A capacitor electrode and a method for preparing the capacitor electrode by electrodeposition

Abstract

The present invention relates to the technical field of capacitor material preparation, and in particular to a method for preparing capacitor electrodes by electrodeposition. The present invention provides a method for preparing a non-uniform electrode with good electrochemical performance and weak storage capacity, using cleaned and dried nickel foam as a working electrode, and using SeO 2 With H 2 O to form selenite H 2 SeO 3 solution, and then electrodeposited NiCoSe on the nickel foam surface. 2 The first electrodeposition is performed at a preset voltage in a first solution containing Ni ions, Co ions and Se ions; the electrodeposition is repeated in a second solution containing Ni ions and Co ions to prepare NiCo-LDH until the prepared NiCo-LDH exhibits a non-uniform structure; the NiCo-LDH is electrodeposited at the same preset voltage so that the NiCo-LDH is deposited on the NiCoSe 2 surface to prepare NiCoSe2 and NiCo‑LDH electrode materials.

Description

Technical Field

[0001] The present invention relates to the technical field of capacitor material preparation, and in particular to a method for preparing capacitor electrodes by using an electrodeposition method. Background Art

[0002] With the development of the energy industry, energy storage devices have attracted more and more attention. Compared with batteries as new energy storage devices, capacitors have higher power density, better cycle performance stability and better rate performance. Electrode materials are an important component of supercapacitors and one of the core components of device safety. It is particularly important to prepare an electrode material with a reasonable structure and excellent composition ratio.

[0003] Transition metal compounds have attracted much attention due to the high theoretical specific capacitance that researchers have;

[0004] Among them, binary metal compounds show good electrochemical properties, especially NiCo bimetallic compounds have become the ideal electrode materials;

[0005] Nickel-cobalt layered double hydroxide (NICO-LDH) is a two-dimensional layered metal oxide, a type of layered double hydroxide (LDHS). It is composed of nickel (Nì), cobalt (Co) and oxygen (O), and has a layered structure similar to other LDHs.

[0006] N ICO-LDH has certain chemical stability and physical and chemical properties, and has a wide range of application potential in catalysis, adsorption, electrochemistry and other fields. Its layered structure provides a large number of active sites and a large specific surface area, which is conducive to catalytic reactions, adsorption processes and ion transport. In addition, it also has good ion exchange properties and can be used in ion exchange resins, battery materials and other fields.

[0007] In addition, it is known from previous reports that the construction of heterostructures is beneficial to the performance of electrode materials.

[0008] Due to the differences in the electronic band structures between the components of the heterostructure, a built-in electric field is spontaneously formed at the inhomogeneous interface, which accelerates the charge transfer and increases the galvanic rate of the heterostructure. In addition, the directional transfer of electrons between the heterophases leads to a local charge rearrangement in the interface region, which further enhances the adsorption of hydroxides by the heterostructure due to electrostatic interactions. Summary of the invention

[0009] The present invention provides a method for preparing a non-uniform electrode having good electrochemical performance and weak storage capacity, specifically providing a capacitor electrode and a method for preparing the capacitor electrode by an electrodeposition method.

[0010] In order to solve the above technical problems, the technical solutions of the present invention are as follows:

[0011] A method for preparing a capacitor electrode by electrodeposition, comprising:

[0012] Step S1, using the cleaned and dried nickel foam as the working electrode, using SeO2 and H2O to form a selenious acid H2SeO3 solution, and constructing an electrodeposition on the surface of the nickel foam, so that Se2 - Produce electroreduction;

[0013] Step S2, performing a first electrode deposition on NiCoSe2 in a first solution containing Ni ions, Co ions and Se ions at a preset voltage; the preset voltage is -1V;

[0014] Step S3, repeatedly electrodepositing in a second solution containing Ni ions and Co ions to prepare NiCo-LDH until the prepared NiCo-LDH exhibits a non-uniform structure;

[0015] Step S4, electro-depositing NiCo-LDH at the same preset voltage so as to be deposited on the surface of Ni CoSe2, thereby preparing an electrode material of NiCoSe2 and Ni Co-LDH;

[0016] After step S5 is completed, the product is rinsed with deionized water and ethanol respectively and then dried to obtain the electrode material;

[0017] The lattice spacing of the electrode material is 0.152nm;

[0018] Wherein, the Ni CoSe2 is granular and uniform on the surface of the nickel foam.

[0019] Specifically, in step S1, the cleaning method is to use deionized water, dilute hydrochloric acid, anhydrous ethanol, and acetone for ultrasonic cleaning respectively; the cleaning time is 30 to 55 minutes respectively, and the mass fraction of the dilute hydrochloric acid is 2 to 10%.

[0020] Specifically, in the step S1, the mass concentration of the selenious acid H2SeO3 solution is 2-10 g / L.

[0021] Specifically, in the first solution, the concentration range of nickel ions is 5 to 9 g / L; the concentration range of cobalt ions is 8 to 10 g / L.

[0022] Specifically, the electrodeposition temperature of the electrodeposition is 45 to 75°C.

