Preparation method of high-specific-capacity lithium battery positive electrode material
阅读说明：本技术 一种高比容量的锂电池正极材料的制备方法 (Preparation method of high-specific-capacity lithium battery positive electrode material ) 是由 叶建荣 于 2020-12-12 设计创作，主要内容包括：本发明涉及锂电池正极材料制备技术领域,公开了一种高比容量的锂电池正极材料的制备方法,通过对硫碳复合材料性能以及充放电机理的研究,不仅解决现有技术中,含硫复合材料达不到快速充放电的要求,需要大量辅助导电剂的添加,放电时易溶解在电解质液中,影响电池使用寿命等问题,显著提升含硫复合材料在锂电池中发挥的特性,能够有效增正极材料的性能,制备得到的正极材料性能得到全面提升,循环性增强。本发明提高了硫碳复合正极材料的导电能力,比容量高,有效值达到1240-1300mAh/g,在室温下也能够表现出极好的循环性能,对锂电池快速充放电、放电时间长、质轻等性能得到进一步提高,满足现代电子设备行业的需求,减少了导电剂的使用量,降低了成本。(The invention relates to the technical field of preparation of lithium battery anode materials, and discloses a preparation method of a high-specific-capacity lithium battery anode material. The invention improves the conductive capacity of the sulfur-carbon composite anode material, has high specific capacity, has an effective value of 1240-1300mAh/g, can show excellent cycle performance at room temperature, further improves the performances of quick charge and discharge, long discharge time, light weight and the like of a lithium battery, meets the requirements of the modern electronic equipment industry, reduces the using amount of a conductive agent and reduces the cost.)
1. A preparation method of a lithium battery anode material with high specific capacity is characterized by comprising the following steps:
(1) putting 15-16 g europium nitrate into a beaker, adding 90-100 ml sodium carbonate aqueous solution into the beaker, starting a stirrer to stir for 30-40 minutes, dropwise adding ammonia water solution with the pH value of 11.2-11.3 into the beaker until the precipitation amount is not changed, carrying out precipitation filtration, washing for 5-8 times by using deionized water, then putting the precipitate into a crucible, drying for 3-4 hours in a vacuum drying box at 90-100 ℃, finally putting the crucible into a muffle furnace, heating to 800-, transferring the ultrasonic mixture into a high-temperature high-pressure reaction kettle, setting the temperature at 170-180 ℃, the reaction pressure at 1.35-1.45MPa, the reaction time at 12-14 hours, naturally cooling to 15-20 ℃, carrying out centrifugal washing for 3-4 times by using deionized water, then placing the mixture into an oven at 70-80 ℃ for drying for 12-15 hours, and grinding the mixture into powder to obtain the nano composite active material;
(2) adding 120 ml of 110 plus deionized water and 0.15-0.16 g of polyvinyl alcohol into a four-neck flask provided with a stirrer, a condenser and a thermometer, stirring and dissolving, heating to 63-65 ℃, then sequentially adding 5.6-5.7 ml of dimethylformamide, 23-24 g of acrylonitrile monomer and 9.3-9.5 g of elemental sulfur, introducing nitrogen, stirring and reacting, adding 0.31-0.33 g of azobisisobutyronitrile at 180 revolutions per minute, preserving heat and reacting for 3.5-4.0 hours at 58-60 ℃, filtering after the reaction is finished, washing for 4-5 times by using deionized water, drying for 6-8 hours at 55-60 ℃, then placing in a crucible for grinding for 1.5-2.0 hours, adding the active material prepared in the step (1) into the ground fine powder, continuously mixing and grinding for 0.5-1.0 hour, placing the anode material in a tubular furnace, introducing nitrogen for protection, uniformly heating to 300-310 ℃ within 90-100 minutes, keeping the temperature and heating for 2.5-3.0 hours, and cooling to room temperature at the speed of 3-4 ℃/minute to obtain the product, namely the anode material.
2. The method for preparing the lithium battery cathode material with high specific capacity as claimed in claim 1, wherein the mass concentration of the sodium carbonate aqueous solution in the step (1) is 0.37-0.40%.
