Construction of NiCo2S4 wrapped CeO2/Co3O4 nanorod arrays for excellent performance supercapacitors

Abstract

Supercapacitor (SC) electrodes with excellent capacity and multiplicity performance have been in demand for a long time. In this paper, CeO₂/Co₃O₄ nanorod arrays were firstly synthesized by hydrothermal method and thermal treatments, and then NiCo₂S₄ were successfully wrapped around CeO₂/Co₃O₄ nanorod arrays by electrodeposition. On the one hand, the CeO₂/Co₃O₄ nanorod arrays acted as a core layer to provide a scaffold for the continuous and stable conductivity of the electrochemical reaction, while on the other hand, the NiCo₂S₄ played an important role in increasing the capacity due to their high conductivity. The electrochemical properties of NiCo₂S₄@ CeO₂/Co₃O₄ electrode materials were remarkable improvement due to the synergistic and complementary effect. The area capacitance of the prepared NiCo₂S₄@ CeO₂/Co₃O₄ nanorod arrays was 1576.67 mF cm⁻² with a current density of 1 mA cm⁻². And the intrinsic and transfer resistances of the composites were 0.816 Ω and 0.064 Ω. Meanwhile, the asymmetrical supercapacitors exhibited excellent energy density (0.074 mWh cm⁻²) with the power density of 0.805 mW cm⁻². The capacitive retention rate after 5000 cycles was 93.25%. This study demonstrates that the 3D core–shell structure of NiCo₂S₄@ CeO₂/Co₃O₄ nanorod arrays has a good practical application potential in supercapacitor devices.