Mold spore carbon / metal carbide-plasma reduced graphene oxide fiber free-standing material, method of making and use thereof

Abstract

The present invention discloses a mold spore carbon / metal carbide-plasma reduced graphene oxide fiber self-supporting material, a preparation method thereof, and an application thereof as a self-supporting flexible lithium-sulfur battery positive electrode material. The mold spore carbon / metal carbide particles are uniformly spun into a graphene oxide fiber non-woven fabric material by wet spinning technology. The reduced graphene oxide fiber non-woven fabric skeleton has good electrical conductivity; the nano-sulfur particles coated inside the reduced graphene oxide fiber can provide space for the volume expansion of sulfur during the reaction. The polar and catalytic metal carbide has a strong adsorption effect on polysulfides, which can inhibit the "shuttle effect" of polysulfides and catalyze the conversion of polysulfides. Therefore, the prepared composite material has excellent electrical conductivity and flexibility, and as a self-supporting lithium-sulfur battery positive electrode material, it has a high specific capacity and excellent cycle rate performance.

Description

TECHNICAL FIELD

[0001] The method relates to a novel lithium-sulfur battery positive electrode material, and particularly relates to a mold spore carbon / metal carbide-plasma reduced graphene oxide fiber self-supporting material, a preparation method thereof and application of the material as a self-supporting flexible lithium-sulfur battery positive electrode material. BACKGROUND

[0002] With the development of science and technology, flexible wearable electronic devices are emerging, foldable smart phones, flexible sensors, human-computer interaction and other devices have become the forefront of scientific research. At present, the energy density of commercial lithium ion batteries has been difficult to meet the demand of flexible devices for electrical energy storage. In order to further promote the commercial application of wearable devices in the future, the development of a flexible storage system with high energy density has become the key to the development of intelligent wearable electronic devices. Lithium-sulfur batteries have a high theoretical energy density (2600 Wh kg -1 ) and a high theoretical specific capacity (1675 mAh g -1 ). In addition, sulfur is widely available in nature and has low cost and no toxic pollution. Therefore, lithium-sulfur batteries based on the multi-electron electrochemical conversion reaction of sulfur and lithium have become a research hotspot and are considered to be one of the most promising flexible new energy systems.

[0003] In order to withstand bending, twisting, stretching and folding and other battery deformations, the selection of the base material plays a crucial role. Compared with the non-flexible lithium-sulfur battery electrode formed by the traditional coating method, the flexible electrode material does not add adhesives and metal supports, the conductivity is greatly improved, the proportion of sulfur in the entire electrode is increased, and the flexible electrode material has a certain toughness and can relieve the volume expansion of sulfur during the cycle process. Graphene is a new two-dimensional material composed of single-layer carbon atoms, has extremely high electrical conductivity, strong mechanical properties and low density, and is an excellent lithium-sulfur battery positive electrode material, but is difficult to prepare. As an important derivative of graphene, graphene oxide has a large specific surface area and rich oxygen-containing functional groups, which endow it with excellent chemical compatibility and operability. However, a large number of oxygen-containing functional groups seriously damage the electrical conductivity of graphene oxide, which cannot be directly used as a lithium-sulfur battery positive electrode material. The preparation of graphene by reducing graphene oxide has become an important way for low-cost and macro-scale preparation of graphene, and has great significance for promoting the macro-scale application of graphene. At present, the method for reducing graphene oxide has the disadvantages of high energy consumption, high cost and toxic reagents. Therefore, it is urgent to develop an efficient, low-cost, pollution-free and low-temperature reduction method suitable for the reduction of graphene oxide film to prepare a flexible lithium-sulfur battery positive electrode material with high performance. SUMMARY

