CN115249799A

CN115249799A - Rosin-based nitrogen-doped coated hard carbon negative electrode material of sodium ion battery and preparation method of rosin-based nitrogen-doped coated hard carbon negative electrode material

Info

Publication number: CN115249799A
Application number: CN202210815699.1A
Authority: CN
Inventors: 黄祥岚; 谌芳园; 葛传长
Original assignee: Guangdong Kaijin New Energy Technology Co Ltd
Current assignee: Guangdong Kaijin New Energy Technology Co Ltd
Priority date: 2022-07-12
Filing date: 2022-07-12
Publication date: 2022-10-28

Abstract

The invention discloses a rosin-based nitrogen-doped coated hard carbon negative electrode material of a sodium ion battery and a preparation method thereof, wherein the preparation method comprises the following steps: carrying out heat treatment on the hard carbon precursor material, and crushing by using a jet mill to obtain hard carbon powder; uniformly mixing a nitrogen source, rosin and deionized water, carrying out heat treatment, cooling, and then crushing and sieving by using a sand mill to obtain rosin-based nitrogen-doped powder; uniformly mixing hard carbon powder and rosin-based nitrogen-doped powder, adding sodium carboxymethylcellulose, and uniformly stirring to obtain a mixture; and carbonizing the mixture, cooling, transferring into an acid solution, washing, drying, grinding and sieving to obtain the cathode material. The rosin-based nitrogen-doped coated hard carbon negative electrode materialThe average volume particle diameter Dv50 of the material is 4.3-6.1 μm, and the specific surface area is 4.8-11.7 m ² The first reversible capacity of 0.1C is more than or equal to 320.9mAh/g and can reach 460.4Ah/g to the maximum, and the first charging and discharging coulombic efficiency of 0.1C is more than or equal to 81.9 percent and can reach 90.3 to the maximum.

Description

Rosin-based nitrogen-doped coated hard carbon negative electrode material of sodium ion battery and preparation method of rosin-based nitrogen-doped coated hard carbon negative electrode material

Technical Field

The invention relates to the field of sodium ion battery materials, in particular to a rosin-based nitrogen-doped coated hard carbon negative electrode material of a sodium ion battery and a preparation method thereof.

Background

With the rapid development of large-scale smart power grids and the popularization and application of electric vehicles, lithium resources cannot meet the huge requirements of lithium ion batteries, and it is necessary to develop an energy storage technology capable of replacing the lithium ion batteries. By 2022, in the element content data in the crustal, centuries encyclopedic showed that sodium is the fourth metal element in the abundance rows of the crustal, about 2.7451%, is widely distributed and easily obtained, has an annual output of 200000 tons, belongs to the same group of elements with lithium (about 0.0019% of lithium and 39000 tons of annual output), and is a feasible battery raw material for replacing lithium.

At present, the cathode material of the commonly used sodium ion battery includes carbon material, metal oxygen/sulfide or alloy material. Since the hard carbon material has a stable structure, a long cycle life, a high lithium intercalation potential, and high safety, and has a microcrystalline structure that facilitates the entry and exit of sodium ions, it is effective for the increase of the output power of the battery. However, the hard carbon material is not widely used and is difficult to develop, wherein the important reason is that the energy density is low, the capacity of the prepared hard carbon material is mostly between 250mAh/g and 300mAh/g, the first efficiency is generally between 75% and 80%, a balanced state cannot be achieved between the cost and the performance, and the mass production of the hard carbon material is greatly limited.

Disclosure of Invention

The invention provides a rosin-based nitrogen-doped coated hard carbon negative electrode material of a sodium ion battery and a preparation method thereof in order to overcome the defects, and solves the problems of low energy density and poor first charge-discharge coulombic efficiency performance of the hard carbon negative electrode material of the sodium ion battery.

