Energy storage carbon material, method of making and use thereof

Abstract

The present application relates to the technical fields of wastewater purification and energy storage material, and discloses an energy storage carbon material, a preparation method and application thereof.The method comprises the following steps: carbonizing biomass waste enriched with metal ions to obtain an energy storage carbon material.The energy storage carbon material can be used to prepare a secondary metal / ion battery.The energy storage carbon material prepared by the present application can promote the uniform deposition of metal in the charging and discharging process, avoid the safety problems caused by dendrite growth, and at the same time, the metal ions in industrial wastewater can be used to prepare high-value-added secondary battery energy storage materials by means of a simple and low-cost method of biosorption.

Description

Technical Field

[0001] This invention relates to the field of wastewater purification and energy storage materials technology, specifically to an energy storage carbon material, its preparation method, and its application. Background Technology

[0002] Industries such as chemical, mining, pharmaceutical, printing and dyeing, and papermaking generate large amounts of industrial wastewater containing heavy metal ions (such as mercury, chromium, copper, cadmium, and lead). If this wastewater is discharged indiscriminately without effective control and proper treatment, it will cause serious environmental pollution and resource waste. Currently, adsorption is a commonly used method for treating such industrial wastewater containing heavy metal ions. Agricultural and forestry wastes (such as rice straw, rice husks, peanut shells, grapefruit peels, wood, bamboo, shells, and lobsters) contain active groups (including hydroxyl, carboxyl, and amino groups), which can serve as adsorption sites for heavy metals. However, regardless of the biomass material used as the raw material for heavy metal adsorbents, harmful solid waste adsorbents are still generated after adsorbing heavy metals. Therefore, the post-treatment or further utilization of these hazardous solid waste adsorbents remains a key issue in the field of adsorption materials.

[0003] Currently, post-treatment methods for plant adsorbents enriched with heavy metals include incineration and composting. Incineration involves combustion with excess air, which may cause secondary pollution from fly ash containing metals, and its high energy consumption increases operating costs. Composting utilizes microorganisms to degrade pollutants in solid waste, but its treatment cycle is long (usually two to three months), large-scale treatment is costly, and the leachate generated during the composting process needs to be strictly controlled.

[0004] Faced with the new energy landscape and climate change, the development of science and technology has gradually shifted towards the development and utilization of green, renewable, and clean energy. Energy storage technology can convert clean energy sources that are difficult to store, such as wind and solar power, into more convenient and economical forms. Secondary batteries are the most important part of energy storage technology, offering advantages such as ease of use, low environmental pollution, and lack of geographical limitations. However, to achieve large-scale application, their energy density and production costs still need further optimization. Biomass has broad application prospects in the energy and environmental fields. Biomass carbon not only possesses a large specific surface area, rich and adjustable pore structure, good conductivity, and stable electrochemical performance, but it can also increase the conductivity and additional active sites of carbonaceous materials through self-doping effects (e.g., nitrogen, sulfur, phosphorus). In particular, biomass-derived carbon loaded with corresponding metal nitrogen (sulfur, phosphorus) compounds can serve as excellent anode materials for secondary batteries. Simultaneously, the abundant sources of biomass raw materials, its environmental friendliness, and ease of processing and structural design make biomass carbon materials ideal candidate materials for secondary batteries.

[0005] CN115571879A describes a method for preparing active materials with energy storage structures and electrochemical properties by cultivating biomass in soil or wastewater contaminated with metal ions, followed by a series of post-treatments including drying, pre-oxidation, activation, and carbonization. However, this method has limited adsorption capacity for pollutants, lacks assessment of purification capabilities, and has a relatively long enrichment period for metal elements (7-90 days). In the process of converting biomass into energy storage carbon materials, the use of traditional pore-forming agents to prepare porous carbon is cumbersome, and the conversion of heavy metal elements into metal nitrides relies on an external nitrogen source, increasing preparation costs. Furthermore, the types of metal compounds presented are limited, lacking adaptability to different directions in the energy storage field.

[0006] CN104084221A utilizes biosorption technology to adsorb and enrich heavy metal ions from industrial wastewater onto biomass powder particles. Then, the biomass powder loaded with heavy metal ions is combined with sulfur-containing... 2- Se 2- The method involves contacting reagents (sodium sulfide, sodium hydrosulfide, thiourea, hydrogen sulfide, or sodium selenide, sodium selenide, selenurea, hydrogen selenide, etc.) to convert heavy metal ions adsorbed on biomass powder particles into corresponding metal sulfides (selenides) for use in photocatalysis. However, this method requires a large amount of highly polluting and toxic chemical reagents during preparation, and necessitates additional alkaline washing of the biomass, increasing the complexity and hazard of the process. Furthermore, experimental verification of the biomass' ability to adsorb heavy metals is lacking.

[0007] Therefore, exploring a low-cost, simple, and easily scalable method to achieve the controllable preparation of carbon materials for energy storage remains a major challenge in the field of energy storage material preparation. Summary of the Invention

[0008] The purpose of this invention is to overcome the problems existing in the prior art and to provide an energy storage carbon material, its preparation method, and its application.

