Performance of electrostatic spray-deposited vanadium pentoxide in lithium secondary cells

Abstract

A vanadium pentoxide (V2O5) thin-film is deposited on to a platinum substrate using an electrostatic spray deposition (ESD) technique and its performance in a secondary lithium cell is reported for the first time. The deposited thin-film is characterized in terms of structure and surface morphology using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The XRD studies reveals that the structure of the thin V2O5 film is amorphous. The crystallinity increases with rise in the annealing temperature from 200 to 275 degreesC and is composed of orthorhombic V2O5 crystals. Scanning electron micrographs indicate the near-porous nature of the annealed thin-film. The electrochemical behavior of the thin-film of vanadate is investigated by means of cyclic voltammetry (CV) and galvanostatic discharge-charge cycling using a lithium metal anode in the voltage range 2.0-4.0 V (versus Li metal) in 1 M LiClO4/propylene carbonate (PC) as electrolyte. Good cycleability and high capacity (270 mAh g(-1)) is achieved at a current rate of 0.2C by annealing the thin-film at 275 degreesC. Furthermore, the capacity remains stable even after 25 cycles; excellent capacity retention is observed even at the 1 C rate (260 mAh g(-1)). It is concluded that ESD is an excellent and cheap technique for fabricating thin-films of vanadate for use as cathodes in secondary lithium cells. (C) 2003 Elsevier Science B.V. All rights reserved.