In order to achieve the above purpose, the invention is realized by the following technical scheme:

a sodium ion battery rosin-based nitrogen-doped coated hard carbon negative electrode material and a preparation method thereof comprise the following steps:

(1) Carrying out heat treatment on the hard carbon precursor material in an inert atmosphere, cooling, and then carrying out jet milling and crushing to obtain hard carbon powder;

(2) Uniformly mixing a nitrogen source, rosin and deionized water, then carrying out heat treatment, cooling, and then carrying out sand mill crushing and screening to obtain rosin-based nitrogen-doped powder;

(3) Uniformly mixing hard carbon powder and rosin-based nitrogen-doped powder, adding sodium carboxymethylcellulose, and uniformly stirring to obtain a mixture; and carbonizing the mixture under an inert atmosphere, cooling, transferring the mixture into an acid solution, stirring, washing, filtering to be neutral, drying, grinding and screening to obtain the rosin-based nitrogen-doped coated hard carbon negative electrode material of the sodium ion battery.

Preferably, the hard carbon material in step (1) is one or more of cellulose, hemicellulose and lignin.

Preferably, the hard carbon material in the step (1) is cellulose, hemicellulose and lignin, and the mass ratio of the cellulose to the total mass of the hemicellulose and the lignin is 0.1 to 0.9.

Preferably, the heat treatment in the step (1) is carried out at the heating temperature of 200-700 ℃ and the heat preservation time of 2-6 h; the average volume particle diameter Dv50 of the hard carbon powder is controlled to be 4-10 mu m, and the specific surface area is 5.4-18.4 m ² /g。

Preferably, the heat treatment in the step (2) is drying at 200 ℃ for 12h under a nitrogen atmosphere; the mass ratio of the nitrogen source to the rosin is 0.1-0.9; the average volume particle diameter Dv50 of the rosin-based nitrogen-doped powder is controlled to be 4-10 mu m.

Preferably, the rosin in step (2) is gum rosin, wood rosin or tall oil rosin; the nitrogen source is one or more of urea, melamine, biuret and aniline.

Preferably, the mass ratio of the hard carbon powder to the rosin-based nitrogen-doped powder in the step (3) is 0.1 to 0.9, and the mass ratio of the added mass of the sodium carboxymethyl cellulose to the total mass ratio of the hard carbon powder to the rosin-based nitrogen-doped powder is 0.11 to 0.43.

Preferably, the carbonization mixture in the step (3) is subjected to heat preservation for 2 to 6 hours at the temperature of 900 to 1500 ℃; the acid solution is acetic acid solution, hydrochloric acid solution, sulfuric acid solution or nitric acid solution.

Preferably, the inert atmosphere is nitrogen gas or argon gas, and the gas flow rate is 1-5L/min.

The invention also provides a rosin-based nitrogen-doped coated hard carbon negative electrode material of the sodium ion battery, which is prepared by the preparation method of the rosin-based nitrogen-doped coated hard carbon negative electrode material of the sodium ion battery, wherein the average volume particle diameter Dv50 of the rosin-based nitrogen-doped coated hard carbon negative electrode material is 4.3-6.1 mu m, and the specific surface area is 4.8-11.7 m ² The first reversible capacity of 0.1C is more than or equal to 320.9mAh/g, and the first charging and discharging coulombic efficiency of 0.1C is more than or equal to 81.9%.

Compared with the prior art, the invention has the beneficial effects that: the invention takes a hard carbon material as a main body, adopts specially selected nitrogen source mixed rosin as a coating body, and the coated hard carbon material has chemical stability, high mechanical strength and larger specific surface area; the coating layer can provide a large number of electroactive sites, form a short ion channel, generate high conductivity and remarkably improve electrochemical performance, and the average volume particle size Dv50 of the material is 4.3-6.1 mu m, and the specific surface area is 4.8-11.7 m ² The first reversible capacity of 0.1C is more than or equal to 320.9mAh/g and can reach 460.4Ah/g to the maximum, and the first charging and discharging coulombic efficiency of 0.1C is more than or equal to 81.9 percent and can reach 90.3 percent to the maximum; the rosin-based nitrogen-doped coated hard carbon material can effectively inhibit the aggregation of nano particles, thereby inhibiting the reduction of the specific surface area, increasing the attachment sites of sodium ions and further improving the capacity of hard carbon.

