Controllable Synthesis of NiCo2O4/CNT Composites for Supercapacitor Electrode Materials

NiCo2O4/CNT composites were obtained by a hydrothermal process through changing the content of sodium dodecyl sulfate (SDS), followed by an annealing treatment. The addition of different content of SDS affects the morphology, the structure and the capacitive characteristics of NiCo2O4/CNT composites. In comparison with NiCo2O4/CNT composite synthesized without the addition of SDS, the specific capacitance of NiCo2O4/CNT composites prepared with the addition of 0.288, 0.576, 0.864, and 1.152 g of SDS can be increased in defferent degree. Among them, NiCo2O4/CNT composite synthesized with the addition of 0.864 g of SDS exhibits the highest specific capacitance. Its specific capacitance at 0.5 A g(-1) is 574.3 F g(-1), which is 2.01 times as large as that of NiCo2O4/CNT composite synthesized without the addition of SDS. Besides, NiCo2O4/CNT composite with the addition of 0.864 g of SDS exhibits the specific capacitance retention of 75.3% at 8 A g(-1) and initial specific capacitance retention of 111.5% after 1000 cycles, indicating good rate performance and superb cycle performance. All these characteristics demonstrate that NiCo2O4/CNT composite with the addition of 0.864 g of SDS is a promising supercapacitor electrode material.