Microwave Preparation Of Nickel Oxidel Matrix Composites For Supercapacitors

Supercapacitors,as a new energy storage device which performance is between secondary battery and conventional capacitors,have attracted the attention of scientists due to the advantages of high power density,fast charge and discharge rate and high energy density.As the core material of supercapacitors,electrode materials directly determine the performance of supercapacitors.As an electrode material for supercapacitors,transition metal oxides have been extensively studied since their discovery due to their high theoretical specific capacitance.As a kind of transition metal oxide,NiO has outstanding advantages such as natural abundance,low price,green and environmentally friendly.However,the disadvantage of low conductivity limits its application.NiO is often combined with other materials to obtain supercapacitors with superior performance.As a new synthetic method,solid-phase microwave method has advantages such as simple operation,short reaction time and no post-treatment,compared with traditional methods,such as hydrothermal method and chemical deposition method.Therefore,in this paper,using high electrical and thermal conductivity as the heating layer,we prepared PPy/NiO and MWGO/NiO composites via solid-state microwave approach.The main tasks are as follows:?1?We successfully prepared PPy/NiO composite by solid-state microwave approach,which was employed Ni?NO₃?₂·6H₂O as the precursor and PPy as microwave absorbing material,which were prepared by oxidative polymerization.The XRD and FTIR patterns illustrated that the precursor of Ni²⁺was decomposed into nickel oxide by a microwave reaction while being supported on the surface of the polypyrrole.According to the SEM image,both polypyrrole and nickel oxide were nanoparticles.The effects of material mass ratio,microwave power and microwave time on the electrochemical performance of PPy/NiO electrode materials were investigated.The experimental results showed when the mass ratio of substrate to precursor at50:40,800w of the microwave power and 60s of microwave heating time,the PPy/NiO electrode performances were the best,and the maximum specific capacitance was 450 Fg^-11 at 0.5Ag^-1.It shows better cycle stability with about82%of the initial specific capacitance value after 400 cycles.?2?We successfully prepared MWGO/NiO composite via solid-state microwave approach,which used Ni?NO₃?₂·6H₂O as the precursor and GO as microwave absorbing material,which were prepared by modified hummers.The XRD and FTIR patterns illustrated that MWGO was successful reduced and the precursor of Ni²⁺was decomposed into nickel oxide by a microwave reaction while being supported on the surface of the graphene.According to the SEM image,nickel oxide was nanoparticles.The effects of material mass ratio,microwave power and microwave time on the electrochemical performance of MWGO/NiO electrode materials were investigated.The experimental results showed when the mass ratio of substrate to precursor at50:40,1000w of the microwave power and 2min of microwave heating time,the MWGO/NiO electrode performances were the best,and the maximum specific capacitance was360.5 Fg^-11 at 1Ag^-1.It shows better cycle stability with about 94%of the initial specific capacitance value after 1000 cycles.