Facile fabrication of nanocomposites of nickel hydroxide and copper oxide for high performance asymmetric supercapacitors

Abstract

Nowadays, supercapacitors have been among popular electrochemical energy storage devices in modern life. Plenty of active materials have been investigated and developed to meet the increasing demands for high performance supercapacitors. In this study, we introduce a facile chemical synthesis route in combination with a subsequent calcination process to fabricate the oxide/hydroxide composites of nickel (Ni) and copper (Cu) as active materials for high performance asymmetric supercapacitors. Effects of the composition and calcination temperatures on the electrochemical performance of supercapacitors have been investigated systematically. The optimum composite was the sample calcinated at 200°C and containing nickel hydroxide and copper oxide with a molar Ni/Cu ratio of 1:1. At a specific current of 1 A.g⁻¹ the composite electrode could offer a high specific capacitance of 684.2 F.g⁻¹. In addition, at the higher specific current of 3 A.g⁻¹ the electrode supplied a relatively high specific capacitance of 526.3 F.g⁻¹ for the first cycle. After longterm test of 1000 cycles of charge discharge, the electrode maintained 91.7% of the initial specific capacitance. This suggests the high application potential of synthesized optimum composite for supercapacitors.