阅读说明：本技术 超声辅助法制备氮、硫共掺杂的鱿鱼墨衍生碳/石墨烯复合材料及其在储钾领域的应用 (Nitrogen and sulfur co-doped squid ink derived carbon/graphene composite material prepared by ultrasonic-assisted method and application thereof in potassium storage field ) 是由 柳伟 胡茂锋 段志鹏 杜永旭 于 2021-09-17 设计创作，主要内容包括：本发明提供了一种以海洋生物废弃物鱿鱼墨为原料,使用细胞粉碎机,通过超声波将鱿鱼墨,硫粉和氧化石墨烯复合在一起制备氮、硫共掺杂碳材料的方法,并将其应用于钾离子电池。该方法是将酸洗后的鱿鱼墨和硫粉加入到去离子水中,利用细胞粉碎机将其在水中均匀分散,然后将此混合液加入到已被超声波均匀分散的氧化石墨烯悬浊液中,将混合液继续进行细胞粉碎。由于超声波强烈的机械作用,氧化石墨烯被超声波打散并且包覆在鱿鱼墨的表面,进一步通过冷冻干燥处理,对冻干样品进行高温碳化,制得氮、硫共掺杂生物质衍生碳纳米材料,并表现出优良的钾离子存储性能。(The invention provides a method for preparing a nitrogen and sulfur co-doped carbon material by compounding squid ink, sulfur powder and graphene oxide together by using marine biological waste squid ink as a raw material and using a cell crusher through ultrasonic waves, and the method is applied to a potassium ion battery. Adding pickled squid ink and sulfur powder into deionized water, uniformly dispersing the squid ink and the sulfur powder in the water by using a cell crusher, then adding the mixed solution into a graphene oxide turbid liquid uniformly dispersed by ultrasonic waves, and continuously carrying out cell crushing on the mixed solution. Due to the strong mechanical action of ultrasonic waves, graphene oxide is scattered by the ultrasonic waves and coated on the surface of the squid ink, and a freeze-dried sample is subjected to high-temperature carbonization through further freeze drying treatment to prepare the nitrogen and sulfur co-doped biomass derived carbon nano material and show excellent potassium ion storage performance.)

1. The application of the method for preparing the nitrogen and sulfur co-doped carbon nano material by compounding squid ink and sublimed sulfur serving as raw materials with graphene oxide under the ultrasonic action of a cell crusher in the field of potassium storage is characterized by comprising the following steps of: (a) screening of biomass precursors: the yield of marine biomass is high, large-scale development and use are facilitated, the cost is low, and no pollution is caused; the squid ink is composed of a large number of nanospheres, each squid ink sphere has a core-shell structure consisting of a melanin core and a protein shell, and the contained biological amino acid can realize in-situ doping of N element in the carbonization process; (b) pretreatment: cleaning squid ink with dilute sulfuric acid, and stirring for 12 h; washing the product with deionized water for many times in a centrifuge at the rotating speed of 9000 rpm/min, and freeze-drying to obtain a precursor product; (c) mixing: carrying out cell crushing on a certain amount of squid ink and sulfur powder in an aqueous solution, simultaneously carrying out ultrasonic crushing on graphene oxide in water to form a suspension, mixing the two solutions, carrying out cell crushing again, and carrying out freeze drying treatment to obtain brownish black powder; (d) carbonizing: and (3) putting the brown black powder into a corundum porcelain boat, introducing argon into a tube furnace for carbonization, taking out a sample after the temperature is cooled to room temperature, cleaning the sample by using a dilute hydrochloric acid solution, washing the sample to be neutral by using deionized water, and drying the sample to obtain black powder.

2. The method for producing a biomass carbon material according to claim 1, characterized in that: in the step a, the biomass squid ink is rich in reserve, low in cost, nano in size and suitable for constructing a hierarchical porous structure material; and the squid ink contains a large amount of nitrogen element, and the obtained N, S co-doped carbon material can promote the adsorption of potassium ions and improve the performance of the battery by further doping the sulfur element.

3. The method for producing a biomass-derived carbon material according to claim 1, wherein: in step b, 100 mL of a solution having a concentration of 6 mol. L is measured^-1Adding a certain amount of squid ink into the sulfuric acid solution, mixing and stirring for 12 hours, and fully removing impurities in the squid ink; pouring the stirred solution into a centrifuge tube, centrifuging for 20min at the rotating speed of 9000 rpm/min, washing for multiple times by deionized water until the solution is neutral, and freeze-drying the sample for 72 h.