3. The method for preparing a lithium battery cathode material with high specific capacity as claimed in claim 1, wherein the molar concentration of the acetic acid solution in the step (1) is 0.65-0.68 mol/l.
4. The method for preparing a high specific capacity lithium battery cathode material as claimed in claim 1, wherein the particle size of the nanocomposite active material in the step (1) is between 15 and 35 nm, and the morphology is granular.
5. The method for preparing a high-specific-capacity lithium battery positive electrode material as claimed in claim 1, wherein the active material is added in an amount of 0.23-0.25% by mass of the fine powder in the step (2).
Technical Field
The invention belongs to the technical field of preparation of lithium battery anode materials, and particularly relates to a preparation method of a lithium battery anode material with high specific capacity.
Background
A "lithium battery" is a type of battery using a nonaqueous electrolyte solution with lithium metal or a lithium alloy as a negative electrode material. Lithium metal batteries were first proposed and studied by Gilbert n. Lewis in 1912. In the 70 s of the 20 th century, m.s. Whittingham proposed and began to study lithium ion batteries. Because the chemical characteristics of lithium metal are very active, the requirements on the environment for processing, storing and using the lithium metal are very high. With the development of scientific technology, lithium batteries have become the mainstream.
The prior lithium secondary battery anode material is commonly used with transition metal oxide and sulfide; studies have also reached a more mature level. The effective charge-discharge capacity is stabilized in the range of 120-200mAh/g, and a better improved treatment method cannot be obtained. The publication number is CN110828784A, and discloses a lithium battery positive electrode material, a preparation method and an application thereof, the related positive electrode material is a transition metal oxide with a layered structure, which improves the first discharge specific capacity of the battery to a certain extent, but the transition metal oxide can generate structural change in the charging and discharging process, which causes continuous loss of electric quantity, low effective charging and discharging capacity, and poor cycle characteristics, and has the disadvantages of high price, large pollution and the like.
Currently, research on the performance of lithium batteries is being fully opened, and the disadvantages of conventional transition metal oxides as positive electrode materials are gradually exposed. In the research of lithium batteries, the report of the high-specific-capacity positive electrode material is generally accompanied by great defects, so that the application value is limited. At present, no good method for solving the problem exists, so that the field of lithium battery performance research is not brought into full play. Due to the bottleneck problems, the lithium battery has a great application prospect in the development of electronic products, and is a trend for promoting the development of novel high specific energy battery technology.
Disclosure of Invention
The sulfur-containing composite material becomes a new generation of anode material, can form a plurality of new electrochemical systems by matching with a lithium cathode, has small electrochemical equivalent and large theoretical specific capacity, but has a plurality of problems to reach the practical application level, such as slow reaction speed at normal temperature, incapability of meeting the requirement of quick charge and discharge, need of adding a large amount of auxiliary conductive agents, easy dissolution in electrolyte liquid during discharge, influence on the service life of the battery and the like.
The invention aims to provide a preparation method of a lithium battery anode material with high specific capacity, which aims to solve the existing problems, improve the conductivity of a sulfur-carbon composite material, promote the performance of the high specific capacity of the lithium battery anode material, and ensure the cycle performance and the environmental protection performance of the lithium battery.
The invention is realized by the following technical scheme:
a preparation method of a lithium battery anode material with high specific capacity comprises the following main technical means: the prepared active agent is utilized to excite the conductivity of the sulfur-containing composite material, so that the obtained positive electrode material is high in charging and discharging efficiency and good in safety performance, the cyclic charging and discharging performance is guaranteed, the performance of the sulfur-containing composite material in a lithium battery is remarkably improved, and the charging and discharging cyclic performance of the positive electrode material can be effectively enhanced;
specifically, the preparation of the sulfur-carbon composite anode material comprises the following process steps:
adding 120 ml of 110 plus deionized water and 0.15-0.16 g of polyvinyl alcohol into a four-neck flask provided with a stirrer, a condenser tube and a thermometer, stirring and dissolving, heating to 63-65 ℃, then sequentially adding 5.6-5.7 ml of dimethylformamide, 23-24 g of acrylonitrile monomer and 9.3-9.5 g of elemental sulfur, introducing nitrogen, stirring and reacting, adding 0.31-0.33 g of azobisisobutyronitrile at 180 revolutions per minute, preserving heat and reacting for 3.5-4.0 hours at 58-60 ℃, filtering after the reaction is finished, washing for 4-5 times by using deionized water, drying for 6-8 hours at 55-60 ℃, then placing in a crucible for grinding for 1.5-2.0 hours, adding 0.23-0.25 mass percent of active material into the ground fine powder, continuously mixing and grinding for 0.5-1.0 hour, placing the anode material in a tubular furnace, introducing nitrogen for protection, uniformly heating to 300-310 ℃ within 90-100 minutes, keeping the temperature and heating for 2.5-3.0 hours, and cooling to room temperature at the speed of 3-4 ℃/minute to obtain the product, namely the anode material.
