Modified carbon-supported sulfur electrode material and preparation method and application of self-supporting sulfur electrode

Abstract

The invention relates to a sodium-sulfur battery technology, and aims to provide a preparation method and application of a modified carbon-supported sulfur electrode material and a self-supporting sulfur electrode. The preparation method comprises the following steps: carrying out spray drying on a mixed solution containing aniline hydrochloric acid, ammonium persulfate hydrochloric acid and nano calcium carbonate to obtain a precursor, and carrying out carbonization and acid leaching to obtain a hydrophilic carbon carrier with primary and secondary pore channels; a positive plate is prepared to assemble a soft package battery, and potassium intercalation is realized through multiple times of potassium deintercalation and intercalation cycle treatment; disassembling and cleaning to obtain a potassium-embedded carbon carrier, reacting with transition metal nitrate, and forming monatomic transition metal clusters between graphite layers to enlarge the graphite spacing; removing potassium nitrate to obtain a modified carbon carrier which is provided with three-stage mass transfer channels and in which transition metal is loaded, then grinding and mixing the modified carbon carrier with elemental sulfur, performing heating treatment, and cooling to obtain the modified carbon sulfur-loaded electrode material. According to the invention, transition metal single atomic clusters are formed on the walls of the micropores while the interlamellar spacing of the graphite is enlarged to form the micropores, so that the cycling stability of the sodium-sulfur battery is effectively improved.

Description

Technical Field

[0001] The present invention relates to a sodium-sulfur battery technology, and more specifically, to a preparation method and application of a modified carbon-supported sulfur electrode material and a self-supporting sulfur electrode. Background Art

[0002] Sodium-sulfur (Na-S) batteries, as a new type of chemical power source, have made significant progress since their introduction. Due to their compact size, large capacity, long lifespan, and high efficiency, Na-S batteries are widely used in energy storage applications such as wind power generation, peak shaving, and emergency power supply. Na-S batteries are divided into two categories: high-temperature Na-S batteries and room-temperature Na-S batteries. High-temperature Na-S batteries consist of a positive electrode, a negative electrode, an electrolyte, a separator, and a casing. Unlike conventional secondary batteries, high-temperature Na-S batteries utilize molten electrodes and a solid electrolyte. The active material in the negative electrode is molten sodium metal, while the active material in the positive electrode is liquid sulfur and molten sodium polysulfide salt.

[0003] High-temperature sodium-sulfur batteries have many unique features. Their theoretical specific energy is as high as 760Wh / Kg. They can discharge at high current and power, and the discharge current density can generally reach 200-300mA / cm 2 , with excellent high-rate charge and discharge performance and high charge and discharge efficiency. The use of solid electrolytes effectively suppresses side reactions such as self-discharge and the shuttle effect, resulting in a charge and discharge current efficiency of almost 100%. However, high-temperature sodium-sulfur batteries operate at temperatures between 300 and 350°C, requiring certain heating and insulation during operation. Furthermore, both liquid sodium and liquid sulfur are highly active substances, posing certain safety risks.

[0004] Although high-temperature sodium-sulfur batteries have been successfully used in large-scale energy storage for nearly 20 years, their high operating temperatures and the increased safety risks associated with high temperatures have long been a concern, making their application in room-temperature power batteries and portable batteries difficult. Consequently, a series of research efforts have been conducted in recent years to explore room-temperature sodium-sulfur batteries.

[0005] Unlike high-temperature sodium-sulfur batteries that use solid electrolytes, room-temperature sodium-sulfur batteries use ethers: a mixed solvent of dioxolane (DOL) and ethylene glycol dimethyl ether (DME) or an organic electrolyte of a mixed solvent system of esters: ethylene carbonate (EC) and diethyl carbonate (DEC). Since the electrolyte has a certain dissolving effect on sodium polysulfide, a shuttle effect occurs during the charge and discharge process, which seriously damages the performance and life of the sodium-sulfur battery. The so-called shuttle effect refers to the polysulfide (Na2S x ) intermediates dissolve into the electrolyte, pass through the diaphragm, diffuse to the negative electrode, and directly react with the metallic sodium at the negative electrode, ultimately causing irreversible loss of effective substances in the battery, attenuation of battery life, and low coulombic efficiency.

[0006] In order to suppress the shuttle effect, carbon supports with high specific surface area and porous structure (such as graphene, carbon nanotubes), metal organic frameworks (MOFs), and conductive polymers (such as polypyrrole) are used to physically adsorb and localize sulfur and polysulfides, or to chemically modify the carbon supports to form active sites and increase the polarity of the carbon materials to enhance the chemical adsorption of Na2S. x The ability of the sulfur electrode can inhibit the polysulfide shuttle effect to a certain extent, which helps to improve the cycle stability of the sulfur electrode.

[0007] Na2S x The shuttle effect mainly occurs in the early discharge process of the sulfur electrode. Due to the continuous formation of soluble polysulfides, Na2S in the electrolyte x The concentration of Na2S increases significantly, forming a concentration gradient that diffuses toward the sodium electrode. x The reaction forms insoluble Na2S on the sodium electrode, which reduces the sulfur utilization rate and thus causes the so-called shuttle effect. The late discharge is a process in which Na2S continuously forms nuclei and grows at the catalytic center. Although Na2S in the electrolyte x The concentration of Na2S is thus reduced, but the product Na2S will hinder the reduction of soluble polysulfides in the electrolyte at the catalytic center, causing the catalytic center to deactivate and capacity fade. Similarly, during the charging process, Na2S is continuously oxidized to form soluble polysulfides in the early stage, exacerbating the shuttle effect. In the later stage, the soluble polysulfides are further oxidized to form elemental sulfur (S8). The nucleation and growth of S8 at the catalytic center will also hinder the oxidation of soluble polysulfides in the electrolyte at the catalytic center, also causing capacity fade.

[0008] Therefore, Na2S is avoided during the charge and discharge process. x The shuttle effect and the influence of the growth of electrochemical reaction products on the mass transfer process have become key factors in improving the performance and life of sulfur electrodes. The present invention proposes a new solution to improve the sulfur electrode catalyst, not only to improve its ability to adsorb polysulfides, but also to fully improve the mass transfer conditions and avoid the influence of the growth of reaction products on the mass transfer process. Summary of the Invention

[0009] The present invention aims to overcome the shortcomings of the prior art by providing a modified carbon-supported sulfur electrode material and a method for preparing and applying a self-supporting sulfur electrode. This electrode material can inhibit polysulfide shuttling and overcome the Na2S barrier. After preparing the self-supporting sulfur electrode, it can be used in room-temperature sodium-sulfur batteries.

