CN115000410B - Positive electrode material of lithium-sulfur battery - Google Patents

Positive electrode material of lithium-sulfur battery Download PDF

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CN115000410B
CN115000410B CN202210847080.9A CN202210847080A CN115000410B CN 115000410 B CN115000410 B CN 115000410B CN 202210847080 A CN202210847080 A CN 202210847080A CN 115000410 B CN115000410 B CN 115000410B
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titanium carbide
carbon nano
nano tube
sulfur
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CN115000410A (en
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郭容婷
李伟
刘峥
陈梦琦
郭雨婷
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Guilin University of Technology
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The invention discloses a preparation method of a carbon nano tube-titanium carbide composite porous microsphere and application thereof in a lithium-sulfur battery. The invention prepares a carbon nano tube-titanium carbide composite porous microsphere, which mainly comprises the following steps: (1) Ti (Ti) 3 AlC 2 Is etched; (2) Porous titanium carbide p-Ti 3 C 2 T x Is prepared by the steps of (1); (3) And (3) preparing the carbon nano tube-titanium carbide composite porous microspheres. The preparation method is simple and feasible, and can realize large-scale synthesis.

Description

Positive electrode material of lithium-sulfur battery
Technical Field
The invention belongs to the technical field of electrode material preparation, and particularly relates to a carbon nano tube-titanium carbide composite porous microsphere and preparation and application thereof in a lithium-sulfur battery.
Background
In lithium ion secondary battery systems, a low specific capacity positive electrode material (LiFePO 4 And LiCoO 2 Theoretical specific capacities of 170 mAh.g respectively -1 、274mAh·g -1 ) Is always a major factor limiting its development. For this reason, people have turned their eyes to new secondary battery systems in hopes of obtaining higher energy density. Among the currently known cathode materials, sulfur has a high specific capacity (1675 mAh. G -1) Compared with common lithium ion battery anode materials (lithium cobaltate, lithium manganate, lithium iron phosphate and the like), the theoretical energy density of the Li/S battery formed by the lithium metal anode is 3-5 times that of the traditional lithium ion battery. The content of elemental sulfur is very rich, and the theoretical energy density of the lithium sulfur battery is 2600 Wh.kg -1 Is much higher than that of a common lithium ion battery. Therefore, a lithium sulfur (Li-S) system is considered to be useful for next-generation secondary batteries.
As early as sixties in the last century, ulam and Herbat et al proposed the concept of Li-S batteries using sulfur as the positive electrode material, with a theoretical specific capacity of 1675mAh g-1 being very high. The Li-S battery has mainly the advantages: (1) The elementary sulfur has rich reserves in the earth, low price and environmental protection; (2) The theoretical specific capacity of the positive electrode material and the theoretical specific energy of the battery are higher, which respectively reach 1675mAh g-1 and 2600Wh kg-1, and are far higher than the capacity of the lithium cobalt oxide battery widely applied in commerce;(3) Lithium is used as the negative electrode, and the specific capacity of the negative electrode can reach 3860 mAh.g < -1 >. Large volume expansion (80%) due to complete conversion reaction of sulfur with lithium ions during discharge, and low conductivity of elemental sulfur (5×10) -30 S cm -1 ) Resulting in poor electrochemical performance. The most important problem to be solved is the shuttle effect, i.e. the lithium polysulfide (LPS, li 2 S x 4.ltoreq.x.ltoreq.8) is soluble in aprotic solvents used in lithium sulfur batteries, the negatively charged LPS is easily moved towards the Li anode under the action of an applied electric field, so that the ions re-oxidized from the LPS cannot return to the cathode, resulting in loss of active species, which in turn leads to severe capacity fade and poor rate performance. To overcome these disadvantages, many studies have been made, and there have been attempted methods: (1) Preparing C@S composite material by design using mixing, impregnating and constraining methods, (2) using a multifunctional binder; (3) improving the separator (interlayer); (4) A specially formulated electrolyte is used to inhibit the shuttle mechanism. The literature reports that the composite material obtained by loading elemental sulfur with graphene, conductive polymer or metal oxide as a carrier captures the dissolved LPS in a diffusion barrier layer of the carrier material through physical/chemical adsorption, and has a certain function of inhibiting the shuttle effect, however, the materials cannot completely overcome the defects in the lithium-sulfur battery.
