리튬공기전지 양극을 위한 비용-효율적인 바이메탈 촉매 연구

Abstract

With the increased social interest about energy storage system (ESS) and electric vehicles (EV), the lithium-oxygen (Li-O2) battery has been attracting attention due to its high energy density, which is prerequisite for ESS and EV. Li-O2 battery operates by reaction with lithium (anode) and oxygen gas (cathode) introduced from the outside, similar to the fuel cell. However, despite the high energy density, low energy efficiency resulting from the huge voltage gap between charge and discharge makes this system impractical. There have been many efforts to improve energy efficiencies of Li-O2 battery using noble metal nanoparticles catalysts-porous support systems and showed some progress. However, noble metals fundamentally have demerits in economy perspective due to their high cost. To address cost effectiveness of the catalytic air cathodes, we focused on a transition metal-based non-noble metal catalyst FeCo. Herein, we tried a novel design strategy for constructing a new functional porous catalyst system. FeCo-CNT air electrodes not only exhibited higher efficiency (72.15%) than that of pristine CNT (62.57%) but also higher capacity (3600 mAh g-1 vs 1276 mAh g-1). The improvement of cell performance with the FeCo catalyst was confirmed through spectroscopic and electrochemical analyses. As a pioneering work on cost-effective non-noble metal catalysts, we expect that FeCo-CNT can raise the possibility for the practical application of lithium-oxygen (Li-O2) systems.