[0009] Based on the concept of waste-to-waste treatment, this invention utilizes biomass waste to adsorb metal ions while simultaneously carbonizing the hazardous solid waste adsorbent used in the adsorption process. This allows the metal ions adsorbed on the biomass particles to react with the sulfur (phosphorus, nitrogen) functional groups of the biomass itself, being converted in situ into corresponding metal sulfides (phosphorus, nitrogen) compounds, which can then be used as energy storage materials for secondary batteries. Unlike other metal compound composite materials, which use large amounts of chemical reagents in their preparation, resulting in complex processes and cumbersome procedures that can easily pollute the environment, this invention is expected to find widespread application in the preparation of low-cost, high-performance battery materials.

[0010] To achieve the above objectives, the first aspect of the present invention provides a method for preparing an energy storage carbon material, wherein the method includes: carbonizing biomass waste enriched with metal ions to obtain an energy storage carbon material.

[0011] The method of this invention can transform various valuable heavy metal ions in industrial wastewater from a waste state into a high-quality raw material source for the production of secondary battery energy storage materials.

[0012] A second aspect of the present invention provides an energy storage carbon material prepared according to the method described in the first aspect.

[0013] A third aspect of the present invention provides the application of the energy storage carbon material according to the second aspect in the preparation of secondary metal / ion batteries.

[0014] A fourth aspect of the present invention provides a secondary metal / ion battery, wherein the battery uses the energy storage carbon material described in the second aspect as the negative electrode material.

[0015] The beneficial technical effects achieved by the present invention through the above technical solution are as follows:

[0016] (1) This invention transforms biomass waste enriched with metal ions into energy storage carbon materials with outstanding metal affinity through one-step carbonization. It makes full use of the sulfur, phosphorus, nitrogen and other elements in the biomass itself, and can successfully prepare metal compounds without the need for additional chemical reagents. This greatly simplifies the process and avoids the problem of secondary pollution from high-risk chemicals.

[0017] (2) The energy storage carbon material prepared by the present invention can promote the uniform deposition of metals during charging and discharging, and avoid safety problems caused by dendrite growth. At the same time, metal ions in industrial wastewater can be used to prepare high-value-added secondary battery energy storage materials by means of the simple and low-cost method of bio-adsorption.

[0018] (3) The present invention can flexibly control the type of metal compound generated by adjusting the carbonization temperature. As the carbonization temperature increases, the adsorbed metal ions will be converted into metal nitrides, metal sulfides and metal phosphides in sequence. At higher temperatures, the metal compounds will be reduced and volatilized. The remaining part is doped into carbon in the form of single atoms or nanoclusters, and the pores left by volatilization make the material form a porous carbon structure. Attached Figure Description

[0019] Figure 1 This is the result of the adsorption kinetics test of cadmium ions on rapeseed meal waste in Example 1 of the present invention.

[0020] Figure 2 This is the result of the adsorption isotherm test of cadmium ions on rapeseed meal waste in Example 1 of the present invention.

[0021] Figure 3 This is a transmission electron microscope (TEM) image of the energy storage carbon material prepared in Example 1 of this invention.

[0022] Figure 4 This is the XRD pattern of the energy storage carbon material prepared in Example 1 of the present invention.

[0023] Figure 5 This is the Raman spectrum of the energy storage carbon material prepared in Example 1 of this invention.

[0024] Figure 6 This is the overall X-ray photoelectron spectrum of the energy storage carbon material prepared in Example 1 of the present invention.

[0025] Figure 7 This is a high-resolution spectrum of the S element in the energy storage carbon material prepared in Example 1 of this invention.

[0026] Figure 8 This is a high-resolution Cd element spectrum of the energy storage carbon material prepared in Example 1 of this invention.

[0027] Figure 9 This is a coulombic efficiency test chart of the energy storage carbon material prepared in Example 1 of the present invention as a sodium metal anode modification material in a button-type half-cell.

[0028] Figure 10 This is a cycle stability test diagram of the energy storage carbon material prepared in Example 1 of the present invention as a modified material for sodium metal batteries in a symmetrical battery.

[0029] Figure 11 This is a rate performance test diagram of the energy storage carbon material prepared in Example 1 of the present invention as a modified material for sodium metal batteries in a full cell.

[0030] Figure 12 This is a test graph showing the long-cycle performance of the energy storage carbon material prepared in Example 1 of this invention as a modified material for sodium metal batteries in a full cell.

[0031] Figure 13 This is a transmission electron microscope (TEM) image of the energy storage carbon material prepared in Example 10 of the present invention. Detailed Implementation

[0032] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0033] The first aspect of the present invention provides a method for preparing an energy storage carbon material, wherein the method includes: carbonizing biomass waste enriched with metal ions to obtain an energy storage carbon material.

[0034] The key technical problem this invention aims to solve is to change the current situation where secondary pollution occurs during the post-treatment of highly toxic heavy metal ion adsorbents (using agricultural and forestry waste as raw materials) in traditional industrial wastewater treatment, while simultaneously overcoming the problems of low capacity, slow ion transport, uneven metal deposition, dendrite growth, and volume expansion of existing secondary battery anode materials. This invention combines the removal of valuable metal ions from wastewater with the preparation and production of high-value-added energy storage materials. It fully utilizes the active functional groups of biomass itself and its impurities such as sulfur, phosphorus, and nitrogen to convert highly toxic heavy metal ions in situ into uniformly dispersed metal compound nanoparticles within biomass carbon.

