阅读说明：本技术 片状碳基质内部均匀桥接超细MoO2纳米颗粒的电极材料及其制备方法和应用 (Superfine MoO uniformly bridged inside flaky carbon matrix2Electrode material of nano particles and preparation method and application thereof ) 是由 麦立强 余若瀚 陈子昂 周亮 于 2020-07-17 设计创作，主要内容包括：本发明涉及纳米材料与电化学技术领域,特别是涉及一种片状碳基质内部均匀桥接超细MoO<Sub>2</Sub>纳米颗粒的电极材料及其制备方法,该材料可作为高容量、长循环寿命锂离子电池负极活性材料,其为片状碳基质亚结构层叠交织组成的三维花状结构,其中,碳基质的片层厚度为10-20nm,所述的碳基质组成的单个花状结构的直径为2-6um,所述的MoO<Sub>2</Sub>纳米颗粒直径为1-3nm。该纳米材料可作为锂离子电池负极材料。本发明材料具有工艺简单、反应条件温和、材料电化学性能优异的特点。(The invention relates to the technical field of nano materials and electrochemistry, in particular to a flaky carbon matrix internally and uniformly bridged superfine MoO 2 Electrode material of nano particles and preparation method thereof, and nano particlesThe material can be used as a negative active material of a lithium ion battery with high capacity and long cycle life, and is a three-dimensional flower-shaped structure formed by laminating and interweaving sheet-shaped carbon matrix substructures, wherein the thickness of a sheet layer of the carbon matrix is 10-20nm, the diameter of a single flower-shaped structure formed by the carbon matrix is 2-6um, and the MoO is 2 The diameter of the nano-particles is 1-3 nm. The nano material can be used as a lithium ion battery cathode material. The material has the characteristics of simple process, mild reaction conditions and excellent electrochemical performance.)

1. Superfine MoO uniformly bridged inside flaky carbon matrix₂The electrode material of the nano particles is a three-dimensional flower-shaped structure formed by laminating and interweaving sheet-shaped carbon matrix substructures, wherein the thickness of a sheet layer of the carbon matrix is 10-20nm, the diameter of a single flower-shaped structure formed by the carbon matrix is 2-6um, and the MoO is₂The diameter of the nano-particles is 1-3 nm.

2. The flaky carbon substrate of claim 1 in which ultrafine MoO is uniformly bridged inside₂The preparation method of the electrode material of the nano particles comprises the following steps: adding MoO₃Adding the nanobelt solution and dopamine hydrochloride into a deionized water solution of trihydroxymethyl aminomethane, fully and uniformly stirring at room temperature, washing, and drying to obtain a flower-shaped Mo-polydopamine composite material; sintering the obtained product in an inert atmosphere to obtain the superfine MoO uniformly bridged in the flaky carbon matrix₂Electrode material of nanoparticles.

3. The carbon substrate of claim 2, wherein the ultrafine MoO is uniformly bridged inside the sheet-like carbon substrate₂A method for preparing a nanoparticle electrode material, characterized in that said MoO₃The preparation method of the nanobelt solution comprises the following steps:

1) mixing Mo powder with H₂O₂And H₂Stirring the mixture in the O mixed solution uniformly;

2) transferring the solution obtained in the step 1) into a reaction container for heating, taking out, and naturally cooling to room temperature to obtain MoO₃Nanobelt solution.

4. The carbon substrate of claim 2, wherein the ultrafine MoO is uniformly bridged inside the sheet-like carbon substrate₂A method for preparing electrode material of nano particles is characterized in thatThe time for fully stirring is 2-8 h.

5. The flaky carbon substrate of claim 3 in which ultrafine MoO is uniformly bridged inside₂The preparation method of the electrode material of the nano particles is characterized in that the mass of the Mo powder in the step 1) is 0.5-3.5 g; h in the mixed solution₂O₂And H₂O two are 10-80mL each.

6. The carbon substrate of claim 2, wherein the ultrafine MoO is uniformly bridged inside the sheet-like carbon substrate₂A method for preparing a nanoparticle electrode material, characterized in that said MoO₃The nano-belt solution is 1-10mL, the dopamine hydrochloride is 0.1-1g, the tris (hydroxymethyl) aminomethane is 0.1-1g, and the deionized water is 20-200 mL.

7. The sheet-like carbon matrix of claim 3, wherein the inside of the matrix is uniformly bridged with ultrafine MoO₂The preparation method of the electrode material of the nano-particles is characterized in that the heating temperature is 160-200 ℃, and the heating time is 6-48 h.