The preparation method of the active material comprises the following steps: putting 15-16 g europium nitrate into a beaker, adding 90-100 ml sodium carbonate aqueous solution with the mass concentration of 0.37-0.40% into the beaker, starting a stirrer to continuously stir for 30-40 minutes, dropwise adding ammonia aqueous solution with the pH value of 11.2-11.3 into the beaker until the precipitation amount is not changed, carrying out precipitation filtration, washing for 5-8 times by using deionized water, then putting the precipitate into a crucible, drying in a vacuum drying box at 90-100 ℃ for 3-4 hours, finally putting the crucible into a muffle furnace, heating to 800-class 820 ℃ for calcination, naturally cooling to room temperature along with the furnace, then adding 155-165 ml acetic acid solution with the molar concentration of 0.65-0.68 mol/L, simultaneously adding 29-33 g newly prepared ferric hydroxide colloid, stirring for 30-60 minutes at the speed of 300-class 400 r/min, ultrasonic treatment is carried out for 15-20 minutes under the power of 120 watts at 100 plus temperature, the ultrasonic mixture is transferred into a high-temperature high-pressure reaction kettle, the set temperature is 180 plus temperature, the reaction pressure is 1.35-1.45MPa, the reaction time is 12-14 hours, the mixture is naturally cooled to 15-20 ℃, deionized water is used for centrifugal washing for 3-4 times, then the mixture is placed into a drying oven at 70-80 ℃ for drying for 12-15 hours, and the mixture is ground into powder. The particle size of the nano composite active material is between 15 and 35 nanometers, and the shape is granular.
The prepared active material and the sulfur-containing compound are calcined together to form a polymer network structure, the network structure is rich in interweaving, the crystal form of the nano structure hinders the dissolution loss of the active material, the surface area is increased, the actual area of electrode reaction is increased, the dynamic behavior of electrochemical reaction is improved, and the stress caused by volume change caused by the insertion and the separation of lithium ions is avoided, so that the cycle performance is improved, the conductivity of the anode material can be excited, the high-specific-capacity anode material is prepared, and the cycle charge-discharge performance of the lithium battery is improved.
After the positive electrode material is obtained by adopting the scheme, an electrode is further prepared;
after optimization, preparing the electrode plate by adopting a coating method, wherein the electrode plate comprises the following components in parts by weight: 160 parts of anode material 140, 10-15 parts of conductive agent and 15-18 parts of binder. The conductive agent is acetylene black; the binder is polyethylene oxide.
The preparation method comprises the following steps: mixing the preparation materials according to the weight ratio, grinding the mixture evenly in a ball mill, mixing the mixture into paste by using a mixed solvent, evenly coating the paste on a current collector, drying the paste for 22 to 24 hours at the temperature of between 20 and 25 ℃, cutting the paste into pole pieces with the square centimeter of 1 multiplied by 1, and drying the pole pieces for 10 to 12 hours in a vacuum drying oven at the temperature of between 60 and 65 ℃.
Assembling the lithium battery:
preferably, a lithium sheet is taken as a negative electrode, a diaphragm is PVDF-HFP, and LiPF6/EC-DMC-EMC (1:1:1) with the molar concentration of 1mol/L is taken as electrolyte; the simulated cells were assembled in a glove box under argon atmosphere and the assembled cell samples were tested.
