CN114583146A - Preparation method of sodium-sulfur battery positive electrode material - Google Patents
Preparation method of sodium-sulfur battery positive electrode material Download PDFInfo
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Abstract
The invention provides a preparation method of a sodium-sulfur battery positive electrode material, which comprises the steps of pretreating tea seed cake, and then adding NaOH and Na2SO3Soaking the tea leaves in the boiling mixed solution for 3-12 h, centrifugally collecting precipitate after the product is cooled, washing by using boiling deionized water, and freeze-drying to obtain lignin-removed tea leaf powder; grinding and drying the lignin-removed tea residue powder and KOH in an absolute ethanol solvent, calcining for 1-3 h at the temperature of 600-1000 ℃ in inert gas, washing and drying the calcined product by using an HCl solution; mixing the activated tea residue powder and solid sublimed sulfur according to the mass ratio of 1: 1-2, reacting for 10-15 h at the temperature of 140-160 ℃, heating to 180-300 ℃ to remove surface sulfur, and obtaining the sodium-sulfur battery anode material. The positive electrode material of the sodium-sulfur battery prepared by the invention can be improvedSpecific capacity of sodium-sulfur battery.
Description
Technical Field
The invention relates to the technical field of sodium-sulfur batteries, in particular to a preparation method of a sodium-sulfur battery positive electrode material.
Background
Energy shortage and environment in the worldThe contamination is increasingly aggravated, and the development of a secondary battery system having a high specific capacity is imminent. The room temperature sodium-sulfur battery has higher theoretical specific capacity as a novel secondary battery. However, the conductivity of sulfur is very poor (about 5X 10)-30 S·m-1) And the polysulfide has strong shuttling effect and the like, so that the specific capacity of the room-temperature sodium-sulfur battery anode material is difficult to improve.
Aiming at the problem that the specific capacity of the positive electrode material of the sodium-sulfur battery is low at present, the search for a replaceable high-sulfur-content high-capacity green environment-friendly positive electrode material of the sodium-sulfur battery is not slow.
Disclosure of Invention
In order to solve the technical problems in the prior art, the invention provides a preparation method of a sodium-sulfur battery positive electrode material. Because China is a large tea-producing country, a large amount of tea seed cake waste generated in the tea making process contains abundant C, N and other elements, the invention uses the biomass charcoal derived from the tea seed cake waste as the positive electrode material of the sodium-sulfur battery, which not only can solve the problem of low specific capacity of the positive electrode material of the sodium-sulfur battery at present, but also can greatly reduce the waste problem of a large amount of tea seed cake waste, and realize waste utilization, environmental protection and energy conservation.
In order to achieve the purpose, the invention provides a preparation method of a sodium-sulfur battery positive electrode material, which comprises the following steps:
step one, tea seed cake is pretreated to obtain tea seed cake powder;
step two, adding the tea residue powder prepared in the step one into NaOH and Na2SO3Soaking the tea leaves in the boiling mixed solution for 3-12 h, centrifugally collecting precipitate after the product is cooled, washing by using boiling deionized water, and freeze-drying to obtain lignin-removed tea leaf powder;
step three, grinding and drying the lignin-removed tea residue powder prepared in the step two and KOH in an absolute ethyl alcohol solvent, calcining for 1-3 h in inert gas at the temperature of 600-; wherein the mass ratio of the lignin-removed tea residue powder to KOH is 1: 0.1 to 5;
step four, mixing the activated tea residue powder and the solid sublimed sulfur according to the mass ratio of 1: 1-2, uniformly mixing, reacting for 10-15 h at the temperature of 140-160 ℃, heating to the temperature of 180-300 ℃ to remove surface sulfur, and obtaining the sodium-sulfur battery anode material.
Further, in the step one, the tea seed cake is pretreated, specifically: crushing the tea seed cake by a crusher, then carrying out ball milling for 1-2 h, and sieving the ball-milled tea residue powder by a sieve of 80-150 meshes.
Further, in the second step, each gram of tea residue powder is dispersed in 0.04-0.1L of NaOH and Na2SO3In the boiling mixed solution of (1); NaOH and Na2SO3NaOH and Na in the boiling mixed solution of (2)2SO3The concentration ratio of (A) to (B) is 4-7: 1.
further, in step three, the concentration of the HCl solution is 1M.
Further, in the third step, the inert gas is nitrogen or argon with the purity of 99.999%.
Further, in step three, the calcination process is performed in a tube furnace.
