Preparation method of biomass hard carbon negative electrode material of sodium ion battery

Abstract

The application belongs to the technical field of sodium ion battery negative electrode materials, and discloses a preparation method of a sodium ion battery biomass hard carbon negative electrode material, wherein insect feed raw materials are mixed with zinc gluconate to feed insects, and the insect manure is collected for low-temperature pre-carbonization, and the product after pre-carbonization is subjected to acid pickling and drying, and then high-temperature carbonization to prepare a hard carbon material. The green and environment-friendly sodium ion battery biomass hard carbon negative electrode material preparation method has the characteristics of mass production, various surface morphologies of the hard carbon and excellent electrochemical performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of sodium ion battery negative electrode materials, and relates to a method for preparing a biomass hard carbon negative electrode material for a sodium ion battery. Specifically, the present invention relates to a method for preparing a biomass hard carbon negative electrode material for a sodium ion battery by using the feces of insects fed with a controlled ratio of feed ingredients as raw materials. Background Art

[0002] With the continuous growth of global energy demand and the increasingly severe environmental problems, the development of efficient and sustainable energy storage technology has become an important direction of current scientific research. As the most widely used energy storage device, lithium-ion batteries have gained a huge market share in the fields of consumer electronics, electric vehicles, etc. due to their excellent energy density and cycle performance. However, the limited lithium resources, price fluctuations and their environmental impact have prompted the research and development of sodium-ion batteries as an alternative. Sodium is highly abundant in the earth's crust, is inexpensive and environmentally friendly, so sodium-ion batteries are regarded as potential candidates for future energy storage technologies. Biomass hard carbon is one of the candidates for sodium-ion battery negative electrode materials because of its low cost. However, there are very few studies on the treatment of hard carbon surface structure. Therefore, the present invention uses the feces of insects fed with controlled feed ingredients as raw materials to prepare sodium-ion battery biomass hard carbon negative electrode materials with excellent electrochemical properties and controllable surface morphology, and has great commercial potential. Summary of the Invention

[0003] The present invention aims to improve the existing process and provide a new method for preparing sodium ion battery biomass hard carbon negative electrode material by using the excrement of insects fed with a controlled ratio of feed ingredients as raw materials at low cost and easy to industrialize.

[0004] This invention uses corn flour and zinc gluconate as feed, controlling the ratio of the feed ingredients, and collects waste excrement from insect farming to prepare the biomass hard carbon anode material. Because insect excrement is a byproduct of insect farming, this method offers the significant advantage of very low manufacturing costs. Furthermore, the surface morphology of the hard carbon can be controlled by adjusting the amount of zinc gluconate added, resulting in a controllable surface morphology.

[0005] The technical solution of the present invention is described in detail below.

[0006] A method for preparing a biomass hard carbon negative electrode material for a sodium ion battery, wherein the method uses the feces of insects fed with a controlled ratio of feed ingredients as raw material to prepare the biomass hard carbon negative electrode material for a sodium ion battery. The specific preparation method comprises the following steps:

[0007] S1. Feeding insects with feed, and then collecting insect feces; the feed includes insect feed raw materials and zinc gluconate;

[0008] S2, pre-carbonizing the collected insect feces at low temperature under inert gas;

[0009] S3. After carbonization, the product is collected, acid-washed, and dried, and then carbonized at high temperature under an inert gas to obtain a hard carbon material.

[0010] The present invention uses zinc gluconate as a feed additive to feed insects, which enables the insects to ingest zinc and excrete it with feces. Subsequently, zinc oxide is generated under the action of pre-carbonization to serve as a pore-forming agent, making it easy to obtain a porous hard carbon material. The surface structure of the hard carbon material can be controlled by controlling the conditions.

[0011] Preferably, the insect feed raw material in step S1 is corn flour. By using corn flour as the feed raw material, the insects mentioned in the present invention have better palatability and can further ensure that the insects eat it cleanly, thereby ensuring that the collected insect feces are not mixed with the feed.

