CN-122000342-A - Lithium/sodium ion battery phosphorus-carbon negative electrode material and preparation method thereof

CN122000342ACN 122000342 ACN122000342 ACN 122000342ACN-122000342-A

Abstract

The invention provides a phosphorus-carbon negative electrode material of a lithium/sodium ion battery and a preparation method thereof, wherein the phosphorus-carbon negative electrode material of the lithium/sodium ion battery takes porous carbon as a matrix, red phosphorus is deposited in the porous carbon, iodine simple substances are doped in the porous carbon, and a layer of titanium dioxide is coated on the surface of the phosphorus-carbon negative electrode material to form a C/P-I@TiO 2 composite material with a core-shell structure. The method can inhibit the volume expansion of the red phosphorus, reduce the contact area of the electrolyte and the red phosphorus, and improve the cycle performance, the coulomb efficiency and the multiplying power performance of the lithium/sodium ion battery.

Inventors

YUE ZHIHAO
LI YINGQIAN
XIONG JIAHAO
JIN CHENXIN
WEN LIJUN
Ma Haoqiang

Assignees

南昌大学

Dates

Publication Date: 20260508
Application Date: 20260409

Claims (10)

1. The phosphorus-carbon negative electrode material of the lithium/sodium ion battery is characterized in that porous carbon is used as a matrix, red phosphorus is deposited in the porous carbon, iodine simple substances are doped in the porous carbon, and a layer of titanium dioxide is coated on the surface of the phosphorus-carbon negative electrode material to form a C/P-I@TiO 2 composite material with a core-shell structure.
2. The phosphorus-carbon negative electrode material of the lithium/sodium ion battery, as claimed in claim 1, wherein the thickness of the titanium dioxide coating layer is 5-15 nm.
3. The lithium/sodium ion battery phosphorus-carbon anode material of claim 1, wherein the porous carbon has an internally deposited phosphorus content of 35-45wt%.
4. The phosphorus-carbon negative electrode material of a lithium/sodium ion battery according to claim 1, wherein the particle size of the porous carbon raw material is 5-6um, and the pore size of the porous carbon is 1-3nm.
5. The preparation method of the phosphorus-carbon negative electrode material of the lithium/sodium ion battery is characterized by comprising the following steps of: A. The particle size of the porous carbon is reduced by controlling a certain ball-material ratio, rotating speed and ball milling time; B. C, placing the porous carbon matrix obtained in the step A at the cold end of the tube furnace, placing the raw material red phosphorus at the hot end of the tube furnace, drying, cooling, and adding the iodine simple substance into the cold end of the tube furnace; C. B, vacuumizing the tubular furnace, heating the hot end of the tubular furnace for the first step to thermally decompose red phosphorus to generate white phosphorus steam, constructing a temperature gradient at the porous carbon crucible at the cold end, and making the porous carbon crucible at the cold end lower than the ambient temperature of the crucible so that the white phosphorus steam is preferentially collected at the porous carbon crucible with lower temperature and continuously and uniformly deposited in the porous carbon pores at the cold end; D. C, moving the tubular furnace in the step C to enable the porous carbon at the cold end to enter the hot end, then introducing protective gas until the air pressure reaches positive pressure, and then heating in the second step to enable white phosphorus in the porous carbon to be converted into red phosphorus under the catalysis of iodine, cooling and screening to obtain the C/P-I composite material; E. Mixing the C/P-I composite material obtained in the step D, tetrabutyl titanate and absolute ethyl alcohol serving as a solvent according to a certain proportion, stirring, and carrying out spray drying on the uniformly mixed solution to obtain a precursor of the C/P-I@TiO 2 composite material; F. C/P-I@TiO 2 composite material precursor obtained in the step E is placed into a water bath kettle to be heated in a water bath, so that tetrabutyl titanate is hydrolyzed to generate titanium hydroxide, and the titanium hydroxide is coated on the surface of the C/P-I composite material; G. And F, adding the C/P-I composite material powder coated with the titanium hydroxide obtained in the step F into a tubular furnace, introducing protective gas, and performing heat treatment to decompose a titanium hydroxide coating layer on the surface of the C/P-I composite material to obtain a final product C/P-I@TiO 2 composite material.
6. The method for preparing a phosphorus-carbon negative electrode material of a lithium/sodium ion battery according to claim 5, wherein in the step B, the ratio of the raw material red phosphorus to the porous carbon to the elemental iodine is 45-55:15-25:2-5.
7. The method for preparing the phosphorus-carbon negative electrode material of the lithium/sodium ion battery according to claim 5, wherein in the step C, the vacuum degree is-0.05 MPa to-0.1 MPa, the first-step heating temperature is 400-700 ℃, the first-step heating rate is 4-10 ℃ per minute, and the first-step heating and heat preservation time is 5-8 hours.
8. The method for preparing a phosphorus-carbon negative electrode material of a lithium/sodium ion battery according to claim 5, wherein in the step C, the temperature gradient is constructed so that the temperature at the cold end of the porous carbon crucible is lower than the ambient temperature of the crucible by 50-100 ℃.
9. The method for preparing a phosphorus-carbon negative electrode material of a lithium/sodium ion battery according to claim 5, wherein in the step D, the positive pressure is 0-0.1 MPa, the second-step heating temperature is 150-300 ℃, and the second-step heating and heat preservation time is 12-24 h.
10. The method for preparing a phosphorus-carbon negative electrode material of a lithium/sodium ion battery according to claim 5, wherein in the step E, the ratio of the raw material C/P-I composite material to the anhydrous ethanol to the tetrabutyl titanate is 1-3:30-40:1-2, and the stirring time is 1-3 h.

