Three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer, preparation method thereof and lithium-sulfur battery

Abstract

The invention discloses a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer, a preparation method thereof and a lithium-sulfur battery, and the preparation method comprises the following steps: placing acidified carbon cloth in a mixed solution of cobalt nitrate, nickel nitrate and hexamethylenetetramine for primary hydrothermal reaction to prepare NiCo2O4 (at) CC; the NiCo2O4 (at) CC is placed in a mixed solution of nickel chloride and sodium molybdate, a secondary hydrothermal reaction is carried out, and NiMoO4 (at) NiCo2O4 (at) CC is obtained; according to the preparation method, NiMoO4-coated NiCo2O4-coated CC is subjected to thermal reduction annealing in a mixed atmosphere of hydrogen and argon, the three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer is prepared, active sites of the three-dimensional heterostructure are increased, the oxidation-reduction reaction efficiency under high sulfur loading capacity is improved, the nano-particle anchored amorphous nanosheets form the multi-interface heterostructure, and the performance of the lithium-sulfur battery is improved. Good chemical adsorptivity and catalytic conversion on polysulfide in the battery are realized, and the cycle life of the battery is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium-sulfur battery materials and relates to a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer and a preparation method thereof, and a lithium-sulfur battery. Background Art

[0002] The demand for high-performance energy storage devices in modern society is growing exponentially, and the limitations of traditional energy storage technologies in terms of energy density, cost-effectiveness, and environmental friendliness are gradually becoming apparent. Lithium-sulfur batteries have extremely high theoretical specific capacity (1675mAh·g -1 ) and theoretical specific energy (2600Wh·kg -1 The natural abundance and low cost of sulfur make lithium-sulfur batteries an environmentally friendly and high-potential energy storage device. However, in practical applications, the cycle life and energy efficiency of lithium-sulfur batteries are severely restricted by the redox kinetics hysteresis caused by the insulation of sulfur in the cathode, the shuttle effect and active material loss caused by the electrochemical migration of polysulfides, the electrode structure collapse induced by the volume expansion during the sulfur phase transition, and the interfacial instability caused by dendrite growth on the lithium anode surface.

[0003] In response to the above problems, a large amount of research work has been conducted to explore ways to improve the performance of lithium-sulfur batteries from different parts of the battery structure, including the construction of sulfur positive electrode materials, membrane modification, the introduction of functional interlayers, and the protection of lithium negative electrodes. Introducing a functional interlayer between the positive electrode and the separator, and using the interlayer to adsorb and catalytically convert soluble polysulfides, and limit the shuttle effect of polysulfides, is an effective way to improve the performance of lithium-sulfur batteries. The role of the functional interlayer is to provide additional physical and chemical barriers while effectively catalyzing the conversion of polysulfides to reduce the "shuttle effect" of polysulfides and improve the cycle stability and rate performance of the battery. However, the existing functional interlayers have poor barrier and catalytic conversion effects on polysulfides, and the effect of inhibiting the shuttle effect still needs to be improved, resulting in poor battery cycle performance. Summary of the Invention

[0004] In response to the problems existing in the prior art, the present invention provides a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer, a preparation method thereof, and a lithium-sulfur battery, thereby solving the technical problems in the prior art that the interlayer electrocatalyst has difficulty in effectively adsorbing and catalytically converting polysulfides, resulting in a serious "shuttle effect", low sulfur utilization, lithium metal deactivation, and poor battery cycle performance.

[0005] The present invention is achieved through the following technical solutions:

[0006] A method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer comprises the following steps:

[0007] S1: adding cobalt nitrate, nickel nitrate and hexamethylenetetramine to a mixed solution of water and ethanol, stirring evenly to form solution A, placing the acidified carbon in the solution A for a hydrothermal reaction to prepare NiCo2O4@CC;

[0008] S2: placing the NiCo2O4@CC in a mixed solution of nickel chloride and sodium molybdate for a secondary hydrothermal reaction to obtain NiMoO4@NiCo2O4@CC;

[0009] S3: performing thermal reduction annealing on the NiMoO4@NiCo2O4@CC in a mixed atmosphere of hydrogen and argon to obtain the three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer.

[0010] Preferably, in step S1, the mass ratio of the cobalt nitrate, nickel nitrate and hexamethylenetetramine is (3-6):(1.5-3):(4-8).

[0011] Preferably, in step S1, the temperature of the first hydrothermal reaction is 90-130° C., and the time is 6-10 h.

[0012] Preferably, in step S1, the preparation of the acidified carbon cloth is specifically as follows: the carbon fiber cloth is ultrasonically cleaned in acetone and water in sequence, and then immersed in concentrated nitric acid, wherein the mass concentration of the concentrated nitric acid is 52% to 78%, and after treatment, it is cleaned and dried to obtain the acidified carbon cloth.

[0013] Preferably, in step S2, in the mixed solution of nickel chloride and sodium molybdate, the mass ratio of nickel chloride to sodium molybdate is (1-3):(1-3).

[0014] Preferably, in step S2, the temperature of the secondary hydrothermal reaction is 100-140° C., and the time is 2-4 hours.

[0015] Preferably, in step S3, in the mixed atmosphere of hydrogen and argon, the volume ratio of hydrogen to argon is (5-10):(90-95).