4. The method for producing a biocarbon material as claimed in claim 1, wherein: in the step c, adding the pickled squid ink and the sublimed sulfur into 20ml of deionized water according to the mass ratio of 1:0.5-1:2, and carrying out ultrasonic treatment for 20min by using a cell crusher to uniformly disperse the squid ink and the sublimed sulfur; adding 0.02g of graphene oxide into 20ml of deionized water, and carrying out ultrasonic treatment for 10min by using a cell crusher; then mixing the two solutions, and crushing the cells for 30min again to obtain uniformly dispersed black suspension; obtaining brown black powder after freeze drying treatment.

5. The method for producing a biocarbon material as claimed in claim 1, wherein: in the step d, the carbonization temperature of the precursor subjected to freeze drying is 500-; 1 mol. L for sintered sample^-1Washing with hydrochloric acid for 2h, and washing with water and ethanol to neutrality.

6. The method for preparing nitrogen and sulfur co-doped squid ink derived carbon/graphene composite carbon material through ultrasound assistance according to claims 1-5, is characterized in that: fully compounding the squid ink, the sublimed sulfur and the graphene oxide through the mechanical action and the cavitation action of ultrasonic waves of the cell crusher to form a composite structure of the squid ink ball coated by the graphene oxide; in the high-temperature sintering process, sulfur and nitrogen are doped in biological carbon spheres, and a large number of active sites are introduced; the composite micro-nano structure jointly constructed by the graphitized region provided by the graphene oxide and the disordered region caused by element doping shows excellent potassium ion storage performance.

Technical Field

The invention belongs to the field of electrochemical energy storage devices, and provides a nitrogen and sulfur co-doped biomass derived carbon/graphene composite material prepared by using biological waste squid ink, sublimed sulfur and graphene oxide as raw materials and using an ultrasonic-assisted method, and an application of the carbon/graphene composite material in a potassium ion battery.

Background

With the development of society, fossil energy is being exhausted when being overused by people, the energy crisis is gradually deepened, and environmental protection also gradually becomes a problem which is more and more emphasized by people around the world. Under the social trend, the development of new energy storage materials is receiving more and more attention. Among them, the lithium ion battery is most widely studied. With the large-scale application of lithium ion batteries, the future market of lithium ion batteries is not clear due to the shortage of lithium resources. In order to solve this problem, it is inevitable to find a substitute for lithium ion batteries. In contrast, sodium (23000 ppm) and potassium (17000 ppm) in the earth's crust are abundant and possess electrochemical storage mechanism similar to that of lithium ion, so that potassium ion batteries and sodium ion batteries become new energy storage devices in the future.

Compared with lithium ion batteries and sodium ion batteries, potassium ion batteries have lower cost and abundant resources; has a lower reduction potential (≈ 2.936V); the energy density is very high; k⁺Less lewis acidity and solvated ions, the conductivity and number of solvated and migrated potassium ions being greater than the conductivity and number of lithium ions; k⁺The low desolvation capacity can promote faster diffusion at the electrolyte/electrode interface, etc., making it more advantageous in the field of large-scale energy storage. For the potassium ion battery negative electrode material, since the size of potassium ions is large, it is required to have a large space to accommodate K⁺(ii) a While also requiring a stable structure to withstand reversible K⁺Volume change during intercalation/deintercalation. Carbon materials are suitable electrode materials for potassium ion batteries because of their low cost and excellent cycling stability. Wherein, the biomass carbon has the advantages of low cost, wide source and environmental friendlinessGood, rich oxygen-containing functional groups on the surface and higher activity, and is a potential potassium ion battery cathode material. The squid ink is rich in organic matters and a unique nano structure thereof, so that the squid ink becomes a more ideal electrode material. The biological carbon material and the carbon-based composite material are prepared as electrode materials by utilizing the biomasses such as the squid ink through a series of means, and simultaneously, the adsorption and storage of potassium ions are promoted by utilizing the doping of various elements, so that the problems of volume expansion and the like are relieved, and the performance of a corresponding energy storage device is improved.

