Preparation Of Pours NiO Based On MOF-74 And Study Of Its Electrochemical Properties

With the development of society,progress of science and technology,the electrochromic-supercapacitors and flexible supercapacitors are generated along with the trend and needed to be further developed by researchers.However,the low capacity and poor cyclic stability of electrochromic-supercapacitor and flexible supercapacitor hinder their wide application.Although the above problems can be alleviated through screening of electrode materials and structural design,the volume expansion is still serious.Metal-organic frameworks(MOFs)has a series of advantages such as high specific surface area and adjustable aperture.The derived porous metal oxide electrode materials can alleviate volume expansion and improve the stability and capacity of electrode materials.Therefore,in this paper,Ni based MOF-74 is used as the precursor to prepare hierarchical porous NiO electrode materials through calcination to improve the capacity and cycling stability.The specific research contents are as follows:(1)The optimal ratio of metal ions to organic ligands was determined by SEM and XRD,and the relationship between the ratio of metal ions to organic ligands and the growth of MOF-74 films was studied.The electrochromic and capacitive properties of MOFs derived NiO films were studied and the best preparation conditions were confirmed.The electrochromic-supercapacitor was assembled by the NiO film and Fe2O3 film under the optimal conditions,and the visualization monitoring of the electric capacity storage was preliminarily realized.(2)Using the optimized preparation conditions of MOF-74 and NiO,the NiO electrode material was derived in situ on carbon cloth.The influence of the Zn Co2O4 nanosheet and NiO load on the electrochemical performance of the composite electrode was studied,and the optimal preparation conditions of the flexible electrode were confirmed.NiO/Zn Co2O4/CC electrode,Fe2O3/Zn Co2O4/CC electrode and KOH-PVA were used as the positive electrode,negative electrode,and gel electrolyte respectively to assemble the flexible supercapacitor,and the performance parameters such as working voltage window,capacity and energy density were confirmed.