[0016] Preferably, in step S3, in the thermal reduction annealing, the reduction temperature is 300-500° C., and the reduction time is 0.5-2 h.

[0017] A three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer is prepared by the above method.

[0018] A lithium-sulfur battery comprising the above-mentioned three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer; the lithium-sulfur battery has a reversible specific capacity of 700 to 800 mAh·g after 500 cycles at a voltage range of 1.7 to 2.8 V and a rate of 1C. -1 .

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] The present invention discloses a method for preparing a three-dimensional multi-interface heterogeneous structure lithium-sulfur battery interlayer. First, an acidified carbon fiber cloth is used as a substrate. The carbon fiber cloth itself has good flexibility and conductivity and can accelerate electron transfer. The acidification not only increases the active sites on the surface of the carbon fiber cloth, which is beneficial to the subsequent crystal deposition process, but also enhances the bonding force between the substrate and the deposited layer, thereby improving the overall stability of the material. In addition, the Co 0.5 Ni 0.5 The MoNi4 alloy particles have excellent electrical conductivity and catalytic activity, and the CoO particles have strong adsorption capacity and maintain the three-dimensional staggered structure of NiCoO x and MoO 3-x Amorphous nanosheets have a large specific surface area. When used as the intermediate layer of lithium-sulfur batteries, the three-dimensional heterogeneous structure shows more active sites, which improves the redox reaction efficiency under high sulfur loading. At the same time, the nanoparticles obtained by thermal reduction (Co 0.5 Ni 0.5 , CoO and MoNi4) anchored amorphous nanosheets (NiCoO x and MoO x ) form a multi-interface heterogeneous structure, and the synergistic effect can improve the chemical adsorption of polysulfides, reduce the barrier of polysulfide conversion reaction, catalyze the reversible transformation of liquid polysulfides, and achieve good chemical adsorption and catalytic conversion of polysulfides inside the battery, effectively alleviating the "shuttle effect" of polysulfides inside the battery, improving the battery's charge and discharge specific capacity and coulombic efficiency, reducing the capacity attenuation rate, and improving the sulfur utilization rate and battery cycle life.

[0021] Furthermore, in step S1, the mass ratio of cobalt nitrate, nickel nitrate and hexamethylenetetramine is (3-6): (1.5-3): (4-8). First, cobalt nitrate and nickel nitrate are used as the main metal salt sources, and their appropriate ratio helps to form a uniform Co 0.5 Ni 0.5 With CoO, within this mass ratio range, the two can fully react to form stable nanoparticles and NiCoO x amorphous structure, thereby improving the reaction activity of the material; hexamethylenetetramine as a regulator, its appropriate addition can control the pH value and ionic strength of the solution, thereby affecting the morphology and structure of the material. Within this mass ratio range, hexamethylenetetramine can optimize the reaction conditions and promote the uniform growth and dispersion of the material.

[0022] Furthermore, in step S1, the temperature of a hydrothermal reaction is 90-130°C and the time is 6-10 hours. This temperature range can provide sufficient reaction energy to promote the full progress of the chemical reaction and form NiCo2O4 nanosheet-coated carbon cloth with stable structure and uniform composition. In addition, the appropriate hydrothermal reaction temperature and time can control the growth rate and morphology of the material. Under this condition, NiCo2O4 nanosheets can be uniformly deposited on the carbon fiber. And a longer reaction time is conducive to the crystallization and purification of the material, thereby enhancing the stability and electrochemical properties of the material. At the same time, during the hydrothermal reaction, chemical bonding will occur between the reactant molecules to form a stable chemical bond connection, which can enhance the binding force of the components inside the material and improve the overall stability and durability of the material.

[0023] Furthermore, in step S1, the preparation of the acidified carbon cloth is specifically as follows: the carbon fiber cloth is ultrasonically cleaned in acetone and water in sequence, and then immersed in concentrated nitric acid, wherein the mass concentration of the concentrated nitric acid is 52% to 78%. After treatment, it is cleaned and dried to obtain the acidified carbon cloth. The nitric acid immersion treatment can introduce a large number of oxygen-containing functional groups (such as carboxyl, hydroxyl, etc.) on the surface of the carbon fiber cloth, enhance the reactive sites of the carbon fiber cloth, increase the subsequent chemical reaction rate, and also help to improve the electrochemical properties of the material; in addition, the strong oxidizing property of nitric acid can remove impurities such as oil, dust, etc. on the surface of the carbon fiber cloth, thereby improving the purity and quality of the material. The acidified carbon fiber cloth provides a good substrate for the subsequent hydrothermal reaction and deposition process, enhances the bonding force between the deposited layer and the substrate, and thus prepares a composite material with stable structure and excellent performance.

[0024] Furthermore, in step S2, in the mixed solution of nickel chloride and sodium molybdate, the mass ratio of nickel chloride to sodium molybdate is (1-3): (1-3). Within this mass ratio range, the two can fully react to form a stable MoNi4 alloy structure, thereby improving the reactivity of the material. In addition, sodium molybdate, as a molybdenum source, also participates in the formation of amorphous MoO 3-x The formation of nanosheets can also accelerate the reaction process to a certain extent.