MXene is a new type of two-dimensional (2D) carbide and/or nitride found by Naguib et al in 2011. These 2D materials are called MXene because they are obtained by selectively etching a (group 3 or 4 element) in the MAX phase of the precursor in an acid (HF acid) and an organic solvent. MXnes has the general formula Mn+1XnTx, where M represents an early transition metal, X represents C or N, tx represents certain chemical groups, e.g. during etching of Ti 3 AlC 2 T x And surface groups such as-O, -OH, and-F of aluminum atoms are replaced. MXene has unique properties such as high metal conductivity>5000S·cm -1 ) And is environmentally friendly. In addition, the MXene developed can be tuned to various surface functionalities depending on its application needs, increasing its versatility.
Lithium sulfur batteries (Li-S) are considered to be a promising energy storage system because of their high energy density and low cost, but they suffer from the most complex problems of shuttling effects of soluble polysulfides, etc., resulting in rapid capacity fade, severe self-discharge, low energy efficiency, and poor cycling stability. The use of nanostructured materials as sulfur carriers is a common method of mitigating polysulfide shuttling. The excellent electronic properties, electrochemical properties, optical properties and mechanical properties exhibited by the MXees material enable the MXees material to be widely applied to the fields of energy storage, flexible electronics, hydrogen storage and the like. Studies also show that the MXees material layers are easy to stack, the specific surface area and ion adsorption sites of the materials are reduced, the stacking can further block the migration of ions, the specific capacity and the rate performance of the MXees as electrode materials are greatly influenced, but due to the high conductivity and the excellent electrochemical properties, and people are striving to improve the defects of the MXees at present, the MXees are promising as the cathode materials of the lithium sulfur batteries.
The invention prepares a novel CNT/p-Ti 3 C 2 T x The MXene composite porous microsphere is based on the advantages of the MXene material, and CNTs are added simultaneously, so that the collapse and stacking defects of the lamellar structure of the MXene material are prevented by utilizing the nucleation effect of the carbon nano tube, and the CNTs can also enhance the conductivity of the composite porous microsphere. The invention aims to utilize CNT/p-Ti 3 C 2 T x The MXene composite porous microsphere solves the current problems of the lithium-sulfur battery positive electrode material, and has important significance for promoting the development of the lithium-sulfur battery positive electrode material.
Disclosure of Invention
The invention aims to provide a carbon nano tube-titanium carbide composite porous microsphere and a preparation method thereof. The invention relates to a method for preparing a carbon nano tube-titanium carbide composite porous micro-tube, which comprises the following steps:
(1)Ti 3 AlC 2 is etched: in a fume hood, 120mL HF and 6g Ti were taken 3 AlC 2 Ti is mixed with 3 AlC 2 Slowly adding into a plastic beaker filled with HF, continuously stirring under an oil bath at 35 ℃ for 24 hours to obtain a mixture after reaction;
(2) Porous titanium carbide p-Ti 3 C 2 Preparation of Tx: transferring the reacted mixture obtained in the step (1) into a centrifuge tube, centrifuging at 3500r min-1 for 8min, washing the obtained precipitate with deionized water until the pH of the supernatant is nearly neutral, adding 15-25mL deionized water into the washed precipitate, performing ultrasonic treatment for 6-8h, centrifuging at 4000r min-1 for 30min, and collecting the upper dark green liquid to obtain a few Ti layers 3 C 2 T x Freeze drying the suspension to obtain porous titanium carbide p-Ti 3 C 2 T x A powder;
(3) Preparation of carbon nano tube-titanium carbide composite porous microspheres: weighing 2g of porous titanium carbide p-Ti obtained in the step (2) according to the mass ratio of 1:1 3 C 2 T x Adding the powder and 2g of MWCNT (multi-wall carbon nano tube) into 40mL of ethanol respectively, stirring for 1h, performing ultrasonic treatment for 2h, uniformly mixing, and spraying to dry by a spray dryer to obtain CNT-titanium carbide composite porous microsphere powder CNT/p-Ti 3 C 2 T x 。
In the preparation method of the carbon nano tube-titanium carbide composite porous microsphere, the carbon nano tube CNT is multi-wall carbon nano tube MWCNT, the diameter of the carbon nano tube CNT is 30-50nm, the length of the carbon nano tube CNT is 10-20 mu m, and the titanium carbide is porous titanium carbide p-Ti 3 C 2 T X 。
It is another object of the present invention to provide the use of the carbon nanotube-titanium carbide composite porous micro-particles of the present invention.
