Hydrothermal Synthesis of NiCo 2 O 4 /Activated Carbon Composites for Supercapacitor with Enhanced Cycle Performance

Owing to the advantages of the good conductive AC and high capacitive NiCo 2 O 4 , We prepared a series of NiCo 2 O 4 /AC composites by a hydrothermal method. The morphology of NiCo 2 O 4 /AC composites indicate the NiCo 2 O 4 nanoplates with diameters of about 0.5∼1 μm and thickness of about 20 nm are coated on AC. The electrochemical investigation demonstrate that the specific capacitances of NCO‐AC‐3 (containing 47 % NiCo 2 O 4 ) are 273.5 F g −1 and the capacity retention still retains at 96 % (262.6 F g −1 ) after 3000 cycles at current density of 1 A g −1 , especially, the cycling stability maintain more stable at high current density. Therefore, the low‐cost NiCo 2 O 4 /AC composites can serve as a promising electrode material for high performance supercapacitors due to the synergistic effect between the electric double‐layer capacitance of porous AC and the pseudocapacitance of NiCo 2 O 4 nanoplates.