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CN-119852102-B - Honeycomb ZIF-derived layered double hydroxide composite material, and preparation method and application thereof

CN119852102BCN 119852102 BCN119852102 BCN 119852102BCN-119852102-B

Abstract

The invention discloses a honeycomb ZIF-derived layered double hydroxide composite material, a preparation method and application thereof, and the honeycomb ZIF-derived layered double hydroxide composite material prepared by the invention comprises ZIF-67 and NiCo LDH, can fully exert the synergistic effect between different materials, and improves the specific capacity of an electrode. In addition, the honeycomb structure is assembled by the nano sheet structure, so that the contact area between the electrode and the electrolyte is increased, the electrochemical reaction active site is improved, the electron transmission channel is increased, the conductivity is improved, the problem that layered double hydroxide is easy to agglomerate and stack and the structure collapses in the circulating process can be solved, and the circulating performance of the electrode material is improved. The preparation method is simple to operate, good in reproducibility and easy for large-scale production.

Inventors

  • QI QI
  • CHEN XING
  • LIU HAOHAO

Assignees

  • 东南大学

Dates

Publication Date
20260512
Application Date
20231016

Claims (5)

  1. 1. A method for preparing a honeycomb ZIF-derived layered double hydroxide composite material, comprising the steps of: (1) Quickly adding a methanol solution of dimethyl imidazole into a methanol solution of cobalt nitrate, magnetically stirring and mixing, standing at room temperature, centrifuging, cleaning with methanol, and vacuum drying to obtain a polyhedral ZIF-67; (2) Dispersing ZIF-67 and Ni (NO 3 ) 2 ∙6H 2 O) in ethanol with the volume fraction of 95%, dripping ZIF-67 ethanol suspension into nickel nitrate ethanol solution at a certain reaction temperature, collecting a sample after the reaction is finished, washing with ethanol, and finally drying in vacuum to obtain a ZIF-67@NiCo LDH honeycomb composite material; In the step (1), the concentration of the methanol solution of cobalt nitrate is 50-100 g/L, the concentration of the methanol solution of 2-methylimidazole is 10-50 g/L, the mass ratio of ZIF-67 to Ni (NO 3 ) 2 ∙6H 2 O) in the step (2) is 1 (2-3), the concentration of ZIF-67 in the ZIF-67 suspension in the step (2) is 1-4 g/L, the concentration of Ni (NO 3 ) 2 ∙6H 2 O) in the nickel nitrate ethanol solution in the step (2) is 5-15 g/L, the reaction temperature in the step (2) is 25-35 ℃, and the reaction time is 1-9 hours.
  2. 2. The ZIF-67@NiCo LDH honeycomb composite material prepared by the preparation method of claim 1.
  3. 3. Use of the ZIF-67@nico LDH honeycomb composite material according to claim 2 for the preparation of a composite electrode.
  4. 4. The use according to claim 3, wherein the preparation of the composite electrode comprises uniformly mixing the ZIF-67@NiCo LDH honeycomb composite material with polytetrafluoroethylene and acetylene black to form a slurry, and coating the slurry on the pretreated foam nickel, wherein the loading amount of the slurry is 0.8-1.5 mg/cm 2 .
  5. 5. A ZIF-67@nico LDH composite electrode, comprising the ZIF-67@nico LDH honeycomb composite material of claim 2.

Description

Honeycomb ZIF-derived layered double hydroxide composite material, and preparation method and application thereof Technical Field The invention belongs to the technical field of super capacitor energy storage, and particularly relates to a honeycomb ZIF-derived layered double hydroxide composite electrode, and a preparation method and application thereof. Background Environmental pollution and exhaustion of fossil energy are two major problems facing mankind today, and the intensive development of clean and renewable energy is a hot spot of research in the world today. Development of super capacitors with high conversion efficiency and long-term stability is one of the important strategies for scientifically utilizing clean energy and realizing the sustainable promotion of social development by renewable energy. Designing the electrodes of the multicomponent and multidimensional structure is a key technology for assembling the efficient supercapacitor. Layered Double Hydroxides (LDHs) are widely used as supercapacitor electrode materials due to their high theoretical capacity, large specific surface area, good redox activity, and the like. However, the problems of low electron conductivity, reduced number of exposed active sites due to easy layered aggregation and accumulation, and blockage of electrolyte ion transport channels in the practical process have prevented the possibility of large-scale application. The multi-component can fully utilize the synergistic effect among different components to provide a plurality of reversible metal ion redox couples. The three-dimensional structure assembled by the nano-sheets can avoid the aggregation and accumulation of LDH, increase the specific surface area of the material, expose more electrochemical active sites and shorten the distance of electron and ion transmission. Meanwhile, the honeycomb structure fully utilizes the internal space of substances and the expansion of the volume of the buffer electrode in the charge and discharge process, so that the specific capacity and the circulation stability of the electrode are effectively improved. Therefore, it is desirable to develop a new composite electrode material capable of significantly improving the electrochemical properties of the material. Disclosure of Invention The invention aims to solve the technical problem of providing a novel honeycomb-structured layered double hydroxide composite material with excellent electrochemical performance. The invention also solves the technical problem of providing a method for preparing a honeycomb ZIF-derived layered double hydroxide composite material by utilizing an ion exchange method. The invention finally solves the technical problem of providing the application of the layered double hydroxide composite electrode material with the honeycomb structure in the preparation of the composite electrode material. The invention provides a preparation method of a honeycomb ZIF-derived layered double hydroxide composite material, which comprises the following steps of: (1) Quickly adding a methanol solution of dimethyl imidazole into a methanol solution of nitrate, magnetically stirring and mixing, standing at room temperature, centrifuging, cleaning with methanol, and vacuum drying to obtain a polyhedral ZIF-67; (2) And respectively dispersing ZIF-67 and Ni (NO 3)2·6H2 O) in ethanol with the volume fraction of 90-95%, dropwise adding ZIF-67 ethanol suspension into nickel nitrate ethanol solution at a certain reaction temperature, collecting a sample after the reaction is finished, washing with ethanol, and finally drying in vacuum to obtain the ZIF-67@NiCo LDH honeycomb composite material. Further researches show that the honeycomb structure can be obtained by reacting ethanol with the volume fraction of 90-95% so as to obtain a high-performance composite material, when ethanol with the volume fraction of 80% and other volumes fractions is adopted, other composite materials with different morphologies are obtained, when the volume fraction of the ethanol is more than 95%, a hollow polyhedral structure assembled by nano sheets is obtained, when the volume fraction of the ethanol is 90-95%, a honeycomb structure assembled by nano sheets is obtained, when the volume fraction of the ethanol is less than 90%, an irregular block material is obtained, and the morphology difference is mainly caused by the fact that the sample ion exchange rate is low when the water content is low, the nano sheet structure is formed, the ion exchange rate is accelerated along with the increase of the water content, the nano sheet structure assembled by nano sheets is formed, and when the water content is more than 10%, the ion exchange only occurs on the surface of the material, and the nano sheet structure cannot be obtained. Wherein in the step (1), the concentration of the methanol solution of the cobalt nitrate is 50-100 g/L, and the concentration of the methanol solution of the 2-methylimidazo