Assembly Of Graphene/Polyaniline Fiber Supercapacitors And Study Of The Electrochemical Properties

The development of new energy devices is essential to the development and utilization of clean green energy.As a new energy device,supercapacitors have attracted widespread attention due to its advantages such as high power density,long cycle life,fast charge and discharge,and low cost.In recent years,the development of flexible energy storage devices has led to the development of supercapacitors in terms of flexibility,lightness and thinness,and the flexibility of active electrode materials is the key to achieving high-performance flexible supercapacitors.Carbon materials and conductive polymers are currently the main electrode materials for supercapacitors.This article aims to use graphene with large specific surface area,excellent conductivity,and polymer with high theoretical specific capacitance as the active electrode materials to realize the controllable preparation of graphene/polyaniline composite flexible fibers.By constructing flexible supercapacitors based on the composite fiber electrodes,the electrochemical properties of fiber supercapacitors are systematically studied,establish the relationship between fiber electrode materials and fiber-type supercapacitors.By optimizing the microstructure and device assembly of fiber electrodes,a high-performance graphene/polyaniline flexible fiber supercapacitor is finally obtained.The main contents of this papers include:1)The graphene oxide and ammonium persulfate dispersion was prepared as a precursor based on the wet spinning technology,and the graphene oxide/polyaniline composite flexible fiber was prepared by immersing in a hydrochloric acid solution containing aniline,and the graphene/polyaniline composite flexible fiber was obtained after chemical reduction treatment;The microscopic morphology and electrochemical properties of the composites were studied.By systematically studying the key parameters of the fiber preparation process,a composite flexible fiber with the best electrochemical performance is obtained and the volume specific capacitance of the composite fiber reached to 156.5 F cm^-3 and the energy density is 5.43 m Wh cm^-3.2)Polyaniline nanofibers were prepared by a rapid mixing method,and dispersed in a graphene oxide liquid crystal solution to obtain a spinning dope,and ex-situ loaded graphene/polyaniline composite flexible fiber was obtained by wet spinning technology and chemical reduction.Furthermore,in order to effectively improve the stacking of polyaniline during ex-situ loading,DMF/H₂O was used as a co-solvent to obtain graphene/polyaniline fibers and achieves the homogeneous dispersion of polyaniline in graphene fibers.The characterization results show that polyaniline is in the needle-shaped nanostructures are present in the composite fiber.The electrochemical test and analysis of the constructed flexible fiber supercapacitor was studied,by optimizing the loading of polyaniline nanofibers,it was found that the volume specific capacitance of the electrode material reached 330 F cm^-3 and the device energy density is 7.33 m Wh cm^-3 when the mass loading ratio of graphene oxide and polyaniline was 50:1.the energy density is optimized by constructing an asymmetric supercapacitor,and the energy density of the device reaches to 25.22mWh cm^-3.