The invention has the following beneficial effects:
1. the invention provides a preparation method of a sodium-sulfur battery anode material, which comprises the steps of firstly, pre-treating tea seed meal in NaOH and Na2SO3Soaking the mixture in the boiling mixed solution for 3-12 h to carry out delignification treatment, then mixing the tea residue powder subjected to the delignification treatment with KOH to carry out activation treatment, and finally mixing the tea residue powder subjected to the activation treatment with solid sublimed sulfur to obtain the sodium-sulfur battery anode material. The method combines the two steps of delignification treatment and KOH activation to show visible superiority, the delignification process can effectively loosen the structure of the bulk tea seed cake, increase the subsequent contact area with KOH, and ensure that the KOH activation is more uniform. Meanwhile, in the delignification process, mesoporous pores appear on plant cell walls along with the swelling of biomass, and when KOH is activated, KOH and the biomass react as follows: 6KOH + 2C → 2K + 3H2 +2K2CO3. Pickling with HCl solution produces numerous micropores which are connected to one another or previously formedThe connection of partial mesopores forms new mesopores and macropores, and the existence of a hierarchical pore structure improves the accessibility of the electrolyte. The invention uses NaOH and Na2SO3The boiling mixed solution is used for removing lignin from the tea residue powder, so that the hardness of the tea residue can be reduced, and the subsequent uniform mixing with KOH is facilitated. By using KOH for activation treatment, on one hand, the holes can be formed on the biomass charcoal, and simultaneously, the conductivity of the charcoal material can be improved. Mixed with sublimed sulfur, and mainly loads S in a carbon material carrier. The finally prepared sodium-sulfur battery positive electrode material has a biomass derived carbon host with high specific surface area, high micropore volume and a hierarchical pore structure, and can still maintain good electrochemical performance on the premise of higher sulfur loading.
2. The invention provides a preparation method of a sodium-sulfur battery anode material, which uses NaOH and Na2SO3The time for removing the lignin from the tea residue powder by the boiling mixed solution is very critical. When the time of delignification treatment is too low, the first discharge specific capacity and the 100-time discharge specific capacity are seriously reduced, and the content of micropores is reduced after subsequent KOH activation and small sulfur molecules (S) are reduced mainly because the degree of delignification is not thorough and a large number of massive biomasses still exist2-4) Confinement within the micropores. When the delignification treatment time is too long, the delignification treatment time reaches the limit, and the delignification treatment time is too long, so that resources are wasted, and the efficiency is reduced.
In addition, the amount of KOH used is also important when the tea grounds after delignification treatment are subjected to activation treatment. When the using amount of KOH is too small, the activation degree of the biomass is not complete enough, a small specific surface area and a small micropore volume are presented, and the pore-forming effect is not obvious; when the amount is too large, part of the structure is broken, so that the active material is lost, and the shuttle of polysulfide cannot be effectively limited. The ratio of activated dry powder to S is also important, too high a ratio will increase surface S, resulting in too rapid a capacity fade; too little will reduce the S load, not beneficial to practical production application. The tea residue biomass charcoal calcined at high temperature in the invention has good conductivity as a sulfur carrier and passes through micropores (only can contain S)2-4) Greatly reducing solubilityThe formation of a cyclic polysulfide effectively limits polysulfide shuttling.
3. The invention provides a preparation method of a sodium-sulfur battery anode material, which is characterized in that biomass charcoal after delignification and KOH activation has a good pore structure and can enable S to be in a good pore structure8The molecule is present as S during the subsequent cycles2-4The sodium-sulfur battery can avoid the generation of soluble polysulfide, thereby improving the specific capacity of the sodium-sulfur battery. The invention uses a two-step method of delignification and KOH activation to realize the construction of a high specific surface area and a hierarchical porous structure, focuses on 0.6 nm micropores to ensure that the existence form of sulfur is small sulfur molecules, and greatly avoids the shuttle of polysulfide. The biomass charcoal after delignification and KOH activation has rich mesopores and macropores, which is beneficial to the load of high-content sulfur and the accessibility of electrolyte, thereby improving the electrochemical performance of the biomass charcoal.
In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below with reference to the drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:
fig. 1 is a thermogravimetric analysis diagram of a positive electrode material of a sodium-sulfur battery prepared in a preferred embodiment 2 of the present invention;
FIG. 2 is a graph comparing the discharge cycle performance of sodium-sulfur batteries assembled by positive electrode materials prepared in preferred example 2, comparative example 1 (without delignification treatment) and comparative example 2 (without KOH activation treatment) of the present invention;
FIG. 3 is a distribution diagram of the pore diameter of micropores of the tea residue powder after KOH activation, which is prepared by using the preferred embodiment 2 of the present invention; in the figure, dV/dD is used to plot the aperture D, that is, the change of the pore volume when the unit aperture is changed represents the change rate of the pore volume V along with the aperture D;
FIG. 4 is a scanning electron micrograph of the microstructure of the KOH-activated tea grounds obtained in accordance with the preferred embodiment 2 of the present invention;
FIG. 5 is a scanning electron microscope image of the microstructure of the tea grounds after KOH activation prepared in comparative example 1;
FIG. 6 is a scanning electron micrograph of the microstructure of the tea grounds before mixing with solid sublimed sulfur made using comparative example 2;
FIG. 7 is a scanning electron micrograph of the microstructure of powdered tea residue after KOH activation made using comparative example 3;
fig. 8 is a scanning electron microscope image of the microstructure of the activated tea grounds obtained by using the comparative example 4.
