Journal of Power Sources, Vol.199, 300-307, 2012
Effect of Ce-doping on the structure and electrochemical performance of lithium trivanadate prepared by a citrate sot-gel method
Ce-doped Li(1+x)Ce(y)V(3-y)O(8) (0 <= y <= 0.015) cathode materials have been prepared through a citrate sol-gel route followed by heating at 550 degrees C in air. Demonstrated by XRD and elemental mapping, single-phase and homogeneous Li(1+x)Ce(y)V(3-y)O(8) solid solutions are obtained at y <= 0.01, while CeVO(4) impurity presents with increasing of y up to 0.015. The Li(1+x)Ce(y)V(3-y)O(8) at y=0.01 delivers initial capacity of 262.33 mAhg(-1) and capacity retention of 98.9% within the first 50 cycles, much better than the pristine Li(1+x)V(3)O(8) cathode (261.86 mAh g(-1) and 87.7% accordingly). Electrochemical analyses show that an appropriate dosage of Ce can significantly suppress the capacity fading arose from lithiation phenomena around 2.55 and 2.3V upon cycling. These interesting phenomena are mainly attributed to the stabilization of the microstructure of the material and the modification of their crystallinity and grain morphology, which lead to suppression of structural damage from the two-phase transformation around 2.55V upon cycling and the dissolution of active material in the electrolyte on the 2.3V phenomena. (C) 2011 Elsevier B.V. All rights reserved.