CN111146423B

CN111146423B - Pre-lithiated binary topological structure phosphorus/carbon composite material and preparation method and application thereof

Info

Publication number: CN111146423B
Application number: CN201911376368.7A
Authority: CN
Inventors: 孙洁; 刘成; 向黔新; 周朝毅; 李路; 胡安生; 武阳; 王丽娟
Original assignee: Guizhou Zhenhua Yilong E Chem Co ltd; Tianjin University; Guizhou Zhenhua New Material Co Ltd
Current assignee: Guizhou Zhenhua Yilong E Chem Co ltd; Tianjin University; Guizhou Zhenhua New Material Co Ltd
Priority date: 2019-12-27
Filing date: 2019-12-27
Publication date: 2023-05-16
Anticipated expiration: 2039-12-27
Also published as: CN115084465A; CN115188936A; CN115332493A; CN115188935B; CN111146423A; CN115332493B; CN115188936B; CN115188935A; CN115084465B

Abstract

The invention provides a pre-lithiated binary topological structure phosphorus/carbon composite material which is lithiated x-dimensional phosphorus/y-dimensional carbon, wherein x and y are integers, x is more than or equal to 0 and less than or equal to 3, and y is more than or equal to 1 and less than or equal to 3. The invention also provides four preparation methods of the pre-lithiated binary topological structure phosphorus/carbon composite material: (1) The elemental phosphorus is limited to the carbon-based material and then lithiated. (2) The method comprises the steps of carrying out lithiation treatment on the carbon-based material, and then confining phosphorus to the carbon-based material. (3) The phosphorus is lithiated and then confined to the carbon-based material. (4) Firstly, directly mixing a phosphorus source and a conductive carbon material in a ball milling or hand milling mode, and then carrying out lithiation treatment. The pre-lithiated binary topological structure phosphorus/carbon composite material prepared by the invention has high theoretical specific capacity and higher conductivity, and also ensures high first coulombic efficiency.

Description

Pre-lithiated binary topological structure phosphorus/carbon composite material and preparation method and application thereof

Technical Field

The invention belongs to the field of lithium ion battery electrode materials, and particularly relates to preparation and application of a pre-lithiated binary topological structure phosphorus/carbon composite material.

Background

Lithium ion batteries have emerged in many secondary battery systems due to their relatively high energy density, and have successfully occupied the portable electronic device market in as little as twenty years. However, with the rise of some new energy storage devices, such as power cells and stationary energy storage power stations, new demands are being placed on the development of secondary batteries. Power cells are required to have not only high energy density but also high rate capability and safety performance. However, graphite, which is a cathode material of a lithium ion battery, is mainly commercialized at present, and is easy to form 'lithium dendrite' under high current density due to low electrode potential, so that potential safety hazards are caused. While a spinel structure Li with "zero strain ₄ Ti ₅ O ₁₂ Due to its higher electrode potential (1.5V vs Li/Li ⁺ ) The lithium dendrite is not easy to form in the charge and discharge process, and the safety performance is high, which brings great attention to people. However, its low theoretical specific capacity (175 mAh/g) limits its wide application in lithium ion batteries. Phosphorus is used as an emerging anode material, has the advantages of low price, abundant reserves, environmental friendliness, high specific capacity and the like, and gradually develops into the key point of anode research. In addition, compared with silicon (0.4V vs Li/Li ⁺ ) Graphite (0.1V vs Li/Li) ⁺ ) Negative electrode with higher electrode potential (0.7V vs Li/Li) ⁺ ) High-rate charge-discharge strip for power batterySafety under the piece. However, the problems of poor phosphorus conductivity and large volume changes during charge and discharge limit the development of phosphorus.