[0035] During the charging and discharging process of secondary metal / ion batteries, the introduction of metal compound nanoparticles can not only provide additional nucleation sites, but also effectively reduce the diffusion barrier of ions on the electrode surface, accelerate ion transport and desolvation processes, and greatly improve the specific capacity and fast charging performance of the battery. This is of great significance for realizing the preparation of low-cost, high-performance secondary battery anode materials and thus promoting the large-scale application of secondary batteries.

[0036] In some embodiments of the present invention, the metal ion is selected from at least one of magnesium ion, calcium ion, chromium ion, manganese ion, iron ion, cobalt ion, nickel ion, copper ion, zinc ion, lead ion and cadmium ion.

[0037] In some embodiments of the invention, the carbonization is carried out under a protective atmosphere.

[0038] In some embodiments of the present invention, the protective atmosphere is an argon or nitrogen atmosphere.

[0039] In some embodiments of the present invention, the carbonization process includes: heating to 100-300°C (carbonization temperature) at a heating rate of 1-20°C / min and holding at that temperature for 0.5-2 hours, and then heating to 400-2000°C at the same heating rate and holding at that temperature for 1-3 hours.

[0040] In some embodiments of the present invention, the carbonization process includes: heating to 150°C at a heating rate of 2.5°C / min and holding at that temperature for 30 min; then heating to 600°C (carbonization temperature) at the same heating rate and holding at that temperature for 1 h.

[0041] This invention allows for controllable adjustment of the types of metal compounds generated by adjusting the carbonization temperature, thereby adapting to the performance requirements of energy storage carbon materials in different application scenarios.

[0042] For example, metal oxides have advantages such as high specific capacitance, high conductivity, high natural abundance, diverse valence states, and ease of design and manufacturing. Therefore, they are widely used in supercapacitor electrode materials. However, their main disadvantages are short cycle life and a large gap between actual and theoretical capacitance.

[0043] Metal sulfides have been widely studied due to their advantages such as good conductivity, low cost, low electronegativity, good semiconductor properties, and good redox reactivity. Because the electronegativity of sulfur atoms is weaker than that of oxygen atoms, metal sulfides exhibit higher conductivity, thermal stability, mechanical stability, and electrochemical performance than their corresponding metal oxides under the same conditions. However, they are very prone to aggregation during frequent charging and discharging, leading to a decrease in capacity. Furthermore, fluctuations, expansion, thermodynamic instability, acid oxidation, and volatility are common problems in practical market applications of metal sulfides.

[0044] Metal phosphides possess metalloid properties, abundant redox reaction sites, and excellent electrical conductivity. Due to the large radius of phosphorus atoms, phosphides exhibit a variety of crystal structures. Furthermore, phosphorus's low electronegativity ensures rapid charge transfer. Compared to metal oxides, metal phosphides are advantageous for rapid electron transport in high-power-density energy storage devices. However, their preparation often involves multiple phase components, making the synthesis of pure transition metal phosphides challenging.

[0045] This invention enables controllable adjustment of the types of metal compounds through a simple preparation method, providing a new approach for the preparation of future high-performance electrode materials.

[0046] In some embodiments of the present invention, the energy storage carbon material is a carbon material loaded with metal compound nanoparticles.

[0047] In some embodiments of the present invention, the metal compound is selected from at least one of magnesium oxide, magnesium sulfide, chromium oxide, chromium sulfide, manganese oxide, manganese sulfide, iron oxide, iron phosphide, iron sulfide, cobalt oxide, cobalt phosphide, cobalt sulfide, nickel oxide, nickel sulfide, nickel phosphide, nickel nitride, copper oxide, copper sulfide, copper phosphide, zinc oxide, zinc sulfide, zinc phosphide, cadmium oxide, cadmium sulfide, cadmium phosphide, and other metal compounds of the same group.

[0048] In some embodiments of the present invention, the biomass waste enriched with metal ions is obtained by the following method: the biomass waste is crushed, washed and dried, added to wastewater containing metal ions for adsorption, and after adsorption is completed, it is centrifuged and filtered to obtain the biomass waste enriched with metal ions.

[0049] In this invention, the metal ion-containing wastewater can be either simulated metal ion wastewater prepared in the laboratory or actual industrial wastewater containing metal ions obtained by sampling from relevant industrial sites.

[0050] This invention uses natural biomass waste as a metal ion adsorbent, eliminating the need for additional chemical treatment of the biomass. It utilizes the abundant active groups of the plant itself as adsorption sites, and the inherent capillary action and concentration gradient of the system enable the metal ions to be uniformly adsorbed within the biomass. The process is short, low-cost, and simple.

[0051] In this invention, magnetic stirring or a temperature-controlled shaker is used during the adsorption process. After adsorption is complete, centrifugal filtration is performed, and the biomass waste is collected and dried in a forced-air drying oven for 24 hours.

[0052] In some embodiments of the present invention, the biomass waste contains active functional groups such as S-glycoside, -SH, -NH2, PO, -OH or -COOH.

[0053] In some embodiments of the present invention, the biomass waste is selected from at least one of rapeseed meal, sugarcane bagasse, and soybean meal.

[0054] In some embodiments of the present invention, the pH value of the wastewater containing metal ions is 2-12, preferably 5-7.

[0055] In some embodiments of the present invention, the amount of biomass waste added is 0.1-100 g / L, preferably 1-20 g / L.

