Cobalt–Nickel Oxides with Three-Dimensional Hexagon Films for High Performance Supercapacitors

Cobalt–nickel oxide electrode materials with three-dimensional hexagon films or flower-shaped structures have been synthesized by a chemical precipitation method at different thermal decomposition temperatures. Nickel ions enter into the lattice of Co 3 O 4 by forming solid solution and promote primary nanoparticles partly self-assemble into three-dimensional hexagon films which interlace with each other to form a flower-like structure. Consequently, cobalt–nickel oxide with a Ni/Co mole ratio of 1:6 at 220[Formula: see text]C displays a highest capacitance of 796.16[Formula: see text]F/g at 200[Formula: see text]mA/g and cobalt–nickel oxide with a Ni/Co mole ratio of 1:3 at 200[Formula: see text]C exhibits a highest capacitance of 290[Formula: see text]F/g at 10[Formula: see text]A/g, which significantly improve the electrochemical properties of Co 3 O 4 .