Phosphorus has a variety of allotropes: white phosphorus, amorphous red phosphorus, violet phosphorus, fibrous phosphorus, black phosphorus and blue phosphorus, wherein the application of the amorphous red phosphorus, the amorphous black phosphorus and the amorphous blue phosphorus in the anode material of the lithium ion battery has been proved in experiments or theoretical calculation. In recent years, researchers have made a great deal of scientific research to develop the advantage of high theoretical specific capacity of phosphorus, and mainly concentrate on compounding red phosphorus or black phosphorus with a carbon-based material with good conductivity, and various phosphorus/carbon binary topological structures can be formed according to different dimensions (D) and combination modes of phosphorus and carbon. For example Liu Cheng, in the "design of a phosphorus-carbon binary topology and its application in the energy storage field" (energy storage science and technology, seventh volume, sixth period), a phosphorus-carbon binary topology is introduced, including red phosphorus/carbon binary topologies 0D/0D, 0D/1D, 1D/1D, 0D/2D, 2D/2D, 0D/3D and black phosphorus/carbon binary topologies 0D/0D, 0D/1D, 2D/2D, in chinese patent publication No. CN109148870a, graphite and nanotubes after surface oxidation and freeze drying treatment are used as a base material, mixed and sealed with red phosphorus solid powder, and baked at high temperature, so that red phosphorus is effectively filled into the layer spacing of the base material, and a 0D (red phosphorus)/2D (carbon) structure is formed, and these phosphorus-carbon binary topologies can effectively improve the conductivity of the electrode material, alleviate the problem of collapse and pulverization of the structure caused by volume change during lithium ion charging and discharging, improve the cycling stability of the phosphorus negative electrode, but the cycle efficiency is lower than that the first charge and discharge efficiency is still to be higher than the further to be required.

Disclosure of Invention

Aiming at the technical problems of high-rate charge-discharge cycling stability, low first coulombic efficiency and the like of the current lithium ion battery phosphorus-based composite anode material, the inventor designs a phosphorus-carbon binary topological structure with a finite field effect and a modification mode through long-term research, and aims to improve the first coulombic efficiency and the high-rate charge-discharge performance of the phosphorus-based anode material.

Therefore, the invention provides a pre-lithiated binary topological structure phosphorus/carbon composite material which is lithiated x-dimensional phosphorus/y-dimensional carbon, wherein x and y are integers, x is more than or equal to 0 and less than or equal to 3, and y is more than or equal to 1 and less than or equal to 3.

The prelithiated binary topology phosphorus/carbon composite material described above, wherein the phosphorus is amorphous red phosphorus, violet phosphorus, fibrous phosphorus, black phosphorus or blue phosphorus.

The pre-lithiated binary topology phosphorus/carbon composite material according to above, wherein the carbon is a one-dimensional tubular carbon-based material, a two-dimensional layered carbon-based material, or a 3-dimensional porous carbon material.

The invention also provides a preparation method of the pre-lithiated binary topological structure phosphorus/carbon composite material, which comprises the following steps:

(c) Coating a phosphorus source by using a coating material, and then carbonizing at high temperature to obtain x-dimensional phosphorus/y-dimensional carbon with a binary topological structure, wherein x and y are integers, x is more than or equal to 0 and less than or equal to 3, and y is more than or equal to 1 and less than or equal to 3;

(d) And (c) carrying out lithiation treatment on the binary topological structure x-dimensional phosphorus/y-dimensional carbon obtained in the step (a) by using a lithium source.

According to the preparation method, the coating material is a substance which forms a carbon or nitrogen doped carbon-based material after pyrolysis.

According to the preparation method, the coating material is an organic amine compound.

According to the preparation method, the coating material is dopamine.

According to the preparation method, the phosphorus source is elemental phosphorus or a compound which can form stable elemental phosphorus after pyrolysis.

The preparation method according to the above, wherein the phosphorus source is a phosphorus oxide compound.

The preparation method comprises the step of preparing phosphorus source phosphorus pentoxide.

The preparation method according to the above, wherein the carbonization temperature is 300-1000 ℃.

The preparation method according to the above, wherein the carbonization temperature is 350-800 ℃.

The preparation method according to the above, wherein the carbonization temperature is 500-700 ℃.

According to the preparation method, the mass ratio of the lithium source to the phosphorus source is 1:1-1:200.

The preparation method comprises the steps of preparing lithium foil, lithium powder, molten lithium, inorganic lithium salt or Li-organic compound solution.

