Carbon cloth three-dimensional structure loaded zinc sulfide cobalt composite material and preparation method and application thereof
By loading zinc cobalt sulfide nanoparticles onto carbon cloth and encapsulating them with spiky titanium dioxide to form a three-dimensional structure of carbon cloth@ZnCo2S4@TiO2, the conductivity and cycle performance issues of lithium battery anode materials are solved, achieving a high-efficiency performance improvement for lithium-ion batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANJING UNIV OF POSTS & TELECOMM
- Filing Date
- 2026-01-30
- Publication Date
- 2026-05-01
AI Technical Summary
The existing lithium battery anode material, zinc cobalt sulfide, has poor conductivity and cycle performance, resulting in poor cycle stability and rate performance. Traditional composite methods have limited effectiveness.
A three-dimensional carbon cloth structure is used to support zinc cobalt sulfide composite material. By uniformly covering zinc cobalt sulfide nanoparticles on the carbon cloth carbon fibers and generating spiky titanium dioxide coatings on their surface, a three-dimensional carbon cloth@ZnCo2S4@TiO2 structure is formed.
It improves the conductivity and cycle stability of the material, enhances the diffusion ability of lithium ions, reduces the internal resistance of the battery, and exhibits long-term cycle stability and excellent rate performance.
Smart Images
Figure CN121964533A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of composite material technology, specifically relating to a three-dimensional carbon cloth-supported zinc cobalt sulfide composite material, its preparation method, and its application. Background Technology
[0002] Commercial lithium-ion batteries mostly use graphite systems as anodes. However, the relatively low theoretical lithium storage capacity of these materials limits the development of lithium-ion batteries towards higher specific energy and longer lifespan. Transition metal sulfides (TMS) have attracted significant attention as pseudocapacitive electrode materials due to their high theoretical specific capacity, diverse types, and environmental friendliness. Furthermore, bimetallic sulfides offer better stability, larger specific surface area, and better conductivity, providing more opportunities to improve electrode material performance. Because of the low electronegativity of sulfur and the weak metal-S bond, most TMSs exhibit stronger electron transfer capabilities than their corresponding oxides. In addition, the voltage and theoretical capacity of TMSs are easily tunable. However, the volume effect and slow kinetics of bimetallic sulfides during electrochemical reactions lead to poor cycle stability and rate performance. Morphology control or the addition of other materials is needed to mitigate their volume expansion.
[0003] Therefore, improving the conductivity and cycling stability of zinc cobalt sulfide materials is a key technical problem to be solved. Currently, the mainstream approaches fall into two categories. One is the design of nanoporous / hollow morphologies, where structures such as nanocages and nanosheets can significantly shorten the Li+ diffusion distance. However, electrode fabrication using this method requires a binder, resulting in lower conductivity. The other approach is to composite zinc cobalt sulfide with carbon materials, using materials such as graphene and carbon nanotubes. Carbon materials possess excellent conductivity, reducing stress during volume changes while improving stability. However, this method's effect on improving material stability is not ideal. Summary of the Invention
[0004] To improve the conductivity and cycle stability of zinc cobalt sulfide materials, this invention provides a three-dimensional carbon cloth-supported zinc cobalt sulfide composite material, its preparation method, and its application.
[0005] This invention provides a three-dimensional carbon cloth-supported zinc cobalt sulfide composite material, wherein the composite material is composed of carbon cloth, zinc cobalt sulfide nanoparticles, and spiky TiO2;
[0006] The carbon cloth is a carbon fiber substrate of a composite material. The carbon fiber rods of the carbon cloth are interwoven to form the carbon cloth. The zinc cobalt sulfide nanoparticles are uniformly covered on the carbon fiber rods of the carbon cloth, and the spiky titanium dioxide is wrapped and grown on the zinc cobalt sulfide nanoparticles.
[0007] Preferably, in the composite material, the mass percentage content of carbon cloth and titanium dioxide is 89-90%, and the mass percentage content of zinc cobalt sulfide nanoparticles is 10-11%.
[0008] Preferably, in the composite material, the zinc cobalt sulfide nanoparticles have a particle size of 20-30 nm; both TiO2 and carbon fiber rods are micron-sized, the titanium dioxide has a size of 1-2 μm, and the carbon fiber rods have a diameter of 2-5 μm.