[0056] In some embodiments of the present invention, the adsorption time is 10-2000 min, preferably 500-1500 min.

[0057] A second aspect of the present invention provides an energy storage carbon material prepared according to the method described in the first aspect.

[0058] A third aspect of the present invention provides the application of the energy storage carbon material according to the second aspect in the preparation of secondary metal / ion batteries.

[0059] A fourth aspect of the present invention provides a secondary metal / ion battery, wherein the battery uses the energy storage carbon material described in the second aspect as the negative electrode material.

[0060] This invention utilizes biological waste to efficiently purify industrial wastewater while simultaneously preparing energy storage carbon materials loaded with metal compounds through a one-step carbonization process. The entire process requires no additional chemical reagents, maximizing the green and environmentally friendly nature of the preparation. Furthermore, the type of metal compound can be controlled by adjusting the carbonization temperature. This invention combines the utilization of biomass resources, the purification of heavy metal pollutants, and the recycling of waste adsorbents. Its application in lithium-ion and sodium-ion secondary batteries induces uniform nucleation of metal ions on their surfaces, promoting smooth metal deposition and exhibiting high energy density and excellent cycle performance.

[0061] The present invention will be described in detail below through embodiments.

[0062] Unless otherwise specified in the following examples and comparative examples, all conditions were performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available products.

[0063] Example 1

[0064] This embodiment illustrates a method for preparing energy storage carbon materials using rapeseed meal as raw material.

[0065] Add 50 mL of 0.2 g / L Cd to a centrifuge tube. 2+ Add 0.1 g of rapeseed meal to the solution and place it in a constant temperature shaker (25℃, 150 r / min). After shaking and adsorption for 600 min, filter and collect the rapeseed meal, then dry it thoroughly in a forced-air drying oven. Transfer the dried rapeseed meal to a tube furnace and heat it to 100℃ at a rate of 5℃ / min under an argon atmosphere, holding it at that temperature for 30 min. Then, heat it to 600℃ at the same rate and hold it for 1 h. After cooling to room temperature, the energy storage carbon material loaded with cadmium sulfide nanoparticles is obtained.

[0066] Figures 3-8 The prepared energy storage carbon material was characterized.

[0067] Example 2

[0068] This embodiment illustrates a method for preparing energy storage carbon materials using sugarcane bagasse as raw material.

[0069] Add 50 mL of 0.2 g / L Cd to a centrifuge tube. 2+ Add 0.1 g of sugarcane bagasse to the solution and place it in a constant temperature shaker (25℃, 150 r / min). After shaking and adsorption for 600 min, filter and collect the sugarcane bagasse, then thoroughly dry it in a forced-air drying oven. Transfer the dried sugarcane bagasse to a tube furnace and heat it to 100℃ at a rate of 5℃ / min under an argon atmosphere, holding it at that temperature for 30 min. Then, heat it to 600℃ at the same rate and hold it for 1 h. After cooling to room temperature, the energy storage carbon material is obtained.

[0070] Example 3

[0071] This embodiment illustrates a method for preparing energy storage carbon materials using soybean meal as raw material.

[0072] Add 50 mL of 0.2 g / L Cd to a centrifuge tube. 2+Add 0.1g of soybean meal to the solution and place it in a constant temperature shaker (25℃, 150r / min). After shaking and adsorption for 600min, filter and collect the soybean meal, then thoroughly dry it in a forced-air drying oven. Transfer the dried soybean meal to a tube furnace and heat it to 100℃ at a rate of 5℃ / min under an argon atmosphere, holding it at that temperature for 30min. Then, heat it to 600℃ at the same rate and hold it for 1h. After cooling to room temperature, the energy storage carbon material is obtained.

[0073] Example 4

[0074] This embodiment illustrates a method for preparing energy storage carbon materials.

[0075] Add 50 mL of 0.2 g / L Zn to a centrifuge tube. 2+ Add 0.1g of rapeseed meal to the solution and place it in a constant temperature shaker (25℃, 150r / min). After shaking and adsorption for 600min, filter and collect the rapeseed meal, then dry it thoroughly in a forced-air drying oven. Transfer the dried rapeseed meal to a tube furnace and heat it to 100℃ at a rate of 5℃ / min under an argon atmosphere, holding it at that temperature for 30min. Then, heat it to 600℃ at the same rate and hold it for 1h. After cooling to room temperature, the energy storage carbon material is obtained.

[0076] Example 5

[0077] This embodiment illustrates a method for preparing energy storage carbon materials.

[0078] Add 50 mL of Ni solution with a concentration of 0.2 g / L to the centrifuge tube. 2+ Add 0.1g of rapeseed meal to the solution and place it in a constant temperature shaker (25℃, 150r / min). After shaking and adsorption for 600min, filter and collect the rapeseed meal, then dry it thoroughly in a forced-air drying oven. Transfer the dried rapeseed meal to a tube furnace and heat it to 100℃ at a rate of 5℃ / min under an argon atmosphere, holding it at that temperature for 30min. Then, heat it to 600℃ at the same rate and hold it for 1h. After cooling to room temperature, the energy storage carbon material is obtained.

[0079] Example 6

[0080] This embodiment illustrates a method for preparing energy storage carbon materials.

