Binder-Free and Flexible Carbon-Encapsulated Oxygen-Vacancy Cerium Dioxide Electrode for High-Performance Supercapacitor

Binder-free and flexible oxygen-vacancy CeO2@C core–shell nanocomposites directly anchored on carbon cloth (CC) are prepared via a simple two-step process, in which CeO2 nanoparticles are hydrothermally fabricated and mixed with polyvinylpyrrolidone (PVP) composites, subsequently, as-formed CeO2@PVP composites coated on CC are calcined at 700 °C. The morphologies, structures and electrochemical properties of as-obtained CeO2@C nanocomposites are studied by SEM, HRTEM, XRD, XPS and electrochemical techniques, respectively. The CeO2@C nanocomposites are composed of the CeO2 core with diameter of about 10 nm and the carbon shell with thickness of about 1.5 nm. The electrochemical results reveal that the CeO2@C nanocomposites show a wide electrochemical active window of −1.0 ∼ 0.8 V and a specific capacitance of 141.56 F g−1 at 1 A g−1 in 1.0 M Na2SO4 electrolyte. In addition, an asymmetric supercapacitor (ASC) assembled with CeO2@C and poly(3,4-ethylene dioxythiophene) (PEDOT) can work in the wide operational voltage region of 2.0 V and deliver the energy density of 11.12 Wh kg−1 at 2000 W kg−1. The present study indicates that the CeO2@C will have a greater advantage in terms of energy density for CeO2 and its carbon-based composites supercapacitor electrodes.