[0009] The zinc cobalt sulfide is a material commonly used to prepare battery anodes, and it has the advantages of high specific capacity, low cost, and abundant resources.
[0010] This invention provides a method for preparing a three-dimensional carbon cloth-supported zinc cobalt sulfide composite material. The invention generates a carbon cloth@ZnCo2S4 precursor by coating uniformly granular zinc cobalt sulfide nanoparticles onto carbon fiber rods of carbon cloth, and synthesizes spiky titanium dioxide by a hydrothermal solvent method. The spiky titanium dioxide is encapsulated on the zinc cobalt sulfide nanoparticles of the carbon cloth@ZnCo2S4 precursor, thus forming a three-dimensional carbon cloth@ZnCo2S4@TiO2 composite material.
[0011] Specifically, the steps include the following:
[0012] Step S1: Soak the carbon cloth in a mixture of concentrated nitric acid and deionized water, then transfer it to a polytetrafluoroethylene-lined stainless steel autoclave, seal it, and carry out a hydrothermal reaction; then take out the carbon cloth, use ethanol as a cleaning solution to ultrasonically clean the carbon cloth for a period of time, adjust the pH of the cleaning solution to neutral, then wash it with deionized water, and then dry it in a vacuum dryer.
[0013] Step S2: Add Zn(NO3)2·6H2O, Co(NO3)2·6H2O, urea and thiourea to deionized water and stir to form a mixed solution;
[0014] Step S3: The mixed solution is transferred into a polytetrafluoroethylene-lined stainless steel autoclave, carbon cloth is added, the autoclave is sealed, and a hydrothermal reaction is carried out. After the reaction is completed, the carbon cloth is removed and washed with deionized water to obtain the precursor carbon cloth@ZnCo2S4 composite material.
[0015] S4: Add glycerol to anhydrous ethanol and mix and stir, then add tetrabutyl titanate and stir for a period of time to form a mixed solution; transfer the mixed solution into a polytetrafluoroethylene-lined stainless steel autoclave, and add the precursor carbon cloth@ZnCo2S4 composite material at the same time, seal and carry out hydrothermal reaction, then take out the carbon cloth, wash it with deionized water and vacuum dry it.
[0016] Step S5: Anneal the dried carbon cloth@ZnCo2S4@TiO2 under the protection of high-purity argon for a period of time to complete the preparation of the three-dimensional composite material.
[0017] Preferably, in step S1, the volume ratio of concentrated nitric acid to water is 5:35, the volume concentration of concentrated nitric acid is 65%-68%, and the optimal hydrothermal reaction conditions are: hydrothermal temperature 85℃, holding time 12h. The carbon cloth is ultrasonically cleaned with ethanol for 120 minutes, and the drying temperature during vacuum drying is 70℃.
[0018] Preferably, in step S2, the molar ratio of Zn(NO3)2·6H2O, Co(NO3)2·6H2O, urea and thiourea is 1:2:6:8.
[0019] Preferably, in step S3, the optimal hydrothermal reaction conditions are: a hydrothermal temperature of 170°C and a holding time of 12 hours. Under these conditions, the zinc cobalt sulfide on the carbon fiber surface is uniformly distributed without significant agglomeration. The temperature and time of the hydrothermal process in step S3 affect the formation and uniform distribution of zinc cobalt sulfide on the carbon fiber.
[0020] Preferably, in step S4, the optimal hydrothermal reaction conditions are: a hydrothermal temperature of 180°C and a holding time of 16 hours. Under these conditions, titanium dioxide is uniformly distributed without significant agglomeration.
[0021] Preferably, in step S4, the optimal hydrothermal reaction conditions in step S3 are: a hydrothermal temperature of 180°C and a holding time of 16 hours; and a volume ratio of glycerol, anhydrous ethanol, and tetrabutyl titanate of 5:25:0.2.
[0022] The amount of tetrabutyl titanate used, the temperature, and the holding time in step S4 affect the formation and stability of TiO2 morphology.
[0023] Preferably, the optimal annealing temperature in step S5 is 500℃, the optimal heating rate is 5℃ / min, and the temperature is maintained at 500℃ for 3 hours. Under these conditions, TiO2 has strong stability and good crystallinity.
[0024] Preferably, the three-dimensional structure consists of carbon fiber cloth and TiO2-encapsulated zinc cobalt sulfide nanoparticles. The zinc cobalt sulfide nanoparticles act as the active material, providing capacity.
