Molybdenum-based current collector composite material, integrated electrode and preparation method and application thereof

Abstract

The invention provides a molybdenum-based current collector composite material, an integrated electrode and a preparation method and application of the integrated electrode. According to the preparation method, commercial carbon cloth is modified by adopting a transition metal compound, namely molybdenum-based oxide / nitride, so that the molybdenum functionalized carbon cloth current collector is prepared; the current collector achieves excellent structural, chemical, electrical, mechanical and thermal stability as well as excellent electrode compatibility. The invention also comprises the step of preparing an integrated electrode by growing a plurality of active materials on the molybdenum functionalized current collector. The integrated electrode exhibits extremely high efficiency in sodium ion batteries (NIBs), potassium ion batteries (KIBs), zinc ion batteries (ZIBs), and hydrogen evolution reactions (HER) and oxygen evolution reactions (OER). The unique functional treatment and electrode preparation process optimizes charge transfer, reduces interface impedance, and significantly improves the durability of the device, so that the device has broad prospects in electrochemical energy storage and conversion application.

Description

Technical Field

[0001] The present invention relates to the technical field of current collector and electrode preparation, and in particular to a molybdenum-based current collector composite material, an integrated electrode, and a preparation method and application thereof. Background Art

[0002] The properties of current collectors are crucial to the performance and safety of electrochemical devices, and their selection is particularly critical in systems such as metal-ion batteries [Adv. Funct. Mater. 2023, 33, 2305515], supercapacitors [Energy Environ. Sci., 2016, 9, 2847-2854], and water splitting [Adv. Energy Mater., 2020, 10(24), 1904020.]. Current collectors have two main functions: (i) facilitating the transport of electrons to the external circuit; and (ii) providing mechanical support as a conductive substrate for the deposition of active materials [Adv. Mater. 2018, 30, 1802014]. Since the commercialization of lithium-ion batteries (LIBs), aluminum (Al) and copper (Cu) foils have been the standard choices for positive and negative current collectors, respectively. However, with the development of research, other metals such as nickel (Ni), titanium (Ti), stainless steel, and non-metallic current collectors (such as carbon cloth) have also been used in laboratory-level research [Nature Chemical Engineering, 2024, 1, 542-551; Adv. Funct. Mater. 2016, 26, 6351-6358; ACS Omega 2018, 3, 12489-12494; Adv. Mater. 2020, 32, 2001212]. Although the types of current collectors vary, their main challenges can be summarized as follows:

[0003] Poor interface and mechanical integrity: Traditional planar current collectors generally lack sufficient stability and adhesion to active electrode materials. The traditional electrode preparation method (coating a binder-containing active material slurry onto the current collector) leads to poor interface contact and agglomeration of active materials [Mater.Chem.Front., 2023, 7, 4993-5004]. During the cycle, due to changes in lattice spacing and crystal structure, the volume of the active material expands significantly, generating mechanical stress, which leads to weakened adhesion and material shedding, and the planar current collector cannot withstand these stresses [Small 2021, 17, 2102233; Small Methods 2018, 2, 1800056]. This problem leads to increased interfacial impedance, limiting rate performance and cycle life. In addition, the smooth surface of the planar current collector cannot provide sufficient electron transfer area, exacerbating polarization, dendrite formation and low charge transfer efficiency, especially at practical high current densities (4mAcm-2 ) [Joule 2018, 2(1), 110-124]. Dendrites or detached materials may even pierce the diaphragm, causing short circuits and safety risks. In addition, although polymer binders can provide some adhesion, they hinder electron movement, increase internal impedance, and increase flammability risks due to their low ignition point [Nature Energy 2020, 5, 786-793].

[0004] Low mass loading of active materials: Active materials grown directly on current collectors usually have difficulty meeting the mass loading requirements (>10 mg cm -2 ), while laboratory evaluation is usually based on low mass loading electrodes (<2 mg cm -2 )[Small2024,20,2308126;Energy Environ.Sci.,2021,14,576-601]. When expanded to commercial mass loading, the thicker electrodes significantly extend the ion transport and electron transfer paths, resulting in sluggish charge dynamics. High mass loading requires more charge to be stored and transferred per unit area and time, which will reduce rate performance and cycle stability due to tight structure limiting active site exposure, inhibiting redox reaction kinetics and increasing impedance [Electrochemical Energy Reviews,2021,4:382-446;Adv.Funct.Mater.,2019,29(34),1903961;Adv.Energy Mater.,2019,9(33),1901457].

