A honeycomb carbon / bimetallic sulfide material, and methods of making and using the same

Abstract

The application belongs to the technical field of flame retardation, and particularly discloses a honeycomb carbon / bimetallic sulfide material, a preparation method and application thereof. The negative electrode made of the multifunctional material Fe-Sn-S@HC has better cycle and rate performance than the graphite negative electrode. The peak temperature of the battery using the Fe-Sn-S@HC negative electrode is obviously lower than that of the battery using the graphite negative electrode when thermal runaway occurs, which indicates that the thermal runaway risk of the battery is effectively inhibited. In addition, the electrochemical and safety performance of the LSBs can be significantly improved by using the commercial separator Fe-Sn-S@HC@C modified by the Fe-Sn-S@HC, and the thermal runaway hazard of the battery is reduced.

Description

Technical Field

[0001] This invention belongs to the field of flame retardant technology, and specifically discloses a honeycomb carbon / bimetallic sulfide material, its preparation method and application. Background Technology

[0002] The booming market for portable electronics and electric vehicles has attracted increasing attention. Lithium-ion batteries (LIBs) have been widely used in the energy storage industry due to their advantages such as small size, light weight, and absence of memory effect. Currently, graphite is the commonly used anode material for LIBs, with a theoretical specific capacity of only 372 mAh g. -1 Meanwhile, the scarcity of lithium resources severely limits the widespread application of LIBs. It is worth noting that, due to Na... + Due to its large ionic radius, graphite is not suitable for sodium-ion batteries (SIBs). See the following references: [Jian Xie et al, Self-assembly of CoS2 / graphenenanoarchitecture by a facile one-pot route and its improved electrochemical Li-storage properties.[J]. Nano Energy, 2013, 2: 49-56; Yujie. Zhu et al, Electrospun FeS2@Carbon Fiber Electrode as a High Energy Density Cathode for Rechargeable Lithium Batteries.[J]. ACS Nano, 2015, 10: 1529-1538; Qi Chen et al, Yolk-Shell NiS2 Nanoparticle-Embedded Carbon Fibers for Flexible Fiber-Shaped Sodium Battery.[J]. Advanced Energy...] [Materials, 2018, 8: 1800054.] It is known that in recent years, various transition metal sulfides such as CoS2, FeS2, and NiS2 have been used as anode materials for batteries. However, transition metal sulfides are prone to pulverization during ion insertion / deintercalation cycles, leading to severe capacity decay. Furthermore, transition metal sulfides exhibit significant volume changes during discharge / charge, easily causing anode material detachment and resulting in poor cycle stability.

[0003] To address the limitations of metal sulfides as battery anode materials, various composite anode materials combining sulfides and carbon have been developed in recent years. For example, see the literature [Jingjing Wang et al. An advanced MoS2 / carbonanode for high-performance sodium-ion batteries.[J].Small,2015,11(4):473-81.]. Wang et al. mixed MoS2 material with glucose and carried out a hydrothermal reaction to achieve carbon coating, followed by calcination to obtain the MoS2 / C composite material. However, the carbon-coated MoS2 composite material synthesized using this technique has a limited ability to withstand the volumetric strain of MoS2 during charge and discharge, thus its cycle life can only be improved to a limited extent. See the literature [Guilong Liu et al. 2D MoS2 grown on biomass-based hollow carbon fibers for energy storage.[J]. Applied Surface Science, 2019, 469: 854-863]. Liu et al. first prepared palm fiber biochar by calcination, then grew sulfides on the surface of the biochar using a hydrothermal method, and finally obtained the battery anode material by calcination. However, this method is relatively complicated, with multiple high-temperature calcinations increasing costs, and the binding force between the carbonized carbon base and the loaded sulfides is limited, resulting in poor cycle performance under long cycles and high currents. With the accelerated penetration of new energy vehicles, the continuous improvement of battery energy density, and the gradual increase in voltage platform, battery safety has become a major concern, and its importance is increasingly prominent. Anode materials are a key component of batteries. However, existing technical solutions do not mention the impact of anode materials on battery safety performance.