[0025] This invention provides an application of a three-dimensional carbon cloth structure supporting an active material, which is used to prepare a lithium-ion battery anode.
[0026] The principle behind this invention's carbon cloth@ZnCo2S4@TiO2 three-dimensional material: Due to the volume effect and slow kinetics of zinc cobalt sulfides during electrochemical reactions, poor cycle stability and rate performance are resulting, hindering their practical application. To address these issues, and building upon previous research, this invention loads particulate zinc cobalt sulfide active materials onto carbon fibers, significantly improving conductivity. Simultaneously, it avoids the significant limitations imposed by uneven dispersion of active materials during electrode coating and the use of inactive components such as binders and conductive agents (conductive carbon black), forming a self-supporting structure.
[0027] To further improve the stability of the composite material, this invention introduces TiO2 onto the surface of a carbon cloth@ZnCo2S4 composite material. Titanium dioxide has advantages such as being green and low-cost, highly stable, and having zero structural strain; the spiky morphology of TiO2 has a high specific surface area and good stability, increasing the contact area with the electrolyte, shortening the lithium-ion diffusion distance, accelerating lithium-ion diffusion, and reducing battery impedance; combining ZnCo2S4 and TiO2 on a carbon cloth substrate to form a unique three-dimensional structure is an effective strategy for improving the electrochemical performance of lithium-ion batteries.
[0028] By using carbon cloth@ZnCo2S4@TiO2 three-dimensional material as a self-supporting electrode for lithium-ion batteries, good cycle stability was demonstrated, showing long-term cycle stability and excellent rate capability.
[0029] Beneficial effects:
[0030] (1) The present invention uniformly grows and covers ZnCo2S4 nanoparticles on carbon cloth carbon fiber rods, and generates TiO2 with a spiky structure on the surface of the nanoparticles for coating, while retaining the excellent conductivity of carbon fiber and the stability of TiO2; the introduction of TiO2 increases the contribution of surface pseudocapacitance and plays a synergistic effect to improve the electrochemical performance and mechanical stability of ZnCo2S4 composite material.
[0031] (2) The three-dimensional structure of the composite material of the present invention consists of three layers: a carbon fiber substrate, a ZnCo2S4 active nanoparticle middle layer, and a spiky TiO2 outer layer. The carbon fiber and the spiky TiO2 together encapsulate the ZnCo2S4 active nanoparticles, enabling the composite material to adapt to volume changes during charging and discharging, thereby increasing its mechanical properties. At the same time, the spiky outer layer effectively reduces the diffusion distance of lithium ions and increases the contact area between the electrode and the electrolyte.
[0032] The carbon cloth@ZnCo2S4@TiO2 three-dimensional structure possesses a high specific surface area, and the carbon fiber substrate provides excellent electrical conductivity for the composite material. This binder-free composite material exhibits long-term cycling stability and excellent rate capability.
[0033] (3) Using carbon cloth@ZnCo2S4@TiO2 three-dimensional material as a lithium-ion self-supporting flexible electrode, and using carbon cloth@ZnCo2S4@TiO2 three-dimensional material as negative electrode and lithium sheet as positive electrode to assemble a battery, it shows good cycle stability and rate performance, and has great application prospects in the preparation of lithium-ion flexible devices. Attached Figure Description
[0034] Figure 1 Scanning electron microscope (SEM) images of carbon cloth@ZnCo2S4 prepared under different hydrothermal temperatures and times.
[0035] Figure 2A Scanning electron microscope (SEM) images of carbon cloth@ZnCo2S4@TiO2 three-dimensional materials prepared at different hydrothermal temperatures and times with a titanate content of 0.1 mL.
[0036] Figure 2B Scanning electron microscope (SEM) images of carbon cloth@ZnCo2S4@TiO2 three-dimensional materials prepared at different hydrothermal temperatures and times with a titanate content of 0.2 mL.
[0037] Figure 2C Scanning electron microscope (SEM) images of carbon cloth@ZnCo2S4@TiO2 three-dimensional materials prepared at different hydrothermal temperatures and times with a titanate content of 0.3 mL.
[0038] Figure 3 Structural characterization of CC@ZnCo2S4@TiO2-spiky three-dimensional material.