[0025] Furthermore, in step S2, the temperature of the secondary hydrothermal reaction is 100-140°C, and the time is 2-4 hours. Within this temperature range, the driving force of the hydrothermal reaction is sufficient, the activity of the ions in the solution and the chemical reaction rate are moderate, and a complete and continuous "sheet-in-sheet" structure is formed within a limited time; in addition, the appropriate hydrothermal reaction time can control the growth rate and morphology of the material. Within this time range, new nanosheets have enough time to nucleate and grow on the surface of old nanosheets, and can gradually cover and form a uniform "sheet-in-sheet" structure, while avoiding problems such as damage to the grown nanosheet structure, uneven growth size or irregular shape, so that the crystal structure will be more perfect and the performance of the material will be improved.

[0026] Furthermore, in step S3, the volume ratio of hydrogen and argon in the mixed atmosphere of hydrogen and argon is (5-10): (90-95). By adjusting the volume ratio of hydrogen and argon, the rate of the reduction reaction can be flexibly controlled. Within this ratio range, hydrogen can provide sufficient reducing power while avoiding material structure damage or morphological changes caused by excessive reaction rate. Therefore, this mixed gas ratio helps to maintain the flaky morphology of the material; hydrogen, as a reducing gas, can participate in the reduction reaction and reduce the metal ions in the precursor to metal particles. Within this volume ratio range, hydrogen can provide a sufficient reducing atmosphere to promote the precipitation and growth of nanoparticles. The appropriate volume ratio of hydrogen to argon helps to optimize the precipitation conditions of alloy particles. Hydrogen can penetrate into the interior of the material, promote the reduction of metal ions and the formation of nanoparticles, while argon plays a protective role, preventing the material from undergoing unnecessary chemical reactions at high temperatures. These optimized precipitation conditions help obtain uniformly distributed nanoparticles of the right size. Furthermore, during the reduction process, hydrogen also prevents particle agglomeration. Because hydrogen provides a reducing atmosphere and promotes particle precipitation, it reduces the interaction between particles and prevents them from agglomerating. This helps obtain alloy or oxide particles with good dispersion and uniform individual particle size. Furthermore, the nanoparticles can be effectively embedded in the nanosheets, forming a composite material with excellent properties.

[0027] Furthermore, in step S3, in the thermal reduction annealing, the reduction temperature is 300-500°C, and the reduction time is 0.5-2h. First, under this reduction condition, the material can maintain its flaky morphology, and under this condition, the metal ions can obtain sufficient energy to undergo a reduction reaction, thereby forming particles. As the temperature increases, the reduction reaction rate accelerates, and the precipitation rate of the particles also increases accordingly. However, too high a temperature will cause the particles to agglomerate or be too large in size, while an appropriate temperature can ensure uniform precipitation of the particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 A schematic diagram of a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC prepared in Example 1 of the present invention and a process for preparing the same;

[0030] Figure 2 This is a macroscopic photograph of a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC prepared in Example 1 of the present invention, where A is a top view and B is a side view under mechanical force;

[0031] Figure 3 These are SEM images of a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC prepared in Example 1 of the present invention at different magnifications, where the scale bar in A is 5 μm, the scale bar in B is 500 nm, and the scale bar in C is 200 nm;

[0032] Figure 4 TEM characterization image of a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC prepared in Example 1 of the present invention, wherein the scale bar in A is 200 nm, the scale bar in B is 100 nm, and the scale bar in C is 10 nm;

[0033] Figure 5 This is the element mapping distribution diagram of a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC prepared in Example 1 of the present invention;

[0034] Figure 6 This is the XRD pattern of a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC prepared in Example 1 of the present invention;

[0035] Figure 7 This is a charge and discharge curve diagram of a lithium-sulfur battery assembled with a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0036] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0037] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0038] Herein, all features such as values, amounts, amounts, and concentrations defined in numerical ranges or percentage ranges are for brevity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to include and specifically disclose all possible subranges and individual values ​​within the range (including integers and fractions).

[0039] In this document, unless otherwise specified, “include,” “including,” “contains,” “has” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0040] In this document, for the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.

[0041] like Figure 1 As shown, the present invention provides a method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer, comprising the following steps:

[0042] S1: Cobalt nitrate (Co(NO3)2·6H2O), nickel nitrate (Ni(NO3)2·6H2O), hexamethylenetetramine (C6H 12 N4) adding a mixed solution of water and ethanol and stirring uniformly to form a solution A, and subjecting the acid-washed carbon cloth (CC) and the above solution A to a hydrothermal reaction to prepare NiCo2O4@CC;

[0043] The mass ratio of cobalt nitrate, nickel nitrate and hexamethylenetetramine is (3-6):(1.5-3):(4-8); the hydrothermal growth temperature is 90-130° C., and the time is 6-10 hours.

[0044] S2: Nickel chloride (NiCl2·6H2O) and sodium molybdate (Na2MoO4·2H2O) were added to deionized water and fully dissolved to form a light green solution B. The solution was then subjected to a secondary hydrothermal reaction with NiCo2O4@CC in a reactor to obtain NiMoO4@NiCo2O4@CC.

[0045] The mass ratio of nickel chloride to sodium molybdate is (1-3):(1-3), the hydrothermal growth temperature is 100-140° C., and the time is 2-4 hours.

