【作者】 李桂林； 张漩； 徐彩玲；

【Author】 LI Guilin;ZHANG Xuan;XU Cailing;Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province,College of Chemistry and Chemical Engineering,Lanzhou University;

【机构】 甘肃省有色金属化学与资源利用重点实验室,兰州大学化学化工学院；

【摘要】 Inspired by the advantages of the 3D graphene network for energy storage,the current research is always directed towards 3D transition metal oxide/graphene composites,whereas 3D transition metal sulfide/graphene composites are rarely studied.In this present work,3D Ni_xCo_1-xS₂ /graphene composite hydrogels with different Co/Ni molar ratios(denoted as Ni_xCo_1-x/GH（x=0,0.25,0.33,0.5,0.67,1）) have been synthesized via hydrothermal method and were utilized as the active materials of supercapacitors for comparative study of their electrochemical properties.FESEM and TEM images show that the entire samples present interconnected 3D porous network with the pore sizes from several to tens micrometers,which strongly facilitate charge and ion transport in the full electrode.And the Ni_xCo_1-xS₂ particles are uniformly located on the graphene nanosheets and the particle size is evolved from-50 nm to-1.5 μm with the increase of Ni content.The electrochemical measurements revealed that the bimetallic Ni_xCo_1-xS₂/GH electrodes exhibit better electrochemical performance than that of pure Ni₂S/GH or Co₂S/GH electrode,which benefits from the synergic effects of Co and Ni element.Moreover,their specific capacitance,cyclability and rate capability are strongly affected by their different Ni content.Among these,the 3D Ni_0.33Co_0.67S₂/GH electrode has the highest specific capacitance of 1166 F/g at a current density of 1A/g.Furthermore,a specific capacitance of 559 F/g can be still maintained at high current density of 20 A/g.After 1000 charge-discharge cycles at 5 A/g,72.6%of initial specific capacitance can be retained.This study adds a new dimension to the application of 3D graphene composite hydrogels and the development of high performance energy storage systems.更多还原

【Abstract】 Inspired by the advantages of the 3D graphene network for energy storage,the current research is always directed towards 3D transition metal oxide/graphene composites,whereas 3D transition metal sulfide/graphene composites are rarely studied.In this present work,3D Ni_xCo_1-xS₂ /graphene composite hydrogels with different Co/Ni molar ratios(denoted as Ni_xCo_1-x/GH（x=0,0.25,0.33,0.5,0.67,1）) have been synthesized via hydrothermal method and were utilized as the active materials of supercapacitors for comparative study of their electrochemical properties.FESEM and TEM images show that the entire samples present interconnected 3D porous network with the pore sizes from several to tens micrometers,which strongly facilitate charge and ion transport in the full electrode.And the Ni_xCo_1-xS₂ particles are uniformly located on the graphene nanosheets and the particle size is evolved from-50 nm to-1.5 μm with the increase of Ni content.The electrochemical measurements revealed that the bimetallic Ni_xCo_1-xS₂/GH electrodes exhibit better electrochemical performance than that of pure Ni₂S/GH or Co₂S/GH electrode,which benefits from the synergic effects of Co and Ni element.Moreover,their specific capacitance,cyclability and rate capability are strongly affected by their different Ni content.Among these,the 3D Ni_0.33Co_0.67S₂/GH electrode has the highest specific capacitance of 1166 F/g at a current density of 1A/g.Furthermore,a specific capacitance of 559 F/g can be still maintained at high current density of 20 A/g.After 1000 charge-discharge cycles at 5 A/g,72.6%of initial specific capacitance can be retained.This study adds a new dimension to the application of 3D graphene composite hydrogels and the development of high performance energy storage systems.更多还原