[0010] In order to solve the technical problem, the technical solution of the present invention is:

[0011] A method for preparing a modified carbon-supported sulfur electrode material is provided, comprising the following steps:

[0012] (1) mixing aniline hydrochloric acid solution and ammonium persulfate hydrochloric acid solution in an ice bath, stirring continuously, and then filtering under reduced pressure to obtain a paste of aqueous polyaniline; dispersing with deionized water, adding nano-calcium carbonate, stirring and mixing, and spray drying to obtain a precursor;

[0013] (2) The precursor is carbonized in a nitrogen atmosphere, soaked in dilute hydrochloric acid, filtered, washed, and dried to obtain a hydrophilic carbon support with primary and secondary pores; nano-calcium carbonate serves as a primary pore template, and polyaniline is released by gasification during carbonization to form secondary pores;

[0014] (3) The hydrophilic carbon carrier is made into a slurry and then coated on a copper foil, which is dried to obtain a positive electrode sheet; the positive electrode sheet, the separator, and the potassium metal sheet are assembled in this order and an electrolyte is added to obtain a soft-pack battery, which is subjected to several potassium intercalation and deintercalation cycles to finally achieve potassium intercalation; after disassembling the battery, the positive electrode sheet is taken out, and the coating layer on the copper foil is ultrasonically separated in a solvent, and the potassium intercalated carbon carrier is obtained after washing, filtering, and drying;

[0015] (4) dissolving a transition metal nitrate in acetonitrile, adding a potassium-embedded carbon support, and stirring the reaction to form single-atom transition metal clusters between graphite layers of the carbon support, thereby expanding the graphite spacing; then removing the potassium nitrate generated by the reaction to obtain a modified carbon support having a tertiary mass transfer channel and transition metal-loaded pores;

[0016] (5) Grinding and mixing the modified carbon support and elemental sulfur, heating them under a nitrogen atmosphere, and cooling them to obtain a modified carbon-supported sulfur electrode material.

[0017] As a preferred embodiment of the present invention, in step (1), aniline and ammonium persulfate are respectively dissolved in a hydrochloric acid solution to obtain an aniline hydrochloric acid solution and an ammonium persulfate hydrochloric acid solution, wherein the molar ratio of aniline to ammonium persulfate is 1:1; and the mass ratio of nano-calcium carbonate to aniline is 2 to 4:1.

[0018] As a preferred embodiment of the present invention, in step (2), the heating rate during the carbonization treatment is 10°C / min, the temperature is raised to 850°C and maintained for 2 hours, and then cooled to room temperature.

[0019] As a preferred embodiment of the present invention, the step (3) specifically comprises: using N-methylpyrrolidone (NMP) as a dispersant, mixing a hydrophilic carbon support and polyvinylidene fluoride (PVDF) in a mass ratio of 9:1, grinding the mixture into a slurry, and then uniformly coating the mixture on a copper foil; drying the mixture in a vacuum oven at 60°C for 12 hours to obtain a positive electrode sheet; the separator is a glass fiber separator; the electrolyte is a mixed solution formed by dissolving potassium perchlorate in propylene carbonate and ethylene carbonate, wherein the volume ratio of propylene carbonate to ethylene carbonate in the mixed solution is 1:1, and the concentration of potassium perchlorate (KClO4) is 1 mol L -1; Assemble the soft pack battery in an Ar atmosphere glove box, evacuate the vacuum and add the electrolyte; perform potassium intercalation and deintercalation cycles in the range of 0.001 to 1.5 V, with the number of cycles ranging from 2 to 10, and finally intercalate potassium to 0.001 V vs. K / K + ; The disassembled positive electrode sheet was placed in N-methylpyrrolidone solution for ultrasonic separation, and the potassium-embedded carbon support was cleaned with tetrahydrofuran (THF).

[0020] As a preferred embodiment of the present invention, the operation in step (4) is carried out in a glove box with an Ar atmosphere, the amount of transition metal nitrate and acetonitrile used is 1 to 2 g / 100 mL, and the stirring reaction time is 2 h; the modified carbon support is washed with deionized water to remove potassium nitrate generated by the reaction, and the modified carbon support is obtained by vacuum drying; the transition metal content in the modified carbon support is 0.3 to 3 wt%, and the transition metal is any one or more of the fourth period elements VIIB, VIII, IB and IIB.

[0021] As a preferred embodiment of the present invention, in step (5), the heating treatment temperature is 155° C. and the holding time is 2 h; and the sulfur content in the modified carbon-supported sulfur electrode material is 50 to 90 wt %.

[0022] The present invention further provides the use of the modified carbon-supported sulfur electrode material prepared by the aforementioned method in preparing a self-supporting sulfur electrode for a room-temperature sodium-sulfur battery.

[0023] The present invention also provides a method for further preparing a self-supporting sulfur electrode for a room-temperature sodium-sulfur battery using the modified carbon support and the modified carbon-supported sulfur electrode material prepared by the aforementioned method, comprising: dissolving aniline and ammonium persulfate in a hydrochloric acid solution, respectively, to obtain an aniline hydrochloric acid solution and an ammonium persulfate hydrochloric acid solution; adding the modified carbon support and the modified carbon-supported sulfur material to the aniline hydrochloric acid solution, and continuously stirring in an ice bath; then adding the ammonium persulfate hydrochloric acid solution to carry out an aniline polymerization reaction; and performing reduced pressure filtration and vacuum drying to obtain a self-supporting sulfur electrode.

[0024] As a preferred embodiment of the present invention, the molar ratio of aniline to ammonium persulfate is 1:1; the mass ratio of the modified carbon-supported sulfur electrode material, the modified carbon support and aniline is 6-9:2:1, and the sulfur loading of the self-supporting sulfur electrode is 0.5-2.0 mg / cm 2 .

[0025] The present invention also provides a method for further preparing a room-temperature sodium-sulfur battery using the self-supporting sulfur electrode prepared by the above method, comprising: in an argon atmosphere glove box, stacking the self-supporting sulfur electrode, a diaphragm, and a sodium metal sheet, and then placing the stacked stacked stacks into a battery shell, dripping an electrolyte, and then encapsulating the battery to obtain a room-temperature sodium-sulfur battery; the electrolyte uses a 1M concentration of NaTFSI / TEGDME, that is, 1 mol of Na[CF3SO2)2N](NaTFSI) is dissolved in 1 liter of tetraethylene glycol dimethyl ether (TEGDME), and the electrolyte contains 1.5wt% of NaNO3 as an additive; the diaphragm is a microporous polypropylene diaphragm.