[0004] The present application aims at the problems in the background art, and provides a mold spore carbon / metal carbide-plasma reduced graphene oxide fiber self-supporting material, a preparation method thereof and an application thereof as a self-supporting flexible lithium-sulfur battery positive electrode material. Specifically, a synthesized mold spore carbon / metal carbide material is directly spun into an oxidized graphene non-woven fabric material through a wet spinning method. The oxidized graphene non-woven fabric material is light in weight and has good mechanical properties, and endows the electrode material with good flexibility; and the oxidized graphene non-woven fabric material is rapidly reduced through a plasma technology, significantly improves the conductivity of the film, and can promote ion and electron transmission in the reaction process, and is an excellent sulfur carrier material. The mold spore carbon / metal carbide material with a large specific surface area provides a large number of sulfur storage sites, and the good conductivity of the metal carbide can effectively promote electron transfer in the electrode reaction process, and has a significant catalytic effect on the conversion of polysulfides. Therefore, the prepared mold spore carbon / metal carbide-plasma reduced graphene fiber self-supporting material has excellent conductivity and flexibility, and as a self-supporting lithium-sulfur battery positive electrode material, has high specific capacity and excellent cycle rate performance.

[0005] A mold spore carbon / metal carbide-plasma reduced graphene fiber material as an excellent self-supporting flexible lithium-sulfur battery positive electrode material is composed of a reduced graphene fiber skeleton and mold spore carbon / metal carbide particles uniformly doped therebetween. The mold spore carbon / metal carbide particles are uniformly dispersed in a three-dimensional reduced graphene fiber non-woven fabric composite material. Through high-temperature steam sulfur infiltration, a sulfur-mold spore carbon / metal carbide-plasma reduced graphene fiber material is prepared.

[0006] A preparation method of a mold spore carbon / metal carbide-plasma reduced graphene fiber material, comprising the following steps:

[0007] (1) The mold spores are subjected to high-temperature heat treatment in argon, the heating temperature is 600-1000℃, the heating time is 1-5 hours, and the temperature rising rate is 1-10℃ / min -1 , and mold spore carbon material is obtained after cooling;

[0008] (2) The mold spore carbon material obtained in step (1) is soaked in an ethanol solution containing a metal alcohol or ester solvent, transferred to a reaction kettle and treated through a simple solvothermal method, the treatment temperature is 100-300℃, the treatment time is 10-24 hours, and after suction filtration and drying, a mold spore carbon / metal oxide composite material is prepared;

[0009] (3) the mold spore carbon / metal oxide composite material obtained in step (2) is subjected to high-temperature carbon thermal treatment in argon, the heating temperature is 700-1500 DEG C, the heating time is 1-5 hours, and the temperature rising rate is 1-10 DEG C / min -1 , and a mold spore carbon / metal carbide composite material is obtained after cooling;

[0010] (4) the mold spore carbon / metal carbide composite material obtained in step (3) is added into a graphene oxide solution, a dispersion is prepared after wet spinning, and the mold spore carbon / metal carbide-graphene oxide fiber self-supporting material is obtained after being subjected to suction filtration and drying;

[0011] (5) the mold spore carbon / metal carbide-graphene oxide fiber self-supporting material obtained in step (4) is placed in a plasma discharge chamber, vacuumized, and a gas is introduced, the plasma flow of the gas is generated in the discharge chamber by adjusting the gas flow and the radio frequency power, the plasma flow of the gas directly acts on the surface of the mold spore carbon / metal carbide-graphene oxide fiber self-supporting material, and the mold spore carbon / metal carbide-plasma reduced graphene oxide fiber self-supporting material is obtained after a certain time;

[0012] (6) the mold spore carbon / metal carbide-plasma reduced graphene oxide fiber self-supporting material obtained in step (5) and nano sulfur are placed in a quartz tube, vacuum sealing is performed, and the sulfur-mold spore carbon / metal carbide-plasma reduced graphene oxide fiber material is obtained by steam sulfurization at high temperature;

