High-first-effect tin disulfide-based integrated electrode
By growing multi-element doped high-entropy tin disulfide nanosheets on the conductive carbon cloth substrate, a three-dimensional grid structure is formed, which solves the problem of insufficient performance of the tin disulfide negative electrode material, and improves the Coulomb efficiency and cycle stability of lithium-ion batteries. sex.
Patent Information
- Application Number
- CN202410968515.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-19
- Publication Date
- 2024-12-17
AI Technical Summary
The negative electrode material of tin disulfide (SnS2) has problems in lithium-ion batteries with low Coulomb efficiency, large volume changes, low electronic conductivity and reduced tin utilization for the first time, resulting in poor electrochemical performance.
By growing multi-element doping on the conductive carbon cloth substrate, a high-entropy Sn1-x(MoFeCoNiV)xS2 nanosheets are formed, forming a three-dimensional grid structure, increasing layer spacing and defects, promoting rapid transmission of lithium ions and electron transfer, and avoiding tin aggregation improves electrochemical cycle stability.
It significantly improves the first Coulomb efficiency and reversible capacity of lithium-ion batteries, enhances the cycle stability and rate performance of the battery, and solves the problem of insufficient performance of the negative electrode material of lithium-ion batteries.
Smart Images
Figure CN119153625A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of electrode materials and electrochemical energy storage devices, and specifically relates to the preparation and application of a high initial efficiency tin disulfide-based integrated electrode. The integrated electrode is synthesized by a hydrothermal method and exhibits the characteristics of high initial efficiency and high reversible capacity when applied to negative electrode materials of lithium-ion batteries. Background Art
[0002] In recent years, with the growing demand for continuous and reliable energy supply, new energy technologies such as solar energy, nuclear energy, wind energy, geothermal energy and biomass energy have achieved unprecedented development. Although they have each contributed to the energy crisis, these energy sources face a common challenge: the inability to achieve continuous energy supply. The discontinuity of production capacity has prompted people to research and develop large-scale energy storage devices. Lithium-ion batteries have been widely used due to their high energy density, long life and low self-discharge characteristics, and have become the preferred device for energy storage.
[0003] Tin disulfide (SnS2) negative electrode materials have the characteristics of high theoretical capacity and abundant resources. They can meet the needs of high-performance lithium-ion batteries and have become a hot topic in the current research of negative electrode materials for lithium-ion batteries. However, SnS2 negative electrode materials also have some disadvantages, such as low initial coulombic efficiency; large volume changes during the charge and discharge process, resulting in gradual pulverization of the electrode; low intrinsic electronic conductivity of SnS2, making the rate performance not very ideal; and at the same time, during the first discharge, SnS2 is reduced to single-substance Sn, which is prone to aggregation, resulting in reduced utilization of Sn and too fast attenuation of reversible capacity.
[0004] In recent years, a new type of material called high entropy material (HEM) has been rapidly developed and widely concerned. HEM originated from high entropy alloys and has expanded to many fields, such as high entropy catalysts, high entropy ceramics, and also to electrode materials. The doping of multiple elements in high entropy electrode materials can produce a "cocktail effect". The synergistic effect between different metal cations can effectively improve the ion mobility, thereby effectively improving the electrochemical performance of the material. However, high entropy tin disulfide-based negative electrode materials have not been reported. Therefore, the research and development of high entropy tin disulfide-based materials and their application in lithium-ion battery negative electrode materials has positive practical significance for accelerating the development of tin disulfide-based negative electrode materials. Summary of the invention
[0005] The present invention aims to solve the shortcomings of SnS2 by directly growing multi-element doped SnS2 with high entropy on a conductive carbon cloth (CC) substrate. 1-x (MoFeCoNiV) xS2 nanosheets, multi-element doping not only increases the entropy of the material to form a high-entropy material, but the synergistic effect between the doped ions can effectively inhibit the aggregation of tin during the charge and discharge process, effectively alleviate the volume change problem, and can increase the interlayer spacing of the nanosheets and form abundant defects. Expanding the interlayer spacing is conducive to the rapid transmission of lithium ions, and the defects provide more lithium storage sites for the material. The integrated electrode grows the active material directly on the conductive substrate. The active material is in direct contact with the current collector and is not easy to fall off. In addition, the integrated electrode does not require the addition of adhesives and conductive agents. The electrode skeleton structure is more open and the electrochemical cycle stability is better. Carbon cloth is used as a conductive network to grow the active material, which is composed of a conductive substrate carbon cloth and an ultra-thin high-entropy Sn 1-x (MoFeCoNiV) x The three-dimensional grid structure formed by S2 nanosheets and the ultra-thin nanosheets shorten the transmission distance of lithium ions and provide sufficient space for the rapid embedding and de-embedding of lithium ions. Electrons can be effectively transferred in electrochemical reactions, which not only improves the first Coulomb effect, but also improves the reversible capacity and cycle stability of the battery, thereby improving the overall performance of the battery.
