CN-121990558-A - Lignin-based composite hard carbon material and preparation method and application thereof

CN121990558ACN 121990558 ACN121990558 ACN 121990558ACN-121990558-A

Abstract

The invention discloses a lignin-based composite hard carbon material, and a preparation method and application thereof, and belongs to the technical field of sodium ion batteries. The preparation method of the lignin-based composite hard carbon material comprises the following steps of dissolving lignin in a mixed solution of urea and alkali to prepare a lignin solution, adding a solution containing a positive charge reagent, reacting and concentrating to obtain a positive charge lignin solution, adding a nano cellulose dispersion liquid into the solution, performing hydrothermal treatment, filtering and drying the obtained reaction liquid to obtain a lignin-nano cellulose composite precursor, pre-oxidizing the composite precursor to obtain a high-crosslinking lignin-nano cellulose composite precursor, and carbonizing the high-crosslinking lignin-nano cellulose composite precursor to obtain the lignin-nano cellulose composite precursor. The lignin-based composite hard carbon material has multidimensional crosslinking characteristics, large interlayer spacing and abundant graphite-like microcrystals in structure, and has high reversible capacity and excellent multiplying power performance in the aspect of sodium ion battery energy storage.

Inventors

QIU XUEQING
XIAO TAO
Fu Fangbao
ZHANG WENLI
LIN XULIANG
QIN YANLIN
ZHU DONGYU
LIU QIYU
QIU WENLIAN

Assignees

广东工业大学

Dates

Publication Date: 20260508
Application Date: 20260306

Claims (10)

1. The preparation method of the lignin-based composite hard carbon material is characterized by comprising the following steps of: (1) Dissolving lignin in a mixed solution of urea and alkali to prepare a lignin solution with the concentration of 2-10 g/L, controlling the pH value of the solution to be 10-12, adding a solution containing a positive charge reagent with the concentration of 2-10 g/L, reacting for 2-6 hours at 80-100 ℃, and concentrating to obtain a positive charge lignin solution; (2) Adding the nano cellulose dispersion liquid into the positive charge lignin solution, performing hydrothermal treatment for 6-12 hours at 120-180 ℃, and filtering and drying the obtained reaction liquid to obtain a lignin-nano cellulose composite precursor; (3) Pre-oxidizing the lignin-nanocellulose composite precursor to obtain a high-crosslinking lignin-nanocellulose composite precursor; (4) Carbonizing the Gao Jiaolian lignin-nanocellulose composite precursor in inert gas to obtain the lignin-based composite hard carbon material.
2. The method for preparing the lignin-based composite hard carbon material according to claim 1, wherein the lignin is at least one of masson pine alkali lignin, reed alkali lignin, mao Zhujian lignin, wheat straw alkali lignin and corncob alkali lignin, the alkali is at least one of sodium hydroxide, potassium hydroxide, sodium carbonate and sodium bicarbonate, and the positive charge agent is at least one of cetyltrimethylammonium chloride, alkyl dimethylbenzyl ammonium chloride, didecyl dimethyl ammonium chloride and methyl tributyl ammonium chloride.
3. The preparation method of the lignin-based composite hard carbon material is characterized in that the mass ratio of lignin to urea to alkali to positive charge reagent to nanocellulose is 100:10-50:20-100:20-200.
4. The method for preparing the lignin-based composite hard carbon material according to claim 3, wherein the mass ratio of lignin to urea to alkali to positive charge reagent to nanocellulose is 100:10-30:20-60:30-80:50-120.
5. The method for preparing the lignin-based composite hard carbon material according to claim 1, wherein the concentration is heating concentration, the heating temperature is 80-100 ℃, and the concentration of the obtained positive charge lignin solution is 30-50 wt%.
6. The method for preparing the lignin-based composite hard carbon material according to claim 1, wherein the concentration of the nanocellulose dispersion liquid is 2-6wt%, and the nanocellulose is at least one of nanocellulose prepared by a mechanical method, carboxyl nanocellulose prepared by a Tempo oxidation method, carboxylated nanocellulose prepared by an etherification method and carboxyl nanocrystallines prepared by an acidolysis method, and the diameter is 10-30 nm, and the length is 1-20 mu m.
7. The method for preparing the lignin-based composite hard carbon material according to claim 1, wherein the hydrothermal treatment is performed in a blast oven by taking a hydrothermal kettle as a container, and the drying is vacuum drying, infrared drying or freeze drying.
8. The preparation method of the lignin-based composite hard carbon material according to claim 1, wherein the pre-oxidation is performed by a vulcanizing press, the pre-oxidation pressure is 0.1-1 Mpa, the pre-oxidation temperature is 150-250 ℃, the pre-oxidation time is 0.5-4 h, the carbonization temperature is 1000-1500 ℃, the carbonization time is 3-6 h, the heating rate is 2-5 ℃ per minute, and the inert gas is nitrogen or argon.
9. The lignin-based composite hard carbon material prepared by the preparation method of the lignin-based composite hard carbon material of any one of claims 1-8.
10. The use of the lignin-based composite hard carbon material of claim 9 in a negative electrode material of a sodium ion battery.