[0013] The mold spore carbon / metal carbide material synthesized by the wet spinning method is directly spun into the graphene oxide non-woven fabric material, the graphene oxide non-woven fabric material is light in quality and has good mechanical properties, the electrode material is endowed with good flexibility, the graphene oxide non-woven fabric material is rapidly reduced by the plasma technology, the conductivity of the film is significantly improved, the ion and electron transmission in the reaction process is promoted, and the sulfur carrier material is excellent. The mold spore carbon / metal carbide material with a large specific surface area provides a large number of sulfur storage sites, the good conductivity of the metal carbide can effectively promote the electron transfer in the electrode reaction process, and the metal carbide has a significant catalytic effect on the conversion of polysulfides. Therefore, the mold spore carbon / metal carbide-plasma reduced graphene oxide fiber self-supporting material has excellent conductivity and flexibility, as a self-supporting lithium-sulfur battery positive electrode material, has high specific capacity and excellent cycle rate performance.

[0014] Further, in step (1), the mold spores are Aspergillus spores, Penicillium spores, Trichoderma spores, Mucor spores and Rhizopus spores;

[0015] In step (2), the metal alcohol or ester solvent is one or more of a metal nickel-containing alcohol or ester solvent, a metal cobalt-containing alcohol or ester solvent, a metal iron-containing alcohol or ester solvent, a metal manganese-containing alcohol or ester solvent, and a metal titanium-containing alcohol or ester solvent;

[0016] In step (3), the metal carbide is one or more of nickel carbide, cobalt carbide, iron carbide, manganese carbide, and titanium carbide;

[0017] In step (5), the gas is one or more of hydrogen, argon, methane, and ammonia;

[0018] In step (5), the flow rate of the gas is 5-100 sccm;

[0019] In step (5), the reaction conditions are as follows: the radio frequency power is 10-500 W, the vacuum degree is 5-30 Pa, and the reaction time is 1-30 minutes;

[0020] In step (6), the ratio of the mold spore carbon / metal carbide-plasma reduced graphene oxide fiber and nano sulfur is 1:1-1:10;

[0021] In step (6), the high-temperature treatment temperature is 400-500 DEG C, and the treatment time is 5-30 hours;

[0022] In the mold spore carbon / metal carbide-plasma reduced graphene oxide fiber non-woven fabric composite material, the fiber diameter is 50-200 microns (further preferably 70-120 microns), the mold spore carbon / metal carbide particle diameter is 0.5-10 microns (further preferably 1-2 microns), and the metal carbide particle size is 5-50 nm (further preferably 10-20 nm);

[0023] In the sulfur-mold spore carbon / metal carbide-plasma reduced graphene oxide fiber non-woven fabric composite material, the mass percentage of nano sulfur is 20% to 90%, and the mass percentage of carbon is 10% to 80%.

[0024] The sulfur-mold spore carbon / metal carbide-plasma reduced graphene oxide fiber non-woven fabric composite material has the advantages of high sulfur loading, good conductivity, high flexibility, effective absorption of polysulfides, and catalytic conversion of polysulfides when used as a self-supporting lithium-sulfur battery positive electrode material, and the assembled lithium-sulfur battery has high specific capacity, high rate performance, and long cycle life, and has wide application prospects in wearable devices, medical implantable devices, electronic skin, and intelligent electronic fabrics.

[0025] In summary, the present application has the following advantages:

[0026] In the present application, mold spore carbon / metal carbide is spun into graphene oxide fiber non-woven material by wet spinning technology. Compared with ordinary S / C composite positive electrode, it has the advantages of high sulfur loading, high flexibility and simple preparation process. The graphene oxide non-woven material is light in weight and has good mechanical properties, which endows the electrode material with good flexibility;

[0027] The graphene oxide fiber is reduced by plasma generated by gas. As a kind of high-energy ion group, plasma can quickly and efficiently reduce graphene oxide fiber at low temperature. The cross-linked reduced graphene oxide layers form an excellent conductive network, which can promote the transmission of ions and electrons in the reaction process. The nano sulfur particles coated inside the reduced graphene oxide fiber can provide space for the volume expansion of sulfur in the reaction process and inhibit the release of soluble polysulfides. At the same time, the mold spore carbon with large specific surface area provides sufficient sulfur loading sites for sulfur. The metal carbide with polarity and catalytic effect has strong adsorption effect on polysulfides, which can inhibit the "shuttle effect" of polysulfides and catalyze the conversion of polysulfides. Therefore, the prepared sulfur-mold spore carbon / metal carbide-plasma reduced graphene fiber non-woven composite material has excellent conductivity and flexibility, and as a self-supporting lithium-sulfur battery positive electrode material, it has high specific capacity and excellent cycle rate performance.