[0004] Lithium-sulfur batteries (LSBs) have a high theoretical specific capacity (1675 mAh g). -1 Sulfur, with its abundant elemental sulfur and environmentally friendly properties, has become a research hotspot in the energy storage industry. However, unlike the working principle of commercial LIBs, the sulfur cathode undergoes a more complex reaction during charging and discharging, involving multiple solid-liquid phase reactions. During discharge, sulfur is first reduced to polysulfides (S₂) soluble in the electrolyte. n 2- (4≤n≤8). As the discharge process continues, the polysulfides are further reduced to S. 2- or S2 2-Ultimately, insoluble Li₂S and Li₂S₂ are formed and adhere to the surface of the positive electrode. The charging process is a reversible process of the above reaction. Therefore, during the charging and discharging of LSBs, the active material is mostly in the form of polysulfides in the electrolyte. While the electrolyte carrying polysulfides reacts by gaining and losing electrons at the positive electrode during charging and discharging, it can also easily pass through the separator to reach the lithium anode and undergo a reduction reaction, resulting in low utilization of the active material. This behavior is called the "shuttle effect" of LSBs. The shuttle effect significantly reduces the electrochemical performance of LSBs, causing serious problems such as rapid battery capacity decay and low utilization of active material, thus greatly limiting the practical application of LSBs.

[0005] To address this, the literature [Tianyu Lei et al. Inhibiting polysulfide shuttling with a graphene composite separator for highly robust lithium-sulfur batteries.[J]. Joule, 2018, 2(10): 2091-2104; Yuhong Liu et al. 3D MXene architectures as sulfur hosts for high-performance lithium-sulfur batteries.[J]. Journal of Energy Chemistry, 2022, 66: 429-439.] provides a scheme to coat carbon materials such as graphene and porous carbon onto the surface of commercial separators to form a polysulfide physical barrier layer. However, carbon materials have weak polarity and poor interaction with polar LiPSs, resulting in limited effectiveness in capturing LiPSs. Therefore, batteries assembled with this type of modified separator exhibit rapid electrochemical performance degradation at high rates. See the reference [Zhiyong Zhang et al, Al2O3-coated porous separator for enhanced electrochemical performance of lithium sulfur batteries.[J]. Electrochimica Acta, 2014, 129:55-61]. Zhang et al. modified the separator with alumina, but due to the low affinity of alumina for polysulfides, the battery assembled with this modified separator only showed a first-cycle performance of 967.0 mAh g. -1The specific capacity. See the literature [Yoongon Kim et al. N-doped carbon-embedded TiN nanowires as a multifunctional separator for Li-S batteries with enhanced rate capability and cycle stability.[J]. Journal of Energy Chemistry, 2021, 57:10-18.]. Kim et al. first used electrospinning technology to obtain polymer fibers containing titanium sources, and then calcined them at high temperature under ammonia to obtain nitrogen-doped fiber structures coated with nano-titanium nitride, which were used for separator modification. This technical solution involves the use of high-voltage equipment, and the process is relatively complex. As a key component of the battery system, the physicochemical properties of the separator inevitably have a significant impact on battery safety performance. However, existing technical solutions have not been studied.

[0006] As is well known, batteries pose a risk of thermal runaway. Under abusive conditions, battery materials are highly susceptible to exothermic chemical reactions. When the rate of heat generation exceeds the rate of heat dissipation, internal heat accumulates continuously, causing the temperature to rise steadily. When the battery temperature reaches a threshold, thermal runaway occurs, rapidly releasing large amounts of heat and toxic or flammable gases, leading to combustion and explosion accidents, and causing significant harm to life and property. Therefore, it is essential to simultaneously improve the electrochemical and safety performance of batteries through the design of key battery materials. Summary of the Invention