[0026] Description of the invention principle:

[0027] 1. The present invention uses ammonium persulfate to initiate aniline polymerization to obtain conductive polymer polyaniline. Nano calcium carbonate is added to the polyaniline suspension dispersed in deionized water. The polyaniline molecular chain contains a large number of amino functional groups (-NH-) and imino functional groups (=N-). These groups can react with calcium ions (Ca 2+ ) or carbonate (CO3 2- ) forms coordination bonds or ion-dipole interactions, enhancing interfacial bonding and forming chemical bonds with the nano-calcium carbonate particle contact interface. This method forms a polyaniline coating on the surface of the nano-calcium carbonate particles, while simultaneously inhibiting the agglomeration of the nano-calcium carbonate and effectively dispersing the nano-calcium carbonate template, allowing a uniform precursor to be formed through spray drying.

[0028] 2. The present invention utilizes a precursor containing polyaniline and nano-calcium carbonate to form a primary channel based on the template nano-calcium carbonate during carbonization, and polyaniline is thermally decomposed to form a secondary channel. When the carbon support with primary and secondary channels is electrochemically embedded with K to obtain K-embedded porous carbon, it reacts with a transition metal nitrate acetonitrile solution to form a tertiary channel and realizes transition metal deposition in the tertiary channel to form a catalytic center. Acetonitrile has good wettability for nitrogen-doped porous carbon, and the transition metal acetonitrile solution can smoothly diffuse into any gap in the porous carbon to react with K to form a transition metal deposition, expanding the space between the graphite layers to accommodate the electrolyte. The increase in polarity and micropores of nitrogen-containing porous carbon effectively enhances the adsorption of sodium polysulfide in the electrolyte and suppresses its shuttle effect. The formation of tertiary electrolyte transmission channels effectively guides ion transmission channels and improves the apparent electrochemical reaction kinetics.

[0029] 3. The transition metal-supported porous carbon of the present invention has two types of catalytic centers. One type is pyridinic nitrogen (=N-), which is distributed on any surface of the porous carbon. The other type is transition metal, which is distributed in the tertiary pores. The catalytic activity of transition metals for the electrochemical reduction of sulfur and the electrochemical oxidation of sodium sulfide is higher than that of pyridinic nitrogen. Therefore, the charge and discharge of the sodium-sulfur battery occurs preferentially in the tertiary pores, generating S4 dissolved in the electrolyte. 2- and S72- ions. When the sodium-sulfur battery is discharged, the electrochemical reduction of S8 occurs preferentially on the highly active transition metal catalytic centers:

[0030] 1 / 2S8↓+2Na + +2e - →Na2S4 (1)

[0031] Generated S4 2- Can react with S8 to generate S6 2- ,

[0032] Na2S4+1 / 4S8↓→Na2S6 (2)

[0033] S8 dissolved on the pyridinic nitrogen, thereby promoting the electrochemical reduction of S8.

[0034] When sodium-sulfur batteries are charged, electrochemical oxidation of Na2S occurs preferentially on highly active transition metals:

[0035] 7Na2S↓ → Na2S7 + 12Na + + 12e - (3)

[0036] Generated S7 2- Can react with Na2S to generate S4 2- ,

[0037] Na2S7 + Na2S↓→ 2Na2S4 (4)

[0038] Na2S dissolved on the pyridinic nitrogen, thereby promoting the electrochemical oxidation of Na2S.

[0039] 4. The preferred transition metals of the fourth period elements VIIB, VIII, IB and IIB of the present invention are sulfide-philic elements that can form sulfides of various valence states with sulfur, such as manganese sulfides: MnS, Mn2S3, Mn3S4, MnS2, etc., iron sulfides: FeS, FeS2, Fe3S4, Fe2S3, etc., cobalt sulfides: CoS, Co3S4, CoS2, Co9S8, etc., nickel sulfides: NiS, Ni3S2, NiS2, Ni3S4, Ni7S6, etc., copper sulfides: Cu2S, CuS, Cu 2-x S (x = 0 ~ 0.25), NiS2, Ni3S4, Ni7S6, etc., and zinc sulfides: ZnS, Zn 1-xS (x = 0 ~ 0.25), etc., especially those with the ability to embed sodium, forming sodium thiotransition metal acids, such as: Na2MnS2, NaFeS2, NaCoS2, NaNiS2, NaCuS, Na2ZnS2. The presence of these sulfides and thio compounds creates conditions for the sodium removal dissolution of sodium sulfide and the sodium embedding dissolution of S8, which is beneficial to the electrochemical redox reaction of the sulfur electrode.

[0040] Taking manganese-supported porous carbon as an example, a modified porous carbon-supported sulfur material with metal manganese atomic clusters is obtained by sulfur loading. Mn reacts with sulfur to form MnS2. When the sodium-sulfur battery discharges, Na ions migrate from the anode to the cathode, and S8 is electrochemically reduced to form Na2S. As the discharge proceeds, part of the Na in Na2S is embedded in part of MnS2 to form Na2MnS2, forming a catalytic center of Na2MnS2 / MnS2 / C. In the subsequent charging process, the sulfur electrode de-sodiumizes, preferentially de-sodiumizing Na2MnS2 in Na2MnS2 / MnS2 / C. The content of Na2MnS2 decreases, while the content of MnS2 increases. Due to the concentration gradient difference, the Na in Na2S migrates to MnS2 and is converted into Na2S7, which dissolves in the electrolyte, thereby promoting the following reaction process:

[0041] 7Na2S↓→Na2S7+12Na + (Embedded MnS2) -

[0042] The S7 generated in this reaction 2- Can further react with Na2S to generate S4 2- , the reaction formula is as follows:

[0043] Na2S7+Na2S↓→2Na2S4

[0044] By dissolving Na2S on the catalytic center, the electrochemical oxidation of Na2S is promoted, and finally S8 is formed and deposited on MnS2 / C.

[0045] 5. The present invention forms a self-supporting sulfur electrode by in-situ polymerization of polyaniline. As a conductive polymer, polyaniline can significantly improve the electronic conductivity of the sulfur electrode. At the same time, the nitrogen atoms in the abundant imino functional groups (=N-) on polyaniline adopt sp 2 Hybridization, its lone pair of electrons occupy p orbital and participate in the conjugated system. This conjugation leads to the delocalization of nitrogen's outer electrons, reducing the electron density around the nitrogen atom, thus showing electron-deficient characteristics, strengthening the adsorption of soluble sodium polysulfide, further inhibiting the occurrence of the shuttle effect, and at the same time due to the adsorbed S x 2- It supplies power to the conjugated system of polyaniline, strengthens electron conduction, and further improves the conductivity of the sulfur electrode.

