阅读说明：本技术 一种超级电容器电极材料及其制备方法 (Super capacitor electrode material and preparation method thereof ) 是由 袁明月 余天 张兆伟 梁焯禧 李彤 黄小燕 张志友 王苛 于 2019-09-27 设计创作，主要内容包括：本发明公开了一种超级电容器电极材料及其制备方法,属于能源存储材料及器件技术领域。本发明采用电化学沉积法在双通绝缘模板中分别制备具有不同孔径和长度的过渡金属纳米管阵列,再通过一体化方法制备出具有双层同轴管状结构的过渡金属/金属原生氧化物纳米有序阵列,该双层同轴管状结构过渡金属/金属原生氧化物纳米有序阵列材料可应用为高性能超级电容器电极材料。(The invention discloses a super capacitor electrode material and a preparation method thereof, and belongs to the technical field of energy storage materials and devices. The invention adopts an electrochemical deposition method to respectively prepare transition metal nanotube arrays with different apertures and lengths in a double-pass insulating template, and then prepares a transition metal/metal native oxide nano-ordered array with a double-layer coaxial tubular structure by an integrated method, wherein the transition metal/metal native oxide nano-ordered array material with the double-layer coaxial tubular structure can be applied to high-performance supercapacitor electrode materials.)

1. An electrode material for a supercapacitor, comprising: the nano double-layer tube array grows vertically and is distributed on the conducting layer in order; the nano double-layer tube array is a nano coaxial tube array prepared by a double-pass insulating template, and the nano double-layer tube comprises a transition metal nano tube layer and a transition metal oxide nano tube layer growing on the inner wall of the transition metal nano tube layer;

the transition metal nanotube layer is transition metal or an alloy thereof, and the transition metal oxide nanotube layer is native oxide of the transition metal or the alloy thereof corresponding to the transition metal nanotube layer.

2. The supercapacitor electrode material according to claim 1, wherein the transition metal nanotube layer is Ni, Co, Fe, Mn or an alloy thereof, and the transition metal oxide nanotube layer is a native oxide of Ni, Co, Fe, Mn or an alloy thereof.

3. The supercapacitor electrode material according to claim 2, wherein the transition metal nanotube layer is Mn_1-aFe_aOr Ni_1-bFe_bWherein, 0<a<1，b<1; the transition metal oxide nanotube layer is NiO, CoO, Co₂O₃、Co₃O₄、Mn₂O₃、MnO₂、Mn₃O₄、CoFeO₄And NiFeO₄One or more combinations thereof.

4. The supercapacitor electrode material according to claim 1, wherein the template aperture Φ of the double-pass insulating template_T50 nm-2000 nm, axial length d of template_T20 nm-500 mu m; thickness d of the conductive layer_CLNot larger than the aperture phi of the template_T。

5. the supercapacitor electrode material according to claim 1, wherein the double-pass insulating template is an alumina template, a titania template, a porous silicon template or an organic porous template; the conducting layer is arranged on one surface of the double-pass insulating template and is an inactive metal film, an organic conducting film, an inorganic non-metal conducting film or an organic-metal composite film.

6. the supercapacitor electrode material according to any one of claims 1 to 5, wherein the nano-bilayer tube has an inner diameter of 10nm to Φ_TWall thickness d 'of the transition metal nanotube layer'_TMIs 3nm to d_TMWall thickness d of the transition metal oxide nanotube layer_TMOxNot less than d_TM-d’_TMA difference of (d); wherein d is_TMThe wall thickness of the transition metal nanotube layer is 0<d_TM<Φ_T。

7. the electrode material of the supercapacitor according to claim 6, wherein the nano double-layer tube array has an axial length L of 50nm to d_T。

8. The method for preparing the electrode material of the supercapacitor according to any one of claims 1 to 7, comprising the steps of:

(1) Depositing a conducting layer on one surface of the double-pass insulating template by adopting a physical vapor deposition method, a chemical vapor deposition method or a spin-coating method;