[0039] Figure 4 Impedance testing and analysis of CC@ZnCo2S4@TiO2-spiky three-dimensional material.
[0040] Figure 5 Elemental analysis diagram of CC@ZnCo2S4@TiO2-spiky three-dimensional material.
[0041] Figure 6 A comparison of the low-current cycling performance of CC@ZnCo2S4@TiO2-spiky materials used in lithium-ion batteries.
[0042] Figure 7 The image shows the high-current cycling performance of CC@ZnCo2S4@TiO2-spiky three-dimensional material used in lithium-ion batteries.
[0043] Figure 8 The effect of CC@ZnCo2S4@TiO2-spiky on the rate cycle performance of lithium-ion batteries.
[0044] Figure 9The image shows the effect of using CC@ZnCo2S4@TiO2-spiky materials in different bending states of a pouch battery. Detailed Implementation
[0045] The technical solution of the present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited to the embodiments described.
[0046] Example 1
[0047] The steps for preparing carbon cloth@ZnCo2S4 composite material are as follows:
[0048] Step S1: Soak the carbon cloth (purchased from Shanghai Hesen, model HCP330N, hydrophilic) in 15ml of concentrated nitric acid (65% by volume) and 35ml of deionized water, then transfer it to a PTFE-lined stainless steel autoclave, seal it, and heat it to 85℃ for 12 hours; then remove the carbon cloth, ultrasonically clean it with ethanol for 120 minutes, adjust the pH to neutral, wash it with deionized water, and then dry it in a vacuum dryer;
[0049] Step S2: Add 1 mmol Zn(NO3)2·6H2O, 2 mmol Co(NO3)2·6H2O, 6 mmol urea and 8 mmol thiourea to 40 ml of deionized water and stir to form a mixed solution.
[0050] Step S3: Transfer the solution into a 100ml polytetrafluoroethylene-lined stainless steel autoclave, add 4cm×4cm carbon cloth, seal, and set the heating temperature and holding time to 150℃, 170℃, 190℃ and 10h, 12h, 14h respectively; remove the carbon cloth and wash it several times with deionized water to obtain carbon cloth@ZnCo2S4 composite material.
[0051] The prepared samples were characterized by SEM to determine whether ZnCo2S4 nanoparticles were uniformly grown and covered on carbon cloth carbon fiber rods, and whether there was any aggregation.
[0052] SEM characterization results are as follows: Figure 1 As shown, through observation, the carbon cloth@ZnCo2S4 composite material prepared under hydrothermal temperature of 170℃ for 12h has a relatively uniform distribution of nanoparticles. The ZnCo2S4 nanoparticles grow uniformly and cover the carbon fiber rods, with no uncovered areas or agglomeration.
[0053] Example 2
[0054] The three-dimensional composite material carbon cloth@ZnCo2S4@TiO2 was prepared by the following steps:
[0055] Step S1: Soak the carbon cloth in 15ml of concentrated nitric acid (65% by volume) and 35ml of deionized water, then transfer it to a PTFE-lined stainless steel autoclave, seal it, heat it to 85℃ and keep it at that temperature for 12 hours; then take out the carbon cloth, ultrasonically clean it with ethanol for 120 minutes, adjust the pH to neutral, wash it with deionized water, and then dry it in a vacuum dryer;
[0056] Step S2: Add 1 mmol Zn(NO3)2·6H2O, 2 mmol Co(NO3)2·6H2O, 6 mmol urea and 8 mmol thiourea to 40 ml of deionized water and stir to form a mixed solution.
[0057] Step S3: Transfer the solution into a 100ml polytetrafluoroethylene-lined stainless steel autoclave, add 4cm×4cm carbon cloth, seal, heat to 170℃ and keep warm for 12 hours, remove the carbon cloth, wash it several times with deionized water to obtain the precursor carbon cloth@ZnCo2S4 composite material, denoted as CC@ZnCo2S4.
[0058] Step S4: Add 5 ml of glycerol to 25 ml of anhydrous ethanol and mix. Then add tetrabutyl titanate and stir for 1 hour to form a mixed solution. Transfer the solution to a 50 ml PTFE-lined stainless steel autoclave, and simultaneously add the 4 cm * 4 cm precursor carbon cloth @ ZnCo2S4 composite material obtained in the previous step. Seal and carry out a hydrothermal reaction. After the reaction is complete, remove the carbon cloth, wash it with deionized water, and vacuum dry it at 70°C.
