LU600656B1 - A process for producing carbon electrode materials for lithium batteries from balsa wood biomass - Google Patents

Abstract

The present invention discloses a method for producing carbon electrode materials for lithium batteries from balsa wood biomass, which belongs to the technical field of electrode materials for ion batteries and aims at the problems of porous carbon electrode materials having a small number of micropores, a small specific surface area, a high ash content, high impurities, and a low specific lithium storage capacity. The present invention contributes to the production of high-quality porous carbon materials with high added value. In view of the innovation of the carbonization process, the use of two-stage temperature-controlled high-temperature carbonization and the combination of a plurality of pore-forming agents in conjunction with the strategy is conducive to obtaining porous carbon materials with richer micro- and nano-multistage pore structures. Furthermore, the preparation method provided by the present invention is simple, inexpensive, and suitable for industrial mass production, and the porous carbon material prepared by this method has an ultra-high specific surface area, abundant micropores, and low ash, low impurities, high purity, and extremely high specific lithium storage capacity, which is of great significance and value for the development of carbon anode materials for new lithium-ion batteries.

Description

A method for producing carbon electrode materials for LU600656

Lithium batteries made from balsa wood biomass

Technical area

The present invention belongs to the technical field of electrode materials for

Ion batteries and particularly relates to a process for producing carbon

Electrode materials for lithium batteries made from balsa wood biomass.

Technology in the background

Existing porous carbon materials have the advantages of a large specific

Surface, a well-developed micro- and mesoporous pore structure, stable physicochemical properties, are acid and alkali resistant, high temperature resistant, inexpensive and easy to maintain and regenerate, etc., and are widely used in the fields of adsorption, catalytic reaction, and electrochemistry. The porous carbon material with unique microporous-mesoporous multi-level pore structure is receiving more and more attention.

Attention in the application of anode materials for lithium-ion batteries, which is due to the fact that the abundant micropores in this porous

Carbon material has excellent lithium storage performance, while the

Mesopores with relatively large pore size can be used as a channel for the transfer of lithium ions to be rapidly embedded and unembedded, so it may be a more desirable anode material for lithium storage.

China is particularly rich in forest resources, and the amount of forest waste alone amounts to more than 1 billion tons per year. Compared to porous carbon on

Coal-based, the use of forest products and their waste to produce porous wood-based carbon has the advantages of a broad raw material source, low

Carbon emissions and low prices. Its industrial development is highly consistent with the national dual-carbon strategy and can promote the green transformation of carbon-carbon, which is of great significance and value for the energy and

environmental sustainability is.

Tree biomass is a rich raw material for the production of porous

Carbon materials. Balsa wood is the fastest growing and lightest tree in the

Nature, and compared to other trees, balsa wood itself has a high specific area and developed micro-nano pore structure, which is a very ideal raw material for the production of porous carbon materials. The present invention selects balsa wood and its "three residues" as a carbon source, utilizes its naturally rich pore structure, and through the

Using pore former and activator to make further pores and activation, it can prepare high-quality, high-quality wood porous carbon materials.

Existing porous carbon electrode materials have a small number of

Micropores, a small specific surface area, a high ash content, many impurities, low purity and a low specific lithium storage capacity.

Therefore, there is a need for a process for the production of

Carbon electrode materials for lithium batteries from balsa wood biomass to solve the problems of existing porous carbon electrode materials with a small number of

Micropores, a small specific surface area, a high ash content, a high number of impurities, low purity and low lithium storage capacity in

state of the art.

Content of the invention

One of the aims of the present invention is to provide a process for the preparation vdi/600656

To provide carbon electrode materials for lithium batteries from balsa wood biomass, wherein the produced porous material has a large specific surface area, low

ash content, a stable nature and high added value. One of the aims of the present invention is to provide a carbon electrode material for lithium batteries from

Balsa wood biomass, which has abundant micropores and a unique microporous-mesoporous multi-level pore structure. The size of the micropores corresponds to the spatial size of the lithium-ion storage and has a high specific lithium

Storage capacity, while the Me

To achieve the above-mentioned purpose, the present invention provides the following technical solution:

S1, Selection of balsa wood and its three residues as biomass carbon source,

Cleaning to remove impurities on the surface, and drying and crushing as carbon source raw material for producing porous negative

Carbon electrode materials;

S2, The crushed balsa wood is pre-carbonized, dried to remove water, and naturally cooled to room temperature to obtain a pre-carbonized product;

S3, The pre-carbonized product and the pore-forming agent are homogeneously mixed and ground, and the material is then transferred to a high-temperature tube furnace for two-stage temperature-controlled high-temperature carbonization under an atmosphere of N2 or Ar gas, and naturally cooled and ground;

S4, The two-stage high-temperature carbonization product is washed with acid and washed with water until neutral, the impurities present in the material are removed, and the material is pumped and dried to obtain a porous carbon material with a microporous and mesoporous multi-stage pore structure;

SS, The porous carbon material is stirred and mixed with a conductive agent and a

Binder is dispersed in a solvent to form an anode slurry, and then the slurry is applied to an anode collector and dried and cut to obtain a lithium-ion battery carbon anode.

