The Characteristic Of Storage And Structure Of Nickel-based Metal Organic Frameworks

Metal organic frameworks?MOFs?have been used in gas storage and classification,medical treatment,photoelectromagnetic materials and many fields.Due to its characteristics of large specific surface area and controllable pore size,MOFs as supercapacitor electrode has been reported increasingly at home and abroad.However,the stability is poor because MOFs is composed of metal ion and organic.It is difficult to achieve ideal results in practical application.If MOFs is modified reasonably,the ideal electrode material of supercapacitor can be obtained.In this paper,Ni-MOF material was used as the precursor system to prepare nickel sulfide electrode material,the effects of preparation technology and microstructure on the properties of nickel sulfide electrode were studied.The energy storage characteristics of supercapacitor electrode material were studied systematically.Spherical Ni-MOF was prepared by solvothermal method,and synthesis core-shell nickel sulfide based on Ni-MOF precursor,Ni₃S₄-80 and Ni₃S₄-100?80 and 100respectively represent the reaction temperature?were prepared respectively.Ni₃S₄-100has a core shell of 1?5?m in size,an inner sphere with a diameter of 500nm?3?m,and a shell thickness of about 100?300nm.The results showed that Ni₃S₄-100 showed better capacitive performance,and the specific capacity reached 1386 F g^-1 at the current density of 1 A g^-1.The capacity can still retention 94.6%after 500 cycles at 2A g^-1 current density.Then the all-solid supercapacitor Ni₃S₄//AC was assembled based on Ni₃S₄ anode,activated carbon?AC?cathode and PVA/KOH electrolyte.At the current density of 2 A g^-1,the specific capacitance value can reach 89.88 F g^-1 and the voltage window can reach 1.7v.With good flexibility,two solid capacitor series can be used to light LED lamp.At the same time,Carbon Cloth?CC?was used as the substrate to prepare flexible Ni-MOF/CC,and the height of the nanosheet was about 200nm.Ni-MOF/CC were used as the precursor system to prepare nano piece Ni₃S₂/CC with large specific surface area and buffer the physical stress.At 1 A g^-1 current density,the specific capacity reaches 1474 F g^-1.After 500 cycles,the specific capacitance remains 90.9%of the original value.The results showed that the Ni-MOF with two different structures prepared nickel sulfide in the precursor system had excellent electrochemical properties,and could be used in the electrode materials of supercapacitors.