[0059] In step S4, carbon cloth@ZnCo2S4@TiO2 was prepared at titanate dosages of 0.1 ml, 0.2 ml, and 0.3 ml, hydrothermal temperatures of 160°C, 180°C, and 200°C, and heat treatment durations of 14 h, 16 h, and 18 h, respectively.
[0060] Step S5: The dried carbon cloth@ZnCo2S4@TiO2 is annealed at 500℃ for 3 hours at a rate of 5℃ / min under the protection of high-purity argon to complete the preparation of the three-dimensional composite material.
[0061] The relevant test results are as follows:
[0062] (1) The SEM characterization results of the prepared three-dimensional composite material are as follows: Figure 2A - Figure 2C As shown: Through observation, three three-dimensional composite materials with good surface morphology were obtained under the above conditions. The surface morphologies of titanium dioxide were needle-like (0.1 ml tetrabutyl titanate, 180℃, 18h), spiky (0.2 ml tetrabutyl titanate, 180℃, 16h), and plate-like (0.3 ml tetrabutyl titanate, 180℃, 16h).
[0063] like Figure 2A As shown, when using 0.1 ml of tetrabutyl titanate, after holding at 160℃, 180℃, and 200℃ for 14 h, and at 160℃ for 16 h, titanium dioxide was not uniformly coated on the surface of CC@ZnCo2S4, with some uncoated areas. After holding at 160℃ for 18 h and 180℃ for 16 h, a small amount of titanium dioxide coated on the surface of CC@ZnCo2S4 agglomerated. After holding at 200℃ for 16 h and 18 h, a large amount of titanium dioxide coated on the surface of CC@ZnCo2S4 agglomerated. Holding at 180℃ for 18 h yielded needle-like titanium dioxide uniformly coated on the surface of CC@ZnCo2S4.
[0064] like Figure 2B As shown, with 0.2 ml of tetrabutyl titanate, after holding at 160℃, 180℃, and 200℃ for 14 h, and at 160℃ for 16 h, titanium dioxide was not uniformly coated on the surface of CC@ZnCo2S4, with some uncoated areas. After holding at 160℃ and 180℃ for 18 h, a small amount of titanium dioxide coated on the surface of CC@ZnCo2S4 agglomerated. After holding at 200℃ for 16 h and 18 h, a large amount of titanium dioxide coated on the surface of CC@ZnCo2S4 agglomerated. Holding at 180℃ for 16 h yielded a uniformly coated surface of spiky titanium dioxide on the surface of CC@ZnCo2S4.
[0065] like Figure 2C As shown, with 0.3 ml of tetrabutyl titanate, after holding at 160℃, 180℃, and 200℃ for 14 h, titanium dioxide was not uniformly coated on the surface of CC@ZnCo2S4, with some uncoated areas. After holding at 160℃ and 200℃ for 16 h, a small amount of titanium dioxide coated on the surface of CC@ZnCo2S4 agglomerated. After holding at 160℃, 180℃, and 200℃ for 18 h, a large amount of titanium dioxide coated on the surface of CC@ZnCo2S4 agglomerated. Holding at 180℃ for 16 h yielded uniformly coated flake-like titanium dioxide on the surface of CC@ZnCo2S4.
[0066] (2) The prepared three-dimensional composite materials, needle-shaped (0.1 ml tetrabutyl titanate, 180℃, 18h, annealed at 500℃ for 3 hours), spiky (0.2 ml tetrabutyl titanate, 180℃, 16h, annealed at 500℃ for 3 hours) and sheet-like (0.3 ml tetrabutyl titanate, 180℃, 16h, annealed at 500℃ for 3 hours) carbon cloth @ZnCo2S4@TiO2, are denoted as CC@ZnCo2S4@TiO2-needle-shaped, CC@ZnCo2S4@TiO2-spiky-shaped, and CC@ZnCo2S4@TiO2-sheet-shaped.
[0067] Figure 3Structural characterization of CC@ZnCo2S4@TiO2-spiky three-dimensional material. Figure 5 Elemental analysis diagram of CC@ZnCo2S4@TiO2-spiky three-dimensional material.