The preparation method is characterized in that the lithiation treatment temperature is 180-400 ℃.

According to the preparation method, the mass ratio of the phosphorus source to the coating material is 3:1-30:1.

The invention also provides a second preparation method of the pre-lithiated binary topological structure phosphorus/carbon composite material, which comprises the following steps:

(a) Placing a phosphorus source and a carbon-based material into two heating temperature areas of a tubular furnace chamber for heating to obtain x-dimensional phosphorus/y-dimensional carbon with a binary topological structure, wherein x and y are integers, x is more than or equal to 0 and less than or equal to 3, and y is more than or equal to 1 and less than or equal to 3;

(b) And (c) carrying out lithiation treatment on the binary topological structure x-dimensional phosphorus/y-dimensional carbon obtained in the step (a) by using a lithium source.

According to the preparation method, the phosphorus source is red phosphorus.

The preparation method according to the above, wherein the carbon-based material is graphite, expanded graphite, graphite acid or porous carbon.

According to the preparation method, the mass ratio of the phosphorus source to the carbon source is 3:1-30:1.

According to the above preparation method, wherein the heating temperature of the phosphorus source is 400-500 ℃ and the heating temperature of the carbon-based material is 200-350 ℃.

The invention also provides a third preparation method of the pre-lithiated binary topological structure phosphorus/carbon composite material, which comprises the following steps:

(a) Mixing a carbon-based material with a lithium source, and carrying out lithiation treatment on the carbon-based material by using the lithium source to obtain a lithiated carbon-based material;

(b) And (c) mixing and heating the lithiated carbon-based material obtained in the step (a) and a phosphorus source to obtain the pre-lithiated binary topological structure phosphorus/carbon composite material.

The preparation method according to the above, wherein the carbon-based material is graphite, expanded graphite or porous carbon.

The production method according to the above, wherein the carbon-based material is expanded graphite.

According to the preparation method, the phosphorus source is elemental phosphorus.

According to the preparation method, the mass ratio of the phosphorus source to the carbon source is 1:2-10:1.

The preparation method is characterized in that the lithiation treatment temperature is 200-800 ℃.

The preparation method is characterized in that the lithiation treatment temperature is 200-500 ℃.

The production method according to the above, wherein the heating temperature in the step (b) is 200 to 400 ℃.

The preparation method according to above, wherein the heating time in step (b) is 1-4hr.

The invention also provides a fourth preparation method of the pre-lithiated binary topological structure phosphorus/carbon composite material, which comprises the following steps:

(a) Mixing a phosphorus source and a lithium source, and carrying out lithiation treatment on the phosphorus source by using the lithium source to obtain a lithium phosphide material;

(b) And (c) mixing and heating the lithium phosphide material obtained in the step (a) and a carbon-based material to obtain the pre-lithiated binary topological structure phosphorus/carbon composite material.

The preparation method comprises the step of preparing a lithium source, wherein the lithium source is a lithium foil.

The preparation method is characterized in that the lithiation treatment temperature is 200-400 ℃.

The preparation method according to the above, wherein the carbon-based material is expanded graphite or graphite acid.

According to the preparation method, the mass ratio of the phosphorus source to the carbon source is 1:1-20:1.

The invention also provides a fifth preparation method of the pre-lithiated binary topological structure phosphorus/carbon composite material, which comprises the following steps:

(a) The phosphorus source and the conductive carbon material are directly mixed by ball milling or hand milling.

(b) And (c) mixing and heating the phosphorus-carbon composite material obtained in the step (a) with a lithium source to obtain the pre-lithiated binary topological structure phosphorus/carbon composite material.

The preparation method comprises the steps of preparing the carbon-based material from graphite, porous carbon, activated carbon and carbon nano tubes.

The preparation method according to the above, wherein the carbon-based material is a carbon nanotube.

According to the preparation method, the mass ratio of the phosphorus source to the carbon source is 1:1-15:1.

The preparation method is characterized in that the lithiation treatment temperature is 300-500 ℃.