Detailed Description
Embodiments of the invention will be described in detail below with reference to the drawings, but the invention can be implemented in many different ways, which are defined and covered by the claims.
Example 1:
a preparation method of a sodium-sulfur battery positive electrode material specifically comprises the following steps:
step one, crushing 100 g of tea seed cake by using a common crusher, then continuing ball milling for 1-2 h, and sieving the ball-milled tea seed cake powder by using a sieve of 80-150 meshes.
Step two, taking the 2g of tea residue powder in 0.06L of NaOH and Na2SO3Soaking the product in the boiling solution for 3h, centrifugally collecting the precipitate after the product is cooled, washing the product for a plurality of times by using boiling deionized water, repeating the steps, collecting the precipitate, and freeze-drying the precipitate. Wherein, NaOH and Na2SO3NaOH and Na in the boiling mixed solution of (2)2SO3The concentration ratio of (A) to (B) is 4-7: 1.
step three, mixing the dried tea residue powder with KOH according to the mass ratio of 1:1 in absolute ethanol solvent for 30min, drying at room temperature, transferring the above material to a tube furnace, keeping at 800 ℃ for 2h under an Ar atmosphere with a purity of 99.999%, washing the calcined product with 1M HCl until the pH of the solution =7, and drying.
Step four, mixing the dry powder and the solid sublimed sulfur according to the mass ratio of 1: grinding according to the proportion of 1.5, uniformly mixing, reacting at 155 ℃ for 12 h, heating to 200 ℃ to remove surface sulfur, and obtaining the sodium-sulfur battery anode material.
Example 2:
a preparation method of a sodium-sulfur battery positive electrode material specifically comprises the following steps:
step one, crushing 100 g of tea seed cake by using a common crusher, then continuing ball milling for 1-2 h, and sieving the ball-milled tea seed cake powder by using a sieve of 80-150 meshes.
Step two, taking the 2g of tea residue powder in 0.06L of NaOH and Na2SO3Soaking the product in the boiling solution for 7 hours, centrifugally collecting the precipitate after the product is cooled, washing the product for a plurality of times by using boiling deionized water, repeating the steps, collecting the precipitate, and freeze-drying the precipitate. Wherein, NaOH and Na2SO3NaOH and Na in the boiling mixed solution2SO3The concentration ratio of (A) is 4-7: 1.
step three, mixing the dried tea residue powder with KOH according to the mass ratio of 1:1 in absolute ethanol solvent for 30min, drying at room temperature, transferring the above material to a tube furnace, keeping at 800 ℃ for 2h under an Ar atmosphere with a purity of 99.999%, washing the calcined product with 1M HCl until the pH of the solution =7, and drying.
Step four, mixing the dry powder and the solid sublimed sulfur according to the mass ratio of 1: grinding according to the proportion of 1.5, uniformly mixing, reacting at 155 ℃ for 12 h, heating to 200 ℃ to remove surface sulfur, and obtaining the sodium-sulfur battery anode material.
Example 3:
a preparation method of a sodium-sulfur battery positive electrode material specifically comprises the following steps:
step one, crushing 100 g of tea seed cake by using a common crusher, then continuing ball milling for 1-2 h, and sieving the ball-milled tea seed cake powder by using a sieve of 80-150 meshes.
Step two, taking the 2g of tea residue powder in 0.06L of NaOH and Na2SO3Soaking the product in the boiling solution for 12 h, centrifugally collecting the precipitate after the product is cooled, washing the product for a plurality of times by using boiling deionized water, repeating the steps, collecting the precipitate, and freeze-drying the precipitate. Wherein, NaOH and Na2SO3NaOH and Na in the boiling mixed solution of (2)2SO3The concentration ratio of (A) to (B) is 4-7: 1.
step three, mixing the dried tea residue powder with KOH according to the mass ratio of 1:1 in anhydrous ethanol solvent for 30min, drying at room temperature, transferring the above material to a tube furnace, maintaining at 800 ℃ for 2h (Ar atmosphere) under an Ar atmosphere with a purity of 99.999%, washing the calcined product with 1M HCl until the pH of the solution =7, and drying.
