Hierarchically porous cobalt aluminum layered double hydroxide flowers with enhanced capacitance performances

A facile and cost-efficient synthesis approach toward hierarchically porous cobalt aluminum layered double hydroxide with hydrangea flower-like morphology (PCALs) is developed in this work via the hydrothermal treatment of cobalt- and aluminum-containing precursors under basic conditions following etching with NaOH. The architectures and porosities of the obtained PCALs can be easily modified by the fabrication conditions such as the concentration of the starting materials and the time of etching, which can further influence their electrochemical behavior. As the electrode material in a three-electrode supercapacitor, the PCALs can deliver a high capacitance of 550 F g−1 for 1000 cycles with a retention rate over 82% at 10 A g−1. In addition, the asymmetric capacitor using PCALs as cathode and active carbon as anode also exhibits an excellent capacitance of 103.5 F g−1 at 0.5 A g−1, indicating their potentials in the applications of energy storages.