[0012] Preferably, in step S1 , the feed is mixed with water into a ball and then fed, which is more conducive to uniformly mixing the insect feed raw materials and zinc gluconate and ensuring that all insects can eat them.

[0013] Preferably, the mass ratio of the insect feed raw material to zinc gluconate in step S1 is 100:(2.5-30). More preferably, the mass ratio of corn flour to zinc gluconate is 100:10.

[0014] Preferably, the insects in step S1 include but are not limited to at least one of mealworms, wax moth larvae, locusts, crickets, black soldier fly larvae, cockroaches, etc. More preferably, the experimental insects in step S1 are cockroaches.

[0015] Preferably, the low-temperature pre-carbonization temperature in step S2 is 400-700°C, the heating rate is 1-10°C / min, and the holding time is 0.5-4 hours. More preferably, the pre-carbonization temperature in step S2 is 600°C, the temperature is kept for 2 hours, and the heating rate is 5°C / min. Pre-carbonization allows the zinc in insect feces to generate zinc oxide inside and on the surface of the carbon at this temperature, thereby preparing in advance for the next step of generating porous hard carbon. The temperature, rate, and time will affect the amount and size of zinc oxide. Under the conditions of the present invention, a suitable product can be obtained, thereby having better performance.

[0016] Preferably, the inert atmosphere in step S2 and step S3 is at least one of nitrogen, helium and argon.

[0017] Preferably, the pickling in step S3 is performed with hydrochloric acid, the concentration of the hydrochloric acid is 0.5-5 mol / L, and the pickling time is 0.5-12 h; more preferably, the concentration is 1 mol / L, and the pickling time is 3 h.

[0018] Preferably, the acid washing in step S3 further includes water washing and filtration.

[0019] Preferably, the drying in step S3 is performed at 70°C.

[0020] Preferably, the high-temperature carbonization temperature in step S3 is 900-1600°C, the holding time is 0.5-4 hours, and the heating rate is 1-10°C / min. More preferably, the carbonization temperature in step S3 is 1400°C, the holding time is 2 hours, and the heating rate is 5°C / min. High-temperature carbonization conditions affect the properties of the hard carbon material, and the properties of the hard carbon material are better within the above range.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This invention provides a method for producing low-cost, surface-structure-controllable biomass hard carbon materials for sodium-ion batteries. The raw materials used in this method are derived from insect byproducts, resulting in extremely low cost. Furthermore, the surface structure of the hard carbon material can be controlled by controlling the zinc gluconate content in the feed, thereby meeting diverse application requirements. This environmentally friendly, highly cyclically stable method for preparing biomass hard carbon anode materials for sodium-ion batteries is characterized by large-scale production, diverse hard carbon surface morphologies, and excellent electrochemical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The X-ray diffraction patterns (XRD patterns) of the hard carbon materials prepared in Examples 1 and 2 are shown.

[0024] Figure 2 This is a scanning electron microscope (SEM) photograph of the hard carbon material prepared in Example 1.

[0025] Figure 3 This is a scanning electron microscope (SEM) photograph of the hard carbon material prepared in Example 2.

[0026] Figure 4 The cycling performance of the hard carbon materials prepared in Examples 1 and 2 at a current density of 0.05 A / g.

[0027] Figure 5 The cycling performance of the hard carbon materials prepared in Examples 1 and 2 at a current density of 1 A / g. DETAILED DESCRIPTION

[0028] In order to better clarify and understand the purpose, process scheme and advantages of the present invention, the technical scheme and implementation method of the present invention are further clearly, completely and in detail described below through specific examples and in combination with the accompanying drawings. It should be noted that the embodiments described in the present invention are implemented on the premise of the technical scheme of the present invention, and detailed implementation methods and specific operating processes are given, but they are only part of the embodiments of the present invention, not all of the embodiments. The specific implementation methods described are limited to illustrating and explaining the present invention and do not limit the present invention. Based on the embodiments in the present invention, all other implementation methods obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] Unless otherwise specified, the experimental methods and conditions used in the embodiments of the present invention are conventional methods and conventional conditions. The materials, reagents, or instruments used in the embodiments, unless otherwise specified, can be obtained from commercial sources or prepared by conventional methods. The reaction conditions embodied in the summary of the invention of the present invention are all capable of achieving the described reactions and obtaining products with the desired effects. Due to space limitations, some examples are listed below to further illustrate the advantages of the technical solutions of the present invention.