Drawings

FIG. 1 is a graph showing the first charge and discharge curves of the hard carbon negative electrode material prepared in example 1;

FIG. 2 is a graph showing the first charge and discharge curves of the hard carbon negative electrode material prepared in example 2;

FIG. 3 is a first charge-discharge curve diagram of the hard carbon negative electrode material prepared in example 3;

FIG. 4 is a first charge-discharge curve diagram of the hard carbon negative electrode material prepared in example 4;

FIG. 5 is a graph showing the first charge and discharge curves of the hard carbon negative electrode material prepared in example 5;

FIG. 6 is a graph showing the first charge and discharge curves of the hard carbon negative electrode material prepared in example 6;

FIG. 7 is a graph showing the first charge and discharge curves of the hard carbon negative electrode material prepared in example 7;

FIG. 8 is a graph showing the first charge and discharge curves of the hard carbon negative electrode material prepared in example 8;

FIG. 9 is a graph showing the first charge and discharge curves of the hard carbon negative electrode material prepared in example 9;

fig. 10 is a first charge-discharge curve diagram of the hard carbon negative electrode material prepared in example 10.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.

Example 1

(1) Firstly weighing 1kg of cellulose, placing the cellulose in a corundum crucible, placing the corundum crucible in a heating furnace, preserving heat for 4 hours under the conditions that the nitrogen flow is 1L/min and the heating temperature is 350 ℃, taking out the crucible after the temperature in the heating furnace is reduced to room temperature, taking out materials in the crucible, then grinding by a jet mill, sieving, and controlling the average volume particle size Dv50 of discharged materials to be 4 mu m to obtain hard carbon powder;

(2) Putting 9.5g and 90.5g of urea and gum rosin in a 1000ml beaker, adding 500ml of deionized water, stirring uniformly, drying at 200 ℃ for 12h in a nitrogen oven, cooling, crushing by using a sand mill, sieving to control the average volume particle size Dv50 of the discharged material to be 10 mu m, and sieving by using a 500-mesh sieve to obtain rosin-based nitrogen-doped powder;

(3) Uniformly mixing 9.5g of hard carbon crushed material and 90.5g of rosin-based nitrogen-doped powder, adding 11g of sodium carboxymethylcellulose, uniformly stirring the mixture, then loading the mixture into a corundum crucible, placing the corundum crucible into a tubular furnace, carbonizing the mixture under the environment of nitrogen flow of 3L/min, wherein the carbonization temperature is 900 ℃, the carbonization heat preservation time is 6 hours, taking out the mixture after the internal temperature of the tubular furnace is reduced to room temperature, soaking the mixture into an acetic acid solution, fully stirring the mixture, then washing the mixture with deionized water to be neutral, drying and grinding the mixture, and then screening the mixture with a 500-mesh screen to obtain the rosin-based nitrogen-doped coated hard carbon cathode material of the sodium ion battery.

Example 2

(1) Firstly weighing 1kg of hemicellulose, placing the hemicellulose into a corundum crucible, placing the corundum crucible into a heating furnace, preserving heat for 6 hours under the conditions that the nitrogen flow is 1.5L/min and the heating temperature is 350 ℃, taking out the crucible after the temperature in the heating furnace is reduced to room temperature, taking out materials in the crucible, then crushing the materials by a jet mill, and sieving the materials to control the average volume particle size Dv50 of the discharged materials to be 10 mu m to obtain hard carbon powder;

(2) Putting urea and wood rosin into a 1000ml beaker according to the mass of 20g and 80g, adding 500ml deionized water, uniformly stirring, transferring into a nitrogen oven for drying at 200 ℃ for 12h, cooling, then crushing by using a sand mill, sieving to control the average volume particle size Dv50 of the discharged material to be 6 mu m, and sieving by using a 500-mesh sieve to obtain rosin-based nitrogen-doped powder;

(3) Taking 20g of hard carbon crushed aggregates and 80g of rosin-based nitrogen-doped powder, uniformly mixing, adding 27.5g of sodium carboxymethylcellulose, uniformly stirring the mixture, then placing the mixture into a corundum crucible, placing the corundum crucible into a tubular furnace, carbonizing the mixture in an environment with the nitrogen flow of 5L/min, wherein the carbonization temperature is 900 ℃, the carbonization heat preservation time is 6 hours, taking out the mixture when the internal temperature of the tubular furnace is reduced to room temperature, soaking the mixture into an acetic acid solution, fully stirring, washing the mixture with deionized water to be neutral, drying and grinding the mixture, and then screening the mixture through a 500-mesh screen to obtain the rosin-based nitrogen-doped coated hard carbon cathode material of the sodium ion battery.

