CNT/Co3O4 Based Air Electrode Selectively Wrapped By Polyaniline for High Performance Air Electrode

Abstract

Li-Air battery is one of the most promising new energy storage systems because they provide much higher energy densities than lithium-ion batteries. Nevertheless, Li-air batteries have several issues to be solved before the commercialization. One of them is side reaction attributed to the reaction between carbon, a general component of the air electrode, and electrolyte/Li2O2. Actually, carbon with high surface area provides a large reaction sites to form and store the reaction products. And it compensates for the low electronic conductivity of oxide catalysts such as MnO2 and Co3O4. However, some studies have suggested that the carbon promotes side reaction such as electrolyte decomposition and formation of Li2CO3. The unwanted reaction products formed from side reaction is hardly decomposed on charging process. This results in the accumulation of reaction products on the surface of electrode during cycling, which leads to limited cycle life and high over-potential. As a new approach to address these issues, nano-sized cobalt oxide (Co3O4) particles were composited with carbon nanotube (CNT) to enhance the catalytic activity, and the surface of carbon nanotube was selectively wrapped with polyaniline, a conducting polymer, to suppress the side reaction between carbon (CNT) and electrolyte/Li2O2. CNT/Co3O4 based air electrode selectively wrapped by polyaniline is expected enhanced cyclic performance and low over-potential due to synergic effect of nano-sized Co3O4 catalyst composited with CNT and polyaniline coating layer on the surface of carbon.