Three-dimensional heterostructured MnO₂/graphene/carbon nanotube composite on Ni foam for binder-free supercapacitor electrode

ABSTRACT

In this article, three-dimensional (3D) heterostructured of MnO₂/graphene/carbon nanotube (CNT) composites were synthesized by electrochemical deposition (ELD)-electrophoretic deposition (EPD) and subsequently chemical vapour deposition (CVD) methods. MnO₂/graphene/CNT composites were directly used as binder-free electrodes to investigate the electrochemical performance. To design a novel electrode material with high specific area and excellent electrochemical property, the Ni foam was chosen as the substrate, which could provide a 3D skeleton extremely enhancing the specific surface area and limiting the huge volume change of the active materials. The experimental results indicated that the specific capacitance of MnO₂/graphene/CNT composite was up to 377.1 F g⁻¹ at the scan speed of 200 mV s⁻¹ with a measured energy density of 75.4 Wh kg⁻¹. The 3D hybrid structures also exhibited superior long cycling life with close to 90% specific capacitance retained after 500 cycles.

KEYWORDS:

• Graphene
• carbon nanotube
• heterostructured MnO₂
• supercapacitor

Acknowledgments

This work was supported by the National Natural Science Foundation of China (No. 51672221), China Aeronautical Science Fund (No. 2014ZF53074), and the Key Science and Technology Program of Shaanxi Province, China (No. 2013K09-03).