Hollow Porous VO_x/C Nanoscrolls as High-Performance Anodes for Lithium-Ion Batteries

Novel hollow porous VO_x/C nanoscrolls are synthesized by an annealing process with the VO_x/octadecylamine (ODA) nanoscrolls as both vanadium and carbon sources. In the preparation, the VO_x/ODA nanoscrolls are first achieved by a two-phase solvothermal method using ammonium metavanadat as the precursor. Upon subsequent heating, the intercalated amines between the vanadate layers in the VO_x/ODA nanoscrolls decompose into gases, which escape from inside the nanoscrolls and leave sufficient pores in the walls. As the anodes of lithium-ion batteries (LIBs), such hollow porous VO_x/C nanoscrolls possess exceedingly high capacity and rate capability (904 mAh g^-1 at 1 A g^-1) and long cyclic stability (872 mAh g^-1 after 210 cycles at 1 A g^-1). The good performance is derived from the unique structural features of the hollow hierarchical porous nanoscrolls with low crystallinity, which could significantly suppress irreversible Li⁺ trapping as well as improve Li⁺ diffusion kinetics. This universal method of annealing amine-intercalated oxide could be widely applied to the fabrication of a variety of porous electrode materials for high-performance LIBs and supercapacitors.