[0023] Specifically, a cyclic voltammetry test is performed on the electrode material, the current density of the test is 50 mA / cm2, and the number of cycles is 5000.

[0024] Specifically, the prepared electrode material is dried and used as a sample, and an X-ray photoelectron spectroscopy analysis test is performed on the sample electrode material, and the test substrate is carbon cloth.

[0025] A capacitor electrode adopts the method for preparing the capacitor electrode by using the electrodeposition method, wherein the electrode is NiCoSe2 and NiCo-LDH, and the ultra-micro morphology of the electrode is composed of nanosheets and particles.

[0026] The present invention has the following beneficial effects:

[0027] On the one hand, the technical solution effectively constructs a heterostructured electrode material on the surface of nickel foam by two-step electrodeposition. The electrode material can effectively accelerate the electron transfer rate due to the self-generated electric field, and NiCo-LDH can provide a larger specific surface area to obtain better electrochemical performance.

[0028] In addition, due to the good stability and specific capacitance between NiCoSe2 and NiCo-LDH, it has good electrochemical performance and weak storage capacity.

[0029] Secondly, the electrode in this technical solution shows excellent electrochemical performance, and the electrode exhibits a high specific capacitance (3250mF / cm 2 , 5mA / cm 2 ) and excellent capacity retention (88% at 5000 cycles). BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0031] Figure 1 It is a schematic diagram of the process of the present invention;

[0032] Figure 2 Schematic diagram of the curve of Ni intensity and electron volt;

[0033] Figure 3 Schematic diagram of the curve of Co intensity and electron volt;

[0034] Figure 4 is a schematic diagram of the curve of Se intensity and electron volt;

[0035] Figure 5 Schematic diagram for preparing electrode materials;

[0036] Figure 6It is an embodiment of the change of current and potential;

[0037] Figure 7 An embodiment of taking values ​​of a curve of potential versus time;

[0038] Figure 8 is the curve of current and potential change;

[0039] Fig. 9 is the curve of potential versus time; DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention; the purpose of such description is to clearly express the technical solution, and it should not be understood as an improper limitation on the technical solution of this application.

[0041] The present invention provides a method for preparing a non-uniform electrode having good electrochemical performance and weak storage capacity, specifically providing a capacitor electrode and a method for preparing the capacitor electrode by an electrodeposition method. First, the method for preparing the capacitor electrode by an electrodeposition method comprises:

[0042] Step S1, using the cleaned and dried nickel foam as the working electrode, using SeO2 and H2O to form a selenious acid H2SeO3 solution, and constructing an electrodeposition on the surface of the nickel foam, so that Se2 - Produce electroreduction;

[0043] Step S2, performing a first electrode deposition on NiCoSe2 in a first solution containing Ni ions, Co ions and Se ions at a preset voltage; the preset voltage is -1V;

[0044] Step S3, repeatedly electrodepositing in a second solution containing Ni ions and Co ions to prepare NiCo-LDH until the prepared NiCo-LDH exhibits a non-uniform structure;

[0045] Step S4, electro-depositing NiCo-LDH at the same preset voltage so as to be deposited on the surface of Ni CoSe2, thereby preparing an electrode material of NiCoSe2 and Ni Co-LDH;

[0046] After step S5 is completed, the product is rinsed with deionized water and ethanol respectively and then dried to obtain the electrode material;

[0047] The lattice spacing of the electrode material is 0.152nm;

[0048] Wherein, the Ni CoSe2 is granular and uniform on the surface of the nickel foam.

[0049] Specifically, in step S1, the cleaning method is to use deionized water, dilute hydrochloric acid, anhydrous ethanol, and acetone for ultrasonic cleaning respectively; the cleaning time is 30 to 55 minutes respectively, and the mass fraction of the dilute hydrochloric acid is 2 to 10%.

[0050] Specifically, in the step S1, the mass concentration of the selenious acid H2SeO3 solution is 2-10 g / L.

[0051] Specifically, in the first solution, the concentration range of nickel ions is 5 to 9 g / L; the concentration range of cobalt ions is 8 to 10 g / L.

[0052] Specifically, the electrodeposition temperature of the electrodeposition is 45 to 75°C.

[0053] Specifically, a cyclic voltammetry test is performed on the electrode material, the current density of the test is 50 mA / cm2, and the number of cycles is 5000.

[0054] Specifically, the prepared electrode material is dried and used as a sample, and an X-ray photoelectron spectroscopy analysis test is performed on the sample electrode material, and the test substrate is carbon cloth.

[0055] A capacitor electrode adopts the method for preparing the capacitor electrode by using the electrodeposition method, wherein the electrode is NiCoSe2 and NiCo-LDH, and the ultra-micro morphology of the electrode is composed of nanosheets and particles.

[0056] Example 1, Preparation process of NiCoSe2 and NiCo-LDH Since SeO2 can react with H2O to form H2SeO3, Se 2- Electroreduction can be produced in the following cases: NiCoSe2 was first electrodeposited at a voltage of -1 V in a solution containing Ni ions, Co ions, and Se ions; then, the electrodeposition was repeated in a solution containing Ni ions and Co ions to prepare NiCo-LDH and construct high-performance heterostructure electrode materials.

