Electrochemical behavior and structural stability of LiV3O8 microrods as cathode for lithium-ion batteries

摘要

LiV3O8 microrods were prepared by high-temperature calcination of hydrous lithium vanadium oxide nanobelts at 400-600 degrees C, and the correlation between electrochemical behavior and calcination temperature was revealed by cyclic voltammetry and charge-discharge tests. The structural stability of LiV3O8 microrods cathode can be enhanced by increasing calcination temperature. Specifically, LiV3O8 rods treated at 600 degrees C with length of 1-2 mu m and width around 1 mu m delivers a moderate discharge capacities of 212.8 mA h g(-1) in the potential range of 2.0-4.0 V, and excellent capacity retention of 80.5% after 100 cycles at current density of 60 mA g(-1). Electrochemical impedance spectroscopy analysis of LVO600 electrode under different depth of discharge/charge shows that the charge transfer resistance (R-ct) increases with decreasing discharge potential, which can be related to the single-phase lithium insertion process, two-phase transformation between Li1+x V3O8 (1 <= x <= 2) and LiV3O8, and the slower kinetic insertion step in LiV3O8 phase, respectively. The outstanding cycling performance of LiV3O8 microrods can be attributed to the balance between particle size and high crystallinity as well as the excellent structural stability as evidenced by ex-situ XRD. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.