[0081] Wastewater discharged from a cadmium electroplating workshop was collected, and the cadmium ion content was measured to be 0.11 g / L. After adjusting the pH of the solution to 7.0, 50 mL of the above solution was added to a centrifuge tube, along with 0.1 g of rapeseed meal. The mixture was placed in a constant temperature shaker (25℃, 150 r / min) and shaken for 600 min for adsorption. The rapeseed meal was then filtered and collected, and thoroughly dried in a forced-air drying oven. The dried sample was then transferred to a tube furnace and heated to 100℃ at a rate of 5℃ / min under an argon atmosphere, and held for 30 min. The temperature was then increased to 600℃ at the same rate and held for 1 h. The energy storage carbon material was obtained after cooling to room temperature.

[0082] Example 7

[0083] This embodiment illustrates a method for preparing energy storage carbon materials.

[0084] Add 50 mL of 0.2 g / L Cd to a centrifuge tube. 2+ Add 0.1g of rapeseed meal to the solution, stir and react for 600min, then filter and collect the rapeseed meal, thoroughly dry it in a forced-air drying oven, and transfer the dried rapeseed meal to a tube furnace. Under an argon atmosphere, heat to 100℃ at a heating rate of 5℃ / min and hold for 30min; then heat to 600℃ at the same heating rate and hold for 1h. The energy storage carbon material is obtained after cooling to room temperature.

[0085] Example 8

[0086] This embodiment illustrates a method for preparing energy storage carbon materials.

[0087] Add 50 mL of Ni solution with a concentration of 0.2 g / L to the centrifuge tube. 2+ Add 0.1g of rapeseed meal to the solution and place it in a constant temperature shaker (25℃, 150r / min). After shaking and adsorption for 600min, filter and collect the rapeseed meal, and dry it thoroughly in a forced-air drying oven. After drying, transfer the rapeseed meal to a tube furnace and heat it to 100℃ at a heating rate of 5℃ / min under an argon atmosphere, and hold it for 30min. Then heat it to 700℃ at the same heating rate and hold it for 1h. When the temperature cools to room temperature, the energy storage carbon material loaded with nickel sulfide nanoparticles is obtained.

[0088] Example 9

[0089] This embodiment illustrates a method for preparing energy storage carbon materials.

[0090] Add 50 mL of 0.2 g / L Cd to a centrifuge tube. 2+Add 0.1g of rapeseed meal to the solution and place it in a constant temperature shaker (25℃, 150r / min). After shaking and adsorption for 600min, filter and collect the rapeseed meal, then thoroughly dry it in a forced-air drying oven. Transfer the dried rapeseed meal to a tube furnace and heat it to 100℃ at a rate of 5℃ / min under an argon atmosphere, holding it at that temperature for 30min. Then, heat it to 600℃ at the same rate and hold it for 3h. After cooling to room temperature, the energy storage carbon material is obtained.

[0091] Example 10

[0092] Energy storage carbon materials were prepared according to the method in Example 1, except that the carbonization temperature was adjusted from 600℃ to 900℃, resulting in cadmium-doped porous carbon energy storage materials. Its transmission electron microscopy image is shown below. Figure 13 As shown.

[0093] When the carbonization temperature is 900℃, cadmium sulfide undergoes a redox reaction with the carbon matrix, transforming into elemental cadmium which then volatilizes upon heating, leaving a porous structure in the carbon matrix. Some cadmium elements are incorporated into the carbon in the form of single atoms, providing reactivity for subsequent electrochemical processes.

[0094] Example 11

[0095] Energy storage carbon materials were prepared according to the method in Example 8, except that the carbonization temperature was adjusted from 700°C to 500°C to obtain energy storage carbon materials loaded with nickel oxide nanoparticles.

[0096] Example 12

[0097] Energy storage carbon materials were prepared according to the method in Example 8, except that the carbonization temperature was adjusted from 700°C to 1000°C to obtain energy storage carbon materials loaded with nickel phosphide nanoparticles.

[0098] Comparative Example 1

[0099] Add 50 mL of deionized water and 0.1 g of rapeseed meal to a centrifuge tube, place it in a constant temperature shaker (25℃, 150 r / min), shake for 600 min, then filter and collect the rapeseed meal. Dry it thoroughly in a forced-air drying oven. Transfer the dried rapeseed meal to a tube furnace and heat it to 100℃ at a rate of 5℃ / min under an argon atmosphere, holding for 30 min. Then heat it to 600℃ at the same rate and hold for 1 h. The plant carbon material is obtained after cooling to room temperature.

[0100] Test Example 1

[0101] (1) Add 50 mL of a series of Cd solutions to centrifuge tubes. 2+Add 0.1 g of rapeseed meal material to the solution and place it in a constant temperature shaker (25℃, 150 r / min). After shaking and adsorption for the corresponding time, centrifuge and collect the supernatant. ICP-MS is used to determine the residual amount of heavy metal ions after adsorption. The adsorption kinetics and adsorption isotherm results are as follows: Figure 1 and Figure 2 As shown.

[0102] (2) The adsorption capacity of different biomass wastes in Examples 1-3 was verified, and the results are shown in Table 1 and Table 2.