After the lithium battery is assembled, a charge-discharge tester is adopted to test the charge-discharge performance at 25 ℃, the charge-discharge current density is 0.6mA.cm < 2 >, and the test voltage range is 1.8-3.0V.
The invention fully exerts the high specific capacity value of the sulfur-containing composite material, improves the performance of the sulfur-carbon composite anode material in preparation and use, improves the conductivity of the material, and the conductivity of the prepared anode material reaches 1.2-3.0 multiplied by 10- 6S/cm. The specific capacity is high, the effective value reaches 1240-1300mAh/g, excellent cycle performance can be shown at room temperature, and the specific capacity of more than 950mAh/g can be obtained after the cycle number reaches 100 times. The problem that the specific capacity and the cycle performance of the lithium battery cannot be achieved is solved, the performances of quick charge and discharge, long discharge time, light weight and the like of the lithium battery are further improved, and the requirements of the modern electronic equipment industry are met.
Compared with the prior art, the invention has the following advantages: in order to solve the problems of large electric quantity loss, low cyclic utilization rate and the like caused by the defects of a lithium battery anode material, the invention provides a preparation method of a lithium battery anode material with high specific capacity, through the research on the performance of a sulfur-carbon composite material and a charge-discharge mechanism, the invention not only solves the problems that in the prior art, the theoretical specific capacity of a sulfur-containing composite material is large, but the reaction speed is low at normal temperature, the requirement of quick charge-discharge cannot be met, a large amount of auxiliary conductive agents are required to be added, the sulfur-containing composite material is easy to dissolve in electrolyte liquid during discharge, the service life of the battery is influenced, and the like, obviously improves the characteristics of the sulfur-containing composite material exerted in the lithium battery, can effectively increase the performance of the anode material, and can well solve the defect that the capacity loss of the existing sulfur-containing anode materialThe performance of the electrode material is comprehensively improved, and the cyclicity is enhanced. The invention fully exerts the high specific capacity value of the sulfur-containing composite material, improves the performance of the sulfur-carbon composite anode material in preparation and use, improves the conductivity of the material, and the conductivity of the prepared anode material reaches 1.2-3.0 multiplied by 10-6S/cm. The specific capacity is high, the effective value reaches 1240-1300mAh/g, excellent cycle performance can be shown at room temperature, and the specific capacity can exceed 950mAh/g after the cycle number reaches 100 times. The invention solves the problem that the specific capacity and the cycle performance of the lithium battery can not be compatible, the performances of quick charge and discharge, long discharge time, light weight and the like of the lithium battery are further improved, the requirements of the modern electronic equipment industry are met, the use amount of a conductive agent is reduced, and the cost is reduced, the invention effectively solves the problems that the specific capacity of a sulfur-containing compound is high, the sulfur-containing compound is easy to dissolve, the self-discharge phenomenon is serious, and the cycle service life can not be prolonged, so that the charge cycle service life is greatly prolonged under the condition of ensuring the high specific capacity performance of a sulfur-containing anode material, has the characteristics of low cost, no pollution and high capacity, greatly reduces the preparation cost, can realize the practical significance of improving the application of the sulfur-containing compound represented by a sulfur-carbon composite material in the lithium battery industry and improving the market competitiveness, and has higher value for the utilization of, the method obviously promotes the diversified and rapid development and the sustainable development of the lithium battery anode material, and is a technical scheme which is very worthy of popularization and application.
Detailed Description
In order to make the objects, technical solutions and effects of the present invention clearer and clearer, the present invention is further described with reference to specific embodiments, and it should be understood that the specific embodiments described herein are only used for explaining the present invention and are not used for limiting the technical solutions provided by the present invention.
Example 1
The preparation method of the sulfur-carbon composite anode material comprises the following process steps:
adding 110 ml of deionized water and 0.15 g of polyvinyl alcohol into a four-mouth flask provided with a stirrer, a condenser tube and a thermometer, stirring for dissolving, heating to 63 ℃, then sequentially adding 5.6 ml of dimethylformamide, 23 g of acrylonitrile monomer and 9.3 g of elemental sulfur, introducing nitrogen, stirring for reaction, adding 0.31 g of azodiisobutyronitrile at 180 r/min, reacting for 3.5 hours at 58 ℃, filtering after the reaction is finished, washing for 4 times by using deionized water, drying at 55 deg.C for 6 hr, grinding in crucible for 1.5 hr, adding 0.23 wt% of active material into the ground fine powder, mixing and grinding for 0.5 hr, placing in a tube furnace, introducing nitrogen gas for protection, uniformly heating to 300 ℃ within 90 minutes, keeping the temperature, heating for 2.5 hours, and cooling to room temperature at the speed of 3 ℃/minute to obtain the product, namely the cathode material.