[0046] S3: NiMoO4@NiCo2O4@CC is subjected to thermal reduction annealing in a mixed gas atmosphere of hydrogen (H2) and argon (Ar) to obtain a three-dimensional multi-interface heterostructure interlayer H2-NiMoO4@NiCo2O4@CC.

[0047] The volume ratio of H2 and Ar is (5-10): (90-95), and during the thermal reduction process, the reduction temperature is 300-500°C and the reduction time is 0.5-2h.

[0048] The present invention also discloses a functional interlayer for a lithium-sulfur battery, which is prepared using the aforementioned three-dimensional multi-interface heterostructure interlayer H2-NiMoO4@NiCo2O4@CC. Specifically, the obtained three-dimensional multi-interface heterostructure interlayer is cut into appropriate sizes using a cutting machine to serve as the functional interlayer for the lithium-sulfur battery. Preferably, the interlayer is cut into 12-16 mm round wafers.

[0049] At the same time, the present invention also discloses a lithium-sulfur battery, including a positive electrode, an interlayer, a separator and a lithium sheet, and also includes a functional interlayer of a three-dimensional multi-interface heterostructure lithium-sulfur battery prepared by the present invention. The lithium-sulfur battery has a reversible specific capacity of 700 to 800 mAh·g after 500 cycles at a voltage range of 1.7 to 2.8 V and a rate of 1C. -1 .

[0050] The invention discloses a three-dimensional multi-interface heterogeneous structure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC and a preparation method thereof. Cobalt nitrate, nickel nitrate and hexamethylenetetramine are added to a mixed solution of deionized water and ethanol to form a light red solution A; then the acidified carbon fiber cloth and solution A are transferred to a reactor for hydrothermal reaction to obtain NiCo2O4@CC; nickel chloride and sodium molybdate are dissolved in deionized water to form a light green solution B; and the NiCo2O4@CC is subjected to secondary hydrothermal reaction in the reactor to obtain a NiMoO4@NiCo2O4@CC precursor; Co is subjected to a hydrothermal reaction in an H2 / Ar mixed gas atmosphere. 0.5 Ni 0.5MoO4@CC was subjected to thermal reduction annealing, and the three-dimensional nanosheets NiMoO4@NiCo2O4 on the carbon cloth surface reduced CoO and Co 0.5 Ni 0.5 As well as MoNi4 nanoparticles and NiCoO x with MoO 3-x Amorphous nanosheets are formed, resulting in an H2-NiMoO4@NiCo2O4@CC carbon cloth interlayer. Using carbon cloth as a substrate, the three-dimensionally connected nanosheets on the surface retain their original morphology after high-temperature thermal reduction. The resulting nanoparticles are embedded within the amorphous nanosheets. The carbon cloth substrate ensures excellent mechanical strength and a high specific surface area for the three-dimensional nanosheet structure.

[0051] The macroscopic photo of the three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC prepared by the present invention is shown in Figure 2 The carbon cloth in this material is conductive and has Co 0.5 Ni 0.5 , high conductivity and excellent catalytic performance of MoNi4 alloy particles and CoO, amorphous nanosheets NiCoO x with MoO 3-x The strong adsorption capacity of the sulfide-containing electrolyte effectively improves the shuttling effect of polysulfides as the intermediate layer of lithium-sulfur batteries, increases sulfur utilization, improves the battery's charge-discharge capacity, reduces capacity decay during the reaction process, and achieves excellent electrochemical performance. This preparation method requires simple equipment, is safe and harmless, and has a short preparation cycle. The prepared product has good electrical conductivity, chemical adsorption, and catalytic activity, making it suitable for large-scale production.

[0052] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0053] The following examples were prepared using conventional instruments and equipment in the art. Experimental methods in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or according to the conditions recommended by the manufacturer. The various raw materials used in the following examples, unless otherwise specified, were conventional commercially available products, with specifications conventional in the art. In the present specification and the following examples, unless otherwise specified, "%" indicates percentage by weight, "part" indicates parts by weight, and "ratio" indicates weight ratio.

[0054] Example 1

[0055] A method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer comprises the following steps:

[0056] Cobalt nitrate (0.6 g), nickel nitrate (0.3 g) and hexamethylenetetramine (0.8 g) were stirred in a mixed solution of 50 mL of deionized water and ethanol for 0.5 h to form a light red solution A. A 2×2 cm carbon cloth (CC) acidified with concentrated nitric acid was added to solution A and transferred to a 60 mL polytetrafluoroethylene-lined stainless steel autoclave. The stainless steel autoclave was heated to 100°C and maintained for 8 h to obtain NiCo2O4@CC. Nickel chloride (0.12 g) and sodium molybdate (0.12 g) were then added to 50 mL of deionized water and fully dissolved to form a light green solution. The NiCo2O4@CC and solution B were transferred to a 60 mL polytetrafluoroethylene-lined reactor for a secondary hydrothermal reaction at 120°C for 2 h to obtain NiMoO4@NiCo2O4@CC; NiMoO4@NiCo2O4@CC was thermally reduced in a H2 / Ar mixed gas (volume ratio of 10:90) atmosphere for 1 h at a reduction temperature of 350°C and a heating rate of 5°C / min. After natural cooling in the tubular furnace, a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC was obtained.

