Flocky MnO2/carbon nanotube composites electrodeposited under supergravity field for supercapacitors

A kind of novel flocky MnO2/carbon nanotube (CNT) composites for supercapacitors were successfully electrodeposited in manganese acetate and CNT solution under supergravity field. The supergravity field plays an important role in synthesizing the composites, and it is an essential prerequisite. There is hardly any composite synthesized under normal gravity. CNTs were pretreated by hydrothermal method. The structure of the samples was characterized by X-ray diffraction. The results show that the MnO2/CNT composites are successfully synthesized under supergravity field. The morphology of CNTs and the composites is observed by field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). Results show that the morphologies of CNTs treated with 100 A degrees C and the following synthesized composites are the best. Galvanostatic charge/discharge measurements are applied to investigate electrochemical performances of the MnO2/CNT composites. The composite electrodeposited using the CNTs treated under 100 A degrees C in the electrodepositing solution exhibits the highest discharge capacitance, the value of which is 277.34 F g(-1). It is found that supergravity field can not only synthesize the MnO2/CNTs composite easily but also better disperse CNTs.