[0028] The mold spore carbon / metal carbide-plasma reduced graphene fiber self-supporting material has excellent conductivity and flexibility, and as a self-supporting lithium-sulfur battery positive electrode material, it has high specific capacity and excellent cycle rate performance, which is expected to be widely used in the field of flexible energy storage devices. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a scanning electron microscope image of the mold spore carbon / metal carbide prepared in Example 1.

[0030] Figure 2 It is a scanning electron microscope image of the mold spore carbon / metal carbide-plasma reduced graphene fiber non-woven composite material prepared in Example 1.

[0031] Figure 3 It is a cross-sectional scanning electron microscope image of the mold spore carbon / metal carbide-plasma reduced graphene fiber non-woven composite material prepared in Example 1.

[0032] Figure 4 It is a mechanical property diagram of the mold spore carbon / metal carbide-plasma reduced graphene fiber non-woven composite material prepared in Example 1.

[0033] Figure 5Cycling performance chart of sulfur-mold spore carbon / metal carbide-plasma reduced graphene oxide fiber non-woven fabric composite material prepared in Example 1 as a positive electrode material of a lithium-sulfur battery. DETAILED DESCRIPTION

[0034] The application will be described in detail below with reference to examples, but the application is not limited to the examples.

[0035] Example 1

[0036] 5g of Aspergillus oryzae spores were subjected to high-temperature heat treatment in argon, the heating temperature was 800℃, the heating time was 2 hours, and the temperature rising rate was 5℃ / min -1 , and after cooling, Aspergillus oryzae spore carbon material was obtained; the Aspergillus oryzae spore carbon was then soaked in a 60mL ethanol solution containing 2g of titanium isopropylate, transferred to a 100mL reaction kettle, and treated by a simple solvothermal method, the treatment temperature was 200℃, the treatment time was 12 hours, and after suction filtration and drying, Aspergillus oryzae spore carbon / titanium oxide composite material was prepared; the obtained Aspergillus oryzae spore carbon / titanium oxide composite material was subjected to high-temperature carbon thermal treatment in argon, the heating temperature was 1200℃, the heating time was 3 hours, and the temperature rising rate was 5℃ / min -1 , and after cooling, Aspergillus oryzae spore carbon / titanium carbide composite material was obtained; the material was added to a graphene oxide solution, a dispersion was prepared, and wet spinning was performed, and after suction filtration and drying, Aspergillus oryzae spore carbon / titanium carbide-graphene oxide fiber self-supporting material was obtained; the material was placed in a plasma discharge chamber, vacuumized, and hydrogen gas with a flow rate of 20sccm was introduced, the radio frequency power was adjusted to 80W by opening the radio frequency power source and controlling the panel, and the vacuum degree in the device was controlled to 20Pa. After ignition, hydrogen plasma was directly applied to the surface of the Aspergillus oryzae spore carbon / titanium carbide-graphene oxide fiber self-supporting material, and after 1 minute of treatment, the radio frequency power source was turned off, and Aspergillus oryzae spore carbon / titanium carbide-plasma reduced graphene oxide fiber self-supporting material was obtained; then, 1:5 mass ratio of Aspergillus oryzae spore carbon / titanium carbide-plasma reduced graphene oxide fiber self-supporting material and nano sulfur were placed together in a quartz tube, vacuum sealing was performed, and steam sulfurization was performed at a high temperature of 400℃ for 12 hours to obtain sulfur-Aspergillus oryzae spore carbon / titanium carbide-plasma reduced graphene oxide fiber material.