This patent utilizes the mechanical mixing effect of ultrasonic wave based on marine living beings squid china ink as the raw materials, with the even cladding of graphene oxide on squid china ink surface, realizes simultaneously sulphur doping and the nitrogen doping of self, utilizes freeze-drying, and the high temperature carbonization technique comes to realize conductivity and surface functional group and defect regulation and control to biomass derived carbon material. The nitrogen and sulfur co-doped squid ink/graphene composite carbon material is obtained, and the structure of graphite carbon and amorphous carbon coupling is realized, so that the potassium storage performance of the material can be effectively improved.

Disclosure of Invention

The invention aims to solve the technical problem of providing a nitrogen and sulfur co-doped squid ink/graphene composite carbon material prepared by taking squid ink as a raw material, and the carbon material is applied to a potassium ion battery and is used as an active material to assemble a potassium ion battery energy storage device. In order to solve the technical problem, the technical scheme adopted by the invention is as follows:

firstly, dispersing pickled squid ink and sublimed sulfur in a deionized water solution, carrying out ultrasonic treatment for 20min by using a cell crusher, adding the mixture into the deionized water solution in which graphene oxide is dispersed, and continuing carrying out cell crushing and ultrasonic treatment for 30 min. And (3) after freeze drying, carrying out high-temperature carbonization-acid washing and other synthesis steps to obtain the final carbon material. And mixing the obtained carbon negative electrode material, conductive acetylene black and a binder according to the ratio of 7:2:1, and coating the mixture on an Al sheet to prepare the negative electrode sheet of the battery. And assembling the positive electrode shell, the carbon sheet, the diaphragm, the potassium block and the negative electrode shell into a potassium ion battery in a glove box filled with argon, and testing the cycle performance and the rate capability of the potassium ion battery in a blue-electricity system.

Compared with the prior art, the invention has the beneficial effects that: (1) according to the invention, the nitrogen and sulfur co-doped squid ink/graphene composite carbon material is prepared by using the squid ink which is a marine biological waste as a raw material, so that the cost is low, the resource is rich, the waste of the resource is reduced, and a thought is provided for efficiently utilizing the marine biological waste. Meanwhile, the squid ink is rich in protein and contains a large amount of nitrogen elements, the self element doping can be realized in the high-temperature carbonization process, more active sites and defects are improved for the carbon material, the pyridine nitrogen and pyrrole nitrogen have higher contents, the adsorption on potassium ions is facilitated, a high pseudo-capacitance ratio is provided, and the good potassium storage performance is endowed to the material.

(2) According to the invention, the squid ink and the sulfur powder can be better dispersed in deionized water by adopting the ultrasonic action of the cell crusher, and the graphene oxide can be smashed and uniformly coated on the squid ink by virtue of the cavitation effect generated by strong ultrasonic impact force, so that a unique shape and structure are obtained. After high-temperature sintering, the squid ink has higher nitrogen content, but cannot be completely carbonized, so that certain conductivity is lacked; on the basis, graphene oxide is introduced, after sintering, the graphene can provide excellent conductivity, the charge transfer speed is improved, the composite material has a large number of defects and excellent conductivity, a graphite carbon and amorphous carbon coupled structure is formed, and the potassium storage performance of the material is further improved. Meanwhile, the structure of the squid ink coated by the graphene can endow the carbon material with better structural stability, and the volume change of potassium ions in the adsorption and desorption process is reduced. In addition, the defects generated on the surface of the graphene oxide after high-temperature sintering can also have good adsorption effect on potassium ions. The synergistic effect of the characteristics of the materials is combined, so that the material has excellent performance in the potassium ion battery.

(3) By sulfur doping of the material, not only is a sulfur-rich functional group introduced, but also an oxidation-reduction reaction occurs in the potassium storage process so as to provide high capacity; and more defects are introduced into the material, so that the interlayer spacing of the material is enlarged, and the electrochemical performance of the material is promoted. More importantly, the sulfur doping can adjust the proportion of pyridine nitrogen, pyrrole nitrogen and graphite nitrogen, promote the formation of high-activity pyridine nitrogen, and the synergistic effect also promotes the electrochemical performance of the material. The squid ink biomass derived carbon obtained by the technology has excellent potassium ion storage capacity, is simple in preparation process, basically has no pollution to the environment, is expected to realize large-scale application, and has a certain development prospect on how to relieve the problem of current energy supply shortage.

Drawings

Fig. 1 is a Scanning Electron Microscope (SEM) photograph of the carbon-based composite material obtained in example 1.

Fig. 2 is a Scanning Electron Microscope (SEM) photograph of the carbon-based composite obtained in example 2.