The invention also provides a lithium ion battery cathode, and the active substance of the lithium ion battery cathode is the pre-lithiated binary topological structure phosphorus/carbon composite material.

The invention also provides a lithium ion battery, which comprises the lithium ion battery cathode.

The invention has the beneficial effects that: (1) Compared with the binary topological structure phosphorus/carbon composite material, the pre-lithiated binary topological structure phosphorus/carbon composite material prepared by the invention has high theoretical specific capacity and higher conductivity. (2) In the pre-lithiation process, the surface of the elemental phosphorus and the surface of the carbon substrate material form materials such as lithium phosphide, lithium oxide or lithium nitride with high ion conductivity, and the SEI film components are optimized. (3) Compared with the binary topological structure phosphorus/carbon composite material, the pre-lithiation is equivalent to one-time lithium supplementing process of the negative electrode, and high first coulombic efficiency is ensured.

Drawings

FIG. 1 is a TEM image (20 thousand times) of a binary topology phosphorus/carbon composite material in example 1 of the present application;

FIG. 2 is an XRD pattern of a pre-lithiated binary topology phosphorus/carbon composite material obtained in example 3 of the present application;

FIG. 3 is an SEM image (5 ten thousand times) of a pre-lithiated binary topology phosphorus/carbon composite material obtained in example 3 of the present application;

FIG. 4 is an SEM image (3 ten thousand times) of a pre-lithiated binary topology phosphorus/carbon composite material obtained in example 4 of the present application;

fig. 5 is a schematic diagram of a pre-lithiated binary topology phosphorus/carbon composite material obtained in example 7 of the present application.

Detailed Description

The invention firstly provides a pre-lithiated binary topological structure phosphorus/carbon composite material, which is lithiated x-dimensional phosphorus/y-dimensional carbon, wherein x and y are integers, x is more than or equal to 0 and less than or equal to 3, and y is more than or equal to 1 and less than or equal to 3. The phosphorus comprises amorphous red phosphorus, violet phosphorus, fibrous phosphorus, black phosphorus and blue phosphorus. The carbon includes one-dimensional tubular carbon-based material, two-dimensional layered carbon-based material, or 3-dimensional porous carbon material.

The invention also provides four preparation methods of the pre-lithiated binary topological structure phosphorus/carbon composite material: (1) The elemental phosphorus is limited to the carbon-based material and then lithiated. (2) The method comprises the steps of carrying out lithiation treatment on the carbon-based material, and then confining phosphorus to the carbon-based material. (3) The phosphorus is lithiated and then confined to the carbon-based material. (4) Firstly, directly mixing a phosphorus source and a conductive carbon material in a ball milling or hand milling mode, and then carrying out lithiation treatment. In the preparation method (1), the method for limiting the elemental phosphorus to the carbon-based material to form the phosphorus-carbon binary topological structure comprises two modes: coating a phosphorus source in a 'top-down' mode, and then carbonizing at a high temperature; (II) a "bottom-up" approach, i.e., the incorporation of elemental phosphorus into the carbon-based material.

In the above method, the lithium source used for the lithiation treatment is a lithium foil, lithium powder, molten lithium, inorganic lithium salt or Li-organic composite solution. The phosphorus source is elemental phosphorus or a compound which can form stable elemental phosphorus after pyrolysis. The carbon-based material is graphite, expanded graphite, graphite acid or porous carbon.

In the method (1) (I), the dosage ratio of the lithium source to the phosphorus source is 1:1-1:200 according to the mass ratio of lithium to phosphorus element, and the mass ratio of the phosphorus source to the coating material is 3:1-30:1 according to the mass ratio of phosphorus to carbon element. The lithiation treatment temperature is 180-400 ℃. The coating material is a substance which forms a carbon or nitrogen doped carbon-based material after pyrolysis; the carbonization temperature is 300-1000 ℃.

Preferably, the phosphorus source is a phosphorus oxide compound, the coating material is one or more of organic amine compounds, and the carbonization temperature is 350-800 ℃.

More preferably, the phosphorus source is P ₂ O ₅ Or red phosphorus, wherein the coating material is dopamine, and the carbonization temperature is 500-700 ℃.