[0007] To address the shortcomings of current commercial technologies, this invention provides a honeycomb carbon / bimetallic sulfide material, its preparation method, and its applications. The anode made from this multifunctional honeycomb carbon / bimetallic sulfide material, Fe-Sn-S@HC, exhibits superior cycle and rate performance compared to graphite anodes. Batteries using Fe-Sn-S@HC anodes show significantly lower peak temperatures during thermal runaway compared to batteries using graphite anodes, indicating that the risk of thermal runaway is effectively suppressed. Furthermore, by using Fe-Sn-S@HC modified commercial separators (Fe-Sn-S@HC@C), the electrochemical and safety performance of LSBs can be significantly improved, reducing the risk of battery thermal runaway.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] In a first aspect, the present invention provides a honeycomb carbon / bimetallic sulfide material, comprising a disc-shaped nano-bimetallic sulfide and a honeycomb porous carbon tightly encapsulating the nano-bimetallic sulfide, wherein the nano-bimetallic sulfide is tightly encapsulated in the connecting part of adjacent honeycomb structures; the average diameter of the honeycomb porous structure is 340 nm to 860 nm, and the particle size of the nano-bimetallic sulfide is 50 nm to 150 nm;

[0010] It should be noted that the nano-bimetallic sulfide described in this invention refers to two metal sulfides generated in situ, with a large number of phase boundaries between the two metal sulfides and abundant reaction sites. The two metal elements are any two metal elements selected from Fe, Sn, Cu, Co, Ni, Zn, Mo, and Mn.

[0011] Preferably, the nano-bimetallic sulfide is an iron-tin nano-bimetallic sulfide, Fe-Sn-S.

[0012] The present invention also provides a method for preparing the above-mentioned honeycomb carbon / bimetallic sulfide material, comprising the following steps: dissolving sodium chloride, iron salt, tin salt, sulfur source, and carbon source sequentially in deionized water, and mechanically stirring at 30-60°C for 2-6 hours; then freeze-drying the mixture to obtain a precursor; wherein the mass ratio of iron salt to sodium chloride is 1:(10-20), the mass ratio of iron salt to tin salt is 1:(0.1-10), the mass ratio of iron salt to sulfur source is 1:(0.5-5), and the mass ratio of iron salt to carbon source is 1:(0.5-5); heating the prepared precursor from room temperature (25°C), calcining it at 600-1000°C for 4-10 hours, cooling it, washing it with deionized water and ethanol, and drying it at 60-100°C to obtain Fe-Sn-S@HC;

[0013] The iron salt is one or two of ferric nitrate, ferric sulfate, ferric chloride, ferrous nitrate, and ferric hydroxide.

[0014] The tin salt is one or two of tin nitrate, tin oxalate, stannous sulfate, tin acetate, and tin sulfate.

[0015] The sulfur source is one or two of thiourea, thioacetamide, sulfur powder, and sodium sulfide.

[0016] The carbon source is one or two of glucose, fructose, chitosan, citric acid, oxalic acid, succinic acid, and tannic acid.

[0017] The calcination atmosphere is one of nitrogen, argon, or a hydrogen-argon mixture, wherein the volume percentage of hydrogen in the hydrogen-argon mixture is 5%.

[0018] Secondly, this invention provides the application of the above-mentioned honeycomb carbon / bimetallic sulfide material in the fabrication of battery negative electrodes. As a preferred application, this invention provides a battery negative electrode, the fabrication process of which includes the following steps: Fe-Sn-S@HC powder, acetylene black, polyvinylidene fluoride, and N-methylpyrrolidone are ground in a mortar for 15-45 minutes to obtain a slurry. The slurry is then coated onto copper foil with a scraper. After drying, the electrode sheet is punched into a circular electrode sheet, i.e., the Fe-Sn-S@HC electrode sheet. The mass ratio of Fe-Sn-S@HC powder, acetylene black, and polyvinylidene fluoride is one of 8:1:1, 7:2:1, or 6:3:1. The mass-volume ratio of Fe-Sn-S@HC powder to N-methylpyrrolidone is 1 mg:(20-50) μL. Preferably, the diameter of the circular electrode sheet is 12 mm to 13 mm.

