CN107937966B

CN107937966B - In-situ preparation method of iron-based hydroxide pseudo-capacitor film material

Info

Publication number: CN107937966B
Application number: CN201711030474.0A
Authority: CN
Inventors: 樊玉欠; 王璐萌; 戴维; 李子轩; 张文波; 曾磊
Original assignee: Yanshan University
Current assignee: Yanshan University
Priority date: 2017-10-30
Filing date: 2017-10-30
Publication date: 2020-01-07
Anticipated expiration: 2037-10-30
Also published as: CN107937966A

Abstract

An in-situ preparation method of an iron-based hydroxide pseudocapacitance film material mainly comprises the following steps: (1) cleaning, dedusting and deoiling a metal iron matrix to obtain a clean iron surface; (2) preparing an electrolyte solution for in-situ preparation, wherein a solvent is deionized water, a solute component is metal alkali, and an additive is alkali chloride; (3) immersing a cleaned iron matrix serving as a working electrode into an electrolyte solution, adding a graphite electrode serving as a counter electrode into the electrolyte solution, and continuously activating the surface of the iron matrix by a conventional electrochemical oxidation-reduction technology, namely constant current step or pulse voltage step to circularly activate the iron electrode, so that a layer of iron-based hydroxide film material with high pseudo-capacitance activity can be obtained on the surface of the iron matrix. The method has the advantages of cheap raw materials, simple process, easy operation and low production cost, and the prepared film product has high electrochemical pseudocapacitance energy storage activity and is suitable for industrial mass production.

Description

In-situ preparation method of iron-based hydroxide pseudo-capacitor film material

Technical Field

The invention relates to a preparation method of a film material.

Background

Electrochemical energy storage devices have increasingly important applications in modern society, such as in the fields of electric vehicles (electric cars ), small mobile devices (cell phones, notebooks), industrial emergency power supplies, and the like. The batteries which can be widely applied at present are lead-acid storage batteries and lithium ion batteries. The main problems of lead-acid batteries are their low power density, short cycle life and the possibility of heavy metal pollution. The main problems of lithium ion batteries are low power density, insufficient cycle life, high cost and important potential safety hazards (flammability and explosiveness). Aiming at the problems, the development of the electrode material with high power density, long cycle life, low cost and low potential safety hazard has important application significance.

The pseudocapacitance material based on the electrode interface active substance rapid reversible oxidation-reduction reaction has high power density and ultra-long cycle lifeAnd the like, and thus becomes the current on-heating point. At present, the development of transition metal oxide products is mainly focused at home and abroad, for example: NiO, MnO₂，Co₃O₄And the like. Although the activity of the product is high, the cost of raw materials is relatively high, and the product is not beneficial to industrial production and large-scale application.

Iron-based compound pseudocapacitance materials gradually receive the attention of researchers in recent years, and the main reason is that iron is the most popular, cheap and easily available raw material in production and life, and the application prospect of the iron-based compound pseudocapacitance materials is very good. However, the main problems of the iron-based compound material at present are that the preparation process is complex, the activity is low, and the stability is poor. In addition, most of the iron-based pseudocapacitance materials reported at present are powder materials, the conductivity is poor, and an additional electrode preparation process needs to be introduced, so that the application of the iron-based pseudocapacitance materials is inconvenient.

Disclosure of Invention

The invention aims to provide the in-situ preparation method of the iron-based hydroxide pseudocapacitance film material, which has the advantages of cheap raw materials, simple process, easiness in operation, low production cost, short production period, high pseudocapacitance activity and suitability for industrial mass production.

The technical scheme of the invention is as follows:

(1) cleaning, dedusting and deoiling a metal iron matrix to obtain a clean iron surface;

the iron matrix is flat plate iron or a porous iron matrix;

(2) preparing an electrolyte solution for in-situ preparation, wherein a solvent is deionized water, a solute component is metal alkali, and an additive is alkali chloride; OH in electrolyte solution^-Concentration of 1-5mol/L, Cl^-The concentration is 0.5-3 mol/L;

the metal alkali is one or two of KOH and NaOH, and the mass percentage of the KOH in the two types of metal alkali is 10-30%;

the alkali metal chloride is one or two of KCl and NaCl, and the mass percentage of KCl is 10-30% in the two cases;

(3) and (3) immersing the cleaned iron matrix serving as a working electrode into the electrolyte solution prepared in the step (2), adding a graphite electrode serving as a counter electrode into the electrolyte solution, and continuously activating the surface of the iron matrix by using a conventional electrochemical oxidation-reduction technology, namely constant current step or pulse voltage step, so as to circularly activate the iron electrode, thereby obtaining a layer of iron-based hydroxide film material with high pseudocapacitance activity on the surface of the iron matrix.

Compared with the prior art, the invention has the following advantages:

1. cheap raw materials, simple process, easy operation and low production cost.

2. The production period is short, the pseudo-capacitance activity of the prepared product is high, and the method is suitable for industrial mass production.

Drawings

FIG. 1 is a scanning electron microscope image of the pseudocapacitance film of iron-based hydroxide obtained in example 1 of the present invention.