The preparation method of the active material comprises the following steps: putting 15 g of europium nitrate in a beaker, adding 90 ml of 0.37 mass percent aqueous solution of sodium carbonate into the beaker, starting a stirrer to stir for 30 minutes continuously, dropwise adding aqueous solution of ammonia with the pH value of 11.2 into the beaker until the precipitation amount is not changed, carrying out precipitation filtration, washing for 5 times by using deionized water, then putting the precipitate in a crucible, drying for 3 hours in a 90 ℃ vacuum drying box, finally putting the crucible in a muffle furnace, heating to 800 ℃ for calcination, wherein the calcination time is 2 hours, naturally cooling to room temperature along with the furnace, then adding the precipitate in 155 ml of 0.65 mol/L acetic acid solution, simultaneously adding 29 g of newly prepared ferric hydroxide colloid, stirring for 30 minutes at the speed of 300 revolutions/minute, carrying out ultrasonic treatment for 15 minutes at the power of 100 watts, transferring the ultrasonic mixture into a high-temperature high-pressure reaction kettle, setting the temperature to 170 ℃, the reaction pressure is 1.35MPa, the reaction time is 12 hours, the reaction is naturally cooled to 15 ℃, deionized water is used for centrifugal washing for 3 times, the reaction product is dried in an oven at 70 ℃ for 12 hours, and the reaction product is ground into powder. The particle size of the nano composite active material is between 15 and 35 nanometers, and the shape is granular.
Example 2
The preparation method of the sulfur-carbon composite anode material comprises the following process steps:
115 ml of deionized water and 0.155 g of polyvinyl alcohol are added into a four-mouth flask provided with a stirrer, a condenser tube and a thermometer, stirred and dissolved, the temperature is raised to 64 ℃, then sequentially adding 5.65 ml of dimethylformamide, 23.5 g of acrylonitrile monomer and 9.4 g of elemental sulfur, introducing nitrogen, stirring for reaction, adding 0.32 g of azobisisobutyronitrile at 190 r/min, reacting for 3.8 hours at 59 ℃, filtering after the reaction is finished, washing for 4 times by using deionized water, drying at 58 deg.C for 7 hr, grinding in crucible for 1.8 hr, adding 0.24 wt% of active material into the ground fine powder, mixing and grinding for 0.8 hr, placing in tube furnace, introducing nitrogen gas for protection, uniformly heating to 305 ℃ within 95 minutes, keeping the temperature, heating for 2.8 hours, and cooling to room temperature at the speed of 3.5 ℃/minute to obtain the product, namely the cathode material.
The preparation method of the active material comprises the following steps: putting 15.5 g of europium nitrate into a beaker, adding 95 ml of sodium carbonate aqueous solution with the mass concentration of 0.38 percent into the beaker, starting a stirrer to stir continuously for 35 minutes, dropwise adding ammonia aqueous solution with the pH value of 11.25 into the beaker until the precipitation amount is not changed, carrying out precipitation filtration, washing for 6 times by using deionized water, then putting the precipitate into a crucible, drying for 3.5 hours in a 95 ℃ vacuum drying box, finally putting the crucible into a muffle furnace, heating to 810 ℃ to calcine for 2.5 hours, naturally cooling to room temperature along with the furnace, then adding the precipitate into 160 ml of acetic acid solution with the molar concentration of 0.66 mol/L, simultaneously adding 31 g of newly prepared ferric hydroxide colloid, stirring for 45 minutes at the speed of 350 rpm, carrying out ultrasonic treatment for 18 minutes at the power of 110 watts, transferring the ultrasonic mixture into a high-temperature high-pressure reaction kettle, setting the temperature to 175 ℃, the reaction pressure is 1.40MPa, the reaction time is 13 hours, the reaction solution is naturally cooled to 18 ℃, deionized water is used for centrifugal washing for 3 times, the reaction solution is placed in a 75 ℃ oven for drying for 13 hours, and the reaction solution is ground into powder. The particle size of the nano composite active material is between 15 and 35 nanometers, and the shape is granular.