A large number of electrochemical performance tests prove that the carbon nano tube-titanium carbide composite porous microsphere prepared by the invention can be used as a sulfur carrier and applied to a positive electrode material of a lithium sulfur battery, and can improve the specific capacity, the multiplying power performance and the cycle life of the positive electrode material.
Based on the previous study on lithium sulfur battery, the invention uses MXene material as the sulfur carrier of the lithium sulfur battery, uses the lamellar structure of MXene, uses carbon nano tube as the core, and combines the carbon nano tube by ultrasonic stripping, freeze drying and spray drying to obtain the CNT/p-Ti 3 C 2 T x MXene composite porous microsphere which can be used as the sulfur carrier and can enhance physical barrier and chemical absorption of polysulfideThe auxiliary capacity reduces the dissolution shuttle of lithium polysulfide and relieves the volume expansion effect of the sulfur anode. Proposed CNT/p-Ti 3 C 2 T x The preparation method of the MXene composite porous microsphere is simple and feasible, and can realize large-scale synthesis.
Drawings
FIG. 1CNT/p-Ti 3 C 2 SEM and EDS images of TxMXene composite porous microsphere preparation process (FIG. 1 (a) untreated Ti therein 3 AlC 2 The method comprises the steps of carrying out a first treatment on the surface of the (b) Etched Ti 3 C 2 T x The method comprises the steps of carrying out a first treatment on the surface of the (c, d) less porous Ti 3 C 2 T x The method comprises the steps of carrying out a first treatment on the surface of the (e) Less porous Ti obtained after ultrasound 3 C 2 T x A dispersion; (f) Microspheroidal CNT/p-Ti 3 C 2 T x The method comprises the steps of carrying out a first treatment on the surface of the (g) Sulfur-composited CNT/p-Ti 3 C 2 T x /S)
FIG. 2CNT/p-Ti containing 3 C 2 T x MXene (PMC) composite porous microsphere sulfur-carrying positive electrode material and Ti 3 C 2 T x MXene (M) sulfur-carrying positive electrode material Nyquist diagram
FIG. 3 CNT/p-Ti containing 3 C 2 T x MXene (PMV) composite porous microsphere sulfur-carrying positive electrode material and Ti 3 C 2 T x Ratio performance comparison chart of MXene (M) sulfur-loaded positive electrode material under different ratios
FIG. 4 CNT/p-Ti containing 3 C 2 T x MXene (PMC) composite porous microsphere sulfur-carrying positive electrode material and Ti 3 C 2 T x Cycle performance comparison chart of MXene (PMC) sulfur-loaded positive electrode material under different multiplying powers
Detailed Description
The following examples are further illustrative of the invention and are not intended to be limiting thereof.
Example 1 preparation of nanotube-titanium carbide composite porous microspheres.
(1)Ti 3 AlC 2 Is etched by (a)
In a fume hood, 120mL HF and 6g Ti were taken 3 AlC 2 Ti is mixed with 3 AlC 2 Slowly adding into plastic beaker filled with HF, stirring under oil bath, and heatingThe temperature was 35℃and the time was 24 hours, to obtain a post-reaction mixture.
