Preparation And Performance Of Flexible Electrode Materials For Supercapacitors

With the progress of science and technology,people have higher requirements for the performance of electronic products.The electronic products with flexible,portable and wearable characteristics have been greatly welcomed.As a new energy storage device,flexible supercapacitors（FSCs）have good flexibility,which makes it possible for electronic devices to be portable and wearable.Compared with other flexible electrode materials,biomass-based flexible electrode materials have the advantages of low cost,environmental friendliness and renewability,and thus have wider application prospects.However,the inherent problems of poor conductivity and low porosity of biomass-based flexible materials often limit their development.Appropriate experimental methods are needed to improve the properties of biomass-based flexible materials and to obtain biomass-based flexible materials with good electrochemical properties.Based on the above background,this paper has done the following research work:Firstly,using cotton fabrics as precursor material.C/Ni composite porous carbon fibers were prepared by impregnating cotton fabric with nickel acetate and calcining them.The sample obtained by impregnation with 5%nickel acetate solution and carbonization of 800°C has good flexibility and optimum electrochemical performance.The morphology and structure were characterized by XRD,Raman,XPS,SEM and BET.The sample has a high degree of graphitization.Nickel metal nanoparticles are embedded on the surface of the fibers and a large number of pores exist.Its specific surface area is 373.1 m² g^-1.At a current density of 1 A g^-1,the specific capacitance reaches 100.1 F g^-1.After 5000 cycles of charge and discharge tests,the specific capacitance loss was only 5.2%.Secondly,the raw materials were treated by three different methods:soaking soymilk,soaking soymilk after NaOH swelling and soaking soymilk containing 2-methylimidazole,and then calcining them,three kinds of flexible carbon fiber anode materials with different morphologies were prepared.The results of characterization show that these three dipping methods have changed the graphitization degree and microstructure of carbon materials in varying degrees.All three methods have greatly improved the electrochemical properties.The specific capacitances of the three electrodes at 1 A g^-1 are 71.2 F g^-1,81.1 F g^-1 and 91.5 F g^-1,respectively,and the ratio performance was good.After 5000 cycles of testing,78.9%,89.1%and 94.0%specific capacitance were retained respectively.Finally,calcining carbon cloth dipped by different acetates and etching them by hydrochloric acid,the porous carbon fibers were obtained.The results showed that the porous carbon fiber film obtaines by dipping with cobalt acetate has the best electrochemical properties.The film has a high degree of graphitization,good fiber continuity and a large number of pores on the surface.And it has super flexibility property.It exhibits good electrochemical performance with a specific capacitance up to 123.4 F g^-1 at current densitiy of 1 A g^-1 and an eminent cycling stability with a 95.0%retains after 10000 cycles.