Example 3

(1) Firstly weighing 1kg of lignin, placing the lignin in a corundum crucible, placing the corundum crucible in a heating furnace, preserving heat for 2 hours under the conditions that the nitrogen flow is 1.5L/min and the heating temperature is 700 ℃, taking out the crucible after the internal temperature of the heating furnace is reduced to room temperature, taking out materials in the crucible, then crushing by a jet mill, and sieving to control the average volume particle size Dv50 of discharged materials to be 6 mu m to obtain hard carbon powder;

(2) Putting melamine and gum rosin into a 1000ml beaker according to the mass ratio of 30g to 70g, adding 500ml deionized water, uniformly stirring, drying at 200 ℃ for 12h in a nitrogen oven, cooling, crushing by using a sand mill, sieving to control the average volume particle size Dv50 of the discharged material to be 10 mu m, and sieving the powder by using a 500-mesh sieve to obtain rosin-based nitrogen-doped powder;

(3) Taking 30g of hard carbon crushed material and 70g of rosin-based nitrogen-doped powder, uniformly mixing, adding 43g of sodium carboxymethylcellulose, uniformly stirring the mixture, then putting the mixture into a corundum crucible, putting the corundum crucible into a tubular furnace, carbonizing the mixture under the environment of 5L/min of nitrogen flow, wherein the carbonization temperature is 900 ℃, the carbonization heat preservation time is 5 hours, taking out the mixture when the internal temperature of the tubular furnace is reduced to room temperature, soaking the mixture into hydrochloric acid solution, fully stirring, washing the mixture with deionized water, filtering the mixture to be neutral, drying and grinding the mixture, and then screening the mixture through a 500-mesh screen to obtain the rosin-based nitrogen-doped coated hard carbon cathode material of the sodium ion battery.

Example 4

(1) Firstly weighing 0.1kg of cellulose, 0.4kg of hemicellulose and 0.5kg of lignin, placing the weighed corundum crucible in a corundum crucible, placing the corundum crucible in a heating furnace, keeping the temperature for 6 hours under the conditions that the nitrogen flow is 1L/min and the heating temperature is 200 ℃, taking out the crucible after the internal temperature of the heating furnace is reduced to room temperature, taking out materials in the crucible, then carrying out jet milling and crushing, and sieving to control the average volume particle size Dv50 of discharged materials to be 4 mu m so as to obtain hard carbon powder;

(2) Putting urea and tall oil rosin into a 1000ml beaker according to the mass ratio of 40g to 60g, adding 500ml deionized water, uniformly stirring, drying at 200 ℃ for 12h in a nitrogen oven, cooling, crushing by using a sand mill, sieving to control the average volume particle size Dv50 of the discharged material to be 4 mu m, and sieving the powder by using a 500-mesh sieve to obtain rosin-based nitrogen-doped powder;

(3) Taking 40g of hard carbon crushed material and 60g of rosin-based nitrogen-doped powder, uniformly mixing, adding 30g of sodium carboxymethylcellulose, uniformly stirring the mixture, then putting the mixture into a corundum crucible, putting the corundum crucible into a tubular furnace, carbonizing the mixture under the environment of 5L/min of nitrogen flow, wherein the carbonization temperature is 900 ℃, the carbonization heat preservation time is 6 hours, taking out the mixture when the internal temperature of the tubular furnace is reduced to room temperature, soaking the mixture into sulfuric acid solution, fully stirring, washing the mixture with deionized water, filtering the mixture to be neutral, drying and grinding the mixture, and then screening the mixture through a 500-mesh screen to obtain the rosin-based nitrogen-doped coated hard carbon cathode material of the sodium ion battery.