8. The carbon substrate of claim 2, wherein the ultrafine MoO is uniformly bridged inside the sheet-like carbon substrate₂The preparation method of the electrode material of the nano-particles is characterized in that the sintering temperature is 600-1000 ℃, and the sintering time is 1-4 h.

9. The flaky carbon substrate of claim 1 in which ultrafine MoO is uniformly bridged inside₂The nano-particle electrode material is applied as a negative electrode active material of a lithium ion battery with high capacity and long cycle life.

Technical Field

The invention relates to the technical field of nano materials and electrochemistry, in particular to a flaky carbon matrix internally and uniformly bridged superfine MoO₂The material can be used as a negative electrode active material of a lithium ion battery with high capacity and long cycle life.

Background

Energy shortage and environmental pollution have become two major problems facing the world today. The development and utilization of green clean energy has great significance for relieving energy shortage and reducing environmental pollution. At present, a lithium ion battery is taken as one of representatives of clean energy storage systems, and is widely applied to the fields of portable electronic equipment, automobile power batteries, large-scale energy storage and the like. However, the current commercialized graphite anode has low specific capacity (372mAh g)^-1) And the safety is poor, and the increasing energy density requirement is difficult to meet. And with the further expansion of energy demand, the shortage of lithium resources will severely restrict the application and development thereof, which also puts higher demands on the full utilization of the existing lithium resources: the capacity and the cycle life of the electrode material are further improved under the existing conditions. Transition Metal Oxides (TMOs) based on a conversion reaction mechanism are lithium battery cathode materials with great development prospects. Over the past decades, a large number of transition metal oxides, such as Fe, have been extensively studied₂O₃、V₂O₅、MoO₃And the like.

Due to low metal resistivity (8.8 × 10)^-5Ω·cm^-1) High theoretical capacity (838mAh g)^-1) And low cost, molybdenum dioxide (MoO)₂) Has been considered one of the most attractive anode materials. However, two key problems with this electrode material are that during charging and discharging, the MoO is present₂The intermediates of nanoparticle conversion reactions often suffer from poor lithium intercalation kinetics and severe volume expansion, resulting in undesirable cycle performance and lifetime. In recent years, smaller volume expansion and fast dissociation of composite carbon matrices by constructing elaborate nanostructures has been achievedThe improvement of the electrochemical performance by the electron/electron transmission speed becomes a research hotspot, and the uniform carbon composite structure is constructed on the ultra-small nanometer scale (less than 5nm) to form the ultra-fine MoO₂The electrode material with nano particles uniformly bridged inside the flaky carbon matrix, high capacity and cycle life of more than 1000 circles is not reported.

Disclosure of Invention

In view of the above, the present invention provides a method for uniformly bridging ultrafine MoO inside a flaky carbon matrix₂The electrode material of the nano particles, the preparation method and the application thereof have the characteristics of high capacity and stable circulation, and the energy density of the lithium ion battery cathode material is greatly improved, and the excellent stability is also shown.

The technical scheme adopted by the invention for solving the problems is as follows: superfine MoO uniformly bridged inside flaky carbon matrix₂The electrode material of the nano particles is a three-dimensional flower-shaped structure formed by laminating and interweaving sheet-shaped carbon matrix substructures, wherein the thickness of a sheet layer of the carbon matrix is 10-20nm, the diameter of a single flower-shaped structure formed by the carbon matrix is 2-6um, and the MoO is₂The diameter of the nano-particles is 1-3 nm.

The inside of the flaky carbon matrix is uniformly bridged with ultrafine MoO₂The preparation method of the electrode material of the nano particles comprises the following steps: adding MoO₃Adding the nanobelt solution and dopamine hydrochloride into a deionized water solution of trihydroxymethyl aminomethane, fully and uniformly stirring at room temperature, washing, and drying to obtain a flower-shaped Mo-polydopamine composite (Mo-PDA); sintering the obtained product in an inert atmosphere to obtain the superfine MoO uniformly bridged in the flaky carbon matrix₂Electrode material of nanoparticles.

According to the scheme, the MoO₃The preparation method of the nanobelt solution comprises the following steps:

1) mixing Mo powder with H₂O₂And H₂Stirring the mixture in the O mixed solution uniformly;

2) transferring the solution obtained in the step 1) into a reaction container for heating, taking out, and naturally cooling to room temperature to obtain MoO₃Nanobelt solution.

According to the scheme, the time for fully stirring is 2-8 h.

According to the scheme, the mass of the Mo powder in the step 1) is 0.5-3.5 g; h in the mixed solution₂O₂And H₂O two are 10-80mL each.

