Preparation method for applying bamboo asphalt-based composite material to sodium ion battery

Abstract

The invention relates to the technical field of sodium ion battery manufacturing, in particular to a preparation method for applying a bamboo asphalt-based composite material to a sodium ion battery, which comprises the following steps: (1) dissolving citric acid in deionized water to prepare a citric acid solution; (2) uniformly mixing bamboo powder with asphalt; (3) pouring ethanol and a citric acid solution into the asphalt and bamboo powder mixture, and magnetically stirring; (4) drying the mixture, and performing primary carbonization; (5) further performing secondary carbonization on the sample; and finally collecting the sample. The influence of different carbonization temperatures and pre-oxidation steps on the hard carbon material is discussed, the asphalt and the biomass carbon material are mixed to prepare the hard carbon material, the cycling stability of the material is improved, meanwhile, the yield is increased, and the cost is reduced.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of sodium ion battery manufacturing, in particular to a preparation method of a bamboo pitch-based composite material applied to a sodium ion battery. BACKGROUND

[0002] Compared with lithium ion batteries, sodium ion batteries have strong competitiveness in terms of resource reserves, cost, safety and service life, and have good charge-discharge performance in high and low temperature environments. The working temperature range of lithium ion batteries is-20 DEG C to 60 DEG C, and the sodium ion battery can normally work at-40 DEG C to 70 DEG C, and the capacity retention rate is close to 90% at-20 DEG C, which can solve the problem of low efficiency of energy storage power stations in high-cold regions.

[0003] At present, biomass hard carbon is the best sodium ion battery negative electrode material, mainly taking straw, sawdust, coconut shell and other biomass as raw materials, and being prepared into hard carbon negative electrode material through crushing, screening, sintering and impurity removal processes. However, the yield of biomass hard carbon is low at present, and it is urgent to improve the yield and reduce the cost. SUMMARY

[0004] The purpose of the application is to provide a preparation method of a bamboo pitch-based composite material applied to a sodium ion battery, which takes bamboo as a biomass hard carbon raw material, uses pitch and biomass hard carbon to improve the yield of the material, adds citric acid to improve the crystallinity of bamboo fibers, and obtains a hard carbon negative electrode material after twice sintering, and discusses the influence of pre-oxidation on the material, the influence of carbonization temperature on the material and the influence of hydrochloric acid pickling on the material.

[0005] To achieve the above purpose, the application provides the following technical scheme: a preparation method of a bamboo pitch-based composite material applied to a sodium ion battery, comprising the following steps: 1) 1-10 g of citric acid is dissolved in 10-500 ml of deionized water to obtain a citric acid solution; 2) 1-10 g of bamboo powder and 1-20 g of pitch are mixed and ground to be uniform; 3) 10-100 ml of ethanol and the citric acid solution are poured into the bamboo powder and pitch mixture, and magnetic stirring is carried out for 1-30 h; 4) the mixed liquid is dried and carbonized once, the carbonization temperature is increased from room temperature to 100-1000 DEG C at a rate of 1-20 DEG C / min and kept for 1-10 h; 5) twice carbonization: from room temperature to 800 DEG C-1500 DEG C at a rate of 1-20 DEG C / min and kept for 1-10 h; 6) finally collect the sample.

[0006] Preferably, the pitch is coal tar pitch, petroleum pitch or sulfonated pitch.

[0007] Preferably, the primary carbonization step can be replaced by a pre-oxidation step.

[0008] Compared with the prior art, the present application has the following advantages: The method of the present application uses bamboo as a biomass raw material, and the pitch is compounded with the bamboo to improve the yield of the material, and the pitch is inexpensive, further reducing the cost. By adding citric acid to remove most of the cellulose and pectin and other amorphous region impurities of the bamboo raw material, the citric acid will undergo esterification with the plant fibers, so that the cellulose surface contains a large number of carboxyl functional groups, and the carboxyl groups on the surface of the cellulose will form hydrogen bonds with the carbonyl groups on the pitch, so that the cellulose and the pitch have good interfacial compatibility, and the crystallinity and thermal stability of the fibers are improved during the carbonization process. Therefore, adding citric acid during the preparation of the biomass and pitch composite material helps to improve the physical and chemical properties of the material, and also has the advantages of reducing the cost and improving the yield of the material. BRIEF DESCRIPTION OF DRAWINGS

[0009] Fig. 1 SEM image of the ZHN material of the present application; Fig. 2 Cycle diagram of the ZHN of the present application at a current density of 0.1C. DETAILED DESCRIPTION

[0010] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0011] Please refer to Figs. 1-2 A preparation method of a bamboo pitch-based composite material applied to a sodium ion battery, comprising the following steps: 1) Dissolve 1-10 g of citric acid in 10-500 ml of deionized water to obtain a citric acid solution; 2) Mix and grind 1-10 g of bamboo powder and 1-20 g of pitch until uniform; 3) Pour 10-100 ml of ethanol and the citric acid solution into the bamboo pitch mixture and magnetically stir for 1-30 h; 4) Dry the mixed liquid and then carbonize, the carbonization temperature is increased from room temperature to 100-1000℃ at a rate of 1-20℃ / min and maintained for 1-10 h; 5) Secondary carbonization: from room temperature 1-10 h to 800-1500 °C and keep 1-10 h, the heating rate is 1-20 °C / min; 6) Final collection of sample.