[0019] Thirdly, the present invention provides an ion battery, wherein the ion battery is a lithium-ion battery (LIB) or a sodium-ion battery (SIB) using the above-mentioned Fe-Sn-S@HC electrode as the negative electrode.

[0020] Fourthly, this invention provides the application of the above-mentioned honeycomb carbon / bimetallic sulfide material in the manufacture of battery separators. As a preferred application, this invention provides a battery separator, the battery separator manufacturing process of which includes the following steps: ball milling Fe-Sn-S@HC powder, carbon black, polyvinylidene fluoride, and N-methylpyrrolidone into a uniform slurry; coating the milled uniform slurry onto a Celgard 2325 separator; drying; and obtaining Fe-Sn-S@HC@C separator discs using a punch, which is the battery separator of this invention; wherein, the mass ratio of Fe-Sn-S@HC powder, Super P, and polyvinylidene fluoride is one of 8:1:1, 7:2:1, or 6:3:1; and the mass-volume ratio of Fe-Sn-S@HC powder to N-methylpyrrolidone is 1 mg:(10-60) μL.

[0021] Preferably, the diameter of the diaphragm disc is 16.8 mm to 19 mm;

[0022] Preferably, the carbon black is either Super P or acetylene black.

[0023] Fifthly, the present invention provides a lithium-sulfur battery, wherein the lithium-sulfur battery is an LSB using the above-mentioned Fe-Sn-S@HC@C membrane disc as the separator.

[0024] Advantages and beneficial effects compared to existing technologies:

[0025] The honeycomb carbon / bimetallic sulfide material provided by this invention possesses a unique three-dimensional micro / nano structure. A honeycomb carbon micron-porous structure was obtained by removing the sodium chloride template. The in-situ reduction and sulfidation of metal ions during calcination led to the formation of nano-metal sulfides. Simultaneously, the honeycomb porous carbon tightly encapsulates the nano-metal sulfides. First, the porous structure buffers the volume change of the metal sulfides during ion insertion / extraction, shortening the ion transfer path and providing sufficient contact and enhanced charge transfer at the electrode-electrolyte interface. Second, the micro / nano structure of the honeycomb carbon / bimetallic sulfide material possesses the structural advantages of both nanoscale units and micron-scale clusters. The former shortens the ion diffusion path and increases electrochemical reaction sites, while the latter improves the structural stability of the material. Third, the interfacial effect of the bimetallic sulfide can introduce an internal electric field, improving reaction kinetics and providing abundant electrochemical reaction sites. The in-situ generated phase boundary can provide small crystal regions as hosts, reducing ion diffusion paths. Fourth, heteroatom-doped carbon not only effectively improves the overall conductivity of the structure but also suppresses sulfide volume expansion and particle pulverization behavior. The ion battery assembled using the honeycomb carbon / bimetallic sulfide material of this invention has excellent cycle and rate performance.

[0026] Furthermore, the porous structure of the honeycomb carbon / bimetallic sulfide material of this invention enables the full embedding and protection of active lithium, reducing the reaction between active lithium and the electrolyte during thermal runaway. Additionally, the metal elements in the honeycomb carbon / bimetallic sulfide material of this invention can catalyze carbon formation, promoting carbon layer formation and inhibiting the release of combustible pyrolysis products. Therefore, the ion battery assembled using the honeycomb carbon / bimetallic sulfide material of this invention exhibits higher safety performance.

[0027] The honeycomb carbon / bimetallic sulfide material of this invention possesses excellent electrical conductivity and a large specific surface area. The unique coordination environment of the metal provides abundant catalytic active sites, effectively capturing and catalyzing the conversion of polysulfides while accelerating electron transfer. Furthermore, the heteroatom-doped carbon structure exhibits excellent physical / chemical adsorption properties, further aiding in polysulfide capture. LSBs assembled with this membrane exhibit not only higher electrochemical performance compared to LSBs using commercial membranes, but also a significantly reduced risk of thermal runaway. Attached Figure Description

[0028] Figure 1 Here is a SEM image of Fe-Sn-S@HC@C in Example 1;