[0005] Heavy weight and poor flexibility: The weight, thickness and poor interfacial contact of the current collector also hinder the preparation of flexible electrodes, while requiring them to maintain stable electrochemical performance under deformation conditions [Adv. Funct. Mater. 2023, 33, 2305515]. In addition, metal current collectors are easily corroded and occupy about 15% (Al) and 50% (Cu) of the total weight and volume of the positive and negative electrodes, significantly reducing the overall energy density [Chemical Engineering Journal 446 (2022) 136860]. Although carbon cloth is lightweight, flexible and conductive, its inherent hydrophobicity, poor affinity for electroactive materials and low capacity contribution limit its applicability in industrial applications [Energy Storage Materials 48 (2022) 172–190]. Summary of the invention

[0006] In view of this, the present invention, in a first aspect, provides a molybdenum-based current collector composite material, the molybdenum-based current collector composite material comprising a substrate and a molybdenum-based nanomaterial coated on the surface thereof; the substrate is a carbon cloth;

[0007] The molybdenum-based nanomaterial includes MoO 2 -Mo 2 N and Mo 2 At least one of N nanostructures.

[0008] Preferably, the molybdenum-based current collector composite material has a three-dimensional nanoarray structure consisting of interconnected, vertically arranged clustered nanowires, and the nanowires are uniformly anchored on the entire surface of the carbon cloth fiber.

[0009] More preferably, the average diameter of the nanowires is 20-100 nm.

[0010] In a second aspect, a method for preparing the molybdenum-based current collector composite material of the present invention is provided, comprising the following steps:

[0011] S1: pretreated commercial carbon cloth;

[0012] S2: Mo functionalization is achieved on the pretreated carbon cloth through a seed-assisted hydrothermal process to grow MoO 3 Nanowires;

[0013] S3: In NH 3 The annealing treatment is carried out under an atmosphere to obtain a molybdenum-based current collector composite material.

[0014] Preferably, the pretreatment process includes first treating with concentrated nitric acid, and then washing with distilled water and ethanol in an ultrasonic bath respectively.

[0015] Preferably, the seed-assisted hydrothermal process comprises the following steps: first, preparing a seed growth solution: adding sodium molybdate dihydrate to a mixture of distilled water and concentrated hydrochloric acid, soaking the pretreated carbon cloth therein, and then drying it on a hot plate; repeating the process three times, and finally forming a blue MoO on the carbon cloth. 3 Nanoparticle film; the second step is hydrothermal reaction: distilled water, nitric acid and ammonium heptamolybdate are mixed to prepare a clear and uniform solution, the solution is magnetically stirred at room temperature for 15 minutes, and then transferred to a high-pressure reactor to 3 The nanoparticle membrane is placed therein, heated, cooled naturally to room temperature, taken out and washed with distilled water, and dried overnight to obtain the membrane.

[0016] Preferably, the annealing temperature is 500-700° C., the annealing time is 3 h, the heating rate is 5° C. / min, and the ammonia flow rate is 200 sccm.

[0017] More preferably, the annealing temperature is 600° C., the annealing time is 3 h, the heating rate is 5° C. / min, and the ammonia flow rate is 200 sccm.

[0018] In a third aspect, an integrated electrode is provided, comprising the molybdenum-based current collector composite material of the present invention and an active material coated on the surface thereof;

[0019] The active material includes MoS 2 、VN、Ni 2 At least one of P, LDH, and CoP.

[0020] In a fourth aspect, a method for preparing an integrated electrode is provided, wherein the active material is assembled onto the molybdenum-based current collector composite material by hydrothermal method or electrodeposition to obtain an integrated electrode with a layered heterogeneous nanoarray structure.

[0021] In a fifth aspect, a use of the integrated electrode of the present invention in an electrochemical energy device is provided.

[0022] In some specific embodiments, the integrated electrode of the present invention is applied to lithium ion batteries (LIBs), sodium ion batteries (NIBs), potassium ion batteries (KIBs), zinc ion batteries (ZIBs) and supercapacitors. In addition, the integrated electrode of the present invention can be applied to electrocatalysis, such as as a catalyst support for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER).

[0023] In some specific embodiments, MoS is deposited on the molybdenum-based current collector composite material. 2 The obtained monolithic electrodes can provide high areal capacity and cycling stability at high current density in sodium-ion batteries (NIBs), lithium-ion batteries (LIBs), and potassium-ion batteries (KIBs).

[0024] In some specific embodiments, the monolithic electrode obtained by depositing VN on the molybdenum-based current collector composite can provide high areal capacity and cycling stability at high current density in zinc ion batteries (ZIBs).

[0025] In some specific embodiments, Ni is deposited on the molybdenum-based current collector composite material. 2 The obtained monolithic electrode can provide high surface capacitance and cycling stability at high current density in supercapacitors.

[0026] In some specific embodiments, the monolithic electrode obtained by depositing CoP on the molybdenum-based current collector composite material can provide low overpotential and high current density in the hydrogen evolution reaction (HER).

[0027] In some specific embodiments, the monolithic electrode obtained by depositing LDH on the molybdenum-based current collector composite provides low overpotential and high current density in the oxygen evolution reaction (OER).

