Synthesis of mesoporous NiO nanoflake array and its enhanced electrochemical performance for supercapacitor application

Abstract

Highly porous metal oxide nanoflake arrays are important for developing high-performance electrochemical devices. Herein, mesoporous NiO nanoflake arrays have been successfully prepared by a facile hydrothermal synthesis method. Except for the mesoporous walls, the NiO nanoflakes are interconnected with each other to form macroporous structure. This porous structured NiO nanoflake arrays possess a high specific surface area of ∼185m2g−1. The supercapacitor performance of the mesoporous NiO nanoflake arrays is fully characterized. The mesoporous NiO nanoflake arrays exhibit weaker polarization, higher specific capacitance and better rate capability than the common NiO nanoflake arrays. The mesoporous NiO nanoflake arrays deliver a specific capacitance of 400Fg−1 at 2Ag−1 and 339Fg−1 at 40Ag−1, respectively, higher than those of the common NiO nanoflake arrays (287Fg−1 at 2Ag−1 and 179Fg−1 at 40Ag−1). The enhanced performance is mainly due to the hierarchical pore system in the mesoporous NiO nanoflake arrays.