[0006] To achieve the above objectives, CC@Sn was prepared by a simple one-step hydrothermal method. 1-x (MoFeCoNiV) x The steps of S2 integrated electrode are:
[0007] (1) The commercial carbon cloth was cut into small pieces. The carbon cloth was ultrasonically cleaned in dilute nitric acid, and then ultrasonically cleaned in deionized water and anhydrous ethanol respectively. After drying, it was used in the next experiment.
[0008] (2) According to the ratio in the molecular formula, the corresponding metal salts of Sn, Mo, Fe, Co, Ni and V were weighed and dissolved in deionized water. After stirring and dissolving, L-cysteine was added and stirring was continued to obtain a mixed solution.
[0009] (4) The mixed solution of step (2) is transferred to a reaction kettle, and the carbon cloth obtained after the treatment of step (1) is added. The reaction kettle is sealed and transferred to a forced air drying oven, and the temperature is raised to 160-180° C., and then the reaction is carried out at a constant temperature for 6-10 hours, and then the temperature is lowered to room temperature.
[0010] (5) The carbon cloth after the reaction in step (4) is ultrasonically cleaned with deionized water and anhydrous ethanol, and then dried to obtain an integrated electrode CC@Sn 1-x (MoFeCoNiV) x S2.
[0011] The integrated electrode can be directly applied to lithium-ion batteries without adding adhesives and conductive agents, which is beneficial to improving the overall energy density of the battery. The preparation conditions involved in the present invention are simple, the raw materials are easily available, and it is easy to expand production. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 This is a scanning electron microscope image of the commercial carbon cloth used in the present invention. From the image, it can be seen that the surface of the carbon fibers on the carbon cloth is smooth and flat.
[0013] Figure 2 The integrated electrode CC@Sn obtained in Example 2 of the present invention 0.7 (MoFeCoNiV) 0.3 SEM image of S2. Compared with the original carbon cloth ( Figure 1 ) After the hydrothermal reaction, the surface of the carbon fibers on the carbon cloth is completely covered with multi-element doped Sn 0.7 (MoFeCoNiV) 0.3 S2 ultrathin nanosheets.
[0014] Figure 3 To peel off Sn from the integrated electrode of Example 2 of the present invention 0.7 (MoFeCoNiV) 0.3 High-resolution transmission electron microscopy image of S2 nanosheets. The interplanar spacing of the lattice fringes in the image is 6.2 Å, corresponding to Sn 0.7 (MoFeCoNiV) 0.3 The (001) crystal plane of the S2 nanosheet is larger than the interplanar spacing of the (001) crystal plane in the SnS2 standard card (5.89 Å). The expansion of the interplanar spacing is conducive to the transmission of lithium ions. The white circles in the figure mark the discontinuous defects of the crystal plane. The abundant defects provide more reaction sites for storing lithium ions, which will be beneficial to improving the capacity of the electrode.
[0015] Figure 4 The integrated electrode CC@Sn obtained in Example 3 of the present invention 0.5 (MoFeCoNiV) 0.5 SEM image of S2. As can be seen from the image, when the multi-element doping increases, the sample cannot maintain the morphology of nanosheets.
[0016] Figure 5 The integrated electrode CC@Sn obtained in Example 2 0.7 (MoFeCoNiV) 0.3 The first voltage-capacity curve of S2 at 1C rate. The discharge capacity of the first cycle is 1301.2 mAh g -1 , charging capacity is 1231.8 mAh g -1 , the Coulomb efficiency is as high as 94.7%.
