阅读说明：本技术 海蜇基高表面掺杂碳电极的制备及其双电层和赝电容行为调控 (Preparation of jellyfish-based high-surface-doped carbon electrode and regulation and control of double electric layers and pseudocapacitance behaviors of jellyfish-based high-surface-doped carbon ele) 是由 王焕磊 张�浩 鹿明杰 于 2018-05-29 设计创作，主要内容包括：本发明提供了一种用于超级电容器电极的海蜇基高表面掺杂碳材料的制备手段及其双电层和赝电容行为调控方法,属于新能源材料领域。该海蜇基高表面掺杂碳材料利用碳化-活化法制备得到。首先将洗净干燥的海蜇置于管式炉中加热碳化,酸洗干燥后得到碳材料,将该碳材料与一定质量比的KOH、K<Sub>2</Sub>CO<Sub>3</Sub>、KHCO<Sub>3</Sub>、NaOH、Na<Sub>2</Sub>CO<Sub>3</Sub>、NaHCO<Sub>3</Sub>等活化剂在研钵中充分研磨后,放入管式炉中加热活化,酸洗干燥后得到海蜇基高表面掺杂碳材料。该方法制备的碳材料具有三维分层多孔结构、高比表面积、杂原子掺杂量丰富可调等特点,能通过调整制备条件对其微观结构、杂原子含量等进行调控,从而用作超级电容器电极材料时可实现对其双电层行为和赝电容行为的有效调控,实现了对超电容性能的有效增强。(The invention provides a preparation method of a jellyfish-based high-surface doped carbon material for a supercapacitor electrode and an electric double layer and pseudocapacitance behavior regulation and control method thereof, belonging to the field of new energy materials. The jellyfish-based high-surface-doped carbon material is prepared by a carbonization-activation method. Firstly, putting jellyfish which is washed and dried into a tube furnace for heating and carbonization, pickling and drying to obtain a carbon material, fully grinding the carbon material and activating agents such as KOH, K2CO3, KHCO3, NaOH, Na2CO3, NaHCO3 and the like with a certain mass ratio in a mortar, putting the ground material into the tube furnace for heating and activation, pickling and drying to obtain the jellyfish-based high-surface doped carbon material. The carbon material prepared by the method has the characteristics of three-dimensional layered porous structure, high specific surface area, rich and adjustable heteroatom doping amount and the like, and the microstructure, the heteroatom content and the like of the carbon material can be regulated and controlled by adjusting preparation conditions, so that the carbon material can realize effective regulation and control of the double electric layer behavior and the pseudo-capacitance behavior when being used as a super capacitor electrode material, and the effective enhancement of the super-capacitance performance is realized.)

1. a preparation method of a jellyfish-based high-surface-doped carbon electrode is characterized by comprising the following steps:

(1) Selection of carbon precursor: jellyfish of aquatic invertebrate in the sea is used as a precursor, the jellyfish is rich in protein and is an effective raw material for realizing the doping of heterogeneous elements such as nitrogen, oxygen and the like;

(2) Carbonizing: firstly, washing and drying jellyfish; then, putting the dried jellyfish into a tube furnace, heating to 200-1000 ℃ at the heating rate of 1-10 ℃ min < -1 > in the inert atmosphere, and preserving heat for 0-10 h for carbonization; cleaning the carbonized sample, respectively fully cleaning in diluted hydrochloric acid and distilled water with certain concentration to remove impurities, and drying in an oven to obtain a carbonized carbon material, wherein the inert atmosphere is selected from one of hydrogen, nitrogen or helium;

(3) And (3) activation: fully and mechanically grinding the carbonized carbon material and an activating agent with a certain mass ratio in a mortar, wherein the activating agent is as follows: KOH, K2CO3, KHCO3, NaOH, Na2CO3, NaHCO3 and the like, and the mass ratio of the carbonized carbon material to the activating agent is controlled to be 1: 0.1-1: 10, then putting the uniform mixture into a tubular furnace, heating to 500-1200 ℃ at a heating rate of 1-10 ℃ min < -1 > in an inert atmosphere, and keeping the temperature for 0-10 h for activation, wherein the inert atmosphere is selected from one of hydrogen, nitrogen or helium;

(4) Cleaning: and (3) cleaning the activated sample, fully cleaning the sample in dilute hydrochloric acid (0.5-5M, 20-80 ℃) and distilled water respectively to remove impurities, and drying the sample in an oven to obtain the high-surface doped carbon.