[0057] The SEM images of the three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC prepared in this embodiment are shown in FIG. Figure 3 , TEM Figure 4 .Depend on Figure 3 It can be seen that the surface of the functional interlayer prepared by the present invention is coated with nanosheets, and micro nanosheets are staggered on the nanosheets to form a "sheet in sheet". Figure 4 It can be seen that the metal ions are reduced to form 10-20 nm Co 0.5 Ni 0.5 and CoO particles are uniformly distributed in the amorphous NiCoO x On the nanosheet, MoNi4 particles of about 10nm are embedded in MoO 3-x Amorphous nanosheets.

[0058] The mapping test results of the three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC prepared in this embodiment are shown in Figure 5 ,Depend on Figure 5 It can be seen that Co, Ni, Mo and O are evenly distributed on the nanosheets, but in the case of Co 0.5 Ni 0.5 , CoO and MoNi4 nanoparticles, forming a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC.

[0059] The three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC prepared in this embodiment is characterized by XRD of the powder scraped from the surface of the carbon cloth. Figure 6 .Depend on Figure 6 It can be seen that there are multiple groups of diffraction peaks in the product, which are related to CoO (PDF#43-1004), Co 0.5 Ni 0.5 (PDF#04-004-8490) and MoNi4 (PDF#65-5480) standard cards match, NiCoO x with MoO 3-x It is an amorphous phase.

[0060] In order to further verify the performance of the three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC as the intermediate functional layer of the lithium-sulfur battery, the above materials were cut into 14mm diameter discs with a cutting machine as the intermediate functional layer of the lithium-sulfur battery, and assembled into a lithium-sulfur battery, and its charge and discharge performance was tested. The test results are shown in Figure 7 ,Depend on Figure 7 It can be seen that the lithium-sulfur battery obtained in this embodiment has a discharge capacity of 759 mAh·g after 500 cycles at a current density of 1 C. -1

[0061] Example 2

[0062] A method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC comprises the following steps:

[0063] Cobalt nitrate (0.3 g), nickel nitrate (0.15 g) and hexamethylenetetramine (0.4 g) were stirred in a mixed solution of 25 mL of deionized water and ethanol for 0.5 h to form a light red solution A. A 2×2 cm carbon cloth (CC) acidified with concentrated nitric acid was added to solution A and transferred to a 30 mL polytetrafluoroethylene-lined stainless steel autoclave. The stainless steel autoclave was heated to 100°C and maintained for 8 h to obtain NiCo2O4@CC. Nickel chloride (0.06 g) and sodium molybdate (0.06 g) were then added to 20 mL of deionized water and fully dissolved to form a light green solution. The NiCo2O4@CC and solution B were simultaneously transferred to a 30 mL polytetrafluoroethylene-lined reactor for a secondary hydrothermal reaction at 110°C for 8 h to obtain NiMoO4@NiCo2O4@CC. The NiMoO4@NiCo2O4@CC was thermally reduced in an atmosphere of H2 / Ar mixed gas (volume ratio of 10:90) for 0.5 h at a reduction temperature of 300°C and a heating rate of 5°C / min. After natural cooling in the tubular furnace, the three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC was obtained.

[0064] The above material was cut into 12 mm discs using a cutting machine as the functional interlayer of the lithium-sulfur battery. The lithium-sulfur battery was further prepared by using the lithium-sulfur battery interlayer. The lithium-sulfur battery obtained in this embodiment had a discharge capacity of 722 mAh·g after 500 cycles at a current density of 1 C. -1 .

[0065] Example 3

[0066] A method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC comprises the following steps:

[0067] Cobalt nitrate (0.9 g), nickel nitrate (0.45 g) and hexamethylenetetramine (1.2 g) were stirred in a mixed solution of 70 mL of deionized water and ethanol for 0.5 h to form a light red solution A. A 2×2 cm carbon cloth (CC) acidified with concentrated nitric acid was added to solution A and transferred to an 80 mL polytetrafluoroethylene-lined stainless steel autoclave. The stainless steel autoclave was heated to 120°C and maintained for 8 h to obtain NiCo2O4@CC. Nickel chloride (0.18 g) and sodium molybdate (0.18 g) were then added to 50 mL of deionized water and fully dissolved to form a light green solution. The NiCo2O4@CC and solution B were simultaneously transferred to a 60 mL polytetrafluoroethylene-lined reactor for a secondary hydrothermal reaction at 110°C for 3 h to obtain NiMoO4@NiCo2O4@CC. The NiMoO4@NiCo2O4@CC was thermally reduced in an atmosphere of H2 / Ar mixed gas (volume ratio of 5:95) for 1.5 h at a reduction temperature of 400°C and a heating rate of 5°C / min. After natural cooling in the tubular furnace, the three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC was obtained.

[0068] The above material was cut into 14 mm discs using a cutting machine as a functional interlayer of a lithium-sulfur battery. A lithium-sulfur battery was further prepared by using the lithium-sulfur battery interlayer. The lithium-sulfur battery obtained in this embodiment had a discharge capacity of 702 mAh·g after 500 cycles at a current density of 1 C. -1 .