[0030] Example 1:

[0031] Corn flour and zinc gluconate were mixed in a ratio of 100:2.5, and a small amount of hot water was added to form a dough. This mixture was then fed to cockroaches. After the cockroaches consumed the food, the remaining feces were collected. The collected feces were pre-carbonized by heating to 600°C at 5°C / min under argon and holding for 2 hours. The carbonized product was collected, acid-washed with 1 mol / L hydrochloric acid for 2 hours, washed 3-4 times with ultrapure water, filtered, and finally dried at 70°C. The dried material was carbonized by heating to 1400°C at 5°C / min under argon and holding for 2 hours to obtain a hard carbon material. The specific surface area and pore volume of the material are shown in Table 1.

[0032] Example 2:

[0033] Corn flour and zinc gluconate were mixed in a ratio of 100:10, and a small amount of hot water was added to form a dough. This mixture was then fed to cockroaches. After the cockroaches had consumed the food, the remaining feces were collected. The collected feces were pre-carbonized by heating to 600°C at 5°C / min under argon and holding for 2 hours. The carbonized product was collected, acid-washed with 1 mol / L hydrochloric acid for 2 hours, washed 3-4 times with ultrapure water, filtered, and finally dried at 70°C. The dried material was carbonized by heating to 1400°C at 5°C / min under argon and holding for 2 hours to obtain a hard carbon material. The specific surface area and pore volume of the material are shown in Table 1.

[0034] Example 3:

[0035] Corn flour and zinc gluconate were mixed in a ratio of 100:30, and a small amount of hot water was added to form a dough. This mixture was then fed to cockroaches. After the cockroaches had consumed the food, the remaining feces were collected. The collected feces were pre-carbonized by heating to 600°C at 5°C / min under argon and holding the temperature for 2 hours. The carbonized product was collected, acid-washed with 1 mol / L hydrochloric acid for 2 hours, washed 3-4 times with ultrapure water, filtered, and finally dried at 70°C. The dried material was carbonized by heating to 1400°C at 5°C / min under argon and holding the temperature for 2 hours to obtain a hard carbon material. The specific surface area and pore volume of the material are shown in Table 1.

[0036] Example 4:

[0037] Corn flour and zinc gluconate were mixed in a ratio of 100:2.5, and a small amount of hot water was added to form a dough. The mixture was then fed to mealworms. After the mealworms consumed the meal, the remaining mealworm feces were collected. The collected mealworm feces were pre-carbonized by heating to 600°C at 5°C / min under argon and holding for 2 hours. The carbonized product was collected, acid-washed with 1 mol / L hydrochloric acid for 2 hours, washed 3-4 times with ultrapure water, filtered, and finally dried at 70°C. The dried material was carbonized by heating to 1400°C at 5°C / min under argon and holding for 2 hours to obtain a hard carbon material. The specific surface area and pore volume of the material are shown in Table 1.

[0038] Example 5:

[0039] Corn flour and zinc gluconate were mixed in a ratio of 100:15, and a small amount of hot water was added to form a dough. The mixture was then fed to black soldier fly larvae. After the larvae consumed the food, the remaining feces were collected. The collected feces were pre-carbonized by heating to 600°C at 5°C / min under argon and holding the temperature for 2 hours. The carbonized product was collected, acid-washed with 1 mol / L hydrochloric acid for 2 hours, washed 3-4 times with ultrapure water, filtered, and finally dried at 70°C. The dried material was carbonized by heating to 1400°C at 5°C / min under argon and holding the temperature for 2 hours to obtain a hard carbon material. The specific surface area and pore volume of the material are shown in Table 1.