(2) Preparing a transition metal nanotube layer in a pore channel of a bi-pass insulating template by adopting electrochemical deposition;

(3) preparing a transition metal oxide nanotube layer in the transition metal nanotube layer to obtain a double-layer nanotube array generated in the pore channel of the double-pass insulating template;

(4) And (4) washing the nano double-layer tube array prepared in the step (3) with deionized water, then placing the nano double-layer tube array in a reagent which can dissolve the bi-pass insulating template and does not react with the nano double-layer tube array, soaking, removing the bi-pass insulating template, then washing and drying to obtain the electrode material of the supercapacitor.

9. The preparation method of the electrode material of the supercapacitor, according to claim 8, wherein in the step (3), the method for preparing the transition metal oxide nanotube layer in the transition metal nanotube layer comprises:

(3-1): adding a buffering agent into the electrolyte system in the step (2) according to the electrolyte system Bbye diagram to adjust the pH value of the electrolyte system, and then carrying out electrochemical deposition in the transition metal nanotube layer to form a transition metal oxide nanotube layer;

Or, (3-2): cleaning the transition metal nanotube layer with the bi-pass insulating template prepared in the step (2), then soaking the transition metal nanotube layer in an oxidant solution, and carrying out oxidation reaction in the transition metal nanotube layer to generate a transition metal oxide nanotube layer;

Or, (3-3): cleaning the transition metal nano tube layer with the bi-pass insulating template prepared in the step (2), and then annealing the transition metal nano tube layer in an oxygen-containing atmosphere at an annealing temperature T_aAt 50-900 ℃ for an annealing time t_aIs 120 s-7200 s.

10. The method for preparing the electrode material of the supercapacitor according to claim 9, wherein the step (3-1) further comprises: annealing the product after the electrochemical deposition reaction at an annealing temperature T_aAt 50-900 ℃ for an annealing time t_ais 120s to 7200 s; the product is an oxide or hydroxide of a transition metal or alloy thereof.

Technical Field

The invention relates to the technical field of energy storage materials and devices, in particular to a super capacitor electrode material and a preparation method thereof.

Background

conventional energy storage devices mainly include a battery and a capacitor. Generally, a battery has a large energy storage capacity but takes a long time for charging and discharging, and a capacitor has a relatively limited energy storage capacity although the charging and discharging efficiency is high. The super capacitor has the advantages of both the battery and the capacitor, has larger energy storage capacity than the battery, keeps the high-efficiency charging/discharging capacity of the capacitor, and is a novel energy storage device with application potential.

Oxides of transition metals and their alloys are a class of supercapacitor electrode materials with high specific capacitance values. In particular based on Fe₂O₃、Co₃O₄、CoO、NiO、MnO_x(x＝4/3，3/2,2)、NiFe₂O₄The electrode material formed by the method generally has higher theoretical and experimental specific capacitance values and has industrial and application potentials.

From the material design, the high-performance supercapacitor electrode material meets the following requirements: (i) the material structure is controllable and has large specific surface area, (ii) an effective ion transport channel can be provided, (iii) a good charge conduction path is provided, (iv) the electrode material has stable structure, and (v) the preparation process is relatively convenient.

In fact, a single material is difficult to combine all the aspects, and most of common composite materials need to be assembled after being synthesized step by step, so that the preparation process of the material is complex, the stability and controllability of the structure are limited, and large-scale preparation and application are difficult to some extent.

Disclosure of Invention

The invention aims to provide a super capacitor electrode material and a preparation method thereof, and aims to solve the problems of low specific capacitance, poor charging and discharging efficiency, low energy storage capacity, poor structural stability and complex preparation of the conventional super capacitor electrode material.

