Self-assembled Co-Al LDH and TiO2 nanocomposites as a novel electrode for supercapacitors

Abstract

A novel Co-Al layered double hydroxide/titanium dioxide (Co-Al LDH/TiO2) nanocomposite is fabricated by the electrostatic assembly of Co-Al LDH and TiO2 nanosheets from exfoliation. The layer-by-layer nanocomposite structure effectively improves the electrochemical performance by providing abundant utilization of active sites and facilitating rapid ionic/electronic transport. The Co-Al LDH/TiO2 electrode exhibits an enhanced specific capacitance of 611.4 F g−1 at a current density of 10 mA cm−2 and good cyclic stability (81.4% capacity retention after 2000 cycles) compared with Co-Al LDH. A solid-state asymmetric supercapacitor is prepared from the Co-Al LDH/TiO2 as positive electrode and active carbon as negative electrode. The Co-Al LDH/TiO2//AC retains 92.7% initial capacitance and 94.1% coulombic efficiency after 2000 cycles at 20 mA cm−2. The Co-Al LDH/TiO2 nanocomposite is a promising electrode material for the supercapacitors.