In₂O₃ Nanoparticles on Three-Dimensionally Ordered Macroporous (3DOM) Carbon for Pseudocapacitor Electrodes

We present a facile sol-gel approach for the fabrication of In₂O₃/3DOM carbon nanocomposites for pseudocapacitor applications. By this facile chemical method, uniform In₂O₃ nanoparticles can be vertically grown on the surface of 3DOM carbon. The structure and morphology of the material is characterized by X-ray diffraction, nitrogen gas sorption, scanning electron microscope, and transmission electron microscope techniques. Cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) are used to investigate the electrochemical performance of electrodes. An In₂O₃/3DOM carbon electrode with 10 wt.% shows a high specific capacitance of 287 F g^-1, while the capacitance of In₂O₃ electrode alone is 58 F g^-1. Furthermore, an In₂O₃/3DOM carbon nanocomposite pseudocapacitor shows a stable cycle life in the potential range of 0-0.5 V and retains 86% of its initial capacitance over 5000 cycles. The high specific capacitance and excellent cycle life are due to the three-dimensionally ordered pore structure of the carbon, which favors the diffusion of the electrolyte ions and provides a conductive scaffold.