Li 2 TiO 3 Powder Effects on LiCoO 2 Electrode Reactions in Lithium Secondary Batteries

The specific capacity of a LiCoO 2 positive electrode containing 10 wt% Li 2 TiO 3 powder ( LCO–10LT ) exceeded that of a LiCoO 2 electrode ( LCO ) alone at current densities up to around 6.0 mA cm -2 . Findings indicate that Li 2 TiO 3 activated the electrode reaction of the LiCoO 2 electrode. The electrochemical impedance spectroscopy (EIS) using a symmetrical cell of 30 wt% Li 2 TiO 3 powder ( LCO–30LT ) showed a marked decrease in resistance corresponding to a charge transfer at the electrode/electrolyte interface. The activation energy for the charge transfer reaction was 6 kJ mol -1 lower for LCO-30LT than for LCO . Furthermore, the charge–discharge curves of LCO-30LT at 5 °C were nearly identical to those of LCO at 25 °C, demonstrating the improved low-temperature performance and supporting the decreased activation energy.