The composite membranes based on group 5 metals are capable of H-2 separation with high speed and infinite selectivity. Hydrogen transport through Pd-V-Pd composite membranes of planar and tubular shape was investigated in the pressure range of (1 x 10(-8)-6 x 10(-1)) MPa at 400 degrees C. Due to the wide pressure range both the diffusion rate limited regime of hydrogen permeation and the regime limited by the H-2 molecule dissociation were observed in one experiment. The density of flux permeating through the 100 mu m-membrane reached 2.4 scc/(cm(2) s) that seems to be one of highest ever achieved in the membranes based on group 5 metals as well as in any other unsupported metallic membranes. The concentration of dissolved hydrogen c(H)/c(V) reached 0.42 but no noticeable reduction in hydrogen diffusivity was found. The constant value of sticking probability of H-2 molecules (4 x 10(-4)) that was observed over full range of pressures used in this study indicates that the surface saturation has insignificant influence on the kinetics of boundary processes. The 100-fold cycling of hydrogen pressure from 0 to 0.6 MPa did not result in any loss of tubular membrane integrity and change of its shape despite the fact that the ductile-to-brittle transition occurred in each cycle. The operation with samples of planar and tubular shape demonstrated that V-based composite membranes can be used at least for laboratory studies. Further work to improve the long-term stability is necessary for their practical applications. (C) 2014 Elsevier B.V. All rights reserved.