Air electrode based on poly(3,4-ethylenedioxythiophene) microflower/graphene composite for superior Li-O2 batteries with excellent cycle performance

Abstract

We report the use of poly(3,4-ethylenedioxythiophene) (PEDOT) microflowers as a potential electrode material for Li-O2 batteries. PEDOT is a conducting polymer that shows catalytic activity for the formation and dissociation of Li2O2 in Li-O2 cells. The microflower morphology composed of intertwined nanofibers is expected to increase the number of active sites for the redox reaction during the discharging-charging process. Although the electronic conductivity of the PEDOT microflowers is not so low, it is insufficient to achieve a large capacity for the electrode material in Li-O2 cells. Thus, a composite was prepared using 5-20 wt% of graphene as the matrix to compensate for the low conductivity of the PEDOT microflowers. The electrode employing the PEDOT microflower/graphene composite presents much higher capacity than that of the electrode employing pristine PEDOT microflowers, because of the enhanced electronic conductivity. Moreover, the electrode shows enhanced cycle performance compared to that of the electrode employing pristine graphene. This is because the microflower surface can suppress the side reactions activated by carbon, thereby reducing the accumulation of unwanted reaction products on the electrode.