[0028] Mechanism description

[0029] The present invention regulates the base of commercial carbon cloth and introduces functional three-dimensional transition metal nanostructures (especially molybdenum oxide / nitride, MoO 2 -Mo 2 N), prepare molybdenum-functionalized carbon cloth. Molybdenum-functionalized carbon cloth is not only an efficient electrical conductor, but also a compatible active material growth support. It has the characteristics of light weight, high thermal stability, high mechanical strength and strong electrochemical stability. Furthermore, a variety of active materials are grown directly on molybdenum-functionalized carbon cloth to form an integrated electrode, which is designed for metal ion batteries (such as sodium ion, lithium ion, potassium ion, zinc ion batteries), supercapacitors and water decomposition applications. These integrated electrodes effectively alleviate the stress problem caused by volume expansion through the three-dimensional nanoarray architecture of molybdenum-functionalized current collectors. As an independent discrete unit, the three-dimensional structure enhances the structural stability of the active layer, regulates the electric field distribution, reduces the local current density, and promotes uniform nucleation during the cycle. In addition, the incompletely coordinated molybdenum metal center provides active sites for chemical bonding with the active material, strengthens the interface contact, improves the mechanical integrity, and reduces the impedance and battery polarization. At the same time, the three-dimensional vertically arranged morphology increases the surface area, supports high mass loading, and optimizes the charge transfer efficiency, thereby improving the area capacity, rate performance, cycle stability and reaction kinetics.

[0030] The above scheme of the present invention has the following beneficial effects:

[0031] (1) The present invention functionalizes commercial carbon cloth into molybdenum-functionalized carbon cloth by substrate regulation, specifically using MoO 2 -Mo 2 The N nanoarray structure is used to enhance the interface between the current collector and the active material. Unlike the traditional slurry-coated electrodes on metal or carbon cloth current collectors, which rely on binders and additives and result in significant resistance, the present invention loads the active material onto the molybdenum functionalized carbon cloth in a high mass manner through a binder-free direct anchoring method, thereby significantly reducing the interface resistance and forming an integrated electrode.

[0032] (2) The molybdenum-functionalized carbon cloth of the present invention has good structural stability, thermal stability, improved electrical conductivity, mechanical strength and electrochemical stability. In addition, its three-dimensional hierarchical structural integrity, characterized by well-arranged nanoarray repeating structural units, makes it a preferred substrate for designing integrated electrodes, enabling high mass loading of active materials while effectively reducing interfacial impedance in the electrode. The strong covalent bonding of the active materials along the vertical nanowires gives the entire electrode superior macroscopic mechanical and electrical properties, facilitating rapid charge transport and enhanced reaction kinetics. During processing, the loading amount can be adjusted according to the optimization requirements.

[0033] (3) The molybdenum-functionalized carbon cloth of the present invention has scalable manufacturing and compatibility. The material used to modify the carbon cloth (MoO 2 -Mo 2 N) is non-toxic and easy to deposit, enabling direct growth of active materials. The crystal structure of the exposed surface is highly matched to that of the active material, ensuring a strong interface contact between the current collector and the active material, facilitating the fabrication of binder-free integrated electrodes. In addition, hydrothermal and electrodeposition methods allow for scalable and facile growth of a variety of active materials, such as MoS 2 , VN and Ni 2 P, as well as electrodeposition of LDH and CoP.

[0034] (4) The molybdenum-functionalized carbon cloth of the present invention has high performance and durability. The molybdenum-functionalized carbon cloth enhances the electrochemical performance of metal ion batteries by providing additional capacity and maintaining long-term cycle stability while maintaining structural integrity, thanks to its covalent interface that enhances the battery life. The strong three-dimensional nanoarray structure provides sufficient buffer space for the internal stress caused by the significant volume change of the active material during repeated charge and discharge. This design effectively slows down the electrode pulverization and reduces the risk of failure in long-term cycles.

[0035] (5) The molybdenum-functionalized carbon cloth of the present invention is safe and versatile. The polymer binder and conductive additive are removed, and the use of toxic chemicals and materials is avoided, thereby reducing the risk of explosion or fire caused by local overheating in batteries and supercapacitors. In addition, the molybdenum-functionalized carbon cloth and its integrated electrode have the advantages of light weight and flexibility, so that it can be customized into the required shape and size according to different electrochemical application requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 Surface morphologies of Mo-functionalized carbon cloth obtained at different nitriding temperatures in the embodiments of the present invention and the pure carbon cloth in Comparative Example 1; wherein (a) is Comparative Example 1, (b) is Embodiment 1, (c) is Embodiment 2, and (d) is Embodiment 3;

[0038] Figure 2 1 is the XRD spectra of the Mo-functionalized carbon cloth obtained at different nitriding temperatures in the embodiment of the present invention and the pure carbon cloth in Comparative Example 1;

[0039] Figure 3 is a digital image of the thickness of the Mo-functionalized carbon cloth obtained at different nitriding temperatures in the embodiment of the present invention and the pure carbon cloth of Comparative Example 1;