In the method (1) (II), a phosphorus source and a carbon-based material are placed in two heating temperature areas of the same tubular furnace chamber for heating, the heating temperature of the phosphorus source is 400-500 ℃, the heating temperature of the carbon-based material is 200-350 ℃, the two materials react to obtain x-dimensional phosphorus/y-dimensional carbon with a binary topology structure, and then the two materials are lithiated by a lithium source, wherein the lithiation treatment temperature is 180-400 ℃.

In method (2), the carbon-based material is graphite, expanded graphite, or porous carbon; the lithiation treatment temperature is 200-800 ℃; the phosphorus source is elemental phosphorus and a compound of elemental phosphorus or phosphorus oxide which can be formed after pyrolysis.

Preferably, the carbon-based material is expanded graphite; the lithiation temperature is 200-500 ℃; the phosphorus source is elemental phosphorus.

In the method (3), the phosphorus source is elemental phosphorus, the lithiation temperature is 20-800 ℃, and the carbon-based material is expanded graphite or graphite acid.

Preferably, the lithium source is a lithium foil; the dosage ratio of the lithium source to the phosphorus source is 1:1-1:200, and the lithiation treatment temperature is 200-400 ℃; the carbon-based material is expanded graphite.

In the method (4), the phosphorus source is elemental phosphorus or a compound which can form stable elemental phosphorus after pyrolysis, preferably elemental phosphorus; the carbon-based material is graphite, porous carbon, activated carbon, carbon nanotubes, preferably carbon nanotubes; the lithium source is lithium foil, lithium powder, molten lithium, inorganic lithium salt or Li-organic compound solution, preferably lithium foil; the mass ratio of the phosphorus source to the carbon source is 1:1-15:1, and the mass ratio of the lithium source to the phosphorus source is 1:1-1:200; the lithiation temperature is 200-800 ℃, preferably 300-500 ℃.

In order to more clearly illustrate the present invention, the present invention will be further described with reference to preferred embodiments and the accompanying drawings. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and that this invention is not limited to the details given herein.

The instrument models and parameter conditions used in the following examples are as follows:

XRD: adopting a BrookD 8-Focus X-ray diffractometer, wherein the test range is 20-70 degrees, and the scanning rate is 5 degrees/min;

TEM: adopting a JEM-2100 Transmission Electron Microscope (TEM);

SEM: hitachi S-4800 Scanning Electron Microscope (SEM) was used.

Example 1:

1g of red phosphorus is taken in a 250mL four-necked flask, 150mL of 2mg/mL dopamine solution (the solvent is Tris (hydroxymethyl) aminomethane buffer solution (Tris-HCl)) is added, and the mixture is stirred at room temperature for 72h, filtered by suction and dried. And (3) placing the obtained sample in a tube furnace, and calcining at a high temperature of 500 ℃ for 3 hours in an inert atmosphere to obtain a binary topology structure of 0D phosphorus/3D carbon, wherein carbon formed by pyrolysis is coated on the surface of phosphorus in the composite material as shown in figure 1. Mixing 0.5g of 0D phosphorus/3D carbon with 0.02g of lithium foil, then heating in an iron crucible at 300 ℃ for 1h in a glove box, naturally cooling and fully grinding, and heating at 300 ℃ for 1h to obtain the binary topological structure of the prelithiated 0D phosphorus/3D carbon.

The composite material obtained in this example was used as an active material, and was pressed onto a foam nickel substrate having a diameter of 12mm at a weight ratio of 80:10:10 with conductive carbon black (SP) and polyvinylidene fluoride (PVDF) as an adhesive. The assembled battery is a CR2032 button battery by taking metal lithium as a negative electrode and taking a Cegard2300 microporous polypropylene film with the diameter of 16mm as a diaphragm.

And (3) cyclic test: when the blue-ray testing system is used for testing, the temperature is room temperature, constant-current charging and discharging are adopted, the voltage control range is 0.01-3V, and the constant-current charging and discharging are carried out at the current density of 100 mA/g.