Preferably, the three residual materials in S1 are sawdust, bark and chips.

In S2, the pre-carbonization temperature is preferably 150-200 °C, the

Temperature increase rate 5-10 °C/min and pre-carbonization time 4-10 hours.

Preferably, in S3, the pore-forming agent used is two or more of KOH,

KHCO3, Li2CO3, CaCO3, and the weight ratio of the pre-carbonization product to

Pore forming agent is 1: 0.1-0.3.

Preferably, in S3, the temperature of the first carbonization stage is 500-700°C and the carbonization time is 6-10h; the temperature of the second carbonization stage is 800-1000°C and the carbonization time is 1-4h.

Preferably in S4 the acid used in the pickling process is one or both of HCl, H3PO4.

Preferably in SS the conductive agent and the binder are acetylene black and acetylene black respectively.

Polyvinylidene fluoride, wherein the weight ratio of the porous carbon material, the

Acetylene black and polyvinylidene fluoride is 1:0.05-0.1:0.05-0.1 and is mixed homogeneously.

Preferably, the porous carbon material produced in SS has a specific

Surface area of more than 1800 m*/g, pore size is mainly distributed between 0.1 and 6 nm, and the percentage of microporous volume of 0.5-1 nm is more than 50%. LU600656

Preferably, the produced carbon anode for lithium-ion batteries has a specific lithium storage capacity of 3400 mAh/g, a charge/discharge multiplication rate of 0.1-3 C and a cycle life of more than 2000 times.

The present invention also provides a carbon electrode material for

Lithium batteries made from balsa wood biomass are available, which is produced using the

Process for the production of carbon electrode materials for lithium batteries from

Balsa wood biomass is produced.

Compared to the prior art, the present invention provides a method for

Production of carbon electrode materials for lithium batteries from balsa wood biomass, which has at least the following advantageous effects:

Regarding the screening of the biomass carbon source, the use of

Balsa wood, which has its own natural advantages such as high specific area and well-developed microporous structure, as a carbon source conducive to the production of high-quality porous carbon materials with high added value; As for the innovation of the

Carbonization process, the use of a two-stage temperature-controlled high-temperature carbonization and the combination of different pore-forming agents in the bonding strategy is conducive to obtaining porous

Carbon materials with richer micro- and nano-multilevel pore structures.

Furthermore, the manufacturing process according to the invention is simple, cost-effective and suitable for industrial mass production. The porous

Carbon material has an ultra-high specific surface area, abundant micropores, low ash, few impurities, high purity and extremely high specific lithium

storage capacity, which is important for the development of carbon anode materials for new lithium

Ion batteries are of great importance and value.

Description of the attached drawings

Figure 1 is a BET test result of the porous carbon material prepared in Embodiment 1 of the present invention, wherein: (a) pore size distribution diagram; (b) isothermal adsorption curve;

Figure 2 is a charge and discharge cycle curve of the negative electrode material used in

Embodiment 1 of the present invention was prepared: charge and discharge current density of 100 mA/g (left image); charge and discharge current density of 1000 mA/g (right image);

Figure 3 is a charge/discharge cycle diagram of the negative electrode material used in

Embodiment 2 of the present invention was prepared: Charge/discharge current density 100

MmA/g (left image); charge/discharge current density 500 mA/g (right image);

Figure 4 is a graph of the multiplicity performance of the negative electrode material used in

Embodiment 3 of the present invention: (a) Multiplicity cycle curve, (b) Charge-discharge curve;

Figure 5 is a diagram of the charge-discharge cycle curve (500mA/g) of the negative

Electrode material prepared in Embodiment 4 of the present invention.

Detailed description

The technical solutions in the embodiments of the present invention are described in

The following will be clearly and completely described in connection with the embodiments of the present invention, and it is obvious that the described embodiments represent only a part of the embodiments of the present invention and not all embodiments. Starting from the embodiments of the present invention, other embodiments that a person skilled in the art can produce without creative work also fall within the scope of the invention.