The technical scheme for solving the technical problems is as follows:

An electrode material for a supercapacitor, comprising: the nano double-layer tube array grows vertically and is distributed on the conducting layer in order; the nano double-layer tube array is a nano coaxial tube array prepared by a double-pass insulating template, and the nano double-layer tube comprises a transition metal nano tube layer and a transition metal oxide nano tube layer growing on the inner wall of the transition metal nano tube layer;

The transition metal nanotube layer is transition metal or an alloy thereof, and the transition metal oxide nanotube layer is native oxide of the transition metal or the alloy thereof corresponding to the transition metal nanotube layer.

For convenience of description, the Nano double-layer Tube Array is Nano Bilayer Tube Array, abbreviated as NBTA; the Transition Metal nanotube Layer is a Transition Metal Tube Layer, abbreviated as TMTL; the transition Metal oxide nanotube Layer is a separation-Metal Oxides Tube Layer, abbreviated as TMOTL; the Nano coaxial Tube is Nano Tube, abbreviated as NT.

The invention adopts the ordered porous template, so that a plurality of nano coaxial tubes can form an ordered array vertically growing on the conducting layer; the nano double-layer tube array has a large specific surface area, can provide more reaction points, has high reaction activity and improves the charge-discharge efficiency; the hollow structure of the nano coaxial tube can provide a transmission channel for ion transportation; the transition metal nanotube layer and the transition metal oxide nanotube layer are integrally prepared, connected and compact to provide a good microscopic conductive path; the nano coaxial tube directly grows on the conducting layer, so that the nano double-layer tube array obtains an electrode with good conductivity, and the performance requirement on the electrode material of the super capacitor is met.

The transition metal of the present invention includes but is not limited to Ni, Co, Fe or Mn, and the transition metal alloy of the present invention includes but is not limited to Ni alloy, Co alloy, Fe alloy or Mn alloy. In the preparation of the transition metal nanotube layer of the present invention, a transition metal may be selected, and an alloy of the transition metal may also be selected. The transition metal oxide referred to in the present invention is a native oxide corresponding to the transition metal, that is, an oxide of Ni, Co, Fe or Mn. The transition metal alloy oxide referred to in the present invention is a native oxide of a Ni alloy, a Co alloy, a Fe alloy, or a Mn alloy. When the transition metal oxide nanotube layer of the present invention is prepared, a transition metal native oxide may be selected, or a transition metal alloy native oxide and a mixed oxide layer composed of the transition metal oxide may be selected.

Further, in an embodiment of the present invention, the transition metal nanotube layer is Ni, Co, Fe, Mn, or an alloy thereof, and the transition metal oxide nanotube layer is a native oxide of Ni, Co, Fe, Mn, or an alloy thereof.

Further, in the embodiment of the present invention, the transition metal oxide nanotube layer is NiO, CoO, Co₂O₃、Co₃O₄、Mn₂O₃、MnO₂、Mn₃O₄、CoFeO₄And NiFeO₄one or more combinations thereof.

further, in the embodiment of the present invention, the template aperture Φ of the double-pass insulating template is_T50 nm-2000 nm, axial length d of template_T20 nm-500 mu m; thickness d of the conductive layer_CLSmaller than the aperture phi of the template_T。

Template aperture phi of bi-pass insulating template_TCan be 50nm, 100nm or 2000nm, and the axial length d of the template_TIt may be 20nm, 100nm or 500 μm.

Further, in the embodiment of the present invention, the dual-pass insulating template is an aluminum oxide template, a titanium oxide template, a porous silicon template, or an organic porous template; the conducting layer is arranged on one surface of the double-pass insulating template and is an inactive metal film, an organic conducting film, an inorganic non-metal conducting film or an organic-metal composite film.

The inert metal referred to in the present invention includes, but is not limited to, Au or Pt. The inorganic non-metallic conductive film is preferably a graphite sheet.

