Electrochimica Acta, Vol.169, 440-446, 2015
Low temperature electrochemical performance of beta-LixV2O5 cathode for lithium-ion batteries
The low temperature electrochemical behavior of beta-LixV2O5 as cathode material was investigated by galvanostatic charge/discharge test and electrochemical impedance spectroscopy. The beta-LixV2O5 cathode exhibited unusual high capacity retention ratio upon 100 cycles under subzero temperatures: 88.6% at -40 degrees C, 79.5% at -20 degrees C, and 82.3% at 0 degrees C while only 55.0% at room temperature. Electrochemical impedance spectroscopy results indicate that the charge-transfer resistance increases sharply and the lithium diffusion coefficient decreases gradually as temperature dropping to -40 degrees C. According to Randles plot and Arrhenius equation, the activation energies for charge-transfer and solid-state lithium diffusion at 20% state of charge are 43.28 and 47.96 kJ mol(-1), respectively, suggesting that the electrochemical process dynamics of the beta-LixV2O5 electrode is controlled by the sluggish charge-transfer kinetics as well as solid-state ionic diffusion. (C) 2015 Elsevier Ltd. All rights reserved.
Keywords:beta-LixV2O5 cathode;lithium-ion batteries;low temperature performance;lithium diffusion coefficient