[0068] Preparation method of ZnCo2S4@TiO2: 1 mmol Zn(NO3)2·6H2O, 2 mmol Co(NO3)2·6H2O, 6 mmol urea, and 8 mmol thiourea were added to 40 ml of deionized water and stirred to form a mixed solution. The solution was transferred to a 100 ml PTFE-lined stainless steel autoclave, sealed, and heated to 170 °C for 12 hours. The product was removed and placed in a 50 ml centrifuge tube. Deionized water was added as a solvent, and the centrifugation speed was set to 10000 rpm for 10 min. After three centrifugations, the product was removed and vacuum dried at 70 °C for 12 h to obtain ZnCo2S4. 5 ml glycerol was added to 25 ml anhydrous ethanol and stirred. Then 0.2 ml tetrabutyl titanate was added and stirred for 1 hour to form a mixed solution. The solution was transferred to a 50 ml PTFE-lined stainless steel autoclave, and the ZnCo2S4 obtained in the previous step was added. The autoclave was sealed and heated to 180 °C for 16 h. The product was then removed and placed in a 50 ml centrifuge tube. Deionized water was added as a solvent, and the centrifugation speed was set to 10,000 rpm for 10 min. After three centrifugations, the product was removed and vacuum dried at 70 °C for 12 h to obtain ZnCo2S4@TiO2. The product was then annealed at 500 °C for 3 h at a rate of 5 °C / min under the protection of high-purity argon to complete the preparation of ZnCo2S4@TiO2.
[0069] Figure 4 The impedance test results are for CC@ZnCo2S4@TiO2-spiky three-dimensional materials. Figure 4 In this context, CC@ZnCo2S4 is an S3 product; Figure 4The corresponding electrochemical impedance spectroscopy (EIS) method was as follows: Lithium-ion battery assembly was performed using CR2032 coin cells. Prepared CC@ZnCo2S4, ZnCo2S4@TiO2, and CC@ZnCo2S4@TiO2-spiky electrodes were used directly as working electrodes, with lithium foil as the counter electrode. Both electrodes were cut into 12mm diameter discs, with an active material loading of approximately 1.5mg on the carbon cloth. Celgard 2500 was used as the separator, and 1M LiPF6 was added to a mixture of ethylene carbonate (EC) / diethyl carbonate (DEC) / dimethyl carbonate (DMC) (volume ratio 1:1:1) as the electrolyte. The battery assembly was conducted in an argon-filled glove box, maintaining H2O and O2 levels below 0.1ppm. The assembled battery was allowed to stand for 10 hours before being installed on an electrochemical workstation. The voltage window was set to 0.01-3 V, the test frequency range to 0.01 Hz-100 kHz, and the scan rate to 0.1 mV / s. -1 An electrochemical workstation applies a small-amplitude AC sinusoidal potential wave to the electrochemical system and measures the ratio of the AC potential to the current signal, i.e., the system impedance. The measured impedance data are plotted as a Nyquist diagram. By comparison, it can be seen that the CC@ZnCo2S4@TiO2- spikes have relatively small impedance.
[0070] Elemental composition analysis and SEM characterization:
[0071] In CC@ZnCo2S4@TiO2-needle-like structures, the mass percentage content of carbon cloth and titanium dioxide is 85-87%, and the mass percentage content of zinc cobalt sulfide nanoparticles is 13-15%; the particle size of the zinc cobalt sulfide nanoparticles is 20-30 nm, the size of the titanium dioxide is 2-3 μm, and the diameter of the carbon fiber rod is 2-5 μm.
[0072] In CC@ZnCo2S4@TiO2-spiky form, the mass percentage content of carbon cloth and titanium dioxide is 89-90%, and the mass percentage content of zinc cobalt sulfide nanoparticles is 10-11%; the particle size of the zinc cobalt sulfide nanoparticles is 20-30nm, the size of the titanium dioxide is 1-2μm, and the diameter of the carbon fiber rod is 2-5μm.
[0073] In the CC@ZnCo2S4@TiO2-sheet form, the mass percentage content of carbon cloth and titanium dioxide is 91-92%, and the mass percentage content of zinc cobalt sulfide nanoparticles is 8-9%; the particle size of the zinc cobalt sulfide nanoparticles is 20-30nm, the size of the titanium dioxide is 1-2μm, and the diameter of the carbon fiber rod is 2-5μm.
