Effect of Ce-doping on the structure and electrochemical performance of lithium trivanadate prepared by a citrate sol–gel method

Ce-doped Li1+xCeyV3−yO8 (0 ≤ y ≤ 0.015) cathode materials have been prepared through a citrate sol–gel route followed by heating at 550 °C in air. Demonstrated by XRD and elemental mapping, single-phase and homogeneous Li1+xCeyV3−yO8 solid solutions are obtained at y ≤ 0.01, while CeVO4 impurity presents with increasing of y up to 0.015. The Li1+xCeyV3−yO8 at y = 0.01 delivers initial capacity of 262.33 mAh g−1 and capacity retention of 98.9% within the first 50 cycles, much better than the pristine Li1+xV3O8 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 2.3 V 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 2.55 V upon cycling and the dissolution of active material in the electrolyte on the 2.3 V phenomena.

► Li1+xCeyV3−yO8 (0 ≤ y ≤ 0.015) have been prepared through a citrate sol–gel route.
► Li1+xCeyV3−yO8 at y = 0.01 shows much better cycliabilty than the pristine material.
► Ce doping suppresses the discharge capacity fading derived from the 2.55 V phenomena.