High Capacity Li – O2 Cell and Electrochemical Impedance Spectroscopy Study

Investigations on Li-air cell have gained great interest in recent years. In the present work, Li-O 2 cells are fabricated with dual layer carbon electrodes consisting of an active layer and a diffusion layer employing a high surface area carbon. Discharge capacity measured at a current density of 0.18 mA cm -2 is as high as 3100 mAh g -1 , which corresponds to 34 mAh cm -2 . Impedance spectra recorded during different stages of cell discharge suggest that the cell resistances increase gradually due to accumulation of reaction products of O 2 reduction, namely, Li 2 O 2 and Li 2 O inside the pores of carbon electrode.