CN-120864481-B - Preparation method of composite high-entropy hard carbon negative electrode material and sodium ion battery

CN120864481BCN 120864481 BCN120864481 BCN 120864481BCN-120864481-B

Abstract

The invention discloses a preparation method of a composite high-entropy hard carbon negative electrode material and a sodium ion battery, and relates to the technical field of electrochemical energy storage materials. The invention breaks through the existing doping limit through the high-entropy design, realizes five-membered and above atomic-level mixing, has strong structural stability which cannot be realized by the traditional binary/ternary doping, utilizes the preassembly technology to combine with step carbonization, completes molecular anchoring and entropy locking, overcomes the pain point problem of multi-element segregation, synchronously improves the sodium storage dynamics and thermodynamic performance of a high-entropy hard carbon precursor and an intermediate through the careful combination design of multiple elements and the optimization of the subsequent carbonization process parameters, realizes triple regulation and control of defect-interlayer spacing-pore structure, reduces the defect degree of the high-entropy hard carbon through the design of a coating process, and the prepared composite high-entropy hard carbon negative electrode material shows excellent comprehensive performance in sodium ion batteries, and particularly has obvious advantages in high first coulomb efficiency, high multiplying power capability and long stability.

Inventors

LI CHUANG
XU LIZHI
CHEN JUNXIONG
WANG YONGSHENG

Assignees

合肥国科碳芯科技有限公司

Dates

Publication Date: 20260505
Application Date: 20250805

Claims (3)

1. The preparation method of the composite high-entropy hard carbon anode material is characterized by comprising the following steps of: s1, placing 0.1g of urea, 0.1g of sulfur powder, 0.1g of cobalt nitrate, 0.1g of ammonium molybdate, 0.1g of manganese acetate and 10g of carbon source bamboo powder into a high-energy ball mill for mixing for 5 hours, wherein the ball milling speed is 1000rpm, so as to obtain high-entropy precursor powder; s2, under Ar atmosphere, heating to 300 ℃ at a rate of 2 ℃ per minute, and performing first carbonization treatment on the high-entropy precursor for 3 hours to obtain a high-entropy hard carbon intermediate; and S3, under the Ar atmosphere, heating to 1300 ℃ at a rate of 5 ℃ per minute, and performing second carbonization treatment on the high-entropy hard carbon intermediate for 3 hours to obtain the high-entropy hard carbon material: S4, soaking the high-entropy hard carbon material in an acid solution with the mass fraction of V Hydrochloric acid :V Hydrofluoric acid = 1:1 of 10%, heating to 50 ℃ on a magnetic stirrer, stirring and soaking for 12 hours at 300r/min, carrying out suction filtration and washing by using deionized water until the filtrate is neutral, and finally drying for 12 hours in a vacuum oven with the conductivity of less than 20 mu S/cm at 110 ℃ to obtain the deashed high-entropy hard carbon material; S5, adding a deashing high-entropy hard carbon material and 3wt% of a coating agent phenolic resin into a ball milling tank, and ball milling for 2 hours at a rotating speed of 1000rpm under the condition of room temperature to obtain the high-entropy hard carbon material with a phenolic resin coating structure; And then heating to 1300 ℃ at a rate of 5 ℃ per minute under Ar atmosphere, and performing third carbonization treatment for 3 hours to obtain the composite high-entropy hard carbon anode material.
2. The method for preparing the composite high-entropy hard carbon anode material according to claim 1, which is characterized by comprising the following steps of S1, placing 0.1g of urea, 0.1g of sulfur powder, 0.1g of cobalt nitrate, 0.1g of ammonium molybdate, 0.1g of manganese acetate and 10g of carbon source bamboo powder into a high-energy ball mill for mixing for 5 hours, wherein the ball milling speed is 1000rpm, so as to obtain high-entropy precursor powder; s2, under Ar atmosphere, heating to 300 ℃ at a rate of 2 ℃ per minute, and performing first carbonization treatment on the high-entropy precursor for 3 hours to obtain a high-entropy hard carbon intermediate; s3, adding 0.1g of aluminum chloride, 0.1g of chromium sulfate and 0.1g of antimony chloride serving as auxiliary doping sources into the high-entropy hard carbon intermediate, heating to 1300 ℃ at a rate of 5 ℃ per minute under the Ar atmosphere, and performing second carbonization treatment on the high-entropy hard carbon intermediate for 3 hours to obtain the high-entropy hard carbon material: S4, soaking the high-entropy hard carbon material in an acid solution with the mass fraction of V Hydrochloric acid :V Hydrofluoric acid = 1:1 of 10%, heating to 50 ℃ on a magnetic stirrer, stirring and soaking for 12 hours at 300r/min, carrying out suction filtration and washing by using deionized water until the filtrate is neutral, and finally drying for 12 hours in a vacuum oven with the conductivity of less than 20 mu S/cm at 110 ℃ to obtain the deashed high-entropy hard carbon material; S5, adding a deashing high-entropy hard carbon material and 3wt% of a coating agent phenolic resin into a ball milling tank, and ball milling for 2 hours at a rotating speed of 1000rpm under the condition of room temperature to obtain the high-entropy hard carbon material with a phenolic resin coating structure; And then heating to 1300 ℃ at a rate of 5 ℃ per minute under Ar atmosphere, and performing third carbonization treatment for 3 hours to obtain the composite high-entropy hard carbon anode material.
3. A sodium ion battery, characterized by comprising the composite high-entropy hard carbon anode material prepared by the preparation method of any one of claims 1-2.