[0046] 6. The micropores between the transition metal-supported graphite layers formed by K intercalation and reduction of transition metal nitrates in the present invention effectively limit the crystal size of Na2S and S8, forming microcrystalline Na2S and S8, effectively improving the reactivity of Na2S and S8, thereby improving the cycle stability and rate charge and discharge performance of the sulfur electrode.

[0047] 7. In the process of forming the conductive bonding network based on polyaniline of the present invention, the imino groups (=N-) in polyaniline are protonated (=N + -H), becoming electron-deficient centers. The lone pair electrons of the sulfur atom (S8) can form Lewis acid-base interactions or charge transfer complexes with these electron-deficient nitrogen sites, thereby enhancing chemical adsorption. Moreover, the porous structure and chain morphology of polyaniline can effectively cover the surface of sulfur particles, limit the volume expansion of sulfur, and prevent the dissolution of polysulfides to form a physical coating effect, thereby improving the utilization rate of sulfur. In the acidic doping state, polyaniline carries a positive charge (such as -NH + =), and polysulfide (Na2S x ,4≤x≤8) are negatively charged in the electrolyte, which further suppresses the shuttle effect through electrostatic interaction and improves the cycle stability of the sulfur electrode.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] 1. The present invention embeds potassium into the cathode catalyst carbon support and reacts with transition metal nitrates. While expanding the distance between its graphite layers to form micropores, transition metal single-atom clusters are formed on the micropore walls, effectively promoting the nucleation of sulfur and sodium sulfide during the electrochemical reaction, and can effectively improve the cycle stability of sodium-sulfur batteries.

[0050] 2. This invention proposes a nitrogen-containing, sulfur-loaded carbon material with a tertiary pore structure, which facilitates the adsorption of polysulfides. In particular, the presence of nanometer-sized tertiary pores favors the formation of microcrystalline Na2S and S8, enhancing their reactivity and reducing cathode impedance. By constructing catalytic centers of varying activity within the tertiary pores, this invention achieves controlled coupling of electrochemical and chemical reactions, enabling controlled dissolution and deposition of active sulfur electrode material, preventing the formation of inert Na2S, and thereby improving active material utilization and cyclic performance stability.

[0051] 3. This invention overcomes the shortcomings of traditional high-temperature sodium-sulfur batteries by achieving electrochemical reactions at room temperature, improving their safety, reducing costs, and facilitating operation. It can be applied to power supplies and mobile power sources.

[0052] 4. Compared to the supported sulfur electrodes used in conventional room-temperature sodium-sulfur batteries, the self-supporting sulfur electrode in this invention, which uses polyaniline as a binder, enhances the adsorption of soluble polysulfides, inhibits the shuttle effect, and simultaneously improves the electronic conductivity of the sulfur electrode, reducing cathode impedance. The integrated rigid polyaniline bonding network effectively disperses the stress generated during charge and discharge in the sulfur electrode, thereby extending the electrode's cycle life.

[0053] 5. Compared with the traditional room-temperature sodium-sulfur battery that uses solid carbon materials such as acetylene black as a conductive agent, the present invention uses nitrogen-containing porous carbon as a conductive agent, which not only improves the electrolyte absorption capacity of the sulfur electrode, but also enhances the adsorption of soluble polysulfides, inhibits the shuttle effect, and at the same time improves the ion conductivity of the sulfur electrode, reduces the cathode impedance, and is also conducive to the in-situ polymerization of polyaniline to form a self-supporting electrode, thereby improving the electrode cycle life.

[0054] 6. The aniline used in the present invention has a good affinity with S8. During in-situ polymerization of polyaniline, polyaniline can polymerize on the surface of S8 crystals. Therefore, polyaniline can extend to the tertiary pores through the primary and secondary pores, effectively covering the surface of S8 crystals, improving the polysulfide adsorption efficiency, inhibiting the escape of polysulfide from the pores, effectively inhibiting the shuttle effect, and improving the cycle life of the electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a scanning electron microscope photograph of the nitrogen-containing porous carbon material prepared in Example 2.

[0056] Figure 2 This is a high-resolution transmission electron microscope photograph of the manganese-embedded porous carbon material prepared in Example 4.

[0057] Figure 3 The sulfur-carrying material of the cobalt-embedded porous carbon prepared in Example 6 and the elemental sulfur S 2p XPS comparison results.

[0058] Figure 4 This is the CV curve of the sulfur electrode based on the zinc-embedded modified porous carbon sulfur-supported material prepared in Example 9.

[0059] Figure 5 This is the cycle life of the sodium-sulfur battery based on the zinc-embedded modified porous carbon-supported sulfur material prepared in Example 10.

[0060] The reference numerals in the figures are:

[0061] 3-1 S of elemental sulfur 2p XPS spectrum of 3-2 cobalt-embedded porous carbon-supported sulfur material 2p XPS spectrum.

[0062] 4-1 Cathode process of sulfur electrode: sodium reaction process; 4-2 Anode process of sulfur electrode: desodium reaction process.

[0063] 5-1 Cycling behavior of sodium-sulfur batteries based on traditional porous carbon-sulfur electrodes; 5-2 Cycling behavior of sodium-sulfur batteries based on modified sulfur electrodes based on zinc-embedded modified porous carbon. DETAILED DESCRIPTION

[0064] The present invention is further described in detail below in conjunction with specific embodiments:

[0065] Example 1: Preparation of porous carbon material precursor

[0066] Dissolve 20 mmol of aniline and 20 mmol of ammonium persulfate in 100 mL of 1 mol / L hydrochloric acid solution, respectively, to obtain an aniline hydrochloric acid solution and an ammonium persulfate hydrochloric acid solution. Add the ammonium persulfate hydrochloric acid solution to the aniline hydrochloric acid solution in an ice bath. Stir the mixed solution for 5 hours, then filter under reduced pressure to obtain a paste of aqueous polyaniline. Disperse the polyaniline in deionized water, add 3.72 g of nano-calcium carbonate (nano-calcium carbonate:aniline mass ratio of 2:1), stir, and spray-dry to obtain a precursor.