[0037] The scanning electron microscope chart of Aspergillus oryzae spore carbon / titanium carbide prepared in Example 1 is shown in Figure 1 ; the scanning electron microscope chart of Aspergillus oryzae spore carbon / titanium carbide-plasma reduced graphene oxide fiber non-woven fabric composite material prepared in Example 1 is shown in Figure 2 ; and the cross-sectional scanning electron microscope chart of Aspergillus oryzae spore carbon / titanium carbide-plasma reduced graphene oxide fiber non-woven fabric composite material prepared in Example 1 is shown in Figure 3As shown; the mechanical properties of the Aspergillus oryzae spore carbon / titanium carbide-plasma reduced graphene oxide fiber non-woven fabric composite material prepared in Example 1 are shown in FIG. Figure 4 As shown in Example 1, the sulfur-Aspergillus oryzae spore carbon / titanium carbide-plasma reduced graphene oxide fiber non-woven fabric composite material as a lithium sulfur battery positive electrode material cycle performance diagram as shown in Figure 5 As shown in the figure, titanium carbide nanoparticles with a diameter of approximately 10 nm are uniformly loaded onto the Aspergillus oryzae spore carbon, which is approximately 2 μm in size. After spinning, the graphene oxide fibers are reduced using plasma, and the Aspergillus oryzae spore carbon / titanium carbide material is evenly dispersed within the reduced graphene oxide fibers. The fiber diameter of the Aspergillus oryzae spore carbon / titanium carbide-plasma-reduced graphene oxide fiber non-woven composite is 100 μm. After steam sulfurization, the sulfur-mold spore carbon / metal carbide-plasma-reduced graphene oxide fiber non-woven composite material contains 85.2% nanosulfur by weight.

[0038] Example 2

[0039] 5 g of Trichoderma spores were subjected to high temperature heat treatment in argon at a temperature of 800 °C for 2 h at a heating rate of 5 °C min -1 , and after cooling, a Trichoderma spore carbon material was obtained; the Trichoderma spore carbon was then immersed in a 60 mL ethanol solution containing 2 g of tetraisopropyl titanate, transferred to a 100 mL reactor and treated by a simple solvent thermal method at a treatment temperature of 200 ° C for 12 hours, filtered and dried to obtain a Trichoderma spore carbon / titanium oxide composite material; the obtained Trichoderma spore carbon / titanium oxide composite material was subjected to high-temperature carbon heat treatment in argon at a heating temperature of 1200 ° C for 3 hours and a heating rate of 5 ° C min -1 , after cooling, a Trichoderma spore carbon / titanium carbide composite material is obtained; the composite material is added to a graphene oxide solution to obtain a dispersion, which is then wet-spun, and after filtration and drying, a Trichoderma spore carbon / titanium carbide-graphene oxide fiber self-supporting material is obtained; the material is placed in a plasma discharge chamber, evacuated, and hydrogen gas with a gas flow rate of 20 seem is introduced, the radio frequency power is turned on, the radio frequency power is adjusted to 80 W through the control panel, and the vacuum degree in the device is controlled to 20 Pa. After ignition, hydrogen plasma directly acts on the surface of the Trichoderma spore carbon / titanium carbide-graphene oxide fiber self-supporting material. After treatment for 1 minute, the radio frequency power supply is turned off to obtain the Trichoderma spore carbon / titanium carbide-plasma reduced graphene oxide fiber self-supporting material; then the Trichoderma spore carbon / titanium carbide-plasma reduced graphene oxide fiber self-supporting material and nanosulfur in a mass ratio of 1:5 are placed together in a quartz tube, vacuum sealed, and treated at a high temperature of 400°C for 12 hours for steam sulfurization to obtain sulfur-Trichoderma spore carbon / titanium carbide-plasma reduced graphene oxide fiber material.

