Assembly of Ni(OH)2-based electrodes without material synthesis step for application in supercapacitors

Abstract In this work, a facile material synthesis step-free strategy for the cost-effective assembly of Ni(OH) 2 -based electrodes was reported. The Ni(OH) 2 /MWCNTs composite electrodes for application in supercapacitors were assembled through the in-situ reaction of NiCl 2 ·6H 2 O in nickel foam as current collector with alkaline electrolyte. The characterization results indicated that NiCl 2 ·6H 2 O as raw material in electrode underwent the phase transformation from NiCl 2 ·6H 2 O to β-Ni(OH) 2 in electrolyte solution. The produced β-Ni(OH) 2 presented the same phase and same sheet morphology with thin thickness before and after electrochemical measurement. Based on the results of electrochemical measurement, 20 wt% was determined as the optimum content of MWCNTs for the assembly of electrodes. The as-assembled electrode with optimized content of MWCNTs exhibited high specific capacitance of 2001.4 F g −1 at current density of 3.2 A g −1 . This electrochemical performance of electrode could be attributed to the 2D flexible sheet morphology of Ni(OH) 2 and the improvement of electric conductivity by MWCNTs. Graphical abstract