[0067] Example 2: Preparation of nitrogen-containing porous carbon material

[0068] Dissolve 35 mmol of aniline and 35 mmol of ammonium persulfate in 100 mL of 1 mol / L hydrochloric acid solution to obtain an aniline hydrochloric acid solution and an ammonium persulfate hydrochloric acid solution, respectively. Add the ammonium persulfate hydrochloric acid solution to the aniline hydrochloric acid solution in an ice bath. Stir the mixed solution for 5 hours and then filter under reduced pressure to obtain a paste of aqueous polyaniline. Disperse the polyaniline in deionized water, add 9.78 g of nano-calcium carbonate (nano-calcium carbonate:aniline mass ratio:3:1), stir, and spray-dry to obtain a precursor.

[0069] The precursor was placed in a nitrogen atmosphere and heated to 850°C at a rate of 10°C / min. After being kept constant for 2 hours, it was cooled to room temperature to complete carbonization. The carbonized material was soaked in dilute hydrochloric acid (5wt%) to remove the nano-calcium carbonate template and salt components, and then filtered, washed, and dried to obtain a hydrophilic carbon support with primary and secondary pores. Figure 1 A scanning electron microscope photo of it.

[0070] Example 3: Preparation of potassium-embedded porous carbon material

[0071] Dissolve 50 mmol of aniline and 50 mmol of ammonium persulfate in 100 mL of 1 mol / L hydrochloric acid solution to obtain an aniline hydrochloric acid solution and an ammonium persulfate hydrochloric acid solution, respectively. Add the ammonium persulfate hydrochloric acid solution to the aniline hydrochloric acid solution in an ice bath. Stir the mixed solution for 5 hours and then filter under reduced pressure to obtain a paste of aqueous polyaniline. Disperse the polyaniline in deionized water, add 18.63 g of nano-calcium carbonate (nano-calcium carbonate:aniline mass ratio:4:1), stir, and spray-dry to obtain a precursor.

[0072] The precursor was placed in a nitrogen atmosphere and heated to 850°C at a rate of 10°C / min. After being held at this temperature for 2 hours, it was cooled to room temperature to complete carbonization. The carbonized material was soaked in dilute hydrochloric acid (5wt%) to remove the nano-calcium carbonate template and salt components. It was then filtered, washed, and dried to obtain a hydrophilic carbon support with primary and secondary pores.

[0073] Using N-methylpyrrolidone (NMP) as a dispersant, the above-mentioned carbon support and polyvinylidene fluoride (PVDF) were mixed and ground into a slurry in a mass ratio of 9:1, evenly coated on a copper foil, and dried in a vacuum oven at 60°C for 12 hours to obtain a positive electrode sheet. After assembling the soft-pack battery in an Ar atmosphere glove box in the order of positive electrode sheet, separator, and metal potassium sheet, the electrolyte was added dropwise under vacuum, and potassium was inserted to 0.001V vs. K / K after two cycles of potassium insertion and removal in the range of 0.001-1.5V at a current density of 50mA / g. + The battery was disassembled in a glove box, the positive electrode was placed in NMP solution, and the copper foil and potassium-intercalated carbon support were ultrasonically separated. The potassium-intercalated carbon support was obtained by washing with THF, filtering, and drying. The electrolyte contained 1 mol / L potassium perchlorate (KClO4). -1 The membrane was a mixed solution of propylene carbonate (PC) and ethylene carbonate (EC) (volume ratio 1:1), and the separator was a commercially available glass fiber membrane (Whatman GF / D).

[0074] Example 4: Preparation of porous carbon material with graphite layers embedded in metal manganese clusters

[0075] Using N-methylpyrrolidone (NMP) as a dispersant, the porous carbon obtained in Example 2 and polyvinylidene fluoride (PVDF) were mixed and ground into a slurry in a mass ratio of 9:1, evenly coated on a copper foil, and dried in a vacuum oven at 60°C for 12 hours to obtain a positive electrode sheet. After assembling the soft-pack battery in an Ar atmosphere glove box in the order of positive electrode sheet, separator, and metal potassium sheet, the electrolyte was added dropwise under vacuum, and after 5 cycles of potassium insertion and removal in the range of 0.001 to 1.5V at a current density of 50mA / g, potassium was inserted to 0.001V vs.K / K. + The battery was disassembled in a glove box, the positive electrode was placed in NMP solution, and the copper foil and potassium-intercalated carbon support were ultrasonically separated. The potassium-intercalated carbon support was obtained by washing with THF, filtering, and drying. The electrolyte contained 1 mol / L potassium perchlorate (KClO4). -1 The membrane was a mixed solution of propylene carbonate (PC) and ethylene carbonate (EC) (volume ratio 1:1), and the separator was a commercially available glass fiber membrane (Whatman GF / D).

[0076] In an Ar atmosphere glove box, 1 g of anhydrous manganese nitrate was dissolved in 100 mL of acetonitrile. 10 g of the potassium-embedded carbon support was added to the manganese nitrate acetonitrile solution and stirred for 2 h. Manganese single atom clusters (Mn content 3 wt%) were formed between the graphite layers of the carbon support, which expanded the graphite spacing. The potassium nitrate was removed with deionized water and then vacuum dried to obtain a modified carbon support with a three-level mass transfer channel and metal manganese atomic clusters in the pores. Its high-resolution transmission electron microscopy showed that Figure 2 shown.

[0077] Example 5: Preparation of porous carbon material with graphite layers embedded in metallic iron clusters

[0078] Using N-methylpyrrolidone (NMP) as a dispersant, the porous carbon obtained in Example 2 and polyvinylidene fluoride (PVDF) were mixed and ground into a slurry in a mass ratio of 9:1, evenly coated on a copper foil, and dried in a vacuum oven at 60°C for 12 hours to obtain a positive electrode sheet. After assembling the soft-pack battery in an Ar atmosphere glove box in the order of positive electrode sheet, separator, and metal potassium sheet, the electrolyte was added dropwise under vacuum, and after 10 potassium-deintercalation cycles in the range of 0.001 to 1.5 V at a current density of 50 mA / g, potassium was intercalated to 0.001 V vs. K / K. + The battery was disassembled in a glove box, the positive electrode was placed in NMP solution, and the copper foil and potassium-embedded carbon support were ultrasonically separated. The potassium-embedded carbon support was obtained by washing with THF, filtering, and drying. The electrolyte contained 1 mol / L potassium perchlorate (KClO4). -1 The membrane was a mixed solution of propylene carbonate (PC) and ethylene carbonate (EC) (volume ratio 1:1), and the separator was a commercially available glass fiber membrane (Whatman GF / D).

