Low temperature electrochemical performance of β-LixV2O5 cathode for lithium-ion batteries

The low temperature electrochemical behavior of β-LixV2O5 as cathode material was investigated by galvanostatic charge/discharge test and electrochemical impedance spectroscopy. The β-LixV2O5 cathode exhibited unusual high capacity retention ratio upon 100 cycles under subzero temperatures: 88.6% at −40 °C, 79.5% at −20 °C, and 82.3% at 0 °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 °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 β-LixV2O5 electrode is controlled by the sluggish charge-transfer kinetics as well as solid-state ionic diffusion.