2. The preparation method of the jellyfish-based high-surface-doped carbon electrode according to claim 1, wherein the jellyfish-precursor rich in protein is used for preparing the carbon material, and the carbon material has the characteristics of high specific surface area, rich nitrogen and oxygen contents, adjustability and controllability.

3. the preparation method of jellyfish-based high surface doped carbon electrode according to claim 1-2, characterized in that the high surface doped carbon material can be applied to electrode material of super capacitor, and the regulation of surface area and content of doped element is realized by controlling carbonization and activation conditions, thereby realizing the regulation of the ratio of double electric layer capacitance and pseudocapacitance in the electrode.

Technical Field

the invention belongs to the field of new energy materials, provides a method for preparing a jellyfish-based nitrogen-oxygen doped carbon material with a high specific surface area and application thereof in a supercapacitor, and realizes regulation and control of double electric layers and pseudocapacitance behaviors of the jellyfish-based nitrogen-oxygen doped carbon material.

Background

With the growing population and the serious environmental pollution, the demand of people for efficient, clean and renewable energy sources is increasing year by year. The super capacitor has the advantages of environmental friendliness, low cost, high power density, good safety and the like, and is widely applied to the fields of electric lifting, electronic equipment, electric automobiles and the like. However, supercapacitors have a relatively low energy density compared to lithium ion batteries, which limits their usefulness. In addition, on the premise of ensuring high power density, the super capacitor with high energy density and rapid charge and discharge is required in more and more occasions, which provides great challenges for the design and preparation of super capacitor electrode materials.

The carbon material used as the electrode of the super capacitor has rich sources, adjustable structure and moderate cost, but can only provide specific capacity below 300F g-1 and poor rate capability due to the distortion of the pore channel in the carbon material, high ion diffusion resistance and low conductivity. To date, there are two typical strategies for improving the specific capacity of carbon materials. Firstly, the design of a porous structure of the carbon material can reduce the ion diffusion resistance and obtain a high surface area; and doping of heteroatoms (such as nitrogen, oxygen, sulfur and the like) can enable the carbon material to have good wettability and pseudocapacitance. For the design of the porous structure of the carbon material, the common methods are chemical activation and physical activation. The chemical activation refers to heating the mixed carbon material and an activating agent (such as KOH and the like) in an inert atmosphere, and carrying out a series of reactions to finally form the carbon material with a layered porous structure. In contrast, physical activation refers to the reaction between carbon and an oxidizing gas (e.g., air, carbon dioxide, water) at elevated temperatures to form a porous structure. Chemical activation requires shorter reaction times, lower heating temperatures and lower energy consumption than physical activation. There are two main strategies for heteroatom doping. The first is the introduction of heteroatoms from the outside, which can be achieved by calcining a heteroatom-rich compound or a mixture of gas and carbon material. For example, nitrogen doping can be obtained by heating a mixture of carbon material and urea. However, the introduction of heteroatoms in this manner may result in the destruction of the pore structure and a low amount of heteroatom doping. This is because the heteroatom is mainly attached to the surface of the carbon material rather than embedded in the carbon material, and the corresponding surface heteroatom functional group may be decomposed during the electrochemical test, resulting in a decrease in specific capacity and a deterioration in cycle stability. Compared with the first strategy, the heteroatom autodoping (the precursor containing rich heteroatoms is carbonized in inert atmosphere, and any heteroatom additive is not added in the process) is convenient to operate, and time and labor are saved. Because the heteroatom is inherited from the precursor, the heteroatom can be uniformly distributed on the surface and in the carbon matrix after heat treatment. This makes the resulting heteroatom functional group more stable, further achieving high specific capacity and good cycling stability.

in order to enhance the performance of the carbon material, a precursor rich in nitrogen and oxygen is selected, and a porous material with high specific surface area and rich heteroatom doping can be prepared by a carbonization-activation method, so that the material is very suitable for being used as an electrode material of a super capacitor. The abundant micropore and mesoporous structures contained in the material are very beneficial to charge accumulation and ion transportation, and meanwhile, the abundant nitrogen-containing and oxygen-containing functional groups contained in the material are beneficial to providing pseudo-capacitance and realizing the enhancement of the super-capacitance performance.