Example 5

(1) Firstly weighing 0.47kg of cellulose, 0.3kg of hemicellulose and 0.23kg of lignin, placing the weighed corundum crucible in a corundum crucible, placing the corundum crucible in a heating furnace, keeping the temperature for 6 hours under the conditions that the nitrogen flow is 1L/min and the heating temperature is 450 ℃, taking out the crucible after the internal temperature of the heating furnace is reduced to room temperature, taking out materials in the crucible, then carrying out jet milling and crushing, and sieving to control the average volume particle size Dv50 of discharged materials to be 4 mu m so as to obtain hard carbon powder;

(2) Putting aniline and wood rosin into a 1000ml beaker according to the mass ratio of 45g to 55g, adding 500ml deionized water, uniformly stirring, drying at 200 ℃ for 12h in a nitrogen oven, cooling, crushing by using a sand mill, sieving to control the average volume particle size Dv50 of the discharged material to be 8 mu m, and sieving the powder by using a 500-mesh sieve to obtain rosin-based nitrogen-doped powder;

(3) Taking 45g of hard carbon crushed materials and 55g of rosin-based nitrogen-doped powder, uniformly mixing, adding 11g of sodium carboxymethylcellulose, uniformly stirring the mixture, then putting the mixture into a corundum crucible, putting the corundum crucible into a tubular furnace, carbonizing the mixture under the environment of 5L/min of nitrogen flow, wherein the carbonization temperature is 1300 ℃, the carbonization heat preservation time is 2 hours, taking out the mixture when the internal temperature of the tubular furnace is reduced to room temperature, soaking the mixture into a nitric acid solution, fully stirring, washing the mixture with deionized water, filtering the mixture to be neutral, drying and grinding the mixture, and then screening the mixture through a 500-mesh screen to obtain the rosin-based nitrogen-doped coated hard carbon cathode material of the sodium ion battery.

Example 6

(1) Firstly weighing 0.2kg of cellulose, 0.5kg of hemicellulose and 0.3kg of lignin, placing the corundum crucible in a corundum crucible, placing the corundum crucible in a heating furnace, keeping the temperature for 6 hours under the conditions that the nitrogen flow is 1L/min and the heating temperature is 450 ℃, taking out the crucible after the internal temperature of the heating furnace is reduced to room temperature, taking out materials in the crucible, then carrying out jet milling and crushing, and sieving to control the average volume particle size Dv50 of discharged materials to be 4 mu m so as to obtain hard carbon powder;

(2) Putting aniline and tall oil rosin into a 1000ml beaker according to the mass ratio of 47g to 53g, adding 500ml deionized water, uniformly stirring, drying at 200 ℃ for 12h in a nitrogen oven, cooling, crushing by using a sand mill, sieving to control the average volume particle size Dv50 of the discharged material to be 4 mu m, and sieving by using a 500-mesh sieve to obtain rosin-based nitrogen-doped powder;

(3) And (2) uniformly mixing 47g of hard carbon crushed materials with 53g of rosin-based nitrogen-doped powder, adding 16.5g of sodium carboxymethylcellulose, uniformly stirring the mixture, then loading the mixture into a corundum crucible, placing the corundum crucible into a tubular furnace, carbonizing the mixture in an environment with the nitrogen flow of 5L/min, wherein the carbonization temperature is 1300 ℃, the carbonization heat preservation time is 5 hours, taking out the mixture when the internal temperature of the tubular furnace is reduced to room temperature, soaking the mixture into an acetic acid solution, fully stirring the mixture, washing the mixture with deionized water, filtering the mixture to be neutral, drying the mixture, grinding the mixture, and then screening the mixture through a 500-mesh screen to obtain the rosin-based nitrogen-doped coated hard carbon cathode material of the sodium ion battery.

Example 7

(1) Weighing 0.3kg of cellulose, 0.4kg of hemicellulose and 0.3kg of lignin, placing the weighed corundum crucible in a corundum crucible, placing the corundum crucible in a heating furnace, keeping the temperature for 6 hours under the conditions that the nitrogen flow is 1L/min and the heating temperature is 450 ℃, taking out the crucible after the internal temperature of the heating furnace is reduced to room temperature, taking out materials in the crucible, then carrying out jet milling and crushing, and sieving to control the average volume particle size Dv50 of discharged materials to be 4 mu m so as to obtain hard carbon powder;

(2) Putting biuret and gum rosin into a 1000ml beaker according to the mass ratio of 20g to 80g, adding 500ml deionized water, uniformly stirring, drying at 200 ℃ for 12h in a nitrogen oven, cooling, crushing by using a sand mill, sieving to control the average volume particle size Dv50 of the discharged material to be 4 mu m, and sieving by using a 500-mesh sieve to obtain rosin-based nitrogen-doped powder;