[0074] Example 3
[0075] The three types of carbon cloth three-dimensional structure-supported zinc cobalt sulfide composite materials prepared in Example 2 were used as negative electrodes to fabricate lithium-ion batteries, and the battery performance was tested.
[0076] 1) Lithium-ion battery assembly: Electrochemical tests were conducted using CR2032 coin cells. The prepared carbon cloth@ZnCo2S4@TiO2 was used directly as the working electrode, and lithium foil as the counter electrode. Both electrodes were cut into 12mm diameter discs, with an active material loading of approximately 1.5mg on the carbon cloth. Celgard 2500 was used as the separator, and 1M LiPF6 was added to a mixture of ethylene carbonate (EC) / diethyl carbonate (DEC) / dimethyl carbonate (DMC) (volume ratio 1:1:1) as the electrolyte. The battery was assembled in an argon-filled glove box, with H2O and O2 contents maintained below 0.1ppm.
[0077] 2) Battery testing:
[0078] The assembled lithium-ion batteries underwent performance testing, and the test results are as follows: Figure 6 As shown in Figure A, the discharge specific capacities of the needle-like, spiky, and sheet-like three-dimensional composite materials after 100 cycles at a current of 1 A / g are 1358.8, 1164.2, 848.1, and 1359.65 mA hg, respectively. -1 The capacity retention rates were 87.9%, 74.8%, and 54.5%, respectively, indicating that the three-dimensional composite material with a spiky morphology exhibits good cycling performance. Figure 6 As shown in Figure B, after 100 cycles at a current of 1 A / g, the CC@ZnCo2S4@TiO2 spikes exhibit high capacity retention, with a coulombic efficiency (CE) approaching 100%. Figure 6 As shown in Figure C, after 100 cycles at a current of 1 A / g, the CC@ZnCo2S4@TiO2 spiky composite exhibits high capacity retention, with a coulombic efficiency (CE) approaching 100%. This demonstrates that the composite material possesses good cycling stability.
[0079] Figure 7 This image shows the high-current cycling performance of CC@ZnCo2S4@TiO2-spiky 3D material in lithium-ion batteries. Figure 7 As shown in Figure A, it can be observed that after 200 cycles at a current density of 3 A / g, the specific capacity of CC@ZnCo2S4@TiO2- spike discharge is 1043.68 mAh g. -1 Compared to CC@ZnCo2S4 without titanium dioxide coating, it exhibits higher cycle stability. For example... Figure 7As shown in Figure B, after 200 cycles at a current density of 5 A / g, the specific capacity of CC@ZnCo2S4@TiO2- spike discharge is 771.6 mAh g. -1 .like Figure 7 The charge / discharge fitting graph of the CC@ZnCo2S4@TiO2 battery is shown below. Discharge is the discharge curve, and Charge is the charging curve. After 900 cycles at a current density of 8 A / g, the specific capacity of CC@ZnCo2S4@TiO2- in the spike discharge mode is 313.73 mAh g. -1 The capacity retention rate was 82.52%, the charge-discharge curves almost overlapped, and the coulombic efficiency (CE) was close to 100% except for the first cycle, demonstrating good cycle stability.
[0080] Figure 8 The effect of CC@ZnCo2S4@TiO2-spiky structure on rate cycling performance in lithium-ion batteries. For example... Figure 8 The figure shows the rate performance of the battery at different current densities. It can be seen that the battery exhibits good rate performance at current densities of 1 A / g, 2 A / g, 3 A / g, 4 A / g, 5 A / g, 6 A / g, 7 A / g, and 8 A / g, with reversible capacities of 1600.2, 1377.8, 1146, 953.2, 760.2, 579.4, 480.1, and 395.6 mAh g, respectively. -1 .
[0081] Figure 9 The images show the effects of CC@ZnCo2S4@TiO2 spikes on pouch cells under different bending conditions. Figures a, b, c, and d show the voltage test results of the pouch cells after bending at 0°, 90°, 180°, and after bending, respectively. As shown in figure a, after the prepared pouch cell was left to stand for 12 hours, its voltage was measured at 2.83V. After a 90° bend, as shown in figure b, its voltage was measured at 2.96V. After a 180° bend, as shown in figure c, its voltage was measured at 2.99V. After a 180° bend and returning to 0°, its voltage was measured at 2.87V. Figures e, f, g, and h verify that the pouch cell can still supply power normally after flexible deformation. These results indicate that the carbon cloth@ZnCo2S4@TiO2 composite material has great potential in high-capacity and high-stability lithium-ion batteries.
