One-step preparation of Co3O4/C/Ni(OH)2@NF electrode for high performance supercapacitor

Abstract

Energy storage devices (Supercapacitor and battery) make it possible to substitute endless and clean new energy sources including solar, wind and tidy energy (disadvantage: discontinuous and unstable) for limited fossil resources, and wireless electric-driven for wire electric-driven. Energy storage devices also play key roles in developing electric-driven tools including automobiles and advanced equipment, e.g., unmanned aerial vehicles (UAV) and robots. The above utilization is strongly dependent on the performance of the energy storage device, especially the electrode. Herein, a new strategy is suggested to synthesize, construct and load the activated material of Co3O4/C/Ni(OH)2 on the conductive Ni foam in one hydrothermal step, i.e., the electrode is directly prepared. By introducing glutamic acid, which acts as a weak oxidant for NF, a complex agent for Co2+ ions, as well as a carbon source, a composite electrode of Co3O4/C/Ni(OH)2@NF is easily built. As-prepared Co3O4/C/Ni(OH)2@NF has excellent supercapacitor performance: Its electrode has a specific capacitance of 2963.68 mF cm−2 at 2 mA cm−2, and capacitance retention of 105 % after 5000 cycles, while its asymmetric supercapacitor (ASC) provides an energy density of 301.22 μWh cm−2 at the power density of 1.88 mW cm−2.