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 Co3O4 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 degrees C displays a highest capacitance of 796.16 F/g at 200 mA/g and cobalt-nickel oxide with a Ni/Co mole ratio of 1:3 at 200 degrees C exhibits a highest capacitance of 290 F/g at 10 A/g, which significantly improve the electrochemical properties of Co3O4.