(2) Porous titanium carbide p-Ti 3 C 2 Tx preparation
Transferring the reacted mixture obtained in the step (1) into a centrifuge tube, wherein the centrifugation speed is 3500rmin -1 Centrifuging for 8min, washing the obtained precipitate with deionized water until the pH of supernatant is near neutral, adding 20mL deionized water into the washed precipitate, performing ultrasonic treatment for 7h, and standing for 4000r min -1 Centrifuging for 30min, collecting the upper layer dark green liquid to obtain less Ti layer 3 C 2 T x Freeze drying the suspension to obtain porous titanium carbide p-Ti 3 C 2 T x And (3) powder.
(3) Preparation of carbon nano tube-titanium carbide composite porous microsphere
Weighing 2g of porous titanium carbide p-Ti obtained in the step (2) according to the mass ratio of 1:1 3 C 2 T x Adding the powder and 2g of MWCNT (multi-wall carbon nano tube) into 40mL of ethanol respectively, stirring for 1h, performing ultrasonic treatment for 2h, uniformly mixing, and spraying to dry by a spray dryer to obtain CNT-titanium carbide composite porous microsphere powder CNT/p-Ti 3 C 2 T x 。
FIG. 1 is an SEM image and an EDS image of a carbon nanotube-titanium carbide composite porous microsphere after preparation and sulfur loading. As can be seen from a comparison of FIG. 1 (a) with FIG. 1 (b), ti was initially present 3 AlC 2 Is in the form of stacked blocks, and is etched by HF to remove Ti 3 AlC 2 After Al in (C), clearly see Ti 3 AlC 2 Ti becomes accordion-like in FIG. 1 (b) 3 C 2 T x 。Ti 3 C 2 T x Performing ultrasonic treatment to obtain Ti 3 C 2 T x The dispersion (fig. 1 (e)) was observed to have a tyndall effect; after the dispersion liquid is freeze-dried, the Ti with less porous layers is successfully obtained 3 C 2 T x (i.e. p-Ti 3 C 2 T x ) As shown in fig. 1 (c) and 1 (d). The porous structure can effectively relieve the volume expansion effect of the sulfur anode. Fully mixing with alcohol solution of carbon nano tube and spray drying to obtain microsphereCNT/p-Ti of (c) 3 C 2 T x (FIG. 1 (f)). Elemental map display of EDS (FIG. 1 (g)), S and CNT/p-Ti 3 C 2 T x Good adhesion of the material, and CNT/p-Ti 3 C 2 T x Ti, C and S in/S are uniformly distributed, indicating CNT/pTi 3 C 2 T x The material has strong sulfur loading capacity, can strengthen physical limitation and chemical adsorption of polysulfide, and enhances the conductivity of S, thereby improving the electrochemical performance of the battery.
EXAMPLE 2CNT/p-Ti 3 C 2 T x MXene/S electrochemical performance test.
With Ti 3 C 2 T x MXene/S as a comparison, the sulfur loading process is as follows: ti is mixed with 3 C 2 T x MXene or CNT/p-Ti 3 C 2 T x MXene and sulfur powder are mixed according to the mass ratio of 1:4, alcohol is added dropwise under an infrared drying oven, and the mixture is ground uniformly by an agate mortar. Placing the obtained mixture in a tube furnace, and burning at 155 deg.C under Ar atmosphere for 12 hr to obtain Ti 3 C 2 T x MXene/S or CNT/p-Ti 3 C 2 T x The MXene/S electrochemical performance test steps are as follows:
(1)CNT/p-Ti 3 C 2 T x preparation of MXene/S positive plate
0.07g of a composite material (CNT/p-Ti was weighed out 3 C 2 T x MXene) was mixed with 0.02g of acetylene black and 0.0.1g of polyvinylidene fluoride (PVDF) using N-methyl-2-pyrrolidone (NMP) as a solvent, uniformly ground into a slurry in an agate grinding bowl, then coated on an aluminum foil using the aluminum foil as a current collector, and vacuum-dried at 80 ℃ for 12 hours.
