.7 95.1 380 The surface is relatively smooth, with small dendrites present in some areas. 19.5 32.8 79.3 28.0 Comparative Example 3 82.1 88.6 120 The surface is severely powdery and contains a large number of dendrites. 35.2 58.5 62.4 48.3 As can be seen from Table 1, Examples 1-3 and Comparative Examples 1-3, the multi-component halide MXenes / carbon fiber lithium metal anodes prepared in Examples 1-3 have excellent coulombic efficiency, ultra-long cycle life and excellent structural stability, which can effectively suppress lithium dendrite growth and significantly improve the electrochemical performance and safety performance of lithium metal anodes.
[0037] The preparation process in Examples 1-3 successfully introduced multi-halogen terminals onto the MXene surface through an integrated "adsorption-halogenation-bonding" strategy, achieving chemical bonding between MXene and the carbon fiber skeleton. The multi-halogen terminals, such as -Cl, -Br, and -I, synergistically modulated the adsorption energy and diffusion barrier of lithium ions through the differences in electronegativity and ionic radius of different halogens. This induced uniform nucleation of lithium ions between MXene sheets and at carbon fiber network nodes, forming a dense and flat lithium deposition layer, thereby significantly improving the initial coulombic efficiency and cycle coulombic efficiency. Secondly, the chemically bonded interface ensured the mechanical integrity of the composite skeleton during long-term cycling, effectively buffering the volume expansion of metallic lithium. This resulted in a volume expansion rate after 100 cycles that was far lower than the comparative example, providing a structural basis for the long lifespan of the electrode. The stable conductive network and excellent interfacial compatibility reduced interfacial impedance, promoting rapid lithium ion transport, thus achieving excellent rate performance at high current densities.
[0038] Compared with Example 1, Comparative Example 1 showed significantly inferior performance in terms of initial coulombic efficiency, cycle life, and volume expansion rate. The composite precursor of Comparative Example 1 was used directly to load lithium metal without undergoing heat treatment and halogenation modification. This indicates that the "halogenation-bonding" step was missing. On the one hand, the MXene surface was still dominated by -F and -OH functional groups, which had a weak affinity for lithium ions and were unevenly distributed, making it impossible to effectively control lithium deposition behavior, resulting in severe dendrite growth. On the other hand, the MXene and carbon fiber were only physically adsorbed and bonded, resulting in weak interfacial bonding. During cycling, the MXene was easily detached, leading to damage to the conductive network and failure of the electrode structure, thereby significantly shortening the cycle life and exacerbating the volume expansion.
[0039] Compared to Example 1, Comparative Example 2 showed a decrease in cycle life, interfacial impedance, and dendrite suppression effect. Comparative Example 2 used only a single halide source for heat treatment. This indicates that, compared to Example 1 which used multiple halide sources, a single halogen terminal cannot form a chemical energy gradient distribution on the MXene surface, has limited ability to regulate lithium deposition behavior, and local current concentration and fine dendrites may still occur. Therefore, its effect on suppressing dendrites and stabilizing the interface is not as good as Example 1 with multi-halogen synergistic modification.
[0040] Compared to Example 1, Comparative Example 3 exhibited the worst performance in terms of initial coulombic efficiency, cycle life, and volume expansion rate. Comparative Example 3 did not use a carbon fiber skeleton, relying solely on an MXene film as the host. This demonstrates that relying solely on two-dimensional MXene materials, lacking the macroscopic structural support of a three-dimensional carbon fiber skeleton, cannot effectively mitigate the significant volume changes during lithium metal deposition / stripping. The electrode is prone to pulverization during cycling, leading to repeated SEI film rupture and regeneration, continuous electrolyte consumption, a rapid decline in coulombic efficiency, and an extremely short cycle life. This proves the necessity of constructing a three-dimensional skeleton using a composite of MXene and carbon fiber in this application.
[0041] In summary, this application achieves precise control of lithium metal deposition behavior and long-term stability of electrode structure by constructing a multi-component halogenated MXene / carbon fiber composite framework and utilizing an integrated "adsorption-halogenation-bonding" process. Its comprehensive performance is significantly better than comparative schemes that do not undergo multi-component halogenation modification, only undergo single halogenation modification, or do not use a carbon fiber framework.
[0042] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.
Claims
1. A process for preparing a multi-component halide MXenes / carbon fiber lithium metal anode, characterized in that: Includes the following steps: Acidification pretreatment is performed on carbon fibers to introduce oxygen-containing functional groups on the surface of the carbon fibers, thus obtaining acidified carbon fibers. Preparation of MXene colloidal dispersion; Acidified carbon fibers were impregnated in MXene colloidal dispersion, allowing MXene nanosheets to adsorb onto the carbon fiber surface, thus obtaining a composite precursor. The composite precursor and halide source were heat-treated under a protective atmosphere to perform multi-component halogenation of MXene and bonding between MXene and carbon fiber, thus obtaining a multi-component halogenated MXene / carbon fiber composite skeleton. A lithium metal anode was prepared by loading a multi-component MXene / carbon fiber composite skeleton with lithium metal.
2. The preparation process of a multi-component halide MXenes / carbon fiber lithium metal anode according to claim 1, characterized in that: The halide source is one or more of ammonium iodide, ammonium bromide, zinc chloride, lithium iodide, and potassium bromide.
3. The preparation process of a multi-component halide MXenes / carbon fiber lithium metal anode according to claim 1, characterized in that: The heat treatment temperature is 200-450℃.
4. The preparation process of a multi-component halide MXenes / carbon fiber lithium metal anode according to claim 1, characterized in that: The MXenes are Ti3C2T x T x It is a -OH group or a -F group.
5. The preparation process of a multi-component halide MXenes / carbon fiber lithium metal anode according to claim 1, characterized in that: The loaded lithium metal treatment is performed by electrochemical deposition or molten lithium infusion.
6. The preparation process of a multi-component halide MXenes / carbon fiber lithium metal anode according to claim 1, characterized in that: The surface of the multi-halogenated MXene / carbon fiber composite skeleton contains at least two halogen terminals selected from -Cl, -Br, and -I.
7. A multi-component halide MXenes / carbon fiber lithium metal anode, characterized in that: The lithium metal anode is prepared by any one of the following methods: a multi-component halogenated MXenes / carbon fiber composite framework and lithium metal filling the pores therein.
8. A lithium secondary battery, characterized in that: It comprises a positive electrode, an electrolyte, a separator, and the multi-halogenated MXenes / carbon fiber lithium metal anode as described in claim 7.