Distinguished from commonly used Fe2O3 and Fe3O4,a three-dimensional multilevel macromicro-mesoporous structure of FeC2O4/graphene composite has been prepared as binderfree electrode for supercapacitors.The as-prepare...Distinguished from commonly used Fe2O3 and Fe3O4,a three-dimensional multilevel macromicro-mesoporous structure of FeC2O4/graphene composite has been prepared as binderfree electrode for supercapacitors.The as-prepared materials are composed of macroporous graphene and microporous/mesoporous ferrous oxalate.Generally,the decomposition voltage of water is 1.23 V and the practical voltage window limit is about 2 V for asymmetric supercapacitors in aqueous electrolytes.When FeC2O4/rGO hydrogel was used as the negative electrode and a pure rGO hydrogel was used as the positive electrode,the asymmetrical supercapacitor voltage window raised to 1.7 V in KOH(1.0 mol/L)electrolyte and reached up to 2.5 V in a neutral aqueous Na2SO4(1.0 mol/L)electrolyte.Correspondingly it also exhibits a high performance with an energy density of 59.7 Wh/kg.By means of combining a metal oxide that owns micro-mesoporous structure with graphene,this work provides a new opportunity for preparing high-voltage aqueous asymmetric supercapacitors without addition of conductive agent and binder.展开更多
A kind of sandwich-like NiCo_2O_4/rGO/NiO heterostructure composite has been successfully anchored on nickel foam substrate via a three-step hydrothermal method with successive annealing treatment. The smart combinati...A kind of sandwich-like NiCo_2O_4/rGO/NiO heterostructure composite has been successfully anchored on nickel foam substrate via a three-step hydrothermal method with successive annealing treatment. The smart combination of NiCo_2O_4, reduced graphene oxide(rGO), and NiO nanostructure in the sandwich-like nano architecture shows a promising synergistic effect for supercapacitors with greatly enhanced electrochemical performance. For serving as supercapacitor electrode, the NiCo_2O_4/rGO/NiO heterostructure materials exhibit remarkable specific capacitance of 2644 mF cm^(-2)at current density of 1 mA cm^(-2),and excellent capacitance retentions of 97.5% after 3000 cycles. It is expected that the present heterostructure will be a promising electrode material for high-performance supercapacitors.展开更多
文章以氧化石墨烯(GO)为原料,通过溶剂热法制备钴铁氧体/还原氧化石墨烯复合材料(CoFe_2O_4/rGO)。利用透射电子显微镜(transmission electron microscope,TEM)、高分辨透射电子显微镜(high-resolution transmission electron microscop...文章以氧化石墨烯(GO)为原料,通过溶剂热法制备钴铁氧体/还原氧化石墨烯复合材料(CoFe_2O_4/rGO)。利用透射电子显微镜(transmission electron microscope,TEM)、高分辨透射电子显微镜(high-resolution transmission electron microscope,HRTEM)、场发射扫描电子显微镜(field emission scanning electron microscope,FESEM)、X射线衍射仪(X-ray diffraction,XRD)等对其进行表征,并研究其对模拟有机染料废水的吸附性能。结果表明:所制备的CoFe_2O_4/rGO复合材料为具有核壳结构的球形纳米颗粒,其平均粒径约为180nm;CoFe_2O_4/rGO能高效吸附阴离子有机染料,对刚果红吸附量高达490.6mg/g,其吸附作用主要是由静电作用力引起的。展开更多
基金supported by the National Natural Science Foundation of China (No.51673180 and No. 51673180)
文摘Distinguished from commonly used Fe2O3 and Fe3O4,a three-dimensional multilevel macromicro-mesoporous structure of FeC2O4/graphene composite has been prepared as binderfree electrode for supercapacitors.The as-prepared materials are composed of macroporous graphene and microporous/mesoporous ferrous oxalate.Generally,the decomposition voltage of water is 1.23 V and the practical voltage window limit is about 2 V for asymmetric supercapacitors in aqueous electrolytes.When FeC2O4/rGO hydrogel was used as the negative electrode and a pure rGO hydrogel was used as the positive electrode,the asymmetrical supercapacitor voltage window raised to 1.7 V in KOH(1.0 mol/L)electrolyte and reached up to 2.5 V in a neutral aqueous Na2SO4(1.0 mol/L)electrolyte.Correspondingly it also exhibits a high performance with an energy density of 59.7 Wh/kg.By means of combining a metal oxide that owns micro-mesoporous structure with graphene,this work provides a new opportunity for preparing high-voltage aqueous asymmetric supercapacitors without addition of conductive agent and binder.
基金supported by the Special Fund for the Development of Strategic Emerging Industries of Shenzhen City of China(No.JCYJ20140419141154246)the National Nature Science Foundation of China(No.11174227)Chinese Universities Scientific Fund
文摘A kind of sandwich-like NiCo_2O_4/rGO/NiO heterostructure composite has been successfully anchored on nickel foam substrate via a three-step hydrothermal method with successive annealing treatment. The smart combination of NiCo_2O_4, reduced graphene oxide(rGO), and NiO nanostructure in the sandwich-like nano architecture shows a promising synergistic effect for supercapacitors with greatly enhanced electrochemical performance. For serving as supercapacitor electrode, the NiCo_2O_4/rGO/NiO heterostructure materials exhibit remarkable specific capacitance of 2644 mF cm^(-2)at current density of 1 mA cm^(-2),and excellent capacitance retentions of 97.5% after 3000 cycles. It is expected that the present heterostructure will be a promising electrode material for high-performance supercapacitors.
文摘文章以氧化石墨烯(GO)为原料,通过溶剂热法制备钴铁氧体/还原氧化石墨烯复合材料(CoFe_2O_4/rGO)。利用透射电子显微镜(transmission electron microscope,TEM)、高分辨透射电子显微镜(high-resolution transmission electron microscope,HRTEM)、场发射扫描电子显微镜(field emission scanning electron microscope,FESEM)、X射线衍射仪(X-ray diffraction,XRD)等对其进行表征,并研究其对模拟有机染料废水的吸附性能。结果表明:所制备的CoFe_2O_4/rGO复合材料为具有核壳结构的球形纳米颗粒,其平均粒径约为180nm;CoFe_2O_4/rGO能高效吸附阴离子有机染料,对刚果红吸附量高达490.6mg/g,其吸附作用主要是由静电作用力引起的。