Further, in the embodiment of the present invention, the inner diameter of the nano double-layer tube is 10nm to phi_TWall thickness d 'of the transition metal nanotube layer'_TMIs 3nm to d_TMWall thickness d of the transition metal oxide nanotube layer_TMOxNot less than d_TM-d’_TMA difference of (d); wherein d is_TMThe wall thickness of the transition metal nanotube layer is 0<d_TM<Φ_T。

The inner diameter of the nano-coaxial tube is preferably 200 nm. Thickness d 'of the transition metal nanotube layer'_TMA preferred value is 50 nm.

Further, in the embodiment of the present invention, the axial length L of the nano-double-layer tube array is 50nm to d_T. The axial length L of the nano-bilayer tube array is preferably 3 μm.

A preparation method of a supercapacitor electrode material comprises the following steps:

(1) Depositing a conducting layer on one surface of the double-pass insulating template by adopting a physical vapor deposition method, a chemical vapor deposition method or a spin-coating method;

(2) preparing a transition metal nanotube layer in a pore channel of a bi-pass insulating template by adopting electrochemical deposition;

(3) Preparing a transition metal oxide nanotube layer in the transition metal nanotube layer to obtain a double-layer nanotube array generated in the pore channel of the double-pass insulating template;

(4) And (4) washing the nano double-layer tube array prepared in the step (3) with deionized water, then placing the nano double-layer tube array in a reagent which can dissolve the bi-pass insulating template and does not react with the nano double-layer tube array, soaking, removing the bi-pass insulating template, then washing and drying to obtain the electrode material of the supercapacitor.

The conductive layer and the nano double-layer tube array are respectively prepared by adopting a physical vapor deposition method, a chemical vapor deposition method, a spin-coating method and an electrochemical deposition method, the preparation process is simple and controllable, when the nano coaxial tube is prepared by utilizing the electrochemical deposition method, the thickness of the nano coaxial tube can be adjusted by controlling the potential or current, the reaction time and the reaction temperature, and different requirements for the super capacitor can be met.

The bi-pass insulating template of the invention can select the template with the aperture of 50 nm-2000 nm and the axial length of 20 nm-500 μm, and the bi-pass insulating template is preferably an alumina template (AAO), a titanium oxide Template (TAO), a porous silicon template or an organic porous template. The transition metal oxide nanotube layer and the transition metal nanotube layer in the nano coaxial tube prepared by the template have close surface contact, and the hollow tube channel forms an excellent ion migration channel of the super capacitor.

The electrochemical deposition device preferably adopts a three-Electrode aqueous solution system electrochemical deposition device, the general device main body material is made of acid-base resistant and electrochemically stable inert materials, preferably polytetrafluoroethylene or glass, and the three electrodes are respectively a Working Electrode (WE), a Counter Electrode (CE) and a Reference Electrode (RE); the CE is preferably a platinum (Pt) mesh electrode, a graphite electrode and the like, the RE is preferably a calomel electrode or an Ag/AgCl electrode and the like, and an oxygen-free conductive copper sheet is in close contact with a conductive layer of the template to form the WE. Connecting electrodes (CE, WE and RE), injecting electrolyte prepared by salt solution of transition metal or alloy thereof, and standing for a period of time to make the electrolytic deposition solution fully wet with the double-pass insulating template with the conductive layer.

Further, in the embodiment of the present invention, in the step (3), the method for preparing the transition metal oxide nanotube layer on the inner wall of the transition metal nanotube layer includes:

(3-1): adding a buffering agent into the electrolyte system in the step (2) according to the electrolyte system Bbye diagram to adjust the pH value of the electrolyte system, and then carrying out electrochemical deposition in the transition metal nanotube layer to form a transition metal oxide nanotube layer;

Or, (3-2): cleaning the transition metal nanotube layer with the bi-pass insulating template prepared in the step (2), then soaking the transition metal nanotube layer in an oxidant solution, and carrying out oxidation reaction in the transition metal nanotube layer to generate a transition metal oxide nanotube layer;

Or, (3-3): cleaning the transition metal nano tube layer with the bi-pass insulating template prepared in the step (2), and then annealing the transition metal nano tube layer in an oxygen-containing atmosphere at an annealing temperature T_aAt 50-900 ℃ for an annealing time t_aIs 120 s-7200 s.

