Porous V2Os-SnO2/CNTs composites as high performance cathode materials for lithium-ion batteries

摘要

Vanadium pentoxide (V2O5 ) exhibits high theoretical capacities when used as a cathode in lithium ion batteries (LIBs), but its application is limited by its structural instability as well as its low lithium and electronic conductivities. A porous composite of V2O5 -SnO2 /carbon nanotubes (CNTs) was prepared by a hydrothermal method and followed by thermal treatment. The small particles of V2O5 , their porous structure and the coexistence of SnO2 and CNTs can all facilitate the diffusion rates of the electrons and lithium ions. Electrochemical impedance spectra indicated higher ionic and electric conductivities, as compared to commercial V2O5 . The V2O5 -SnO2 /CNTs composite gave a reversible discharge capacity of 198 mAh g-1 at the voltage range of 2.05 4.0 V, measured at a current rate of 200 mA g-1 , while that of the commercial V2O5 was only 88 mAh g-1 , demonstrating that the porous V2O5 -SnO2 /CNTs composite is a promising candidate for high-performance lithium secondary batteries.