TEMPERATURE DEPENDENCY OF THE DISCHARGE AND CHARGE CHARACTERISTICS OF ELECTROCHEMICAL LITHIUM INSERTION IN V6O13

The discharge properties of the Li-V6O13 system have been investigated using the electrochemical voltage spectroscopy (EVS) technique in the temperature range 3 to 53 degrees C. Generally, the utilization of the active material improves as the temperature increased. Only at the higher temperatures does the system appear to approach true thermodynamic equilibrium. It is shown that at the temperatures extremes used during this study, the fully discharged active material (1.80 V versus Li/Li+) compositions approximate to Li6.0V6O13 and Li7.2V6O13. It is also demonstrated that in addition to this diminished discharge capacity at the lower temperatures there is a substantially increased discharge-charge hysteresis due to temperature-induced polarization effects.