[0069] Example 4

[0070] A method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC comprises the following steps:

[0071] Cobalt nitrate (1 g), nickel nitrate (0.5 g) and hexamethylenetetramine (1.4 g) were stirred in a mixed solution of 80 mL of deionized water and ethanol for 0.5 h to form a light red solution A. A 4×4 cm carbon cloth (CC) acidified with concentrated nitric acid was added to solution A and transferred to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave. The stainless steel autoclave was heated to 90°C and maintained for 10 h to obtain NiCo2O4@CC. Nickel chloride (0.25 g) and sodium molybdate (0.25 g) were then added to 50 mL of deionized water and fully dissolved to form a light green solution. The NiCo2O4@CC and solution B were simultaneously transferred to a 60 mL polytetrafluoroethylene-lined reactor for a secondary hydrothermal reaction at 130°C for 2 h to obtain NiMoO4@NiCo2O4@CC. The NiMoO4@NiCo2O4@CC was thermally reduced in an atmosphere of H2 / Ar mixed gas (volume ratio of 10:90) for 1 h at a reduction temperature of 450°C and a heating rate of 5°C / min. After natural cooling in the tubular furnace, a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC was obtained.

[0072] The above material was cut into 16 mm discs by a cutting machine as the functional interlayer of the lithium-sulfur battery. The lithium-sulfur battery was further prepared by using the lithium-sulfur battery interlayer. The lithium-sulfur battery obtained in this embodiment had a discharge capacity of 733 mAh·g after 500 cycles at a current density of 1 C. -1 .

[0073] Example 5

[0074] A method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC comprises the following steps:

[0075] Cobalt nitrate (1.2 g), nickel nitrate (0.6 g) and hexamethylenetetramine (1.6 g) were stirred in a mixed solution of 80 mL of deionized water and ethanol for 0.5 h to form a light red solution A. A 4×4 cm carbon cloth (CC) acidified with concentrated nitric acid was added to solution A and transferred to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave. The stainless steel autoclave was heated to 130°C and maintained for 6 h to obtain NiCo2O4@CC. Nickel chloride (0.36 g) and sodium molybdate (0.36 g) were then added to 90 mL of deionized water and fully dissolved to form a light green solution. Solution B, NiCo2O4@CC and solution B were transferred to a 100mL polytetrafluoroethylene-lined reactor for a secondary hydrothermal reaction at 140℃ for 2h to obtain NiMoO4@NiCo2O4@CC; NiMoO4@NiCo2O4@CC was thermally reduced in an atmosphere of H2 / Ar mixed gas (volume ratio of 10:90) for 1.5h at a reduction temperature of 400℃ and a heating rate of 5℃ / min. After natural cooling in the tubular furnace, a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC was obtained.

[0076] The above material was cut into 16 mm discs using a cutting machine as a functional interlayer of a lithium-sulfur battery. A lithium-sulfur battery was further prepared by using the lithium-sulfur battery interlayer. The lithium-sulfur battery obtained in this embodiment had a discharge capacity of 724 mAh·g after 500 cycles at a current density of 1 C. -1 .

[0077] Example 6

[0078] A method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC comprises the following steps:

[0079] Cobalt nitrate (0.8 g), nickel nitrate (0.4 g) and hexamethylenetetramine (0.9 g) were stirred in a mixed solution of 60 mL of deionized water and ethanol for 0.5 h to form a light red solution A. A 2×2 cm carbon cloth (CC) acidified with concentrated nitric acid was added to solution A and transferred to an 80 mL polytetrafluoroethylene-lined stainless steel autoclave. The stainless steel autoclave was heated to 100°C and maintained for 10 h to obtain NiCo2O4@CC. Nickel chloride (0.3 g) and sodium molybdate (0.3 g) were then added to 60 mL of deionized water and fully dissolved to form a Light green solution B, NiCo2O4@CC and solution B were transferred to an 80mL polytetrafluoroethylene-lined reactor for a secondary hydrothermal reaction at 100℃ for 4h to obtain NiMoO4@NiCo2O4@CC; NiMoO4@NiCo2O4@CC was thermally reduced in a H2 / Ar mixed gas (5:95) atmosphere for 2h, the reduction temperature was 300℃, the heating rate was 5℃ / min, and the three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC was obtained after natural cooling in the tubular furnace.

[0080] The above material was cut into 14 mm discs using a cutting machine as a functional interlayer of a lithium-sulfur battery. A lithium-sulfur battery was further prepared by using the lithium-sulfur battery interlayer. The lithium-sulfur battery obtained in this embodiment had a discharge capacity of 719 mAh·g after 500 cycles at a current density of 1 C. -1 .

[0081] Example 7

[0082] A method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC comprises the following steps:

[0083] Cobalt nitrate (0.5 g), nickel nitrate (0.25 g) and hexamethylenetetramine (0.6 g) were stirred in a mixed solution of 40 mL of deionized water and ethanol for 0.5 h to form a light red solution A. A 2×2 cm carbon cloth (CC) acidified with concentrated nitric acid was added to solution A and transferred to a 60 mL polytetrafluoroethylene-lined stainless steel autoclave. The stainless steel autoclave was heated to 120°C and maintained for 6 h to obtain NiCo2O4@CC. Nickel chloride (0.2 g) and sodium molybdate (0.2 g) were then added to 40 mL of deionized water and fully dissolved to form a light green solution. The NiCo2O4@CC was prepared by mixing the NiMoO4@NiCo2O4@CC with the color solution B. The NiCo2O4@CC and solution B were simultaneously transferred to a 60 mL polytetrafluoroethylene-lined reactor for a secondary hydrothermal reaction at 140°C for 2 h to obtain NiMoO4@NiCo2O4@CC. The NiMoO4@NiCo2O4@CC was thermally reduced in an atmosphere of H2 / Ar mixed gas (volume ratio of 5:95) for 2 h at a reduction temperature of 500°C and a heating rate of 5°C / min. After natural cooling in the tubular furnace, the three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC was obtained.

