The nanosheets interconnected highly porous CoxNi1-xO (0.025 <= x <= 0.1) was successfully synthesized via hydrothermal route. The effect of Co on the structural, morphological and electrochemical properties of NiO has been examined for supercapacitor (SC) application. Scanning electron microscope (SEM) images display the formation of porous networks. Scanning transmission electron microscope (STEM) images confirm the arrangement of nanosheets leads to flower like porous networks. Co0.05Ni0.95O exhibits the maximum specific capacity of 582 C g(-1) (161.67 mA h g(-1)) at a specific current of 1 A g(-1). Galvanostatic charge discharge (GCD) analysis reveals the maximum energy density of 39.54 W h kg(-1) with the power density of 17.11 kW kg(-1), and observed cyclic stability is 96% even after 1500 continuous charge/discharge cycles for Co0.05Ni0.95O. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.