[0029] Figure 2 This is a TEM image of Fe-Sn-S@HC@C in Example 1;

[0030] Figure 3 The XRD pattern of Fe-Sn-S@HC@C in Example 1;

[0031] Figure 4 These are the cycle performance test results of the LIBs assembled in Example 3;

[0032] Figure 5 These are the cycle performance test results of the SIBs assembled in Example 4;

[0033] Figure 6 Here is an SEM image of the modified diaphragm prepared in Example 5;

[0034] Figure 7 These are the cycle performance test results of the LSBs assembled in Example 6;

[0035] Figure 8 This is a comparison of the maximum thermal runaway peak temperature of the LIBs assembled in Example 3;

[0036] Figure 9 This is a comparison of the maximum thermal runaway peak temperature of the SIBs assembled in Example 4;

[0037] Figure 10 This is a comparison of the maximum thermal runaway peak temperature of the LSBs assembled in Example 6. Detailed Implementation

[0038] The present invention will now be described in detail with reference to preferred embodiments to facilitate understanding of the invention by those skilled in the art. It is particularly important to note that the embodiments are merely illustrative of the invention and should not be construed as limiting the scope of protection of the invention. Non-essential improvements and adjustments made to the invention based on the above description should still fall within the scope of protection of the invention. Furthermore, all raw materials mentioned below, unless otherwise specified, are commercially available products; and all process steps or extraction methods not mentioned in detail are process steps or extraction methods known to those skilled in the art.

[0039] The sources of some of the raw materials and reagents involved in the following examples, comparative examples and test examples are as follows: ferric nitrate, nickel nitrate, thiourea, tannic acid, sulfur powder, polyvinylidene fluoride, and N-methylpyrrolidone were all purchased from Sinopharm Chemical Reagent Co., Ltd.; commercial graphite, acetylene black, Super P, Celgard 2325 diaphragm, glass fiber diaphragm, and electrolyte were all purchased from Duoduo Reagent Co., Ltd.

[0040] Example 1: Preparation of Fe-Sn-S@HC@C

[0041] Prepare Fe-Sn-S@HC@C according to the following steps:

[0042] Step 1: Dissolve 12.5g sodium chloride, 1.2g ferric nitrate, 1.2g tin nitrate, 2.4g thiourea, and 3.6g tannic acid sequentially in 100mL of deionized water and mechanically stir at 30℃ for 2 hours. Then freeze-dry the mixture to obtain the precursor.

[0043] Step 2: Place the precursor prepared in Step 1 in a muffle furnace and heat it in nitrogen from room temperature (25°C) to 800°C and maintain the temperature for 6 hours. After cooling, wash with deionized water and ethanol, and dry at 60°C to obtain Fe-Sn-S@HC.

[0044] Figure 1 SEM images of Fe-Sn-S@HC@C are presented. It can be seen that Fe-Sn-S@HC exhibits a distinct honeycomb structure. The aforementioned honeycomb structure of Fe-Sn-S@HC... Figure 2 This is also shown in the TEM electron microscope images, and in addition, such as Figure 2 As shown, the sulfide nanoparticles circled in the dashed box are tightly wrapped by the carbon layer.

[0045] Figure 3 The XRD pattern of Fe-Sn-S@HC@C shows the presence of FeS, SnS, and carbon, indicating the successful preparation of the bimetallic sulfide.

[0046] Example 2: Preparation of Fe-Sn-S@HC@C electrode sheets

[0047] The following steps were taken to prepare the Fe-Sn-S@HC@C electrode for an ion battery: 0.07g of Fe-Sn-S@HC@C powder prepared in Example 1, 0.02g of acetylene black, 0.01g of polyvinylidene fluoride, and 1400μL of N-methylpyrrolidone were weighed and ground in a mortar for 35 minutes to obtain a slurry. The slurry was then coated onto a copper foil with a scraper. After drying, the electrode was punched into a round disc with a diameter of 12mm. The obtained Fe-Sn-S@HC electrode was placed in a glove box for later use.