Fig. 3 is a Scanning Electron Microscope (SEM) photograph of the carbon-based composite obtained in example 3.

Fig. 4 is an X-ray photoelectron spectroscopy (XPS) curve of the carbon-based composite prepared in example 1 of the present invention.

Fig. 5 shows the rate capability of a half-cell when the carbon-based composite material prepared in example 1 of the present invention is used as an anode material of a potassium ion battery.

FIG. 6 is a graph of carbon-based composite material prepared in example 1 of the present invention as an anode material for potassium ion battery at 5A g^-1Cycling performance at current density.

Detailed Description

The invention will now be described with reference to the following specific examples, but is not limited to the examples.

Example 1

Weighing 0.5g of pickled squid ink, putting the squid ink into 20ml of deionized water, uniformly stirring, adding 0.5g of sublimed sulfur, putting the liquid into a cell crusher, and performing ultrasonic treatment for 20min to uniformly disperse the squid ink and sulfur powder in the deionized water; then weighing 0.02g of graphene oxide, adding the graphene oxide into 20ml of deionized water, and carrying out ultrasonic treatment for 10min by using a cell crusher to obtain a uniformly dispersed graphene oxide suspension; finally mixing the two liquids, continuing ultrasonic treatment for 30min to compound the squid ink and the graphene oxide under the action of ultrasonic waves, and freeze-drying after full reactionAnd 72 h. Placing the freeze-dried product into a porcelain boat, and heating at 3 deg.C/min in a tube furnace with argon as inert gas^-1The temperature is raised to 500 ℃ at the temperature raising rate, and the temperature is kept for 2h for carbonization. After naturally cooling to room temperature, the calcined sample was taken out. With 1 mol. L^-1And (3) cleaning impurities in the product by using a hydrochloric acid solution, cleaning the impurities for three times by using ethanol and deionized water, finally cleaning the impurities to be neutral, collecting the impurities, and drying the impurities in an oven at 80 ℃ to obtain a black powder product. As can be seen from fig. 1, the composite material is a composite structure of the squid carbon spheres coated by graphene, and the structure can provide a certain structural stability for the carbon material and provide a certain cycle stability in the charge and discharge processes of the potassium ion battery.

Example 2

The method of this example is substantially the same as example 1, except that the squid ink/graphene oxide composite material is directly sintered without adding sublimed sulfur. As can be seen from the SEM in fig. 2, the morphology of the final product is substantially the same as that in fig. 1, and both are a structure in which the squid ink carbon spheres are uniformly coated with graphene.

Example 3

In the method of the embodiment, the squid ink after acid washing is directly treated without adding the sulfur powder and the graphene oxide in the embodiments 1 and 2, and the subsequent experimental steps are the same as the embodiments 1 and 2. As can be seen from the SEM of fig. 3, the carbon material consists of a close packing of many carbon spheres with a diameter of about 80nm, and the lack of graphene coating adversely affects its structural stability.

Application example 1

Uniformly mixing the carbon composite material obtained after the calcination activation treatment, conductive acetylene black and a binder (polyvinylidene fluoride) in a mass ratio of 7:2:1, uniformly dispersing the slurry and carbon powder by using a 1-methyl-2-pyrrolidone (NMP) solution to obtain black viscous liquid, and finally coating the liquid on an aluminum foil to prepare the electrode plate. Assembling the battery in a glove box filled with argon, and assembling the potassium ion half-battery by using the carbon negative electrode material and the potassium block, wherein the electrolyte used is 1 mol.L^-1KFSI of (1) is dissolved in an EC/DEC electrolyte. Finally, in a blue electric work stationTest for electrochemical performance. The results are shown in FIGS. 5 and 6.

From XPS of fig. 4, it can be seen that the carbon material prepared in example 1 contains four elements, i.e., carbon, nitrogen, oxygen and sulfur, and represents that the carbon material has rich defect structures and rich surface functional groups, which can promote potassium ion adsorption and provide the electrode material with excellent rate and cycle performance. From the above point of view, the half-cell rate performance and cycle performance of fig. 5 and 6 can be verified at 0.1A g^-1Has a low current density of 510mAh g^-1High reversible capacity, even at 10A g^-1Can also have 170mAh g under the high current density^-1And at 5A g^-1Can maintain 290mAh g in 1400 cycles under the condition of high current density^-1High reversible capacity and long cycle life.