Wherein the specific charge (discharge) capacity=charge (discharge) capacity/active material mass, and the above capacity test process is circulated to obtain the n-time capacity retention rate=n-th discharge specific capacity/first discharge specific capacity.

High-rate test: when the blue-ray testing system is used for testing, the temperature is room temperature, constant-current charging and discharging are adopted, the voltage control range is 0.01-3V, and constant-current charging and discharging are carried out at the current density of 1000 mA/g.

Example 2:

1g of red phosphorus is taken in a 250mL four-necked flask, 150mL of 2mg/mL dopamine solution (the solvent is Tris (hydroxymethyl) aminomethane buffer solution (Tris-HCl)) is added, and the mixture is stirred for 72h, filtered by suction and dried. And (3) placing the obtained sample in a tube furnace, and calcining at 600 ℃ for 3 hours under an inert atmosphere to obtain the binary topology structure of 0D phosphorus/3D carbon. Mixing 0.5g of 0D phosphorus/3D carbon with 0.02g of lithium foil, placing in an iron crucible, heating for 1h at 300 ℃ in a glove box, naturally cooling, fully grinding, and heating for 1h at 300 ℃ to obtain the binary topological structure of the prelithiated 0D phosphorus/3D carbon.

The composite prepared in this example was used as an active material, and the battery was assembled by the raw materials and the assembly process in reference example 1, and the initial discharge specific capacity was reduced, and the rate performance, the cycle stability and the reversible capacity were all improved. It is assumed that the reason for this is that as the temperature increases, phosphorus evaporated from the carbon core increases, phosphorus in the composite decreases, and the specific capacity decreases. And as the temperature increases, the graphitization degree of the carbon material increases, which is beneficial to the improvement of the conductivity of the material.

Example 3:

mixing 0.9g of black phosphorus and 0.3g of carbon nano tube through ball milling, placing the mixture in an iron crucible, adding 0.6g of lithium foil, heating the mixture in a glove box at 300 ℃ for 1.5h, and heating the mixture at 500 ℃ for 1h after natural cooling and full grinding to obtain the prelithiated 0D phosphorus/1D carbon binary topological structure.

FIG. 2 is an XRD pattern of the binary topology of the prelithiated 0D phosphorus/1D carbon, after prelithiation, the phosphorus in the composite material is converted to lithium phosphide Li _x P (x=1, 3). FIG. 3 is an SEM image of the binary topology of the prelithiated 0D phosphorus/1D carbon, from which it can be seen that the lithiated composite material still exhibits a 0D/1D binary topologyThe surface of the carbon nanotubes becomes roughened, possibly due to the formation of lithium phosphide particles on the surface of the carbon nanotubes.

The composite prepared in the embodiment is used as an active substance, the battery is assembled by the raw materials and the assembly process in the reference embodiment 1, the first-week discharge specific capacity can reach 1847.8 under the current density of 100mA/g, the first-week coulomb efficiency can reach 87.2%, and the discharge specific capacity can still reach 667.3mAh/g after 1000 weeks of circulation when the current density reaches 1000 mA/g.

Example 4

And respectively placing 1g of red phosphorus and 1g of expanded graphite in two heating temperature areas of a tubular furnace chamber, heating the red phosphorus at the temperature of 450 ℃, and reacting for 4 hours at the temperature of 300 ℃ in the temperature area of the expanded graphite to obtain a binary topology structure of 0D phosphorus/2D carbon. Mixing 0.5g of 0D phosphorus/2D carbon with 0.02g of lithium foil, heating in a glove box at 300 ℃ for 1h, naturally cooling, fully grinding, and heating at 300 ℃ for 1h to obtain a prelithiated 0D phosphorus/2D carbon binary topological structure (figure 4).

The battery was assembled with the composite prepared in this example as an active material in the raw material and assembly process of reference example 1, and its rate capability was greatly improved. It is presumed that the reason for this is that the abundant functional groups between the expanded graphite layers act with P to form a stable chemical force.

