A reduced graphene oxide/Ni(OH)2 composite with excellent supercapacitive performance was synthesized by a facile hydrothermal route without organic solvents or templates used.XRD and SEM results reveal that the nicke...A reduced graphene oxide/Ni(OH)2 composite with excellent supercapacitive performance was synthesized by a facile hydrothermal route without organic solvents or templates used.XRD and SEM results reveal that the nickel hydroxide,which crystallizes into hexagonal β-Ni(OH)2 nanoflakes with a diameter less than 200 nm and a thickness of about 10 nm,is well combined with the reduced graphene oxide sheets.Electrochemical performance of the synthesized composite as an electrode material was investigated by cyclic voltammetry,electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements.Its specific capacitance is determined to be 1672 F/g at a scan rate of 2 mV/s,and 696 F/g at a high scan rate of 50 mV/s.After 2000 cycles at a current density of 10 A/g,the composite exhibits a specific capacitance of 969 F/g,retaining about 86% of its initial capacitance.The composite delivers a high energy density of 83.6 W·h/kg at a power density of 1.0 kW/kg.The excellent supercapacitive performance along with the easy synthesis method allows the synthesized composite to be promising for supercapacitor applications.展开更多
铁基硫酸盐因其高工作电压和低成本而成为钠离子电池(SIB)的理想正极候选材料,但其功率性能较差。针对以上问题,使用一种简易的方法,通过对氧化石墨烯进行凿孔处理,制备出多孔还原氧化石墨烯复合的Na_(2)Fe(SO_(4))_(2)@GO/C正极材料。...铁基硫酸盐因其高工作电压和低成本而成为钠离子电池(SIB)的理想正极候选材料,但其功率性能较差。针对以上问题,使用一种简易的方法,通过对氧化石墨烯进行凿孔处理,制备出多孔还原氧化石墨烯复合的Na_(2)Fe(SO_(4))_(2)@GO/C正极材料。氧化石墨烯表面富含大量的含氧官能团,在双氧水的作用下形成多孔氧化石墨烯,增大与电解液的接触面积和Na^(+)的扩散通道,使该材料具有出色的钠存储性能(0.1 C克容量为89.18 mA h·g^(-1))、优异的倍率性能(1 C克容量为77.37 mA h·g^(-1),容量保持率为86.8%,5 C克容量为56.3mA h·g^(-1),容量保持率为63%),优异的长循环性和高Na^(+)扩散系数。通过扫描电子显微镜(SEM),证实了多孔还原氧化石墨烯的可行性,通过不同扫描速率下的循环伏安曲线、拉曼测试、阻抗测试、赝电容计算,证实了该材料具有高充放电特征。展开更多
基金Project(KJ2012A045) supported by the Natural Science Foundation of Education Commission of Anhui Province,China
文摘A reduced graphene oxide/Ni(OH)2 composite with excellent supercapacitive performance was synthesized by a facile hydrothermal route without organic solvents or templates used.XRD and SEM results reveal that the nickel hydroxide,which crystallizes into hexagonal β-Ni(OH)2 nanoflakes with a diameter less than 200 nm and a thickness of about 10 nm,is well combined with the reduced graphene oxide sheets.Electrochemical performance of the synthesized composite as an electrode material was investigated by cyclic voltammetry,electrochemical impedance spectroscopy and galvanostatic charge/discharge measurements.Its specific capacitance is determined to be 1672 F/g at a scan rate of 2 mV/s,and 696 F/g at a high scan rate of 50 mV/s.After 2000 cycles at a current density of 10 A/g,the composite exhibits a specific capacitance of 969 F/g,retaining about 86% of its initial capacitance.The composite delivers a high energy density of 83.6 W·h/kg at a power density of 1.0 kW/kg.The excellent supercapacitive performance along with the easy synthesis method allows the synthesized composite to be promising for supercapacitor applications.
文摘铁基硫酸盐因其高工作电压和低成本而成为钠离子电池(SIB)的理想正极候选材料,但其功率性能较差。针对以上问题,使用一种简易的方法,通过对氧化石墨烯进行凿孔处理,制备出多孔还原氧化石墨烯复合的Na_(2)Fe(SO_(4))_(2)@GO/C正极材料。氧化石墨烯表面富含大量的含氧官能团,在双氧水的作用下形成多孔氧化石墨烯,增大与电解液的接触面积和Na^(+)的扩散通道,使该材料具有出色的钠存储性能(0.1 C克容量为89.18 mA h·g^(-1))、优异的倍率性能(1 C克容量为77.37 mA h·g^(-1),容量保持率为86.8%,5 C克容量为56.3mA h·g^(-1),容量保持率为63%),优异的长循环性和高Na^(+)扩散系数。通过扫描电子显微镜(SEM),证实了多孔还原氧化石墨烯的可行性,通过不同扫描速率下的循环伏安曲线、拉曼测试、阻抗测试、赝电容计算,证实了该材料具有高充放电特征。
