We demonstrate the successful synthesis of carbon nanotubes (CNTs) on in situ formed siliceous micro-flakes by one-step pyrolyzation of polypropylene/(methyl MQ silicone)/Ni-Mo-Mg blends. An appropriate concentration of methyl MQ silicone in blends acts as a key factor for the formation of this kind of Si-C nanohybrid. CNTs growing on nano- or micro-scale siliceous flakes were acquired by directly pyrolyzing polypropylene with 12 wt% methyl MQ silicone and 5 wt% catalysts. The product was systematically characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. A formation mechanism was also proposed. A tentative application for the obtained Si-C nanohybrids as anode materials of lithium-ion batteries was evaluated. Excellent electrochemical performance including cycle capacity and coulombic efficiency was confirmed. The current approach provides a very promising avenue for fabricating Si-C nanohybrids, studies of further applications of which are under way.