Step four, mixing the dry powder and the solid sublimed sulfur according to the mass ratio of 1: 1.5, grinding, uniformly mixing, reacting at 155 ℃ for 12 h, heating to 200 ℃ and removing surface sulfur to obtain the sodium-sulfur battery cathode material.
Example 4:
a preparation method of a sodium-sulfur battery positive electrode material specifically comprises the following steps:
step one, crushing 100 g of tea seed cake by using a common crusher, then continuing ball milling for 1-2 h, and sieving the ball-milled tea seed cake powder by using a sieve of 80-150 meshes.
Step two, taking the 2g of tea residue powder in 0.1L of NaOH and Na2SO3Soaking the product in the boiling solution for 7 hours, centrifugally collecting the precipitate after the product is cooled, washing the product for a plurality of times by using boiling deionized water, repeating the steps, collecting the precipitate, and freeze-drying the precipitate. Wherein, NaOH and Na2SO3NaOH and Na in the boiling mixed solution2SO3The concentration ratio of (A) to (B) is 4-7: 1.
step three, mixing the dried tea residue powder with KOH according to the mass ratio of 1: 0.5 in absolute ethanol solvent for 30min, drying at room temperature, transferring the above material to a tube furnace, keeping at 600 ℃ for 1h under an Ar atmosphere with a purity of 99.999%, washing the calcined product with 1M HCl until the pH of the solution =7, and drying.
Step four, mixing the dry powder and the solid sublimed sulfur according to the mass ratio of 1:1, grinding, uniformly mixing, reacting at 140 ℃ for 15 h, heating to 180 ℃ to remove surface sulfur, and thus obtaining the sodium-sulfur battery cathode material.
Example 5:
a preparation method of a sodium-sulfur battery positive electrode material specifically comprises the following steps:
step one, crushing 100 g of tea seed cake by using a common crusher, then continuing ball milling for 1-2 h, and sieving the ball-milled tea seed cake powder by using a sieve of 80-150 meshes.
Step two, taking the 2g of tea residue powder in 0.04L of NaOH and Na2SO3Soaking the product in the boiling solution for 7 hours, centrifugally collecting the precipitate after the product is cooled, washing the product for a plurality of times by using boiling deionized water, repeating the steps, collecting the precipitate, and freeze-drying the precipitate. Wherein, NaOH and Na2SO3NaOH and Na in the boiling mixed solution2SO3The concentration ratio of (A) to (B) is 4-7: 1.
step three, mixing the dried tea residue powder with KOH according to the mass ratio of 1: 2 in anhydrous ethanol solvent for 30min, drying at room temperature, transferring the above material to a tube furnace, keeping at 1000 ℃ for 1h under an Ar atmosphere with a purity of 99.999%, washing the calcined product with 1M HCl until the pH of the solution =7, and drying.
Step four, mixing the dry powder and the solid sublimed sulfur according to the mass ratio of 1: grinding according to the proportion of 1.5, uniformly mixing, reacting for 10 hours at 160 ℃, heating to 300 ℃ to remove surface sulfur, and obtaining the sodium-sulfur battery anode material.
Comparative example 1: (without delignification treatment)
Step one, crushing 100 g of tea seed cake by using a common crusher, then continuing ball milling for 1-2 h, and sieving the ball-milled tea seed cake powder by using a sieve of 80-150 meshes.
Step two, mixing the tea residue powder and KOH according to the mass ratio of 1:1 in absolute ethanol solvent for 30min, drying at room temperature, transferring the above material to a tube furnace, keeping at 800 ℃ for 2h under an Ar atmosphere with a purity of 99.999%, washing the calcined product with 1M HCl until the pH of the solution =7, and drying.
Step three, mixing the dry powder and the solid sublimed sulfur according to the mass ratio of 1: 1.5, uniformly mixing, reacting at 155 ℃ for 12 h, and heating to 200 ℃ to remove surface sulfur.
Comparative example 2: (without KOH activation treatment)
Comparative example 2 differs from example 2 in that: step three and KOH activation treatment were not performed, and the procedure was otherwise the same as in example 2.
Comparative example 3: (too high ratio of tea leaves to KOH)
Comparative example 3 differs from example 2 in that: the mass ratio of the tea residue powder subjected to lignin removal to KOH in the third step is 1: 0.008, otherwise the same as example 2.
Comparative example 4: (too low ratio of tea leaves to KOH)
Comparative example 4 differs from example 2 in that: the mass ratio of the tea residue powder subjected to lignin removal to KOH in the third step is 1: the rest was the same as example 2.
