CN-117585665-B - Hard carbon negative electrode material of sodium ion battery and preparation method thereof

CN117585665BCN 117585665 BCN117585665 BCN 117585665BCN-117585665-B

Abstract

The invention discloses a hard carbon negative electrode material of a sodium ion battery and a preparation method thereof, and relates to the technical field of sodium ion batteries. The hard carbon negative electrode material of the sodium ion battery is prepared by pretreating lignocellulose-containing raw materials in a eutectic solvent, then treating the lignocellulose-containing raw materials in Lewis acid and carbonizing the lignocellulose-containing raw materials, wherein the lignocellulose-containing raw materials are subjected to crushing treatment before pretreatment, the particle size of the crushed lignocellulose-containing raw materials is 100-200 meshes, and the Lewis acid contains transition metal elements. According to the invention, after the lignocellulose-containing raw material, the eutectic solvent and the Lewis acid are pretreated, the microstructure of the lignocellulose-containing bio-based carbon material can be regulated and controlled, stable and reversible intercalation and deintercalation of sodium ions in the carbon structure are realized, and the lignocellulose-containing raw material is applied to a battery and has excellent cycle stability and rate capability.

Inventors

YANG WANG
YANG WU
TANG HANLIANG
LI GUIQIN
CHEN ZHISHAN
WU YANRU

Assignees

清远高新华园科技协同创新研究院有限公司

Dates

Publication Date: 20260505
Application Date: 20231124

Claims (5)

1. The hard carbon negative electrode material of the sodium ion battery is characterized in that the hard carbon negative electrode material of the sodium ion battery is formed by pretreating lignocellulose-containing raw materials in a eutectic solvent, then treating in Lewis acid and carbonizing; before pretreatment, crushing the lignocellulose-containing raw material, wherein the particle size of the crushed lignocellulose-containing raw material is 100-200 meshes; The Lewis acid contains transition metal elements; the eutectic solvent is mixed by imidazolium salt and urea and ethylene glycol according to a molar ratio of 1:5:5; the Lewis acid is at least one of ferric chloride, cobalt chloride, nickel chloride, copper chloride, manganese chloride, aluminum chloride and zinc chloride.
2. The hard carbon negative electrode material of sodium ion battery according to claim 1, wherein the lewis acid is a mixture of nickel chloride and copper chloride, and the mass ratio of nickel chloride to copper chloride is (0.2-5): 1.
3. The hard carbon negative electrode material of a sodium ion battery according to claim 1, wherein the lignocellulose-containing material is at least one of wood, bamboo, corncob, straw, and artificial board.
4. A method for preparing a hard carbon negative electrode material of a sodium ion battery according to any one of claims 1 to 3, comprising the steps of: (1) Adding a lignocellulose-containing raw material into a eutectic solvent, pretreating for 2-8 hours at 80-100 ℃, and drying to obtain precursor particles, wherein the mass ratio of the lignocellulose-containing raw material to the eutectic solvent is (1-3) 20; (2) Adding precursor particles into a Lewis acid solution and pre-treating the precursor particles for 8-12 hours at 70-100 ℃ to obtain a cellulose/lignin composite precursor, wherein the mass ratio of the precursor particles to the Lewis acid is 1 (1-4); (3) And (3) carbonizing the cellulose/lignin composite precursor at a high temperature in an inert atmosphere to obtain the hard carbon anode material of the sodium ion battery.
5. The method for preparing a hard carbon negative electrode material of a sodium ion battery according to claim 4, wherein the carbonization temperature in the step (3) is 800-1200 ℃, the carbonization time is 1-3h, and the heating rate is 3-5 ℃ per minute.

Description

Hard carbon negative electrode material of sodium ion battery and preparation method thereof Technical Field The invention relates to the technical field of sodium ion batteries, in particular to a hard carbon negative electrode material of a sodium ion battery and a preparation method thereof. Background In recent years, carbon emissions from fossil energy consumption have led to an increasing prominence of environmental problems, and the development of new renewable resources has become a consensus in today's society. The lignocellulose biomass has the advantages of rich resources, reproducibility, environmental friendliness and the like, so that the development of biomass-based functional materials by using lignocellulose raw materials has important significance for realizing sustainable development of society and economy, and also meets the important requirement of the current conversion of social energy consumption structures to low carbonization and clean. The carbon material has many excellent physical and chemical properties, such as high chemical stability, adjustable surface chemical property, good conductivity, low density, large specific surface area and the like, so the carbon material has good application prospect in the fields of catalysis, energy storage, conversion, adsorption and the like. However, most synthetic routes to carbon materials generally rely on non-renewable fossil fuels, so lignocellulosic biomass as a sustainable carbon source can alleviate the current society's tremendous pressure on energy and environment. As with lithium ion batteries, sodium ion batteries are mainly composed of a positive electrode, a negative electrode, a current collector, an electrolyte, a separator and a battery case. The carbon-based negative electrode material of the lithium ion battery mainly comprises graphite, the radius of lithium ions is smaller, the lithium ions can be effectively intercalated and deintercalated between graphite layers, but the radius of sodium ions is larger, and the graphite material can not effectively store the sodium ions. Lignocellulosic biomass-based hard carbon materials have received great attention as negative electrode materials for sodium ion batteries. Changing carbonization process parameters (carbonization temperature, temperature change rate, carbonization mode, etc.) is considered to be a very effective idea for regulating and controlling hard carbon microstructure. However, an increase in carbonization temperature means an increase in energy consumption, and the high-temperature graphitized carbon layer structure is more similar to graphite, and the smaller layer spacing is disadvantageous for intercalation of ions with larger radius such as Na +, thereby affecting the subsequent ion storage capacity. Disclosure of Invention The invention aims to overcome the defects of the prior art and provides a hard carbon negative electrode material of a sodium ion battery and a preparation method thereof. After the lignocellulose-containing raw material, the eutectic solvent and the Lewis acid are pretreated, the controllable construction of the microstructure such as an ordered carbon layer structure, a carbon layer spacing, a pore structure and the like of the lignocellulose-containing bio-based carbon material can be realized, the stable and reversible intercalation and deintercalation of sodium ions in the carbon structure can be realized, and the lignocellulose-containing bio-based carbon material has excellent cycle stability and rate capability when applied to a battery. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: In a first aspect, the invention provides a hard carbon negative electrode material of a sodium ion battery, which is formed by pretreating a lignocellulose-containing raw material in a eutectic solvent, then treating in Lewis acid and carbonizing; before pretreatment, crushing the lignocellulose-containing raw material, wherein the particle size of the crushed lignocellulose-containing raw material is 100-200 meshes; The Lewis acid contains transition metal elements. The method comprises the following steps of pretreating lignocellulose-containing raw materials with a eutectic solvent, wherein the eutectic solvent has good dissolution effect on lignin, hemicellulose and lignin in the raw materials can be effectively dissolved out, then adding Lewis acid for treatment, and obtaining a cellulose/lignin composite structure chelated with transition metal ions due to interaction between transition metal cation hydrate in the Lewis acid and oxygen atoms at C5 and C6 positions of cellulose, so that the transition metal plays a role in catalyzing graphitization in the carbonization process in the subsequent carbonization process, the graphitization degree and conductivity of a carbon material are improved, the cellulose/lignin composite structure is carbonized to obtain a micro carbon structure favorable