Further, in an embodiment of the present invention, the step (3-1) further includes: annealing the product after the electrochemical deposition reaction at an annealing temperature T_aAt 50-900 ℃ for an annealing time t_aIs 120s to 7200 s; the product is an oxide or hydroxide of a transition metal or alloy thereof.

the invention has the following beneficial effects:

The invention adopts the ordered porous template, so that a plurality of nano coaxial tubes can form an ordered array vertically growing on the conducting layer; the nano double-layer tube array structure has large specific surface area, can provide more reaction points, has high reaction activity and improves the charge-discharge efficiency; the hollow structure of the nano coaxial tube can provide a transmission channel for ion transportation; the transition metal nanotube layer and the transition metal oxide nanotube layer are integrally prepared, connected and compact to provide a good microscopic conductive path; the nanometer double-layer tube array directly grows on the conducting layer, so that the nanometer double-layer tube array obtains an electrode with good conductivity, and the performance requirement of the electrode material of the super capacitor is met.

according to the electrode material of the super capacitor, the nano double-layer tube array is directly grown on the conducting layer, so that the electrode material has good conducting capacity; the ordered porous template is adopted to ensure that the nano coaxial tubes are orderly arranged to form a nano double-layer tube array, and the hollow ordered tube channel provides an ion migration channel, so that the specific surface area is increased, the energy storage reaction points are increased, and the energy storage density is improved; the nano coaxial tube is composed of a transition metal nano tube layer with a conductive function and a transition metal oxide nano tube layer with an energy storage function, wherein the transition metal or the alloy thereof has the conductive function, the primary oxide of the transition metal or the alloy thereof has the energy storage property, and the integrated nano coaxial tube provides a good charge conduction path; the ordered nano double-layer tube array can be conveniently and integrally prepared at normal temperature and normal pressure, and is convenient for scale production.

The invention can directly obtain the ordered nano double-layer tube array by electrochemical deposition by utilizing the double-pass insulating template, and the obtained nano double-layer tube array has the energy storage property and does not need to additionally prepare and assemble a capacitor conductive structure, such as a conductive net or an electrode.

Drawings

FIG. 1 is a schematic top view of a nanocoaxial tube in an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a self-made electrochemical deposition apparatus with a three-electrode system;

FIG. 3 is a schematic flow chart of a manufacturing process according to an embodiment of the present invention; in the figure: template is a porous bi-pass insulating Template, CL (Conductive Layer, CL) is a conducting Layer of the embodiment of the invention, TMTL (Transition Metal Tube Layer) is a Transition Metal oxide Tube Layer, TMOTL (Transition Metal oxide Tube Layer) is a Transition Metal oxide Tube Layer, and NBTA (Nano double Tube Array) is a Nano double-Layer Tube Array;

FIG. 4 is a scanning electron microscope image of the supercapacitor electrode material according to example 1 of the present invention;

FIG. 5 is a scanning electron micrograph of the supercapacitor electrode material according to example 1 of the present invention;

FIG. 6 is a cyclic voltammogram in a 1M KOH electrolyte in example 1 of the present invention;

FIG. 7 shows the result of constant current charging and discharging test in the three-electrode system in example 1 of the present invention, wherein the electrolyte is 1M KOH;

FIG. 8 is a Pourbaix chart of Co in aqueous solution (Pourbaix Diagram);

FIG. 9 is a schematic representation of the preparation of Co/Co according to FIG. 7 and the protocol provided in this patent₃O₄Potential, pH and a solution system timing diagram of the electrode material of the nano double-layer tube array supercapacitor.

Detailed Description

the principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.