[0040] Figure 4 : Sheet resistance, tensile stress-strain curve, thermal map and BET surface area relationship diagram of the Mo-functionalized carbon cloth obtained at different nitriding temperatures in the embodiment of the present invention and the pure carbon cloth of Comparative Example 1;

[0041] Figure 5 The MoS of Example 4 of the present invention 2 Integrated electrode and CC-MoS of Comparative Example 4 2 Surface morphology of the electrode;

[0042] Figure 6 The Mo-600 of Example 2 and the MoS of Example 4 are 2 Integrated electrode and CC-MoS of Comparative Example 4 2 XRD spectrum of the electrode;

[0043] Figure 7 The MoS of Example 4 of the present invention 2 Integrated electrode and CC-MoS of Comparative Example 4 2 Digital image display of electrodes;

[0044] Figure 8 The MoS of Example 4 of the present invention 2 Integrated electrode and CC-MoS of Comparative Example 4 2 Sheet resistance, tensile stress-strain curve, thermal map and BET surface area relationship diagram of the electrode;

[0045] Fig. 9The electrochemical performance of sodium ion storage of the Mo-functionalized carbon cloth obtained at different nitriding temperatures in the embodiment of the present invention and the pure carbon cloth of Comparative Example 1; wherein (a) CV, (b) EIS, (c) rate performance and (d) cycle stability;

[0046] Fig.10 The Mo-600 of Example 2 and the MoS of Example 4 are 2 Integrated electrode and CC-MoS of Comparative Example 4 2 Electrochemical performance of the electrode for sodium ion storage; including (a) CV, (b) EIS, (c) rate performance and (d) cycle stability;

[0047] Fig.11 The Mo-600 of Example 2 and the MoS of Example 4 are 2 Integrated electrode and CC-MoS of Comparative Example 4 2 Electrochemical performance of potassium ion storage of the electrode; (a) rate performance, (b) cycle stability; and electrochemical performance of zinc ion storage of Mo-600 of Example 2, VN integrated electrode of Example 5 and CC-VN electrode of Comparative Example 5; (c) rate performance, (d) cycle stability;

[0048] Fig.12 The electrochemical properties of the supercapacitor of the Ni2P integrated electrode of Example 6 of the present invention and the CC-Ni2P electrode of Comparative Example 6; (ab) GCD curves, (c) rate performance; and the electrochemical performance of water decomposition of the pure carbon cloth of Comparative Example 1, CC-CoP or CC-LDH of Comparative Example 7, Mo-600 of Example 2, and the CoP-based monolithic electrode or LDH-based monolithic electrode of Example 7; (d) HER performance, (e) OER performance. DETAILED DESCRIPTION

[0049] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0050] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0051] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0052] In view of the existing problems, a molybdenum-based current collector composite material, an integrated electrode, and a preparation method and application thereof are provided.

[0053] Example 1

[0054] This embodiment provides a method for preparing a molybdenum-based current collector composite material.

[0055] The method of this embodiment specifically includes the following steps:

[0056] Step 1: Pre-treat the carbon cloth: Take a 6.0cm 2 The carbon cloth samples (purchased from Fuel Cell Earth LLC, Woburn, Massachusetts, USA) were first treated with concentrated nitric acid (HNO 3 ) and then cleaned with distilled water and ethanol in an ultrasonic bath (Master-S15Q, HHitech Instruments Co. Ltd., Shanghai, China) for 10 min, respectively.

[0057] Step 2: Seed-assisted hydrothermal process: First, prepare the seed growth solution by mixing 2.5 g of sodium molybdate dihydrate (Na 2 MoO 4 ·2H 2 O) was added to a mixture of 20 mL of distilled water and 5 mL of concentrated hydrochloric acid (37 wt%), and the pretreated carbon cloth was immersed in the solution for 2 minutes and then dried on a hot plate at 390 ° C for 1 minute; this process was repeated three times, and finally a blue MoO was formed on the carbon cloth. 3 The nanoparticle film (labeled as CC-MoO 3 Then, a hydrothermal reaction was carried out: 17.0 mL of distilled water and 3.0 mL of nitric acid (HNO 3 ) and 0.5 g ammonium heptamolybdate [(NH 4 ) 6 Mo 7 O 24 ] to prepare a clear and homogeneous solution, which was magnetically stirred at room temperature for 15 minutes and then transferred to a Teflon-lined stainless steel autoclave (25 mL) to 3 Place it in the oven and heat it at 180°C for 10 minutes at a heating rate of 10°C / min. After cooling naturally to room temperature, take out the CC-MoO 3 , and washed with distilled water, and finally dried in an electric oven at 60 °C overnight.

