Nanostructured V2O5/Nitrogen-doped Graphene Hybrids for High Rate Lithium Storage

ABSTRACTVanadium Pentoxide (V2O5) has been identified as a potential cathode material owning to its high specific capacity, theoretically, 441 mAh g-1 for 3Li+ ions insertion/extraction. However, the intrinsic drawbacks of V2O5, i.e. structural instability and poor electronic and ionic conductivity, greatly inhibit its application as a cathode. Here, we report a cetyltrimethylammonium bromide (CTAB)-assisted hydrothermal reaction to synthesize V2O5 nanoclusters. Unique aggregated fiber structure was obtained after annealing. To achieve a porous structure and increase the conductivity, nitrogen-doped Graphene (NG) suspended in ethylene glycol was added to the reaction mixture. The obtained spherical V2O5 nanoparticles and NG sheets were randomly dispersed in the matrix of the V2O5 spheres. As a cathode material for lithium-ion batteries, the V2O5/NG hybrids demonstrate better rate performance compared to the bundle-like V2O5 fibers, delivering higher specific capacity of ∼ 300 and 150 mAh g-1 at a rate of C/10 and 5C, respectively. The enhanced performance in lithium storage are attributed to the synergistic effect of the nanostructured V2O5/NG composites.