[0082] As described above, although the invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the invention.
Claims
1. A three-dimensional carbon cloth-supported zinc cobalt sulfide composite material, characterized in that, The composite material is composed of carbon cloth, zinc cobalt sulfide nanoparticles, and spiky TiO2. The carbon cloth is a carbon fiber substrate of a composite material. The carbon fiber rods of the carbon cloth are interwoven to form the carbon cloth. The zinc cobalt sulfide nanoparticles are uniformly covered on the carbon fiber rods of the carbon cloth, and the spiky titanium dioxide is wrapped and grown on the zinc cobalt sulfide nanoparticles.
2. The composite material according to claim 1, characterized in that, The carbon cloth and titanium dioxide together have a mass percentage content of 89-90%, and the zinc cobalt sulfide nanoparticles have a mass percentage content of 10-11%. The particle size of the zinc cobalt sulfide nanoparticles is 20-30 nm. The TiO2 and carbon fiber rods are both micron-sized, the titanium dioxide has a size of 1-2 μm, and the carbon fiber rods have a diameter of 2-5 μm.
3. A method for preparing the three-dimensional carbon cloth-supported zinc cobalt sulfide composite material as described in claim 1, characterized in that, Includes the following steps: S1. Soak the carbon cloth in a mixture of concentrated nitric acid and deionized water, then transfer it to a polytetrafluoroethylene-lined stainless steel autoclave, seal it, and carry out a hydrothermal reaction. Then, use ethanol as a cleaning solution to ultrasonically clean the carbon cloth for a period of time, adjust the pH of the cleaning solution to neutral, wash it with deionized water, and then dry it in a vacuum. S2. Add Zn(NO3)2·6H2O, Co(NO3)2·6H2O, urea and thiourea to deionized water and stir to form a mixed solution; S3. Transfer the mixed solution obtained in S2 into a polytetrafluoroethylene-lined stainless steel autoclave, add carbon cloth, seal, and carry out hydrothermal reaction. After the reaction is completed, remove the carbon cloth and wash it with deionized water to obtain the precursor carbon cloth@ZnCo2S4 composite material. S4. Add glycerol to anhydrous ethanol and mix and stir, then add tetrabutyl titanate and stir for a period of time to form a mixed solution; The mixed solution was transferred into a polytetrafluoroethylene-lined stainless steel autoclave, and the precursor carbon cloth@ZnCo2S4 composite material was added at the same time. The autoclave was sealed and hydrothermal reaction was carried out. Then the carbon cloth was taken out, washed with deionized water, and vacuum dried. S5. The dried carbon cloth@ZnCo2S4@TiO2 is annealed for a period of time under the protection of high-purity argon to obtain a three-dimensional carbon cloth-supported zinc cobalt sulfide composite material.
4. The preparation method according to claim 3, characterized in that, In step S1, the volume ratio of concentrated nitric acid to water is 5:35, the volume concentration of concentrated nitric acid is 65%-68%, and the hydrothermal reaction conditions are: hydrothermal temperature 85℃, heat preservation for 12h; the carbon cloth is ultrasonically cleaned with ethanol for 120 minutes, and the drying temperature in vacuum drying is 70℃.
5. The preparation method according to claim 3, characterized in that, In S2, the molar ratio of Zn(NO3)2·6H2O, Co(NO3)2·6H2O, urea and thiourea is 1:2:6:
8.
6. The preparation method according to claim 3, characterized in that, In S3, the hydrothermal reaction conditions are: hydrothermal temperature of 170℃, and holding time of 12 hours.
7. The preparation method according to claim 3, characterized in that, In S4, the hydrothermal reaction conditions are: hydrothermal temperature of 180℃, held for 16 hours; and the volume ratio of glycerol, anhydrous ethanol and tetrabutyl titanate is 5:25:0.
2.
8. The preparation method according to claim 3, characterized in that, Annealing conditions in S5: After reaching 500℃ at a heating rate of 5℃ / min, hold at 500℃ for 3 hours.
9. The application of the carbon cloth three-dimensional structure supported zinc cobalt sulfide composite material as described in claim 1 in the preparation of lithium-ion battery anodes.