[0058] Step 3: Preparation of molybdenum functionalized carbon cloth: 3 In ammonia (NH 3 ) atmosphere at 500 ° C for 3 hours, the heating rate was 5 ° C / min, and the ammonia flow rate was 200 sccm, thereby obtaining a molybdenum-functionalized carbon cloth sample, denoted as Mo-500, and the thickness of the molybdenum-functionalized carbon cloth was 0.36 mm (see Figure 3 ).

[0059] Comparative Example 1

[0060] The original commercial carbon cloth, without any treatment, has a thickness of 0.22 mm (see Figure 3 ).

[0061] Example 2

[0062] The difference between this embodiment and embodiment 1 is that the annealing temperature is 600°C, and the other steps and parameters are the same as those in embodiment 1. The prepared molybdenum functionalized carbon cloth is denoted as Mo-600 and has a thickness of 0.38 mm (see Figure 3 ).

[0063] Comparative Example 2

[0064] The difference between this comparative example and Example 1 is that the prepared 2 C / MoN functionalized carbon cloth, the specific preparation process can be found in the literature [Nano Energy 2024, 125, 109590; Small 2024, 2311773].

[0065] Example 3

[0066] The difference between this embodiment and embodiment 1 is that the annealing temperature is 700° C., and the other steps and parameters are the same as those in embodiment 1. The prepared molybdenum functionalized carbon cloth is denoted as Mo-700 and has a thickness of 0.38 mm (see Figure 3 ).

[0067] Comparative Example 3

[0068] The difference between this comparative example and Example 1 is that the prepared 2 / TiN functionalized carbon cloth functionalized carbon cloth, the specific preparation process can be referred to references [Small 2024,20,2307103; Small 2024,2312036].

[0069] The molybdenum-functionalized carbon cloth obtained by different nitridation temperatures in the above examples has a typical three-dimensional nanoarray structure, consisting of interconnected, vertically arranged clustered nanowires with an average diameter of about 20-100 nm, uniformly anchored on the entire surface of the carbon cloth fiber, as shown in the scanning electron microscope (SEM) image ( Figure 1 b-1d). This is different from the smooth surface of the original carbon cloth of Comparative Example 1 ( Figure 1 a) Create contrast.

[0070] X-ray diffraction (XRD) analysis showed that the Mo-functionalized carbon cloth obtained at 500℃ and 600℃ had a strong affinity with MoO 2(JCPDSNo.32–0671) and Mo 2 The XRD peaks of the N (JCPDS No. 25–1366) phase are completely aligned. However, the XRD peaks of the sample obtained at 700°C only correspond to the Mo 2 N phase, while the original carbon cloth shows peaks corresponding to carbon (JCPDS No.26-1077) at 25.4° and 43.4° ( Figure 2 ).

[0071] The sheet resistance of the molybdenum-functionalized carbon cloth obtained at different nitriding temperatures is 126.2Ω / sq, 100.9Ω / sq, and 128.4Ω / sq, respectively, which is lower than that of the original carbon cloth (156.6Ω / sq), and the conductivity (0.22S cm -1 , 0.20S cm -1 and 0.20S cm -1 ) is close to the original carbon cloth (0.29S cm -1 )( Figure 4 a).

[0072] The tensile strength of the molybdenum-functionalized carbon cloth obtained at 600 °C is 13.2 MPa, which is six times that of the original carbon cloth (2.83 MPa), and the fracture strain is 6%, which is higher than 4% of the original carbon cloth, as shown in the tensile stress-strain curve ( Figure 4 b). Molybdenum functionalization enhances the thermal stability of carbon cloth, which can remain stable at 1000°C ( Figure 4 c). Among them, the BET surface area of ​​the molybdenum-functionalized carbon cloth obtained at 600 °C is 15.19 m 2 g -1 ( Figure 4 d), while the original carbon cloth has no measurable surface area.

[0073] Example 4

[0074] This embodiment provides a method for preparing an integrated electrode.

[0075] The method of this embodiment specifically includes the following steps:

[0076] MoS 2 As active material: using hydrothermal reaction method, add thiourea (H 2 NCSNH 2 , 0.01mmol) and sodium molybdate dihydrate (Na 2 MoO 4 ·2H 2O, 0.0025mmol) solution, and magnetic stirring. The mixed solution and the molybdenum functionalized carbon cloth prepared in Example 2 were transferred to a 25mL Teflon-lined stainless steel autoclave, and then heated at 180°C for 8 hours. After the reaction, the product was washed with distilled water and ethanol, and dried in an electric oven at 60°C overnight, and finally MoS was formed on the molybdenum functionalized carbon cloth. 2 Nanosheets, MoS 2 Integrated electrode.

[0077] Comparative Example 4

[0078] The difference between this comparative example and Example 4 is that the original carbon cloth is used to directly deposit the active material to prepare the electrode, and the CC-MoS 2 .

