Carbon-coated mesoporous NiO nanoparticles as an electrode material for high performance electrochemical capacitors

A rational design has resulted in the large-scale synthesis of amorphous carbon coated mesoporous NiO (denoted as NiO@C) nanocomposites through a hydrothermal method. The mesoporous characteristics of as-synthesized NiO@C nanocomposites provide an ultrahigh active surface area and thus significantly enhance the intercalation of ions and the utilization rate of electrode materials, while the carbon shell within the nanocomposites improves greatly the electron conductivity of the overall electrode. Being beneficial for a strong synergistic effect between NiO and carbon materials, the mesoporous NiO@C nanocomposites as high-performance pseudocapacitors exhibited a high specific capacitance of 931 F g(-1) at 2 A g(-1) and a long-term cycling stability (similar to 7% loss after 6000 cycles), as compared with NiO (707 F g(-1) at 2 A g(-1) and similar to 13% loss after 6000 cycles).