The demand for a new generation of high-safety, long-lifespan, and high-capacity power sources increases rapidly with the growth of energy consumption in the world. Here we report a facile method for preparing architecture materials made of NiO/Ni x Co 3Àx O 4 porous nanosheets coupled with NiO/Ni x Co 3Àx O 4 porous nanowires grown in situ on nickel foams using a hydrothermal method without any binder followed by a heat treatment process. The nanosheet-shaped NiO/Ni x Co 3Àx O 4 species in the nanosheet matrix function well as a scaffold and support for the dispersion of the Ni x Co 3Àx O 4 nanowires, resulting in a relatively loose and open structure within the electrode matrix. Among all composite electrodes prepared, the one annealed in air at 300 C displays the best electrochemical behavior, achieving a specific capacitance of 270 mF cm À2 at 5 mA cm À2 while maintaining excellent stability (retaining z 89% of the max capacitance after 20 000 cycles), demonstrating its potential for practical application in power storage devices. Fig. 2 (a) XPS survey spectrum, (b) the high-resolution XPS spectrum of Ni 2p, (c) the high-resolution XPS spectrum of Co 2p, and (d) XPS spectrum of O 1s for the NiO/Ni x Co 3Àx O 4 nanostructures.This journal is