[0048] Example 3 Assembly of LIBs

[0049] Assemble LIBs according to the following steps: Assemble LIBs in a glove box. Place lithium sheet, Celgard 2325 separator, 80 μL electrolyte (1.0 M LiPF6 / EC:DEC = 1:1 Vol%), Fe-Sn-S@HC electrode prepared in Example 2, gasket, and spring in the negative electrode shell of a 2032 battery in sequence. Then place the positive electrode shell on top and press and seal it.

[0050] The performance of the LIBs assembled in Example 3 was tested using the Newway Battery Testing System. The cyclic test conditions were: the first 5 cycles at a rate of 0.1A g. -1Then use 1A g -1 Rate cycling, voltage 0.1-3V.

[0051] The LIBs cycle test results are as follows: Figure 4 As shown, at 0.1A g -1 At the given current density, the reversible specific capacity in the first cycle is 1338.8 mAh·g⁻¹, using 1 A g. -1 After 500 cycles at the specified current density, the capacity still retains 613.3 mAh·g. -1 Coulomb efficiency remains at around 99.2%.

[0052] Example 4 Assembly of SIBs

[0053] Assemble SIBs according to the following steps: Perform battery assembly in a glove box. Place sodium sheet, glass fiber separator, 80 μL electrolyte (1.0 M NaCF3SO3 / DIGLYME), Fe-Sn-S@HC electrode sheet prepared in Example 2, gasket, and spring sheet in the negative electrode shell of the 2032 battery in sequence. Then place the positive electrode shell on top and press and seal it.

[0054] The performance of the LIBs assembled in Example 3 was tested using the Newway Battery Testing System. The cyclic test conditions were: the first 5 cycles at a rate of 0.1A g. -1 Then use 1A g -1 Rate cycling, voltage 0.1-3V.

[0055] The cyclic performance of SIBs is as follows: Figure 5 As shown, a sodium-ion battery using Fe-Sn-S@HC electrodes has an efficiency of 0.1 A·g. -1 The first-cycle reversible specific capacity at the current density reached 972.1 mAh·g. -1 1A·g -1 After 430 cycles at current density, the capacity remained at 570.4 mAh·g. -1 Coulomb efficiency remained at approximately 99.8%.

[0056] Example 5: Preparation of Fe-Sn-S@HC@C membrane

[0057] The Fe-Sn-S@HC@C membrane was prepared according to the following steps: 0.07g of Fe-Sn-S@HC powder prepared in Example 1, 0.02g of Super P, 0.01g of polyvinylidene fluoride, and 1200μL of N-methylpyrrolidone were weighed and placed in a vibrating ball mill and ball-milled into a uniform slurry. The uniform slurry was coated onto a Celgard 2325 membrane using a scraper. After drying, a Fe-Sn-S@HC@C membrane with a diameter of 17mm was obtained by punching.

[0058] Figure 6 This is a SEM image of the Fe-Sn-S@HC@C membrane. It can be seen that the Fe-Sn-S@HC active material is uniformly distributed on the surface of the commercial membrane, forming a continuous barrier layer. Figure 6 The part inside the dashed box is labeled Fe-Sn-S@HC, and the part outside the dashed box is acetylene black and polyvinylidene fluoride;

[0059] Example 6 Assembly of LSBs

[0060] Assemble LSBs according to the following steps: Perform battery assembly in a glove box. Place lithium sheet, Fe-Sn-S@HC@C separator prepared in Example 5, 80 μL electrolyte (1M LiTFSI / DME:DOL=1:1Vol%), sulfur positive electrode sheet, gasket, and spring in the negative electrode shell of the 2032 battery in sequence. Then place the positive electrode shell on top and press and seal it.

[0061] The performance of the LSBs assembled in Example 6 was tested using the Newway Battery Testing System. The cycle test conditions were: the first 5 cycles at a rate of 0.1C, followed by cycling at a rate of 1C, with a voltage of 1.7-2.8V.