[0103] Table 1 Effects of different biomass wastes on Cd 2+ Adsorption kinetics experimental results

[0104]

[0105]

[0106] Table 2 Effects of different biomass wastes on Cd 2+ Adsorption isotherm test results

[0107]

[0108] Table 1 shows the changes in adsorption capacity with adsorption time, indicating that the three types of biomass wastes have varying effects on Cd. 2+ The adsorption rates were all rapid, reaching adsorption equilibrium within 240 minutes, with adsorption capacities all exceeding 18 mg / g, indicating considerable adsorption capacity. Table 2 shows that the adsorption capacity of different biomass samples increased with increasing metal ion concentration in the solution, eventually reaching adsorption equilibrium.

[0109] (3) The adsorption capacity of rapeseed meal waste in Examples 4-6 for different types of metal ion solutions was evaluated.

[0110] Table 3 Adsorption capacity of rapeseed meal waste for different types of metal ion solutions

[0111]

[0112] Table 3 shows that rapeseed meal has a significant impact on Zn content in the initial stage. 2+ Ni 2+ Cd 2+ The adsorption capacity of the samples increased rapidly with time, indicating a fast adsorption rate, followed by a slower adsorption process, eventually reaching adsorption equilibrium (approximately 240 min). Furthermore, the adsorption capacity of rapeseed meal for different metal ions remained above 18 mg / g, demonstrating that the method of using biomass waste to adsorb metal ions in solution and provide a metal source for subsequent carbonization has a certain degree of universality.

[0113] Test Example 2

[0114] The energy storage carbon materials prepared in Examples 1-9 and the plant-based carbon materials prepared in Comparative Example 1 were mixed with a conductive agent and a binder at a mass ratio of 8:1:1, respectively. The conductive agent was acetylene black, and the binder was PVDF (polyvinylidene fluoride). Using NMP (N-methylpyrrolidone) as a solvent, the mixture was ground evenly in a mortar to obtain an electrode slurry. The slurry was then uniformly coated onto a copper foil and dried in a vacuum oven at 120°C for 24 hours. The copper foil coated with the active material was then pressed into a circular sheet with a diameter of 14 mm using a slicing machine, thus preparing the electrode sheet.

[0115] A CR2032 battery casing was selected, with a 14mm diameter sodium sheet as the negative electrode. Following this, a glass fiber separator, electrolyte, electrode sheets, gaskets, spring sheets, and the positive electrode casing were sequentially placed. Finally, the half-cell was assembled using a battery packaging machine. A button-type sodium metal half-cell was assembled using the energy storage carbon material obtained in Example 1 as the positive electrode, and its coulombic efficiency was tested. The test results are shown in the figure. Figure 9 As shown.

[0116] Two identical half-cells obtained in Example 1 were deposited with the same capacity of metallic sodium at the same current density. The cells were then disassembled to remove the pre-deposited sodium electrode sheets, which were used as electrodes for the symmetrical cells. A CR2032 battery case was used, and the assembly method was the same as that for the half-cells.

[0117] The half-cell using the electrode material obtained in Example 1 was deposited with a certain capacity of metallic sodium at a certain current density. The electrode sheet was then removed and used as the negative electrode of the full cell. Commercially available NVP (sodium vanadium phosphate) was used as the positive electrode. A CR2025 battery case was used, and the full cell was assembled following the same procedure as the half-cell. Rate performance and cycle performance were tested, and the test results are shown in the figure. Figure 11-12 As shown.

[0118] In the full-cell test, the voltage window was selected as 2.6-3.8V, and the current density for the rate test was selected as 0.1C, 0.2C, 0.5C, 1C, 2C, and 5C respectively. The test results are shown in Table 4.

[0119] Electrodes made from the energy storage carbon materials of Examples 2-9 and the plant carbon material of Comparative Example 1 were assembled with sodium sheets to form button-type sodium metal half-cells, and the test conditions were the same as those described above.

[0120] Comparative Example 2: The electrode coated with the active material was replaced with pure copper foil with a diameter of 14 mm. Button-type sodium metal half-cells and full cells were assembled and tested according to the same experimental procedure as above.

[0121] All assembled batteries were left to stand in an open circuit at room temperature for 12 hours before electrochemical testing.

[0122] Table 4. Test Results of Button-Type Sodium Metal Full Cells

[0123]

[0124]

[0125] As shown in Table 4, the energy storage carbon materials prepared in Examples 1-9 have significant advantages in modifying sodium metal anodes. At a current density of 0.1C, the specific capacity of these batteries is consistently higher than that at 100 mAh g⁻¹. -1 Even when the current density increases to 5C, the specific capacity remains at 70 mAh g. -1 The above demonstrates excellent rate capability, significantly outperforming the pure plant carbon material of Comparative Example 1 and the pure copper foil of Comparative Example 2.

[0126] When the energy storage carbon materials prepared in Examples 1-9 are used as modifying materials for sodium metal batteries, at 1 mA cm⁻¹... -2 0.5mAh cm -2 The coulombic efficiency was tested in a coin cell under the specified test conditions; a 3mAh cm⁻¹ electrode was deposited on the electrode surface. -2 Sodium is used as an electrode in a symmetrical cell to assemble a symmetrical cell at 1 mA cm⁻¹. -2 0.5mAh cm -2 Cyclic performance was tested under the specified test conditions. The results are shown in Table 5.