[0040] Example 3

[0041] 5g of Aspergillus oryzae spores were subjected to high-temperature heat treatment in argon, the heating temperature was 800℃, the heating time was 2 hours, and the heating rate was 5℃ / min -1 , and after cooling, Aspergillus oryzae spore carbon material was obtained; the Aspergillus oryzae spore carbon was then soaked in a 60mL ethanol solution containing 2g of tetrabutyl titanate, transferred to a 100mL reaction kettle, and treated by a simple solvothermal method, the treatment temperature was 200℃, the treatment time was 12 hours, and after suction filtration and drying, Aspergillus oryzae spore carbon / titanium oxide composite material was prepared; the obtained Aspergillus oryzae spore carbon / titanium oxide composite material was subjected to high-temperature carbon thermal treatment in argon, the heating temperature was 1200℃, the heating time was 3 hours, and the heating rate was 5℃ / min -1 , and after cooling, Aspergillus oryzae spore carbon / titanium carbide composite material was obtained; it was added to a graphene oxide solution, a dispersion was prepared, and wet spinning was performed, and after suction filtration and drying, Aspergillus oryzae spore carbon / titanium carbide-graphene oxide fiber self-supporting material was obtained; the material was placed in a plasma discharge chamber, vacuumized, and hydrogen gas with a flow rate of 20sccm was introduced, the radio frequency power was adjusted to 80W by opening the radio frequency power source and controlling the panel, and the vacuum degree in the device was controlled to 20Pa. After ignition, the hydrogen plasma directly acted on the surface of the Aspergillus oryzae spore carbon / titanium carbide-graphene oxide fiber self-supporting material, and after 1 minute of treatment, the radio frequency power source was turned off, and Aspergillus oryzae spore carbon / titanium carbide-plasma reduced graphene oxide fiber self-supporting material was obtained; then, 1:5 mass ratio of Aspergillus oryzae spore carbon / titanium carbide-plasma reduced graphene oxide fiber self-supporting material and nano sulfur were placed together in a quartz tube, vacuum sealing was performed, and steam sulfurization was performed at a high temperature of 400℃ for 12 hours to obtain sulfur-Aspergillus oryzae spore carbon / titanium carbide-plasma reduced graphene oxide fiber material.

[0042] Example 4

[0043] 5g of Aspergillus oryzae spores were subjected to high-temperature heat treatment in argon, the heating temperature was 800℃, the heating time was 2 hours, and the heating rate was 5℃ / min -1 , and after cooling, Aspergillus oryzae spore carbon material was obtained; the Aspergillus oryzae spore carbon was then soaked in a 60mL ethanol solution containing 2g of tetrabutyl titanate, transferred to a 100mL reaction kettle, and treated by a simple solvothermal method, the treatment temperature was 200℃, the treatment time was 12 hours, and after suction filtration and drying, Aspergillus oryzae spore carbon / titanium oxide composite material was prepared; the obtained Aspergillus oryzae spore carbon / titanium oxide composite material was subjected to high-temperature carbon thermal treatment in argon, the heating temperature was 1200℃, the heating time was 3 hours, and the heating rate was 5℃ / min -1, and the rice spore carbon / titanium carbide composite material was obtained after cooling; the rice spore carbon / titanium carbide composite material was added into a graphene oxide solution, a dispersion was prepared, and wet spinning was performed, and a rice spore carbon / titanium carbide-graphene oxide fiber self-supporting material was obtained after being subjected to suction filtration and drying; the material was placed in a plasma discharge chamber, vacuumized, and argon gas with a flow rate of 20 sccm was introduced, a radio frequency power of 80 W was adjusted by turning on the radio frequency power and controlling the panel, and the vacuum degree in the device was controlled to be 20 Pa. After ignition, the argon plasma directly acted on the surface of the rice spore carbon / titanium carbide-graphene oxide fiber self-supporting material, and after 1 minute of treatment, the radio frequency power was turned off, and a rice spore carbon / titanium carbide-plasma reduced graphene oxide fiber self-supporting material was obtained; then, the rice spore carbon / titanium carbide-plasma reduced graphene oxide fiber self-supporting material and nano sulfur with a mass ratio of 1:5 were placed together in a quartz tube, vacuum sealing was performed, and sulfur-rice spore carbon / titanium carbide-plasma reduced graphene oxide fiber material was obtained by steam sulfurization at a high temperature of 400 DEG C for 12 hours.

