New strategy toward enhanced air electrode for Li-air batteries: apply a polydopamine coating and dissolved catalyst

In this article, we report a new strategy for enhancing the electrochemical performance of Li-air batteries through the combined use of polydopamine-coated carbon nanotubes (CNTs) and a dissolved LiI catalyst. The polydopamine layer modified the CNT surface from hydrophobic to hydrophilic, improving the wettability of the CNT-based electrode. This, in turn, increased the area of the electrode that actively participates in the reaction between the lithium ions and the dissolved oxygen in the electrolyte. LiI contained in the electrolyte effectively decreases the overpotential of the Li-air cell, by freely accessing the whole surface of the wetted electrode. We introduced the polydopamine-coated CNTs and LiIdoped electrolyte as an alternative to electrodes composed of carbon and solid catalysts. The electrochemical properties of this new system, including its capacity, overpotential, and cyclic performance, were characterized.