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

Abstract

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 (∼7% loss after 6000 cycles), as compared with NiO (707 F g⁻¹ at 2 A g⁻¹ and ∼13% loss after 6000 cycles).