Hierarchical α-Ni(OH)2 grown on CNTs as a promising supercapacitor electrode

Abstract

Metal hydroxides are welcomed in supercapacitor electrode applications. However, pristine metal hydroxides usually suffer from disadvantages of poor conductivity or agglomeration which may hinder their utilization. Hierarchical α-Ni(OH)2/CNTs hybrid is fabricated through one-step water bath method. Hierarchical α-Ni(OH)2 grows along the direction of CNTs backbones. The electrochemical performance of α-Ni(OH)2/CNTs hybrid is superior to pristine α-Ni(OH)2 according to electrochemical tests. High specific capacitance of the composite electrode reaches 2325 F g−1 at a sweep rate of 1 mV s−1. Furthermore, longer cycle life of the hybrid is achieved. The hybrid displays 83.6% specific capacitance retention after 10000 cycles in contrast to pristine α-Ni(OH)2 with only 49.5% capacitance retention. Hierarchical α-Ni(OH)2/CNTs composite with remarkable electrochemical performance may attribute to synergistic effects: good conductivity, redox property and high charge storage capacity. It is beneficial for the hybrid to get better electron storage capacity because of the Schottky barrier formed at interface between α-Ni(OH)2 and CNTs. Those properties demonstrate that the hybrid has a potential application as supercapacitor electrode.