[0079] The integrated electrode derived from the molybdenum functionalized carbon cloth prepared above has the following characteristics:

[0080] MoO obtained at 600℃ 2 -Mo 2 N acts as an ideal current collector / substrate, providing abundant nucleation sites and promoting the formation of MoS 2 Assembly of active materials to form MoS 2 Integrated electrode.

[0081] MoS 2 The nanosheets are uniformly wrapped and clearly visible along the MoO 2 -Mo 2 N nanowire planes form heterojunction interfaces ( Figure 5 a). MoS grown on pristine carbon cloth 2 Nanosheets (labeled as CC-MoS 2 ) are densely packed ( Figure 5 b).

[0082] MoS 2 Phase in integrated electrode and CC-MoS 2 The XRD patterns of Figure 6 ).MoS 2 The integrated electrode has a high mass loading of 11.88 mg cm -2 , thickness is 0.42mm( Figure 7 a). The same mass loading was applied to the pristine carbon cloth (CC-MoS 2 ), the thickness is 0.35mm( Figure 7 b) The MoS 2 The sheet resistance of the integrated electrode is 116.9Ω / sq and the conductivity is 0.203S cm -1 , better than CC-MoS 2(137Ω / sq)( Figure 8 a). In addition, MoS 2 The tensile strength of the integrated electrode is 19.4 MPa, which is higher than that of CC-MoS 2 (17.7MPa), the fracture strain is 5.7%, exceeding that of CC-MoS 2 4%, the tensile stress-strain curve is as follows Figure 8 b. MoS 2 The integrated electrode also shows better performance than CC-MoS 2 The electrode has higher thermal stability and can withstand temperatures up to 1000°C ( Figure 8 c) MoS 2 The BET surface area of ​​the integrated electrode is 11.58 m 2 g -1 , while CC-MoS 2 There is no measurable surface area ( Figure 8 d).

[0083] Example 5

[0084] This embodiment provides a method for preparing an integrated electrode.

[0085] The method of this embodiment specifically includes the following steps:

[0086] VN as active material: VN nanosheets were grown on Mo-functionalized carbon cloth using a hydrothermal reaction method. In a typical synthesis process, 0.117 g of NH 4 VO 3 Dissolve in 2 mL of aqueous ammonia (NH 3 ·H 2 0) and 30 mL of distilled water until a transparent solution is formed. Then, 0.525 g of C 2 H 5 NS, and magnetic stirring was performed. The mixed solution was transferred to a 25 mL Teflon-lined stainless steel autoclave together with the molybdenum-functionalized carbon cloth prepared in Example 2, and heated at 180°C for 6 hours. After the reaction, the product was washed with distilled water and ethanol and dried in an electric oven at 60°C overnight. Finally, the product was heated at 700°C in ammonia (NH 3 ) atmosphere for 150 minutes with a heating rate of 5°C / min and a gas flow rate of 100 sccm, and finally VN nanosheets are formed on the molybdenum-functionalized carbon cloth to obtain a VN integrated electrode.

[0087] Comparative Example 5

[0088] The difference between this comparative example and Example 5 is that VN nanosheets are grown on the original carbon cloth to prepare the electrode, which is called CC-VN.

[0089] Example 6

[0090] This embodiment provides a method for preparing an integrated electrode.

[0091] The method of this embodiment specifically includes the following steps:

[0092] Ni 2 P as active material: Preparation of Ni by hydrothermal reaction and phosphating 2 The typical synthesis process is to mix 10 mmol hexamethyltetramine (HMTA) and 5 mmol nickel nitrate (Ni(NO 3 ) 2 ) was dissolved in 35 ml of distilled water and stirred evenly using a magnetic stirrer. The solution and the molybdenum-functionalized carbon cloth prepared in Example 2 were transferred to a 50 ml Teflon-lined stainless steel autoclave and heated at 120°C for 12 hours. The Ni(OH) 2 The material was washed with distilled water and ethanol and then dried in an electric oven at 60°C overnight. 2 Annealing was performed using sodium hydrogen phosphate (NaH 2 PO 2 ) powder was placed upstream of the gas flow as a phosphorus source and annealed at 350°C for 120 minutes in an argon (Ar) atmosphere with a heating rate of 5°C / min and a gas flow rate of 200 sccm. The annealed product was washed with distilled water and ethanol and finally dried in an electric oven at 60°C to obtain Ni 2 P monomer electrode.

[0093] Comparative Example 6

[0094] The difference between this comparative example and Example 6 is that Ni 2 P nanosheets to prepare the electrode, called CC-Ni 2 P.

[0095] Example 7

[0096] This embodiment provides a method for preparing an integrated electrode.

[0097] The method of this embodiment specifically includes the following steps:

[0098] CoP or LDH as active material: CoP or LDH material is deposited on the molybdenum-functionalized carbon cloth prepared in Example 2 by electrochemical deposition.

[0099] Preparation of LDH precursor solution: nickel nitrate (Ni(NO 3 ) 2 6H 2 O) and ferric nitrate (Fe(NO3 ) 3 9H 2 O) was dissolved in deionized water.

