Facile synthesis of Ce-doped α-cobalt hydroxide nanoflakes battery type electrode with an enhanced capacitive contribution for asymmetric supercapacitors

Abstract

The nanostructure of layered cobalt hydroxide has been gaining increasing attention in the field of electrochemical energy storage due to its high surface area and compatible cages for the redox reactions. Nevertheless, its poor electrical conductivity hinders application toward rate performance. In this work, cerium (Ce)-doped α-cobalt hydroxide (α-Co(OH)2) thin-film electrodes were prepared with improved rate capability via electrodeposition method. To investigate the effect of Ce doping on the structural, morphological and electrochemical properties of α-Co(OH)2, it was doped in different molar percentages ranging from 0 to 3 mol%. The α-Co(OH)2 doped with 1 mol% Ce showed an excellent charge storage performance with a specific capacity of 415 C g−1 and the relatively higher cyclic stability of 73%. The deconvolution of capacitive and diffusion-controlled contributions has been performed using step potential electrochemical spectroscopy which showed the capacitive contribution of the film increased from 38% to 45% when doped with Ce by 1 mol%. This improved capacitive contribution of α-Co(OH)2 battery-type electrode can facilitate high power performance without compromising the specific energy of the supercapacitor. Finally, this electrode was employed for the fabrication of asymmetric supercapacitor that showed excellent cyclic stability, specific energy and power.