Controllable morphologies and electrochemical properties of graphitizing MCMB-based hybrids with nanostructure via a simple chemical vapor deposition method

The graphitizing mesocarbon microbeads (g-MCMB) based nanostructure hybrids are prepared by a simple chemical vapor deposition method. The growth temperature and the flow ratio of H-2 to C2H2 (r) are the key parameters of controlling the morphologies of the hybrids. When r is 4, many CNTs mixed with carbon fibers grow on g-MCMB surfaces at 700 degrees C. However, there are almost no CNTs to be observed at 750 degrees C and 800 degrees C. In addition, the specific surface area of as-prepared hybrids is a little higher than that of g-MCMB, and the specific capacitance is much higher than the latter. The sample of g-MCMB-NS-4-700 exhibits the highest specific capacitance (303 F.g(-1) at the current density of 0.5 A g(-1)), which is approximately 1.46 folds of g-MCMB. Moreover, the prepared hybrids have an excellent cycling stability and the specific capacitance retention is above 90% after 500 cycles. (C) 2017 Elsevier B.V. All rights reserved.