[0044] Performance test

[0045] The sulfur-rice spore carbon / titanium carbide-plasma reduced graphene oxide fiber material prepared in the above examples 1-4 was used as a lithium sulfur battery positive electrode, metal lithium was used as a negative electrode, and a polypropylene microporous film (Celgard 2400) was used as a separator, and a CR2025 button cell was assembled in a glove box with argon as a protective gas, and the water oxygen partial pressure was less than 0.1 ppm. Lithium bis-trifluoromethanesulfonimide (LiTFSI) was dissolved in a mixed solution of ethylene glycol dimethyl ether (DME) and 1,3-dioxolane (DOL) with a volume ratio of 1:1, and 1 wt.% of lithium nitrate (LiNO3) was added as an electrolyte. After the battery was left for 12 hours, cyclic voltammetry test (CV), electrochemical impedance spectroscopy test (EIS) and charge-discharge test were carried out at room temperature. The charge-discharge test instrument was a new Wei battery test system, and the test voltage range was relative to Li / Li + 1.7-2.8 V, the cycle performance of the battery at 0.1 C was tested, and the coulombic efficiency and rate performance test (0.1 C-5 C) were used to verify that the sulfur-rice spore carbon / titanium carbide-plasma reduced graphene oxide fiber material assembled lithium sulfur battery has excellent charge-discharge cycle performance and high rate characteristics.

[0046] The lithium sulfur battery assembled by example 1 was tested for cycle performance and coulombic efficiency at 0.1 C, and the first discharge capacity was 986.8 mA h g -1, the discharge specific capacity retention rate of the battery is 91.8% after 120 cycles, and it can be seen that the sulfur-aspergillus carbon / titanium carbide-plasma reduced graphene fiber material prepared above has high discharge capacity and good cycle stability. The lithium-sulfur battery assembled has a discharge specific capacity of 602mA h g -1 at a large current density of 5C, indicating that it has good rate performance.

[0047] This is mainly due to the cross-linked reduced graphene oxide layers in the sulfur-aspergillus carbon / titanium carbide-plasma reduced graphene fiber non-woven composite electrode material forming an excellent conductive network, which can promote ion and electron transmission in the reaction process; the nanosulfur particles are coated inside the reduced graphene fiber to provide space for the volume expansion of sulfur in the reaction process and inhibit the shedding of soluble polysulfides. At the same time, the large specific surface area of the mold spore carbon provides sufficient sulfur loading sites for sulfur. The polar and catalytic metal carbide has a strong adsorption effect on polysulfides, which can inhibit the "shuttle effect" of polysulfides and catalyze the conversion of polysulfides. Therefore, the prepared sulfur-mold spore carbon / metal carbide-plasma reduced graphene fiber non-woven composite material has excellent conductivity and flexibility, and as a self-supporting lithium-sulfur battery positive electrode material, it has high specific capacity and excellent cycle rate performance.

[0048] Therefore, the lithium-sulfur battery sulfur-mold spore carbon / metal carbide-plasma reduced graphene fiber non-woven composite material of the present application has excellent sulfur fixation and catalytic effect, high specific capacity, high cycle life and high rate performance, and the graphene non-woven material is light in weight and has good mechanical properties, which endows the electrode material with good flexibility, and has wide application prospects in the fields of wearable devices, medical implantable devices, electronic skin and smart electronic textiles.

