Electrochemical properties of spherically shaped dense V2O5 cathode powders prepared directly by spray pyrolysis

Spherically shaped vanadium pentoxide (V2O5) cathode powders with porous or dense morphologies are prepared directly via spray pyrolysis by varying the preparation temperatures between 600 and 1000 degrees C. The powders prepared at 600 degrees C consist of nanometer-sized rod-shaped crystals with porous structures. The V2O5 powders prepared at 1000 degrees C have spherical shapes, clean surfaces, and dense structures, because of complete melting of the powders that occurs inside the hot-wall reactor. The Brunauer-Emmett-Teller (BET) surface areas of the V2O5 powders decrease from 24.7 to 3.2 m(2) g(-1) when the preparation temperature increases from 600 to 1000 degrees C. The V2O5 powders prepared at 1000 degrees C have better cycle properties than those prepared at 600 and 800 degrees C. The discharge capacity of the V2O5 powders prepared at 1000 degrees C decreases from 432 mAh g(-1) to 263 mAh g(-1) after 20 cycles, in which the capacity retention is 61%. (C) 2012 Elsevier B.V. All rights reserved.