材料科学
超级电容器
石墨烯
电极
导电体
电容
阳极
氧化物
电化学
阴极
复合材料
化学工程
纳米技术
化学
冶金
工程类
物理化学
作者
Shunhua Jiang,Jian Ding,Ronghua Wang,Yingxiong Deng,Fuyu Chen,Minquan Zhou,Hao Gui,Xinlu Li,Chaohe Xu
标识
DOI:10.1016/j.cej.2021.133936
摘要
Freestanding and binder-free electrodes with dual conductive networks were designed and prepared for asymmetric supercapacitors (ASCs), within which hollow and porous carbon nanofiber cloth (CNFs) was employed as the inner-conductive and electrochemical-active substrate while a uniform and ultrathin graphene layer served as the conductive and protective outer layer, aiming to protect the volume contraction/expansion of oxide/hydroxide during cycling and bridge the conductive path of fiber-to-fiber and (hydr)oxide-(hydr)oxide. The synergistic effect of substrate optimization, outer conductive network construction along with structural/compositional modification give rise to enhanced electronic conductivity, increased electroactive reaction sites, improved structural stability as well as accelerated kinetics, leading to remarkably rate capability and outstanding cyclic stability. Based on the weight of the whole electrode (including CNFs substrate), Fe2O3@CNFs-rGO anode achieved an outstanding specific capacitance of 488F/g at 2 A/g and excellent cycling stability of 83.5% capacitance retention after 5000 cycles at 4 A/g, whereas the specific capacitance of Ni-Co [email protected] cathode reached 932 and 396F/g at 2 and 20 A/g, respectively, showing superb rate performance. Impressively, the assembled Ni-Co [email protected]//Fe2O3@CNFs-rGO supercapacitor delivered an energy density of 45 and 18.7 Wh/kg when the power density was 1528 and 35400 W/kg, respectively. Such a reasonable structure design of electrode materials provides a new way to improve the conductivity, cycling stability and even the electrochemical performance.
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