Claims

1. A method for preparing a mold spore carbon / metal carbide-plasma reduced graphene oxide fiber self-supporting material, characterized in that: The following steps are involved: (1) The mold spores are subjected to high-temperature heat treatment in argon gas at a temperature of 600-1000°C, a heating time of 1-5 hours, and a heating rate of 1-10°C min -1 , after cooling, a mold spore carbon material is obtained; (2) soaking the mold spore carbon material obtained in step (1) in an ethanol solution containing a metal alcohol or ester solvent, transferring it to a reactor and treating it by a solvent thermal method at a treatment temperature of 100-300° C. for 10-24 hours, and filtering and drying it to obtain a mold spore carbon / metal oxide composite material; (3) subjecting the mold spore carbon / metal oxide composite material obtained in step (2) to high-temperature carbon heat treatment in argon at a heating temperature of 700-1500°C, a heating time of 1-5 hours, and a heating rate of 1-10°C min -1 , after cooling, a mold spore carbon / metal carbide composite material is obtained; (4) adding the mold spore carbon / metal carbide composite material obtained in step (3) to a graphene oxide solution to obtain a dispersion, and then wet spinning the dispersion, and obtaining a mold spore carbon / metal carbide-graphene oxide fiber self-supporting material after suction filtration and drying; (5) placing the mold spore carbon / metal carbide-graphene oxide fiber self-supporting material obtained in step (4) into a plasma discharge chamber, evacuating the chamber and introducing gas, generating a gas plasma flow in the discharge chamber by adjusting the gas flow rate and radio frequency power, and the gas plasma flow directly acts on the surface of the mold spore carbon / metal carbide-graphene oxide fiber self-supporting material, and obtaining the mold spore carbon / metal carbide-plasma reduced graphene oxide fiber self-supporting material after the reaction.

2. The preparation method according to claim 1, characterized in that In step (1), the mold spores are Aspergillus spores, Penicillium spores, Trichoderma spores, Mucor spores or Rhizopus spores.

3. The preparation method according to claim 1, characterized in that In step (2), the metal alcohol or ester solvent is one or more of metal nickel-containing alcohol solvents, metal nickel-containing alcohol ester solvents, metal cobalt-containing alcohol solvents, metal cobalt-containing alcohol ester solvents, metal iron-containing alcohol solvents, metal iron-containing ester solvents, metal manganese-containing alcohol solvents, metal manganese-containing ester solvents, metal titanium-containing alcohol solvents, and metal titanium-containing ester solvents.

4. The preparation method according to claim 1, characterized in that In step (3), the metal carbide is one or more of nickel carbide, cobalt carbide, iron carbide, manganese carbide and titanium carbide.

5. The preparation method according to claim 1, characterized in that In step (5), the gas introduced is one or more of hydrogen, argon, methane, and ammonia; In step (5), the flow rate of the introduced gas is 5-100 sccm.

6. The preparation method according to claim 1, characterized in that In step (5), the reaction conditions are: radio frequency power of 10-500W, vacuum degree of 5-30Pa, and reaction time of 1-30 minutes.

7. A mold spore carbon / metal carbide-plasma reduced graphene oxide fiber self-supporting material prepared according to the preparation method according to any one of claims 1 to 6.

8. A method for preparing sulfur-mold spore carbon / metal carbide-plasma reduced graphene oxide fiber material, characterized in that: include: The mold spore carbon / metal carbide-plasma reduced graphene oxide fiber self-supporting material prepared by the preparation method according to any one of claims 1 to 6 and nano-sulfur are placed in a quartz tube, sealed by vacuum, and steam sulfurized at high temperature to obtain a sulfur-mold spore carbon / metal carbide-plasma reduced graphene oxide fiber material; The high temperature treatment temperature is 400-500°C and the treatment time is 5-30 hours.

9. The preparation method according to claim 8, characterized in that The mass ratio of the mold spore carbon / metal carbide-plasma reduced graphene oxide fiber self-supporting material and nano-sulfur is 1:1-1:

10.

10. Use of the mold spore carbon / metal carbide-plasma reduced graphene oxide fiber self-supporting material according to claim 7 and the sulfur-mold spore carbon / metal carbide-plasma reduced graphene oxide fiber material prepared according to the preparation method of claim 8 or 9 as positive electrode materials for lithium-sulfur batteries.

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