The positive electrode material of the sodium-sulfur battery prepared in the above examples 1 to 5 and comparative examples 1 to 4 was mixed with conductive carbon black and CMC (i.e., sodium carboxymethyl cellulose) in a mass ratio of 8: 1:1 to prepare slurry, coating the slurry on a copper foil, and drying the slurry in a vacuum drying oven at 60 ℃ for 12 hours to obtain the positive electrode plate of the sodium-sulfur battery. In a glove box filled with nitrogen, a metal sodium sheet was used as a negative electrode, Whatman GF/F glass fiber was used as a separator, and an appropriate amount of 1M electrolyte (NaClO) was added dropwise4+ EC/PC (1:1) v/v +3% FEC, where EC is ethylene carbonate; PC is polycarbonate; FEC is fluoroethylene carbonate) wetted diaphragm, assembled into a 2032 type coin cell. And transferring the assembled button battery into a blue-ray system, and testing the specific capacity. In order to better compare the cycling performance of different cathode materials, the same current density of 0.1C (1C =1675 mAh/g) was used for testing, and the voltage window was 0.5-2.8V, and the specific test results are shown in table 1.
Table 1 experimental results of discharge test of sodium-sulfur battery assembled by different cathode materials at current density of 0.1C
As is clear from Table 1, in example 2, the specific volume at first discharge and the specific volume at 100 th discharge were measuredThe capacity and the average coulombic efficiency after 100 times of circulation are both excellent, the first discharge specific capacity is 1673mAh/g, the first discharge specific capacity is 712mAh/g, and the average coulombic efficiency after 100 times of circulation is up to 98.6%. This is achieved by the combination of suitable delignification time and suitable KOH usage, and example 2 possesses a higher sulfur content (compared to other biomass charcoal sodium sulfur battery positive electrode materials), which greatly enhances the practical application potential of the invention. As can be seen from comparative examples 1 to 3, the pretreated tea grounds were treated with NaOH and Na2SO3The obtained sodium-sulfur battery positive electrode material is soaked in the boiling solution for 7 hours, and when delignification treatment is carried out, the battery assembled by the prepared sodium-sulfur battery positive electrode material can save more energy and is more environment-friendly on the premise of keeping good electrochemical performance. When the delignification treatment time is less than 7h (example 1), the first discharge specific capacity and the 100 discharge specific capacity are reduced, which is probably because the delignification degree is not complete enough and a small amount of slightly massive biomass exists, so that the micropore content is reduced after subsequent KOH activation, and small sulfur molecules (S) are reduced2-4) Confinement within the micropores. In the experiments for exploring the optimum amount of KOH (examples 3-5), it was found that the mass ratio of the tea seed cake after delignification to KOH was 1:1, better electrochemical performance can be obtained. This is due to the fact that when the amount of KOH used is reduced (example 4), the degree of activation for the biomass is not complete enough, exhibiting a small specific surface area (1172 m)2In terms of a/g) and micropore volume (0.517 cm)3/g), the pore-forming effect is not obvious; when the amount was increased (example 5), it resulted in a small amount of structural disruption, loss of active material, and ineffective polysulfide shuttling restriction. However, the overall effect of example 1 and examples 3 to 5 was excellent.
Fig. 1 is a thermogravimetric analysis of the positive electrode material of the sodium-sulfur battery obtained in example 2, and it can be seen from fig. 1 that sulfur starts to volatilize at about 200 ℃ and almost completely volatilizes at 500 ℃, indicating that the sulfur content reaches 61.9% by mass change. Also, in the thermogravimetric analysis curve of example 2, there is a significant turning point (about 270 ℃), when the temperature is less than 270 ℃, sulfur on the surface of the activated tea grounds (i.e., the charcoal host) is mainly volatilized, and when the temperature is more than 270 ℃, sulfur in the micropores of the charcoal host is mainly volatilized. It is believed that the sulfur loading within the pores of the carbon host is more robust and reduces the loss of active species during cycling. The activated tea residue powder is used as the host material of the sodium-sulfur battery anode, so that high specific capacity is maintained while high sulfur content is realized, and certain feasibility is realized for practical application.
To compare the superiority of the two-step process, we tested the electrochemical performance of comparative examples 1, 2. The experimental results show that excellent electrochemical performance cannot be obtained by only performing KOH activation or only delignification treatment, but from the comparison of the two, comparative example 1 can exhibit a much higher specific discharge capacity than comparative example 2 because a good microporous structure cannot be constructed by only a single delignification step, the presence of polysulfide cannot be avoided, and thus, electrochemical performance is deteriorated. Therefore, the method combining the two steps of delignification and KOH activation has visible advantages, the delignification process can effectively loosen the structure of the bulk tea seed cake, increase the subsequent contact area with KOH, and ensure that the KOH activation is more uniform. Meanwhile, in the delignification process, mesoporous pores appear on plant cell walls along with the swelling of biomass, and when KOH is activated, KOH and the biomass react as follows:
6KOH + 2C → 2K + 3H2 +2K2CO3
the presence of a hierarchical pore structure improves the accessibility of the electrolyte and can accommodate more sulfur than a single microporous structure. The biomass derived carbon host with high specific surface area, high micropore volume and hierarchical pore structure can still maintain good electrochemical performance on the premise of higher sulfur loading.