[0079] In an Ar atmosphere glove box, 1.5 g of anhydrous ferric nitrate was dissolved in 100 mL of acetonitrile, and then 20 g of the above-mentioned potassium-embedded carbon support was added to the ferric nitrate acetonitrile solution, and the reaction was stirred for 2 hours. Iron single atom clusters (Fe content 1.7 wt%) were formed between the graphite layers of the carbon support, which expanded the graphite spacing; the potassium nitrate was removed with deionized water and then vacuum dried to obtain a modified carbon support with a three-level mass transfer channel and metallic iron atom clusters in the pores.

[0080] Example 6: Preparation of Sulfur-Carrying Material Based on Porous Carbon with Graphite Layers Embedded in Metal Cobalt Clusters

[0081] In an Ar atmosphere glove box, 2 g of anhydrous cobalt nitrate was dissolved in 100 mL of acetonitrile, and 200 g of the potassium-embedded porous carbon material obtained in Example 3 was added to the cobalt nitrate acetonitrile solution, and the reaction was stirred for 2 h. Cobalt single atom clusters (Co content 0.3 wt%) were formed between the graphite layers of the carbon support, which expanded the graphite spacing. The potassium nitrate was removed with deionized water and then vacuum dried to obtain a modified carbon support with a three-level mass transfer channel and metal cobalt atomic clusters in the pores.

[0082] 5 g of the modified carbon carrier was ground and mixed with 5 g of elemental sulfur, and then heated to 155° C. under a nitrogen atmosphere, kept warm for 2 h, and cooled to obtain a modified carbon-supported sulfur material with a sulfur content of 50 wt%. Figure 3 As shown in the XPS study, compared with the S 2p Binding energy, S of modified carbon-supported sulfur materials 2p The double peak shifts toward the low binding energy direction, indicating that some S has obtained electrons from Co, forming a Co-S bond, thereby reducing the S 2p The binding energy of electrons demonstrates the formation of Co sulfide.

[0083] Example 7: Preparation of a self-supporting sulfur electrode based on a sulfur-supporting material supported on nickel-modified porous carbon

[0084] In an Ar atmosphere glove box, 1 g of anhydrous nickel nitrate was dissolved in 100 mL of acetonitrile, 20 g of the potassium-embedded porous carbon material obtained in Example 3 was added to the nickel nitrate acetonitrile solution, and the reaction was stirred for 2 h. Nickel single atom clusters (Ni content 1.6 wt%) were formed between the graphite layers of the carbon support, which expanded the graphite spacing. The potassium nitrate was removed with deionized water and then vacuum dried to obtain a modified carbon support with a three-level mass transfer channel and metal nickel atom clusters in the pores.

[0085] 4 g of the modified carbon support and 6 g of elemental sulfur were ground and mixed, and then heated to 155° C. under a nitrogen atmosphere, kept warm for 2 h, and cooled to obtain a modified carbon-supported sulfur material with a sulfur content of 60 wt%.

[0086] 20 mmol of aniline and 20 mmol of ammonium persulfate were dissolved in 100 mL of 1 mol / L hydrochloric acid solution to obtain aniline hydrochloric acid solution and ammonium persulfate hydrochloric acid solution, respectively. 3.6 g of the modified carbon support loaded with nickel atomic clusters and 10.8 g of the modified carbon-supported sulfur material were added to the aniline hydrochloric acid solution. After continuous stirring in an ice bath for 2 h, the ammonium persulfate hydrochloric acid solution was added to polymerize aniline for 5 h. The mixture was filtered under reduced pressure through commercially available hydrophilic carbon paper and dried in vacuo at 80°C for 12 h to obtain a self-supporting sulfur electrode. The molar ratio of aniline to ammonium persulfate was 1:1. The mass ratio of the modified carbon-supported sulfur electrode material, the modified carbon support, and aniline was 6:2:1. The sulfur loading of the sulfur electrode was 0.5 mg / cm 2 .

[0087] Example 8: Preparation of a self-supporting sulfur electrode based on a sulfur-supporting material supported on copper-modified porous carbon

[0088] In an Ar atmosphere glove box, 1 g of anhydrous copper nitrate was dissolved in 100 mL of acetonitrile, 20 g of the potassium-embedded porous carbon material obtained in Example 3 was added to the copper nitrate acetonitrile solution, and the reaction was stirred for 2 h. Copper single atom clusters (Cu content 1.7 wt%) were formed between the graphite layers of the carbon support, which expanded the graphite spacing. The potassium nitrate was removed with deionized water and then vacuum dried to obtain a modified carbon support with a three-level mass transfer channel and metallic copper atom clusters in the pores.

[0089] 3 g of the modified carbon support and 7 g of elemental sulfur were ground and mixed, and then heated to 155° C. under a nitrogen atmosphere, kept warm for 2 h, and cooled to obtain a modified carbon-supported sulfur material with a sulfur content of 70 wt%.

[0090] 35 mmol of aniline and 35 mmol of ammonium persulfate were dissolved in 100 mL of 1 mol / L hydrochloric acid solution to obtain aniline hydrochloric acid solution and ammonium persulfate hydrochloric acid solution, respectively. 6.4 g of the modified carbon support loaded with metallic copper atomic clusters and 22.4 g of the modified carbon-supported sulfur material were added to the aniline hydrochloric acid solution. After continuous stirring in an ice bath for 2 h, the ammonium persulfate hydrochloric acid solution was added to carry out aniline polymerization for 5 h. The mixture was filtered under reduced pressure through commercially available hydrophilic carbon paper and dried in vacuo at 80°C for 12 h to obtain a self-supporting sulfur electrode. The molar ratio of aniline to ammonium persulfate was 1:1. The mass ratio of the modified carbon-supported sulfur electrode material, the modified carbon support, and aniline was 7:2:1. The sulfur loading of the sulfur electrode was 1.0 mg / cm 2 .

[0091] Example 9: Preparation of sodium-sulfur battery based on sulfur-carrying material supported on zinc-modified porous carbon

[0092] In an Ar atmosphere glove box, 1 g of anhydrous zinc nitrate was dissolved in 100 mL of acetonitrile, and 20 g of the potassium-embedded porous carbon material obtained in Example 3 was added to the zinc nitrate acetonitrile solution, and the reaction was stirred for 2 h. Zinc single atom clusters (Zn content 1.7 wt%) were formed between the graphite layers of the carbon support, which expanded the graphite spacing. The potassium nitrate was removed with deionized water and then vacuum dried to obtain a modified carbon support with a three-level mass transfer channel and metal zinc atom clusters in the pores.