(2) Assembling the prepared anode material into a battery in a vacuum glove box (the volume fraction of oxygen is less than 0.1ppm, and the volume fraction of water is less than 0.1 ppm), taking a lithium sheet as a negative electrode, and sequentially putting the anode sheet, a diaphragm, the lithium sheet, a gasket and an elastic sheet into a battery shell; and (5) dropwise adding a proper amount of electrolyte, sealing by a sealing machine, and assembling the CR2032 button battery for later use.
(3) Electrochemical alternating current impedance spectroscopy (EIS) test
FIG. 2 is a schematic view ofCNT/p-Ti 3 C 2 T x Composite material of/S (PMC) and Ti 3 C 2 T x Nyquist plot of/S (hereinafter M) material. As can be seen from fig. 2, two semicircles are shown in the high and medium frequency regions and a diagonal line is shown in the low frequency region. The first semicircle in the high frequency range represents the interfacial resistance of the solid electrolyte interfacial film (SEI) or the resistance of lithium ions flowing through the SEI (Rs). The semicircle of the intermediate frequency represents the charge transfer resistance (Rct) between the SEI and the electrolyte. The diagonal line (Warburg impedance) reflects the diffusion of lithium ions in the electrode. Analysis of FIG. 2 shows that CNT/p-Ti 3 C 2 T x Ac impedance rct=9.7Ω of the/S (PMC) composite material, much smaller than Ti 3 C 2 Tx (M) indicates a faster kinetics of the charge transfer process. This can be attributed to the addition of the multi-wall CNT, which enhances the conductivity of the composite porous microsphere, facilitates the charge transfer of the electrode itself, and can reduce the resistance value of the PMC cathode material and increase its conductivity.
(4) Rate capability test
FIG. 3 is a CNT/p-Ti 3 C 2 T x Composite material of/S (PMC) and Ti 3 C 2 T x The material/S (hereinafter referred to as M) was subjected to a rate performance test. As can be seen from FIG. 3, the PMC positive electrode showed excellent rate performance with respect to continuous change of current density, and when tested at current densities of 0.1, 0.2, 0.3, 0.5, 1, 2, 1, 0.5, 0.3, 0.2, 0.1C, the PMC electrode provided 889.06, 746.62, 656.28, 600.47, 519.45, 601.85, 673.75mA h.g, respectively -1 Is excellent in specific discharge capacity. Furthermore, after cycling the current density back to 0.1C, the PMC electrode was still able to recover 673.75 mAh.g -1 Is stable and has high specific capacity. This is in sharp contrast to M-electrodes, which have specific discharge capacities of only 615.37, 540.93, 476.90, 401.59, 181.77, 318.11, 407.03, 496.70, and 544.81 mAh.g, respectively, at the same test rates -1 Only a lower specific capacity is shown. These test data clearly demonstrate that CNT/p-Ti 3 C 2 T x The (PMC) electrode material has better rate capability and cycling stability, further illustrating the advantages and necessity of CNT addition.
(4) Cycle performance test
FIG. 4 (a) is a graph showing the results of constant current charge and discharge performance test of CNT/p-Ti3C2Tx (PMC) and Ti3C2Tx (M) at a current density of 0.1C, FIG. 4 (b) is a graph showing the comparison of the cycle performance of PMC and M at a current of 0.1C, and 200 cycles at a large current density of 1C. From the discharge curve in fig. 4 (a), it can be seen that PMC starts to appear at 2.1 and 2.3V as two distinct discharge plateaus, which are the processes of sulfur reduction to polysulfide and polysulfide conversion to insoluble long chain polysulfide compounds, respectively. As can be seen from FIG. 4 (b), the initial discharge capacity of the PMC composite material was 631.51mA hg -1 Can be kept at 390.91 mAh.g after 200 times of circulation -1 The capacity fade rate is small. As can be seen from FIG. 4 (c), the discharge capacities of the PMC composite materials in the first four cycles were 915.51, 913.65, 912.05, 902.18 mAh.g, respectively -1 Furthermore, during cycling, the voltage difference between the charge and discharge plateau of the PMC composite is stable, which in turn indicates a decrease in resistance in the active material during cycling, li + The ion diffusivity is enhanced. As can be seen from FIG. 4 (C), the specific discharge capacity of the PMC material after 20 cycles at a current density of 0.1C can be maintained at 900 mAh.g -1 Up and down, accounting for 90% of its initial specific capacity, PMC consistently showed higher and better coulombic efficiency during these 20 cycles.