[0062] The cyclic performance of LSBs is as follows Figure 7 As shown, the battery using the Fe-Sn-S@HC@C separator achieved a first-cycle discharge specific capacity of 1251.7 mAh·g at 0.1C. -1 After 500 cycles at 1C, the capacity remains at 580.0 mAh·g. -1 Coulomb efficiency remained at approximately 99.9%.

[0063] Comparative Example 1

[0064] Assemble LIBs with graphite as the negative electrode according to the following steps: The only difference between the steps for assembling LIBs in Example 3 and the steps for assembling LIBs in this comparative example is that graphite electrode sheets are used instead of Fe-Sn-S@HC electrode sheets. All other operations are the same. The only difference between the graphite electrode sheets and the Fe-Sn-S@HC electrode sheets prepared in Example 2 is that commercially available graphite is used instead of Fe-Sn-S@HC powder in the graphite electrode sheets. All other parts are the same.

[0065] The LIBs assembled in Example 3 and Comparative Example 1 were tested using ARC to compare the exothermic characteristics of the thermal runaway process of the two batteries. The peak thermal runaway temperatures of the two batteries were as follows: Figure 8 As shown, the peak temperature of LIBs using graphite as the negative electrode is 508.5℃, while the peak temperature of the battery using Fe-Sn-S@HC electrode is 448.6℃, which is 59.9℃ lower than that of the graphite negative electrode battery. This indicates that using Fe-Sn-S@HC negative electrode can significantly suppress heat release during thermal runaway of LIBs and reduce the hazards of battery thermal runaway.

[0066] Comparative Example 2

[0067] Assemble SIBs with graphite as the negative electrode according to the following steps: The only difference between the steps for assembling SIBs in Example 4 and the steps for assembling SIBs in this comparative example is that graphite electrode sheets are used instead of Fe-Sn-S@HC electrode sheets. All other operations are the same. The only difference between the graphite electrode sheets and the Fe-Sn-S@HC electrode sheets prepared in Example 2 is that commercially available graphite is used instead of Fe-Sn-S@HC powder in the graphite electrode sheets. All other parts are the same.

[0068] The SIBs assembled in Example 4 and Comparative Example 2 were tested using ARC to compare the exothermic characteristics of the thermal runaway process of the two batteries. The peak thermal runaway temperatures of the two batteries were as follows: Figure 9 As shown, the peak temperature of SIBs using graphite as the negative electrode is 465.8℃, while the peak temperature of the battery using Fe-Sn-S@HC electrode is 423.5℃, which is 42.3℃ lower than that of the graphite negative electrode battery. This indicates that using the Fe-Sn-S@HC negative electrode can significantly suppress heat release during SIB thermal runaway and reduce the hazards of battery thermal runaway.

[0069] Comparative Example 3

[0070] The LSBs were assembled according to the following steps: The only difference between this comparative example and the LSBs assembled in Example 6 is that a Celgard 2325 membrane was used instead of a Fe-Sn-S@HC@C membrane. All other operations were the same.

[0071] The LSBs assembled in Example 6 and Comparative Example 3 were tested using ARC to compare the exothermic characteristics of the thermal runaway process of the two batteries. The peak thermal runaway temperatures of the two batteries were as follows: Figure 10 As shown, the peak temperature of LSBs using the Celgard 2325 separator was 485.7℃, while the peak temperature of the battery using the Fe-Sn-S@HC@C separator was 433.8℃, a reduction of 51.9℃ compared to the graphite anode battery. This indicates that using the Fe-Sn-S@HC@C separator can significantly suppress heat release during the thermal runaway process of LSBs.

