In this study, we demonstrate the benefit of an original vanadium pentoxide (V2O5) nanostructuration on the electrochemical performances. This new synthesis way of high purity nanosized V2O5 consists in a facile fluorination reaction of micro-V2O5 in aqueous solution followed by a heat-treatment at low temperature (230°C). Highly porous calisson-like particles with crystallite sizes in the 13–30nm range are obtained. Remarkably, this nanostructured V2O5 exhibits outstanding rate capacities and cycling stabilities. This material can deliver reversible capacities of 260mAhg−1 at 15mAg−1 (C/10 rate) and 150mAhg−1 at 300mAg−1 (2C rate), as well as a stable capacity of 200mAhg−1 at C rate after 50 cycles. The unique structural features of nano-LixV2O5 electrodes are determined over the large Li composition range 0≤x<2 based on XRD and Raman microspectrometry experiments. We provide evidence that lithiation in nanosized V2O5 proceeds via solid solution state without domain boundaries: a single phase behavior of the ε’-type whose interlayer distance and unit cell volume linearly increase with x is revealed. This constitutes a disruption of the usual mirco-LixV2O5 phase diagram made of the successive appearance of the (α/ε), (ε/δ) and (δ/γ) wide biphasic regions. These limited and reversible structural changes combined with shorter Li diffusion pathways explain the huge improvement in electrochemical performances of nano-V2O5. These findings fully elucidate the peculiar voltage profile of nanosized V2O5 and give a unique insight into the impact of nanostructures in terms of electrochemistry and solid state chemistry.