کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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6470728 | 1424112 | 2017 | 11 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Evidence for a nanosize effect on the structural and high performance electrochemical properties of V2O5 obtained via fluorine chemistry Evidence for a nanosize effect on the structural and high performance electrochemical properties of V2O5 obtained via fluorine chemistry](/preview/png/6470728.png)
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 13-30 nm range are obtained. Remarkably, this nanostructured V2O5 exhibits outstanding rate capacities and cycling stabilities. This material can deliver reversible capacities of 260 mAh gâ1 at 15 mA gâ1 (C/10 rate) and 150 mAh gâ1 at 300 mA gâ1 (2C rate), as well as a stable capacity of 200 mAh gâ1 at C rate after 50 cycles. The unique structural features of nano-LixV2O5 electrodes are determined over the large Li composition range 0 â¤Â 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.
Journal: Electrochimica Acta - Volume 245, 10 August 2017, Pages 350-360