[0127] Table 5 Results of sodium deposition stripping test

[0128]

[0129]

[0130] The results above clearly show that the energy storage carbon materials in Examples 1-9 achieve a performance of 1 mA cm⁻¹. -2 0.5mAh cm -2 Under the conditions described above, the cells can achieve stable cycling for more than 1000 cycles with high coulombic efficiency. Furthermore, the symmetric cells assembled using the above materials can maintain a relatively stable voltage after 500 hours of cycling. The cell performance is significantly better than that of the pure plant carbon material in Comparative Example 1 and the pure copper foil current collector in Comparative Example 2.

[0131] Test Example 3

[0132] The energy storage carbon materials prepared in Examples 1-9 and the plant-based carbon materials prepared in Comparative Example 1 were mixed with a conductive agent and a binder at a mass ratio of 8:1:1, respectively. The conductive agent was acetylene black, and the binder was PVDF (polyvinylidene fluoride). Using NMP (N-methylpyrrolidone) as a solvent, the mixture was ground evenly in a mortar to obtain an electrode slurry. The slurry was then uniformly coated onto a copper foil and dried in a vacuum oven at 120°C for 24 hours. The copper foil coated with the active material was then pressed into a circular sheet with a diameter of 14 mm using a slicing machine, thus preparing the electrode sheet.

[0133] A CR2032 battery casing was selected, with a 14mm diameter lithium sheet as the negative electrode. Following this, a glass fiber separator, electrolyte, electrode plates, gaskets, spring plates, and the positive electrode casing were sequentially added. Finally, a battery packaging machine was used to assemble the components to obtain a half-cell, and its coulombic efficiency was tested.

[0134] Two identical half-cells obtained in Examples 1-9 were deposited with the same capacity of metallic lithium at the same current density. The cells were then disassembled to remove the pre-deposited lithium electrode sheets, which were used as electrodes for the symmetrical cells. The cells were assembled using a CR2032 battery case in the same way as the half-cells.

[0135] Half-cells with electrode materials obtained in Examples 1-9 were deposited with a certain capacity of metallic lithium at a certain current density. The electrode sheets were then removed and used as the negative electrode of the full cell. Commercial LFP (lithium iron phosphate) was used as the positive electrode. A CR2025 battery case was used, and the full cell was assembled according to the same procedure as the half-cell. The rate performance and cycle performance were then tested.

[0136] Comparative Examples 1 and 2 were pure plant-based carbon and pure copper foil, respectively. The testing procedures were the same as those in Examples 1-9 above.

[0137] All assembled batteries were left to stand in an open circuit at room temperature for 12 hours before electrochemical testing.

[0138] In the full-cell test, the voltage window was selected as 2.8-4.2V, and the current density for the rate test was selected as 0.5C, 1C, 2C, 5C, 10C, and 20C respectively. The test results are shown in Table 6.

[0139] Table 6. Test Results of Button-Type Lithium Metal Full Batteries

[0140]

[0141]

[0142] As shown in Table 6, when lithium metal anodes modified with carbon storage materials prepared in Examples 1-9 are used, the specific capacity of the full cell remains at 100 mAh g⁻¹ at a current density of 0.5C. -1The above values ​​are still present, and even at 20C, the specific capacity remains at 37-69mAh g. -1 The rate performance is significantly better than that of the pure plant carbon material in Comparative Example 1 and the pure copper foil in Comparative Example 2.

[0143] When the energy storage carbon materials prepared in Examples 1-9 are used as modifying materials for lithium metal batteries, at 1 mA cm⁻¹ -2 0.5mAh cm -2 The coulombic efficiency was tested in a coin cell under the specified test conditions; a 3mAh cm⁻¹ electrode was deposited on the electrode surface. -2 Lithium is used as an electrode in a symmetrical battery to assemble a symmetrical battery, at 1 mA cm⁻¹. -2 0.5mAh cm -2 Cyclic performance was tested under the specified test conditions. The results are shown in Table 7.

[0144] Table 7. Test results of lithium deposition stripping test

[0145]

[0146]

[0147] The test results above show that at 1mA cm -2 0.5mAh cm -2 Under the test conditions, it can still maintain a coulombic efficiency of over 97% after 500 cycles. The assembled symmetrical cell can still maintain a stable voltage after 300 hours of cycling, showing good long-cycle performance. Its performance is significantly better than that of the pure plant carbon material in Comparative Example 1 and the pure copper foil in Comparative Example 2.

[0148] Test Example 4

[0149] The energy storage carbon materials prepared in Examples 1-9 and the plant-based carbon materials prepared in Comparative Example 1 were mixed with a conductive agent and a binder at a mass ratio of 8:1:1, respectively. The conductive agent was acetylene black, and the binder was PVDF (polyvinylidene fluoride). Using NMP (N-methylpyrrolidone) as a solvent, the mixture was ground evenly in a mortar to obtain an electrode slurry. The slurry was then uniformly coated onto a copper foil and dried in a vacuum oven at 120°C for 24 hours. The copper foil coated with the active material was then pressed into a circular sheet with a diameter of 14 mm using a slicing machine, thus preparing the electrode sheet.

[0150] A CR2032 battery casing was selected, with a 10mm diameter zinc sheet as the negative electrode. Following this, a glass fiber separator, electrolyte, electrode plates, gaskets, spring plates, and the positive electrode casing were sequentially placed. Finally, a battery packaging machine was used to assemble the components to obtain a half-cell, and its coulombic efficiency was tested.