[0084] The above material was cut into 12 mm discs by a cutting machine as the functional interlayer of the lithium-sulfur battery. The lithium-sulfur battery was further prepared by using the lithium-sulfur battery interlayer. The lithium-sulfur battery obtained in this embodiment had a discharge capacity of 710 mAh·g after 500 cycles at a current density of 1 C. -1 .

[0085] Example 8

[0086] A method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC comprises the following steps:

[0087] Cobalt nitrate (1.8 g), nickel nitrate (0.9 g) and hexamethylenetetramine (2.2 g) were stirred in a mixed solution of 130 mL of deionized water and ethanol for 0.5 h to form a light red solution A. A 4×4 cm carbon cloth (CC) acidified with concentrated nitric acid was added to solution A and transferred to a 150 mL polytetrafluoroethylene-lined stainless steel autoclave. The stainless steel autoclave was heated to 100°C and maintained for 8 h to obtain NiCo2O4@CC. Nickel chloride (0.5 g) and sodium molybdate (0.5 g) were then added to 130 mL of deionized water and fully dissolved to form a light green solution. The NiCo2O4@CC and solution B were simultaneously transferred to a 150 mL polytetrafluoroethylene-lined reactor for a secondary hydrothermal reaction at 120°C for 3 h to obtain NiMoO4@NiCo2O4@CC. The NiMoO4@NiCo2O4@CC was thermally reduced in an atmosphere of H2 / Ar mixed gas (volume ratio of 10:90) for 1 h at a reduction temperature of 350°C and a heating rate of 5°C / min. After natural cooling in the tubular furnace, the three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer H2-NiMoO4@NiCo2O4@CC was obtained.

[0088] The above material was cut into 16 mm discs using a cutting machine as a functional interlayer of a lithium-sulfur battery. A lithium-sulfur battery was further prepared by using the lithium-sulfur battery interlayer. The lithium-sulfur battery obtained in this embodiment had a discharge capacity of 741 mAh·g after 500 cycles at a current density of 1 C. -1 .

[0089] Example 9

[0090] A method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer comprises the following steps:

[0091] S1: Add cobalt nitrate, nickel nitrate, and hexamethylenetetramine in a mass ratio of 3:1.5:4 to a mixed solution of water and ethanol, stir evenly to form solution A, place the acidified carbon cloth in the solution A, and perform a hydrothermal reaction at 90°C for 10 hours to obtain NiCo2O4@CC; wherein, the preparation of the acidified carbon cloth is specifically as follows: ultrasonically clean the carbon fiber cloth in acetone and water in sequence, and then soak it in concentrated nitric acid, wherein the mass concentration of the concentrated nitric acid is 52%, and then wash and dry it after treatment to obtain the acidified carbon cloth.

[0092] S2: Add nickel chloride and sodium molybdate in a mass ratio of 1:1 to deionized water and fully dissolve to form a light green solution B. Place the solution B together with NiCo2O4@CC in a reactor and perform a secondary hydrothermal reaction at 100°C for 4 hours to obtain NiMoO4@NiCo2O4@CC.

[0093] S3: NiMoO4@NiCo2O4@CC was placed in a mixed gas atmosphere of hydrogen and argon with a volume ratio of 5:95, and thermal reduction annealing was performed at 300°C for 2h to obtain a three-dimensional multi-interface heterostructure interlayer H2-NiMoO4@NiCo2O4@CC.

[0094] The three-dimensional multi-interface heterostructure interlayer prepared in this embodiment was cut into a suitable size and used as a functional interlayer of a lithium-sulfur battery. The lithium-sulfur battery was assembled into a lithium-sulfur battery. The lithium-sulfur battery had a reversible specific capacity of 710 mAh·g after 500 cycles at a voltage range of 1.7 to 2.8 V and a rate of 1C. -1 .

[0095] Example 10

[0096] A method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer comprises the following steps:

[0097] S1: Add cobalt nitrate, nickel nitrate, and hexamethylenetetramine in a mass ratio of 6:3:8 to a mixed solution of water and ethanol, stir evenly to form solution A, place the acidified carbon cloth in the solution A, and perform a hydrothermal reaction at 130°C for 6 hours to obtain NiCo2O4@CC; wherein, the preparation of the acidified carbon cloth is specifically as follows: ultrasonically clean the carbon fiber cloth in acetone and water in sequence, and then soak it in concentrated nitric acid, wherein the mass concentration of the concentrated nitric acid is 78%, and then wash and dry it to obtain the acidified carbon cloth.

