Core-shell CoMoO₄@Ni(OH)₂ on ordered macro-porous electrode plate for high-performance supercapacitor

Abstract

Multidimensional CoMoO₄@Ni(OH)₂ nanocomposite materials are fabricated on the nickel modified surface and channels of an ordered macro-porous electrode plate (OMEP) by a multistep high temperature hydrothermal method as the supercapacitor electrode in a high power density energy storage device. The effects, morphology, capacitive properties, and formation mechanism of the CoMoO₄@Ni(OH)₂ composite materials are systematically investigated. Compared to nanostructured nickel grown on the OMEP or CoMoO₄@Ni(OH)₂ on nickel plate with the same area, the CoMoO₄@Ni(OH)₂/OMEP shows enhanced electrochemical energy storage properties such as high energy capacitance of 8.55 F cm−2 (1812.42 F g−1) at 2 mA cm−2 and good cycling stability of 87.42% capacity retention after 5000 cycles. An asymmetrical supercapacitor (ASC) device is assembled with a polyethylene (PE) membrane, CoMoO₄@Ni(OH)₂/OMEP, and active carbon covered nickel foam. The ASC with the CoMoO₄@Ni(OH)₂/OMEP has an energy density of 9.66 Wh Kg−1 even at a power density of 3000 W Kg−1 as well as stable power characteristics with 86.5% retention after 10,000 cycles at a current of 0.06 A. The device produces large instantaneous power after charging at 2.8 V for 10 s one ASC can power a 5 mm red LED with high efficiency.