Example 5:

mixing 0.5g of expanded graphite with 0.02g of lithium foil, placing the mixture in an iron crucible, calcining the mixture at 300 ℃ for 2 hours in a glove box to obtain lithiated expanded graphite, adding 0.5g of red phosphorus, mixing the mixture, and heating the mixture at 300 ℃ for 2 hours to obtain a prelithiated 0D phosphorus/2D carbon binary topology structure.

The compound prepared in the embodiment is used as an active substance, the battery is assembled by the raw materials and the assembly process in reference embodiment 1, the specific capacity of the battery can reach 1698.6mAh/g at the first week, the capacity retention rate can reach 84.7% after 100 weeks of circulation, and the specific capacity of the battery can still reach 512.4mAh/g after 1000 weeks of circulation under the current density of 1000 mA/g.

Example 6:

mixing 0.5g of red phosphorus with 0.02g of lithium foil, placing the mixture in an iron crucible, calcining the mixture in a glove box at 300 ℃ for 2 hours and then at 450 ℃ for 2 hours to obtain a lithium phosphide material, adding 0.5g of expanded graphite, mixing the mixture, and heating the mixture at 300 ℃ for 3 hours to obtain the prelithiated 0D phosphorus/2D carbon binary topology structure.

The battery was assembled by using the composite prepared in this example as an active material in the raw material and assembly process of reference example 1, and its specific capacity, rate performance and cycle stability were all lowered as compared with example 4.

Example 7

1.0gP was taken ₂ O ₅ Adding 120mL of hydrochloric acid with the molar concentration of 0.1mol/L into a four-necked flask, dropwise adding 480 mu L of aniline, stirring for 0.5h, dropwise adding 80mL of ammonium persulfate with the mass fraction of 1%, and stirring for 24h in an ice water bath at the rotating speed of 600rpm to obtain polyaniline-coated P ₂ O ₅ And (3) placing the composite material in a tube furnace, and calcining at 400 ℃ for 3 hours to obtain the composite material. Taking 0.5g of the carbon-coated phosphorus porous composite material, putting the composite material into an iron crucible, adding 0.05g of lithium foil, heating the composite material for 1.5h at 300 ℃ in a glove box, and heating the composite material for 1h at 400 ℃ after the composite material is naturally cooled and fully ground to obtain a prelithiated 0D phosphorus/3D carbon binary topological structure (figure 5).

The composite prepared in the embodiment is used as an active substance, the battery is assembled by the raw materials and the assembly process in reference embodiment 1, the first-week discharge specific capacity can reach 1804.3 under the current density of 100mA/g, the first-week coulomb efficiency can reach 86.1%, when the current density reaches 1000mA/g, the first-week discharge specific capacity can reach 782.6mAh/g, and after 1000 weeks of circulation, the discharge specific capacity can still reach 645.2mAh/g.

Comparative example 1

The binary topology preparation method of 0D phosphorus/3D carbon is the same as example 1, except that the lithiation step is added in example 1, while the lithiation step is not added in comparative example 1. The first discharge specific capacity of comparative example 1 at a current density of 100mA/g can reach 1912.5mAh/g, but the first week coulomb efficiency is only 52.4%, and when the current density is 1000mA/g, the discharge specific capacity of 289.8mAh/g can only be maintained after 1000 weeks of circulation.

Comparative example 2

The binary topology preparation method of 0D phosphorus/2D carbon is the same as example 4, except that example 4 adds a lithiation step, whereas comparative example 2 does not. The initial cycle specific capacity obtained in comparative example 2 was 1816.8mAh/g at a current density of 100mA/g in charge and discharge, the initial cycle coulomb efficiency was 61.2%, the capacity retention rate was 50.3% after 100 cycles, and the discharge specific capacity was 312.5mAh/g after 1000 cycles at a current density of 1000 mA/g.

Table 1 electrochemical performance of each lithium battery in examples

As can be seen from Table 1, when the composite material prepared by the method of the invention is an active material, the first coulombic efficiency and the high-rate charge-discharge performance of the phosphorus-based anode material can be obviously improved.

The present invention has been described in detail with reference to the embodiments and the accompanying drawings, which are only for aiding in the understanding of the method and core idea of the present invention; also, it is intended that all such modifications within the scope of the invention be included as would be within the scope of the invention, as would be apparent to those skilled in the art in light of the spirit and principles of the present invention.