FIG. 2 is a graph showing a comparison of discharge cycle characteristics of sodium-sulfur batteries assembled using the positive electrode materials obtained in example 2, comparative example 1 and comparative example 2, in which tea residue powder was mixed with NaOH and Na2SO3Soaking in boiling solution for 7h for delignification treatmentAnd then KOH activation is carried out to prepare the cathode material with the best electrochemical performance. While the single use of the positive electrode material prepared in one of the steps (delignification only or KOH activation only) results in poor electrochemical performance due to the low micropore content (delignification only) and insufficient mesoporous and macroporous structure (KOH activation only). This is due to the formation and shuttling of polysulfides (delignification only) and poor electrolyte accessibility (KOH activation only). Thus, both delignification and KOH activation processes contribute to the improvement of electrochemical performance.
FIG. 3 is a plot of the pore size distribution of the tea grounds (i.e., charcoal hosts) after KOH activation prepared in example 2. The dV/dD is plotted against the pore diameter D in FIG. 3, i.e., the change in pore volume per unit pore diameter change, representing the rate of change of pore volume with pore diameter. The result shows that most micropores are distributed at about 0.6 nm and can only accommodate small S molecules (S)2-4). According to the test results of nitrogen adsorption and desorption, example 2 showed the largest specific surface area (1362 m)2G), total pore volume (0.739 cm)3G) and micropore volume (0.575 cm)3In terms of/g). Meanwhile, the specific surface area of the mesopores and the macropores is relatively high, so that the accessibility and the sulfur carrying capacity of the electrolyte can be effectively improved due to the combination of a delignification and KOH activation two-step method.
Fig. 4 is a scanning electron micrograph of the carbon host microstructure of the tea grounds (i.e., carbon hosts) after KOH activation made in example 2. As can be seen from fig. 4, the microstructure of the activated tea grounds is a three-dimensional porous structure. After delignification, the tea seed cake biomass which is originally in a massive state swells and is crushed, and mesopores appear on cell walls, so that the specific surface area of the tea seed cake biomass is greatly improved; and the subsequent mixing with KOH is more uniform and deeper, and a good pore-forming effect is led out.
Fig. 5 is a scanning electron micrograph of the microstructure of the tea grounds before mixing with solid sublimed sulfur prepared using comparative example 1. As can be seen from fig. 5, the microstructure of the tea residue powder which is not delignified and is only subjected to KOH activation can show an obvious pore structure, but the dispersibility of the nanoparticles is weak, the agglomeration phenomenon is serious, and the structure is not favorable for maintaining the stability of the electrode of the subsequent sodium-sulfur battery in the circulating process.
Fig. 6 is a scanning electron microscope image of the microstructure of the tea powder after KOH activation made in comparative example 2. From fig. 6, it can be seen that the biomass char after delignification swells and breaks up in large lumps, but since KOH activation is not performed, a good microporous structure is not formed. The structure can cause the formation of polysulfide and the occurrence of shuttle effect in the circulation process of a sodium-sulfur battery with subsequent composition, and the specific discharge capacity is very low.
Fig. 7 is a scanning electron micrograph of the microstructure of the tea powder after KOH activation made in comparative example 3. As can be seen from FIG. 7, when the ratio of tea leaves to KOH is higher than 1: at 0.5, the activation degree of the tea residue powder is low, and compared with the tea residue powder shown in figure 4, the tea residue powder has fewer obvious pore structures and more massive structures, and the structure is not beneficial to the subsequent formation of small sulfur molecules (S) in the circulation process of the sodium-sulfur battery2-4) Is limited by the physical limitations of (a).
Fig. 8 is a scanning electron microscope image of the microstructure of the tea powder after KOH activation made in comparative example 4. As can be seen from FIG. 8, when the ratio of tea leaves to KOH is less than 1: 2, the hierarchical pore structure of the carbon host is obviously damaged, and the open and broken pore structure is not beneficial to the subsequent formation of small sulfur molecules (S) in the circulation process of the sodium-sulfur battery2-4) Is limited by the physical limitations of (c). As can be seen from comparative examples 3 and 4, the ratio of the tea residue to KOH is critical, when KOH is too much, the hierarchical porous structure is broken, and when KOH is too little, the pore-forming is incomplete, and the pore-forming effect is not good.
