title: Nanorod niobium oxide as powerful catalysts for an all vanadium redox flow battery.
abstract: A powerful low-cost electrocatalyst, nanorod Nb2O5, is synthesized using the hydrothermal method with monoclinic phases and simultaneously deposited on the surface of a graphite felt (GF) electrode in an all vanadium flow battery (VRB). Cyclic voltammetry (CV) study confirmed that Nb2O5 has catalytic effects toward redox couples of V(II)/V(III) at the negative side and V(IV)/V(V) at the positive side to facilitate the electrochemical kinetics of the vanadium redox reactions. Because of poor conductivity of Nb2O5, the performance of the Nb2O5 loaded electrodes is strongly dependent on the nanosize and uniform distribution of catalysts on GF surfaces. Accordingly, an optimal amount of W-doped Nb2O5 nanorods with minimum agglomeration and improved distribution on GF surfaces are established by adding water-soluble compounds containing tungsten (W) into the precursor solutions. The corresponding energy efficiency is enhanced by ∼10.7% at high current density (150 mA·cm(-2)) as compared with one without catalysts. Flow battery cyclic performance also demonstrates the excellent stability of the as prepared Nb2O5 catalyst enhanced electrode. These results suggest that Nb2O5-based nanorods, replacing expensive noble metals, uniformly decorating GFs holds great promise as high-performance electrodes for VRB applications.
authors.affiliation: Pacific Northwest National Laboratory , P.O. Box 999, Richland, Washington 99352, United States.
authors.forename: Bin
authors.initials: B
authors.lastname: Li
authors.forename: Meng
authors.initials: M
authors.lastname: Gu
authors.forename: Zimin
authors.initials: Z
authors.lastname: Nie
authors.forename: Xiaoliang
authors.initials: X
authors.lastname: Wei
authors.forename: Chongmin
authors.initials: C
authors.lastname: Wang
authors.forename: Vincent
authors.initials: V
authors.lastname: Sprenkle
authors.forename: Wei
authors.initials: W
authors.lastname: Wang