Claims

1. A pre-lithiated binary topological structure phosphorus/carbon composite material is lithiated x-dimensional phosphorus/y-dimensional carbon, wherein x and y are integers, x is more than or equal to 0 and less than or equal to 3, and y is more than or equal to 1 and less than or equal to 3;

the pre-lithiated binary topological structure phosphorus/carbon composite material is prepared by the following steps:

(a) Coating a phosphorus source by using a coating material, and then carbonizing at high temperature to obtain x-dimensional phosphorus/y-dimensional carbon with a binary topological structure, wherein x and y are integers, x is more than or equal to 0 and less than or equal to 3, and y is more than or equal to 1 and less than or equal to 3;

the mass ratio of the phosphorus source to the coating material is 3:1-30:1, and the coating material is an organic amine compound;

(b) Mixing the binary topological structure x-dimensional phosphorus/y-dimensional carbon obtained in the step (a) with a lithium source for lithiation; wherein the lithiation temperature is 180-400 ℃.

2. The prelithiated binary topology phosphorus/carbon composite of claim 1, wherein the phosphorus is amorphous red phosphorus, violet phosphorus, fibrous phosphorus, black phosphorus or blue phosphorus.

3. The prelithiated binary topology phosphorus/carbon composite of claim 1, wherein the carbon is a one-dimensional tubular carbon-based material, a two-dimensional layered carbon-based material, or a three-dimensional porous carbon material.

4. A method of preparing the prelithiated binary topology phosphorus/carbon composite of any of claims 1-3, comprising the steps of:

the mass ratio of the phosphorus source to the coating material is 3:1-30:1; the coating material is an organic amine compound;

(b) Carrying out lithiation treatment on the binary topological structure x-dimensional phosphorus/y-dimensional carbon obtained in the step (a) by using a lithium source; wherein the lithiation temperature is 180-400 ℃.

5. The method according to claim 4, wherein the coating material is dopamine.

6. The process according to claim 4, wherein the phosphorus source is elemental phosphorus or a compound which forms stable elemental phosphorus after pyrolysis.

7. The process according to claim 5, wherein the phosphorus source is elemental phosphorus or a compound which forms stable elemental phosphorus after pyrolysis.

8. The process according to claim 4, wherein the phosphorus source is a phosphorus-oxygen compound.

9. The process according to claim 5, wherein the phosphorus source is a phosphorus-oxygen compound.

10. The production method according to claim 8, wherein the phosphorus oxide compound is phosphorus pentoxide.

11. The production method according to claim 9, wherein the phosphorus oxide compound is phosphorus pentoxide.

12. The production method according to any one of claims 4 to 11, wherein the carbonization temperature is 300 to 1000 ℃.

13. The method of claim 12, wherein the carbonization temperature is 350-800 ℃.

14. The method of claim 13, wherein the carbonization temperature is 500-700 ℃.

15. The production method according to any one of claims 4 to 11, wherein the elemental mass ratio of lithium source to phosphorus source is 1:1 to 1:200.

16. The production method according to claim 12, wherein the mass ratio of the lithium source to the phosphorus source is 1:1 to 1:200.

17. The preparation method according to any one of claims 4 to 11, wherein the lithium source is a lithium foil, lithium powder, molten lithium, inorganic lithium salt or Li-organic complex solution.

18. The method of claim 12, wherein the lithium source is a lithium foil, lithium powder, molten lithium, inorganic lithium salt, or Li-organic complex solution.

19. The method of claim 15, wherein the lithium source is a lithium foil, lithium powder, molten lithium, inorganic lithium salt, or Li-organic complex solution.

20. A negative electrode of a lithium ion battery, wherein an active substance is the pre-lithiated binary topological structure phosphorus/carbon composite material according to any one of claims 1-3 or the pre-lithiated binary topological structure phosphorus/carbon composite material prepared by the method according to any one of claims 4-19.

21. A lithium ion battery comprising the lithium ion battery anode of claim 20.