According to the scheme, the MoO₃The nano-belt solution is 1-10mL, the dopamine hydrochloride is 0.1-1g, the tris (hydroxymethyl) aminomethane is 0.1-1g, and the deionized water is 20-200 mL.

According to the scheme, the heating temperature is 160-200 ℃, and the heating time is 6-48 h;

according to the scheme, the sintering temperature is 600-1000 ℃, and the sintering time is 1-4 h.

The inside of the flaky carbon matrix is uniformly bridged with ultrafine MoO₂The nano-particle electrode material is applied as a negative electrode active material of a lithium ion battery with high capacity and long cycle life.

The invention designs a delicate nano microstructure, and the flaky carbon matrix is used as an electron transport network and an electrode active substance (MoO) at the same time₂) A carrier providing good conductivity to the electrode material and internal MoO during charging and discharging₂The nanoparticles provide good buffering of volume expansion, stabilizing their microstructure, and at the same time, due to the carbon to MoO₂Confinement effect of particle size such that MoO₂Can maintain its size below 3nm even after high temperature treatment, and greatly reduce MoO₂The volume of the nanoparticles expands during charging and discharging. MoO₂Compared with the traditional supported point contact, the embedded structure of the nano particles and the carbon matrix greatly improves the contact area of the active material and the conductive network, greatly improves the conduction of electrons/ions in the microstructure and bridged MoO₂The nanoparticles are also beneficial to constructing a lithium ion transmission channel, and the structure endows the electrode material with excellent electron/ion conduction capability and structural stability. When the material is used as a negative electrode material and tested, the current density is 200mA g^-1The capacity is 810mAh g^-1(ii) a When the current density is 1.0A g^-1At all, even after 1000 cycles, the capacity is still480mAh g^-175% of the capacity is maintained.

In addition, ultrafine MoO is uniformly bridged in the flaky carbon matrix₂The electrode material of the nano particles is synthesized by a sol-gel method, the process is simple, the nano microstructure of the electrode material can be controlled by changing the concentration of reactants, the reaction temperature and the reaction time, and the work provides a scheme for the structural design of the next generation of long-circulation and high-energy density materials.

The invention has the beneficial effects that: based on the unique advantages of the structure under the nanometer scale, the superfine MoO is uniformly bridged in the flaky carbon matrix₂The nano-particle electrode material shows excellent cycling stability and high capacity when being used as a lithium ion negative electrode material through a simple synthesis method, and is a potential application material of a lithium ion battery with high capacity and long cycle life.

Drawings

FIG. 1 shows the ultrafine MoO uniformly bridged inside the flaky carbon matrix of example 1 of the present invention₂XRD pattern of electrode material of nanoparticles;

FIG. 2 shows the ultrafine MoO uniformly bridged inside the flaky carbon matrix of example 1 of the present invention₂SEM images of the electrode material of the nanoparticles;

FIG. 3 shows the ultrafine MoO uniformly bridged inside the flaky carbon matrix of example 1 of the present invention₂TEM images of the electrode material of the nanoparticles;

FIG. 4 shows the ultrafine MoO uniformly bridged inside the flaky carbon matrix of example 1 of the present invention₂A synthesis mechanism diagram of the electrode material of the nano-particles;

FIG. 5 shows the ultrafine MoO uniformly bridged inside the flaky carbon matrix of example 1 of the present invention₂HRTEM of the electrode material of the nanoparticles;

FIG. 6 shows the ultrafine MoO uniformly bridged inside the flaky carbon matrix of example 1 of the present invention₂STEM map of the electrode material edge region of the nanoparticles;

FIG. 7 shows the ultrafine MoO uniformly bridged inside the flaky carbon matrix of example 1 of the present invention₂A low magnification STEM map of the electrode material of the nanoparticles and a partially magnified STEM map thereof;

FIG. 8 is an embodiment of the present inventionUltrafine MoO uniformly bridged inside the flaky carbon matrix of example 1₂High magnification STEM plot of electrode material of nanoparticles;

FIG. 9 shows the ultrafine MoO uniformly bridged inside the flaky carbon matrix of example 1 of the present invention₂High current density cycling profile of nanoparticle electrode material (current density of 1A g)^-1)。

Detailed Description

While the following is a description of the preferred embodiments of the present invention, it should be noted that those skilled in the art can make various modifications and improvements without departing from the principle of the embodiments of the present invention, and such modifications and improvements are considered to be within the scope of the embodiments of the present invention.