[0100] Preparation of CoP precursor solution: Cobalt nitrate (Co(NO 3 ) 2 6H 2 O) and sodium phosphite (NaH 2 PO 2 ·H 2 O) was prepared by dissolving in deionized water at a molar ratio of 1:1.

[0101] The electrodeposition process adopts a three-electrode system, in which Mo-functionalized carbon cloth (0.25 cm 2 ) as the working electrode, the carbon rod as the counter electrode, and the saturated Ag / AgCl electrode as the reference electrode. A constant potential of -1.2 V (relative to Ag / AgCl) was applied for 30 seconds, which could be adjusted as needed to obtain the desired active layer thickness. After the deposition was completed, the obtained electrode was thoroughly rinsed with deionized water and dried at room temperature.

[0102] Comparative Example 7

[0103] The difference between this comparative example and Example 7 is that CoP or LDH is grown on the original carbon cloth to prepare the electrode, which is called CC-CoP or CC-LDH.

[0104] application

[0105] The electrochemical performance of the above-mentioned single-piece electrode was tested in a CR2032 button cell. The battery assembly specifically includes the following process:

[0106] NIB half-cell: The cells were assembled in an argon-filled glove box (Mikrouna Co. Ltd., China) using the prepared electrodes (1 cm 2 ) as the working electrode, Na foil as the counter electrode and reference electrode, 1M NaClO 4 Dissolved in ethylene carbonate (EC) / dimethyl carbonate (DMC) (1:1 v / v) + 5.0% fluoroethylene carbonate (FEC) was used as the electrolyte, and Whatman GF / D was used as the separator.

[0107] LIB half-cell: Use the prepared electrode as the working electrode, Li foil as the counter electrode and reference electrode, 1M LiPF 6 Dissolved in EC:DMC (1:1 v / v) as the electrolyte and PE as the separator.

[0108] KIB half-cell: The prepared electrode was used as the working electrode, K foil was used as the counter electrode and reference electrode, 1M KFSI dissolved in EC:DMC (1:1 v / v) was used as the electrolyte, and Whatman GF / D was used as the separator.

[0109] ZIB: The prepared electrode was used as the working electrode to assemble a button cell at room temperature. 4 as electrolyte, Zn sheet as negative electrode, and Whatman GF / A as separator.

[0110] Supercapacitor assembly: The supercapacitor performance of the single electrode was tested in a three-electrode assembly using the prepared electrodes (1 cm 2 ) as the working electrode, carbon rod as the counter electrode, saturated Ag / AgCl as the reference electrode, and 1M KOH solution as the electrolyte. At different current densities, constant current charge-discharge curves were obtained in the potential range of 0 to 0.4 V, and the area capacitance was calculated from the curves.

[0111] Electrolysis test: HER (hydrogen evolution reaction) and OER (oxygen evolution reaction) performance was tested in a three-electrode assembly using Mo-functionalized carbon cloth (0.25 cm 2 ) as the working electrode, carbon rod as the counter electrode, saturated Ag / AgCl as the reference electrode, and 1M KOH solution as the electrolyte. Linear sweep voltammetry (LSV) was used for the test with a scan rate of 1mV / s. All potentials were calibrated to the reversible hydrogen electrode.

[0112] In the present invention, molybdenum-functionalized carbon cloth samples obtained at different nitridation temperatures were used as current collectors to test their electrochemical performance in sodium ion batteries (NIBs):

[0113] Cyclic voltammetry (CV) showed that all Mo-functionalized carbon cloth samples were electrochemically active, among which the sample obtained at 600 °C showed the largest CV area, indicating that it was electrochemically active in Na + The best electrochemical activity in storage ( Fig. 9 a).

[0114] Electrochemical impedance spectroscopy (EIS) showed that the charge transfer impedance of the Mo-functionalized carbon cloth was low, ranging from 36.5Ω to 39.1Ω ( Fig. 9 b).

[0115] The Mo-functionalized carbon cloth sample obtained at 600℃ showed a high charge / discharge rate at 1 mA cm -2 The capacity contribution at this current density is 2.702 mAh cm -2In comparison, the 500℃ and 700℃ samples have 2.016 and 1.626 mAh cm -2 ( Fig. 9 c). The sample still maintains excellent cycling stability after 500 cycles. -2 Keep 1mAhcm -2 Capacity( Fig. 9 d).

[0116] Based on the excellent performance of Mo-functionalized carbon cloth obtained at 600 °C, MoS 2 Performance of integrated electrodes in sodium-ion batteries:

[0117] MoS 2 The CV curves of the integrated electrode show a significantly larger area and a different shape, indicating that it is different from CC-MoS 2 Compared with Fig.10 a).

[0118] EIS shows that MoS 2 The charge transfer impedance of the integrated electrode is 21.58Ω, which is better than CC-MoS 2 200Ω( Fig.10 b).