Example 3
The preparation method of the sulfur-carbon composite anode material comprises the following process steps:
adding 120 ml of deionized water and 0.16 g of polyvinyl alcohol into a four-mouth flask provided with a stirrer, a condenser tube and a thermometer, stirring for dissolving, heating to 65 ℃, then sequentially adding 5.7 ml of dimethylformamide, 24 g of acrylonitrile monomer and 9.5 g of elemental sulfur, introducing nitrogen, stirring for reaction, adding 0.33 g of azodiisobutyronitrile at 200 r/min, reacting for 4.0 hours at 60 ℃, filtering after the reaction is finished, washing for 5 times by using deionized water, drying at 60 deg.C for 8 hr, grinding in crucible for 2.0 hr, adding 0.25 wt% of active material into the ground fine powder, mixing and grinding for 1.0 hr, placing in tubular furnace, introducing nitrogen gas for protection, uniformly heating to 310 ℃ within 100 minutes, keeping the temperature, heating for 3.0 hours, and cooling to room temperature at the speed of 4 ℃/minute to obtain the product, namely the cathode material.
The preparation method of the active material comprises the following steps: putting 16 g of europium nitrate in a beaker, adding 100 ml of sodium carbonate aqueous solution with the mass concentration of 0.40% into the beaker, starting a stirrer to stir continuously for 40 minutes, dropwise adding ammonia water solution with the pH value of 11.3 into the beaker until the precipitation amount is not changed, carrying out precipitation filtration, washing 8 times by using deionized water, then putting the precipitate in a crucible, drying for 4 hours in a 100 ℃ vacuum drying box, finally putting the crucible in a muffle furnace, heating to 820 ℃ for calcination, wherein the calcination time is 3 hours, naturally cooling to room temperature along with the furnace, then adding the precipitate in 165 ml of acetic acid solution with the molar concentration of 0.68 mol/L, simultaneously adding 33 g of newly prepared ferric hydroxide colloid, stirring for 60 minutes at the speed of 400 rpm, carrying out ultrasonic treatment for 20 minutes at the power of 120 watts, transferring the ultrasonic mixture into a high-temperature high-pressure reaction kettle, setting the temperature to 180 ℃, the reaction pressure is 1.45MPa, the reaction time is 14 hours, the reaction solution is naturally cooled to 20 ℃, deionized water is used for centrifugal washing for 4 times, the reaction solution is placed in an oven at 80 ℃ for drying for 15 hours, and the reaction solution is ground into powder. The particle size of the nano composite active material is between 15 and 35 nanometers, and the shape is granular.
Example 4
The only difference from example 3 is that the active material was prepared by the following method: putting 15.5 g of europium nitrate into a beaker, adding 95 ml of 0.38% sodium carbonate aqueous solution into the beaker, starting a stirrer to stir for 35 minutes continuously, dropwise adding 11.25 pH ammonia aqueous solution into the beaker until the precipitation amount is not changed, carrying out precipitation filtration, washing for 6 times by using deionized water, then putting the precipitate into a crucible, drying for 3.5 hours in a 95 ℃ vacuum drying oven, finally putting into a muffle furnace, heating to 810 ℃ for calcination, wherein the calcination time is 2.5 hours, and naturally cooling to room temperature along with the furnace to grind into powder. The rest remained unchanged.
Example 5
The only difference from example 3 is that the active material was prepared by the following method: adding 31 g of newly prepared ferric hydroxide colloid into 140 ml of acetic acid solution with the molar concentration of 0.66 mol/L, stirring at the speed of 350 r/min for 45 min, carrying out ultrasonic treatment at the power of 110W for 18 min, transferring the ultrasonic mixture into a high-temperature high-pressure reaction kettle, setting the temperature at 175 ℃, the reaction pressure at 1.40MPa and the reaction time at 13 h, naturally cooling to 18 ℃, carrying out centrifugal washing for 3 times by using deionized water, drying in a 75 ℃ oven for 13 h, and grinding into powder. The rest remained unchanged.
