Carbon nanotube/Co₃O₄ nanocomposites selectively coated by polyaniline for high performance air electrodes

We herein report the preparation of carbon nanotube (CNT)/Co₃O₄ nanocomposites selectively coated with polyaniline (PANI) via an electropolymerization method, for use as an effective electrode material for Li-air (Li-O₂) batteries. The Co₃O₄ catalyst attached to the CNTs facilitated the dissociation of reaction products and reduced the overpotential of the cells. As the carbon surface activates the side reactions, the PANI coating on the carbon surface of the electrode suppressed the side reaction at the electrode/Li₂O₂ and electrode/electrolyte interfaces, thus enhancing the cycle performance of the electrode. In addition, the catalytic activity of Co₃O₄ on the CNT/Co₃O₄ nanocomposites remained unaffected, as the Co₃O₄ surface was not covered with a PANI layer due to the nature of the electropolymerization method. Overall, the synergic effect of the PANI layer and the Co₃O₄ catalyst leads to a superior cyclic performance and a low overpotential for the electrode based on selectively PANI-coated CNT/Co₃O₄ nanocomposites.