[0119] MoS 2 The integrated electrode is at 1 mA cm -2 The high areal capacity is 7.35 mAh cm at a current density of 1. -2 , at 24mAcm -2 Even at a high current density of 1.4 mAh cm -2 ( Fig.10 c). It also exhibits excellent cycling stability at 5 mA cm -2 At the same current density, it still maintains 1.2 mAh cm after 400 cycles. -2 The area capacity of CC-MoS 2 It experienced severe capacity decay and poor cycling stability.

[0120] For potassium ion storage, MoS 2 The integrated electrode is at 1 mA cm -2 3.16 mAh cm -2 The area capacity ( Fig.11 a) and at 5 mA cm -2 Excellent cycle stability, with good capacity retention after 500 cycles ( Fig.11 b) CC-MoS 2 It shows severe capacity decay.

[0121] For Zn-ion storage, vanadium nitride (VN) was grown on molybdenum-functionalized carbon cloth. The VN integrated electrode was tested at 1 mA cm -2 3.33 mAh cm -2 The area capacity at 12 mA cm -2 The lower one is 0.59 mAh cm -2 ( Fig.11 c) and at 4 mA cm -2 Excellent 500-cycle stability ( Fig.11 d).

[0122] In supercapacitor applications, Ni 2 P grown on Mo-functionalized carbon cloth provided 4.84 F cm -2 High area capacitance at 6 mA cm -2 The performance is better under Fig.12 a-12c).

[0123] In the present invention, molybdenum-functionalized carbon cloth obtained at 600 °C was used as a substrate for electrodeposition of active materials, such as CoP and LDH, and the derived electrodes were used for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1 M KOH: in HER, the CoP integrated electrode significantly reduced the overpotential to 259 mV, which was better than that of CC-LDH electrode (448 mV), indicating its excellent catalytic activity ( Fig.12 d). In OER, the overpotential of the LDH integrated electrode is 313 mV, which is lower than that of the CC-LDH electrode (382 mV). Fig.12 e).

[0124] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A molybdenum-based current collector composite material, characterized in that: The molybdenum-based current collector composite material comprises a substrate and a molybdenum-based nanomaterial coated on the surface of the substrate; the substrate is a carbon cloth; The molybdenum-based nanomaterial includes at least one of MoO2-Mo2N and Mo2N nanostructures.

2. The molybdenum-based current collector composite material according to claim 1, characterized in that: The molybdenum-based current collector composite material has a three-dimensional nano-array structure consisting of interconnected, vertically arranged clustered nanowires, and the nanowires are uniformly anchored on the entire surface of the carbon cloth fiber.

3. The molybdenum-based current collector composite material according to claim 1, characterized in that: The average diameter of the nanowires is 20-100 nm.

4. The method for preparing the molybdenum-based current collector composite material according to claim 1, characterized in that: The steps include: S1: pretreated commercial carbon cloth; S2: Mo functionalization is achieved on the pretreated carbon cloth through a seed-assisted hydrothermal process to grow MoO3 nanowires; S3: performing annealing treatment in an NH3 atmosphere to obtain a molybdenum-based current collector composite material.

5. The preparation method according to claim 4, characterized in that: The pretreatment process includes first treating with concentrated nitric acid, and then washing with distilled water and ethanol in an ultrasonic bath respectively.

6. The preparation method according to claim 4, characterized in that: The seed-assisted hydrothermal process includes: a first step of preparing a seed growth solution: adding sodium molybdate dihydrate to a mixture of distilled water and concentrated hydrochloric acid, immersing the pretreated carbon cloth in the solution, and then drying on a heating plate; repeating the process three times to eventually form a blue MoO3 nanoparticle film on the carbon cloth; a second step of performing a hydrothermal reaction: mixing distilled water, nitric acid and ammonium heptamolybdate to prepare a clear and uniform solution, stirring the solution magnetically at room temperature for 15 minutes, and then transferring the solution to a high-pressure reactor, placing the MoO3 nanoparticle film therein, heating it, and naturally cooling it to room temperature, then taking it out and washing it with distilled water, and drying it overnight.

7. The preparation method according to claim 4, characterized in that: The annealing temperature is 500-700° C., the annealing time is 3 h, the heating rate is 5° C. / min, and the ammonia flow rate is 200 sccm.

8. An integrated electrode, characterized in that: A molybdenum-based current collector composite material as claimed in any one of claims 1 to 3 and an active material coated on the surface thereof; The active material includes at least one of MoS2, VN, Ni2P, LDH, and CoP.

9. The method for preparing an integrated electrode according to claim 7, characterized in that: The active material is assembled onto the molybdenum-based current collector composite material by a hydrothermal method or electrodeposition to obtain an integrated electrode with a hierarchical heterogeneous nanoarray structure.

10. Use of the integrated electrode as claimed in claim 8 in an electrochemical energy device.

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