Description

Lignin-based composite hard carbon material and preparation method and application thereof Technical Field The invention belongs to the technical field of sodium ion batteries, and particularly relates to a lignin-based composite hard carbon material, and a preparation method and application thereof. Background In recent years, price fluctuations and limited reserves of lithium resources have put tremendous pressure on future applications of Lithium Ion Batteries (LIBs) in energy storage systems. Sodium Ion Batteries (SIBs) are considered to be an effective supplement to LIBs due to the abundant reserves of sodium resources, high safety and excellent high and low temperature performance. High performance anode materials are key to SIB development, and metal oxides, phosphides, organic materials, and hard carbon are the most widely studied SIB anode materials. The hard carbon has the advantages of wide precursor source, high reversible capacity, low sodium storage potential platform and the like, and is the anode material with the most commercialized prospect at present. The sodium storage mechanism of hard carbon is mainly adsorption-packing, where the main capacity derives from the plateau capacity created by the packing of sodium ions in the closed cells. Thus, increasing the closed cell volume of hard carbon is an effective method of increasing its reversible capacity. Although the conventional regulation and control method (increasing carbonization temperature, pore-forming by a template method and the like) can effectively improve the closed pore volume, the closed pore diameter is inevitably increased, the microcrystalline stacking degree is improved, the adsorption of sodium ions is weakened, and the multiplying power performance is reduced. Therefore, how to regulate and control the microstructure of the hard carbon, so that the hard carbon has both high sodium storage capacity and high rate performance, and becomes one of hot spots of hard carbon research. The lignocellulose raw materials such as cellulose, lignin and the like have wide sources and low cost, and are hard carbon precursors which are paid attention to nowadays. However, the hard carbon structure prepared by single lignin or cellulose has certain limitation, and is difficult to have high capacity and high multiplying power. Lignin has a cross-linked aromatic structure, forms highly disordered amorphous carbon after carbonization, and provides considerable reversible capacity through abundant micropores and defect sites, but pi-pi aggregation leads to compact lignin-based hard carbon structure, seriously hinders electron conduction and ion diffusion, and has poor multiplying power performance. In the prior art, polyaniline, polypyrrole and lignin are compounded and carbonized to prepare hard carbon with high capacity and high multiplying power, but the polyaniline and the polypyrrole have higher cost and are not beneficial to large-scale production. Cellulose can release free radicals in the pyrolysis process, promote the development of closed pores and carbon layers, provide a good transmission channel for sodium ions, and the obtained hard carbon shows excellent multiplying power characteristics. However, the high crystallinity of cellulose allows the formation of relatively ordered microcrystalline structures from hard carbon, limiting the formation of defect sites, resulting in lower plateau and overall capacities. The regulation and control of the lignocellulose composite structure are effective means for improving the sodium storage performance of the hard carbon, and through intermolecular interaction, the crosslinking and carbonization behaviors in the pyrolysis process are regulated and controlled, so that the overgrowth of hard carbon graphite microcrystals can be effectively inhibited, and the pore structure and defects are optimized. In the prior art, the regulation and control of the lignocellulose composite structure are two ways, namely pretreatment is carried out on lignocellulose raw materials, components are disassembled, and the content of the components is regulated and controlled. The willow branches are pretreated by hydrochloric acid water, hemicellulose and other impurities are effectively removed, but the hard carbon prepared by the method has low capacity and rate capability, lignin and hemicellulose are damaged, and the regulation and control are not easy. Or the bamboo powder is subjected to sulfuric acid water heat treatment, hemicellulose is effectively removed, and the obtained hard carbon has larger closed pore volume and smaller closed pore diameter, so that the electrochemical performance is improved. However, the hydrothermal pretreatment process takes a long time, lignin and cellulose are inevitably degraded in the hydrothermal process, the content is difficult to control, and the utilization rate of components is low. The second way of controlling the lignocellulosic composite structure is to recons