Enhanced electrochemical properties of Al2O3-coated LiV3O8 cathode materials for high-power lithium-ion batteries

Surface modified-LiV 3 O 8 cathode materials with Al 2 O 3 are successfully synthesized via a facile thermolysis process. The 0.5 wt.% Al 2 O 3 -coated LiV 3 O 8 exhibits an enhanced cyclic stability at various charge–discharge current densities. At a current density of 100 mA g −1 , it delivers an initial specific discharge capacity of 283.1 mAh g −1 between 2.0 and 4.0 V. Moreover, high capacities of 139.4 and 118.5 mAh g −1 are obtained at the 100th cycle at current densities of 2000 and 3000 mA g −1 , respectively. The improved electrochemical performance is attributed to the Al 2 O 3 coating, which can hinder the irreversible phase transformation and act as a protective layer to prevent the active material from direct contact with electrolyte. Furthermore, the formation of a Li–V–Al–O solid solution at the LiV 3 O 8 /Al 2 O 3 interface provides a fast Li + diffusion path which is of benefit to the electrochemical behaviors.