In summary, the invention provides a preparation method of a sodium-sulfur battery cathode material, and biomass charcoal after delignification and KOH activation has a good pore structure, so that S can be enabled to be in a good pore structure8The molecule is treated with S during the subsequent cycle2-4The sodium-sulfur battery can avoid the generation of soluble polysulfide, thereby improving the specific capacity of the sodium-sulfur battery. The invention uses a two-step method of delignification and KOH activation to realize the construction of a high specific surface area and a hierarchical porous structure, focuses on 0.6 nm micropores to ensure that the existence form of sulfur is small sulfur molecules, and greatly avoids the shuttle of polysulfide. Biomass charcoal subjected to delignification and KOH activationThe abundant mesopores and macropores are beneficial to the loading of high-content sulfur and the accessibility of electrolyte, thereby improving the electrochemical performance of the electrolyte.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (6)
1. The preparation method of the positive electrode material of the sodium-sulfur battery is characterized by comprising the following steps of:
step one, tea seed cake is pretreated to obtain tea seed cake powder;
step two, adding the tea residue powder prepared in the step one into NaOH and Na2SO3Soaking the tea leaves in the boiling mixed solution for 3-12 h, centrifugally collecting precipitate after the product is cooled, washing by using boiling deionized water, and freeze-drying to obtain lignin-removed tea leaf powder;
step three, grinding and drying the tea residue powder without the lignin prepared in the step two and KOH in an absolute ethyl alcohol solvent, calcining for 1-3 h in inert gas at the temperature of 600-1000 ℃, washing and drying the calcined product by using HCl solution to obtain activated tea residue powder; wherein the mass ratio of the lignin-removed tea residue powder to KOH is 1: 0.1 to 5;
step four, mixing the activated tea residue powder and the solid sublimed sulfur according to the mass ratio of 1: 1-2, uniformly mixing, reacting for 10-15 h at the temperature of 140-160 ℃, heating to the temperature of 180-300 ℃ to remove surface sulfur, and obtaining the sodium-sulfur battery anode material.
2. The preparation method of the sodium-sulfur battery positive electrode material according to claim 1, wherein in the first step, tea seed meal is pretreated, specifically: crushing the tea seed cake by a crusher, then carrying out ball milling for 1-2 h, and sieving the tea residue powder subjected to ball milling by a sieve of 80-150 meshes.
3. The method for preparing the positive electrode material of the sodium-sulfur battery as claimed in claim 1, wherein in the second step, each gram of tea residue powder is dispersed in 0.04-0.1L of NaOH and Na2SO3In the boiling mixed solution of (1); NaOH and Na2SO3NaOH and Na in the boiling mixed solution2SO3The concentration ratio of (A) to (B) is 4-7: 1.
4. the method for preparing the positive electrode material of the sodium-sulfur battery according to claim 1, wherein the concentration of the HCl solution is 1M in the third step.
5. The method for preparing the positive electrode material of the sodium-sulfur battery according to claim 1, wherein in the third step, the inert gas is nitrogen or argon with a purity of 99.999%.
6. The method for preparing the positive electrode material of the sodium-sulfur battery as claimed in any one of claims 1 to 5, wherein in the third step, the calcination process is carried out in a tube furnace.
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| Publication number | Priority date | Publication date | Assignee | Title |
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Citations (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103531759A (en) * | 2013-09-23 | 2014-01-22 | 广州市香港科大***研究院 | Two-step adsorption preparation method of high magnification sulphur/mesoporous and microporous carbon HAC (honeycomb activated carbon) lithium sulphur battery anode composite material |
| CN106006636A (en) * | 2016-05-19 | 2016-10-12 | 中国科学院青岛生物能源与过程研究所 | Biomass-based nitrogen-doped porous carbon material, and preparation method and application thereof |
| CN106299298A (en) * | 2016-09-21 | 2017-01-04 | 深圳市沃特玛电池有限公司 | A kind of preparation method of sulfur/porous carbon composite positive pole |
| CN108365210A (en) * | 2018-04-12 | 2018-08-03 | 桂林电子科技大学 | A kind of activated carbon carbon-sulfur materials and its preparation method and application |
| CN109081342A (en) * | 2018-08-03 | 2018-12-25 | 成都城电电力工程设计有限公司 | A kind of biomass porous active carbon of nipa palm leaf and its preparation method and application |