Description

Lithium/sodium ion battery phosphorus-carbon negative electrode material and preparation method thereof Technical Field The invention relates to the field of new energy lithium/sodium ion batteries, in particular to a phosphorus-carbon negative electrode material of a lithium/sodium ion battery and a preparation method thereof. Background In recent years, with the continuous increase of the demand of advanced energy storage materials, phosphorus has become one of the electrode materials with great application prospects in the field of lithium/sodium ion batteries. The red phosphorus has high theoretical specific capacity (2596 mAh g -1) and lower lithium intercalation/sodium intercalation potential (0.4V/0.3V), and can effectively avoid the formation of metal dendrites. However, during lithiation/sodium treatment, red phosphorus undergoes a large volume expansion (up to 300%) resulting in pulverization of the active material. Therefore, how to inhibit the volume expansion of red phosphorus and reduce the contact area of electrolyte and red phosphorus so as to improve the cycle performance, coulombic efficiency and rate capability of the lithium/sodium ion battery is a technical problem to be solved at present. Disclosure of Invention Therefore, the invention provides the lithium/sodium ion battery phosphorus-carbon negative electrode material which can inhibit the volume expansion of red phosphorus, reduce the contact area of electrolyte and red phosphorus and improve the cycle performance, coulombic efficiency and multiplying power performance of the lithium/sodium ion battery, the preparation method thereof and the lithium/sodium ion battery phosphorus-carbon negative electrode. The phosphorus-carbon negative electrode material of the lithium/sodium ion battery takes porous carbon as a matrix, red phosphorus is deposited in the porous carbon, iodine simple substance is doped in the porous carbon, and a layer of titanium dioxide is coated on the surface of the phosphorus-carbon negative electrode material, so that the C/P-I@TiO 2 composite material with a core-shell structure is formed. The porous carbon pores of the phosphorus-carbon cathode material of the lithium/sodium ion battery contain red phosphorus, so that the gram capacity of the sodium ion battery can be effectively improved, the titanium dioxide coating layer can inhibit the volume expansion of the red phosphorus, the contact area between electrolyte and the red phosphorus can be reduced, the cycle performance, coulomb efficiency and multiplying power performance of the lithium/sodium ion battery can be improved, air can be isolated, oxidation of the red phosphorus in the pores can be avoided, and a large amount of SEI films generated by contact of the red phosphorus material and the electrolyte can be avoided, so that the capacity of the lithium/sodium ion battery can be rapidly reduced. Further, the thickness of the titanium dioxide coating layer is 5-15 nm. Further, the porous carbon has a content of internally deposited phosphorus of 35 to 45wt%. Further, the particle size of the porous carbon raw material is 5-6um, and the pore size of the porous carbon is 1-3nm. The invention also provides a preparation method of the phosphorus-carbon negative electrode material of the lithium/sodium ion battery, which comprises the following steps: A. The particle size of the porous carbon is reduced by controlling a certain ball-material ratio, rotating speed and ball milling time; B. C, placing the porous carbon matrix obtained in the step A at the cold end of the tube furnace, placing the raw material red phosphorus at the hot end of the tube furnace, drying, cooling, and adding the iodine simple substance into the cold end of the tube furnace; C. Vacuumizing the tubular furnace in the step B, then heating the hot end of the tubular furnace in the first step to thermally decompose red phosphorus to generate white phosphorus vapor, constructing a temperature gradient at the porous carbon crucible at the cold end, and making the porous carbon crucible at the cold end lower than the ambient temperature of the crucible so that the white phosphorus vapor is preferentially collected at the porous carbon crucible at the lower temperature and continuously and uniformly deposited in the porous carbon pores at the cold end; D. C, moving the tubular furnace in the step C to enable the porous carbon at the cold end to enter the hot end, then introducing protective gas until the air pressure reaches positive pressure, and then heating in the second step to enable white phosphorus in the porous carbon to be converted into red phosphorus under the catalysis of iodine, cooling and screening to obtain the C/P-I composite material; E. Mixing the C/P-I composite material obtained in the step D, tetrabutyl titanate and absolute ethyl alcohol serving as a solvent according to a certain proportion, stirring, and carrying out spray drying on the uniformly mixed solution to