Claims (1)

1. A lithium sulfur battery positive electrode material comprises sulfur-loaded carbon nano tube-titanium carbide composite porous microspheres, wherein the carbon nano tube-titanium carbide composite porous microspheres comprise multi-wall carbon nano tube MWCNT and porous titanium carbide p-Ti with diameters of 30-50nm and lengths of 10-20 mu m 3 C 2 T X The sulfur-loaded carbon nano tube-titanium carbide composite porous microsphere is prepared by the following steps:
（1）Ti 3 AlC 2 is etched: in a fume hood, 120mL HF and 6g Ti were taken 3 AlC 2 Ti is mixed with 3 AlC 2 Slowly adding into plastic beaker containing HF, stirring under oil bath at 35deg.C for 24hObtaining a post-reaction mixture;
(2) Porous titanium carbide p-Ti 3 C 2 T x Is prepared from the following steps: transferring the mixture obtained in the step (1) into a centrifuge tube, wherein the centrifugation speed is 3500 r.min -1 Centrifuging for 8min, washing the obtained precipitate with deionized water until the pH of supernatant is close to neutral, adding 15-25mL deionized water into the washed precipitate, performing ultrasonic treatment for 6-8 hr, and treating at 4000 r.min -1 Centrifuging for 30min, collecting the upper layer dark green liquid to obtain less Ti layer 3 C 2 T x Freeze drying the suspension to obtain porous titanium carbide p-Ti 3 C 2 T x A powder;
(3) Carbon nano tube-titanium carbide composite porous microsphere CNT/p-Ti 3 C 2 T x Is prepared from the following steps: weighing 2g of porous titanium carbide p-Ti obtained in the step (2) according to the mass ratio of 1:1 3 C 2 Adding Tx powder and 2g multi-wall carbon nanotube MWCNT into 40mL ethanol respectively, stirring for 1h, ultrasonic treating for 2h, mixing uniformly, and spray drying with spray dryer to obtain carbon nanotube-titanium carbide composite porous microsphere powder CNT/p-Ti 3 C 2 T x ；
(4) Preparing the sulfur-loaded carbon nano tube-titanium carbide composite porous microsphere, namely preparing the carbon nano tube-titanium carbide composite porous microsphere CNT/p-Ti obtained in the step (3) 3 C 2 T x Mixing with sulfur powder according to a mass ratio of 1:4, dropwise adding alcohol under an infrared drying oven, grinding uniformly with an agate mortar to obtain a mixture, placing the mixture into a tube furnace, and burning at 155 ℃ in Ar atmosphere for 12h to obtain sulfur-loaded carbon nano tube-titanium carbide composite porous microsphere CNT/p-Ti 3 C 2 T x /S。
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WO2021145557A1 (en) * 2020-01-15 2021-07-22 한국과학기술원 Method for improving charging/discharging speed characteristics of mxene and carbon nanotube-based energy storage device
CN111900403A (en) * 2020-07-30 2020-11-06 广州特种承压设备检测研究院 Sulfur/MXene/graphene composite material and preparation method and application thereof
CN112072126A (en) * 2020-08-31 2020-12-11 华南理工大学 Mxene flexible self-supporting lithium-air battery positive electrode material, Mxene flexible composite film and preparation method thereof
CN112263974A (en) * 2020-11-24 2021-01-26 山东大学 Spray drying method for preparing Ti3C2Method for Tx/carbon black composite microsphere
CN113571841A (en) * 2021-07-22 2021-10-29 哈尔滨师范大学 Lithium-sulfur battery composite diaphragm and preparation method thereof

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