[0098] S2: Add nickel chloride and sodium molybdate in a mass ratio of 3:2 to deionized water and fully dissolve to form a light green solution B. The solution B is then placed in a reactor together with NiCo2O4@CC and subjected to a secondary hydrothermal reaction at 140°C for 2 h to obtain NiMoO4@NiCo2O4@CC.

[0099] S3: NiMoO4@NiCo2O4@CC was placed in a mixed gas atmosphere of hydrogen and argon with a volume ratio of 10:90, and thermal reduction annealing was performed at 500°C for 0.5h to obtain a three-dimensional multi-interface heterostructure interlayer H2-NiMoO4@NiCo2O4@CC.

[0100] The three-dimensional multi-interface heterostructure interlayer prepared in this embodiment was cut into a suitable size and used as a functional interlayer of a lithium-sulfur battery. The lithium-sulfur battery was assembled into a lithium-sulfur battery. The lithium-sulfur battery had a reversible specific capacity of 750 mAh·g after 500 cycles at a voltage range of 1.7 to 2.8 V and a rate of 1C. -1 .

[0101] Example 11

[0102] A method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer comprises the following steps:

[0103] S1: Add cobalt nitrate, nickel nitrate, and hexamethylenetetramine in a mass ratio of 4:2:5 to a mixed solution of water and ethanol, stir evenly to form solution A, place the acidified carbon cloth in the solution A, and perform a hydrothermal reaction at 100°C for 8 hours to obtain NiCo2O4@CC; wherein, the preparation of the acidified carbon cloth is specifically as follows: ultrasonically clean the carbon fiber cloth in acetone and water in sequence, and then soak it in concentrated nitric acid, wherein the mass concentration of the concentrated nitric acid is 60%, and then wash and dry it after treatment to obtain the acidified carbon cloth.

[0104] S2: Add nickel chloride and sodium molybdate in a mass ratio of 2:3 to deionized water and fully dissolve to form a light green solution B. The solution B is placed together with NiCo2O4@CC in a reactor and subjected to a secondary hydrothermal reaction at 120°C for 3 h to obtain NiMoO4@NiCo2O4@CC.

[0105] S3: NiMoO4@NiCo2O4@CC was placed in a mixed gas atmosphere of hydrogen and argon with a volume ratio of 8:92, and thermal reduction annealing was performed at 400°C for 1h to obtain a three-dimensional multi-interface heterostructure interlayer H2-NiMoO4@NiCo2O4@CC.

[0106] The three-dimensional multi-interface heterostructure interlayer prepared in this embodiment was cut into a suitable size and used as a functional interlayer of a lithium-sulfur battery. The lithium-sulfur battery was assembled into a lithium-sulfur battery. The lithium-sulfur battery had a reversible specific capacity of 770 mAh·g after 500 cycles at a voltage range of 1.7 to 2.8 V and a rate of 1C. -1 .

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer, characterized in that: The following steps are involved: S1: adding cobalt nitrate, nickel nitrate and hexamethylenetetramine to a mixed solution of water and ethanol, stirring evenly to form solution A, placing the acidified carbon in the solution A for a hydrothermal reaction to prepare NiCo2O4@CC; S2: placing the NiCo2O4@CC in a mixed solution of nickel chloride and sodium molybdate for a secondary hydrothermal reaction to obtain NiMoO4@NiCo2O4@CC; S3: performing thermal reduction annealing on the NiMoO4@NiCo2O4@CC in a mixed atmosphere of hydrogen and argon to obtain the three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer.

2. The method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer according to claim 1, characterized in that: In step S1, the mass ratio of the cobalt nitrate, nickel nitrate and hexamethylenetetramine is (3-6):(1.5-3):(4-8).

3. The method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer according to claim 1, characterized in that: In step S1, the temperature of the first hydrothermal reaction is 90-130° C., and the time is 6-10 hours.

4. The method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer according to claim 1, characterized in that: In step S1, the preparation of the acidified carbon cloth is specifically as follows: the carbon fiber cloth is ultrasonically cleaned in acetone and water in sequence, and then immersed in concentrated nitric acid, wherein the mass concentration of the concentrated nitric acid is 52% to 78%. After treatment, the carbon cloth is cleaned and dried to obtain the acidified carbon cloth.

5. The method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer according to claim 1, characterized in that: In step S2, in the mixed solution of nickel chloride and sodium molybdate, the mass ratio of nickel chloride to sodium molybdate is (1-3):(1-3).

6. The method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer according to claim 1, characterized in that: In step S2, the temperature of the secondary hydrothermal reaction is 100-140° C., and the time is 2-4 hours.

7. The method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer according to claim 1, characterized in that: In step S3, in the mixed atmosphere of hydrogen and argon, the volume ratio of hydrogen to argon is (5-10):(90-95).

8. The method for preparing a three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer according to claim 1, characterized in that: In step S3, in the thermal reduction annealing, the reduction temperature is 300-500° C., and the reduction time is 0.5-2 h.

9. A three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer, characterized in that: It is prepared by the method according to any one of claims 1 to 8.

10. A lithium-sulfur battery, characterized in that: A three-dimensional multi-interface heterostructure lithium-sulfur battery interlayer according to claim 9; wherein the lithium-sulfur battery has a reversible specific capacity of 700 to 800 mAh·g after 500 cycles at a voltage range of 1.7 to 2.8 V and a rate of 1C. -1 .

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