Facile synthesis of three-dimensional structured carbon fiber-NiCo2O4-Ni(OH)2 high-performance electrode for pseudocapacitors.

Xiaojie Lou,Qida Liu,Mingshu Zhao,Lipeng Xin,Wei Li,Shujiang Ding,Ming Zhang,Xin Xu

doi:10.1038/srep09277

Abstract

Two-dimensional textured carbon fiber is an excellent electrode material and/or supporting substrate for active materials in fuel cells, batteries, and pseudocapacitors owing to its large surface area, high porosity, ultra-lightness, good electric conductivity, and excellent chemical stability in various liquid electrolytes. And Nickel hydroxide is one of the most promising active materials that have been studied in practical pseudocapacitor applications. Here we report a high-capacitance, flexible and ultra-light composite electrode that combines the advantages of these two materials for pseudocapacitor applications. Electrochemical measurements demonstrate that the 3D hybrid nanostructured carbon fiber–NiCo2O4–Ni(OH)2 composite electrode shows high capacitance, excellent rate capability. To the best of our knowledge, the electrode developed in this work possesses the highest areal capacitance of 6.04 F cm−2 at the current density of 5 mA cm−2 among those employing carbon fiber as the conductor. It still remains 64.23% at 40 mA cm−2. As for the cycling stability, the initial specific capacitance decreases only from 4.56 F cm−2 to 3.35 F cm−2 after 1000 cycles under a current density of 30 mA cm−2.

Highlights

Two-dimensional textured carbon fiber is an excellent electrode material and/or supporting substrate for active materials in fuel cells, batteries, and pseudocapacitors owing to its large surface area, high porosity, ultra-lightness, good electric conductivity, and excellent chemical stability in various liquid electrolytes
Electrochemical measurements demonstrate that the 3D hybrid nanostructured carbon fiber (CF)–NiCo2O4–Ni(OH)[2] electrode shows a high capacitance with excellent rate capability and good cycling stability
The typical low-magnification scanning electron microscopy (SEM) micrograph (Fig. 2b) clearly illustrates that the 3D hybrid nanostructured supporting material is composed of numerous needle-like NiCo2O4 with a sharp tip uniformly arranged on the CF surface

Summary

Introduction

Two-dimensional textured carbon fiber is an excellent electrode material and/or supporting substrate for active materials in fuel cells, batteries, and pseudocapacitors owing to its large surface area, high porosity, ultra-lightness, good electric conductivity, and excellent chemical stability in various liquid electrolytes. Most of the investigations have focused on utilizing metals (e.g., Ni foil, Ni foam, Ti foil, Cu foil, etc.) as the current collector and transition metal oxides (e.g., NiO, NiOH, CoO, Co4O3, NiCo2O4, MnO2) as active materials to fabricate high-performance electrodes of pseudocapacitors[9,10,11,12,13,14,15]. Nickel Cobalt Sulfide directly deposited on carbon fiber shows high specific capacitance of 1418 F g21 at 5 A g21 with excellent rate capability[24] These studies have very excellent achievements, it is still necessary and of great significance to unceasingly improve the electrode performances of pseudo-capacitors to meet the ever increasing social needs. Electrochemical measurements demonstrate that the 3D hybrid nanostructured CF–NiCo2O4–Ni(OH)[2] electrode shows a high capacitance with excellent rate capability and good cycling stability

Methods

Results

Discussion

Conclusion