[0093] 2 g of the modified carbon support and 8 g of elemental sulfur were ground and mixed, and then heated to 155° C. under a nitrogen atmosphere, kept warm for 2 h, and cooled to obtain a modified carbon-supported sulfur material with a sulfur content of 80 wt%.

[0094] 35 mmol of aniline and 35 mmol of ammonium persulfate were dissolved in 100 mL of 1 mol / L hydrochloric acid solution to obtain aniline hydrochloric acid solution and ammonium persulfate hydrochloric acid solution, respectively. 6.4 g of the modified carbon support loaded with metal zinc atomic clusters and 25.6 g of the modified carbon-supported sulfur material were added to the aniline hydrochloric acid solution. After continuous stirring in an ice bath for 2 h, the ammonium persulfate hydrochloric acid solution was added to polymerize aniline for 5 h. The mixture was filtered under reduced pressure through commercially available hydrophilic carbon paper and dried in vacuo at 80°C for 12 h to obtain a self-supporting sulfur electrode. The molar ratio of aniline to ammonium persulfate was 1:1. The mass ratio of the modified carbon-supported sulfur electrode material, the modified carbon support, and aniline was 8:2:1. The sulfur loading of the sulfur electrode was 1.5 mg / cm 2 .

[0095] In an argon-filled glove box, the self-supporting sulfur electrode, separator, and sodium metal sheet were stacked and placed in a battery case. After electrolyte was added dropwise, the battery was packaged to produce a room-temperature sodium-sulfur battery. The electrolyte used was 1M NaTFSI / TEGDME, consisting of 1 mol of Na[CF3SO2)2N] (NaTFSI) dissolved in 1 liter of tetraethylene glycol dimethyl ether (TEGDME). The electrolyte contained 1.5 wt% NaNO3 as an electrolyte additive. The separator was a microporous polypropylene membrane (Celguard 2400) manufactured by Celgard. Figure 4 At a scanning rate of 0.1 mV / min, the CV curve of the self-supporting sulfur electrode of the present invention shows clear peaks of Na2S4 (2.28 V) and Na2S (1.7 V) during the reduction process of S8 (4-1), while the reduction current between 1.5 and 1.2 V corresponds to the reduction current of Zn 1- x During the oxidation process of Na2S (4-2), the two small oxidation peaks between 1.7 and 2.0 V correspond to Na2S and Zn intercalation. 1-x The oxidation current is formed by the deintercalation of S into sodium, and the broad oxidation peak at 2.38 V corresponds to the oxidation current of S8 formed by the electrochemical oxidation of Na2S4, Na2S6 and Na2S8.

[0096] Example 10: Cycle life of sodium-sulfur batteries based on sulfur-carrying materials supported on zinc-modified porous carbon

[0097] In an Ar atmosphere glove box, 1 g of anhydrous zinc nitrate was dissolved in 100 mL of acetonitrile, and 20 g of the potassium-embedded porous carbon material obtained in Example 3 was added to the zinc nitrate acetonitrile solution, and the reaction was stirred for 2 h. Zinc single atom clusters (Zn content 1.7 wt%) were formed between the graphite layers of the carbon support, which expanded the graphite spacing. The potassium nitrate was removed with deionized water and then vacuum dried to obtain a modified carbon support with a three-level mass transfer channel and metal zinc atom clusters in the pores.

[0098] 1 g of the modified carbon support was ground and mixed with 9 g of elemental sulfur, and then heated to 155° C. under a nitrogen atmosphere, kept warm for 2 h, and cooled to obtain a modified carbon-supported sulfur material with a sulfur content of 90 wt%.

[0099] 50 mmol of aniline and 50 mmol of ammonium persulfate were dissolved in 100 mL of 1 mol / L hydrochloric acid solution to obtain aniline hydrochloric acid solution and ammonium persulfate hydrochloric acid solution, respectively. 9.2 g of the modified carbon support loaded with metal zinc atomic clusters and 41.4 g of the modified carbon-supported sulfur material were added to the aniline hydrochloric acid solution. After continuous stirring in an ice bath for 2 h, the ammonium persulfate hydrochloric acid solution was added to polymerize aniline for 5 h. The mixture was filtered under reduced pressure through commercially available hydrophilic carbon paper to obtain a self-supporting sulfur electrode. The molar ratio of aniline to ammonium persulfate was 1:1. The mass ratio of the modified carbon-supported sulfur electrode material, the modified carbon support, and aniline was 9:2:1. The sulfur loading of the sulfur electrode was 2.0 mg / cm 2 .

[0100] For comparison, the hydrophilic carbon support with primary and secondary pores obtained in Example 2 was directly loaded with sulfur. After grinding and mixing 1g of the carbon support with 9g of elemental sulfur, it was heated to 155°C under a nitrogen atmosphere, kept warm for 2h, and cooled to obtain a comparative carbon-supported sulfur material with a sulfur content of 90wt%. The mass ratio of the comparative carbon-supported sulfur material, acetylene black and PVDF was 9:2:1, NMP was added for dispersion, coated on aluminum foil, and vacuum dried at 80°C for 12h to obtain a comparative traditional sulfur electrode. The sulfur loading of the sulfur electrode was 2.0mg / cm 2 .

[0101] In an argon-filled glove box, the self-supporting sulfur electrode, separator, and sodium metal sheet were stacked and placed in a battery case. After electrolyte was added dropwise, the battery was packaged to produce a room-temperature sodium-sulfur battery. The electrolyte used was 1M NaTFSI / TEGDME, consisting of 1 mol of Na[CF3SO2)2N] (NaTFSI) dissolved in 1 liter of tetraethylene glycol dimethyl ether (TEGDME). The electrolyte contained 1.5 wt% NaNO3 as an electrolyte additive. The separator was a microporous polypropylene membrane (Celguard 2400) manufactured by Celgard. Figure 5 Under 0.1C charge and discharge conditions, the self-supporting sulfur electrode of the present invention significantly outperforms conventional sulfur electrodes in terms of discharge specific capacity and cycle life. Conventional sulfur electrodes use macroporous carbon with primary and secondary pores as the sulfur-carrying material, PVDF as a binder, and acetylene black as a conductive agent. Charge and discharge cycle tests fully demonstrate that the self-supporting sulfur electrode of the present invention significantly suppresses the shuttling of sodium polysulfide and the expansion and damage of the sulfur electrode, while exhibiting a high specific capacity and a long cycle life.

