Preparation of CoAl layered double hydroxide nanoflake arrays and their high supercapacitance performance

Porous cobalt aluminum layered double hydroxide (CoAl-LDH) nanoflake arrays on nickel foam were synthesized by a facile hydrothermal synthesis method. The obtained CoAl-LDH film consisted of interconnected nanoflakes with the thicknesses of ~ 20 nm and showed an extended net-like structure. The electrochemical performance of CoAl-LDH nanoflake arrays was tested by cyclic voltammetry and galvanostatic charge/discharge test. The porous CoAl-LDH nanoflake arrays showed good pseudocapacitive performances with high capacitance and good cycle stability. At room temperature, the porous CoAl-LDH nanoflake arrays exhibited a high specific capacitance of 930 F/g at 2 A/g and their specific capacitances were still up to 669 F/g at 16 A/g. A good cycling stability was also observed for the CoAl-LDH nanoflake arrays with a capacitance retention of 88.9% of the highest value after 2000 cycles at 2 A/g.