[0017] Figure 6 The integrated electrode CC@Sn obtained in Example 2 0.7 (MoFeCoNiV) 0.3The cycling performance diagram of S2 at 1 C rate shows that the material still has a reversible specific capacity of 1011.4 mAh / g after 100 cycles, and the coulombic efficiency is as high as 99.1%, indicating that the material has good cycling stability.
[0018] Figure 7 The integrated electrode CC@Sn obtained in Example 2 0.7 (MoFeCoNiV) 0.3 Rate performance diagram of S2. At current densities of 0.2 C, 0.5 C, 1 C, 2 C, 5 C and 10 C, the discharge specific capacity reached 1686.6, 1581.3, 1360.4, 1254.2, 1011.4 and 670.8 mAh / g, respectively. When the current returned to 0.2 C, the charge specific capacity was 1686.1 mAh / g, which basically returned to the capacity of the first cycle. This shows that the integrated electrode obtained by the present invention has a high reversible capacity and good rate reversibility at high rates. DETAILED DESCRIPTION
[0019] In order to make the purpose, technical solutions and advantages of the present invention more clear, specific implementation modes are given below to further illustrate the present invention, but the protection scope of the present invention is not limited to the following embodiments.
[0020] Example 1
[0021] (1) Commercial carbon cloth was cut into small pieces of 2 cm × 4 cm, ultrasonically treated in 1 mol / L dilute nitric acid for 30 min, then ultrasonically cleaned in deionized water and anhydrous ethanol for 5 min respectively, and finally dried at 60 °C.
[0022] (2) Based on 1 mmol Sn 0.9 (MoFeCoNiV) 0.1 S2: 0.9 mmol tin chloride pentahydrate, 0.02 mmol ammonium molybdate, 0.02 mmol nickel nitrate, 0.02 mmol cobalt nitrate, 0.02 mmol ferric chloride, and 0.02 mmol ammonium metavanadate were respectively weighed and dissolved in 30 mL deionized water. After stirring for 20 minutes, 5 mmol L-cysteine was added and stirring was continued for 10 minutes to obtain a mixed solution.
[0023] (4) The mixed solution of step (2) was transferred to a 50 mL reactor, and the carbon cloth obtained after the treatment of step (1) was added. The reactor was sealed and transferred to a forced air drying oven. The temperature was raised to 180°C at a rate of 2°C / min, and then the reaction was kept at this temperature for 6 hours, and then the temperature was lowered to room temperature at a rate of 2°C / min.
[0024] (5) The carbon cloth after the reaction in step (4) was ultrasonically cleaned with deionized water and anhydrous ethanol for 30 seconds, and then dried at 80°C to obtain an integrated electrode CC@Sn 0.9 (MoFeCoNiV) 0.1 S2.
[0025] Example 2
[0026] (1) Commercial carbon cloth was cut into small pieces of 2 cm × 4 cm, ultrasonically treated in 2 mol / L dilute nitric acid for 30 min, then ultrasonically cleaned in deionized water and anhydrous ethanol for 5 min respectively, and finally dried at 60 °C.
[0027] (2) Based on 1 mmol Sn 0.7 (MoFeCoNiV) 0.3 S2: 0.7 mmol tin chloride pentahydrate, 0.06 mmol ammonium molybdate, 0.06 mmol nickel nitrate, 0.06 mmol cobalt nitrate, 0.06 mmol ferric chloride, and 0.06 mmol ammonium metavanadate were respectively weighed and dissolved in 30 mL deionized water. After stirring for 20 minutes, 5 mmol L-cysteine was added and stirring was continued for 10 minutes to obtain a mixed solution.
[0028] (4) The mixed solution of step (2) was transferred to a 50 mL reactor, and the carbon cloth obtained after the treatment of step (1) was added. The reactor was sealed and transferred to a forced air drying oven. The temperature was raised to 160°C at a rate of 2°C / min, and then the reaction was kept at this temperature for 10 hours, and then the temperature was lowered to room temperature at a rate of 2°C / min.