[0102] Finally, the above disclosure is only a specific embodiment of the present invention. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered to be within the scope of protection of the present invention.

Claims

1. A method for preparing a modified carbon-supported sulfur electrode material, characterized in that: The following steps are involved: (1) mixing an aniline hydrochloric acid solution and an ammonium persulfate hydrochloric acid solution under ice bath conditions, continuously stirring, and then filtering under reduced pressure to obtain a paste of aqueous polyaniline; After dispersing with deionized water, nano calcium carbonate is added, stirred and mixed, and spray dried to obtain a precursor; (2) carbonizing the precursor in a nitrogen atmosphere, soaking it in dilute hydrochloric acid, filtering, washing, and drying it to obtain a hydrophilic carbon support with primary and secondary pores; Nano-calcium carbonate is the template for the primary pores, and polyaniline is released by gasification during carbonization to form the secondary pores. (3) The hydrophilic carbon carrier is made into a slurry and then coated on a copper foil, which is dried to obtain a positive electrode sheet; the positive electrode sheet, the separator, and the potassium metal sheet are assembled in this order and an electrolyte is added to obtain a soft-pack battery, which is subjected to several potassium intercalation and deintercalation cycles to finally achieve potassium intercalation; after disassembling the battery, the positive electrode sheet is taken out, and the coating layer on the copper foil is ultrasonically separated in a solvent, and the potassium intercalated carbon carrier is obtained after washing, filtering, and drying; (4) dissolving a transition metal nitrate in acetonitrile, adding a potassium-embedded carbon support, and stirring the reaction to form single-atom transition metal clusters between graphite layers of the carbon support, thereby expanding the graphite spacing; then removing the potassium nitrate generated by the reaction to obtain a modified carbon support having a tertiary mass transfer channel and transition metal-loaded pores; (5) Grinding and mixing the modified carbon support and elemental sulfur, heating them under a nitrogen atmosphere, and cooling them to obtain a modified carbon-supported sulfur electrode material.

2. The method according to claim 1, characterized in that In the step (1), aniline and ammonium persulfate are dissolved in hydrochloric acid solution to obtain aniline hydrochloric acid solution and ammonium persulfate hydrochloric acid solution respectively, wherein the molar ratio of aniline to ammonium persulfate is 1:1; and the mass ratio of nano-calcium carbonate to aniline is 2-4:

1.

3. The method according to claim 1, characterized in that In the step (2), the temperature is increased at a rate of 10°C / min during the carbonization treatment, and the temperature is increased to 850°C and maintained for 2 hours, and then cooled to room temperature.

4. The method according to claim 1, wherein The step (3) specifically comprises: using N-methylpyrrolidone as a dispersant, mixing a hydrophilic carbon carrier and polyvinylidene fluoride in a mass ratio of 9:1 to grind into a slurry, and then uniformly coating the mixture on a copper foil; drying in a vacuum oven at 60° C. for 12 hours to obtain a positive electrode sheet; the separator is a glass fiber separator; the electrolyte is a mixed solution formed by dissolving potassium perchlorate in propylene carbonate and ethylene carbonate, wherein the volume ratio of propylene carbonate to ethylene carbonate in the mixed solution is 1:1, and the concentration of potassium perchlorate is 1 mol / L -1 ; Assemble the soft pack battery in an Ar atmosphere glove box, evacuate the vacuum and add the electrolyte; perform potassium intercalation and deintercalation cycles in the range of 0.001 to 1.5 V, with the number of cycles ranging from 2 to 10, and finally intercalate potassium to 0.001 V vs. K / K + ; The disassembled positive electrode sheet was placed in N-methylpyrrolidone solution for ultrasonic separation treatment, and the potassium-embedded carbon support was cleaned with tetrahydrofuran.

5. The method according to claim 1, characterized in that The operation in step (4) is carried out in a glove box with an Ar atmosphere, the amount of transition metal nitrate and acetonitrile used is 1-2 g / 100 mL, and the stirring reaction time is 2 h; the modified carbon support is washed with deionized water to remove potassium nitrate generated by the reaction, and the modified carbon support is obtained by vacuum drying; the transition metal content in the modified carbon support is 0.3-3 wt%, and the transition metal is any one or more of the fourth period elements VIIB, VIII, IB and IIB.

6. The method according to claim 1, characterized in that In the step (5), the heating treatment temperature is 155° C. and the holding time is 2 hours; and the sulfur content in the modified carbon-supported sulfur electrode material is 50 to 90 wt%.

7. Use of the modified carbon-supported sulfur electrode material prepared by the method according to any one of claims 1 to 6 in preparing a self-supporting sulfur electrode for a room-temperature sodium-sulfur battery.

8. A method for further preparing a self-supporting sulfur electrode for a room-temperature sodium-sulfur battery using the modified carbon support and the modified carbon-supported sulfur electrode material prepared by the method according to any one of claims 1 to 6, characterized in that: include: Dissolving aniline and ammonium persulfate in a hydrochloric acid solution to obtain an aniline hydrochloric acid solution and an ammonium persulfate hydrochloric acid solution; The modified carbon support and the modified carbon-supported sulfur material were added to the aniline hydrochloric acid solution and stirred continuously in an ice bath; Then, ammonium persulfate hydrochloric acid solution is added to carry out aniline polymerization reaction; After reduced pressure filtration and vacuum drying, a self-supporting sulfur electrode was obtained.

9. The method according to claim 8, characterized in that The molar ratio of aniline to ammonium persulfate is 1:1; the mass ratio of the modified carbon-supported sulfur electrode material, the modified carbon support and aniline is 6-9:2:1, and the sulfur loading of the self-supporting sulfur electrode is 0.5-2.0 mg / cm 2 .

10. A method for further preparing a room-temperature sodium-sulfur battery using the self-supporting sulfur electrode prepared by the method of claim 8, characterized in that: include: In an argon atmosphere glove box, a self-supporting sulfur electrode, a diaphragm, and a sodium metal sheet were stacked and placed in a battery shell. After the electrolyte was added dropwise, it was packaged to obtain a room-temperature sodium-sulfur battery. The electrolyte used a 1M concentration of NaTFSI / TEGDME, that is, 1 mol of Na[CF3SO2)2N] was dissolved in 1 liter of tetraethylene glycol dimethyl ether, and the electrolyte contained 1.5wt% of NaNO3 as an additive. The diaphragm was a microporous polypropylene diaphragm.

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