[0057] As attached Figure 2 , 3 As shown in Figures 4 and 5, the granular NiCoSe2 can be uniformly deposited on the surface of nickel foam at a voltage of -1V, and the distribution is uniform. Secondly, NiCo-LDH is uniformly electrodeposited on the surface of NiCoSe2 at the same voltage. It can be seen that NiCo-LDH has a layered microstructure, as shown in the attached figure. Figure 6 As shown; the lattice spacing of the electrode material is 0.152nm.

[0058] Example 2, in order to test the lattice structure of the sample, the XRD test was used for analysis, the carbon cloth was used as the test substrate, and the electrode material was composed of NiCo-LDH and NiCoSe2; the valence state composition of the surface of each element electrode material was further verified, and the sample surface was analyzed using XPS. Figure 3 It shows that Ni3+ and Ni2+ exist on the surface of the sample.

[0059] Embodiment 3, Figure 7 Therefore, it can be more certain that the electrode material has better electrochemical performance. In addition, it can be seen from Figure 7 The oxidation and reduction peaks in the electrode material store charge through redox reactions.

[0060] Embodiment 4, it can be from Figure 8 , 9 It can be seen that the composite electrode material shows excellent electrochemical performance under different scan rates and current densities. Figure 8 , Fig. 9 It can be seen that NiCoSe2 has a good rate performance, which has a positive effect on improving the electrochemical performance of the electrode material. The composite electrode material has a small resistance, indicating that it has good conductivity. In order to further estimate the composite electrode, the cycle test was carried out at a current density of 50 mA / cm 2 The composite electrode material showed good stability. After 5000 cycles, the capacity retention rate reached 88% and the Coulombic efficiency exceeded 99%.

[0061] In conclusion, we have successfully and efficiently fabricated a composite electrode material by two-step electrodeposition. Due to the rational structural design and built-in self-generated electric field, the electrode material exhibited good electrochemical performance and energy storage capacity, showing a specific capacity of 3250 mF / cm 2 , and the current is 5mA / cm 2 .

[0062] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for preparing a capacitor electrode by electrodeposition, characterized in that: include: Step S1, using the cleaned and dried nickel foam as the working electrode, using SeO2 and H2O to form a selenious acid H2SeO3 solution, and constructing an electrodeposition on the surface of the nickel foam, so that Se2 - Produce electroreduction; Step S2, performing a first electrode deposition of NiCoSe2 in a first solution containing Ni ions, Co ions and Se ions at a preset voltage; the preset voltage is -1V; Step S3, repeatedly electrodepositing in a second solution containing Ni ions and Co ions to prepare NiCo-LDH, until the prepared NiCo-LDH exhibits a non-uniform structure; Step S4, electro-depositing NiCo-LDH at the same preset voltage so that it is deposited on the surface of NiCoSe2, thereby preparing electrode materials of NiCoSe2 and NiCo-LDH; After step S5 is completed, the product is rinsed with deionized water and ethanol respectively and then dried to obtain the electrode material; The lattice spacing of the electrode material is 0.152nm; Wherein, the NiCoSe2 is granular and uniform on the surface of the nickel foam.

2. The method for preparing a capacitor electrode by electrodeposition as claimed in claim 1, characterized in that: In the step S1, the cleaning method is to use deionized water, dilute hydrochloric acid, anhydrous ethanol, and acetone for ultrasonic cleaning respectively; the cleaning time is 30 to 55 minutes respectively, and the mass fraction of the dilute hydrochloric acid is 2 to 10%.

3. The method for preparing a capacitor electrode by electrodeposition as claimed in claim 2, characterized in that: In the step S1, the mass concentration of the selenious acid H2SeO3 solution is 2-10 g / L.

4. The method for preparing a capacitor electrode by electrodeposition as claimed in claim 3, characterized in that: In the first solution, the concentration range of nickel ions is 5-9 g / L; the concentration range of cobalt ions is 8-10 g / L.

5. The method for preparing a capacitor electrode by electrodeposition as claimed in claim 4, characterized in that: The electrodeposition temperature of the electrodeposition is 45 to 75°C.

6. The method for preparing a capacitor electrode by electrodeposition as claimed in claim 1, characterized in that: The electrode material is subjected to a cyclic voltammetry test, wherein the current density of the test is 50 mA / cm2 and the number of cycles is 5000.

7. The method for preparing a capacitor electrode by electrodeposition as claimed in claim 1, characterized in that: The prepared electrode material is dried and used as a sample, and an X-ray photoelectron spectroscopy analysis test is performed on the sample electrode material, and the test substrate is carbon cloth.

8. A capacitor electrode, characterized in that: The invention adopts the method for preparing capacitor electrodes by electrodeposition as claimed in any one of claims 1 to 7, wherein the electrodes are NiCoSe2 and NiCo-LDH, and the ultra-micro morphology of the electrodes is composed of nanosheets and particles.

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