[0029] (5) The carbon cloth after the reaction in step (4) was ultrasonically cleaned with deionized water and anhydrous ethanol for 30 seconds, and then dried at 80°C to obtain an integrated electrode CC@Sn 0.7 (MoFeCoNiV) 0.3 S2.
[0030] Example 3
[0031] (1) Commercial carbon cloth was cut into small pieces of 2 cm × 4 cm, ultrasonically treated in 1 mol / L dilute nitric acid for 30 min, then ultrasonically cleaned in deionized water and anhydrous ethanol for 5 min respectively, and finally dried at 60 °C.
[0032] (2) Based on 1 mmol Sn 0.5 (MoFeCoNiV) 0.5S2: 0.5 mmol tin chloride pentahydrate, 0.1 mmol ammonium molybdate, 0.1 mmol nickel nitrate, 0.1 mmol cobalt nitrate, 0.1 mmol ferric chloride, and 0.1 mmol ammonium metavanadate were respectively weighed and dissolved in 30 mL deionized water. After stirring for 20 minutes, 5 mmol L-cysteine was added and stirring was continued for 10 minutes to obtain a mixed solution.
[0033] (4) The mixed solution of step (2) was transferred to a 50 mL reactor, and the carbon cloth obtained after the treatment of step (1) was added. The reactor was sealed and transferred to a forced air drying oven. The temperature was raised to 160°C at a rate of 2°C / min, and then the reaction was kept at this temperature for 10 hours, and then the temperature was lowered to room temperature at a rate of 2°C / min.
[0034] (5) The carbon cloth after the reaction in step (4) was ultrasonically cleaned with deionized water and anhydrous ethanol for 30 seconds, and then dried at 80°C to obtain an integrated electrode CC@Sn 0.5 (MoFeCoNiV) 0.5 S2.
[0035] The integrated CC@Sn obtained by the present invention 1-x (MoFeCoNiV) x When S2 material is used as negative electrode material for lithium-ion batteries, no conductive agent or binder is required. 1-x (MoFeCoNiV) x The S material was cut into electrode sheets of 1 cm × 1 cm in size and used directly as electrodes. Each small piece of carbon cloth was weighed before assembling the battery in order to calculate the mass of the attached active material. In a glove box filled with argon atmosphere, 1 mol / L LiPF6 was used as the electrolyte (the volume ratio of ethylene carbonate: diethyl carbonate: dimethyl carbonate was 1:1:1), Celgard 2400 microporous polypropylene was used as the battery separator, and pure metal lithium sheets were used as the battery electrodes to assemble the battery for testing.
Claims
1. A high initial efficiency tin disulfide-based integrated electrode, characterized in that: (1) The specific composition of the tin disulfide-based active material is Sn 1-x (MoFeCoNiV) x S2; (2) The conductive substrate of the integrated electrode is commercial carbon cloth; (3) The method for preparing the integrated electrode is the hydrothermal method.
2. A method for preparing a tin disulfide-based integrated electrode as claimed in claim 1, characterized in that: The specific steps are as follows: (1) The commercial carbon cloth was cut into suitable small pieces, and the carbon cloth was ultrasonically cleaned in dilute nitric acid, and then ultrasonically cleaned with deionized water and anhydrous ethanol respectively, and then dried for the next experiment; (2) Weigh the corresponding metal salts of Sn, Mo, Fe, Co, Ni and V according to the ratio in the molecular formula and dissolve them in deionized water. After stirring and dissolving, add L-cysteine and continue stirring to obtain a mixed solution. (4) transferring the mixed solution of step (2) into a reaction kettle, adding the carbon cloth obtained after the treatment of step (1), sealing the reaction kettle, transferring it to a forced air drying oven, heating it to 160-180° C., and then reacting at a constant temperature for 6-10 hours, and then cooling it to room temperature; (5) The carbon cloth after the reaction in step (4) is ultrasonically cleaned with deionized water and anhydrous ethanol, and then dried to obtain an integrated electrode CC@Sn 1-x (MoFeCoNiV) x S2.
3. The tin disulfide-based integrated electrode according to claim 1, characterized in that: The integrated electrode does not require the addition of adhesives and conductive agents and can be directly used as the negative electrode material of lithium-ion batteries, and exhibits the characteristics of high initial efficiency and high reversible capacity.