[0040] Example 6:

[0041] Corn flour and zinc gluconate were mixed in a ratio of 100:5, and a small amount of hot water was added to form a dough. This mixture was then fed to locusts. After the locusts consumed the food, the remaining feces were collected. The collected feces were pre-carbonized by heating to 600°C at 5°C / min under argon and holding for 2 hours. The carbonized product was collected, acid-washed with 1 mol / L hydrochloric acid for 2 hours, washed 3-4 times with ultrapure water, filtered, and finally dried at 70°C. The dried material was carbonized by heating to 1400°C at 5°C / min under argon and holding for 2 hours to obtain a hard carbon material. The specific surface area and pore volume of the material are shown in Table 1.

[0042] Example 7:

[0043] Corn flour and zinc gluconate were mixed in a ratio of 100:5, and a small amount of hot water was added to form a dough. This mixture was then fed to Greater wax moth larvae. After the larvae consumed the food, the remaining feces were collected. The collected feces were pre-carbonized by heating to 600°C at 5°C / min under argon and holding for 2 hours. The carbonized product was collected, acid-washed with 1 mol / L hydrochloric acid for 2 hours, washed 3-4 times with ultrapure water, filtered, and finally dried at 70°C. The dried material was carbonized by heating to 1400°C at 5°C / min under argon and holding for 2 hours to obtain a hard carbon material. The specific surface area and pore volume of the material are shown in Table 1.

[0044] Table 1 Summary of specific surface area and pore volume of hard carbon materials in various examples

[0045]

[0046] From the above, it can be seen that the hard carbon prepared using cockroach feces in Examples 1-7 has a higher specific surface area and is the most preferred for insects. In Examples 1, 2, and 3, the more zinc gluconate is added, the larger the pore volume will be. The optimal zinc gluconate addition amount is 10%, which has the largest specific surface area and is the most preferred zinc gluconate addition amount.

[0047] The above-described embodiments are only preferred solutions of the present invention and are not intended to limit the present invention in any form. Other variations and modifications are possible without exceeding the technical solutions described in the claims.

Claims

1. A method for preparing a biomass hard carbon negative electrode material for a sodium ion battery, characterized in that: The following steps are involved: S1. Feeding insects with feed, and then collecting insect feces; the feed comprises an insect feed raw material and zinc gluconate, the mass ratio of the insect feed raw material to the zinc gluconate being 100:(2.5-30); the insect feed raw material is corn flour; and the insects are selected from at least one of mealworms, greater wax moth larvae, locusts, crickets, black soldier fly larvae, and cockroaches; S2. Pre-carbonizing the collected insect feces under inert gas at a low temperature of 400-700°C, a holding time of 0.5-4 hours, and a heating rate of 1-10°C / min; S3. Collect the product, pickle it, dry it, and then carbonize it at high temperature under inert gas to obtain a hard carbon material.

2. The method for preparing a biomass hard carbon negative electrode material for a sodium ion battery according to claim 1, characterized in that: In step S2, the pre-carbonization temperature is 600°C, the temperature is kept for 2 hours, and the heating rate is 5°C / min.

3. The method for preparing a biomass hard carbon negative electrode material for sodium ion batteries according to claim 1, characterized in that: The pickling in step S3 is performed using hydrochloric acid with a concentration of 0.5-5 mol / L and a pickling time of 0.5-12 h.

4. The method for preparing a biomass hard carbon negative electrode material for a sodium ion battery according to claim 1, characterized in that: The drying in step S3 is performed at 70°C.

5. The method for preparing a biomass hard carbon negative electrode material for sodium ion batteries according to claim 1, characterized in that: In step S3, the temperature of high-temperature carbonization is 900-1600° C., the holding time is 0.5-4 hours, and the heating rate is 1-10° C. / min.

6. The method for preparing a biomass hard carbon negative electrode material for sodium ion batteries according to claim 5, characterized in that: In step S3, the carbonization temperature is 1400° C., the temperature is kept at this temperature for 2 hours, and the heating rate is 5° C. / min.

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