[0151] Two identical half-cells obtained in Examples 1-9 were deposited with the same capacity of metallic zinc at the same current density. The cells were then disassembled to remove the pre-deposited zinc electrode sheets, which were used as electrodes for the symmetrical cells. A CR2032 battery case was used, and the assembly method was the same as that for the half-cells.

[0152] Half-cells using electrode materials obtained in Examples 1-9 were deposited with a certain capacity of metallic zinc at a certain current density. The electrode sheets were then removed and used as the negative electrode of the full cell. Commercial manganese dioxide was used as the positive electrode. The full cell was assembled using a CR2025 battery case and the same procedure as the half-cell was followed. The rate performance and cycle performance were then tested.

[0153] Comparative Examples 1 and 2 were pure plant-based carbon and pure copper foil, respectively. The testing procedures were the same as those in Examples 1-9 above.

[0154] All assembled batteries were left to stand in an open circuit at room temperature for 12 hours before electrochemical testing.

[0155] In the full-cell test, the voltage window was selected as 1.0-3.8V, and the current density for the rate test was selected as 0.2C, 0.5C, 1C, 2C, and 5C respectively. The test results are shown in Table 9.

[0156] Table 8. Test Results of Button-Type Zinc Metal Full Cells

[0157]

[0158]

[0159] As shown in Table 8, when the zinc metal anodes modified with energy storage carbon materials prepared in Examples 1-9 are used, the specific capacity of the full cell remains at 120 mAh g⁻¹ at a current density of 5C. -1 In summary, the rate performance is significantly better than that of the pure plant carbon material in Comparative Example 1 and the pure copper foil in Comparative Example 2.

[0160] When the energy storage carbon materials prepared in Examples 1-9 are used as modifying materials for zinc metal batteries, at 1 mA cm⁻¹ -2 0.5mAh cm -2 The coulombic efficiency was tested in a coin cell under the specified test conditions; a 3mAh cm⁻¹ electrode was deposited on the electrode surface. -2 Zinc was used as an electrode in a symmetrical cell to assemble a symmetrical cell at 1 mA cm⁻¹. -2 0.5mAh cm -2 Cyclic performance was tested under the specified test conditions. The results are shown in Table 9.

[0161] Table 9. Zinc Deposition Stripping Test Results

[0162]

[0163]

[0164] The test results above show that at 1mA cm -2 0.5mAh cm -2 Under the test conditions, it can still maintain a coulombic efficiency of over 90% after 500 cycles. The assembled symmetrical battery can still maintain a stable voltage after 300 hours of cycling, showing good long-cycle performance. Its performance is significantly better than that of the pure plant carbon material in Comparative Example 1 and the pure copper foil in Comparative Example 2.

[0165] Therefore, compared with the electrode materials currently reported, the material prepared by this method exhibits higher capacity and cycling stability.

[0166] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing an energy storage carbon material, characterized in that, The method includes: carbonizing biomass waste enriched with metal ions to obtain energy storage carbon materials; The metal ion is selected from at least one of nickel ion, zinc ion and cadmium ion; The biomass waste is selected from at least one of rapeseed meal, sugarcane bagasse and soybean meal; The carbonization process includes: heating to 100-300℃ at a heating rate of 1-20℃ / min and holding at that temperature for 0.5-2h, and then heating to 400-2000℃ at the same heating rate and holding at that temperature for 1-3h. The energy storage carbon material is a carbon material loaded with metal compound nanoparticles; the metal compound is selected from at least one of nickel oxide, nickel sulfide, nickel phosphide, nickel nitride, zinc oxide, zinc sulfide, zinc phosphide, cadmium oxide, cadmium sulfide, and cadmium phosphide.

2. The method according to claim 1, wherein, The carbonization is carried out under a protective atmosphere.

3. The method according to claim 2, wherein, The protective atmosphere is an argon or nitrogen atmosphere.

4. The method according to claim 1, wherein, The carbonization process includes: heating to 150°C at a heating rate of 2.5°C / min and holding at that temperature for 30 min; then heating to 600°C at the same heating rate and holding at that temperature for 1 h.

5. The method according to any one of claims 1-4, wherein, The biomass waste enriched with metal ions is obtained by the following method: the biomass waste is crushed, washed and dried, added to wastewater containing metal ions for adsorption, and after adsorption is completed, it is centrifuged and filtered to obtain the biomass waste enriched with metal ions.

6. The method according to any one of claims 1-4, wherein, The biomass waste contains active functional groups such as S-glycoside, -SH, -NH2, PO, -OH, or -COOH.

7. The method according to claim 5, wherein, The pH value of the wastewater containing metal ions is 2-12; And / or, the amount of biomass waste added is 0.1-100 g / L; And / or, the adsorption time is 10-2000 min.

8. The method according to claim 7, wherein, The pH value of the wastewater containing metal ions is 5-7; And / or, the amount of biomass waste added is 1-20 g / L; And / or, the adsorption time is 500-1500 min.

9. The method according to claim 7, wherein, The adsorption time was 600 min.

10. The energy storage carbon material prepared by the method according to any one of claims 1-9.

11. The application of the energy storage carbon material according to claim 10 in the preparation of secondary metal / ion batteries.

12. A secondary metal / ion battery, characterized in that, The battery uses the energy storage carbon material as described in claim 10 as the negative electrode material.

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