Description

Preparation method of composite high-entropy hard carbon negative electrode material and sodium ion battery Technical Field The invention relates to the technical field of electrochemical energy storage materials, in particular to a preparation method of a composite high-entropy hard carbon negative electrode material and a sodium ion battery. Background In recent years, lithium resources which are limited in resources, unevenly distributed and expensive cannot meet the increasing energy consumption of people in production and life. Sodium ion batteries have great development potential in the field of large-scale energy storage due to the advantages of abundant sodium resources, low cost, high safety and the like. However, developing high performance, long life, low cost anode materials is a key challenge to achieving commercialization of sodium ion batteries. Sodium ions are difficult to intercalate into the graphite layers due to the restriction of the small interlayer spacing of the graphite, and have poor electrochemical properties. The hard carbon material is considered as the sodium ion battery cathode material with the most prospect at present because of rich sodium storage sites, low working potential and adjustable structure. However, the traditional hard carbon material still has the problems of low Initial Coulombic Efficiency (ICE), low rate capability to be improved, insufficient long-cycle stability and the like, and restricts the large-scale application of the sodium ion battery. The concept of 'high entropy' is widely applied in the field of material science and shows excellent performance regulation and control capability. The high-entropy material is generally composed of five or more principal elements in a nearly equal atomic ratio, has the characteristics of high configuration entropy, lattice distortion, slow diffusion, cocktail effect and the like, and can remarkably improve the mechanical property, thermal stability, chemical stability and electrochemical property of the hard carbon material. The doped metal elements (such as Co, mg, ni, sn and the like) not only improve the conductivity of the hard carbon material, but also can catalyze and regulate the growth of graphite-like microcrystals, thereby realizing the reintegration of the carbon layer structure and the optimization of the pore structure. The introduction of nonmetallic elements (such as N, P, S and the like) can enlarge the carbon layer spacing to enhance the diffusion kinetics of sodium ions, adjust the pore structure and the defect proportion to create more sodium storage adsorption sites, and finally realize the improvement of electrochemical performance. However, how to use an effective strategy to achieve the introduction of nonmetallic elements and metallic elements to prepare a high-magnification, high-capacity, high-entropy hard carbon material with optimized graphite-like crystallites and amorphous component ratios, reasonable defect sites, and abundant closed cell structures remains a pain spot problem faced at present. Disclosure of Invention The invention aims to provide a preparation method of a composite high-entropy hard carbon negative electrode material, which aims to solve the problems of low initial coulombic efficiency, poor multiplying power performance and poor cycle stability of the hard carbon negative electrode material; The second purpose of the invention is to provide a sodium ion battery, which comprises the prepared composite high-entropy hard carbon anode material. The aim of the invention can be achieved by the following technical scheme: in a first aspect, a method for preparing a composite high-entropy hard carbon anode material includes the following steps: s1, mixing a mixed element doping source with a carbon source, and performing pretreatment to obtain a high-entropy precursor; s2, performing first carbonization treatment on the high-entropy precursor in an inert atmosphere to obtain a high-entropy hard carbon intermediate; s3, carrying out second carbonization treatment on the high-entropy hard carbon intermediate in an inert atmosphere to obtain a high-entropy hard carbon material: s4, carrying out acid washing and deashing treatment on the high-entropy hard carbon material, and carrying out vacuum drying to obtain a deashed high-entropy hard carbon material; And S5, adding a coating agent into the deashing high-entropy hard carbon material, coating, and performing third carbonization treatment in an inert atmosphere to obtain the composite high-entropy hard carbon negative electrode material. In the step S1, the carbon source is any one of bamboo powder, coconut shell, sugarcane, poplar, cotton, wheat, corn stalk, reed, distillers grains, seaweed, oak, palm shell, walnut shell, starch and resin. Further, bamboo powder, coconut shells, sugarcane, poplar, cotton, wheat, corn stalks, reed, distillers grains, seaweed, oak, palm shells, walnut shells or starch are crushed by a crusher