Application Of High-performance Fe-Ni Based MOFs And Derivatives In Supercapacitors Cathode

With the vigorous promotion and popularization of new energy automobiles and electric buses in our country,the performance breakthrough of electrochemical energy storage equipment is crucial to the development of new energy industry in the future.Supercapacitor,as a new type of green energy storage device,has been widely applied in new energy automobiles and other fields.In this paper,according to the advantages of metal organic framework materials(MOFs),such as ordered structure,large specific surface area and uniform metal active sites,We designed some high-performance cathode materials,which have solved the problems of poor conductivity and weak cycle stability of iron-based electrode materials in supercapacitors.Then,we further improved the electrochemical performance of the cathode materials by doping and phosphating method.The specific research is divided into the following three parts:(1)Fe(BPDC)nanosheet array materials were successfully synthesized on nickel foam by simple solvothermal strategy.Fe(BPDC)exhibited excellent electrochemical performance,i.e.high specific capacitance(17.54 F/cm~2at 1 m V/s)and long cycle stability(129%after 10000 cycles).In addition,a hybrid supercapacitor was assembled by Fe(BPDC)and activated carbon(AC)as anode and cathode,which exhibited excellent energy density and power density.(2)Ni-Fe(BPDC)nanosheet array materials with better electrochemical performance were synthesized by doping nickel ions with similar radius to iron ions in solvothermal.The optimal Ni-Fe(BPDC)exhibited a high specific capacitance of27.69 F/cm~2at 1 m V/s,and a capacity retention rate of 119%after 10000 cycles.In addition,a hybrid supercapacitor was assembled by Ni-Fe(BPDC)and activated carbon(AC)to explore its performance in practical applications.(3)Based on the previous chapter,FeNiP/C composites of bimetallic phosphide and carbon was synthesized by chemical vapor deposition method,which further improved the electrochemical properties of the electrode materials.The phosphatization degree of the sample was controlled by changing the quality of the phosphorus source.The FeNiP/C electrode material exhibited a high specific of 30.57F/cm~2at 1 m V/s and a capacity retention rate of 110%after 20000 cycles.This proves that bimetallic phosphide composite materials derived from MOFs have great potential for application in supercapacitors.