(3) And (2) uniformly mixing 47g of hard carbon crushed materials with 53g of rosin-based nitrogen-doped powder, adding 39g of sodium carboxymethylcellulose, uniformly stirring the mixture, then putting the mixture into a corundum crucible, putting the corundum crucible into a tubular furnace, carbonizing the mixture under the environment of 5L/min of nitrogen flow, wherein the carbonization temperature is 1300 ℃, the carbonization heat preservation time is 3 hours, taking out the mixture when the internal temperature of the tubular furnace is reduced to room temperature, soaking the mixture into an acetic acid solution, fully stirring the mixture, washing the mixture with deionized water to be neutral, drying and grinding the mixture, and then screening the mixture with a 500-mesh screen to obtain the rosin-based nitrogen-doped coated hard carbon cathode material of the sodium ion battery.

Example 8

(1) Weighing 0.4kg of cellulose, 0.3kg of hemicellulose and 0.3kg of lignin, placing the weighed corundum crucible in a corundum crucible, placing the corundum crucible in a heating furnace, keeping the temperature for 6 hours under the conditions that the nitrogen flow is 1L/min and the heating temperature is 450 ℃, taking out the crucible after the internal temperature of the heating furnace is reduced to room temperature, taking out materials in the crucible, then carrying out jet milling and crushing, and sieving to control the average volume particle size Dv50 of discharged materials to be 4 mu m so as to obtain hard carbon powder;

(2) Putting biuret and wood rosin into a 1000ml beaker according to the mass ratio of 47g to 53g, adding 500ml deionized water, uniformly stirring, drying at 200 ℃ for 12h in a nitrogen oven, cooling, crushing by using a sand mill, sieving to control the average volume particle size Dv50 of the discharged material to be 4 mu m, and sieving by using a 500-mesh sieve to obtain rosin-based nitrogen-doped powder;

(3) Taking 20g of hard carbon crushed aggregates and 80g of rosin-based nitrogen-doped powder, uniformly mixing, then adding 25.6g of sodium carboxymethylcellulose, uniformly stirring the mixture, then placing the mixture into a corundum crucible, placing the corundum crucible into a tubular furnace, carbonizing the mixture in an environment with argon flow of 5L/min, wherein the carbonization temperature is 1500 ℃, the carbonization heat preservation time is 2 hours, taking out the mixture after the internal temperature of the tubular furnace is reduced to room temperature, soaking the mixture into an acetic acid solution, fully stirring, then washing the mixture with deionized water to be neutral, drying and grinding the mixture, and then screening the mixture through a 500-mesh screen to obtain the rosin-based nitrogen-doped coated hard carbon cathode material of the sodium ion battery.

Example 9

(1) Weighing 0.3kg of cellulose, 0.3kg of hemicellulose and 0.4kg of lignin, placing the weighed corundum crucible in a corundum crucible, placing the corundum crucible in a heating furnace, keeping the temperature for 6 hours under the conditions that the nitrogen flow is 1L/min and the heating temperature is 450 ℃, taking out the crucible after the internal temperature of the heating furnace is reduced to room temperature, taking out materials in the crucible, then carrying out jet milling and crushing, and sieving to control the average volume particle size Dv50 of discharged materials to be 4 mu m so as to obtain hard carbon powder;

(2) Putting melamine and gum rosin into a 1000ml beaker according to the mass ratio of 20g to 80g, adding 500ml deionized water, uniformly stirring, transferring into a nitrogen oven to dry for 12 hours at 200 ℃, cooling, crushing by using a sand mill, sieving to control the average volume particle size Dv50 of discharged materials to be 4 mu m, and sieving by using a 500-mesh sieve to obtain rosin-based nitrogen-doped powder;

(3) Taking 47.3g of hard carbon crushed aggregates and 52.7g of rosin-based nitrogen-doped powder, uniformly mixing, adding 11g of sodium carboxymethylcellulose, uniformly stirring the mixture, then placing the mixture into a corundum crucible, placing the corundum crucible into a tubular furnace, carbonizing the mixture in an environment with the nitrogen flow of 5L/min, wherein the carbonization temperature is 1500 ℃, the carbonization heat preservation time is 3 hours, taking out the mixture after the internal temperature of the tubular furnace is reduced to room temperature, soaking the mixture into an acetic acid solution, fully stirring, washing the mixture with deionized water to be neutral, drying and grinding the mixture, and then screening the mixture through a 500-mesh screen to obtain the rosin-based nitrogen-doped coated hard carbon cathode material of the sodium ion battery.

