Electrochimica Acta, Vol.132, 490-495, 2014
High Performance Flexible Pseudocapacitor based on Nano-architectured Spinel Nickel Cobaltite Anchored Multiwall Carbon Nanotubes
We demonstrate a facile two-step fabrication method for nano-architectured spinel nickel cobaltite (NiCo2O4) anchored multiwall carbon nanotubes (MWCNTs) based electrodes for high performance flexible energy-storage devices. As electrode materials for flexible supercapacitors, the NiCo2O4 anchored MWCNTs exhibits a high specific capacitance of 2032 Fg(-1), which is nearly 1.62 times greater than pristine NiCo2O4 nanoflakes at 1 Ag-1. The synthesized NiCo2O4 anchored MWCNTs composite shows excellent rate performance (83.96% capacity retention at 30 Ag-1) and stability with coulombic efficiency over 96% after 5,000 cycles when being fully charged/discharged at 1 Ag-1. Furthermore, NiCo2O4 anchored MWCNTs achieve a maximum energy density of 48.32 Whkg(-1) at a power density of 480 Wkg(-1) which is 60% higher than pristine NiCo2O4 electrode and significantly outperformed electrode materials based on NiCo2O4 which are currently used in the state-of-the-art supercapacitors throughout the literature. This superior rate performance and high-capacity value offered by NiCo2O4 anchored MWCNTs is mainly due to enhanced electronic and ionic conductivity, which provides a short diffusion path for ions and an easy access of electrolyte flow to nickel cobaltite redox centers besides the high conductivity of MWCNTs. (C) 2014 Elsevier Ltd. All rights reserved.
Keywords:Spinel nickel cobaltite;nano-architectured;Multiwall Carbon Nanotubes;flexible energy storage devices;supercapacitors