Synthesis of NiCo 2 O 4 Nanoneedles on rGO for Asymmetric Supercapacitors

NiCo 2 O 4 nanoneedles were grown on reduced graphene oxide (rGO) by a hydrothermal method. Physical characterization and electrochemical tests were performed on the composites. The NiCo 2 O 4 /rGO composites possessed a high capacitance of 1757 F g −1 (1 A g −1 ). The composites possessed 97.3% of initial capacity after 2500 cycles (10 A g −1 ). Furthermore, the prepared NiCo 2 O 4 /rGO//AC asymmetric supercapacitor obtained a well energy density of 32.38 W h kg −1 . After 10000 cycles at 5 A g −1 , 90.4% of the capacity was retained. Therefore, the NiCo 2 O 4 /rGO nanocomposites appear to be excellent candidates for high performance supercapacitors.