Claims

1. A honeycomb carbon / bimetallic sulfide material, characterized in that, The honeycomb carbon / bimetallic sulfide material comprises disc-shaped nano-bimetallic sulfides and honeycomb porous carbon tightly encapsulating the nano-bimetallic sulfides, wherein the nano-bimetallic sulfides are tightly encapsulated in the connecting parts of adjacent honeycomb structures; the average diameter of the honeycomb porous structure is 340nm~860nm, the particle size of the nano-bimetallic sulfides is 50nm~150nm, and the bimetallic compound in the nano-bimetallic sulfides is Fe and Sn; that is, the nano-bimetallic sulfides are iron-tin bimetallic sulfides Fe-Sn-S. The preparation method of the honeycomb carbon / bimetallic sulfide material includes the following steps: dissolving sodium chloride, iron salt, tin salt, sulfur source, and carbon source sequentially in deionized water, and mechanically stirring at 30~60℃ for 2~6h; then freeze-drying the mixture to obtain a precursor; wherein, the mass ratio of iron salt to sodium chloride is 1:(10~20), the mass ratio of iron salt to tin salt is 1:(0.1~10), the mass ratio of iron salt to sulfur source is 1:(0.5~5), and the mass ratio of iron salt to carbon source is 1:(0.5~5); heating the prepared precursor from room temperature (25℃), calcining it at 600~1000℃ for 4~10h, cooling it, washing it with deionized water and ethanol, and drying it at 60~100℃ to obtain the honeycomb carbon / bimetallic sulfide material Fe-Sn-S@HC.

2. The honeycomb carbon / bimetallic sulfide material according to claim 1, characterized in that, The iron salt is one or two of ferric nitrate, ferric sulfate, ferric chloride, ferrous nitrate, and ferric hydroxide; the tin salt is one or two of tin nitrate, tin oxalate, stannous sulfate, tin acetate, and tin sulfate; the sulfur source is one or two of thiourea, thioacetamide, sulfur powder, and sodium sulfide; the carbon source is one or two of glucose, fructose, chitosan, citric acid, oxalic acid, succinic acid, and tannic acid; the calcination atmosphere is one of nitrogen, argon, and a hydrogen-argon mixture, wherein the volume percentage of hydrogen in the hydrogen-argon mixture is 5%.

3. The application of the honeycomb carbon / bimetallic sulfide material according to claim 1 in the fabrication of a battery negative electrode.

4. A battery negative electrode, characterized in that, The battery negative electrode manufacturing process includes the following steps: The powdered honeycomb carbon / bimetallic sulfide material of claim 1, namely Fe-Sn-S@HC powder, acetylene black, polyvinylidene fluoride, and N-methylpyrrolidone, are ground in a mortar for 15-45 minutes to obtain a slurry. The slurry is then scraped onto a copper foil using a scraper. After drying, the electrode sheet is punched into a circular electrode sheet, which is the battery negative electrode Fe-Sn-S@HC electrode sheet. The mass ratio of Fe-Sn-S@HC powder, acetylene black, and polyvinylidene fluoride is one of 8:1:1, 7:2:1, or 6:3:

1. The mass-volume ratio of Fe-Sn-S@HC powder to N-methylpyrrolidone is 1 mg:(20~50) μL.

5. An ion battery, characterized in that, The ion battery is a lithium-ion battery (LIB) or sodium-ion battery (SIB) using the negative electrode of the battery described in claim 4 as the negative electrode.

6. The application of the honeycomb carbon / bimetallic sulfide material according to claim 1 in the manufacture of battery separators.

7. A battery separator, characterized in that, The battery separator manufacturing process includes the following steps: The powdered honeycomb carbon / bimetallic sulfide material of claim 1, namely Fe-Sn-S@HC powder, carbon black, polyvinylidene fluoride, and N-methylpyrrolidone are ball-milled into a uniform slurry. The milled uniform slurry is coated onto a Celgard 2325 separator and dried. After drying, a Fe-Sn-S@HC@C separator disc is obtained by punching, which is the battery separator. The mass ratio of Fe-Sn-S@HC powder, Super P, and polyvinylidene fluoride is one of 8:1:1, 7:2:1, or 6:3:

1. The mass-volume ratio of Fe-Sn-S@HC powder to N-methylpyrrolidone is 1 mg: (10~60) μL.

8. A lithium-sulfur battery, characterized in that, The lithium-sulfur battery is manufactured using the battery separator described in claim 7 as the separator.

Images