Disclosure of Invention

The invention aims to provide a method for preparing a nitrogen-oxygen self-doped porous carbon material by a carbonization-activation method in order to obtain a jellyfish-based carbon material with a three-dimensional layered porous structure, a high specific surface area, a high nitrogen-oxygen content, a high specific capacity and a good rate capability. The material can be used as an electrode material of a super capacitor to obtain good electrochemical performance, and the whole preparation process has the advantages of low cost, simple operation and controllable conditions.

the technical scheme adopted by the invention for solving the technical problem is as follows: jellyfish is selected as a raw material and is prepared by a carbonization-activation method. Putting the jellyfish which is cleaned and dried into a tubular furnace for heating and carbonizing; and transferring the carbonized sample into hydrochloric acid and distilled water successively, repeatedly washing for many times, and then filtering and drying to obtain the carbon material with impurities removed. And (2) fully and mechanically grinding the carbon material and activating agents such as KOH, K2CO3, KHCO3, NaOH, Na2CO3, NaHCO3 and the like in a mortar according to a certain mass ratio, then putting the uniform mixture into a tubular furnace for heating and activating, transferring the activated sample into hydrochloric acid and distilled water sequentially, repeatedly washing for multiple times, and then filtering and drying to obtain the jellyfish-based high-surface doped carbon material with impurities removed. Meanwhile, the surface area, the pore structure and the element doping amount are regulated and controlled by controlling the carbonization and activation conditions, so that the electric double layer capacitance and the pseudocapacitance behavior are controlled.

the performance of the electrode material of the supercapacitor is evaluated by a method commonly used in the field, namely, a jellyfish-based high-surface doped carbon material electrode is manufactured, and the test is carried out by utilizing the methods of cyclic voltammetry, constant current charge and discharge and electrochemical impedance.

Compared with the prior art, the invention has the beneficial effects that:

(1) The invention uses jellyfish of aquatic invertebrate in the sea as a precursor, and the protein contained in the jellyfish can effectively realize the doping of nitrogen and oxygen elements. The preparation method is simple to operate and low in cost;

(2) The jellyfish-based high-surface-doped carbon material is prepared by a carbonization-activation method, so that the obtained carbon material has a three-dimensional layered porous structure and a high specific surface area, which is beneficial to the diffusion and transportation of electrolyte ions and is the basis for obtaining excellent electrochemical properties of an electric double layer;

(3) According to the invention, nitrogen and oxygen atoms can be introduced into the carbon material, so that the wettability of the electrolyte can be improved, the conductivity can be increased, the pseudo capacitance can be introduced, and the performance of the super capacitor can be enhanced;

(4) The jellyfish-based high-surface-doped carbon material prepared by the method is used as an electrode material of a super capacitor, so that the effective regulation and control of the electric double layer capacitance and the pseudo capacitance behavior can be realized, and high specific capacity, good rate capability and excellent coulombic efficiency are obtained.

Drawings

Fig. 1 is a Scanning Electron Microscope (SEM) photograph of the jellyfish-based highly surface-doped carbon material obtained in example 1.

Fig. 2 is a Scanning Electron Microscope (SEM) photograph of the jellyfish-based highly surface-doped carbon material obtained in example 2.

Fig. 3 is a Scanning Electron Microscope (SEM) photograph of the jellyfish-based highly surface-doped carbon material obtained in example 3.

Fig. 4 is a Scanning Electron Microscope (SEM) photograph of the jellyfish-based highly surface-doped carbon material obtained in example 4.

FIG. 5 is a cyclic voltammetry curve of jellyfish-based high surface doped carbon material prepared in examples 1 to 4 of the present invention at a scan rate of 100 mV s-1.

FIG. 6 is a constant current charge and discharge curve of the jellyfish-based high surface doped carbon material prepared in examples 1-4 of the present invention at a current density of 10A g-1.

Fig. 7 is a curve of the specific capacity of the jellyfish-based high-surface-doped carbon material prepared in embodiments 1 to 4 of the present invention, which changes with current density.

Fig. 8 is a graph showing the nitrogen content, the electric double layer capacitance and the pseudocapacitance of the jellyfish-based high surface doped carbon material prepared in examples 1 to 4 of the present invention as a function of temperature.

Detailed Description

The present invention is illustrated by way of the following specific examples, which are not intended to be limiting.