After the positive electrode material is obtained by adopting the scheme, an electrode is further prepared;
after optimization, preparing the electrode plate by adopting a coating method, wherein the electrode plate comprises the following components in parts by weight: 150 parts of positive electrode material, 12 parts of conductive agent and 16 parts of binder. The conductive agent is acetylene black; the binder is polyethylene oxide.
The preparation method comprises the following steps: mixing the preparation materials according to the weight ratio, grinding the mixture evenly in a ball mill, mixing the mixture into paste by using a mixed solvent, evenly coating the paste on a current collector, drying the paste for 23 hours at the temperature of 22 ℃, cutting the paste into pole pieces with the square centimeter of 1 multiplied by 1, and drying the pole pieces for 11 hours in a vacuum drying oven at the temperature of 62 ℃.
Assembling the lithium battery:
preferably, a lithium sheet is taken as a negative electrode, a diaphragm is PVDF-HFP, and LiPF6/EC-DMC-EMC (1:1:1) with the molar concentration of 1mol/L is taken as electrolyte; the simulated cells were assembled in a glove box under argon atmosphere and the assembled cell samples were tested.
Comparative example 1
Instead of half the amount of active material in example 3, molecular sieves with an average pore size between 10-20nm were used, the rest remaining unchanged.
Comparative example 2
Instead of the entire amount of active material in example 3, a molecular sieve with an average pore diameter between 10 and 20nm was used, the rest remaining unchanged.
First, performance experiment
The method of the embodiment 1-5 and the method of the comparative example 1-2 are used for preparing the lithium battery assembly sample, the control group is a positive plate prepared by processing the lithium battery elemental sulfur-carbon composite positive material produced by a combined fertilizer certain nanotechnology development limited company, and the battery is assembled by the same method; after the lithium batteries prepared in each group are assembled, a charge-discharge tester is adopted to carry out charge-discharge performance test at 25 ℃, the charge-discharge current density is 0.6mA.cm2, and the test voltage range is 1.8-3.0V. Keeping the independent variables consistent in the test, performing result statistical analysis (designing the test by statistical method before the test, then performing the test, recording the test data, analyzing to obtain the test result, and fully using the statistical tool to explain the result to the maximum extent in the process)
Secondly, the experimental result is as follows: in the embodiments 1-5, the first discharge specific capacity reaches 1257 mAh/g, 1300mAh/g, 1273 mAh/g, 1004 mAh/g and 971 mAh/g in sequence; after the cycle times reach 120 times, the specific capacity sequentially reaches 1015mAh/g, 1122 mAh/g, 1060 mAh/g, 667 mAh/g and 604 mAh/g; comparative example 1 the first discharge specific capacity was 895 mAh/g; the specific capacity is only 493mAh/g after the cycle times reach 120 times; comparative example 2 the first discharge specific capacity was 730 mAh/g; the specific capacity is only 358mAh/g after the cycle times reach 120 times; the first discharge specific capacity of the control group is 625 mAh/g; the specific capacity is 300mAh/g after the cycle times reach 120 times; therefore, the positive electrode material prepared by the method has higher specific capacity and shows excellent cycle performance.
The invention effectively solves the problems that the specific capacity of the sulfur-containing compound is high, the sulfur-containing compound is easy to dissolve, the self-discharge phenomenon is serious, and the cycle service life cannot be improved, so that the charging cycle service life is greatly improved under the condition of ensuring the high specific capacity performance of the sulfur-containing anode material, the invention has the characteristics of low cost, no pollution and high capacity, the preparation cost is greatly reduced, the practical significance of improving the application of the sulfur-containing compound represented by the sulfur-carbon composite material in the lithium battery industry and improving the market competitiveness can be realized, the invention has higher value for the utilization of the high specific capacity material and the research of a novel lithium battery, the diversification, the rapid development and the sustainable development of the lithium battery anode material can be obviously promoted, and the invention is a technical scheme which.