[0012] The pitch is coal tar pitch, petroleum pitch or sulfonated pitch.

[0013] The primary carbonization step can be replaced by a pre-oxidation step.

[0014] Example 1 A preparation method of a bamboo pitch-based composite material applied to a sodium ion battery, the specific steps are as follows: 1) Take 2 g of citric acid and dissolve it in 30 ml of deionized water to obtain a citric acid solution; 2) Take 2 g of bamboo powder and 2 g of pitch and mix and grind them uniformly; 3) Pour 30 ml of ethanol and the citric acid solution into the bamboo powder and pitch mixture and magnetically stir for 18 h; 4) Dry the mixed liquid and then perform primary carbonization, the carbonization temperature is increased from room temperature to 600 °C and kept for 2 h, the heating rate is 5 °C / min; 5) Secondary carbonization: from room temperature 260 min to 1300 °C and keep 2 h, the heating rate is 5 °C / min; 6) Final collection of sample.

[0015] Example 2 A preparation method of a bamboo pitch-based composite material applied to a sodium ion battery, the specific steps are as follows: 1) Take 2 g of citric acid and dissolve it in 30 ml of deionized water to obtain a citric acid solution; 2) Take 2 g of bamboo powder and 2 g of pitch and mix and grind them uniformly; 3) Pour 30 ml of ethanol and the citric acid solution into the bamboo powder and pitch mixture and magnetically stir for 18 h; 4) Dry the mixed liquid and then perform primary carbonization, the carbonization temperature is increased from room temperature to 800 °C and kept for 2 h, the heating rate is 5 °C / min; 5) Secondary carbonization: from room temperature 220 min to 1100 °C and keep 2 h, the heating rate is 5 °C / min; 6) Final collection of sample.

[0016] Example 3 A preparation method of a bamboo pitch-based composite material applied to a sodium ion battery, the specific steps are as follows: 1) Take 2 g of bamboo powder and 2 g of pitch and mix them by ball milling until uniform; 2) Pre-oxidation: from room temperature to 300°C for 90 min and keep 2 h, the heating rate is 3°C / min; 3) Carbonization: from room temperature to 1300°C for 260 min and keep 2 h, the heating rate is 5°C / min; 4) Collect the sample finally.

[0017] Example 4 A preparation method of a bamboo pitch-based composite material applied to a sodium ion battery, the specific steps are as follows: 1) Take 2 g of bamboo powder and 2 g of pitch and mix them uniformly by ball milling; 2) First carbonization: from room temperature to 600°C for 2 h and keep 2 h, the heating rate is 5°C / min; 3) Second carbonization: from room temperature to 1300°C for 260 min and keep 2 h, the heating rate is 5°C / min; 4) Collect the sample finally.

[0018] Example 5 A preparation method of a bamboo pitch-based composite material applied to a sodium ion battery, the specific steps are as follows: 1) Take 2 g of citric acid, 2 g of bamboo powder and 1 g of pitch and mix them uniformly by grinding; 2) First carbonization: from room temperature to 800°C for 160 min and keep 2 h, the heating rate is 5°C / min; 3) Second carbonization: from room temperature to 1100°C for 220 min and keep 2 h, the heating rate is 5°C / min; 4) Collect the sample finally.

[0019] Although the embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a bamboo-based asphalt composite material for use in sodium-ion batteries, characterized in that: Includes the following steps: 1) Dissolve 1–10 g of citric acid in 10–500 ml of deionized water to obtain a citric acid solution; 2) Take 1-10 g of bamboo powder and 1-20 g of asphalt, mix and grind until uniform; 3) Pour 10-100 ml of ethanol and citric acid solution into the bamboo powder and asphalt mixture and stir magnetically for 1-30 h; 4) After drying the mixed liquid, carbonize it once. The carbonization temperature is increased from room temperature for 1-10 h to 100-1000℃ and maintained for 1-10 h. The heating rate is 1-20℃ / min. 5) Secondary carbonization: Increase the temperature from room temperature to 800℃ to 1500℃ in 1 to 10 hours and maintain it for 1 to 10 hours, with a heating rate of 1 to 20℃ / min; 6) Finally, collect the samples.

2. The method for preparing a bamboo asphalt-based composite material for sodium-ion batteries according to claim 1, characterized in that: The asphalt is coal tar pitch, petroleum pitch, or sulfonated pitch.

3. The method for preparing a bamboo asphalt-based composite material for sodium-ion batteries according to claim 1, characterized in that: The aforementioned carbonization step can be replaced by a pre-oxidation step.

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