Example 10

(1) Firstly weighing 0.4kg of cellulose, 0.5kg of hemicellulose and 0.1kg of lignin, placing the corundum crucible in a corundum crucible, placing the corundum crucible in a heating furnace, preserving heat for 6 hours under the conditions that the nitrogen flow is 1L/min and the heating temperature is 450 ℃, taking out the crucible after the internal temperature of the heating furnace is reduced to room temperature, taking out materials in the crucible, then carrying out jet milling and crushing, sieving, and controlling the average volume particle size Dv50 of discharged materials to be 4 mu m to obtain hard carbon powder;

(2) Putting melamine and gum rosin into a 1000ml beaker according to the mass ratio of 47.3g to 52.7g, adding 500ml deionized water, uniformly stirring, transferring into a nitrogen oven for drying at 200 ℃ for 12h, cooling, then crushing by using a sand mill, sieving to control the average volume particle size Dv50 of the discharged material to be 4 mu m, and sieving the powder by using a 500-mesh sieve to obtain rosin-based nitrogen-doped powder;

(3) Taking 20g of hard carbon crushed aggregates and 80g of rosin-based nitrogen-doped powder, uniformly mixing, then adding 16.5g of sodium carboxymethylcellulose, uniformly stirring the mixture, then placing the mixture into a corundum crucible, placing the corundum crucible into a tubular furnace, carbonizing the mixture in an environment with the nitrogen flow of 5L/min, wherein the carbonization temperature is 1500 ℃, the carbonization heat preservation time is 5 hours, taking out the mixture when the internal temperature of the tubular furnace is reduced to room temperature, soaking the mixture into an acetic acid solution, fully stirring, then washing and filtering the mixture to be neutral by deionized water, drying and grinding the mixture, and then screening the mixture by a 500-mesh screen to obtain the rosin-based nitrogen-doped coated hard carbon cathode material of the sodium ion battery.

And (3) electrochemical performance testing:

the preparation and test method of the half cell comprises the following steps: preparing a polyvinylidene fluoride solution with the mass fraction of 6-7% by taking N-methyl pyrrolidone as a solvent, uniformly mixing the rosin-based nitrogen-doped coated hard carbon negative electrode material of the sodium ion battery prepared in the embodiment 1-10, polyvinylidene fluoride and conductive carbon black according to the mass ratio of 90 to 5, coating the mixture on a copper foil, putting the coated pole piece into a vacuum drying oven at the temperature of 110 ℃ for vacuum drying for 4 hours for later use, and then punching into a small wafer with the diameter of 14 mm. Then transferring the battery to a German Michelona glove box filled with argon to assemble a 2430 type button cell, taking a three-component mixed solvent of 1mol/L NaPF6 as an electrolyte according to the volume ratio of EC: DMC: EMC = 1. FIGS. 1-10 show rosin-based nitrogen-doped coated hard carbon negative electrode materials of sodium ion batteries prepared in examples 1-10

And (3) particle size testing: malvern laser particle size analyzer MS2000;

specific surface area test: kang Da specific surface area NOVA2000e.

The test results are shown in table 1:

TABLE 1

As shown in the data in Table 1, the average volume particle diameter Dv50 of the rosin-based nitrogen-doped coated hard carbon negative electrode material prepared by the method is 4.3-6.1 mu m, and the specific surface area is 4.8-11.7 m ² The first reversible capacity of 0.1C is more than or equal to 320.9mAh/g, the highest reversible capacity can reach 460.4Ah/g, and the first charge-discharge coulombic efficiency of 0.1CMore than or equal to 81.9 percent and can reach 90.3 percent at most.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. A preparation method of a rosin-based nitrogen-doped coated hard carbon negative electrode material of a sodium ion battery is characterized by comprising the following steps: the method comprises the following steps:

(3) Uniformly mixing hard carbon powder and rosin-based nitrogen-doped powder, adding sodium carboxymethylcellulose, and uniformly stirring to obtain a mixture; carbonizing the mixture under an inert atmosphere, cooling, transferring the mixture into an acid solution, stirring, washing, filtering to be neutral, drying, grinding and screening to obtain the rosin-based nitrogen-doped coated hard carbon negative electrode material of the sodium ion battery.

