Study On Preparation And Energy Storage Performance Of Polyaniline Nanowire/Three-Dimensional Graphene Electrode Materials

As a new type of green energy storage conversion device,supercapacitor has the characteristics of high power density,high coulomb efficiency,fast charge and discharge speed and long cycle life.Three-dimensional graphene hollow balls?3D HGBs?inherit the advantages of graphene and effectively avoid the aggregation of graphene nanosheets.At the same time,the preparation of 3D HGBs also has the advantages of low temperature,large scale and low cost.However,due to its electric double layer capacitance mechanism,the specific capacitance is relatively low.Therefore,it is an effective method to combine 3D HGBs with conductive polymer or metal oxide with high pseudocapacitance to improve the specific capacitance of composite.Among them,polyaniline?PANI?is an excellent conductive polymer because of its high theoretical specific capacity,various redox states,and easy synthesis of various structures.In this paper,nickel nanoparticles?NiNPs?were firstly prepared by reducing NiCl₂·6H₂O with N₂H₄?H₂O,and three-dimensional graphene hollow balls?3D HGBs?were prepared using Ni NPs as template and triethylene glycol as carbon source.Then,the polyaniline nanowire arrays?PANI NWAs?were grown on the surface of the 3D HGBs by in-situ polymerization of aniline monomers to obtain polyaniline nanowire array/three-dimensional graphene hollow balls?PANI NWA/3D HGBs?.Finally,the surface of PANI NWA/3D HGBs was modified by Hexadecyl trimethyl ammonium Bromide?CTAB?to make it have positive charge,and modified PANI NWA/3D HGBs and GO with negative charge were combined by electrostatic self-assembly method to obtain PANI NWA/3D HGBs-GO composite.The results show that PANI NWAs with a length of about 200 nm were uniformly grown on 3D HGBs with a diameter of about 500 nm,and the composite has the best energy storage performance when combined with 1 mg GO on the surface of PANI NWA/3D HGBs.In a three-electrode system,the specific capacitance of the composite can reach 690.0 F/g at a current density of 1 A/g.In a two-electrode system,the energy density can reach 30.9 Wh/kg at a power density of 690.1 W/kg,and the capacity retention is 90%after 10000 charge and discharge cycles at 10.0A/g.In order to further improve the electrochemical performance of composites,three-dimensional graphene?3D GR?was prepared by chemical vapor deposition?CVD?using commercial nickel nanowires?Ni NWs?as templates,methane as carbon source.Then,PANI NWAs were grown on the surface of the 3D GR by in-situ polymerization.The results show that PANI NWAs with a length of about300-400 nm were uniformly grown on 3D GR with small pore size?1-3?m?.In a three-electrode system,the specific capacitance of the composite material can reach818.7 F/g at a current density of 1 A/g.In a two-electrode system,the energy density can reach 33.4 Wh/kg at a power density of 795.1 W/kg,and the capacity retention is87%after 10000 charge and discharge cycles at 10.0 A/g.