Scope of the present invention.

Embodiment 1

S1, Balsa wood is selected as a biomass carbon source and cleaned with deionized water to remove impurities on the surface, and is dried and crushed as …— carbon source raw material for the production of = porous

Carbon anode materials;

S2, The crushed carbon source raw material is pre-carbonized under the atmosphere of air, with a pre-carbonization temperature of 180°C, a

Temperature increase rate of 5°C/min, a pre-carbonization time of 6h, and a

Pre-carbonization product is obtained by natural cooling to room temperature;

S3, The pre-carbonization product was uniformly treated with four kinds of pore-forming

agents, namely KOH, KHCO3, Li2CO3 and CaCO3, mixed and ground, and the

The weight ratio of the pre-carbonization product to the pore-forming agent was 1:0.3.

Then, the product was subjected to high-temperature carbonization under the atmosphere of Ar gas, and the first stage of carbonization was carried out at a carbonization temperature of 550 °C and a carbonization time of 7 h. The pre-carbonization product was then cooled to room temperature; the second stage of carbonization with a

Temperature of 900 C, a carbonization time of 2 hours and natural cooling to room temperature to obtain a high-temperature carbonization product;

S4, The two-stage high-temperature carbonization product is washed with hydrochloric acid and washed to neutrality, the impurities present in the material are removed, filtered and dried, and the porous carbon material is obtained;

S5, The porous carbon material is homogeneously coated with acetylene black and

Polyvinylidene fluoride is mixed in a weight ratio of 1:0.1:0.1, and water is added and stirred to obtain a lithium-ion battery carbon anode slurry, and then the slurry is applied to an anode collector, dried, and cut into pieces to obtain a lithium-ion battery carbon anode.

Embodiment 2

S1, The three residues of balsa wood (sawdust, bark and chips, etc.) are used as biomass

Carbon source is selected and cleaned with deionized water to remove impurities on the surface, and are dried and pulverized as a carbon source raw material for the preparation of a porous negative carbon electrode material;

S2, The crushed carbon source raw material is pre-carbonized under the atmosphere of air, with a pre-carbonization temperature of 180°C, a

Temperature increase rate of 5°C/min, a pre-carbonization time of 6h, and a

Pre-carbonization product is obtained by natural cooling to room temperature;

S3, The pre-carbonization product was homogeneously mixed and ground with KOH, KHCO3, Li2CO3 and CaCO3 as pore formers, and the weight ratio of the

pre-carbonization product to the pore former was 1:0.2. Then the

High-temperature carbonization was carried out under Ar gas atmosphere, with the temperature of the first stage of carbonization being 650°C and the carbonization time being 7 hours; the

The temperature of the second stage of carbonization was 800°C and the carbonization time was 2

hours, and the high-temperature carbonized product was obtained by natural cooling to room temperature; LU600656

S4, The two-stage high-temperature coking product is washed with hydrochloric acid and washed to neutrality, the impurities present in the material are removed, and the porous carbon material is obtained by pumping and drying; 5 SS, The porous carbon material is evenly coated with acetylene black and

Polyvinylidene fluoride is mixed in a weight ratio of 1:0.1:0.1, and water is added and stirred to obtain a lithium ion battery carbon anode slurry, and then the slurry is applied to the anode collector and dried and cut to obtain a lithium ion battery carbon anode.

Embodiment 3

S1, The three residues of balsa wood (sawdust, bark and chips, etc.) were used as biomass

Carbon source selected and cleaned with deionized water to remove impurities on the surface, and were dried and pulverized as carbon source

Raw material for the production of the porous carbon anode material;

S2, The crushed carbon raw material is pre-carbonized under the atmosphere of air, with a pre-carbonization temperature of 180°C, a

Temperature increase rate of 5°C/min, a pre-carbonization time of 6h, and a

Pre-carbonization product is obtained by natural cooling to room temperature;

S3, The pre-carbonization product is uniformly treated with three types of pore-forming

agents, namely KOH, KHCO3 and CaCO3, and the weight ratio of the pre-carbonization product and the pore-forming agent is 1:0.3. Then the

High-temperature carbonization was carried out under the atmosphere of Ar gas, and the first

The carbonization stage is carried out at a carbonization temperature of 550°C for a

Carbonation time of 7h; the second stage of carbonation is carried out at a

Carbonization temperature of 900°C for a carbonization time of 2h, and the

High-temperature carbonization product is obtained by natural cooling to room temperature;

S4, The two-stage high-temperature carbonization product is acid-washed with hydrochloric acid and washed to neutrality, the impurities present in the material are removed, filtered and dried, and the porous carbon material is obtained;

SS, The porous carbon material is evenly coated with acetylene black and

Polyvinylidene fluoride is mixed in a weight ratio of 1:0.1:0.1, and water is added and stirred to obtain a lithium ion battery carbon anode slurry, and then the slurry is applied to an anode collector, dried and cut, and the lithium ion battery carbon anode is obtained.