| CN110176597A (en) * | 2019-06-20 | 2019-08-27 | 西北师范大学 | A kind of preparation and application of biomass carbon/sulphur composite material |
| CN111320172A (en) * | 2020-02-28 | 2020-06-23 | 中国矿业大学 | Directional synthesis method and application of biomass activated carbon-based electrode material containing micropore-mesoporous pore canal |
| CN111785912A (en) * | 2019-04-03 | 2020-10-16 | 中南大学 | Preparation method of novel porous carbon cathode lithium-sulfur battery |
| CN111841495A (en) * | 2020-07-13 | 2020-10-30 | 安徽农业大学 | Preparation method of porous tea residue biochar with high specific surface area |
| CN112194114A (en) * | 2020-10-10 | 2021-01-08 | 中北大学 | Method for preparing three-dimensional pore channel structure by taking wood as raw material |
| CN112490446A (en) * | 2020-11-08 | 2021-03-12 | 北京科技大学 | Preparation method of Co-CNT @ CF three-dimensional self-supporting lithium-sulfur battery positive electrode material |
| CN112928262A (en) * | 2021-02-24 | 2021-06-08 | 山东科技大学 | Sodium-sulfur battery and preparation method thereof |
| CN112928255A (en) * | 2021-01-25 | 2021-06-08 | 合肥工业大学 | Lithium-sulfur battery composite positive electrode material and preparation method and application thereof |
| CN113060719A (en) * | 2021-03-17 | 2021-07-02 | 山东省科学院新材料研究所 | Wood-based carbon foam and preparation method thereof, cathode electrocatalyst, cathode and metal-air battery |
| CN113683089A (en) * | 2021-08-30 | 2021-11-23 | 长沙联美生物科技有限责任公司 | Layered porous biochar and preparation method and application thereof |
| CN114277598A (en) * | 2021-03-30 | 2022-04-05 | 赣南师范大学 | Preparation method of hollow and porous hybrid cells and bamboo dissolving pulp |
-
2022
- 2022-05-06 CN CN202210484053.XA patent/CN114583146B/en active Active
Patent Citations (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103531759A (en) * | 2013-09-23 | 2014-01-22 | 广州市香港科大***研究院 | Two-step adsorption preparation method of high magnification sulphur/mesoporous and microporous carbon HAC (honeycomb activated carbon) lithium sulphur battery anode composite material |
| CN106006636A (en) * | 2016-05-19 | 2016-10-12 | 中国科学院青岛生物能源与过程研究所 | Biomass-based nitrogen-doped porous carbon material, and preparation method and application thereof |
| CN106299298A (en) * | 2016-09-21 | 2017-01-04 | 深圳市沃特玛电池有限公司 | A kind of preparation method of sulfur/porous carbon composite positive pole |
| CN108365210A (en) * | 2018-04-12 | 2018-08-03 | 桂林电子科技大学 | A kind of activated carbon carbon-sulfur materials and its preparation method and application |
| CN109081342A (en) * | 2018-08-03 | 2018-12-25 | 成都城电电力工程设计有限公司 | A kind of biomass porous active carbon of nipa palm leaf and its preparation method and application |
| CN111785912A (en) * | 2019-04-03 | 2020-10-16 | 中南大学 | Preparation method of novel porous carbon cathode lithium-sulfur battery |
| CN110176597A (en) * | 2019-06-20 | 2019-08-27 | 西北师范大学 | A kind of preparation and application of biomass carbon/sulphur composite material |
| CN111320172A (en) * | 2020-02-28 | 2020-06-23 | 中国矿业大学 | Directional synthesis method and application of biomass activated carbon-based electrode material containing micropore-mesoporous pore canal |
| CN111841495A (en) * | 2020-07-13 | 2020-10-30 | 安徽农业大学 | Preparation method of porous tea residue biochar with high specific surface area |
| CN112194114A (en) * | 2020-10-10 | 2021-01-08 | 中北大学 | Method for preparing three-dimensional pore channel structure by taking wood as raw material |
| CN112490446A (en) * | 2020-11-08 | 2021-03-12 | 北京科技大学 | Preparation method of Co-CNT @ CF three-dimensional self-supporting lithium-sulfur battery positive electrode material |
| CN112928255A (en) * | 2021-01-25 | 2021-06-08 | 合肥工业大学 | Lithium-sulfur battery composite positive electrode material and preparation method and application thereof |
| CN112928262A (en) * | 2021-02-24 | 2021-06-08 | 山东科技大学 | Sodium-sulfur battery and preparation method thereof |
| CN113060719A (en) * | 2021-03-17 | 2021-07-02 | 山东省科学院新材料研究所 | Wood-based carbon foam and preparation method thereof, cathode electrocatalyst, cathode and metal-air battery |
| CN114277598A (en) * | 2021-03-30 | 2022-04-05 | 赣南师范大学 | Preparation method of hollow and porous hybrid cells and bamboo dissolving pulp |
| CN113683089A (en) * | 2021-08-30 | 2021-11-23 | 长沙联美生物科技有限责任公司 | Layered porous biochar and preparation method and application thereof |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116553520A (en) * | 2023-06-07 | 2023-08-08 | 苏州科技大学 | Preparation method and application of high-performance room-temperature sodium-sulfur battery positive electrode material |
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