Three-Dimensional Nickel Oxide@Carbon Hollow Hybrid Networks with Enhanced Performance for Electrochemical Energy Storage

In this paper, the novel nickel oxide@carbon (NiO@C) hollow hybrid networks (HHNs) consisted of nanotubes with interconnected branches are designed and fabricated via template-assisted electrode-position method. Electrochemical measurements demonstrate that the NiO@C HHNs electrodes exhibit high specific capacitance (C-sp) (572.5 F/g) at current density of 2.5 A/g, which is more than twice as that of NiO hollow networks (HNs) electrode (259.6 F/g). The NiO@C HHNs electrodes show high flexibility and excellent cycle performance (almost no capacitance loss after 2000 cycles) and exhibit superior rate capability (similar to 14% C-sp decay with scan rate increasing from 5 to 100 mV/s). The assembled asymmetric supercapacitors (ASCs) based on NiO@C HHNs as positive electrodes and 3D active carbon (AC) as negative electrodes also shows high specific capacitance, excellent cycle performance, and high energy and power densities. Two ASC device units connected in series could drive a red light-emitting diode (LED, 2.0 V) well for more than 60 s after charging at 28 A/g for 10 s. The above results indicate that the NiO@C HHNs own promising potential for electrochemical energy storage. (C) 2014 Elsevier Ltd. All rights reserved.