Facile synthesis of carbon nanotube-supported NiO//Fe2O3 for all-solid-state supercapacitors

We have successfully prepared iron oxide and nickel oxide on carbon nanotubes on carbon cloth for the use in supercapacitors via a simple aqueous reduction method. The obtained carbon cloth-carbon nanotube@metal oxide (CC-CNT@MO) three-dimensional structures combine the high specific capacitance and rich redox sites of metal oxides with the large specific area and high electrical conductivity of carbon nanotubes. The prepared CC-CNT@Fe2O3 anode reaches a high capacity of 226 mAh.g(-1) at 2 A.g(-1) with a capacitance retention of 40% at 40 A.g(-1). The obtained CC-CNT@NiO cathode exhibits a high capacity of 527 mAh.g(-1 )at 2 A.g(-1) and an excellent rate capability with a capacitance retention of 78% even at 40 A.g(-1). The all-solid-state asymmetric supercapacitor fabricated with these two electrodes delivers a high energy density of 63.3 Wh.kg(-1) at 1.6 kW.kg(-1) and retains 83% of its initial capacitance after 5000 cycles. These results demonstrate that our simple aqueous reduction method to combine CNT and metal oxides reveals an exciting future in constructing high-performance supercapacitors.