Shaped-controlled synthesis of porous NiCo2O4 with 1-3 dimensional hierarchical nanostructures for high-performance supercapacitors

Abstract

Nickel/cobalt-based precursors (NCP) with 1-3 dimensional (1-3D) nanostructures were synthesized via a facile hydrothermal method. The as-prepared NCP were then transformed into porous NiCo₂O₄ materials by calcination at 300 °C in air for 3 hours. The morphologies of the calcined samples retained a porous texture after calcination, where various 1-3D hierarchical nanostructures, including 2D nanobelts, interconnected 2D nanosheets forming a 3D structure, 1D nanoneedles assembled into chestnuts and 3D nanosponges, were formed. The as-derived structures were then evaluated as electrode materials for supercapacitors in virtue of their high surface areas (99–134 m² g⁻¹). The results show that these porous NiCo₂O₄ materials exhibited promising pseudo-capacitance with good cycling performance. The nanosponge sample registered the highest specific capacitance of 832 F g⁻¹ at a CV scan rate of 1 mV s⁻¹ due to its unique structure and highest surface area.