Embodiment 4

S1, The three residues of balsa wood (sawdust, bark and chips, etc.) were used as biomass

Carbon source selected and cleaned with deionized water to remove impurities on the surface, and were dried and pulverized as carbon source

Raw material for the production of the porous carbon anode material;

S2, The crushed carbon raw material is pre-carbonized under the atmosphere of air, with a pre-carbonization temperature of 180°C, a

Temperature increase rate of 5°C/min, a pre-carbonization time of 6h, and a

Pre-carbonization product is obtained by natural cooling to room temperature;

S3, The pre-carbonization product is uniformly treated with three types of pore-forming

agents, namely KOH, KHCO3 and CaCO3, and the weight ratio of the pre-carbonization product and the pore-forming agent is 1:0.3. Then the

High-temperature carbonization was carried out under the atmosphere of Ar gas, and the first

The first stage is carbonized at a temperature of 550°C for a carbonization time of 7h; the second stage is carbonized at a temperature of 900°C for a carbonization time of 2h, and the high-temperature carbonization product is obtained by natural cooling to room temperature;

S4, The two-stage high-temperature coke product is washed with hydrochloric acid and washed to neutrality, the impurities present in the material are removed, and the porous carbon material is obtained by pumping and drying;

SS, The porous carbon material is evenly coated with acetylene black and

Polyvinylidene fluoride is mixed in a weight ratio of 1:0.1:0.1, and water is added and stirred to obtain a lithium ion battery carbon anode slurry, and then the slurry is applied to an anode collector and dried and cut into pieces to obtain a lithium ion battery carbon anode.

In summary, the present embodiment provides a lithium-ion battery

Half-cell is prepared, in which the prepared electrode plate is compressed with a press and the

Diaphragm is selected as a fiberglass disc with a diameter of 19 mm. The

Electrolyte is selected as 1 mol/LLiPF6/EC/DMC/EMC, and the CR2032 button cell is stored in a glove box in a high purity argon atmosphere with the lithium foil as

Counter electrode assembled, and the CR2032 button cell is left for 5 hours to perform a charge/discharge test of the cell in a Blaupunkt test platform under

Using current densities of 100mA/g and 500mA/g.

Figures 1(a) and (b) show the pore size distribution and the isothermal

Adsorption curves of the porous material prepared in Embodiment 1 of the present invention

Carbon material. According to the BET test results, the specific surface area of the produced porous carbon material is 2240 m?/g or more; the pore size of the porous

The carbon material is mainly microporous and smaller than 1 nm, with a volume fraction of more than 60%. There are also micropores of 1-2 nm and mesopores of 2-3 nm and 4-6 nm, which represents a multi-level microporous and mesoporous structure of the porous carbon material. The large microporous volume can accommodate more lithium ions, and the

Mesopores can be used as channels for the diffusion transport of lithium ions for rapid embedding and deembedding.

Figure 2 shows the charge and discharge cycle curves of the battery manufactured in embodiment 1.

anode material at current densities of 100 and 1000 mA/g. The charging capacity at a

Current density of 100 mA/g is up to 600 mAh/g, and there is almost no deterioration of the

Capacity at 700 stable cycles; when charging at a high current density of 1000 mA/g, the specific capacity is still 400 mAh/g or more, and the capacity retention rate at 2,500 cycles is 90% or more, which has excellent fast charging potential and high

shows cycle stability.

Figure 3 shows the charge and discharge cycle curves of the negative electrode material prepared in embodiment 2 at a current density of 100 and 500 mA/g, respectively.

Current density of 100 mA/g, the specific capacity of the first charge can reach more than 780 mAh/g, and the specific capacity can be maintained at about 590 mAh/g even after more than 200 cycles; When charging with a higher current density of 500 mA/g, the specific

The capacity of the first charge can reach more than 510 mAh/g, and after more than 1000 charging cycles/600656, the specific capacity can still be maintained at about 500 mAh/g.