FIG. 2 is a graph showing the charge-discharge curve of the pseudo-capacitor film made of the iron-based hydroxide obtained in example 1 of the present invention (current density: 50 mA/cm)²)。

Detailed Description

Example 1

First, a commercial porous iron substrate was washed with deionized water and ethanol to remove dust and oil, respectively, to obtain a clean iron surface; secondly, KOH alkaline electrolyte is prepared, and the KOH concentration is 60g/L (in this case, OH)^-Concentration of 1mol/L), additive NaCl, and mass concentration of 60g/L (Cl)^-The concentration is 1 mol/L); then, the cleaned iron electrode is used as a working electrode and is immersed into the electrolyte, and the graphite electrode is used as a counter electrode and is added into the electrolyte. By means of a conventional constant current step technique (current density: 50 mA/cm)²And the time is controlled to be 150s) to circularly activate the iron electrode, so that a layer of iron-based hydroxide pseudocapacitance film material can be obtained on the surface of the iron matrix.

As shown in fig. 1, it can be seen that the prepared iron hydroxide thin film material has a stacked porous structure and is uniformly distributed. FIG. 2 is the charge and discharge curve of the film material in 1mol/L KOH electrolyte solution, the charge and discharge current is 50mA/cm²It can be seen that the thin film material exhibits excellent area specific capacitance.

Example 2

First, commercial iron foil was washed with deionized water and ethanol to remove dust and oil, respectively, to obtain a clean iron surface; secondly, NaOH alkaline electrolyte is prepared, and the concentration of NaOH is 200g/L (OH at the moment)^-5mol/L concentration), KCl as additive, and 37g/L mass concentration (Cl)^-The concentration is 0.5 mol/L); then, immersing the cleaned iron electrode serving as a working electrode into electrolyte, and adding the graphite electrode serving as a counter electrode into the electrolyte; a layer of iron-based hydroxide pseudocapacitance film material can be obtained on the surface of an iron matrix by circularly activating an iron electrode through a conventional constant potential step technique (step voltage window is-2V, time is controlled at 150 s).

Example 3

First, commercial iron foil was washed with deionized water and ethanol to remove dust and oil, respectively, to obtain a clean iron surface; secondly, preparing NaOH + KOH alkaline electrolyte with NaOH concentration of 40g/L (OH at the moment)^-The concentration is 5mol/L), the KOH concentration is 4g/L, the additive is KCl and NaCl, the mass concentration of NaCl is 60g/L (Cl)^-The concentration is 0.5mol/L), the KCl concentration is 6 g/L; then, immersing the cleaned iron electrode serving as a working electrode into electrolyte, and adding the graphite electrode serving as a counter electrode into the electrolyte; a layer of iron-based hydroxide pseudocapacitance film material can be obtained on the surface of an iron matrix by circularly activating an iron electrode through a conventional constant potential step technique (step voltage window is-2V, time is controlled at 150 s).

Example 4

First, commercial iron foil was washed with deionized water and ethanol to remove dust and oil, respectively, to obtain a clean iron surface; secondly, preparing NaOH + KOH alkaline electrolyte with NaOH concentration of 40g/L (OH at the moment)^-The concentration is 5mol/L), the KOH concentration is 12g/L, the additive is KCl and NaCl, the mass concentration of NaCl is 60g/L (Cl)^-The concentration is 0.5mol/L), the KCl concentration is 18 g/L; then, immersing the cleaned iron electrode serving as a working electrode into electrolyte, and adding the graphite electrode serving as a counter electrode into the electrolyte; by means of a conventional constant current step technique (current density: 50 mA/cm)²Time is controlled to be 150s) pairsAnd (3) circularly activating the iron electrode to obtain a layer of iron-based hydroxide pseudo-capacitance film material on the surface of the iron matrix.

Claims

1. An in-situ preparation method of an iron-based hydroxide pseudocapacitance film material is characterized by comprising the following steps: it comprises the following steps:

(2) preparing an electrolyte solution for in-situ preparation, wherein a solvent is deionized water, a solute comprises one or two of KOH and NaOH, the mass percentage of the KOH is 10-30% and an additive is alkali metal chloride; OH in electrolyte solution^-Concentration of 1-5mol/L, Cl^-The concentration is 0.5-3 mol/L;

(3) immersing a cleaned iron substrate serving as a working electrode into the electrolyte solution prepared in the step (2), adding a graphite electrode serving as a counter electrode into the electrolyte solution, and carrying out conventional constant current step technique, wherein the current density is as follows: 50mA/cm²And controlling the time at 150s, and performing cyclic activation on the iron electrode to obtain a layer of iron-based hydroxide film material with high pseudo-capacitance activity on the surface of the iron matrix.

2. The in-situ preparation method of the iron-based hydroxide pseudocapacitance film material according to claim 1, which is characterized by comprising the following steps of: the iron matrix is flat plate iron or a porous iron matrix.

3. The in-situ preparation method of the iron-based hydroxide pseudocapacitance film material according to claim 1, which is characterized by comprising the following steps of: the alkali metal chloride is one or two of KCl and NaCl, and the mass percentage of the KCl is 10-30% in the two types.