2. The preparation method of the rosin-based nitrogen-doped coated hard carbon negative electrode material for the sodium-ion battery according to claim 1, wherein the preparation method comprises the following steps: in the step (1), the hard carbon material is one or more of cellulose, hemicellulose and lignin.

3. The sodium ion battery rosin-based nitrogen-doped coated hard carbon negative electrode material and the preparation method thereof according to claim 2 are characterized in that: in the step (1), the hard carbon material is cellulose, hemicellulose and lignin, and the mass ratio of the cellulose to the total mass of the hemicellulose and the lignin is 0.1-0.9.

4. The sodium ion battery rosin-based nitrogen-doped coated hard carbon negative electrode material and the preparation method thereof according to claim 1 are characterized in that: in the step (1), the heating temperature is 200-700 ℃, and the heat preservation time is 2-6 h; the average volume particle diameter Dv50 of the hard carbon powder is controlled to be 4-10 mu m, and the specific surface area is 5.4-18.4 m ² /g。

5. The preparation method of the rosin-based nitrogen-doped coated hard carbon negative electrode material for the sodium-ion battery according to claim 1, wherein the preparation method comprises the following steps: in the step (2), the heat treatment is drying for 12 hours at 200 ℃ in a nitrogen atmosphere; the mass ratio of the nitrogen source to the rosin is 0.1-0.9; the average volume particle diameter Dv50 of the rosin-based nitrogen-doped powder is controlled to be 4-10 mu m.

6. The preparation method of the rosin-based nitrogen-doped coated hard carbon negative electrode material for the sodium-ion battery according to claim 5, wherein the preparation method comprises the following steps: the rosin in the step (2) is gum rosin, wood rosin or floating oil rosin; the nitrogen source is one or more of urea, melamine, biuret and aniline.

7. The preparation method of the rosin-based nitrogen-doped coated hard carbon negative electrode material for the sodium-ion battery according to claim 1, wherein the preparation method comprises the following steps: in the step (3), the mass ratio of the hard carbon powder to the rosin-based nitrogen-doped powder is 0.1-0.9, and the mass ratio of the sodium carboxymethylcellulose to the total mass ratio of the hard carbon powder to the rosin-based nitrogen-doped powder is 0.11-0.43.

8. The preparation method of the rosin-based nitrogen-doped coated hard carbon negative electrode material for the sodium-ion battery according to claim 1, wherein the preparation method comprises the following steps: preserving the heat of the carbonized mixture in the step (3) for 2-6 h at the temperature of 900-1500 ℃; the acid solution is acetic acid solution, hydrochloric acid solution, sulfuric acid solution or nitric acid solution.

9. The preparation method of the rosin-based nitrogen-doped coated hard carbon negative electrode material for the sodium-ion battery according to claim 1, wherein the preparation method comprises the following steps: the inert atmosphere is nitrogen gas or argon gas, and the gas flow is 1-5L/min.

10. A rosin-based nitrogen-doped coated hard carbon negative electrode material for a sodium ion battery is characterized in that: the rosin-based nitrogen-doped coated hard carbon negative electrode material for the sodium-ion battery is prepared by the preparation method of the rosin-based nitrogen-doped coated hard carbon negative electrode material for the sodium-ion battery as claimed in any one of claims 1 to 9, wherein the average volume particle size Dv50 of the rosin-based nitrogen-doped coated hard carbon negative electrode material is 4.3 to 6.1 mu m, and the specific surface area of the rosin-based nitrogen-doped coated hard carbon negative electrode material is 4.8 to 11.7m ² The first reversible capacity of 0.1C is more than or equal to 320.9mAh/g, and the first charging and discharging coulombic efficiency of 0.1C is more than or equal to 81.9 percent.