Figure 4 shows the negative electrode material prepared in Embodiment 3, and Figure 3 shows the multi-cycle curve and the corresponding charge/discharge curve of the negative electrode material prepared in Embodiment 2. The specific capacities at current densities of 50, 100, 500, 1000, 2000, and 5000 mA/g are approximately: 670 mAh/g, 560 mAh/g, 450 mAh/g, 320 mAh/g, 280 mAh/g, and 200 mAh/g, respectively. When the current density decreases to 50 mA/g, the specific capacity approaches the initial specific capacity, demonstrating excellent

shows multiplication performance.

Figure 5 shows the charge/discharge cycle curve of the battery manufactured in embodiment 4.

Anode material. The specific capacity of the anode is up to 400 mAh/g at a

Current density of 500 mA/g, which is significantly higher than that of various commercial

Carbon-based anode materials that still have a high specific

capacity of 380 mAh/g. The capacity retention rate is over 95% and the

Coulomb efficiency at 100%, which indicates excellent capacity and cycle stability.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that numerous changes, modifications,

Substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is limited by the appended claims and their equivalents.

Claims (10)

Claims LU600656 1. A method for producing carbon electrode materials for lithium batteries from balsa wood biomass, characterized in that it comprises the following steps: S1, selecting balsa wood and its three residues as a carbon source from biomass, purifying to remove surface impurities, drying, and crushing as a carbon source raw material for producing porous negative carbon electrode materials; S2, the crushed balsa wood is pre-carbonized, dried to remove water, and naturally cooled to room temperature to obtain a pre-carbonized product; S3, the pre-carbonized product and the pore-forming agent are homogeneously mixed and ground, and the material is then transferred to a high-temperature tube furnace for two-stage temperature-controlled high-temperature carbonization under an atmosphere of N2 or Ar gas, and naturally cooled and ground; S4, The two-stage high-temperature carbonization product is washed with acid and washed with water until neutral, the impurities present in the material are removed, and the material is pumped and dried to obtain a porous carbon material having a microporous and mesoporous multi-stage pore structure; SS, The porous carbon material is stirred and dispersed with a conductive agent and a binder in a solvent to form an anode slurry, and then the slurry is coated on an anode collector and dried and cut to obtain a lithium-ion battery carbon anode. 2. A method for producing carbon electrode materials for lithium batteries from balsa wood biomass according to claim 1, characterized in that: in S1 the three residues are sawdust, bark and chips, etc. 3. A method for producing carbon electrode materials for lithium batteries from balsa wood biomass according to claim 1, characterized in that: in S2 the pre-carbonization temperature is 150-200°C, the temperature increase rate is 5-10°C/min and the pre-carbonization time is 4-10h. 4. A method for producing carbon electrode materials for lithium batteries from balsa wood biomass according to claim 1, characterized in that: in S3, the pore-forming agent used is two or more of KOH, KHCO3, Li2CO3, CaCO3, and the weight ratio of the pre-carbonization product to the pore-forming agent is 1: 0.1-0.3. 5. A method for producing carbon electrode materials for lithium batteries from balsa wood biomass according to claim 1, characterized in that: in S3, the temperature of the first carbonization stage is 500-700°C and the carbonization time is 6-10 hours; the temperature of the second carbonization stage is 800-1000°C and the carbonization time is 1-4 hours. 6. A process for producing carbon electrode materials for lithium batteries from balsa wood biomass according to claim 1, characterized in that: in S4 the acid used in the pickling process is one or both of the acids HCl, H3PO4. 7. A method for producing carbon electrode materials for lithium batteries from balsa wood biomass according to claim 1, characterized in that: in S5, the conductive agent and the binder are acetylene black and polyvinylidene fluoride, respectively, wherein the weight ratio of the porous carbon material, the acetylene black and the Polyvinylidene fluoride 1:0.05-0.1:0.05-0.1 is homogeneously mixed. LU600656 8. A method for producing carbon electrode materials for lithium batteries from balsa wood biomass according to claim 1, characterized in that: the produced porous carbon material in S5 has a specific surface area of more than 1800 m?/g, the pore size is mainly distributed between 0.1 and 6 nm, and the percentage of the volume of micropores of 0.5-1 nm is more than 50%. 9. A method for producing carbon electrode materials for lithium batteries from balsa wood biomass according to claim 1, characterized in that the produced carbon anode for a lithium-ion battery has a specific lithium storage capacity of = 400mAh/g, a charge/discharge multiplication rate of 0.1-3C and a cycle life of more than 2000 times. 10. A carbon electrode material for lithium batteries made from balsa wood biomass, characterized in that it is produced according to the process for producing the carbon-containing electrode material for lithium batteries made from balsa wood biomass described in claims 1 to 9.